Dissertations / Theses on the topic 'Straw barley'

Abstract Biomass conversion methods represent bioeconomic solutions for the sustainable production of value added commodities (chemicals and materials) as well as for energy purposes, either in solid (pellets), liquid (transport fuels) or gaseous (combustion gases e.g. biomethane) form. Lignocellulosic biomass as a renewable source available in immense quantity, is considered to be one of the most promising natural sources, with high potential in the replacement of conventional transportation fuels and reduction of greenhouse gas emissions. This thesis provides new insights into mechanocatalysis, which as yet is a novel technique in catalytic biomass conversion. The mechanocatalytic approach combines chemical catalysis and mechanical assisted processing driven by ball milling. Lignocellulosic barley straw was impregnated or merely mixed with the catalyst (formic acid, acetic acid, sulfuric acid, oxalic acid dihydrate and potassium pyrosulfate) and ball milled under various conditions yielding the selective depolymerization of lignocellulose into water-soluble xylo-oligosaccharides. Subsequent hydrolysis at moderate temperatures resulted in the formation of valuable reducing sugars, mainly xylose, galactose, arabinose and glucose, which constitute the basic materials for transportation fuel and chemical production. Reducing sugar release of 53.4 wt% with low by-product formation was observed within short milling durations using sulfuric acid as a catalyst in mechanocatalysis. Likewise, oxalic acid dihydrate and potassium pyrosulfate as a novel catalyst, successfully converted barley straw to reducing sugars (42.4 wt% and 39.7 wt%, respectively), however longer milling durations were required. In comparison, lower saccharification (<10 wt%) was obtained by employing formic acid and acetic acid in mechanocatalysis. Harsh milling conditions initiated a temperature increase within the reaction vessel resulting in enhanced sugar release. Likewise, greater sugar release was observed with increased catalyst amount and acidity. The results revealed that the balance of these factors is crucial for efficient catalytic conversion of barley straw
Tiivistelmä Biomassan konvertointimenetelmät mahdollistavat biotalouden hengen mukaisesti uusia ratkaisuja kemikaalien ja materiaalien kestävään tuotantoon sekä biomassan energiakäyttöön eri muodoissa (kuten pelletit, biopolttoaineet ja biokaasu). Lignoselluloosapohjaista, uusiutuvaa biomassaa, kuten tässä työssä tutkittua ohran olkea, on runsaasti saatavilla. Lignoselluloosa onkin yksi lupaavimmista raaka-aineista korvaamaan fossiilisia polttoaineita ja vähentämään kasvihuonekaasupäästöjä. Väitöskirjatutkimus antaa uutta tietoa ohran oljen mekaanis–katalyyttisestä käsittelystä, mikä on suhteellisen uusi menetelmä biomassan katalyyttisessä muokkauksessa. Menetelmässä yhdistetään kemiallinen katalyysi ja mekaaninen muokkaus (jauhatus) kuulamyllyllä. Lignoselluloosa (ohran olki) impregnoitiin tai sekoitettiin tutkitun katalyytin (muurahaishappo, etikkahappo, rikkihappo, oksaalihappodihydraatti, kaliumpyrosulfaatti) kanssa ja käsiteltiin erilaisissa mekaanis–katalyyttisissä olosuhteissa. Lignoselluloosan selektiivinen depolymerointi muodosti vesiliukoisia oligosakkarideja ja edelleen hydrolyysin kautta pelkistyneitä sokereita (pääasiassa ksyloosia, galaktoosia, arabinoosia ja glukoosia), joita voidaan käyttää biopolttoaineiden ja -kemikaalien valmistuksessa. Tutkimuksen tulosten perusteella rikkihappokatalyytillä saatiin 53,4 massa-% ohran oljen sisältämistä pelkistyneistä sokereista vapautettua lyhyillä käsittelyajoilla. Lisäksi sivutuotteiden muodostuminen oli vähäistä. Vastaavasti oksaalihappodihydraatti (sokerisaanto 42,4 massa-%) ja kaliumpyrosulfaatti (sokerisaanto 39,7 massa-%) toimivat uusina katalyytteinä hyvin, mutta vaativat rikkihappokatalyyttiä pidemmät jauhatusajat. Sen sijaan muurahaishapolla ja etikkahapolla sokerisaanto oli erittäin alhainen (alle 10 massa-%) mekaanis–katalyyttisessä käsittelyssä. Tutkimuksessa todettiin, että voimakas jauhatus vaikutti selkeästi reaktiolämpötilan nousuun käsittelyn aikana, mikä edisti korkeampaa sokerisaantoa. Vastaavasti sokerisaantoa voitiin parantaa katalyyttimäärällä ja happamuudella. Tulokset osoittavat, että näiden muuttujien tasapaino on ratkaisevaa ohran oljen tehokkaan katalyyttisen muuntamisen kannalta

Barley straw, an agricultural byproduct, was identified as a potential adsorbent material for wastewater treatment as it offers various advantages such as abundant availability at no or very low cost, little processing cost and ability to biodegradation. The raw barley straw, however, needs to be modified as a preliminary study showed less favorability of the raw barley straw in removing oil and anionic dyes. Barley straw was chemically pretreated with sodium hydroxide and modified using a cationic surfactant, hexadecylpyridinium chloride monohydrate (CPC).Generally, the treatment with NaOH increases the negatively charged sites on straw surface and the cationic surfactant introduced forms a hydrophobic layer on the straw surface and changes the surface potential charge from negative to positive. From this exercise, four different adsorbents have been prepared, viz; raw barley straw (RBS), raw barley straw pretreated with sodium hydroxide (RBS-N), and the modification of RBS and RBS-N with the cationic surfactant CPC, which were labelled as surfactant modified barley straw (SMBS) and base pretreated surfactant modified barley straw (BMBS).Several physical and chemical techniques were employed to characterize barley straw samples to understand the properties of raw and modified straws as well as to study the effects of modification on the textural and surface properties of the raw barley straw. Chemical compositional analyses showed that the amounts of potassium, sodium, arsenic and cadmium existing in RBS, RBS-N were generally low. The availability of cellulose, hemicellulose and lignin in RBS offers the great potential of using the barley straw as a biosorbent material. Surface group measurement by the Boehm titration showed higher acid groups in the base-treated straw (RBS-N) than raw straw due to the base hydrolization of lignocellulosic material, which is responsible for the increase in surface acidic sites such as carboxylic and hydroxyl groups.The percentages of carbon and nitrogen for SMBS and BMBS were greater compared to RBS and RBS-N, due to loading of CPC. Based on carbon and nitrogen values, the impregnated CPC on SMBS and BMBS was calculated as 0.086 and 0.109 mmol g-1, respectively. For the surfactant modified straw, lower BET surface area was observed and could be explained by the attachment of the surfactant moieties to the internal framework of raw adsorbents causing the constriction of pore channels. The electrical conductivity was found much lower in surfactant modified straw due to significant reduction in water soluble mineral after the surfactant modification. Higher bulk density of SMBS and BMBS was due to the addition of CPC onto the straw surface. SEM microphotos of all the prepared adsorbents showed the highly irregular shapes and sizes.The treatment with alkaline solution partly removed the protective thin wax on straw surface. The surfactant modified surface appeared to be rough, indicating that the surface had been covered with organic molecules. FT-IR spectra of RBS and RBS-N did not show any radical changes indicating that the treatment with mild base solution did not significantly alter the chemical properties of the straw. Two new bands lying at about 2920, 2850 cm-1 referred as asymmetric and symmetric stretching vibration of methylene (C-H) adsorption bands originated from the alkyl chain of CPC were observed on SMBS and BMBS, proving the existence of CPC on straw surface. Desorption of CPC from the surfactant modified straw was observed to increase with increasing acid solution concentration. The increasing desorption of CPC (with increased in acid solution) describes that ion exchange is the major binding mechanism. The sorption of CPC generally showed that the sorption capacity of CPC increases with increasing CPC equilibrium concentration for both RBS and RBS-N. The surfactant sorption was at the maximum when the equilibrium surfactant concentrations reached the critical micelle concentration, CMC.Preliminary experiments found the effectiveness of the prepared adsorbents, namely; RBS, RBS-N, SMBS and BMBS in removing different types of emulsified oil from wastewater such as canola oil (CO) and standard mineral oil (SMO). Comparing to SMBS and BMBS, RBS and RBS-N showed low removal efficiency of the emulsified oil. This provided a sensible justification in using SMBS and BMBS as adsorbent materials. The adsorption tests were performed using SMBS and BMBS on CO and SMO by batch adsorption. For the sorption of CO and SMO on SMBS and BMBS, the adsorption was less favorable at high acidic condition and the maximum adsorption capacity was observed at about neutrality. Larger particle size would result in lower adsorption while adsorption temperature would not affect adsorption significantly.The kinetic study revealed that equilibrium time was short and pseudo first order model provided the best correlation for the kinetic adsorption data of CO and SMO on both SMBS and BMBS. The film diffusion was observed as the rate limiting in the sorption of CO and SMO on SMBS and BMBS. The isotherm data for sorption of CO and SMO on SMBS and BMBS indicated that the adsorption was fitted well by the Langmuir model. The Langmuir adsorption capacities of CO and SMO on SMBS were 576.00 and 518.63 mg g-1; and 613.29 and 584.22 mg g-1 on BMBS, respectively. Desorption experiments also showed the stability of the oil loaded on straw. The adsorbent was later evaluated in a fixed bed column. The breakthrough curves indicated the favorable performance of SMBS and BMBS for both CO and SMO; however, less success was observed for RBS and RBS-N. The modeling of column tests showed a good agreement of experimental data of oil adsorption on SMBS and BMBS with the Thomas and Yoon-Nelson models. The column adsorption capacities from the Thomas model for SMBS and BMBS were 368.82 and 440.74 mg g-1 for CO; and 310.16 and 336.31 mg g-1 for SMO, respectively.The applicability of the prepared adsorbents was also evaluated for treating dye containing wastewater. The adsorption tests were performed using SMBS and BMBS on anionic dyes of Acid Blue 40(AB40), Reactive Blue 4(RB4) and Reactive Black 5(RB5) as the preliminary batch adsorption experiments showed low removal percentage of dyes on RBS and RBS-N. The batch study also revealed that the adsorption was a function of dye concentration, pH and temperature. Adsorption capacity was found higher at pH about neutrality for AB40, and at acidic condition (pH 3) for the other dyes. Adsorption capacity of AB40 increased at increasing experimental temperature whereas no significant change was observed for RB4 and RB5. The kinetic experiment revealed that adsorption of dyes was rapid at initial stage followed by a slower phase where equilibrium uptake was achieved. Based on batch kinetic study of adsorption of AB40, RB4 and RB5 on SMBS and BMBS, the pseudosecond- order model fitted well with the kinetic data other than the pseudo first order model.The film diffusion was observed as the rate limiting in the sorption of AB40, RB4 and RB5 on SMBS and BMBS. The isotherm data of dye adsorption on SMBS and BMBS indicated that the adsorption was fitted well by the Langmuir model. The Langmuir adsorption capacities of AB40, RB4 and RB5 were 45.4, 29.16 and 24.92 mg g-1 for SMBS and 51.95, 31.50 and 39.88 mg g-1 for BMBS, respectively.Desorption experiments also showed that the dye loaded straw was stable at acidic condition but desorption increased as the pH increased (i.e pH 11). The applicability of the adsorbents for AB40 and RB5 removal was also tested in a fixed bed column study. Similar to the column system for CO and SMO, the breakthrough curves on RBS and RBS-N was also poor, however, favorable column breakthrough performance was observed on SMBS and BMBS. The column breakthrough modeling showed the better fit of the experimental data of SMBS and BMBS with the Thomas and Yoon-Nelson breakthrough models. The adsorption capacities from the Thomas model for SMBS and BMBS were estimated as 53.39 and 77.29 mg g-1 for AB40; and 24.57 and 33.46 mg g-1 for RB5, respectively.

Algal and cyanobacterial1 blooms are increasingly becoming a problem to water utilities in the UK and around the world. Conditions such as increasing eutrophication and poor management of water bodies are consequently leading to increases in the number and severity of algal bloom events. These blooms present serious issues to both utilities and the environment; problems include deoxygentation of water bodies leading to fish kill and rapid algal growth leads to overgrowing of other plant species in the water, while blooms of toxic cyanobacteria can lead to the closure of reservoirs and a number of algae can lead to pump and filter blockages in treatment works. The problems created by algal and cyanobacterial blooms are becoming increasingly expensive to offset and while some technologies such as dissolved air flotation exist to control them at treatment level, there are few effective options to tackle blooms where control would be most effective, at the source. What methods there are for source control are often unreliable or almost as bad for the environment as the blooms themselves such as, in the use of chemical pesticides. Barley straw has been shown to have to potential to be an effective control of algal and cyanobacterial blooms at the reservoir level, being able to inhibit a variety of species at practical straw concentrations, but little is known about how it functions or how its ‘effect’ is developed. This study identified spcific areas which when investigated provided insight into these gaps in current knowledge. An analysis of the chemicals proposed as released by decaying barley straw has shown that they can control algal blooms at concentrations similar to what has been detected in the field. Investigations into the decay of barley straw has shown that barley straw decays in water in a way consistent with species that breakdown the lignin section of the straw potentially releasing the proposed chemicals. This finding was supported by the effect being consistent when field rotted straw, fresh straw rotted in the lab, and straw cultured in the lab with species specifically adapted to breaking down the lignin section of the straw were compared. Attempts at pre-treating the straw have shown that microbiological activity is important in developing the algistatic effect, which could lead to the possibility of keeping straw ‘ready for use’ thus removing the current need of several months wait before barley becomes effective. These findings have also provided a definitive route by which barley straw develops its effect, namely, microbiological decay of the lignin fraction of the straw leading to the production of phenol chemical release.

In the world today there is a massive dependency on fossil fuels as they are currently used to provide around 80% of the world’s energy. This is hugely detrimental to the environment and is a major contributory factor in climate change. Biofuel is a renewable energy source that is already being used to lessen some of the fossil fuel dependency. 2nd generation biofuels, by using non-food parts of plants, circumvent the food vs fuel argument, and by using farming waste or surplus can also avoid changing land use problems. Additionally liquid biofuels can use existing infrastructure for storage and delivery, and also fit into current lifestyles. Cost-effective 2nd generation biofuel production is directly affected by the presence of the polymer lignin in plant biomass, as it has been shown to impede enzymatic sugar release (saccharification) that is used for biofuel production. The work undertaken in this project developed a high-throughput methodology for the assessment of straw lignin content and composition across a large population of elite varieties in the economically important cereal crop, barley. Saccharification yield was also measured across the same population along with a number of other agronomically important traits, such as thousand-grain weight, biomass, mechanical stem properties and height. The data provided by these measurements allowed correlations between traits to be identified and their strength gauged. Genome wide association studies (GWAS) were also carried out and identified influential regions of the genome for each trait. The results revealed varying levels of association between measured traits and lignin content and monomeric constituents. Importantly a negative connection was shown between lignin content and saccharification yield, with lignin content being responsible for approximately 1/5th of the variation seen. Interestingly there was no correlation between lignin content and mechanical stem properties, an important factor in the agronomically important trait, lodging. GWAS results revealed a number of genomic regions that were influential across several traits indicating regions that would be difficult to separate through breeding due to their close proximities. However, unique QTL were identified for saccharification yield and lignin content providing candidates for breeding or genetic manipulation to improve the crop for biofuel production.

Experiments were conducted in Avra Valley, Arizona, to study the use of digested liquid sewage sludge as a source of plant nutrients in the commercial production of grain and straw from wheat. Wheat grown with the recommended amount of plant -available nitrogen from sewage sludge produced the same grain yield as wheat grown with the same amount of nitrogen from inorganic fertilizer. Wheat grain and straw grown with sewage sludge and inorganic fertilizer had similar livestock feeding qualities. Fertilizing wheat with sewage sludge delayed maturity.

The incorporation of cereal straw/stubble often immobilises nitrogen (N). This can help conserve N in soil in organic forms, thus reducing loss through leaching over dormant winter periods. However, N-depressions that arise during decomposition can reduce crop yield. The inclusion of a legume green manure can supply fixed-N, thus alleviating the low N availability to crops. In this study, the effect of lupin (Lupinus angustifolius L.) green manure incorporation on barley (Hordeum vulgare L.) straw/stubble decomposition, and N availability was investigated. A field experiment was used to determine the effects of the green manure on decomposition. Decomposition of straw/stubble was monitored using the litterbag technique. Following green manure incorporation, soil cores were incubated in a glasshouse to determine mineral-N availability. Though not significant, the inclusion of lupin green manure seemed to increase the decomposition of straw/stubble during the growth period, then slowing it after its incorporation at 110 d. This was described by a logarithmic pattern of loss of - 4.97 g AFDW residue day⁻¹, with 60% remaining after 140 d. Treatments without lupin had a linear decomposition of - 0.12 g AFDW residue day⁻¹, with 49% remaining after 140 d. The loss of cellulose confirmed the differences in decomposition with the inclusion of lupin resulting in 2.79% less cellulose remaining in straw/stubble after 140 d compared to its exclusion. Lupin significantly increased pot oat N uptake and DM yield by 55 % and 46 %, respectively, compared to its exclusion. However, this effect was not observed in field sown wheat yields and the soil mineral-N measurements made. This study showed that the potential of lupin to increase straw/stubble decomposition by improving the retention and availability of N, leading to long-term yield benefits, needed further investigation.

Cyanobacteria are present in most water bodies and sometimes grow to large populations known as blooms. Some of these cyanobacteria are also capable of producing toxins which can be fatal to livestock and humans. The production of cyanobacterial toxins is not specles-, but gene-specific, so the prediction of toxicity based on identification of the cyanobacteria using morphological characteristics is unlikely to be reliable. A better way to predict the likely toxicity of a bloom is the use of molecular techniques to detect the genes for toxin production and this was the approach taken in the first part of this project. This consisted of an analysis of . both cyanobacterial diversity and the occurrence of toxin genes in selected water bodies in Yorkshire. The mcyE gene, specific to some Microcystis sp. Anabaena sp. and Planktothrix sp. was found in plankton samples taken from the selected sites. The second part of the project was concerned with the use of rotting barley straw to inhibit cyanobacterial growth. Control of bloom formation using chemicals such as copper sulphate can have damaging environmental consequences but an alternative is the use of barley straw, the efficacy of which has been previously confirmed. Of the five newly-isolated cyanobacteria tested in this project, Microcystis strains 50053 and 50054, and Pseudanabaena strains 50055 and 50056 were markedly susceptible to straw inhibition, while Anabaena strain 50051 was susceptible, but to a much lesser degree. It was shown that prolonged incubation of sterile straw did not render it active at inhibiting the growth of the test cyanobacteria, conclusively demonstrating for the first time that straw activation requires microbial activity. This project was also the first to examine bacterial and fungal diversity on rotting barley straw and revealed a complex population of bacteria and fungi, many of which have the capacity for lignin degradation. This observation strengthens the evidence in support of the hypothesis that lignin derivatives released during the breakdown of straw may be responsible for inhibiting cyanobacterial growth.

N-methylmorpholine-N-oxide has shown a positive effect for the pretreatmentof lignocelluloses. Pretreatment by NMMO was developed to enhance thedigestibility of lignocellulosic biomass.Barely straw and forest residue were pretreated by N-methylmorpholine-Noxide(NMMO) prior to anaerobic digestion. The effectiveness of NMMOtreatmenton straw and forest residue was examined as well as the recycling andreuse of NMMO for the next pretreatment process. During the first experimentalseries pretreatments were performed at 90 °C for 3h and 30h, followed bydigestion of the pretreated material for 41 days. Low methane yield was found inthese experiments due to high organic loading rate. In the second series therecycling and reuse of NMMO was investigated on straw. The pretreatmentswere carried out at 90 °C for 30 hr and the recycling and reuse were performedin three times. After treatments with fresh, as well as 1, 2, 3 times recycledNMMO methane yield of 0.45, 0.42, 0.38 and 0.4 Nm3/kg VS were obtained.
Program: Masterutbildning i energi- och materialåtervinning - industriell bioteknik

The main objectives of the work described in this thesis were to determine the technical feasibility of utilising date palm leaves as a potential source of roughage, and to study the effects of providing brackish water as a source of drinking water for dairy cows. Additionally, to investigate the effect of feeding a high concentrate diet on the performance of Friesian cows. Four experiments were performed during the course of three years (November 1988 - June 1991). Three experiments were carried out in Kuwait and one in the North of Scotland. Experiment 1 was designed to compare the effects of feeding locally produced date palm leaves (DPL) with imported barley straw (S) as roughages to milking cows given a high concentrate diet. Fifty-six cows were used from the fifth week of lactation for 12 weeks. Experiment 2 studied the performance of thirty eight non-lactating pregnant cows for about 15 weeks, with the same objective as experiment 1. Each of these experiments included a small trial for more detailed studies. In experiment 3 eight milking cows in the sixth week of lactation were studied for over six months to compare the effects of drinking brackish water (BW) with fresh water (FW) on the performance of the cows fed on a high concentrate diet in addition to DPL and freshly cut alfalfa. Experiment 4 was conducted in the North of Scotland to investigate the effects of feeding a high concentrate diet, similar to that of Kuwait, on the productivity and the ruminal fermentation of high yielding cows. The general conclusions drawn from these four experiments are: 1. Despite the low qulaity of DPL, it might be a suitable alternative to straw as a source of roughage for dairy cows in Kuwait. 2. Brackish water is a palatable and harmless source of drinking water, and its mineral content may be beneficial in contributing to the dairy cows dietary requirements. 3. Feeding a high level of concentrate in diets based on grass silage increases milk yield and favours body gain at the expense of milk fat content. 4. There is a need for better utilization and processing of local agricultural by-products in Kuwait for the feeding of ruminants. 5. Further research is required to investigate the performance of dairy cows under different environments, especially hot-arid conditions.

Magistrantūros studijų baigiamajame darbe pateikiami pasėlio sudygimo, tankumo, piktžolėtumo tyrimo duomenys skirtingo intensyvumo žemės dirbimo, padengimo šiaudais ir žaliąja trąša laukeliuose. Stacionarus dviejų veiksnių eksperimentas vykdomas nuo 1999 metų. Tyrimai buvo vykdomi nuo 2011 - 2012 m. Eksperimentas buvo vykdomas pagal tokią schemą: A veiksnys: Šiaudų įterpimas: šiaudai pašalinti (-Š), šiaudai susmulkinti ir paskleisti (+Š). B veiksnys: Žemės dirbimo sistemos. Atlikus tyrimus nustatyta, kad miežių daigų skaičiui trečią dieną nuo dygimo pradžios esminės įtakos turėjo žemės dirbimo intensyvumas. Fone, kur šiaudai buvo susmulkinti ir paskleisti (+Š) esmingai didesnis daigų skaičius, palyginti su giliu arimu (GA), nustatytas laukeliuose, kurie buvo sekliai purenti kultivatoriumi plokščiapjūviais noragėliais ir lėkštiniais padargais (KL) ir laukeliuose su žaliąja trąša (ŽTRK). Fone be šiaudų (-Š), palyginus su giliu arimu (GA), esmingai daugiau miežių daigų sudygo sekliai artuose (SA), sekliai purentuose kultivatoriumi plokščiapjūviais noragėliais ir lėkštiniais padargais (KL) ir neįdirbtos ražienos (ND) laukeliuose. Dešimtąją dieną nuo dygimo pradžios, tiek fone su susmulkintais ir paskleistais šiaudais, tiek fone be šiaudų esmingai mažiau miežių daigų rasta laukeliuose, kurie buvo sekliai purenti rotoriniu kultivatoriumi (RK). Fone su šiaudais taip pat esminiai skirtumai nustatyti laukeliuose kur sėta į neįdirbtą ražieną (ND). Produktyvių stiebų skaičiui neturėjo... [toliau žr. visą tekstą]
Master's thesis presents data of a study of crop germination, density, weed and earthworm population in fields varying in intensity of tillage, straw and green fertilizer coverage. Stationary two-factor experiment is being carried out since 1999. Studies were carried out from 2011 – 2012 . The experiment was carried out according to the following scheme: factor A: Straw incorporation: straw removal (-Š), straw shredded and spread out (+ Š). Factor B: tillage systems. The research found that the number of barley sprouts on the third day from the beginning of germination is essentially influenced by tillage intensity. In area, where the straw were chopped and spread (+Š) substantially increased the number of sprouts in comparison with deep plowing (GA), has been determined in the fields that have been consistently levelled using harrow tines and flatcutting disc implements (KL). Area without straw (-Š) in comparison with deep ploughing (GA), substantially more barley seeds germinated in shallow ploughed (SA), shallow tine cultivator tines and flatcutting disc implements (KL) and the uncultivated stubble (ND) fields. Tenth day after the beginning of germination area with chopped or spread straw and area without straw in the background substantially less barley plants found in fields that have been consistently leveled harrow (RK). In the area with straw as well as in the area where sown in no-till stubble (ND) substantial differences were dicovered. Number of productive stems... [to full text]

Materiais lignocelulósicos, como a palha de cevada, são fontes de baixo custo com potenciais aplicações em bioprocessos. A fração hemicelulósica destes materiais pode ser hidrolisada usando-se ácidos minerais, para a liberação de seu principal açúcar componente, a xilose que é substrato para a bioprodução de xilitol. Já a fração celulósica pode ser deslignificada fazendo uso de álcalis e posteriormente hidrolisada com ácidos minerais para a liberação da glicose. O principal objetivo desta pesquisa foi avaliar economicamente a bioprodução de xilitol a partir da fração hemicelulósica da palha de cevada. A caracterização química da palha de cevada revelou a presença de 38,55% de celulose, 21,41% de hemicelulose e 19,90% de lignina. Após a etapa de caracterização a palha foi hidrolisada utilizando-se ácido sulfúrico para extração da xilose, empregando-se um planejamento fatorial 24-1. As melhores condições de hidrólise foram a uma temperatura de 120ºC, concentração ácida de 2,6%, tempo de reação de 20 minutos e relação sólido: líquido de 1:13,5. Nessas condições obteve-se um rendimento de extração de xilose da ordem de 84,38%. A celolignina resultante desse processo foi submetida a uma nova hidrólise de acordo com planejamento experimental 24-1 sendo que as melhores condições de hidrólise para a máxima eficiência de extração de glicose de 67,96% foi a uma temperatura de 179ºC, concentração ácida de 3%, tempo de reação de 30 minutos e relação sólido: líquido de 1:8. Após a realização das hidrólises, o hidrolisado hemicelulósico foi submetido à destoxificação para eliminação dos compostos inibitórios ao metabolismo microbiano e sua posterior fermentação com a levedura Candida guilliermondii enquanto o hidrolisado celulósico rico em glicose foi utilizado para suplementar o meio de fermentação constituído do hidrolisado hemicelulósico uma vez que a glicose foi um dos parâmetros nutricionais avaliados no planejamento fatorial 26-2 utilizado para as fermentações realizadas em frascos Erlenmeyer. Estes experimentos foram realizados por 72 horas e as melhores condições de cultivo determinadas pelo modelo foram: 3,0 g/L de sulfato de amônio, 1,0 g/L de cloreto de cálcio, 20,0 g/L de solução de extrato farelo de arroz e hidrolisado hemicelulósico contendo o teor de 60 g/L de xilose sendo que a concentração inicial de células em cada frasco foi de 1,0 g/L. Nestas condições obteve-se um consumo de xilose e eficiência de conversão de 96,59 e 59,98%, respectivamente, sendo a produtividade volumétrica de xilitol de 0,48 g/L.h. A fim de avaliar o efeito da disponibilidade de oxigênio sobre a bioconversão de xilose em xilitol foram realizadas fermentações empregando-se as melhores condições de cultivo obtidas em frascos agitados em reator de 1L onde os parâmetros agitação e aeração foram estudados segundo um planejamento fatorial 22. De acordo com os resultados os máximos valores de produção, produtividade volumétrica e fator de conversão de xilose em xilitol foram 51,28 g/L, 0,71 g/L.h e 0,88 g/g, respectivamente, quando a agitação foi de 200 rpm e aeração de 0,9 vvm (KLa≅18h-1) em 72 horas de fermentação. As condições de fermentação estabelecidas durante a utilização de reator de 1 L foram então empregadas para avaliar o processo a partir de um reator de maior capacidade (16 L), utilizando como critério de ampliação o KLa. Os valores de produção, produtividade volumétrica e fator de conversão de xilose em xilitol foram respectivamente 55,63 g/L, 0,77 g/L.h e 0,91 g/g, correspondendo a eficiência de conversão de 99,23%. O caldo fermentado resultante desta fermentação foi submetido à centrifugação e posterior clarificação. Por fim foi realizado um estudo econômico em cada etapa do processo considerando os equipamentos, os meios de cultivo empregados e reagentes, consumo de energia elétrica e água utilizados no processo, bem como a depreciação dos equipamentos. Após este estudo constatou-se que o valor para o xilitol produzido por via biotecnológica a partir do hidrolisado hemicelulósico de palha de cevada é de R$ 1.389,05.
Lignocellulosic materials, such as barley straw, are sources of low cost and with potential applications in bioprocesses. The hemicellulosic fraction of these materials can be hydrolyzed using mineral acids to release xylose, its major sugar component, which is substrate to bioproduction of xylitol. The cellulosic fraction can be delignified using alkalis followed by treatment with mineral acids to release glucose. The main objective of this research was to evaluate the economic bioproduction of xylitol from hemicellulosic fraction of barley straw. Chemical characterization of barley straw revealed the presence of 38.55% cellulose, 21.41% hemicellulose and 19.90% lignin. After the characterization stage, the barley straw was hydrolyzed with sulphuric acid for the extraction of xylose using a 24-1 factorial design. The optimum condition was temperature 120ºC, acid concentration 2.6%, reaction time 20 min and solid:liquid ratio 1:13.5. Under this condition the xylose extraction yield was about 84.38%. The celolignin was then submitted to a new hydrolyze according to a 24-1 factorial design and the best condition for maximum glucose extraction yield (67.96%) was temperature 179ºC, acid concentration 3%, reaction time 30 min and solid:liquid ratio 1:8. After hydrolysis, the hemicellulosic hydrolysate was submitted to a detoxification step to eliminate the compounds inhibitory to the microbial metabolism and fermentation with the yeast Candida guilliermondii while the cellulosic hydrolysate, rich in glucose, was used to supplement the fermentation medium consisting of the hemicellulosic hydrolysate as glucose was one of the nutritional parameters evaluated in the factorial design 26-2 employed to the fermentations carried out in Erlenmeyer flasks. These experiments were conducted for 72 h and the best culture conditions determined by the model were: 3.0 g/L ammonium sulfate, 1.0 g/L calcium chloride, 20.0 g/L solution of rice straw and hemicellulosic hydrolysate containing 60 g/L xylose. The initial cell concentration in each flask was 1.0 g/L. Under this condition the xylose consumption and conversion efficiency was 96.59 and 59.98%, respectively. The volumetric productivity of xylitol was 0.48 g/L.h. To evaluate the effect of oxygen availability on the bioconversion of xylose into xylitol It was realized fermentations employing the best culture conditions obtaining under agitation in 1L reaction where the parameters agitation and aeration were studied using a 22 factorial design. According to the results the maximum values of production, volumetric productivity and the factor of xylose concentration into xylitol were 51,28 g/L, 0.71 g/L.h and 0.88 g/g, respectively, when the agitation was 200 rpm and aeration 0.9 vvm (KLa≅18h-1) in 72 h fermentation. The fermentation conditions established during the utilization of 1 L reactor were then employed to evaluate the process from a reactor of higher capacity (16 L), and KLa was use as criteria to scale up. Production, volumetric productivity and the factor of xylose conversion into xylitol were 55.63 g/L, 0.77 g/L.h and 0.91 g/g, respectively, corresponding to a conversion efficiency of 99.23%. The fermented broth obtained from this fermentation was centrifuged and clarified. An economic study was realized for each stage of the process, considering equipment, reagents of the culture media, electric energy consumption and water utilized in the process, as well as equipment. It was found that the value of biotechnological produced xylitol from hemicellulosic hydrolysate of barley straw is R$ 1.389.05.

A large part of energy carriers and chemicals of our society come from fossil fuels; due to their critical exploitation and environmental concerns, alternative solutions should be promoted. The goal of this work is to understand the environmental impacts of different supply chains of levulinic acid production. To enable this comparison, a cradle-to-gate LCA was conducted on different kinds of biomasses, under an innovative thermochemical process called Biofine. The study concerns biomass not only of agri-food origin (corn stover, barley straw, wheat straw), but also deriving from the waste collection supply chain (organic fraction of municipal solid waste). Results show that biochemicals production from waste-derived biomass represent the lowest environmental impact solution, compared to the supply chain with biomass of agri-food origin. For agri-food biomasses, the impacts deriving from the agricultural phase are orders of magnitude more significant than those of the industrial phase, while the transport phase is the least impacting in absolute terms. For waste-derived biomasses, transport is the most impacting phase of the entire supply chain.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
In this dissertation, the materials corn straw and barley bagasse were investigated as alternative adsorbents for removal of the carbaryl pesticide from aqueous medium. For this, both materials were ground to obtain uniform particles (granulometry between 20 and 48 mesh) and treated with hydrated ethyl alcohol. The quantification of the carbaryl pesticide was made by High Efficiency Liquid Chromatography with UV-vis detector. The values of LD and LQ for the determination of the carbaryl pesticide by liquid chromatography using the method used were 0.01 mg L-1 and 0.10 mg L-1, respectively. The characterization of the adsorbent materials by FTIR showed the presence of the functional groups: hydroxyl, carbonyl and methyl, very common in lignocellulosic materials. The pH at the zero loading point (pHPCZ) was 7.08 for barley bagasse and 6.44 for corn straw. The adsorption capacity of the investigated materials was evaluated under different parameters such as material dose (g L-1), contact time between the pesticide solution and the adsorbent material (min) and the concentration of the pesticide in the solution (mg L-1). An alternative adsorption procedure was also proposed with the adsorbents packaged in a column where different doses of the adsorbents were evaluated and finally the adsorption process was evaluated using natural water samples. From the study of the dose of the materials the dose of 20 g L-1, equivalent to 200 mg of the adsorbent material in 10 mL of solution was selected, where 45.1% of the carbaryl was obtained when the barley bagasse was used and 49.2% when corn straw was used. For both adsorbents the kinetic study showed that the adsorption of the carbaryl agrochemical is best represented by the Avrami kinetic model, indicating that the adsorption of the carbaryl is not constant, but follows multiple orders. The maximum adsorption capacity (Qmax) was obtained by the construction of adsorption isotherms, where it was verified that the experimental data of the process of adsorption of the carbaryl by the barley bagasse is better represented by the Langmuir model providing a value of Qmax of 6, 5244 mg g-1. For corn straw, the Sips model was the most adequate with a Qmax value of 1.2625 mg g -1. In the column adsorption procedure the barley bagasse was efficient in all the doses evaluated, obtaining practically the same rate of removal as the procedure performed in batch mode, however in a much shorter time. As for the adsorbent corn straw, the removal through the column procedure was much less effective, suggesting that for this material the batch procedure is more adequate. In the adsorption study using natural water samples as an aqueous matrix, it was verified that the adsorption process of the carbaryl by both adsorbents can be affected by the pH of the medium and also by the presence of other compounds present in the aqueous matrix. In general, the results indicate that the barleybagasse and corn straw materials can be used as adsorbent materials in the treatment of aqueous medium contaminated with the carbaryl pesticide.
Nesta dissertação, os materiais palha de milho e bagaço de cevada foram investigados como adsorventes alternativos para remoção do agrotóxico carbaril de meio aquoso. Para isso, ambos materiais foram triturados para obtenção de partículas uniformes (granulometria entre 20 e 48 mesh) e tratados com álcool etílico hidratado. A quantificação do agrotóxico carbaril foi feita por Cromatografia Líquida de Alta Eficiência com detector UV-vis. Os valores de LD e LQ para a determinação do agrotóxico carbaril por cromatografia líquida, através do método empregado, foram 0,01 mg L-1 e 0,10 mg L-1, respectivamente. A caracterização dos materiais adsorventes por FTIR mostrou a presença dos grupos funcionais: hidroxila, carbonila e metila, bastante comuns em materiais lignocelulósicos. O pH no ponto de carga zero (pHPCZ) foi 7,08 para o bagaço de cevada e 6,44 para a palha de milho. A capacidade de adsorção dos materiais investigados foi avaliada sob diferentes parâmetros como dose do material (g L-1), tempo de contato entre a solução do agrotóxico e o material adsorvente (min) e a concentração do agrotóxico na solução (mg L-1). Foi proposto também um procedimento alternativo de adsorção com os adsorventes empacotados em uma coluna onde avaliou-se diferentes doses dos adsorventes e por fim avaliou-se o processo de adsorção utilizando amostras de água natural. A partir do estudo da dose dos materiais foi selecionada a dose de 20 g L-1, equivalente a 200 mg do material adsorvente em 10 mL de solução, onde foi obtida remoção de 45,1% do carbaril quando foi utilizado o bagaço de cevada e 49,2% quando foi usada a palha de milho. Para ambos os adsorventes o estudo cinético mostrou que a adsorção do agrotóxico carbaril é melhor representada pelo modelo cinético de Avrami, indicando que a adsorção do carbaril não é constante, mas segue múltiplas ordens. A capacidade máxima de adsorção (Qmáx) foi obtida pela construção de isotermas de adsorção, onde verificou-se que os dados experimentais do processo de adsorção do carbaril pelo bagaço de cevada é mais bem representado pelo modelo de Langmuir fornecendo um valor de Qmáx de 6,5244 mg g-1. Já para a palha de milho o modelo de Sips mostrou-se o mais adequado com um valor Qmáx de 1,2625 mg g-1. No procedimento de adsorção em coluna o bagaço de cevada mostrou-se eficiente em todas as doses avaliadas, obtendo praticamente a mesma taxa de remoção que o procedimento realizado em modo batelada, no entanto em um tempo bem menor. Já para o adsorvente palha de milho, a remoção através do procedimento em coluna foi bem menos efetiva, sugerindo que para este material o procedimento em batelada é mais adequado. No estudo de adsorção utilizando amostras de água natural como matriz aquosa, verificou-se que o processo de adsorção do carbaril por ambos os adsorventes pode ser afetado pelo pH do meio e também pela presença de outros compostos presentes na matriz aquosa. De um modo geral os resultados obtidos indicam que os materiais bagaço de cevada e palha de milho podem ser utilizados como materiais adsorventes no tratamento de meio aquoso contaminado com o agrotóxico carbaril.

Prymnesium parvum Carter, a haptophyte species capable of forming harmful algal blooms (HABs), has been identified in fresh and brackish water habitats worldwide. In Texas, P. parvum blooms have diminished local community revenues from losses to tourism, fishing, and hatchery production. In this thesis, P. parvum dynamics were studied using in-situ microcosm experiments at Lake Possum Kingdom, Texas during three seasons (fall, winter, spring) in 2004-2005. Specifically, nutrient additions were used to test the hypothesis that increased nutrient levels would not enhance P. parvum's ability to invade phytoplankton communities. In addition to full nutrient additions to levels of f/2 media, other treatments included nutrient additions deficient in either nitrogen (N) or phosphorus (P). Additionally, barley straw extract was tested as a growth inhibitor to prevent P. parvum blooms. Furthermore, P. parvum initial population density was examined to test the hypothesis that increased initial populations could promote an increase in P. parvum population densities. Findings indicated that P. parvum populations in Lake Possum Kingdom would not likely gain a selective advantage over other species when inorganic nutrients (nitrogen and phosphorus) were not limiting. P. parvum did, however, gain an advantage during both N- and P-limited conditions as indicated by toxicity, cell concentrations, and bulk phytoplankton community shifts. Furthermore, P. parvum blooms in Lake Possum Kingdom would likely not be inhibited by barley straw extract application. Initial population densities affected the final population density, but only when initial populations were low. A method to quickly and accurately detect the presence of P. parvum is needed due to P. parvum's potential to cause toxic and lethal blooms. This thesis tested whether P. parvum photopigments are conservative regardless of growth conditions and could be used to quantify the relative abundance of P. parvum in mixed community samples. If biomarker pigments are conservative, then an optimized version of CHEMTAX could be employed as an alternative diagnostic tool to microscopy for enumeration of P. parvum. However, P. parvum pigments in the Texas strain were not conservative throughout the growth cycle and therefore may not be a reliable indicator of cell abundance.

La demande mondiale croissante d’énergie et les préoccupations environnementales croissantes ont propulsé l’exploration d’alternatives durables aux sources de carburant conventionnelles. La biomasse se présente comme une ressource renouvelable prometteuse, capable d'atténuer la crise énergétique mondiale tout en garantissant la durabilité environnementale. Cette étude se penche sur le comportement de combustion de trois biomasses distinctes : le bois d'origine forestière, le miscanthus herbacé et la paille d'orge résiduelle agricole. En examinant le comportement des particules individuelles pendant la combustion, la recherche cherche à élucider les processus fondamentaux régissant la conversion de la biomasse en énergie et à comprendre les comportements de combustion uniques des différentes sources de biomasse. La complexité de la combustion de la biomasse, influencée par des facteurs tels que la composition chimique, la teneur en éléments et les étapes de combustion, est au cœur de l'enquête. Les premiers résultats mettent en évidence les effets catalytiques potentiels d’éléments mineurs comme le sodium (Na) et le potassium (K) sur le comportement de combustion, ce qui nécessite des études approfondies pour comprendre pleinement leur influence. Grâce à une caractérisation complète, l'étude identifie trois étapes critiques de combustion des particules de biomasse : la perte d'humidité, la dévolatilisation et l'oxydation du charbon, révélant des distinctions significatives dans les points d'inflammation entre les sources de biomasse étudiées. La thèse vise à contribuer de manière significative à la compréhension de la production d'énergie basée sur la biomasse et de ses implications environnementales, en fournissant une base pour les progrès futurs dans l'utilisation de la biomasse, la production d'énergie et les pratiques durables
The escalating global demand for energy and mounting environmental concerns have propelled the exploration of sustainable alternatives to conventional fuel sources. Biomass stands out as a promising renewable resource capable of alleviating the worldwide energy crisis while addressing environmental sustainability. This study delves into the combustion behavior of three distinct biomass: forest-derived wood, herbaceous miscanthus, and agricultural residue barley straw. By scrutinizing individual particle behavior during combustion, the research seeks to unravel the fundamental processes governing biomass conversion into energy and understand the unique combustion behaviors of different biomass sources. The complexity of biomass combustion, influenced by factors like chemical composition, elemental content, and combustion stages, lies at the heart of the investigation. Initial findings highlight potential catalytic effects of minor elements like sodium (Na) and potassium (K) on combustion behavior, prompting the need for in-depth studies to fully comprehend their influence. Through comprehensive characterization, the study identifies three critical combustion stages for biomass particles: humidity loss, devolatilization, and char oxidation, revealing significant distinctions in ignition points among the investigated biomass sources. The thesis aims to significantly contribute to understanding biomass-based energy generation and its environmental implications, providing a foundation for future advancements in biomass utilization, energy production, and sustainable practices

The objectives of this study were to verify the potential benefits of growing green barley on anaerobic enzyme (ZAD) treated rice straw. In addition, the work intended to investigate the effect of this treatment on digestibility parameters in Ossimi sheep. A complete random design was used to distribute twelve mature male of Ossimi sheep (45.0 +0.5 Kg wt.) on the following treatments: Rice straw with grown barley (RSGB) without either ZAD or orange pulp (control, T1), RSGB plus ZAD (T2), RSGB plus orange pulp (T3) and RSGB + ZAD + orange pulp (T4). The obtained results could be summarized as follow 1- Significant decreases were observed in %CF from 38.09 for T1 to 32.01 and 30.02 for rations T4 and T2 respectively (P< 0.05). Percentage values of NDF were 70.01, 72.10 and 76.01 for rations T4, T2 and T1 respectively (P< 0.05); while %ADF values were 50.05, 52.10 and 58.10 for rations T4, T2 and T1 respectively (P< 0.05) and %ADL was 6.01for T4 versus 8.01for T1. And significant increases in %CP content to 7.96, 7.10, 7.95 for ration T4, T3, T2 respectively compared to the control ration was 5.75 (P< 0.05). 2- Adding ZAD to RSGB significantly increased (p< 0.05) %TDN to 55.02 and 59.02 for treatments T2 and T4 respectively and increased digestibility coefficients of CP to 72.43 and 77.70 respectively. 3- Rams fed rations T2, T3 and T4 had significantly higher values of ruminal ammonia-N 3 hrs. post feeding values were 25.41, 25.03, 25.96 mg/100ml respectively and total volatile fatty acids 3 hrs. post feeding were 8.20, 8.13 and 8.26 m.eq/100ml respectively. 4- Adding either ZAD, orange pulp or both to RSGB significantly increased (p<.05) plasma total protein values were 6.43, 6.23, 5.82 g/dl for treatments T4, T3, T2 respectively , while treating rations with ZAD reflected low level of GPT 6 hrs. post feeding values were 20.64 and 20.61 for treatments T2 and T4 respectively versus T1 (20.90 µ/l). It could be concluded that anaerobic enzyme matrix (ZAD) improved the nutritive value of soilless green barley and improved their digestibility coefficients in Ossimi sheep ZAD is a compound of enzymes are separated from anaerobic bacteria separated from the rumen, it contain a mixture of cellulase, hemicellulase, protease and alpha amylase enzymes.

The energy requirements of the world has accelerated search for new fuels or new sources of fuel. Ethanol or butanol production from lignocellulosic biomass is one example of this. As lignin constrains the access of cellulose or hemicellulose to enzymes for their hydrolysis, it is necessary to remove the lignin. Various pretreatment methods are used before going for the hydrolysis of cellulose present in biomass followed by hydrolysis. In this work, barley straw is chosen as the lignocellulosic biomass and production of butanol has been carried out using steam explosion and acid hydrolysis followed by fermentation. The maximum amount of sugar (37.51 mg/ml of hydrozylate solution) was produced after the hydrolysis by HNO3 with 0.5 mol/ltr concentration. The maximum amount of butanol (3.046mg/ml) was also found by hydrolyzing with 0.5 mol/ltr of HNO3 after the fermentation of hydrozylate

Lignocellulosic biomass is composed of cellulose, hemicellulose, lignin and extraneous compounds (waxes, fats, gums, starches, alkaloids, resins, tannins, essential oils, silica, carbonates, oxalates, etc). The sugars within the complex carbohydrates (cellulose and hemicellulose) can be accessed for cellulosic bioethanol production through ethanologenic microorganisms. However, the composite nature of lignocellulosic biomass, particularly the lignin portion, presents resistance and recalcitrance to biological and chemical degradation during enzymatic hydrolysis/saccharification and the subsequent fermentation process. This leads to a very low conversion rate, which makes the process uneconomically feasible. Thus, biomass structure requires initial breakdown of the lignocellulosic matrix. In this study, two types of biomass pretreatment were applied on barley straw grind: radio-frequency (RF)-based dielectric heating technique using alkaline (NaOH) solution as a catalyst and steam explosion pretreatment at low severity factor. The pretreatment was applied on barley straw which was ground in hammer mill with a screen size of 1.6 mm, so as to enhance its accessibility and digestibility by enzymatic reaction during hydrolysis. Three levels of temperature (70, 80, and 90oC), five levels of ratio of biomass to 1% NaOH solution (1:4, 1:5, 1:6, 1:7, & 1:8), 1 h soaking time, and 20 min residence time were used for the radio frequency pretreatment. The following process and material variables were used for the steam explosion pretreatment: temperature (140-180oC), retention time (5-10 min), and 8-50% moisture content (w.b). The effect of both pretreatments was assessed through chemical composition analysis and densification of the pretreated and non-pretreated biomass samples. Results of this investigation show that lignocellulosic biomass absorbed more NaOH than water, because of the hydrophobic nature of lignin, which acts as an external crosslink binder on the biomass matrix and shields the hydrophilic structural carbohydrates (cellulose and hemicellulose). It was observed in the RF pretreatment that the use of NaOH solution and the ratio of biomass to NaOH solution played a major role, while temperature played a lesser role in the breakdown of the lignified matrix, as well as in the production of pellets with good physical quality. The heat provided by the RF is required to assist the alkaline solution in the deconstruction and disaggregation of lignocellulosic biomass matrix. The disruption and deconstruction of the lignified matrix is also associated with the dipole interaction, flip flop rotation, and friction generated between the electromagnetic charges from the RF and the ions and molecules from the NaOH solution and the biomass. The preserved cellulose from the raw sample (non-treated) was higher than that from the RF alkaline pretreated samples because of the initial degradation of the sugars during the pretreatment process. The same observation applies to hemicellulose. This implies that there is a trade-off between the breakdown of the biomass matrix/creating pores in the lignin and enhancing the accessibility and digestibility of the cellulose and hemicellulose. The use of dilute NaOH solution in biomass pretreatment showed that the higher the NaOH concentration, the lower was the acid insoluble lignin and the higher was the solubilized lignin moieties. The ratio of 1:6 at the four temperatures studied was determined to be the optimal. Based on the obtained data, it is predicted that this pretreatment will decrease the required amount and cost of enzymes by up to 64% compared to using non-treated biomass. However, the use of NaOH led to an increase in the ash content of biomass. The ash content increased with the decreasing ratio of biomass to NaOH solution. This problem of increased ash content can be addressed by washing the pretreated samples. RF assisted-alkaline pretreatment technique represents an easy to set-up and potentially affordable route for the bio-fuel industry, but this requires further energy analysis and economic validation, so as to investigate the significant high energy consumption during the RF-assisted alkaline pretreatment heating process. Data showed that in the steam explosion (SE) pretreatment, considerable thermal degradation of the energy potentials (cellulose and hemicellulose) with increasing acid soluble and insoluble lignin content occurred. The high degradation of the hemicellulose can be accounted for by its amorphous nature which is easily disrupted by external influences unlike the well-arranged crystalline cellulose. It is predicted that this pretreatment will decrease the required amount and cost of enzymes by up to 33% compared to using non-treated biomass.The carbon content of the solid SE product increased at higher temperature and longer residence time, while the hydrogen and oxygen content decreased. The RF alkaline and SE treatment combinations that resulted to optimum yield of cellulose and hemicellulose were selected and then enzymatically digested with a combined mixture of cellulase and β-glucosidase enzymes at 50oC for 96 h on a shaking incubator at 250 rev/min. The glucose in the hydrolyzed samples was subsequently quantified. The results obtained confirmed the effectiveness of the pretreatment processes. The average available percentage glucose yield that was released during the enzymatic hydrolysis for bioethanol production ranged from 78-96% for RF-alkaline pretreated and 30-50% for the SE pretreated barley straw depending on the treatment combination. While the non-treated sample has available average percentage glucose yield of just below 12%. The effects of both pretreatment methods (RF and SE) were further evaluated by pelletizing the pretreated and non-pretreated barley straw samples in a single pelleting unit. The physical characteristics (pellet density, tensile strength, durability rating, and dimensional stability) of the pellets were determined. The lower was the biomass:NaOH solution ratio, the better was the quality of the produced pellets. Washing of the RF-alkaline pretreated samples resulted in pellets with low quality. A biomass:NaOH solution ratio of 1:8 at the three levels of temperature (70, 80, and 90oC) studied are the RF optimum pretreatment conditions. The higher heating value (HHV) and the physical characteristics of the produced pellets increased with increasing temperature and residence time. The steam exploded samples pretreated at higher temperatures (180ºC) and retention time of 10 min resulted into pellets with good physical qualities. Fourier transform infrared-photoacoustic spectroscopy (FTIR-PAS) was further applied on the RF alkaline and SE samples in light of the need for rapid and easy quantification of biomass chemical components (cellulose, hemicellulose, and lignin). The results obtained show that the FTIR-PAS spectra can be rapidly used for the analysis and identification of the chemical composition of biofuel feedstock. Predictive models were developed for each of the biomass components in estimating their respective percentage chemical compositions.

Little is known about the effect of the influence of water availability, crop residue quality and plant growth on phosphorus (P) pools in the detritusphere, the soil adjacent to plant residues. The detritusphere soil was generated in microcosms as described in Ha et al. (2007). The soil at 0-2 mm distance from the surface of soil incubated in PVC caps was collected as the detritusphere soil and used for further experiments. Bioavailable P pools (readily available P pools: CaCl2 and anion exchange P; P bound to soil particles: citrate and HCl P; acid phosphatase and microbial P), available N and microbial N were measured in the detritusphere. The experiment described in Chapter 2 investigated the influence of drying and rewetting on soil P pools in the detritusphere of two crop residues, young faba bean residue (C/P 38) and mature barley straw (C/P 255). The detritusphere and unamended control soils were dried to approximately 5% water holding capacity (WHC) and kept dry for two weeks followed by rapid rewetting to 50% WHC, or maintained at 50% of WHC. Rewetting of dry soils induced a respiration flush and the flush was greater with faba bean than barley. P pools were higher with faba bean than with barley, due to lower C/P ratio of the former. In general, drying and rewetting had little effect on P pools. In Chapter 3, an experiment is described that assessed the influence of soil water availability on P pools in the detritusphere of crop residues. Detritusphere was generated with barley straw (C/P 255) or barley straw mixed with faba bean residue at a 75:25 ratio (C/P 200) in soil at 50% WHC. Water availability in the detritusphere soils was reduced to -0.320 and -1.700 MPa (30% and 10% WHC), or maintained at -0.078 MPa (50% WHC). In the detritusphere of the residue mix, soil respiration, P pools and available N were lower at -1.700 MPa than at -0.078 MPa. However, water availability had little effect in barley detritusphere. The aim of the experiment described in Chapter 4 was to elucidate the effect of soil amendment with inorganic N and P on P pools in the detritusphere of mature barley straw (C/N 95; C/P 255). Addition of inorganic N to soil increased P pools likely due to enhanced mineralisation of native soil organic matter. Barley straw decomposition reduced available P pools in the detritusphere, particularly in soil to which inorganic P was added. In Chapter 5, an experiment was described to determine the influence of a change of residue types on P pools in the detritusphere of crop residues with differing C/P ratios. In the first experiment, after two weeks of incubation at 50% WHC, with young faba bean residue (L) or mature barley straw (H), the residues were replaced with either a H or L, resulting in four residue treatments: high-high (HH), high-low (HL), low-low (LL) or low-high (LH), which were incubated for another 14 days. On day 14, P pools and available N were higher, but MBP and MBN were lower in L than in H. On day 28, P pools and available N followed the order LL>HL>LH>HH, whereas MBN and MBP were highest in HL. The experiment described in Chapter 6 aimed to determine the influence of residue C/P ratio on changes in P pools and N availability in wheat rhizosphere. Pre-germinated wheat seeds were sown in unamended soil or soil amended with two crop residues (young faba bean residue, C/P 38; mature barley straw, C/P 255). After 28 days with faba bean, P uptake in wheat was higher than with barley straw and control. P pools were lower in the interface of wheat rhizosphere and faba bean detritusphere than in detritusphere alone, due to plant uptake. With barley straw, presence of wheat roots had no effect on P pools.
Thesis (Ph.D.) -- University of Adelaide, School of Agriculture, Food & Wine, 2019