Dissertations / Theses on the topic 'Sugarcane'

The following manuscript is a collection of lyric poetry that touches on themes of family history, love, and labor in the service industry. It is divided into three sections. The speaker in the work dwells in mostly private spaces and deals with private symbols such as, water, to represent the father figure in the poems.

The Brazilian experiment with sugar cane began in Northeastern Brazil during the earliest days of the colonial period. Its cultivation followed the extension of the Portuguese Royal Authority to the present day state of Bahia and the founding of the city of Salvador in 1549. Salvador Bahia became the center of a very complex production and commercialization system that supplies sugar to regional, national and international markets. In 1980, Brazil overtook India as the top global sugarcane producer, title which it holds to this day. Sugar cane’s versatility as a sweetener and a source of ethanol propelled its comeback to the helm of sugarcane producers. . Some of this success is due to the Brazilian government’s support for viable fuel alternatives following the oil shocks of 1973. Naturally, one would assume that in its pursuit to recapture the world market Brazil would have relied on the Northeast’s tradition in sugar production. The statistics, however, indicate that sometime in the 1960s a regional shift occurred. São Paulo is now the leader in sugar production. My research examines the question of how the Northeastern region lost its leadership to São Paulo, a state without any significant history in sugar production. For this research, I employ a mixed-methods approach. I combine historical production data from several reputable governmental and private sources with information compiled during in-depth literature review and an interview with an individual knowledgeable about the circumstances of the local sugar industry. I examine the role that environment, globalization, and technological advances have played in the regional shift of Brazil’s sugar production.

Sugar mills represent significant capital investments. To maintain appropriate returns on their investment, sugar companies seek to run the mills at capacity over the sugarcane harvest season. Because the sugar content of cane degrades considerably once it is cut, maintaining inventories of cut cane is undesirable. Instead, mills want to coordinate the arrival of cut cane with production. We present exact solution approaches exploiting special structure of the sugarcane harvest logistics problem in Brazil and the United States.

Thesis (PhD (Logistics))--University of Stellenbosch, 2010.
ENGLISH ABSTRACT: Computerised sugarcane harvest scheduling decision support is an active fi eld of research which ties in closely with the broader problem of automating and streamlining the various activities in the sugar supply chain. In this dissertation, the problem of providing decision support with respect to sugarcane harvesting decisions is defined within a number of contexts, each representing a typical kind of organisation of sugarcane farmers into a cohesive decision making unit with its speci fic requirements and limitations that exist in practice. A number of variations relevant to these contexts of an overarching tactical sugarcane harvest scheduling problem (THSP) are considered and solved in this dissertation. The THSP is the problem of providing objective, responsible decision support to persons charged with the task of determining optimal harvesting dates for a set of sugarcane fields across an entire season. Sugarcane fields typically diff er in terms of the age, variety, life-cycle stage and in many other properties of the cane grown on them. The growth of sugarcane crops may also be a ffected by environmental conditions such as accidental fires, frosts or storms which have a detrimental e ffect on crop-value. Since sugarcane is a living organism, its properties change over time, an so does the potential pro t associated with it. The practicalities of farming cause further complication of the problem (for example, seasonal changes alter the conditions under which the crop is harvested and transported). The rainy season carries with it the added cost of disallowing long-range vehicles to drive into the fields, forcing the unloading and reloading of cane at so-called loading zones. Other considerations, such as the early ploughing out of fields to allow them to fallow before being replanted, compounds the THSP into a multi-faceted difficult problem requiring efficient data management, mathematical modelling expertise and efficient computational work. In the literature the THSP has been viewed from many different standpoints and within many contexts, and a variety of operations research methodologies have been employed in solving the problem in part. There is, however, no description in the literature of a solution to the THSP that takes the negative e ffects of extreme environmental conditions on the quality of a harvesting schedule into account in a scienti fically justifi able manner; most models in the literature are based on optimising sucrose yield alone under normal conditions, rendering weak schedules in practice. The scope of the modelling and solution methodologies employed in this dissertation towards solving the THSP is restricted to integer programming formulations and approximate solution methods. The parameters associated with these models were determined empirically using historical data, as well as previous work on deterioration of sugarcane following environmental and other events. The THSP is solved in this dissertation by designing a generic architecture for a conceptual decision support system (DSS) for the THSP in the various contexts referred to above, which is capable of accommodating the e ects of extra-ordinary environmental conditions, as well as the introduction of a computer-implemented version of a real DSS for the THSP conforming to the framework of this generic architecture. The DSS building blocks include prediction models for sugarcane yield, sugarcane recoverable value under normal circumstances, the costs associated with a harvesting schedule and the negative e ects on sugarcane recoverable value of extraordinary environmental conditions. The working of the DSS is based on a combinatorial optimisation model resembling the well-known asymmetric traveling salesman problem with time-dependent costs which is solved approximately by means of an attribute-based tabu search in which both local and global moves have been incorporated. The DSS is also validated by experienced sugarcane industry experts in terms of the practicality and quality of the schedules that it produces.
AFRIKAANSE OPSOMMING: Gerekenariseerde besluitsteun vir die skedulering van suikerriet-oeste is 'n aktiewe navorsingsveld wat nou verwant is aan die bre ër probleem van die outomatisering en vaartbelyning van 'n verskeidenheid aktiwiteite in die suikervoorsieningsketting. Die probleem van die daarstelling van steun rakende suikkerriet oestingsbesluite word in hierdie proefskrif in 'n aantal kontekste oorweeg, elk met betrekking tot 'n tipiese soort organisasie van suikerrietboere in 'n samehorige besluitnemingseenheid met sy spesi eke vereistes en beperkings in die praktyk. Verskeie variasies van 'n oorkoepelende taktiese suikerriet-oesskeduleringsprobleem (TSOSP) wat in hierde kontekste relevant is, naamlik die probleem om objektiewe, verantwoordbare steun aan besluitnemers te bied wat verantwoordelik is vir die bepaling van optimale oesdatums vir 'n versameling suikerrietplantasies oor die bestek van 'n hele seisoen, word in hierdie proefskrif bestudeer en opgelos. Suikerrietplantasies verskil tipies in terme van ouderdom, gewastipe, posisie in die lewensiklus, en vele ander eienskappe van die suikerriet wat daar groei. Omgewingstoestande, soos onbeplande brande, ryp of storms, het verder ook 'n negatiewe impak op die waarde van suikerriet op sulke plantasies. Omdat suikerriet 'n lewende organisme is, verander die eienskappe daarvan oor tyd, en so ook die potensi ele wins wat daarmee geassosieer word. Boerderypraktyke bemoeilik verder die skeduleringsprobleem onder beskouing (seisoenale veranderings beïnvloed byvoorbeeld die wyse waarop suikerriet ge-oes en vervoer word). Addisionele koste gaan voorts met die re ënseisoen gepaard, omdat die plantasies dan nie toeganklik is vir langafstand transportvoertuie nie en suikerriet gevolglik na spesiale laaisones gekarwei moet word voordat dit op hierdie voertuie gelaai kan word. Ander oorwegings, soos die vroe ë uitploeg van plantasies sodat die grond kan rus voordat nuwe suikerriet aangeplant word, veroorsaak dat die TSOSP 'n moeilike multi-faset probleem is, wat goeie databestuur, wiskundige modelleringsvernuf en doeltreff ende rekenaarwerk vereis. Die TSOSP word in die literatuur vanuit verskillende standpunte en in verskeie kontekste oorweeg, en 'n aantal uiteenlopende operasionele navorsingsmetodologie ë is al ingespan om hierdie probleem ten dele op te los. Daar is egter geen poging in die literatuur om 'n oplossing vir die TSOSP daar te stel waarin daar op 'n wetenskaplik-verantwoordbare wyse voorsiening gemaak word vir die negatiewe e ffekte wat uitsonderlike omgewingstoestande op die kwaliteit van oesskedules het nie; die meeste modelle in die literatuure is op slegs sukrose-opbrengs onder normale omstandighede gebaseer, wat lei na swak skedules in die praktyk. Die bestek van die wiskundige modellerings- en gepaardgaande oplossings-metodologie ë word in hierdie proefskrif vir die TSOSP beperk tot onderskeidelik heeltallige programmeringsformulerings en die bepaling van benaderde oplossings deur lokale soekprosedures. Die parameters wat met hierdie modelle en soekmetodes geassosieer word, word empiries bepaal deur gebruikmaking van historiese data asook bestaande werk oor die degradering van suikerriet as gevolg van omgewings- en ander eksterne faktore. Die TSOSP word in hierdie proefskrif opgelos deur die ontwerp van 'n generiese argitektuur vir 'n konseptuele besluitsteunstelsel (BSS) vir die TSOSP in die onderskeie kontekste waarna hierbo verwys word en wat die e ekte van uitsonderlike omgewingsfaktore in ag neem, asook die daarstelling van 'n rekenaar-ge ïmplementeerde weergawe van 'n daadwerklike BSS vir die TSOSP wat in die raamwerk van hierdie generiese argitektuur pas. Die boustene van hierdie BSS sluit modelle in vir die voorspelling van suikerrietopbrengs, die herwinbare waarde van suikerriet onder normale omstandighede, die verwagte koste geassosieer met 'n oesskedule en die negatiewe e ekte van omgewingsfaktore op die herwinbare waarde van suikerriet. Die werking van die BSS is gebaseer op 'n kombinatoriese optimeringsprobleem wat aan die welbekende asimmetriese handelreisigersprobleem met tyd-afhanklike kostes herinner, en hierdie model word benaderd opgelos deur middel van 'n eienskap-gebaseerde tabu-soektog waarin beide lokale en globale skuiwe ge ïnkorporeer is. Die BSS word ook gevalideer in terme van die haalbaarheid en kwaliteit van die skedules wat dit oplewer, soos geassesseer deur ervare kundiges in die suikerrietbedryf.

Thesis (MScEng (Process Engineering))--University of Stellenbosch, 2010.
ENGLISH ABSTRACT: The world’s depleting fossil fuels and increasing greenhouse gas emissions have given rise to much research into renewable and cleaner energy. Biomass is unique in providing the only renewable source of fixed carbon. Agricultural residues such as Sugarcane Bagasse (SB) are feedstocks for ‘second generation fuels’ which means they do not compete with production of food crops. In South Africa approximately 6 million tons of raw SB is produced annually, most of which is combusted onsite for steam generation. In light of the current interest in bio-fuels and the poor utilization of SB as energy product in the sugar industry, alternative energy recovery processes should be investigated. This study looks into the thermochemical upgrading of SB by means of pyrolysis. Biomass pyrolysis is defined as the thermo-chemical decomposition of organic materials in the absence of oxygen or other reactants. Slow Pyrolysis (SP), Vacuum Pyrolysis (VP), and Fast Pyrolysis (FP) are studied in this thesis. Varying amounts of char and bio-oil are produced by the different processes, which both provide advantages to the sugar industry. Char can be combusted or gasified as an energy-dense fuel, used as bio-char fertilizer, or upgraded to activated carbon. High quality bio-oil can be combusted or gasified as a liquid energy-dense fuel, can be used as a chemical feedstock, and shows potential for upgrading to transport fuel quality. FP is the most modern of the pyrolysis technologies and is focused on oil production. In order to investigate this process a 1 kg/h FP unit was designed, constructed and commissioned. The new unit was tested and compared to two different FP processes at Forschungszentrum Karlsruhe (FZK) in Germany. As a means of investigating the devolatilization behaviour of SB a Thermogravimetric Analysis (TGA) study was conducted. To investigate the quality of products that can be obtained an experimental study was done on SP, VP, and FP. Three distinct mass loss stages were identified from TGA. The first stage, 25 to 110°C, is due to evaporation of moisture. Pyrolitic devolatilization was shown to start at 230°C. The final stage occurs at temperatures above 370°C and is associated with the cracking of heavier bonds and char formation. The optimal decomposition temperatures for hemicellulose and cellulose were identified as 290°C and 345°C, respectively. Lignin was found to decompose over the entire temperature range without a distinct peak. These results were confirmed by a previous study on TGA of bagasse. SP and VP of bagasse were studied in the same reactor to allow for accurate comparison. Both these processes were conducted at low heating rates (20°C/min) and were therefore focused on char production. Slow pyrolysis produced the highest char yield, and char calorific value. Vacuum pyrolysis produced the highest BET surface area chars (>300 m2/g) and bio-oil that contained significantly less water compared to SP bio-oil. The short vapour residence time in the VP process improved the quality of liquids. The mechanism for pore formation is improved at low pressure, thereby producing higher surface area chars. A trade-off exists between the yield of char and the quality thereof. FP at Stellenbosch University produced liquid yields up to 65 ± 3 wt% at the established optimal temperature of 500°C. The properties of the bio-oil from the newly designed unit compared well to bio-oil from the units at FZK. The char properties showed some variation for the different FP processes. At the optimal FP conditions 20 wt% extra bio-oil is produced compared to SP and VP. The FP bio-oil contained 20 wt% water and the calorific value was estimated at 18 ± 1 MJ/kg. The energy per volume of FP bio-oil was estimated to be at least 11 times more than dry SB. FP was found to be the most effective process for producing a single product with over 60% of the original biomass energy. The optimal productions of either high quality bio-oil or high surface area char were found to be application dependent.
AFRIKAANSE OPSOMMING: As gevolg van die uitputting van fossielbrandstofreserwes, en die toenemende vrystelling van kweekhuisgasse word daar tans wêreldwyd baie navorsing op hernubare en skoner energie gedoen. Biomassa is uniek as die enigste bron van hernubare vaste koolstof. Landbouafval soos Suikerriet Bagasse (SB) is grondstowwe vir ‘tweede generasie bio-brandstowwe’ wat nie die mark van voedselgewasse direk affekteer nie. In Suid Afrika word jaarliks ongeveer 6 miljoen ton SB geproduseer, waarvan die meeste by die suikermeulens verbrand word om stoom te genereer. Weens die huidige belangstelling in bio-brandstowwe en ondoeltreffende benutting van SB as energieproduk in die suikerindustrie moet alternatiewe energie-onginningsprosesse ondersoek word. Hierdie studie is op die termo-chemiese verwerking van SB deur middel van pirolise gefokus. Biomassa pirolise word gedefinieer as die termo-chemiese afbreking van organiese bio-materiaal in die afwesigheid van suurstof en ander reagense. Stadige Pirolise (SP), Vakuum Pirolise (VP), en Vinnige Pirolise word in hierdie tesis ondersoek. Die drie prosesse produseer veskillende hoeveelhede houtskool en bio-olie wat albei voordele bied vir die suikerindustrie. Houtskool kan as ‘n vaste energie-digte brandstof verbrand of vergas word, as bio-houtskoolkompos gebruik word, of kan verder tot geaktiveerde koolstof geprosesseer word. Hoë kwaliteit bio-olie kan verbrand of vergas word, kan as bron vir chemikalië gebruik word, en toon potensiaal om in die toekoms opgegradeer te kan word tot vervoerbrandstof kwaliteit. Vinnige pirolise is die mees moderne pirolise tegnologie en is op bio-olie produksie gefokus. Om die laasgenoemde proses te toets is ‘n 1 kg/h vinnige pirolise eenheid ontwerp, opgerig en in werking gestel. Die nuwe pirolise eenheid is getoets en vegelyk met twee verskillende vinnige pirolise eenhede by Forschungszentrum Karlsruhe (FZK) in Duitsland. Termo-Gravimetriese Analise (TGA) is gedoen om die ontvlugtigingskenmerke van SB te bestudeer. Eksperimentele werk is verrig om die kwaliteit van produkte van SP, VP, vinnige pirolise te vergelyk. Drie duidelike massaverlies fases van TGA is geïdentifiseer. Die eerste fase (25 – 110°C) is as gevolg van die verdamping van vog. Pirolitiese ontvlugtiging het begin by 230°C. Die finale fase (> 370°C) is met die kraking van swaar verbindings en die vorming van houtskool geassosieer. Die optimale afbrekingstemperatuur vir hemisellulose en sellulose is as 290°C en 345°C, respektiewelik, geïdentifiseer. Daar is gevind dat lignien stadig oor die twede en derde fases afgebreek word sonder ‘n duidelike optimale afbrekingstemperatuur. Die resultate is deur vorige navorsing op TGA van SB bevestig. SP en VP van bagasse is in dieselfde reaktor bestudeer, om ‘n akkurate vergelyking moontlik te maak. Beide prosesse was by lae verhittingstempo’s (20°C/min) ondersoek, wat gevolglik op houtskoolformasie gefokus is. SP het die hoogste houtskoolopbrengs, met die hoogste verbrandingsenergie, geproduseer. VP het hootskool met die hoogste BET oppervlakarea geproduseer, en die bio-olie was weens ‘n dramatiese afname in waterinhoud van beter gehalte. Die meganisme vir die vorming van ‘n poreuse struktuur word deur lae atmosferiese druk verbeter. Daar bestaan ‘n inverse verband tussen die kwantiteit en kwaliteit van die houtskool. Vinnige pirolise by die Universiteit van Stellenbosch het ‘n bio-olie opbrengs van 65 ± 3 massa% by ‘n vooraf vasgestelde optimale temperatuur van 500°C geproduseer. Die eienskappe van bio-olie wat deur die nuwe vinnige pirolise eenheid geproduseer is het goed ooreengestem met die bio-olie afkomstig van FZK se pirolise eenhede. Die houtskool eienskappe van die drie pirolise eenhede het enkele verskille getoon. By optimale toestande vir vinnige pirolise word daar 20 massa% meer bio-olie as by SP en VP geproduseer. Vinnige pirolise bio-olie het ‘n waterinhoud van 20 massa% en ‘n verbrandingswarmte van 18 ± 1 MJ/kg. Daar is gevind dat ten opsigte van droë SB die energie per enheidsvolume van bio-olie ongeveer 11 keer meer is. Vinnige pirolise is die mees doeltreffende proses vir die vervaardiging van ‘n produk wat meer as 60% van die oorspronklike biomassa energie bevat. Daar is gevind dat die optimale hoeveelhede van hoë kwaliteit bio-olie en hoë oppervlakarea houtskool doelafhanklik is.

The research presented in this thesis was developed as part of DIBANET, an EC funded project aiming to develop an energetically self-sustainable process for the production of diesel miscible biofuels (i.e. ethyl levulinate) via acid hydrolysis of selected biomass feedstocks. Three thermal conversion technologies, pyrolysis, gasification and combustion, were evaluated in the present work with the aim of recovering the energy stored in the acid hydrolysis solid residue (AHR). Mainly consisting of lignin and humins, the AHR can contain up to 80% of the energy in the original feedstock. Pyrolysis of AHR proved unsatisfactory, so attention focussed on gasification and combustion with the aim of producing heat and/or power to supply the energy demanded by the ethyl levulinate production process. A thermal processing rig consisting on a Laminar Entrained Flow Reactor (LEFR) equipped with solid and liquid collection and online gas analysis systems was designed and built to explore pyrolysis, gasification and air-blown combustion of AHR. Maximum liquid yield for pyrolysis of AHR was 30wt% with volatile conversion of 80%. Gas yield for AHR gasification was 78wt%, with 8wt% tar yields and conversion of volatiles close to 100%. 90wt% of the AHR was transformed into gas by combustion, with volatile conversions above 90%. 5volO2%-95vol%N2 gasification resulted in a nitrogen diluted, low heating value gas (2MJ/m3). Steam and oxygen-blown gasification of AHR were additionally investigated in a batch gasifier at KTH in Sweden. Steam promoted the formation of hydrogen (25vol%) and methane (14vol%) improving the gas heating value to 10MJ/m3, below the typical for steam gasification due to equipment limitations. Arrhenius kinetic parameters were calculated using data collected with the LEFR to provide reaction rate information for process design and optimisation. Activation energy (EA) and pre-exponential factor (ko in s-1) for pyrolysis (EA=80kJ/mol, lnko=14), gasification (EA=69kJ/mol, lnko=13) and combustion (EA=42kJ/mol, lnko=8) were calculated after linearly fitting the data using the random pore model. Kinetic parameters for pyrolysis and combustion were also determined by dynamic thermogravimetric analysis (TGA), including studies of the original biomass feedstocks for comparison. Results obtained by differential and integral isoconversional methods for activation energy determination were compared. Activation energy calculated by the Vyazovkin method was 103-204kJ/mol for pyrolysis of untreated feedstocks and 185-387kJ/mol for AHRs. Combustion activation energy was 138-163kJ/mol for biomass and 119-158 for AHRs. The non-linear least squares method was used to determine reaction model and pre-exponential factor. Pyrolysis and combustion of biomass were best modelled by a combination of third order reaction and 3 dimensional diffusion models, while AHR decomposed following the third order reaction for pyrolysis and the 3 dimensional diffusion for combustion.

Sugarcane is a major crop in many countries. It is the most abundant lignocellulosic material in tropical countries such as South Africa. It is one of the plants with the highest bioconversion efficiency. The sugarcane crop is able to efficiently fix solar energy, yielding some 55 tons of dry matter per hectare of land annually. After harvest, the crop produces sugar juice and bagasse. Sugarcane bagasse is a residue that results from the crushing of sugarcane in the sugar industry. It is a renewable feedstock that can be used for power generation and manufacturing cellulosic ethanol. As biomass, sugarcane bagasse holds promise as a fuel source since it can produce more than enough electricity and heat energy to supply the needs of a common sugar factory. However, in the sugarcane industry the bagasse is currently burnt inefficiently in boilers that provide the heating for the industry. This project seeks to investigate the possibility of gasifying sugarcane bagasse as an efficient conversion technology. The investigation is necessary because fuel properties govern the gasifier design and ultimately, the gasification efficiency. Proximate and ultimate analysis of sugarcane bagasse was conducted after which the results were used to conduct a computer simulation of the mass and energy balance during gasification. The kinetic investigation undertaken through the TGA and DTG analyses revealed the activation energy and pre – exponential factor which were obtained by the model – free Kissinger method of kinetic analysis and were found to be 181.51 kJ/mol and 3.1 × 103/min respectively. The heating value of sugarcane bagasse was also measured and found to be 17.8 MJ/kg, which was used in the calculation of the conversion efficiency of the gasification process. Fuel properties, including moisture content and gasifier operating parameters were varied in order to determine optimum gasifier operating conditions that results in maximum conversion efficiency. The highest conversion efficiency was achieved at low moisture content after computer simulation of the gasification process. Moisture content also affected the volume of CO and H2 as the former decreases with increasing moisture content while the latter increases with increasing moisture content, accelerating the water – gas reaction. Scanning electron microscope fitted to an Energy dispersive X – ray spectroscopy was also used in order to view the shape and size distribution as well as determine the elemental composition of sugarcane bagasse. The results obtained established that the fuel properties and gasification conditions affect the conversion efficiency. During computer simulation, it was established that smaller particle size resulted in higher conversion efficiency. The smaller throat diameter also resulted in higher conversion efficiency. The throat angle of 25° also resulted in higher conversion efficiency. The temperature of input air was also found to be one of the major determining factors in terms of conversion efficiency. The dissertation presents the proximate and ultimate analysis results as well as the kinetic analysis results. The SEM/EDX analysis as well as the computer simulation results of the gasification process is also presented. The major contribution of this project was on the investigation of the gasification characteristics of sugarcane bagasse and the utilization of these in the design of a laboratory scale sugarcane bagasse gasifier with enhanced conversion efficiency through computer simulation.

Thesis (PhD)--Stellenbosch University, 2014.
ENGLISH ABSTRACT: Increased demand of petroleum, declining fossil fuel reserves, geopolitical instability and the environmentally detrimental effects of fossil fuels have stimulated research to search for alternative sources of energy such as plant derived biofuels. The main feedstocks for production of first generation biofuels (bioethanol) are currently sucrose and starch, produced by crops such as sugarcane, sugarbeet, maize, and cassava. The use of food crop carbohydrates to produce biofuels is viewed as competing for limited agronomic resources and jeopardizing food security. Plants are also capable of storing sugars in their cell walls in the form of polysaccharides such as cellulose, hemicelluloses and pectin, however those are usually cross-linked with lignin, making their fermentation problematic, and are consequently referred to as lignocellulosics. Current technologies are not sufficient to degrade these cell wall sugars without large energy inputs, therefore making lignocellulosic biomass commercially unviable as a source of sugars for biofuel production. In the present study genes encoding for enzymes for cellulosic, hemicellulosic and starch-like polysaccharides biosynthesis were heterologously expressed to increase the amount of fermentable sugars in sugarcane. Transgenic lines heterologously expressing CsCesA, encoding a cellulose synthase from the marine invertebrate Ciona savignyi showed significant increases in their total cellulose synthase enzyme activity as well as the total cellulose content in internodal tissues. Elevation in cellulose contents was accompanied by a rise in hemicellulosic glucose content and uronic acid amounts, while total lignin was reduced in internodal tissues. Enzymatic saccharification of untreated lignocellulosic biomass of transgenic sugarcane lines had improved glucose release when exposed to cellulose hydrolyzing enzymes. Calli derived from transgenic sugarcane lines ectopically expressing galactomannan biosynthetic sequences ManS and GMGT from the cluster bean (Cyamopsis tetragonoloba) were observed to be capable of producing a galactomannan polysaccharide. However, after regeneration, transgenic sugarcane plants derived from those calli were unable to produce the polymer although the inserted genes were transcribed at the mRNA level. While the ectopic expression of Deinococcus radiodurans amylosucrase protein in the cytosol had a detrimental effect on the growth of transgenic lines (plants showed stunted growth through the 18 months growth period in greenhouse), contrastingly targeting the amylosucrase protein into the vacuole resulted in 3 months old transgenic lines which were having high maltooligosaccharide and soluble sugar (sucrose, glucose and fructose) levels in leaves. After 18 months growing in the greenhouse, the mature transgenic lines were morphologically similar to the untransformed lines and also contained comparable maltooligosaccharide and soluble sugar and starch amounts. The non-biosynthesis of galactomannan and amylose polysaccharides in the matured transgenic plants may be due to post-transcriptional protein processing and or protein instability, possibly explainable by other epigenetic mechanisms taking place to regulate gene expression in the at least allo-octaploid species of sugarcane under investigation in this study.

Lignocellulosic biomasses are an important source of chemical components such as cellulose, lignin and hemicelluloses, and can be used for a variety of purposes in both the pulp and paper and chemical conversion industries. Xylan, the main hemicellulose found in hardwood and grass plants, plays an important role during the pulping/pretreatment process reactions, including those used in 2nd generation bioethanol production. It may also play an important role in the production of certain novel materials. This thesis evaluates the composition of eucalyptus (Eucalyptus urophylla x Eucalyptus grandis), sugarcane bagasse and sugarcane straw, with a specific focus on the structure and properties of xylan. The chemical characterization of biomasses showed that sugarcane bagasse and straw contain larger amounts of extractives, ash and silica than eucalyptus. The large amount of silica leads to an overestimation of the Klason lignin content, if not corrected. By using a complete mass balance approach, sugarcane bagasse and straw were shown to contain smaller amounts of lignin (18.0% and 13.9%, respectively) than previously reported for these raw materials, and certainly a much smaller amount of lignin than was found in eucalyptus (27.4%). The hemicellulose content in sugarcane bagasse (28.7%) and straw (29.8%) was much higher than that in eucalyptus (20.3%). In order to investigate the structure of the xylan in greater detail, it was extracted with dimethyl sulfoxide from holocellulose, obtained by either peracetic acid or sodium chlorite delignification. The structure of the isolated xylans was confirmed by FTIR and 1H NMR analysis. In eucalyptus, the O-acetyl-(4-O-methylglucurono)xylan (MGX) was identified. This had a molar ratio of xylose units to branches of 4-O-methylglucuronic acid of 10:1.1 and a degree of acetylation of 0.39. All 4-O- methylglucuronic acid groups were attached to position O-2 of the xylose units, which had an acetyl group in position O-3. The acetyl groups were distributed in positions O-3 (64%), O-2 (26%) and O-2,3 (10%). The MGX had a molecular weight (Mw) of about 42 kDa. In bagasse and straw, arabinoxylan (AX) was identified. This had a molar ratio of xylose units to arabinosyl substitutions of 10:0.5 for bagasse and 10:0.6 for straw. A degree of acetylation was 0.29 and 0.08 for bagasse and straw, respectively. The arabinose units were attached preferentially to position O-3 in AX. In the xylan from bagasse, the acetyl groups were found in positions O-3 (60%), O-2 (13%) and O-2,3 (27%), while in the xylan from straw, the acetyl groups were distributed between positions O-3 (67%) and O-2 (33%). The AX had a molecular weight (Mw) of about 38 kDa and 30 kDa for bagasse and straw, respectively. The differences in the structure of xylan present in the various biomasses played an important role during hydrothermal pretreatment, which is often used as the first step in 2nd generation ethanol production. The varying amounts of uronic acid and acetyl groups resulted in different starting pH levels of liquor and, thus, affected the chemical transformation in the biomasses in different ways. The hydrothermal pretreatment resulted mostly in the removal and/or transformation of hemicelluloses, but also in the formation of a significant number of pseudo-lignin structures. In addition, in eucalyptus, pseudo-extractives structures were generated. The sugarcane straw showed the highest mass loss during the investigated pretreatment.

QC 20151023

Submitted by Marco Antônio de Ramos Chagas (mchagas@ufv.br) on 2016-08-25T17:49:22Z No. of bitstreams: 1 texto completo.pdf: 4509982 bytes, checksum: 1ddc3e8d6d2fd98d0186c187ff37a974 (MD5)
Made available in DSpace on 2016-08-25T17:49:22Z (GMT). No. of bitstreams: 1 texto completo.pdf: 4509982 bytes, checksum: 1ddc3e8d6d2fd98d0186c187ff37a974 (MD5) Previous issue date: 2016-02-22
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
O etanol tem sido considerado um promissor biocombustível para substituir combustíveis fósseis. O uso estratégico de eucalipto, bagaço e palha de cana-de-açúcar em tecnologias de segunda geração para a produção de etanol foi estudada neste trabalho, usando vários processos de pré-tratamentos seguidos por sacarificação e fermentação simultâneas (SFS). No artigo I é apresentada a caracterização química de eucalipto, bagaço e palha de cana-de-açúcar antes e após os pré-tratamentos hidrotérmico (H 2 O), ácido diluído (4,5% H 2 SO 4 ) e alcalino (15% NaOH). Foi determinado que o significativo teor de sílica presente em bagaço e palha da cana-de- açúcar causaram superestimação da lignina Klason nessas biomassas. O novo método para reportar a composição química das biomassas, baseado no completo balanço de massas, foi sugerido e provou ser útil para avaliar ambas, matéria-prima e biomassa pré- tratada. A formação de pseudo-extrativos na madeira de eucalipto e pseudo-lignina no bagaço e na palha foi observada como resultado dos pré-tratamentos. O Artigo II apresenta a caracterização química e estrutural das xilanas isoladas a partir de eucalipto, bagaço e palha usando dois métodos, sendo eles: deslignificação com ácido peracético seguida por extração com dimetilsulfóxido e deslignificação com clorito de sódio seguida por extração com dimetilsulfóxido. A xilana obtida a partir do eucalipto foi identificada como do tipo O-acetil-4-O-metilglucuronoxilana, contendo 39 unidades de grupos acetilas e 11 ácidos 4-O-metilglucurônicos para cada 100 unidades de xilose na cadeia principal. Além disso, um ácido 4-O-metilglucurônico foi também substituído por uma unidade de galactosil terminal. A xilana obtida a partir de bagaço e palha foi do tipo arabinoxilana, que apresentou proporcionalmente 100 unidades de xiloses: 29 unidades de grupos acetilas: 5 unidades de arabinofuranosil para o bagaço e proporcionalmente 100 unidades de xiloses: 8 unidades de grupos acetilas: 6 unidades de arabinofuranosil para a palha. O Artigo III descreve o efeito dos pré-tratamentos hidrotérmico e ácido diluído (1,5%, 3,0% e 4,5% de H 2 SO 4 ) na composição química das biomassas e sua subsequente conversão em etanol. Observou-se que a redução no pH dos pré-tratamentos favoreceu a remoção de lignina e carboidratos. O eucalipto apresentou a maior produção de etanol após o pré-tratamento hidrotérmico, mas com rendimento relativamente baixo. Após os pré-tratamentos ácidos, bagaço e palha mostraram maiores produções de etanol que o eucalipto. O pré-tratamentos realizados com 4,5% de H 2 SO 4 foi o mais eficiente. O Artigo IV avalia o efeito da carga alcalina durante os pré-tratamentos alcalinos (5%, 10% e 15% NaOH) na composição química das biomassas e sua subsequente conversão em etanol. Observou-se que as maiores cargas alcalinas propiciaram as maiores remoções de lignina e carboidratos. Para pré- tratamentos alcalinos, o bagaço provou ser a biomassas mais promissora para produção de etanol. O pré-tratamento com 15% de NaOH foi o mais eficiente. O Artigo V apresenta a otimização do pré-tratamento de extração alcalina a frio (EAF) referente à temperatura (20oC, 30oC e 40oC), tempo de reação (10, 35 e 60 min.) e concentração de NaOH (70, 90 e 110 g L -1 ) com foco na remoção de xilanas das biomassas e subsequente conversão das biomassas deficientes em xilanas em etanol. As condições ótimas para a remoção de xilanas de madeira de eucalipto, bagaço e palha da cana-de- açúcar foram respectivamente: 40oC, 60 min. e 70 g L -1 de NaOH; 33oC, 60 min. e 110 g L -1 de NaOH; e 31oC, 55 min. e 110 g L -1 de NaOH. Nessas condições de pré- tratamentos, considerável quantidade de lignina também foi removida das biomassas. Para a madeira de eucalipto, a formação de pseudo-extrativos foi observada durante os pré-tratamentos de EAF. A palha da cana-de-açúcar pré-tratada por EAF foi a biomassa mais promissora para a produção de etanol de segunda geração. Para os pré-tratamentos de EAF, os maiores rendimentos em etanol foram obtidos para bagaço e palha da cana- de-açúcar que para a madeira de eucalipto. Em resumo, os resultados acumulados por essa tese de doutorado sugeriram que bagaço e palha são biomassas aplicáveis à produção de etanol de segunda geração. O uso dessas biomassas lignocelulósicas cria a possibilidade de integrar primeira e segunda plataformas para a produção de etanol, transformando resíduo em produto principal.
The ethanol has been considered a promising biofuel to replace fossil-based fuels. The strategic use of eucalyptus, sugarcane bagasse and sugarcane straw in second generation technology to ethanol production was investigated in this work, by performing various pretreatment processes followed by simultaneous saccharification and fermentation (SSF). In article I it is presented the chemical characterization of eucalyptus, sugarcane bagasse and straw before and after hydrothermal (H 2 O), diluted acid (4.5% H 2 SO 4 ) and alkaline (15% NaOH) pretreatments. It was determined that the significant amount of silica present in sugarcane bagasse and straw led to overestimation of Klason lignin of these biomasses. A novel approach to report the chemical composition of biomasses, based on the complete mass balance, was suggested and proved to be useful to assess both, raw materials and pretreated biomasses. The formation of pseudo-extractives in eucalyptus wood and pseudo-lignin in bagasse and straw as result of pretreatments was observed. Article II presents the chemical and structural characterization of xylans isolated from eucalyptus, bagasse and straw via two different methods, namely: peracetic acid delignification followed by dimethyl sulfoxide extraction and sodium chlorite delignification followed by dimethyl sulfoxide extraction. The xylan obtained from eucalyptus was identified as an O-acetyl-4-O-methylglucuronoxylan type, containing 39 acetyl groups units and 11 4-O-methylglucuronic acids per 100 units of xylose on the backbone. In addition, one 4-O-methylglucuronic acid was also substituted by one terminal galactosyl unit. The xylan obtained from bagasse and straw was an arabinoxylan type, which contained 100 xylose units: 29 acetyl groups units: 5 arabinofuranosyl units for bagasse, proporcionally, and 100 xylose units: 8 acetyl groups units: 6 arabinofuranosyl units for straw, proporcionally. Article III describes the effect of hydrothermal and diluted acid (1.5, 3.0 and 4.5% H 2 SO 4 ) pretreatments on the chemical composition of biomasses and their subsequent conversion into ethanol. It was observed that lowering pretreatment pH resulted in improved lignin and carbohydrates removal. The eucalyptus presented the highest ethanol production after hydrothermal pretreatment, but with relative low yield. After acid pretreatments, bagasse and straw showed higher ethanol productions then eucalyptus. The pretreatment performed at 4.5% H 2 SO 4 was the most efficient. Article IV assesses the effect of alkaline charge during alkaline (5, 10 and 15% NaOH) pretreatments on the chemical composition of biomasses and their subsequent conversion into ethanol. It was observed that higher alkaline charge provided the highest lignin and carbohydrates removal. For the alkaline pretreatments, the bagasse proved to be the most promising biomass for ethanol production. The pretreatment with 15% NaOH was the most efficient. Article V presents an optimization of the cold alkaline extraction (CAE) pretreatment regarding temperature (20oC, 30oC and 40oC), reaction time (10, 35 and 60 min) and NaOH concentration (70, 90 and 110 g L -1 ), focusing on xylan removal from biomasses and subsequent conversion of the xylan-depleted biomasses into ethanol. The optimal conditions for xylan removal from eucalyptus wood, sugarcane bagasse and sugarcane straw were, respectively: 40oC, 60 min and 70 g L -1 NaOH; 33oC, 60 min and 110 g L -1 NaOH; and 31oC, 55 min and 110 g L -1 NaOH. Under these pretreatments conditions, substantial amounts of lignin were also removed from the biomasses. For the eucalyptus wood, the formation of pseudo-extractives was observed during the CAE pretreatments. The sugarcane straw pretreated with CAE was the most promising biomass for production of second generation ethanol. For the CAE pretreatments, higher ethanol yields were achieved with sugarcane bagasse and straw in relation to eucalyptus wood. In summary, the results accumulated from this doctoral thesis suggested that bagasse and straw are suitable biomasses for production of second generation ethanol. The use of these lignocellulosic biomasses creates the possibility of integrating first and second platforms for ethanol production, which turns residues into main product.

Thesis (PhD (Genetics. Plant Biotechnology))--University of Stellenbosch, 2005.
The current understanding of the regulation of sucrose accumulation is still incomplete even though many scientists have investigated this subject. Components of trehalose metabolism have been implicated in the regulation of carbon flux in bacteria, yeast and more recently in plants. With a view to placing trehalose metabolism in the context of cytosolic sugarcane sucrose metabolism and carbon partitioning we have investigated the metabolites, transcripts and enzymes involved in this branch of carbohydrate metabolism in sugarcane internodal tissues. Sugarcane internodal trehalose levels varied between 0.31 ± 0.09 and 3.91 ± 0.99 nmol.g-1 fresh weight (FW). From statistical analysis of the metabolite profile it would appear that trehalose does not directly affect sucrose accumulation, although this does not preclude involvement of trehalose- 6-phosphate in the regulation of carbon partitioning. The metabolite data generated in this study demanded further investigation into the enzymes (and their transcripts) responsible for trehalose metabolism. Trehalose is synthesised in a two step process by the enzymes trehalose-6-phosphate synthase (EC 2.4.1.15, TPS) and trehalose-6-phosphate phosphatase (EC 3.1.3.12, TPP), and degraded by trehalase (EC 3.2.1.28). Two novel sugarcane partial cDNAs that coded for trehalase (tre) and actin (required for normalisation in profiling experiments) were isolated and used along with partial transcripts for TPS and TPP to determine transcript levels in different tissue- and genotypes. A putative full-length SugTPS cDNA was isolated and characterised. Enzyme activities for TPS, TPP and trehalase were measured at levels of 2.7 nmol.min-1.mg-1protein, 8.5 nmol.min-1.mg-1protein and 6.2 nmol.min-1.mg-1protein respectively, from young internodal protein extracts of sugarcane, variety N19. TPP enzyme activity and transcript levels were higher in S. spontaneum than Saccharum interspecific hybrids. Kinetic analysis of TPP and trehalase activities were performed with the purpose of providing parameters for an in silico kinetic model of trehalose and sucrose metabolism. Three isoforms of TPP were identified and desingated TPPAI, TPPAII and TPPB. Both TPPA isoforms had pH optima of 6.0, and TPPB of pH 6.5. Apparent Km values were determined as 0.447 ± 0.007 mM for TPPAI, 13.82 ± 1.98 mM for TPPAII and 1.387 ± 0.18 mM for TPPB. Partial purification and characterisation of trehalase demonstrated dual pH optima of 3.5 and 6.0, with Km values between 0.345 and 0.375 mM. These data were used as the basis for a kinetic model of trehalose metabolism. A previously described kinetic model of cytosolic sucrose metabolism has been expanded to include the trehalose pathway (TPS, TPP and trehalase). The aim was to supplement the available information on cytosolic metabolism in sugarcane storage parenchyma, identify points of control between sucrose and trehalose metabolism, and provide a platform from which further experimental and in silico modelling can be launched. The model predicted trehalose in the same order of magnitude as those determined in the metabolite profiling experiments. The majority of control of flux over the trehalose pathway resided in the TPS step, with flux control coefficients > 70% of the total pathway. Incorporation of the trehalose branch into the original sucrose model showed that reactions from the original model significantly affected the steady-state attributes of the trehalose pathway. Due to the relatively low flux through the trehalose branch of the expanded model, complete recycling of trehalose, and the lack of allosteric regulation by trehalose-6-phosphate or trehalose on any of the reactions from the original sucrose model, incorporation of the trehalose branch had no significant effect on either steady-state cytosolic sucrose concentration or flux of sucrose into the vacuole. The expanded model affords a basis from which to further investigate trehalose metabolism in the context of plant sucrose accumulation.

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.
Includes bibliographical references (leaves 46-47).
In Haiti, most families have traditionally relied on wood and wood-derived charcoal as their primary fuel source for indoor cooking. This resource has proven to be unsustainable, however, as over 90% of the Haitian countryside has already been deforested and wood is now in low supply. As a poor country, importing fuel is not a viable option and thus, the ability to utilize renewable energy sources is critical. The work of the Edgerton Development Lab, under the guidance of Amy Smith, has developed a process utilizing an oil drum kiln to convert readily available agricultural waste from sugarcane, known as bagasse, into clean burning charcoal briquettes. In order to improve the efficiency of the existing oil drum kiln, this research will explore the design of a brick kiln that is relevant for the social dynamic of developing countries, inexpensive to manufacture and simple to operate. By defining the best system applicable to the Haitian context, this research will enable the efficient production of charcoal. This research will also define the shape of the chamber and the steps involved in the conversion process, enabling Haitians to make use of their natural resources to address a critical energy need. In addition, the enhanced energy efficiency will reduce the production time of the charcoal briquettes. Lastly, this research will explore how this technology can be best integrated into the existing culture and lifestyle of the Haitian community and propose a strategy for community participation.
by Etienne Clement Toussaint.
S.B.

Universidade Federal do CearÃ
The present work aimed at the production of lignosulfonate, based in the lignin extracted from sugarcane bagasse-cane for using in phenolic resins. The extraction of lignin was carried out using the acetosolv process, which was optimised with a central composite design 22 to evaluate the effects of reaction time and temperature on the extraction yield, weight-average (M ̅w) and number-average (M ̅n) molecular weights, relative content of total hydroxyl, phenolic hydroxyl and methoxyl groups. The lignins obtained under conditions that maximized the extraction yield and showed better structural and thermal characteristics were sulfonated to obtain the lignosulfonates. The structural and thermal characteristics of the lignins and lignosulfonates were determined by FT-IR, GPC, 1H-NMR and 13C-NMR, DSC and TGA. The results show that the best extraction yield (64.5%) was obtained with 95% (w/w) of acetic acid, the addition of 0.1% HCl, at a temperature of 187 ÂC and reaction time of 40 min. However, with the same concentration of acetic acid and reaction time of 15 min at 187 ÂC, the extraction yield decreased to 55.6% Â 4.5%, without significant reduction. Furthermore, the increase in temperature of 187 ÂC to 205 ÂC was not enough to cause a significant increase in the relative content of hydroxyls and reduction of the relative content of methoxyl. These results show that the most appropriate conditions for adequate extraction of lignin for application in resins are: 95% (w/w) of acetic acid, addition of 0.1% of HCl, temperature of 187 ÂC and reaction time of 15 min. The acetosolv lignins showed p-hidroxifenila units as major constituent, higher thermal stability and higher purity than the commercial Kraft lignin. The glass transition temperature of the Kraft lignins was lower than that of the acetosolv lignin. This is due to the hydrophilic character and the presence of carbohydrates in the Kraft lignin. The lignosulfonates obtained in this study showed structural characteristics suitable for application in phenolic resins, because they showed high reactivity due to the greater presence of p-hidroxifenila units as major constituent, low molecular weights (40234878 g/mol), greater stability and greater purity compared to commercial sodium lignosulfonate. Therefore, lignosulfonates obtained in this work are more suitable for use in phenolic resins than commercial sodium lignosulfonate used for comparison.
O presente trabalho teve por objetivo a produÃÃo de lignossulfonato, a partir da lignina extraÃda do bagaÃo da cana-de-aÃÃcar para aplicaÃÃo em resinas fenÃlicas. Foi realizada a otimizaÃÃo da extraÃÃo da lignina do bagaÃo de cana-de-aÃÃcar utilizando o processo acetosolv. Para tanto, empregou-se um delineamento composto central 22 para analisar os efeitos do tempo de reaÃÃo e da temperatura no rendimento de extraÃÃo, massa molar ponderal mÃdia, massa molar numÃrica mÃdia, e conteÃdo relativo de hidroxilas totais, hidroxilas fenÃlicas e metoxilas. As ligninas obtidas nas condiÃÃes que maximizaram o rendimento de extraÃÃo e que mostraram melhores caracterÃsticas estruturais e tÃrmicas foram sulfonadas para obtenÃÃo dos lignossulfonatos. As caracterÃsticas estruturais e tÃrmicas das ligninas e dos lignossulfonatos foram determinadas por FT-IR, GPC, RMN-1H e 13C, TGA e DSC. Os resultados mostram que o melhor rendimento de extraÃÃo (64,5 % 4,2%) foi obtido com 95% (m/m) de Ãcido acÃtico, adiÃÃo de 0,1% de HCl, a uma temperatura de 187 C e tempo de reaÃÃo de 40 min. No entanto, com a mesma concentraÃÃo de soluÃÃo de Ãcido acÃtico e com tempo de reaÃÃo de 15 min a 187ÂC, o rendimento de extraÃÃo diminuiu para 55,6%  4,5%, nÃo sendo significativa esta reduÃÃo. AlÃm disto, a elevaÃÃo da temperatura de 187ÂC para 205ÂC nÃo foi suficiente para causar um aumento significativo no conteÃdo relativo de hidroxilas e reduÃÃo do conteÃdo relativo de metoxila. Esses resultados mostram que as condiÃÃes mais adequadas para extraÃÃo da lignina a ser aplicada em resinas sÃo: 95% (m/m) de Ãcido acÃtico, adiÃÃo de 0,1% de HCl, temperatura de 187 C e tempo de reaÃÃo de 15 min. As ligninas acetosolv apresentaram unidades p-hidroxifenila como constituinte majoritÃrio, maior estabilidade tÃrmica e maior pureza em relaÃÃo à lignina Kraft comercial. A temperatura de transiÃÃo vÃtrea da lignina Kraft foi menor do que à das ligninas acetosolv, devido à sua caracterÃstica hidrofÃlica e à presenÃa de carboidratos na lignina Kraft. Os lignossulfonatos obtidos no presente trabalho apresentaram caracterÃsticas estruturais adequadas para aplicaÃÃo em resinas fenÃlicas, pois mostraram alta reatividade devido a maior presenÃa de unidades p-hidroxifenila como constituinte majoritÃrio, baixas massas molares (4023 a 4878 g/mol), maior estabilidade e uma maior pureza em relaÃÃo ao lignossulfonato de sÃdio comercial. Portanto, os lignossulfonatos obtidos no presente trabalho sÃo mais adequados para aplicaÃÃo em resinas fenÃlicas do que o lignossulfonato de sÃdio comercial utilizado no presente trabalho.

This study provides information to support the use of plant cell wall, from sugarcane bagasse, to produce cellulosic ethanol. Therewith, cell wall proteins from sugarcane cells cultures, leaves and culms were identified. To do so, different protocols were used. Using two-month-old leaves and culms, the extractions were performed using a destructive method, based on griding the tissues, submitting them to a growing gradient of succrose and centrifugation, being the cell wall extract later isolated by washing on a nylon net. After that, the cell wall proteins were extracted using two salts, 0,2 M CaCl2 and 2 M LiCl. Using cultured cells, a similar protocol was used, but it had a previous step of separation of the cell wall through grinding and precipitation in glycerol 15%. Using culms of the same age, a nondestructive protocol was tested based on vacuum infiltration of the tissues in the same salts already described, 0,2 M CaCl2 and 2 M LiCl, and posterior centrifugation. Two replicates were used from two-month-old plants and three in the case of suspension cells. The complex samples were digested, fractionated and sequenced through mass spectrometry, using SYNAPT G2HDMS coupled to nanoACQUITY, both from Waters. Peptides were processed using ProteinLynx 2.5 Global Server against sugarcane translated-EST database. Using bioinformatic programs, such as Blast2GO, it was possible to find the annotation and classification of similar proteins. Only proteins equally found in all repetitions were considered in the main analysis. SignalP, WolfPSORT, TargetP, TMHMM and Predotar were used to predict the subcellular location, both from ESTs and blasted proteins, and only the proteins predicted to be secreted in two or more programs were considered as cell wall proteins. Altogether, 157 different SAS related to sugarcane cell wall were found. Among these, 101 different cell wall proteins were characterized from eight functional classes. The method based on vacuum infiltration seems to be the most efficient one, since it had almost half, 48,84% of the proteins predicted to be secreted, which is a good percentage when comparing to other studies. From secreted proteins most of them were related to lipid metabolism, as lipid-transfer proteins, oxido-reductases, such as peroxidases, cell wall modifying enzymes, like glycoside-hydrolases, proteases, proteins with interacting domains, signaling proteins and several others. Results are in agreement with the expected role of the extracellular matrix in polysaccharide metabolism and signaling phenomena. Therefore, this work provided valuable information about sugarcane cell wall that can lead to future studies to enhance cellulosic ethanol production.
Este estudo fornece informação para auxiliar o uso da parede celular vegetal, a partir do bagaço de cana, para a produção de etanol celulósico. Com isso, as proteínas da parede celular de folhas, colmos e células em suspensão foram identificadas. Para isso, foram utilizados diferentes protocolos. Utilizando folhas e colmos de cana-de-açúcar de dois meses de idade, as extracções foram realizadas por meio de método destrutivo, com base na trituração dos tecidos, submetendo-os a gradiente crescente de sacarose e centrifugação, sendo a parede da célula extraída e depois isolada por lavagem sobre uma rede de nylon. Depois disso, as proteínas de parede celular foram extraídas utilizando dois sais, 0,2 M de CaCl2 e 2 M de LiCl. Para células em suspensão, um protocolo semelhante foi utilizado, contendo, no entanto, um passo anterior de separação da parede celular por meio de maceração e precipitação em glicerol 15%. Usando colmos da mesma idade, dois meses, um protocolo não destrutivo foi testado com base na infiltração a vácuo dos tecidos nos mesmos sais já descritos, 0,2 M de CaCl2 e 2 M de LiCl, e posterior centrifugação. Duas repetições foram usadas nos experimentos com plantas de dois meses de idade, e três, no caso de células em suspensão. As amostras complexas foram digeridas, fracionadas e seqüenciadas por espectrometria de massas, utilizando o equipamento SYNAPT G2HDMS acoplado ao cromatógrafo nanoACQUITY, ambos da Waters. Os peptídeos foram processadas utilizando ProteinLynx 2,5 comparando com a base de dados de ESTs traduzidos da cana. Utilizando programas de bioinformática, como Blast2GO, foi possível encontrar a anotação e classificação de proteínas semelhantes. Apenas proteínas igualmente encontradas em todas as repetições foram consideradas na análise principal. SignalP, WolfPSORT, TargetP, TMHMM e Predotar foram softwares utilizados para prever a localização subcelular, tanto para ESTs como proteínas, e apenas as proteínas preditas para serem secretadas por dois ou mais programas foram consideradas como proteínas de parede celular. Ao todo, 157 SAS diferentes relacionados à parede celular da cana foram encontrados. Dentre eles, 101 diferentes proteínas de parede foram caracterizadas em oito classes funcionais. O método baseado na infiltração a vácuo mostrou-se o mais eficiente, uma vez que apresentou quase metade, 48,84%, das proteínas preditas para serem secretadas, o que é um bom valor quando comparado com outros estudos. A maioria das proteínas secretadas estava relacionada com o metabolismo lipídico, como proteínas de transporte de lípidos, oxido-redutases, tais como peroxidases, enzimas modificadoras da parede, como as glicosil-hidrolases, proteases, proteínas com domínios de interação, proteínas sinalizadoras, entre outras. Os resultados estão de acordo com o papel que se espera da matriz extracelular no metabolismo de polissacarídeos e fenômenos de sinalização. Portanto, este trabalho forneceu informações valiosas sobre a parede celular da cana, tornando possível a utilização desses dados em futuros estudos para otimizar a produção de etanol celulósico.

Orientador: Carlos Alexandre Costa Crusciol
Coorientador: James Mabry McCray
Banca: Rafael Otto
Banca: Raffaella Rossetto
Banca: Ciro Antonio Rosolem
Banca: Henrique Coutinho Junqueira Franco
Resumo: Objetivou-se avaliar o efeito do fornecimento de concentrações de Mg2+e K+, e da aplicação foliar de Mg2+ no desenvolvimento da raiz e parte aérea, bem como possíveis alterações no estado nutricional e na partição de carboidratos em plantas de cana-de-açúcar. Para tanto, três estudos foram conduzidos: i) avaliação do efeito de concentrações de Mg2+ (controle e deficiente) no desenvolvimento de plantas de cana-de-açúcar; ii) alterações metabólicas e nutricionais na cana-de-açúcar decorrentes do desequilíbrio de Mg2+ causado pelo alto nível de K+; iii) eficiência da aplicação foliar de Mg2+ em plantas de cana-de-açúcar cultivadas em nutrição variada de K+ e Mg2+. Os experimentos foram conduzidos em casa de vegetação e as plantas cultivadas em solução nutritiva. Foram avaliados: o teor de clorofila nas folhas, parâmetros morfológicos das raízes (comprimento e diâmetro radicular), produção de matéria seca das partes da planta, composição nutricional e partição de amido, sacarose e açúcares redutores nas diferentes partes da planta. No geral, o adequado fornecimento de Mg2+ levou a maior produção de matéria seca, concentração de sacarose nos colmos e relação raiz/parte aérea. Clorofila a, b e carotenoides foram menores em plantas deficientes em Mg2+. Ademais, foi observado maior concentração de amido e açúcares solúveis nas folhas e menor concentração de sacarose nos colmos destas plantas. Além disso, plantas deficientes em Mg2+ tiveram menor comprimento radicular e maior diâmetro, do que as quais apresentaram maior concentração de K+ na raiz e maior translocação deste cátion para a parte aérea. O aumento da concentração de K+ na solução nutritiva reduziu a concentração de Mg2+ nas raízes, folhas novas, folhas velhas e colmos da cana-de-açúcar, mesmo nas plantas controle de Mg2+. Independente da nutrição com Mg2+, no maior nível de K+, todos os parâmetros ...
Abstract: The aim of this study was to evaluate the effect of Mg2+ and K+ concentrations, and Mg2+ foliar application on the root and shoot growth, as well as to check the alterations on the nutritional status and carbohydrates partitioning in sugarcane plants. For this purpose, three studies were conducted: i) evaluation of the effect of Mg2+ concentrations (adequate and deficient) on the sugarcane plants development; ii) metabolic and nutritional alterations in sugarcane due to Mg2+ imbalance caused by K+ high level; iii) efficiency of the Mg2+ foliar application in sugarcane plants grown under varied levels of K+ and Mg2+. The experiments were estabilished in greenhouse and the plants grown in nutrition solution. The evalutions were: leaf chlorophyll content, root morphological parameters (length and root diameter), dry matter production of plant parts, nutritional composition and starch, sucrose and reducing sugars partitioning in the different plant parts. In general, the adequate supply of Mg2+ resulted in higher dry matter production, sucrose concentration in the stalks and root/shoot ratio. Chlorophyll a, b and carotenoids were lower in Mg2+ deficient plants. Moreover, higher concentration of starch and soluble sugars were observed in the leaves and lower starch concentration in the stalks of these plants. Besides, Mg-deficient plants had shorter root length and larger diameter, which presented higher K+ concentrations in the root and higher translocation of this cation to the ... (Resumo completo, clicar acesso eletrônico abaixo)
Doutor

Various methods for the production of bioethanol using different feedstocks have been researched on. In most work on bioethanol synthesis from sugar cane, tops and leaves have been regarded as waste and generally removed and thrown away. In this work, lignocellulosic sugarcane leaves and tops were not discarded but instead used as biomass to evaluate their hydrolyzate content. The leaves and tops were hydrolysed using different methods, namely concentrated acid, dilute acid pre-treatment with subsequent enzyme hydrolysis and compared with a combination of oxidative alkali pretreatment and enzyme hydrolysis. Subsequent fermentation of the hydrolyzates into bioethanol was done using the yeast saccharomyces cerevisae. Acid hydrolysis has the problem of producing inhibitors, which have to be removed and this was done using overliming with calcium hydroxide and compared to sodium hydroxide neutralization. Oxidative alkali pre-treatment with enzyme hydrolysis gave the highest yields of fermentable sugars of 38% (g/g) using 7% (v/v) peroxide pre-treated biomass than 36% (g/g) for 5% (v/v) with the least inhibitors. Concentrated and dilute acid hydrolysis each gave yields of25% (g/g) and 22% (g/g) yields respectively although for acid a neutralization step was necessary and resulted in dilution. Alkaline neutralization of acid hydrolyzates using sodium hydroxide resulted in less dilution and loss of fermentable sugars as compared to overliming. Higher yields of bioethanol, 13.7 (g/l) were obtained from enzyme hydrolyzates than 6.9 (g/l) bioethanol from dilute acid hydrolyzates. There was more bioethanol yield 13.7 (g/l) after 72h of fermentation with the yeast than 7.0 (g/l) bioethanol after 24h. However, the longer fermentation period diminishes the value of the increase in yield by lowering the efficiency of the process.

Thesis (MSc)--University of Stellenbosch, 2004.
ENGLISH ABSTRACT: The process of sugar accumulation and transport in sugarcane is still poorly understood. Understanding the processes involved in sucrose transport are important, since membrane transport might be important control points in this pathway. The goals of this project were to unravel the mechanisms of sugar transport in sugarcane culm tissue by using 14C-sugar analysis as well as molecular techniques to identify possible sucrose transporters. Developing (internode 2 and 4) and maturing (internode 8 and 15) culm tissue of sugarcane (Saccharum hybrid) commercial variety N19 was used for all tissue disc experiments. Tissue discs from internodes of different developmental stages were cut from field grown sugarcane plants (cv. N19) and the uptake of 14C-labelled glucose, fructose and sucrose measured. The uptake rates were measured at varying pH, temperature and concentrations of sugars. Hexoses were found to be the major sugar taken up and sucrose was only important when little hexose was available, as was found in the mature ripe internodes. Sucrose uptake differs between tissues and our study showed that sucrose was taken up rapidly at pH 5, similar to the pH optimum of most sucrose transporters Inhibition studies with TRIS (2-amino-2- (hydroxymethyl)-1,3-propanediol) and PCMBS (p-chloromercuribenzenesulphonic acid) indicated that more than one sucrose transporter activity may be present in the sugarcane system at different sucrose concentrations. To date work on sugarcane sucrose transporter expression on DNA and RNA level has been limited. Only recently a sucrose transporter from Saccharum hybrid sugarcane stem cDNA libray, ShSUT1 (Saccharum hybrid Sucrose Transporter ) was isolated and functionally characterized in the yeast strain SEY 6210 (Rae et al., 2004). In an effort to understand sucrose transport in sugarcane culm tissue, a partial sucrose transporter cDNA, ScSUT1(p) from Saccharum hybrid sugarcane a bud cDNA library was isolated, and cloned from a bud cDNA library. The clone was designated ScSUT(p) as a partial Sugarcane Sucrose Transporter. The ScSUT1(p) sequence showed 94% identity to ShSUT1 on nucleotide level over 1258 nucleotides and had an estimated open reading frame of 419 amino acids. Southern blot analysis indicated that the transporter had a low copy number and the ScSUT1(p) transcript expression was constitutive in sucrose accumulating and sucrose storing stem tissue, but was less abundant in immature tissue such as internodes 2 and 3 and in lateral buds. It was concluded that the primary function of ScSUT1(p), was not phloem unloading but that the transporter may be involved in phloem loading, as it is abundant in mature source leaves. ShSUT1 cDNA was obtained from Dr C Grof and the functionality of ShSUT1 as a sucrose transporter in Xenopus leavis oocytes was confirmed. However, electrophysiological measurements on the oocytes demonstrated no measurable current associated with sucrose challenge to the oocytes indicating that the transporter activity was either very low or possibly non-electrogenic. Further investigation is required to characterise the specific mechanism and kinetic properties of this transporter.
AFRIKAANSE OPSOMMING: Die proses van suikerakkumulering en -vervoer in suikerriet word steeds baie vaag verstaan. ‘n Deeglike begrip van die prosessewat betrokke is in die vervoer van sukrose is baie belangrik omdat transmembraan vervoer moontlik een van die belangrike beheerpunte in metabolisme mag wees. Die doelwitte van die studie was om ‘n beter begrip te bekom van die meganisme wat betrokke is by die vervoer en berging van sukrose in suikerriet. Die projek is in ‘n fisiologiese en ‘n molekulêre afdeling verdeel. In die fisiologiese afdeling is stingelweefsel van ‘n Saccharum hybried (variëteit N19) van verskillende stadiums van ontwikkeling (internodes 2-4, internode 8 en internode 15) gebruik. Opname van radioaktiewe (14C) sukrose, glukose en fruktose is as analise metode gebruik vir die suikeropname eksperimente. Die invloed van pH, suiker konsentrasie en inhibitore soos PCMBS (pchloromercuriphenylsulfonic acid) en TRIS (2-amino-2-(hydroxymethyl)-1,3-propanediol) op die tempo van suikeropname is ondersoek. Die molekulêre deel fokus hoofsaaklik op die identifisering, isolering en karakterisering van nuwe sukrose vervoerproteine in suikerriet, met behulp van PCR en heteroloë uitdrukking in Xenopus laevis oösiete. Die 14C - opname eksperimente het tot die volgende gevolgtrekkings gelei: Heksoses speel die belangrikste rol in die vervoer van suiker in die riet as daar min of geen sukrose teenwoordig is nie. Sodra daar sukrose in groot mate teenwoordig is soos in die geval van ontwikkelde, ryp internodes, is die rol van sukrose egter belangriker. Sukrose is die maklikste opgeneem by pH 5, wat naby die pH optimum van die meeste sukrose vervoerproteïene is. TRIS en PCMBS het beide ‘n inhiberende effek op sukrose opname gehad, maar die invloed was groter by die laer sukrose konsentrasies. Tot onlangs was daar baie min inligting oor sukrose vervoer in suikerriet op DNA en RNA vlak. Die eerste sukrose vervoerprotein uit suikerriet, ShSUT1 (Saccharum Hibried Sukrose Transporter) is eers onlangs uit ‘n stingel - cDNA biblioteek geïsoleer (Rae et al., 2004) en die funksionering daarvan is in ‘n gisras (SEY6210) getoets. In my pogings om sukrose vervoer te verstaan is ‘n gedeeltelike cDNA, naamlik ScSUT(p) (partial Sugarcane Sucrose Transporter) van 1258 nukleotiede, uit cDNA afkomstig van suikerrietbotsel geïsoleer. Die nukleotiedvolgorde stem 94% ooreen met ShSUT1 en kodeer vir ‘n moontlike oopleesraam van 419 aminosure. Southern analises het aangedui dat ScSUT(p) ‘n lae kopie getal het, in ooreenstemming met wat vir ander sukrose vervoerproteïene gevind is. Northern analises het getoon dat die uitdrukking van ScSUT(p) konstitutatief is in sukrose akkumulerende sowel as sukrose bergingsweefsel. Jong weefsel (internode 2 en 3) het baie lae uitdrukking getoon, met die hoogste uitdrukking in blaarweefsel. Uit die resultate is afgelei dat ScSUT(p) ‘n rol in floeëmlading en -ontlading mag speel. Xenopus laevis oösiete, is as ‘n heteroloë uitdrukking sisteem gebruik om te bevestig dat ShSUT1 as ‘n sukrose vervoerproteïen funksioneer. Elektrofisiologie het nie daarin geslaag om ShSUT1 se spesifieke werkingsmeganisme te identifiseer nie. Aanduidings is egter gevind dat ShSUT1 moontlik nie as ‘n H+/sukrose simportsisteem werk nie, maar by gefasilliteerde vervoer van sukrose betrokke mag wees. Verdere navorsing is noodsaaklik om die meganisme van ShSUT1 se werking te verstaan.

Thiazole biosynthetic protein (THI1) is involved in the synthesis of the thiazole ring, a thiamine (vitamin B1) component. Thiamine is an essential co-factor in several carbohydrate and amino acid metabolic pathways. Prokaryotes and a few eukaryotes, such as fungi and plants, are able to synthesize thiamine de novo. These organisms contain the genes that encode the corresponding enzymes (such as THI1) that perform this metabolic function. THI1 actually functions as a reagent rather than as a conventional catalytic enzyme, as the THI1 polypeptide itself serves as the sulfide donor for thiazole formation. This gene also plays a role in organelle DNA damage tolerance. Arabidopsis thaliana has only one copy of the thi1 gene (At-thi1). Transcripts derived from At-thi1 are targeted simultaneously to chloroplasts and mitochondria by differential usage of two in-frame initiation codons. The tz-201 A. thaliana thi1 mutant has been shown to accumulate more sucrose in its tissues than wild-type plants. This suggests that a better understanding of thi1 genes and the role they play in cellular sucrose accumulation may be relevant for improving commercially important crops such as sugarcane. Sugarcane (Saccharum spp.) is a C4 photosynthesis monocot. Unlike A. thaliana, sugarcane has at least two thi1 copies (sc-thi1.1 and sc-thi1.2), as do the other C4 grasses. This thesis concerns the molecular and functional analyses of sugarcane thi1 (sc-thi1) gene homologues. The identified alleles related to sc-thi1.2 have some differences in sequence and seems to be diverging into two subgroups (sc-thi1.2a and sc-thi1.2b), based on phylogenetic analyses. Expression analysis showed that each sc-thi1 copy is expressed differentially in individual tissues and in developing stages levels. Subcellular analysis showed that sc-thi1.1 and sc-thi1.2b have the same cellular distribution pattern, distinct from the observed for sc-thi1.2a. Sc-thi1.1 and sc-thi1.2b were also able to partially complement thiamine auxotrophy in a yeast mutant deficient in thiamine biosynthesis. A similar complementation assay is not possible in the A. thaliana tz-201 mutant owing to low transformation efficiencies. Thus, Physcomitrella patens was chosen to generate thi1 mutant lines for future functional complementation studies. P. patens is a moss used as a plant model, with a small size, short life cycle and a haploid dominant phase. Despite its simplicity, it has six thi1 homologues copies. Homologous Recombination was used to generate P. patens thi1 mutants. In each case, a target thi1 gene was disrupted by replacing its coding region with an antibiotic resistance gene cassette. Single mutants were obtained for all six thi1 gene copies. All the knockout lines were able to survive and grow with only minor effects on morphology and physiology. Deletion of one of the thi1 gene copies (PpThi1.20F) drastically affected protoplast survival and regeneration, suggesting a role for this gene in early (polar) cell division and differentiation. The experimental design, which permits recycling of the selectable marker cassettes, provides a research platform for the construction of double, triple, quadruple or quintuple mutants in the future. The individual mutants line generated in this work, as well as the possible multiple mutants, will be useful for thi1 functional complementation experiments and for discerning the specific functions of individual thi1 gene family members.
THI1 (proteína da biossíntese de tiazol) está envolvida na síntese do anel de tiazol, um componente de tiamina (vitamina B1). A tiamina é um cofator essencial em várias vias metabólicas de carboidratos e aminoácidos. Somente procariontes e alguns eucariontes, como fungos e plantas, são capazes de sintetizar a tiamina de novo. A proteína THI1 atua mais como um reagente do que como uma enzima catalítica convencional, pois usa a si mesmo como doador de sulfeto para a formação do anel de tiazol. Este gene também está envolvido na tolerância ao dano no DNA das organelas. A. thaliana apresenta apenas uma cópia do gene thi1. Seu transcrito primário é direcionado simultaneamente aos cloroplastos e mitocôndrias através do uso diferencial de dois códons de iniciação, presentes no mesmo quadro aberto de leitura. Além disso, o mutante tz-201 de A. thaliana acumula mais sacarose em seus tecidos do que a planta selvagem. Isso sugere que um melhor entendimento do gene thi1 e seu papel no acúmulo de sacarose podem ser importantes para o melhoramento comercial de cultivares, como cana-de-açúcar. Cana-de-açúcar (Saccharum spp.) é uma monocotiledônea de metabolismo fotossintético C4. Diferentemente do observado em A. thaliana, a cana-de-açúcar possui pelo menos duas cópias (sc-thi1.1 e sc-thi1.2) homólogas a thi1, como observado também para outras gramíneas C4. Nesta tese são discutidas análises moleculares e funcionais dos homólogos do gene thi1 (sc-thi1) de cana-de-açúcar. Os alelos identificados como relativos a sc-thi1.2 apresentam algumas diferenças em suas sequências e, baseado em análises filogenéticas, parecem estar divergindo em dois subgrupos (sc-thi1.2a e sc-thi1.2b). As análises de expressão mostraram que cada cópia de sc-thi1 é diferencialmente expressa em diferentes tecidos e estágios de desenvolvimento. A análise de localização subcelular mostrou sc-thi1.1 e sc-thi1.2b apresentam o mesmo padrão de distribuição, distinto do observado para sc-thi1.2a. Sc-thi1.1 e sc-thi1.2b também foram capazes de complementar parcialmente a auxotrofia para tiamina em leveduras mutantes, deficientes na via de biossíntese de tiamina. Um teste similar de complementação funcional mutante tz-201 de A. thaliana não é possível no devido à baixa eficiência de transformação. Assim, Physcomitrella patens foi escolhida para gerar linhagens mutantes de thi1 para futuros estudos de complementação funcional. P. patens é um musgo usado como planta modelo, apresenta tamanho pequeno, um ciclo de vida curto e uma fase dominante haploide. Apesar de sua simplicidade, possui seis cópias homólogas a thi1. A técnica de Recombinação Homóloga foi escolhida para gerar os mutantes thi1 de P. patens. Em cada mutante, uma das cópias de thi1 foi interrompida, substituindo sua região codificante por um cassete de gene de resistência. Mutantes individuais foram obtidos para as seis cópias do gene thi1. As linhagens knockouts foram capazes de sobreviver e crescer apenas com alguns pequenos efeitos em sua morfologia e fisiologia. A deleção de uma das cópias de thi1 (PpThi1.20F) afetou drasticamente a sobrevivência e regeneração dos protoplastos, sugerindo um papel deste cópia gênica no inicio da divisão e diferenciação celular. O desenho experimento utilizado para a geração destes mutantes permite a reciclagem dos cassetes de seleção, fornecendo uma plataforma para a construção de duplos, triplos, quádruplos, quíntuplos e sêxtuplos mutantes no futuro. Os mutantes individuais para cada cópia de thi1 gerados nesse trabalho, bem como os possíveis mutantes múltiplos, serão úteis para experimentos de complementação funcional e o discernimento de funções específicas de diferentes membros da família gênica thi1.

Sugarcane is considered as the most abundant plant based crop grown in the tropics and part of the temperate climates. Its by-product, sugarcane bagasse, constitutes 30% of the total production. In the past, it was considered as waste material but contemporaries through innovative research projects over the years have found uses for it. Among these projects is soil reinforcement, which provides an alternative application to industrial by-products and natural fibres as a way of reducing their environmental footprints and contributing to sustainable geotechnics. Although bagasse morphological composition contains structural elements ideal for reinforcement and composite materials, it has received little research as a standalone reinforcement material. Because of this, a direct shear test was therefore initiated to establish the usefulness of using sugarcane bagasse as a soil reinforcement material by comparing the extent of shear strength and stiffness response due to its inclusion to unreinforced soil. Three different types of bagasse, fibre, millrun and pith, were added to unreinforced soil in percentage by weight content of 0.3 - 1.7. The bagasse was added to Klipheuwel sand, Cape Flats sand and Kaolin Clay at both dry and moist conditions. In addition, durability studies involving 12 cycles of wetting and drying, and soaking for a period of 14 days were constituted.

Bibliography: leaves 68-71.
The Kenyan sugar industry continues to face the task of being competitive in a liberalized global economy that has witnessed a trend in declining sugar prices and increasing local production costs. This dissertation attempts to investigate possible options that could assist Kenyan sugar industry to cope with the crisis. One such option is the diversification of the sugar industry's product base. Expanding their business to energy as a co-product to sugar processing, sugar companies could generate additional revenue from surplus electricity sales to the national utility. In Mauritius, gross revenue of USD 50 million, equivalent to 90% of that accruing to the miller for cane processing is generated from bagasse-based energy sales. On the basis of the Mauritian and other experiences the research concludes that Kenya sugar industries have the potential to export 43, 258, and 306 GWh of electricity to the national grid, depending on the mode of operation of the power plant. Thus the potential for revenue expansion through power sales for the Kenyan sugar industry is substantial. Power sector reforms have seen the entry into the electricity market of independent power producers (IPPs), and so this presents a good opportunity for sugar companies to enter into power purchase agreements with the national utility for the supply of power. Anaerobic digestion systems, used in the treatment and management of industrial effluent provide an additional benefit of generating boiler fuel in the form of biogas in sugar industries of Kenya. This technology and its application to the sugarcane industry are reviewed as part of this thesis.

This work was stimulated by the fact that supplies of fossil fuels are finite, while there are abundant renewable forms of energy waiting to be tapped. The current fossil fuels store is reviewed before identifying usable forms of renewable energy which could replace or supplement fossil fuels. Bagasse - a solid byproduct in sugarcane milling - is then described in detail as a typical lignocellulosic waste which forms part of a larger class of renewable energy sources called biomass. The chemical and physical characteristics, as well as world-wide regions of production of bagasse are described. The research work therefore concerned itself with investigating various physical methods of conserving renewable energy by improving on the extraction efficiency of such energy from bagasse. The equipment used for carrying out the research work is described in detail in chapter two. The methods employed in carrying out the investigations are similarly described in the same chapter, detailing every step in the investigations, including any precautions which had to be taken. The crude results from the investigations are analysed in detail in chapter three so that fuel combustion, combustion oxygen demand, heat and mass balances for the process are considered. An analysis of the boiler system - the main equipment in the investigations - is also carried out in chapter three so that temperatures, gas flow patterns, particle elutriations and size distributions of the fuel in the system are established. Conclusions of the investigations are then drawn from the analyses of chapter three. As a prelude to the conclusion of the work, an industrial biomass survey carried out in Tanzania is analysed to show that bagasse is not the only lignocellulosic which is produced industrially, and that reasonable financial savings can be obtained from these other lignocellulosics. The work concludes by describing a few areas of related research interest for further investigation.

History
Ph.D.
Over the course of the nineteenth century, the Hawaiian sugar industry rose from economic insignificance to become one of the world’s most efficient and productive sugarcane plantation systems. "Planter's Paradise" traces the transnational environmental history of cane planting in Hawaiʻi, from Polynesian settlement to the early twentieth century, to explore how an export-based mono-culture plantation system eclipsed diversified farming, how cultural encounters between indigenous and Euro-American groups influenced agriculture and natural resource use, and how the politics of planting contributed to the rise of American hegemony over the islands. With research grounded in plantation records, agricultural association publications, popular media, and personal correspondence, I address sugarcane planting as a point where ideas about nature, methods of converting nature into commodities for consumption in distant markets, and nature itself influenced each other within the context of U.S. imperial expansion. I argue that the ascendance of Hawaiʻi’s sugar industry was the result of cultural encounters, economic relations, and environmental conditions at the local level, but cane planting also connected the archipelago to particular transnational networks of economic, ecological, and cultural exchange. Sugarcane planting introduced to Hawaiʻi foreign ways of relating to the natural world, a host of alien organisms, and advances in agricultural science and technology that impacted all of Hawaiian society. These introductions contributed to planters' power. By the early twentieth century, Hawaiʻi had become a planter's paradise: a society and environment transformed for the industrial cultivation of sugarcane.
Temple University--Theses

PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
O crescimento da demanda por energia elétrica e investimentos governamentais em fontes renováveis incentivam produtores do setor sucro-energético no país a buscar melhorias nos processos de suas usinas. Através do aumento da produção de vapor nas caldeiras de biomassa, que operam com ciclos Rankine, é possível gerar energia elétrica excedente para comercialização. O Brasil, um dos maiores produtores de cana-de-açúcar do mundo, gera resíduos derivados da cana com alto potencial energético. Os ciclos termodinâmicos híbridos têm sido utilizados em várias usinas de biomassa no exterior utilizando como combustíveis o gás natural e resíduos sólidos urbano (waste-to-energy). Como mostrado por diferentes autores, é possível, com estes ciclos, melhorar a eficiência térmica das usinas utilizando gases quentes da exaustão de uma turbina a gás operando com gás natural. A desvantagem é que o percentual de participação do gás natural de alguns ciclos híbridos pode ser alto, tornando estes projetos economicamente inviáveis. Neste trabalho será aplicado um ciclo híbrido adaptado para usinas de cana-de-açúcar brasileiras que queimam o bagaço em caldeiras de biomassa com reaquecimento externo. Os benefícios destes ciclos termodinâmicos incluem a melhoria de eficiência da planta, acarretando a maior geração de energia elétrica e aumento da quantidade de vapor de processo produzido para a mesma quantidade de bagaço queimado originalmente. Além da melhoria da eficiência térmica, o ciclo tem como uma de suas principais vantagens o fato de não depender de grandes quantidades de gás natural, reduzindo a possibilidade de prejuízos caso haja aumento do seu preço. Por último será mostrado que, embora haja a queima deste combustível fóssil, é possível reduzir as emissões específicas de CO2/kWh devido ao seu baixo consumo na usina aliado a elevada geração de energia elétrica.
The growing electric energy demand and government investments in renewable sources motivated sugar producers in Brazil to improve the thermal efficiencies of their sugarcane plants. For this reason, to generate excess electric energy and to sell it, has become an important and extra source of revenue. This country, one of the biggest sugarcane producers in the world, employs sugar waste, with high energetic potential, in boilers operated with Rankine cycles. Thermodynamic hybrid cycles have been in use in several biomass plants abroad, using natural gas and municipal solids waste as fuels. As shown by different authors, it is possible to increase the thermal efficiency of these plants by means of the heat recovery from hot exhaust gases of a gas turbine operating with natural gas. The main disadvantage of hybrid cycles, for some cases, is the high fraction of natural gas as fuel, making these specific plants economically unfeasible. In this work, a hybrid cycle concept is presented and studied, adapted for Brazilian sugar cane plants which burn bagasse in biomass boilers with reheating systems. The benefits of these thermodynamics cycles include a thermal efficiency improvement thus allowing more power generation and higher production of process steam, for the same amount of bagasse originally burned. Besides the higher thermal efficiency, the hybrid cycle presents the advantage of not depending on large natural gas consumption. This makes the plant s economic feasibility less dependent on fluctuations on natural gas prices. Furthermore, this study shows that, although a fossil fuel is burned, it is possible to reduce CO2/kWh specific emissions due to lower consumption of fossil fuels and to higher power generation.

Laboratory experiments were conducted to characterise the germination of some tropical weed seeds. Field experiments in Sri Lanka characterised the seed bank and monitored seedling emergence after sugarcane planting. In laboratory experiments, final germination, median germination time and rate of germination were determined on a Temperature Gradient Plate and used to define values for optimum temperature (T_o), base temperature (T_b), and upper temperature limit for germination (T_m). Final germination, median germination time and rate of germination were also evaluated to study germination response to water availability. Field studies were conducted in Sri Lanka to estimate the seed rain and the bank and also to monitor seedling emergence after sugarcane planting. Taylor's Power Law (TPL) parameters were used to describe the spatial distribution of seeds in the seed bank. The Principal Components Analyses (PCA) was used to summarise the variation between samples and species. The Shannon-Weaver diversity index was used to estimate species diversity in the seed bank. Chi-square analyses (x²) were performed to assess the species similarity of the seed bank and the emerged vegetation. Seedling emergence in the field was examined for relationships with rainfall, soil moisture and soil temperatures. The seed rain fluctuated with time. The higher seed rain in fallow land increased the density of the seed bank particularly near the surface. Ploughing substantially reduced the seed bank (by about 80%) and mixed seeds more evenly through the ploughed layer. The majority of seedlings (98%) emerged from the top 4.0cm of soil. Hot and humid conditions favoured the germination and emergence of weed seedlings. This was seen not just in comparison of plantings in October 1995, January 1996 and April 1996 but also more seedlings emerged in the furrows than on ridges. There was no similarity of the species composition of the seed bank and the seedling population arising. Also, the abundance of common species in the seed bank and emerged vegetation was poorly correlated. There was a little relationship between seedling emergence and soil temperature in this investigation.

PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO
O bagaço da cana-de-açúcar é uma biomassa vegetal que possui muito potencial de uso devido aos seus três elementos estruturais: celulose, hemicelulose e lignina. Para servir como matéria prima na produção de insumos, o bagaço da cana-de-açúcar precisa passar por um processo de pré-tratamento. Nesse estudo, duas metodologias para o processo de pré-tratamento do bagaço da cana-de-açúcar foram utilizadas: a deslignização via peróxido de hidrogênio (H2O2) e via dióxido de carbono supercrítico (ScCO2). Para o estudo utilizando H2O2, foram desenvolvidos modelos a partir de planejamento experimental, Algoritmos Genéticos (GA, do inglês Genetic Algorithms), Redes Neurais Artificiais (RNA) e Neuro-Fuzzy (ANFIS). As variáveis independentes foram temperatura (25 – 60 graus Celsius), concentração de H2O2 (2 – 15 por cento m/v) e pH (10 – 13), tendo como resposta os teores de lignina residual e oxidada no processo, através de análises de FT-IR e análise pelo método de Klason. Para o estudo utilizando ScCO2 foram construídos modelos a partir de RNA e ANFIS. As variáveis estudadas no processo foram: temperatura (35 – 100 graus Celsius), pressão (75- 300 bar) e teor de etanol na solução de co-solvente (0 – 100 graus Celsius). De modo geral, para os dois processos, os modelos desenvolvidos consideram as variáveis independentes como sendo neurônios na camada de entrada e as variáveis dependentes como sendo neurônios na camada de saída. Todos os modelos neurais e ANFIS desenvolvidos neste trabalho foram avaliados pelo coeficiente de correlação e índices de erro (SSE, MSE e RMSE), além do número de parâmetros. Os resultados mostraram que, dentre estas estratégias estudadas, os modelos neurais se mostraram mais satisfatórios para predição das respostas do pré-tratamento com H2O2, já que se encaixa nos índices de performance estipulados. O mesmo ocorreu no modelo neural para predição do teor de lignina residual no pré-tratamento com ScCO2. Para cada modelo polinomial e neural desenvolvido, foi realizada a investigação das superfícies de respostas e das curvas de contorno. Com esse recurso, foi possível a identificação dos melhores pontos operacionais para os processos, visando a minimização dos teores de lignina residual e oxidada na biomassa.
Sugarcane bagasse is a plant biomass that has a great potential for use due to its three structural elements: cellulose, hemicellulose and lignin. To serve as raw material in the production of other products, sugarcane bagasse needs to undergo a pre-treatment process. In this study, two methodologies for the sugarcane bagasse pretreatment process were used: delignification via hydrogen peroxide (H2O2) and via supercritical carbon dioxide (ScCO2). The models for study the process with H2O2 were developed from experimental planning, Genetic Algorithms (GA), Artificial Neural Networks (ANN) and Neuro-Fuzzy (ANFIS). The independent variables were: temperature (25- 60 degrees Celsius), H2O2 concentration (2 - 15 percent m/v) and pH (10-13). The residual and oxidized lignin contents in the process were evaluated from FT-IR and Klason method analysis. The models for study the process with ScCO2 were developed from RNA and ANFIS. The variables studied in the process were: temperature (35-100 degrees Celsius), pressure (75-300 bar) and ethanol content in the aqueous solution of co-solvent (0-100 percent). In general, for the two processes, the developed models consider the independent variables to be neurons in the input layer and the dependent variables to be neurons in the output layer. All the neural and ANFIS models developed in this study were evaluated by the correlation coefficient and error indexes (SSE, MSE and RMSE), as well as the number of parameters. From the stipulated indices of performance, among the results obtained by the different strategies, the neural models were the most satisfactory for the prediction of pretreatment responses with H2O2. The same occurred in the neural model for prediction of the residual lignin content in the pre-treatment with ScCO2. Response surfaces and the contour curves were investigated for each polynomial and neural model developed. With this resource, it was possible to identify the best operational points for the processes, pointing at minimizing the residual and oxidized lignin contents in the biomass.

Dissertation (PhD)--University of Stellenbosch, 2004.
ENGLISH ABSTRACT: This study had three main goals: 1. to investigate the occurrence on the protein level of sucrose synthase (SuSy) isoforms in sugarcane sink tissue, 2. to determine the kinetic properties of these isoforms, 3. to establish the tissue localisation of SuSy in the sugarcane culm The results are summarised below: Three SuSy isoforms were obtained from leaf roll tissue. The SuSyA and SuSyB isoforms differed in terms of charge characteristics, with SuSyA not binding to an anion exchange column that bound SuSyB and SuSyC under the same conditions. Both SuSyB and SuSyC isoforms were eluted at 180 mM KCl. The SuSyA and SuSyB isoforms were present during autumn, but during winter only the SuSyC isoform could be isolated. Even though they eluted at the same salt concentration, SuSyB and SuSyC were different isoforms, because they had different kinetic parameters, as well as different immunological properties. SuSyB and SuSyC could not have been mixtures of the same isoforms, since a polyclonal antiserum against SuSyB, which inactivates native SuSyB, did not inactivate SuSyC. All three isoforms had significantly different kinetic parameters, with the SuSyA isoform also having a much lower sucrose breakdown/synthesis ratio than the other two isoforms. Therefore, at least three SuSy isoforms occur in sugarcane leaf roll tissue on the protein level. The SuSyC isoform was subsequently kinetically characterised in detail. Data showed that the enzyme employs an ordered ternary complex mechanism, with UDP binding first and UDP-glucose dissociating last. These experimentally obtained kinetic parameters were then used to extend a kinetic model of sucrose accumulation. Data show that when the experimentally determined SuSy kineticparameters were entered into the model, a 40 % increase in sucrose concentration and 7 times reduction in fructose concentration resulted. These data illustrate the pronounced physiological effects that may result from the presence of different SuSy isoforms. SuSy protein localisation data, obtained by an immunohistochemical approach, indicated that SuSy protein was present in both storage parenchyma and vascular tissue of young, intermediate, and mature internodes. SuSy enzyme activity in different parts of the internodes was similar, except for internode 3, which had much higher activity in the bottom part of the internode, possibly because growth is faster here, hence a higher demand for sucrose cleavage exists here.
AFRIKAANSE OPSOMMING: Hierdie studie het ten doel gehad: 1. om die teenwoordigheid van sukrose sintase (SuSy) isovorme in suikkerriet swelgweefsel te ondersoek 2. om die kinetiese eienskappe van hierdie isovorme te ondersoek 3. om die weefsellokalisering van SuSy in die suikerrietstingel te bepaal Die resultate word hieronder opgesom: Drie SuSy isovorme is gevind in blaarrol weefsel. Die SuSyA en SuSyB isovorme het verskil in terme van ladingseienskappe, met SuSyA wat nie aan ‘n anioonuitruilkolom gebind het nie waaraan SuSyB en SuSyC wel onder dieselfde kondisies gebind het. Beide SuSyB en SuSyC isovorme is geëlueer van die kolom teen 180 mM KCl. Die SuSyA en SuSyB isovorme was teenwoordig gedurende herfs, maar in die winter was slegs SuSyC teenwoordig. Ten spyte van die feit dat SuSyB en SuSyC teen dieselfde soutkonsentrasie geëlueer is, het hulle verskillende isovorme verteenwoordig, aangesien hulle kinetiese en immunologiese eienskappe verskil het. SuSyB en SuSyC kon nie mengsels van dieselfde isovorme gewees het nie, want ‘n poliklonale antiserum teen SuSyB, wat SuSyB geïnaktiveer het, het nie SuSyC geïnaktiveer nie. Al drie isovorme het betekenisvol verskil wat kinetiese eienskappe betref, met die SuSyA isovorm wat ook ‘n baie laer sukrose afbraak/sintese verhouding gehad het as die ander twee isovorme. Daar is dus ten minste drie SuSy isovorme teenwoordig op die proteïen vlak in suikerriet blaarrol weefsel. Die in-detail kinetiese analise van die SuSyC isovorm het getoon dat die ensiem ‘n geordende drietallige kompleks meganisme het, met UDP wat eerste bind en UDP-glukose wat laaste dissosieer. Die eksperimenteel bepaalde kinetiese parameters is toe gebruik om ‘n kinetiese model van sukrose akkumulering uit tebrei. Data het getoon dat wanneer die generiese SuSy kinetiese parameters in die oorspronklike model vervang word met die eksperimenteel bepaalde waardes, die berekende sukrose konsentrasie met ongeveer 40 % toeneem, terwyl die fruktose konsentrasie ongeveer 7 keer afneem. Hierdie resultaat toon die groot fisiologiese effek wat die uitdrukking van verskillende SuSy isovorme op suikermetabolisme kan hê. Die SuSy proteïen lokaliseringsdata, wat met ‘n immunohistochemiese benadering verkry is, het aangedui dat SuSy in beide bergingsparenchiemselle sowel as vaatweefsel teenwoordig is in jong, intermediêre en volwasse internodes. SuSy ensiemaktiwiteit in verskillende dele van die internodes was soortgelyk, behalwe in internode 3, wat baie hoër aktiwiteit gehad het in die onderste deel van die internode as bo, moontlik weens vinniger groei in hierdie deel van die internode, wat afhanklik is van afbraakprodukte van sukrose.

Thesis (MSc (Plant Biotechnology))--University of Stellenbosch, 2006.
Fructose 2,6-bisphosphate (Fru 2,6-P2) is an important regulatory molecule in plant carbohydrate metabolism. There were three main objectives in this study. Firstly, to determine whether the recombinant rat 6-phosphofructo 2-kinase (6PF2K, EC 2.7.1.105) and fructose 2,6-bisphosphatase (FBPase2, EC 3.1.3.11) enzymes, which catalyse the synthesis and degradation of Fru 2,6-P2 respectively, showed any catalytic activity as fusion proteins. Secondly, to alter the levels of Fru 2,6-P2 in sugarcane, an important agricultural crop due to its ability to store large quantities of sucrose, by expressing the recombinant genes. Thirdly, to investigate whether sugar metabolism in photosynthetic- (leaves) and non-photosynthetic tissue (internodes) were subsequently influenced. Activity tests performed on the bacterially expressed glutathione-S-transferase (GST) fusion 6PF2K and FBPase2 enzymes showed that they were catalytically active. In addition antibodies were raised against the bacterially expressed proteins. Methods for extracting and measuring Fru 2,6-P2 from sugarcane tissues had to be optimised because it is known that the extraction efficiencies of Fru 2,6-P2 could vary significantly between different plant species and also within tissues from the same species. A chloroform/methanol extraction method was established that provided Fru 2,6-P2 recoveries of 93% and 85% from sugarcane leaves and internodes respectively. Diurnal changes in the levels of Fru 2,6-P2, sucrose and starch were measured and the results suggested a role for Fru 2,6-P2 in photosynthetic sucrose metabolism and in the partitioning of carbon between sucrose and starch in sugarcane leaves. Transgenic sugarcane plants expressing either a recombinant rat FBPase2 (ODe lines) or 6PF2K (OCe lines) were generated. The ODe lines contained decreased leaf Fru 2,6-P2 levels but increased internodal Fru 2,6-P2 levels compared to the control plants. Higher leaf sucrose and reducing sugars (glucose and fructose) were measured in the transgenic plants than the control plants. The transgenic lines contained decreased internodal sucrose and increased reducing sugars compared to the control plants. Opposite trends were observed for Fru 2,6-P2 and sucrose when leaves, internodes 3+4 or internodes 7+8 of the different plant lines were compared. In contrast, no consistent trends between Fru 2,6-P2 and sucrose were evident in the OCe transgenic lines.

Thesis (MSc)--Stellenbosch University, 2013.
ENGLISH ABSTRACT: See item for full abstract
AFRIKAANS OPSOMMING: Sien item vir volteks
IPB, National Research Foundation (NRF) and SASRI for funding

Currently, the cropping area is around 10 million hectares, in which the sugarcane fields are expanding for marginal regions, mainly where grains and pasture were previously cultivated. From that, the objectives of this study were: to calibrate and evaluate a sugarcane yield model using data from 12 fields conducted under high technology field conditions; to evaluate the performance of a gridded system (NASA/POWER) to increase the spatial density of the weather stations in Brazil, to be employed as input data of crop simulation models; to map, in micro-region scale, the potential (Yp), the best farmer\'s (Ybf) and average actual (Yavg) sugarcane yields in Brazil, in order to determine the sugarcane yield gaps by water deficit (YGWD) and by crop management (YGCM), and to define strategies for a most sustainable sugarcane crop production. The yield model showed a good performance in the yield simulation, during the calibration and validation phases. The estimated yield in the calibration phase was 81.9 Mg ha-1 while the observed one was 82.3 Mg ha-1. In the validation phase, the estimated yield was 82.9 Mg ha-1 and the observed was 86.9 Mg ha-1. These results suggested that this kind of model can be used for yield estimation, mainly for agricultural planning purposes, at regional and national scales. The NASA/POWER weather data showed a reasonable performance when compared to observed data that control Yp (solar radiation and air temperature). On the other hand, although the annual average rainfall were very similar in all locations evaluated, this variable presented unsatisfactory statistical coefficients (R2 = 0.60 and MAPE = 233.4%), being suggested, therefore, to replacement of rainfall data from the gridded system by the ones from local rainfall stations (ANA). In the majority of the locations, the percentage errors of Yp were ±15%, while the attainable yield was overestimated by 14% when estimated without replace the rainfall data by the ANA\'s data. Otherwise, when the rainfall data were modified by the ones from ANA, a better adjustment was obtained, revealing an overestimation of only 5%. Finally, 259 virtual weather stations were generated with NASA/POWER data and rainfall from ANA database to estimate yields. The yield types were spatialized through software ArcGis 9.3® at micro-region level. The yield gaps by water deficit and crop management were determined. It was observed that the sugarcane yield losses in Brazil are mainly caused by water deficit (74% of total yield gap), while 26% was due crop management. These results contribute for a better understanding about the factors that control sugarcane production and, therefore, they can be used to define strategies, such use of drought tolerant cultivars, irrigation, and soil decompaction, to make sugarcane production in Brazil more efficient and sustainable.
Atualmente, a cana de açúcar ocupa uma área de aproximadamente 10 milhões de hectares, revelando um pronunciado avanço dos canaviais para regiões marginais, onde anteriormente predominavam os cultivos de grãos e pastagens. Assim, os objetivos deste estudo foram calibrar e avaliar um modelo de estimativa da produtividade de colmos da cana de açúcar em 12 locais, sob elevado padrão tecnológico e operacional de cultivo; avaliar o desempenho de um sistema de dados meteorológicos em grid (NASA/POWER, 1°x1°) para incrementar a densidade espacial de estações meteorológicas no Brasil para serem empregados em modelos de simulação de culturas; e mapear, a produtividade potencial (Yp), a produtividade obtida pelos produtores com elevado nível tecnológico (Ybf) e a produtividade real média (Yavg) de colmos no Brasil, para, posteriormente, determinar a quebra de produtividade da cana de açúcar decorrente do déficit hídrico (YGWD) e do manejo da cultura (YGCM), a fim de indicar estratégias para um cultivo mais sustentável. O modelo agrometeorológico de estimativa apresentou desempenho satisfatório na simulação das produtividades, tanto na fase de calibração como na validação. A produtividade estimada na calibração foi de 81.9 Mg ha-1 enquanto que a observada foi 82.3 Mg ha-1. Na validação, a produtividade estimada foi 82,9 Mg ha-1 e a observada foi 86,9 Mg ha-1. Esses resultados sugerem a possibilidade do emprego desse modelo para a estimativa da produtividade da cultura da cana-de-açúcar, principalmente em termos de planejamento agrícola em média e grande escalas. O sistema NASA/POWER apresentou desempenho satisfatório em relação às variáveis meteorológicas que controlam a Yp (radiação solar e temperatura do ar). Por outro lado, embora os totais anuais de precipitação tenham sido bastante semelhantes, a precipitação apresentou coeficientes estatísticos apenas razoáveis, principalmente para aplicações em modelos de simulação da produtividade (R2 = 0,60 e MAPE = 233,4%), sendo sugerido, portanto, o uso de dados dessa variável provenientes de estações pluviométricas locais. Na grande maioria dos locais avaliados o erro percentual da produtividade potencial variou entre ±15%, enquanto que a produtividade atingível foi superestimada em 14% quando esta foi estimada com os dados de precipitação do sistema NASA/POWER. Por outro lado, quando os dados de precipitação foram modificados pelos dados de estações pluviométricas da ANA, houve apenas 5% de superestimativa da produtividade. Por fim, foram geradas 259 estações meteorológicas virtuais com os dados do sistema NASA/POWER e a precipitação das estações pluviométricas da ANA. Posteriormente, os yield gaps por efeito do déficit hídrico e do manejo da cultura foram determinados. Os resultados indicaram que o principal fator restritivo da produtividade da cana de açúcar no Brasil é o déficit hídrico (74% do YG total), enquanto que as práticas de manejo da cultura sub-ótimas contribuem com 26% da quebra total. Isso contribuiu para um melhor entendimento dos aspectos que afetam a produção de cana de açúcar em diferentes regiões brasileiras, sendo, portanto, possível se delimitar estratégias, como o uso de cultivares tolerantes à seca, a irrigação e a descompactação dos solos, que tornem a cultura mais resiliente e produção canavieira mais eficiente e sustentável.

Concerns about global warming and climate change have triggered a growing demand for renewable energy. In this scenario, the interest in using sugarcane straw as raw material for energy production has increased. However, straw plays an important role in maintaining soil quality. In addition, uncertainties as to produced straw amount and the straw removal impact on the stalk yield have raised doubts as to the use this raw material. In this sense, the objective this study was evaluate the short-term (2-year) the sugarcane straw removal impacts on soil and yield modeling of sugarcane stalk and straw, using soil attributes of different layers. Two experiments were carried out in São Paulo state, Brazil: one at Capivari (sandy clay loam soil) and another at Valparaíso (sandy loam soil). We have tested five rates of straw removal (i.e., equivalent to 0, 25, 50, 75 and 100 %). Soil samples were taken from 0-2.5, 2.5-5, 5-10, 10-20 and 20-30 cm layers to analyze pH, total C and N, P, K, Ca, Mg, bulk density and soil penetration resistance. Plant samples were collected to determine the straw and stalk yield. The impacts caused by straw removal differed between the areas, however, they concentrated on the more soil superficial layer. In sandy clay loam soil, straw removal led to organic carbon depletion and soil compaction, while in the sandy loam soil the chemical attributes (i.e. Ca and Mg contents) were the most impacted. In general, the results suggest that straw removal causes reduction more significant in soil quality for the sandy clay loam soil. The results indicate the possibility to remove about half-straw amount deposited on soil\'s surface (8.7 Mg ha-1 straw remaining) without causing severe implications on the quality of this soil. In contrast, although any amount of straw was sufficient to cause alterations the quality of the sandy loam soil, these impacts were less intense and are not magnified with the increase of straw removal. It was possible to model sugarcane straw and stalk yield using soil attributes. The 0-20 cm layer was the most important layer in the stalk yield definition, whereas the 0-5 cm layer, which the impacts caused by the straw removal were concentrated, was less important. Thus, we noticed that impacts caused to soil by straw removal have little influence on crop productivity. Straw prediction has proved more complex and possibly requires additional information (e.g crop and climate information) for good results to be obtained. Overall, the results suggest that the planned removal of straw for energy purposes can occur in a sustainable way, but should take into account site conditions, e.g soil properties. However, long-term research with different approaches is still necessary, both to follow up and confirm our results, and to develop ways to reduce damage caused by this activity.
Preocupações acerca do aquecimento global e mudanças climáticas tem provocado uma crescente demanda por energias renováveis. Nesse cenário, tem aumentado o interesse em utilizar a palha de cana-de-açúcar como matéria prima para produção de energia. Contudo, a palha desempenha importante papel na manutenção da qualidade do solo. Aliado a isso, incertezas quanto a quantidade de palha produzida e o impacto da remoção da palha na produção de colmos tem levantado duvidas quanto ao uso dessa matéria prima. Nesse sentido, o objetivo desse estudo foi avaliar a curto prazo (2 anos) os impactos da remoção da palha de cana-de-açucar no solo, e modelar a produção de palha e colmo de cana-de-açucar utilizando atributos do solo de diferentes camadas. Para tanto, foram conduzidos dois experimentos nos municípios de Capivari (solo de textura média) e Valparaíso (solo de textura arenosa), estado de São Paulo, Brasil. Foram testados cinco taxas de remoção de palha (i.e., equivalentes a 0, 25, 50, 75 e 100 %). Amostras de solo foram coletadas nas camadas 0-2,5, 2,5-5, 5-10, 10-20 e 20-30 cm de profundidade para determinação de C, N, pH, P, K, Ca, Mg, densidade do solo e resistência do solo a penetração. Amostras de planta foram coletadas para determinar a produção de colmo e palha. Os impactos causados pela remoção da palha diferiu entre as áreas, no entato, se concentraram na camada mais superficial do solo. No solo de textura média a remoção da palha levou a depleção do carbono orgânico e a compactação do solo, enquanto que, no solo de textura arenosa os atributos químicos (i.e teores de Ca e Mg) foram os mais impactados. Os resultados indicam a possibilidade de remover cerca de metade da quantidade de palha depositada sobre o solo (8.7 Mg ha-1 palha remanecente) sem causar graves implicações na qualidade deste solo. Em contraste, no solo de textura arenosa, qualquer quantidade de palha foi suficiente para causar alterações na qualidade do solo, contudo, essas alterações foram menos intensas e não aumentaram com as taxas de remoção da palha. Foi possível modelar a produção de colmo e palha de cana-de-açucar utilizando atributos do solo. A camada 0-20 cm foi a mais importante na definição da produção de colmos, ao passo que a camada 0-5 cm, camada em que se concentra os impactos causados pela remoção da palha, foi menos importante. Assim, notamos que os impactos causados ao solo pela remoção da palha tem pouca influencia na produtividade da cultura. A predição da palha se mostrou mais complexa e possivelmente requer informações adicionas (e.g informações da cultivar e de clima) para que bons resultados sejam obtidos. No geral, os resultados sugerem que a remoção planejada da palha para fins energéticos pode ocorre de maneira susutentável, porém deve levar em conta condições locais, e.g propriedades do solo. Contudo, pesquisas de longo prazo com diferentes abordagens ainda são necessárias, tanto para acompanhar e confirmar nossos resultados, como para desenvolver soluções que atenuem os danos causados por esta atividade.

Sugarcane bacilliform virus (SCBV) is an economically important pathogen of sugarcane in Australia which limits access to foreign sugarcane germplasm. Although SCBV is present in the major cane growing regions worldwide, very little is known about its variability, virulence and the yield losses resulting from infection. The limited information on SCBV has resulted in quarantine measures being introduced to protect the Australian sugarcane industry, with a major consequence being restricted access to imported sugarcane germplasm for breeding programs. Foreign sugarcane germplasm plays an important role in breeding of new commercial varieties for the Australian sugar industry and is essential for the long term productivity, profitability and sustainability of the sugar industry. This study was aimed at characterising Australian isolates of SCBV to enable the development of reliable and robust molecular and/or antibody-based diagnostic tests which could be used to not only assess the impact of SCBV on the Australian sugarcane industry, but could also be used to screen imported sugarcane germplasm for the virus. SCBV virions (SCBV-IM) were purified from the sugarcane accession "Ireng Maleng" and the dsDNA genome was cloned and sequenced. The genome of SCBV-IM comprised 7687 bp with an organisation typical of other badnaviruses. When the entire nucleotide sequence of SCBV-IM was compared to that of the Moroccan SCBV isolate (SCBV-Mo), less than 75% similarity was present. Within the coding regions, ORF I, ORF II and ORF III had 83%, 71% and 73% nucleotide similarity to SCBV-Mo, respectively. At the amino acid level, ORFs I, II and III from SCBV-IM showed 91%, 84% and 85% similarity to the equivalent regions in SCBV-Mo, respectively. To further investigate the level of sequence variability within Australian SCBV isolates, virions were purified from three further sugarcane accessions and a 220 bp fragment of the reverse transcriptase-coding region was amplified. Five clones from each sub-population were selected and sequenced. Analysis of these sequences revealed considerable variability in the virus population with variability within one plant as great as it was between isolates. However, since the use of specific primers could also be selecting for a sub-population of SCBV sequences, it was possible that the variability may actually be greater than that reported. These results indicated that SCBV isolates are complex and variable and may represent a continuum of genetic variability. High molecular weight DNA species larger than the SCBV 7.6 kbp unit-length genome were found in DNA extracted from purified SCBV-IM virions. We confirmed that these high molecular weight nucleic acids were virus-specific and open circular in conformation. Using field inversion gel electrophoresis (FIGE), the SCBV-IM DNA was separated into four discrete bands with sizes ranging from between 1 to 4 genome copies. The DNA was shown to comprise overlapped individual genome-length molecules and not covalently-bonded continuous DNA strands. We presume that these DNA molecules are concatamers formed during replication as a result of a terminal overlap on the sense strand. The presence of these concatamers within virions may explain the observation of particles with lengths corresponding to one, two or three times the modal length of 130 nm. Four SCBV-infected Saccharum officinarum plants were examined for the presence of integrated viral DNA. Southern blot analysis of viral DNA and total DNA extracted from the same plant source were compared with, or without, restriction digestion. The resulting restriction patterns from viral and total DNA were almost identical suggesting that there were no integrated SCBV sequences in the sugarcane cultivars tested. Although larger-than-single-genome copy bands were detected in both the viral and the total DNA samples, this was probably due to the presence of genomic concatamers. SCBV integration studies using Southern analyses were further complicated by high sequence variability which precluded the restriction digestion of all viral DNA species. As such, some of the SCBV DNA species remain as concatamers which appear as larger-than-unit-length SCBV products. An antiserum derived from a mixture of purified SCBV isolates has been used routinely in the past to screen for SCBV infection, but the heterogeneity reported for badnaviruses has cast doubt on the ability of this antiserum to detect all SCBV isolates. We attempted to determine whether antiserum generated against proteins other than the viral capsid could be used to detect SCBV infections, thus improving the reliability and robustness of SCBV diagnosis. The complete coding regions of SCBV ORF I and ORF II were bacterially expressed and used as antigens for antiserum production. Both ORF I and II proteins were found to be highly immunogenic and generated high-titre antisera, designated AS-I and AS-II, respectively. The diagnostic utility of both antisera to detect SCBV in six different infected sugarcane plants was tested using both immunosorbent electron microscopy (ISEM) and western blots. The currently used SCBV antiserum (AS-V), generated against a mixture of purified SCBV isolates, was included for comparison. In western analyses, neither AS-I nor AS-V was able to conclusively detect SCBV in any of the six infected plants due to reactivity with numerous non-specific proteins. In contrast, AS-II reacted specifically with a protein of the expected size (~13.5 kDa) in 2/6 infected plants. When compared using ISEM, AS-V, AS-I and AS-II trapped virions from 6/6, 6/6 and 2/6 SCBV-infected plants, respectively. However, the number of virions trapped using AS-V was approximately 30-fold more than that trapped using either AS-I or AS-II. These results highlight the variability between SCBV isolates and suggest that ISEM with antisera raised against mixtures of viral proteins may be a useful tool for the detection of viral isolates.

Sugarcane bacilliform virus (SCBV) is an economically important pathogen of sugarcane in Australia which limits access to foreign sugarcane germplasm. Although SCBV is present in the major cane growing regions worldwide, very little is known about its variability, virulence and the yield losses resulting from infection. The limited information on SCBV has resulted in quarantine measures being introduced to protect the Australian sugarcane industry, with a major consequence being restricted access to imported sugarcane germplasm for breeding programs. Foreign sugarcane germplasm plays an important role in breeding of new commercial varieties for the Australian sugar industry and is essential for the long term productivity, profitability and sustainability of the sugar industry. This study was aimed at characterising Australian isolates of SCBV to enable the development of reliable and robust molecular and/or antibody-based diagnostic tests which could be used to not only assess the impact of SCBV on the Australian sugarcane industry, but could also be used to screen imported sugarcane germplasm for the virus. SCBV virions (SCBV-IM) were purified from the sugarcane accession "Ireng Maleng" and the dsDNA genome was cloned and sequenced. The genome of SCBV-IM comprised 7687 bp with an organisation typical of other badnaviruses. When the entire nucleotide sequence of SCBV-IM was compared to that of the Moroccan SCBV isolate (SCBV-Mo), less than 75% similarity was present. Within the coding regions, ORF I, ORF II and ORF III had 83%, 71% and 73% nucleotide similarity to SCBV-Mo, respectively. At the amino acid level, ORFs I, II and III from SCBV-IM showed 91%, 84% and 85% similarity to the equivalent regions in SCBV-Mo, respectively. To further investigate the level of sequence variability within Australian SCBV isolates, virions were purified from three further sugarcane accessions and a 220 bp fragment of the reverse transcriptase-coding region was amplified. Five clones from each sub-population were selected and sequenced. Analysis of these sequences revealed considerable variability in the virus population with variability within one plant as great as it was between isolates. However, since the use of specific primers could also be selecting for a sub-population of SCBV sequences, it was possible that the variability may actually be greater than that reported. These results indicated that SCBV isolates are complex and variable and may represent a continuum of genetic variability. High molecular weight DNA species larger than the SCBV 7.6 kbp unit-length genome were found in DNA extracted from purified SCBV-IM virions. We confirmed that these high molecular weight nucleic acids were virus-specific and open circular in conformation. Using field inversion gel electrophoresis (FIGE), the SCBV-IM DNA was separated into four discrete bands with sizes ranging from between 1 to 4 genome copies. The DNA was shown to comprise overlapped individual genome-length molecules and not covalently-bonded continuous DNA strands. We presume that these DNA molecules are concatamers formed during replication as a result of a terminal overlap on the sense strand. The presence of these concatamers within virions may explain the observation of particles with lengths corresponding to one, two or three times the modal length of 130 nm. Four SCBV-infected Saccharum officinarum plants were examined for the presence of integrated viral DNA. Southern blot analysis of viral DNA and total DNA extracted from the same plant source were compared with, or without, restriction digestion. The resulting restriction patterns from viral and total DNA were almost identical suggesting that there were no integrated SCBV sequences in the sugarcane cultivars tested. Although larger-than-single-genome copy bands were detected in both the viral and the total DNA samples, this was probably due to the presence of genomic concatamers. SCBV integration studies using Southern analyses were further complicated by high sequence variability which precluded the restriction digestion of all viral DNA species. As such, some of the SCBV DNA species remain as concatamers which appear as larger-than-unit-length SCBV products. An antiserum derived from a mixture of purified SCBV isolates has been used routinely in the past to screen for SCBV infection, but the heterogeneity reported for badnaviruses has cast doubt on the ability of this antiserum to detect all SCBV isolates. We attempted to determine whether antiserum generated against proteins other than the viral capsid could be used to detect SCBV infections, thus improving the reliability and robustness of SCBV diagnosis. The complete coding regions of SCBV ORF I and ORF II were bacterially expressed and used as antigens for antiserum production. Both ORF I and II proteins were found to be highly immunogenic and generated high-titre antisera, designated AS-I and AS-II, respectively. The diagnostic utility of both antisera to detect SCBV in six different infected sugarcane plants was tested using both immunosorbent electron microscopy (ISEM) and western blots. The currently used SCBV antiserum (AS-V), generated against a mixture of purified SCBV isolates, was included for comparison. In western analyses, neither AS-I nor AS-V was able to conclusively detect SCBV in any of the six infected plants due to reactivity with numerous non-specific proteins. In contrast, AS-II reacted specifically with a protein of the expected size (~13.5 kDa) in 2/6 infected plants. When compared using ISEM, AS-V, AS-I and AS-II trapped virions from 6/6, 6/6 and 2/6 SCBV-infected plants, respectively. However, the number of virions trapped using AS-V was approximately 30-fold more than that trapped using either AS-I or AS-II. These results highlight the variability between SCBV isolates and suggest that ISEM with antisera raised against mixtures of viral proteins may be a useful tool for the detection of viral isolates.

An in vitro method for the establishment and storage of over 200 Saccharum spp. hybrid clones was developed that involved only 1 medium for shoot development and multiplication, without decontamination procedures. Apical buds from the axils of developing leaves surrounding the apical meristem were cultured on medium containing the plant growth regulators benzylamino purine and kinetin which regenerated multiple shoots. Shoots transferred to a medium containing naphthalene acetic acid and 60 g L"1 sucrose, developed roots. In vitro plants were transferred to a half strength Murashige and Skoog medium without plant growth regulators and placed in storage at 18°C. After 12 months of storage plants were transferred to a fresh medium and returned to storage. The genetic integrity of clones based on phenotypic assessment and isozyme patterns was not affected by in vitro culture after 3, 6 and 12 months storage at l 8°C.

Dissertation (PhD) -- University of Stellenbosch, 2002.
ENGLISH ABSTRACT: Sugarcane (Saccharum spp. hybrids) is a commercial crop plant capable of storing up to 20% sucrose on a fresh mass basis in the culm. Knowledge about gene expression during sugarcane growth and maturation is limited. The aim of this study was to assess whether an Expressed Sequence Tag (EST)-based approach towards analysis of sugarcane would reveal new information about gene expression and metabolic processes associated with sugarcane growth and development. The specific objectives were two-fold: firstly, to develop an EST database for sugarcane and secondly, to identify and analyse genes that are expressed in different sugarcane tissue types and developmental stages, with a specific focus on leaf and culm. An EST database for sugarcane was initiated to obtain information on sugarcane gene sequences. A total cDNA library was constructed from sugarcane immature leaf (leaf roll: meristematic region) tissue and 250 clones randomly selected and subjected to single-pass DNA sequence analysis. Sugarcane ESTs were identified by sequence similarity searches against gene sequences in international databases. Of the 250 leaf roll clones, 26% exhibited similarity to known plant genes, 50% to non-plant genes while 24% represented new gene sequences. Analysis of the identified clones indicated sequence similarity to a broad diversity of genes. A significant proportion of genes identified in the leaf roll were involved in processes related to protein synthesis and protein modification, as would be expected in meristematic tissues. Submission of 495 sugarcane gene sequences to the dbEST database represented the first sugarcane ESTs released into the public domain. Two subtracted cDNA libraries were constructed by reciprocal subtractive hybridisation between sugarcane immature and maturing internodal tissue. To explore gene expression during sugarcane culm maturation, partial sequence analysis of random clones from maturing culm total and subtracted cDNA libraries was performed. Database comparisons revealed that of the 337 cDNA sequences analysed, 167 showed sequence homology to gene products in the protein databases while 111 matched uncharacterised plant ESTs only. The remaining cDNAs showed no database match and could represent novel genes. The majority of ESTs corresponded to a variety of genes associated with general cellular metabolism. ESTs homologous to various stress response genes were also well represented. Analysis of ESTs from the subtracted library identified genes that may be preferentially expressed during culm maturation. The expression patterns of sugarcane genes were examined in different tissue sources and developmental stages to identify differentially expressed genes. cDNA arrays containing 1000 random clones from immature leaf and maturing culm cDNA libraries were hybridised with poly (At RNA from immature leaf, mature leaf, immature culm and maturing culm. All cDNAs examined hybridised to all four probes, but differences in signal intensity were observed for individual cDNAs between hybridisation events. No cDNAs displaying tissue- or developmental-stage specific expression were detected. Comparisons between hybridisation patterns identified 61 cDNAs that were more abundantly expressed in immature and mature leaf than the culm. Likewise, 25 cDNAs preferentially expressed in immature and maturing culm were detected. ESTs established for the differentially expressed cDNAs revealed sequence homology to a diverse collection of genes in both the leaf and the culm. These included genes associated with general cellular metabolism, transport, regulation and a variety of stress responses. None of the differentially expressed genes identified in the culm were homologous to genes known to be associated with sucrose accumulation. To examme differences at the level of gene transcription between low sucroseaccumulating and high sucrose-accumulating tissues, subtracted cDNA libraries were utilised. To isolate cDNAs differentially expressed during culm maturation, cDNA arrays containing 400 random clones (200 from each library) were screened with total cDNA probes prepared from immature and maturing culm poly (At RNA. Results indicated that 36% and 30% of the total number of cDNAs analysed were preferentially expressed in the immature and maturing culm, respectively. Northern analysis of selected clones confirmed culm developmental stage-preferential expression for most of the clones tested. ESTs generated for the 132 differentially expressed clones isolated exhibited homology to genes associated with cell wall metabolism, carbohydrate metabolism, stress responses and regulation, where the specific ESTs identified in the immature and maturing culm were distinct from each other. No developmentally regulated ESTs directly associated with sucrose metabolism were detected. These results suggest that growth and maturation of the sugarcane culm is associated with the expression of genes for a wide variety of metabolic processes. In addition, genes encoding enzymes directly involved with sucrose accumulation do not appear to be abundantly expressed in the culm.
AFRIKAANSE OPSOMMING: Kommersiële suikerriet variëteite (Saccharum spp. hibriede) is in staat om tot 20% sukrose op 'n vars massa basis in die stingel op te berg. Kennis oor geenuitdrukking tydens groei en rypwording is beperk. Die doel van die huidige studie was om vas te stelof 'n grootskaalse karatersisering van die geenvolgordes wat uitgedruk word "Expressed Sequence Tag (EST)-based approach" tot nuwe inligting aangaande die aard en omvang van metabolisme tydens groei en ontwikkeling van suikerriet sal lei. 'n Tweeledige benadering is in hierdie studie gevolg. Eerstens is 'n data basis oor die gene wat uitgedruk word "EST" databasis opgestel. Tweedens is gene geïdentifiseer en gekarakteriseer wat spesifiek op verskillende stadiums van ontwikkeling en in spesifiek weefsel uitgedruk word. Vir die opstel van die EST-databasis is 250 klone uit 'n totale cDNA biblioteek vanaf RNA uit suikerrietblaarweefsel (blaarrol:meristematiese streek) op 'n lukraak basis gekies en aan 'n enkel eenrigting DNA volgorde analise onderwerp. Suikerrriet EST's is geïdentifiseer deur middel van homologie soektogte teen geenvolgordes in internasionale databasisse. Uit die 250 blaarrol klone het 26% ooreenkomste met bekende plant gene en, 50% met nie-plant gene getoon. Ongeveer 24% het nuwe geenvolgordes verteenwoordig. Analise van die geïdentifeseerde klone het ooreenkomste met 'n breë diversiteit van gene getoon. 'n Betekenisvolle gedeelte van gene wat in die blaarrol geïdentifiseer is, is by proteïensintese en proteïenmodifikasies betrokke. Dit is in ooreenstemming met wat van meristematiese weefsel verwag kan word. Die 495 suikerriet geenvolgordes wat in die internasionale dbEST databasis gestort is, is die eerste sodanige inligting in die publieke domein. Twee spesifieke cDNA biblioteke (subtraction libraries) wat volgordes spesifiek aan onvolwasse suikerriet en rypwordende internodale weefsel bevat is voorberei. Geenuitdrukking gedurende die rypwordingsproses van die suikerrietstingel is bestudeer deur geenvolgorde analises van onwillekeurige geselekteerde klone van die twee eDNA biblioteke te doen. Van die 337 geenvolgordes wat geanaliseer is het 167 homologie met bekende gene en net 111ooreenkomste met ongekarakteriseerde plant gene getoon. Die oorblywende geenvolgordes het geen ooreenkomste met bekende gene getoon nie en daar kan dus aanvaar word dat hulle nuwe gene verteenwoordig. Die meerderheid ESTs het ooreenkomste met verskeie gene wat met sellulêre metabolisme geassosieer word getoon. ESTs wat homoloog was aan verskeie spannings geassosieerde gene was ook goed verteenwoordig. Die analise het gene wat by voorkeur tydens stringelrypwording uitgedruk word geidentifiseer. Die geenuitdrukkingspatrone van suikerriet in weefsels van verskillende oorsprong en ontwikkelingstadia is ondersoek om differensieel uitgedrukte gene te identifiseer. Reekse wat 1000 lukrake eDNA klone van onvolwasse en rypwordende stingel eDNA biblioteke is met poli-(A)-RNA van onvolwasse blaar, volwasse blaar, onvolwasse stingel en volwasse stingel gehibridiseer. Al die eDNA klone wat ondersoek is het met al vier die peilers gehibridiseer. Die intensiteit van die seine het egter grootliks gevarieer. Die analise het gelei tot die identifisering van 61 eDNA klone wat teen hoër vlakke in onvolwasse en volwasse blaar as in die stingel uitgedruk word. Daar is ook 25 eDNA klone wat by voorkeur in onvolwasse en rypwordende stingel uitgedruk word gevind. Gene wat geassosieer word met gewone sel metabolisme, vervoer prosesse, regulering en verskeie spannings-geassosieerde reaksies, is in die twee groepe teenwoordig. Geeneen van die volgordes wat selektief uitgedruk word kan met gene wat direk met sukrose akkumulering verband hou geassosieer word nie. Ten einde eDNA klone wat differensieel tydens rypwording van die stingel uitgedruk word te isoleer, is 400 eDNA klone (200 van elke biblioteek) lukraak geselekteer en met totale eDNA peilers, wat uit onvolwasse en rypwordende stingel poli-(A)-RNA voorberei is, gesif. Resultate het aangetoon dat 36% en 30% van die totale getal eDNA klonewat geanaliseer is, by voorkeur in die onvolwasse en rypwordende stingel uitgedruk word. RNA kladanalises van geselekteerde klone het getoon dat die meeste ontwikkelingstadium spesifieke uirtdrukkingspatrone het. Daar is gevind dat 132 van die EST klone homologie met gene geassosieerd met selwand- en koolhidraatmetabolisme, spannings geassosieerde- en reguleringsreaksies, toon. Die spesifieke ESTs wat in die onvolwasse en rypwordende stingel geïdentifiseer is het van mekaar verskil. Nie een van die ESTs wat geïdentifiseer is kan direk met sukrose metabolisme geassosieer word nie. Hierdie werk toon baie duidelik aan dat groei en rypwording van die suikerrietstingel met die uitdrukking van gene geassosieerd is wat by 'n hele aantal metaboliese prosesse betrokke is. Die resultate toon ook dat die gene wat vir ensieme kodeer wat direk by sukrose akkumulering betrokke is, nie teen hoë vlakke in die stingel uitgedruk word nie.