Dissertations / Theses on the topic 'Digestion of lignocellulosic biomass'
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Liew, Lo Niee. "Solid-state Anaerobic Digestion of Lignocellulosic Biomass for Biogas Production." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1306870552.
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Lin, Long. "Technical, Microbial, and Economic Study on Thermophilic Solid-state Anaerobic Digestion of Lignocellulosic Biomass." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1500505570855855.
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Brown, Dan Lee. "Comparison of Solid-State to Liquid Phase Anaerobic Digestion of Lignocellulosic Biomass for Biogas Production." The Ohio State University, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=osu1341870854.
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Xu, Fuqing. "Experimental Studies and Modeling of Solid-State Anaerobic Digestion for Enhanced Methane Production from Lignocellulosic Biomass." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1406143408.
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Kumi, Philemon James. "Improving the bioconversion of lignocellulosic feedstock to bio-fuels and chemicals." Thesis, University of South Wales, 2015. https://pure.southwales.ac.uk/en/studentthesis/improving-the-bioconversion-of-lignocellulosic-feedstock-to-biofuels-and-chemicals(7088d092-fb93-4d70-ba3d-1abb233e33e3).html.
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This study investigated the fate of lignocellulosic biomass (wheat-feed and perennial rye grass) in different anaerobic digestion systems, evaluating the role of substrate specificity on the pattern of degradation. The two-stage (biohydrogen-biomethane) anaerobic system was found to be more effective in the degradation of lignocellulose, when compared to the conventional single-stage system. The perennial rye grass substrate possessed about 21% higher holocellulose concentration when compared to the wheat-feed; its exploitation in the acidogenic digestion was however poor, resulting in a 2.9% lower biogas yield in a equivalent two-stage system. The study therefore developed a treatment technique involving the use of cellulase and ferulic acid esterase enzyme combinations for the treatment of perennial rye grass. The enzyme cocktail at 0.202 ml enzyme/g VS added resulted in efficient bioconversion of the complex polymers to soluble carbohydrates, evident in the yield increase of soluble COD, to 321.0±10.9 mg/gVS, a 393.2% yield increase, when compared to the no enzyme added control. The yield of bio-hydrogen after enzymatic addition was 48ml/gVS, 335% higher when compared to the alkaline treatment; and more than seven fold higher than the yield obtained from the fermentation with no pre-treatment. The acetate to butyrate ratio varied from 4:1, when no pre-treatment was used, to 2:1when alkaline pre-treatment was used, then to 1:1 after the enzymatic treatment. The downstream effect of the prior hydrolysis on the subsequent processes to acidogenic fermentation like biomethane and PHA production and lignin recovery were also investigated. The hydrogenic/acidogenic fermentation resulted in methane yield improvement of 45.7%. The study shows that the more effective a hydrolysis procedure is in the depolymerisation of complex polymers, the greater the accumulation of PHA in the PHA biosynthesis operations. The enhanced hydrogenic /acidogenic fermentation having effectively degraded the holocellulose component of the perennial rye grass substrate ensured that relatively high quality lignin was obtained in an Organosolv lignin-extraction procedure. FT-IR profile show less contamination of polysaccharides and proteins in the lignin extracted from the enzymatically enhanced acidogenic fermentation. An evaluation of the economic viability of the investigated secondary processes showed that direct integrations of those processes to the biohydrogen process may not be as economically advantageous, when compared to a 2nd -stage biomethanation system.
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Mancini, Gabriele. "Different approaches to enhance the biogas production from the anaerobic digestion of lignocellulosic materials." Thesis, Paris Est, 2017. http://www.theses.fr/2017PESC1250/document.
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La production de biogaz par digestion anaérobie (DA) est une technologie renouvelable de longue date et un bioprocessus en croissance continue. Les matériaux lignocellulosiques (ML) présentent plusieurs caractéristiques qui les rendent particulièrement attrayants parmi les substrats couramment employés dans les bioréacteurs anaérobies. En particulier, les ML sous la forme de résidus agricoles ont été reconnus comme la matière première la plus appropriée pour la production de biométhane en raison de leur haute disponibilité, de leur faible coût, de leur durabilité et de leur absence de concurrence directe avec la production alimentaire. Cependant, leur récurrence à la conversion biologique entrave leur application pour la production à grande échelle de biogaz et nécessite une étape de prétraitement pour améliorer la dégradabilité microbienne. En plus des défis posés par la structure lignocellulosique, la fourniture de oligo-éléments (OE) a souvent été jugée insuffisante dans les digesteurs de biogaz. La croissance microbienne dépend de la disponibilité et de la quantité optimale de plusieurs OE spécifiques, constituants essentiels des cofacteurs dans les systèmes enzymatiques impliqués dans la biochimie de la formation de méthane. Différents prétraitements chimiques, à savoir le N-méthylmorpholine-N-oxyde (NMMO), le procédé organosolv et un prétraitement alcalin à l'aide de NaOH ont été étudiés pendant plusieurs expériences en lots pour améliorer les rendements de production de biogaz différents peau, coquille de fève de cacao et paille de blé). Les changements dans la cristallinité de la cellulose, la valeur de rétention d'eau et la composition chimique ont été évalués pour mieux évaluer l'effet des différents prétraitements étudiés sur la structure lignocellulosique. En outre, l'addition de différentes doses de Fe, Co, Ni et Se sur la DA de paille de riz a été étudiée, évaluant l'influence de l'origine de l'inoculum, ainsi que la performance et l'effet synergique de la combinaison d'un prétraitement alcalin avec addition de trace éléments avant la DA de paille de riz. La biodisponibilité des OE lors des tests de potentiel de biométhane par lots a également été évaluée en appliquant une technique d'extraction séquentielle. Les trois prétraitements étudiés étaient des méthodes efficaces pour améliorer la production de biométhane à partir des LM utilisées. Le rendement en biométhane de la DA de paille de riz a augmenté de 82 et 41% respectivement après le NMMO et le prétraitement organosolv. Comparé à la même expérience, le prétraitement NMMO, organosolv et NaOH a permis d'améliorer la DA de la paille de blé, ce qui affecte différemment la composition chimique de la LM brute. Le rendement cumulatif de production de biométhane de 274 mL de CH4/g VS obtenu avec la paille de blé non traitée a été augmenté de 11% par le prétraitement du NMMO et de 15% par le prétraitement organosolv et alcalin. Les coquilles de noisettes et de fèves de cacao, qui n'avaient jamais été étudiées auparavant comme substrats AD, présentaient un bon potentiel de production de biogaz, avec des rendements cumulatifs de biométhane respectivement de 223-261 et 199-231 mL CH4/g VS pour les charges non traitées. Cependant, les prétraitements à la fois de NMMO et d'organosolv n'ont pas conduit à une amélioration significative des rendements de production de biométhane de ces deux LM. La supplémentation des OE n'a eu qu'un effet mineur par rapport aux méthodes de prétraitement. L'ajout de Fe, Co, Ni et Se n'a pas entraîné d'amélioration significative de la DA de paille de riz, alors que l'utilisation du prétraitement de NaOH au cours de la même expérimentation a provoqué une augmentation considérable de la DA, augmentant la production de biogaz de 21%. L'effet négligeable observé après la supplémentation des OE sur la paille de riz pourrait être lié à sa structure lignocellulosique complexe qui nécessite une amélioration de l'hydrolyse qui est l'étape limitanteBiogas production via anaerobic digestion (AD) is a long-standing renewable technology and a continuously growing bioprocess worldwide. Lignocellulosic materials (LMs) present several features that make them especially attractive among the organic substrates commonly employed in anaerobic bioreactors. In particular, LMs under the form of agricultural residues have been acknowledged as the most suitable feedstock for biomethane production due to their high availability, low cost, sustainability and no direct competition with food and feed production. However, their recalcitrance to biological conversion hinders their application for full-scale production of biogas and requires a pretreatment step to improve the LM microbial degradability. In addition to the challenges posed by the lignocellulosic structure, the supply of trace elements (TEs) has often been found insufficient within biogas digesters. The microbial growth depends on the availability and optimal amount of several specific TEs, which are essential constituents of cofactors in enzyme systems involved in the biochemistry of methane formation. Different chemical pretreatments, namely the solvent N-methylmorpholine-N-oxide (NMMO), the organosolv process, and an alkaline pretreatment using NaOH, were investigated during several batch experiments to enhance the biogas production yields from different LMs (i.e. rice straw, hazelnut skin, cocoa bean shell and wheat straw). Changes in the cellulose crystallinity, water retention value and chemical composition were assessed to better evaluate the effect of the different pretreatments studied on the lignocellulosic structure. Furthermore, the addition of different doses of Fe, Co, Ni and Se on the AD of rice straw was studied, evaluating the influence of the inoculum origin, as well as the performance and synergistic effect of combining an alkaline pretreatment with the addition of trace elements prior to the AD of rice straw. The bioavailability of TEs during batch biomethane potential tests was also evaluated applying a sequential extraction technique. The three pretreatments investigated were effective methods for enhancing the biomethane production from the employed LMs. The biomethane yield from the AD of rice straw increased by 82 and 41% after the NMMO and organosolv pretreatment, respectively. When compared within the same experiment, the NMMO, organosolv and NaOH pretreatment were able to improve the AD of wheat straw, differently affecting the chemical composition of the raw LM. The cumulative biomethane production yield of 274 mL CH4/g VS obtained with the untreated wheat straw was enhanced by 11% by the NMMO pretreatment and by 15% by both the organosolv and alkaline pretreatment. Hazelnut skin and cocoa bean shell, which were never investigated before as AD substrates, showed a good potential for biogas production, with cumulative biomethane yields of 223-261 and 199-231 mL CH4/g VS, respectively, for the untreated feedstocks. However, both NMMO and organosolv pretreatments did not lead to a significant enhancement of the biomethane production yields from these two LMs. The TE supplementation had only a minor effect compared to the pretreatment methods. The addition of Fe, Co, Ni and Se did not result in a significant improvement of the AD of rice straw, whereas the use of the NaOH pretreatment, during the same batch experiment, caused a considerable enhancement of the AD, increasing the biogas production yield by 21%. The negligible effect observed after TE supplementation on the AD of rice straw could be linked to its complex lignocellulosic structure, which requires an enhancement of the hydrolysis, which, rather than the methanogenesis, is the rate-limiting step
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Thomas, Hélène. "Etude de l'impact des pré-traitements alcalins sur la digestion anaérobie du sorgho et du miscanthus." Electronic Thesis or Diss., Montpellier, SupAgro, 2019. http://www.theses.fr/2019NSAM0011.
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Dans le contexte du réchauffement climatique et de la diminution des réserves de combustibles fossiles, la biomasse lignocellulosique peut fournir une source renouvelable d'énergie, de matériaux et de produits chimiques. En particulier, la production de biogaz par méthanisation est en plein essor. C’est dans ce contexte de bioraffinerie environnementale que se situe ce projet de thèse. Il porte sur deux biomasses lignocellulosiques différentes : le sorgho et le miscanthus ayant l'avantage de combiner un fort potentiel de production de biomasse avec un impact minimal sur l'environnement. Pour ce type de biomasse, il est bien connu que la lignine joue un rôle de barrière à l’accessibilité des composés. Cette thèse a pour objectif de d’étudier l’impact des pré-traitements alcalins, connus pour délignifier la biomasse de manière efficace et ainsi améliorer son bioaccessibilité et donc sa dégradation par digestion anaérobie. L’étude de l’impact de ces pré-traitements sur la composition biochimique des biomasses et leur production méthane a montré que ces impacts diffèrent en fonction de la biomasse et des conditions opératoires des pré-traitements appliqués (réactif, durée, température, teneur en eau). Dans un objectif d’application de co-digestion en méthanisation agricole, l’impact de certains des prétraitements de ces deux biomasses a été étudié lors d’essais en réacteurs batch à recirculation. Le sorgho s’est révélé être un co-substrat adéquat du fumier. Enfin, l’étude originale des mécanismes d’action de ces pré-traitements à l’échelle de la structure anatomique de la biomasse a montré que les pré-traitements agissent différemment suivant la localisation et le type de lignine. Ces travaux de thèse permettent donc une meilleure compréhension de l’impact des pré-traitements sur différentes biomasses lignocellulosiquesIn the context of global warming and declining fossil fuel reserves, lignocellulosic biomass can provide a renewable source of energy, materials and chemicals. In particular, biogas production by anaerobic digestion is facing a fast development. This thesis project takes place in this biorefinery concept. Two different lignocellulosic biomasses, which present the advantage of combining high biomass production potential with minimal environmental impact, were studied. For this kind of biomass, it is well known that lignin acts as a barrier to the accessibility of compounds. The objective of this thesis was to study the impact of alkaline pre-treatments, known be efficient in biomass delignification and thus improve its bioaccessibility and its degradation by anaerobic digestion. The study of the impact of these pre-treatments on the biochemical composition of biomasses and their methane production showed that these impacts were different according the biomass and the operating conditions of the applied pre-treatments (reagent, duration, temperature, water content). With the aim of applying it in agricultural anaerobic co-digestion context, the impact of some of these pre-treatments of sorghum and miscanthus was studied in leach bed reactors. Sorghum was found to be an adequate co-substrate for manure. Finally, the original study of the mechanisms of action of these pre-treatments at the biomass anatomical structure scale showed that the pre-treatments act differently depending on the location and type of lignin. This thesis work therefore allows a better understanding of the impact of pre-treatments on different lignocellulosic biomasses
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Silva, Vanessa Cristina da. "Obtenção anaeróbia de etanol em reator em batelada a partir de glicose, xilose e celulose em condição termófila." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/18/18138/tde-14082015-142835/.
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A biomassa lignocelulósica é uma alternativa atrativa para o aumento na oferta de biocombustíveis, uma vez que é constituída de celulose e hemicelulose. Esses polímeros são constituídos principalmente de unidades menores de glicose e xilose, os quais por meio de bactérias anaeróbias termófilas, podem ser metabolizados em etanol. Portanto, estabeleceu-se o objetivo desse trabalho, em utilizar as principais fontes de carbono da biomassa lignocelulósica (celulose, glicose e xilose), e produzir etanol por meio da ação de consórcio microbiano selecionado a partir de inóculo termófilo e anaeróbio. O inóculo foi submetido a condição de crescimento com variação de pH (2,3,4,5,6,e 7) e variação de dois meios de cultivo em reatores em batelada, visando favorecer bactérias celulolíticas e fermentativas produtoras de etanol. Para a produção de etanol, o pH e meio de cultivo mais adequados foram 7,0 e Meio Thermoanaerobacter ethanolicus, respectivamente. A partir do inóculo enriquecido nas condições nutricionais de pH e meio de cultivo, prosseguiu-se a realização dos ensaios de produção de etanol a partir de celulose, glicose e xilose (1g/L de cada substrato), em pH 7 e meio T. ethanolicus. Os ensaios foram realizados em reator em batelada, em triplicata, a 55 ºC, ambos seguidos de um reator controle, sem adição desses substratos orgânicos. Os rendimentos de etanol foram de 1,73 mol etanol/mol glicose e 1,33 mol de etanol /mol de xilose. Para o substrato celulose obteve-se 1,88 mmol de etanol/g de celulose. Para os reatores controle de glicose, celulose e xilose, no qual o extrato de levedura foi a única fonte orgânica adicionada, a produção de etanol foi 1,27 mmol/L, 0,39 mmol/L e 1,65 mmol/L, respectivamente. Em todos os reatores foi detectado produção de ácido acético, ácido butírico e ácido propiônico. A produção de ácido acético foi de 5,73 mmol/L, 9,73 mmol/L e 14,45 mmol/L, para os reatores de glicose, celulose e xilose, respectivamente. No reator com glicose, observou-se baixo rendimento de hidrogênio (0,31 mol hidrogênio/mol glicose), e nos demais reatores não foi constatado produção desse gás. Em contrapartida, observou-se rendimentos de 6,6 mmol de metano/g de celulose e 0,68 mol de metano/mol de xilose para os respectivos reatores. Dessa forma, pode-se mencionar que em função das características do consórcio microbiano foi possível obter a degradação da celulose e metabolização da glicose e xilose em etanol.Lignocellulosic biomass is an attractive alternative to increase biofuels proposal, as its composed of cellulose and hemicellulose. These polymers are consisted in individual molecules of glucose and xylose, through some thermophilic bacteria, can metabolize these carbohydrates in ethanol. Therefore, this study reports on using the principals carbon sources of lignocellulosic biomass (cellulose, glucose, and xylose), and producing ethanol through microbial consortium from anaerobic and thermophilic inoculum. The biomass was submitted to variation of pH (2,3,4,5,6, and 7) and two kinds of medium, due to ethanol production in batch reactors. For ethanol production, the optimized pH and medium were 7,0 and Thermoanaerobacter ethanolicus medium, respectively. The enriched culture was being cultivated in pH and medium experiments were used to ethanol production experiments that carried out in batch reactors, from cellulose, glucose and xylose were realized in triplicate and were maintained at 55 °C, in both batches had a control reactor (without these organics substrates). Positive results in ethanol yields were 1,73 mol ethanol/ mol glucose and 1,33 mol ethanol/ mol xylose. In celluloses reactors the microbial consortium was efficient in substrate degradation, however, was obtained lower ethanol yields (1,88 mol ethanol/ g cellulose). In control reactors from glucose, cellulose and xylose, that yeast extract was the unique organic source, ethanol production was 1,27 mmol/L, 0,39 mmol/L e 1,65 mmol/L, respectively. In all reactors were detected acetic, butyric and propionic acids. The acetic acid production was 5,73 mmol/L, 9,73 mmol/L e 14,45 mmol/L in glucose, cellulose and xylose reactors, respectively. For glucoses reactors were observed lower hydrogen production (0,31 mol hydrogen/ mol glucose), in the other reactors did not observed gases production. Instead of the following yields were obtained: 6,6 mmol methane/ g cellulose and 0,68 mol methane/ mol xylose. Taking this into account, microbial consortium enriched had characteristics to degrade cellulose and metabolize glucose and xylose to ethanol.
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Pinilla, Maria Juliana. "Comparative Life Cycle Assessments of Lignocellulosic and Algae Biomass Conversion to Various Energy Products through Different Pathways." Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3740.
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Bioenergy has the potential to reduce the world's dependence on fossil fuels, and to decrease the CO2 emissions due to fossil combustion. Lignocellulosic and algae biomass have been presented as promising feedstocks for bioenergy production.
In this study, a comparative Life Cycle Assessment (LCA) has been developed to evaluate the environmental impacts associated with different energy products via different routes across the whole life of algal and lignocellulosic bioenergy. Results were compared per energy basis, the production of 1 million BTU of energy products.
For the development of the comparative algae biomass conversion LCA, algal biomass was converted to liquid biofuels via a thermochemical gasification and Fisher-Tropsch Synthesis (FTS) process; and to electricity and heat via anaerobic digestion and combined heat and power (CHP) process. Overall results from the algae biomass conversion LCA showed that the process that converts algae biomass through anaerobic digestion and CHP process to electricity and heat had the highest overall environmental impact. Results also showed that the impact categories that appear to contribute the most to the overall impacts are ecotoxicity, human health non-cancer, and human health cancer.
For the development of the comparative lignocellulosic biomass conversion LCA, lignocellulosic biomass was converted to ethanol and higher alcohols through thermochemical gasification and alcohol synthesis process, to liquid biofuels via thermochemical gasification and FTS process, and to liquid biofuels via a thermochemical gasification and FTS process that uses methane. Overall results from the lignocellulosic biomass conversion LCA showed that the process that converts lignocellulosic biomass into alcohols has the highest overall environmental impact. Results also showed that the impact categories that appear to contribute the most to the overall impacts are ecotoxicity, human health non-cancer, human health cancer, and global warming.
This study determined that cultivated algae biomass feedstock has much higher environmental impacts compared with lignocellulosic biomass feedstock from forestation and agriculture byproducts. It was also concluded that thermochemical gasification and FTS process showed higher efficiency when converting biomass to bioenergy.
In addition, the five biomass to bioenergy conversion pathways used in the development of this LCA study were compared. Results showed that the pathway with lignocellulosic biomass (feedstock), thermochemical gasification and alcohol synthesis process (conversion process), and ethanol and higher alcohols (energy products) has the largest environmental impact.
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Puthumana, Amal Babu. "Effect of feed ratio and pre-treatment on methane yields during anaerobic co-digestion of sugarcane bagasse and trash with chicken manure." Thesis, Griffith University, 2020. http://hdl.handle.net/10072/393971.
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Australia is one of the major producers and exporter of agricultural products. Annually, Australian agriculture produces approximately 151 Tg CO2 equivalent emissions. The use of fossil fuels in crop cultivation, harvesting and transportation are considered as the primary source of these greenhouse gas (GHG) emissions. Moreover, agronomic management and crop residues left in the field also contribute to these GHG emissions. Alternative waste management practices include the use of crop residues and agro-wastes as feedstocks for bioenergy production. Anaerobic digestion is considered as sustainable environmental technology to convert industrial sugarcane residues to carbon dioxide (CO2) - neutral biogas. The biogas thus produced can be used to produce heat, electricity and upgrade to biomethane for vehicle use. The produced biomethane can replace the diesel consumption associated with GHG emission in cane transport.
Sugarcane is one among the most cultivated crop in the world. Australia alone produced nearly 33.5 million tonnes of cane in 2018 (FAO 2018). These large production of sugarcane lead to an increase in crop residues and agro-wastes from the sugarcane industry. In this study, an investigation regarding the anaerobic co-digestion of crop residues and agro-wastes from sugarcane industry viz, sugarcane trash (SCT) or sugarcane bagasse (SCB) with chicken manure (CM) was investigated in a batch experiment at 37 °C. In spite of various researches conducted till date about co-digestion of lignocellulosic waste with manure, no research data was available regarding the effect of feed ratio on co-digestion of SCT/SCB with CM. This research gap was investigated in this study. In addition to this, steam explosion pre-treatment of SCT/SCB was included to investigate how the pre-treatment influence methane yield among different feed ratios of SCT/SCB with CM.
At first, SCT and SCB were subjected to steam explosion pre-treatment (steam impregnation at 130 °C for 5 minutes followed by steam explosion). Later, two sets of biochemical methane potential (BMP) tests were conducted at an Inoculum to Substrate Ratio (ISR) of 2. Co-digestion of untreated and steam exploded SCT or SCB with CM was investigated at feed ratios of 75:25, 50:50 and 25:75 on volatile solids (VS) basis. Assays with 100% untreated and steam exploded SCT or SCB were also included. Chemical analysis revealed that the steam explosion improved the VS content in pre-treated biomass compared with untreated biomass. The increase in VS was 1.6% and 5.7% in SCT and SCB, respectively.
On the other hand, a slight reduction in total solids (TS) of nearly 4% and 1% were observed in the case of SCT and SCB, respectively. BMP results showed that the steam explosion had a profound effect on the methane production rates and yields, especially for SCB than SCT. Methane (CH4) yields of 201.8 and 199 ml CH4/gVSadded were obtained during the mono-digestion of untreated SCT and SCB, respectively. The corresponding values for 100% steam-exploded SCT and SCB were 207.5 and 225.6 ml/gVSadded, respectively. In comparison to mono-digestion, the co-digestion of SCB or SCT with CM did not improve the methane yields.
Nevertheless, pre-treatment improved the methane production rates and yields of pre-treated biomass than untreated biomass. Among the studied feed ratios, best methane yields of 206.5 ml/gVSadded were obtained when steam-exploded SCT was co-digested with CM at 75:25 ratio. However, methane yields decreased with an increase in the amount of CM added. SCB also showed a similar trend. The best methane yield of 199.5 ml/gVSadded was obtained when steam-exploded SCB was co-digested with CM at 75:25 ratio. Among the tested feed ratios, all co-digestion mixtures except for 75:25 and 50:50 ratios of untreated SCT to CM showed synergistic effects. The best synergistic effect of 18.57% was observed when untreated SCB was co-digested with CM at 25:75 ratio. Kinetic modelling results confirmed that the steam explosion pre-treatment improved the methane production rates and yields by increasing the hydrolysis rate constant values. However, a higher hydrolysis rate constant was noticed for SCT than SCB. The highest hydrolysis rate constant of 0.16 d-1 was achieved at feed ratios of 50:50 and 25:75 of pre-treated SCT:CM.
Interestingly, more than 75% of methane in pre-treated assays was produced by Day 11. The study thus suggests that the steam explosion can improve the methane production rates, yields and productivity of SCT and SCB. However, the use of CM as co-substrate did not improve the methane yields when compared to the mono-digestion of SCT or SCB, but a positive synergism was evident in most of the co-digestion feed ratios.Thesis (Masters)
Master of Philosophy (MPhil)
School of Eng & Built Env
Science, Environment, Engineering and Technology
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Liu, Xun. "Valorisation énergétique de la biomasse lignocellulosique par digestion anaérobie : Prétraitement fongique aérobie." Thesis, Lyon, INSA, 2015. http://www.theses.fr/2015ISAL0099/document.
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La bioconversion en méthane de biomasses lignocellulosiques est l’une des alternatives les plus prometteuses pour la production de méthane issu de la digestion anaérobie. Toutefois, les biomasses lignocellulosiques présentent des caractéristiques bio-physico-chimiques très variables en raison leur composition biochimique et de l’organisation structurale très diverses. Par ailleurs, leur faible biodégradabilité en conditions anaérobie nécessite de les prétraiter avant méthanisation pour optimiser la production de méthane. Ce travail vise à évaluer l’influence des caractéristiques d’une large gamme de substrats lignocellulosiques sur leur biodégradabilité anaérobie et les corrélations entre leurs caractéristiques bio-physico-chimiques et le potentiel biométhanogène, et d’étudier les effets du prétraitement fongique en présence de Ceriporiopsis subvermispora sur le potentiel biométhanogène de biomasses lignocellulosiques sélectionnées dans la présente étude et de caractériser les changements de leurs caractéristiques après le prétraitement fongique. La caractérisation de 36 biomasses lignocellulosiques représentatives d’une large gamme de gisements potentiellement mobilisables a permis de mettre en évidence les corrélations linéaires entre le potentiel biométhanogène des biomasses et certaines de leur caractéristiques bio-physico-chimiques, dont la teneur en lignine et la demande biochimique en oxygène. Les biomasses sylvicoles et agricoles ont montré des caractéristiques distinctes de la biodégradabilité aérobie et anaérobie. Les résultats de prétraitement fongique sur les 5 biomasses ont permis de mettre en évidence que le champignon de pourriture blanche Ceriporiopsis subvermispora réagit distinctement selon la biomasse prétraitée. Pour certaines biomasses, le prétraitement fongique conduit à augmenter significativement la production de méthane et la vitesse de bioconversion en méthane. Cette espèce présente la capacité de dégrader sélectivement la lignine sur certaines biomasses et, sur d’autres, celle de dégrader de manière non-sélective des polysaccharides et des lignines. De plus, pour les deux souches de Ceriporiopsis subvermispora testées, des métabolismes différents ont été mis en évidence sur une même biomasse. Les résultats de compositions et ceux de l’analyse structurale des biomasses (initiales, autoclavées, contrôles, et prétraitées par Ceriporiopsis subvermispora) ont montré que leur structure peut être modifiée sans toutefois observer une transformation significative de leur composition biochimiqueBioconversion to methane lignocellulosic biomass is one of the most promising alternatives for the production of methane from anaerobic digestion. However, lignocellulosic biomass has various bio-physicochemical characteristics due to their biochemical composition and diverse structural organization. Moreover, their low biodegradability in anaerobic condition requires pretreatment before methanation to optimize methane production. This work aims to evaluate the influence of the characteristics of a wide range of lignocellulosic substrates on their anaerobic biodegradability and correlations between their bio-physical-chemical characteristics and biomethane potential, and study the effects of fungal pretreatment in the presence of Ceriporiopsis subvermispora on the biogas potential of lignocellulosic biomass selected in this study and characterize their changes of their characteristics before and after the fungal pretreatment. The characterization of 36 representative lignocellulosic biomass of a wide range of potentially mobilized deposits allowed to highlight the linear correlations between biomethane potential of biomass and some of their bio-physical-chemical characteristics, of which the lignin content and biochemical oxygen demand. The forest and agricultural biomass exhibited distinct characteristics of the aerobic and anaerobic biodegradability. The results of fungal pretreatment of the 5 biomass indicated that the white rot fungus Ceriporiopsis subvermispora reacts distinctly depending on the pretreated biomass. For some biomass, fungal pretreatment leads to significant increase of methane production and the bioconversion rate of methane. This species presents the ability to selectively degrade lignin on some biomasses, in others, the ability to non-selectively degrade polysaccharides and lignins. In addition, for both strains of Ceriporiopsis subvermispora tested, different metabolisms were highlighted on the same biomass. The results of compositions and those of the structural analysis of biomass (initials, autoclaved, controls, and pretreated with Ceriporiopsis subvermispora) showed that their structure can be modified without observing a significant transformation of their biochemical composition
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Girisuta, Buana. "Levulinic acid from lignocellulosic biomass." [S.l. : Groningen : s.n. ; University Library Groningen] [Host], 2007. http://irs.ub.rug.nl/ppn/304751316.
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Brandt, Agnieszka. "Ionic liquid pretreatment of lignocellulosic biomass." Thesis, Imperial College London, 2012. http://hdl.handle.net/10044/1/9166.
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This thesis is concerned with the thermal treatment of lignocellulosic biomass using ionic liquids for the purpose of comminution via dissolution, for fractionating the biological composite and for obtaining aqueous solutions of carbohydrate monomers from the pulp via enzymatic hydrolysis. A major focus was the relationship between the choice of the anion and the effectiveness of the treatment. The synthesis of a range of 1-butyl-3-methylimidazolium ionic liquids with strongly hydrogen-bond basic anions was accomplished. Selected, process-relevant physicochemical properties were measured, such as the Kamlet-Taft solvent polarity, hygroscopicity and thermal stability. It was shown that 1-butyl-3-methylimidazolium acetate is not stable at 120°C, while other ionic liquids e.g. 1-butyl-3-methylimidazolium hydrogen sulfate exhibit very good long-term thermal stability. It was shown that hydrogen-bond basic 1-butyl-3-methylimidazolium ionic liquids attract more than stoichiometric quantities of water when exposed to air, suggesting that ionic liquid pretreatment under anhydrous conditions is difficult to achieve. Dissolution of air-dried wood chips in 1-butyl-3-methylimidazolium ionic liquids was attempted. It was shown that the large particle size and the moisture contained in the biomass hamper complete dissolution. The hydrogen-bond basicity of the ionic liquid, described by the Kamlet-Taft parameter ß, was correlated with the ability to expand as well as partially and anisotropically dissolve wood chips. Pretreatment of lignocellulosic biomass with 1-butyl-3- methylimidazolium methyl sulfate, 1-butyl-3-methylimidazolium hydrogen sulfate and 1-butyl-3-methylimidazolium methanesulfonate was explored and high saccharification yields were reported. It was found that successful application of methyl sulfate and hydrogen sulfate ionic liquids requires addition of water and that comparatively high water contents are tolerated. Fractionation of lignocellulose into an insoluble cellulose fraction, a solubilised hemicellulose fraction and a lignin containing precipitate was achieved. The influence of water content, pretreatment time and biomass type on the enzymatic saccharification yield and the extent of hemicellulose solubilisation, hydrolysis and dehydration were examined.
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Samad, Abdul. "SOPHOROLIPID PRODUCTION FROM LIGNOCELLULOSIC BIOMASS FEEDSTOCKs." OpenSIUC, 2015. https://opensiuc.lib.siu.edu/theses/1799.
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The present study investigated the feasibility of production of sophorolipids (SLs) using yeast Candida bombicola grown on hydrolysates derived lignocellulosic feedstock either with or without supplementing oil as extra carbon source. Several researchers have reported using pure sugars and various oil sources for producing SLs which makes them expensive for scale-up and commercial production. In order to make the production process truly sustainable and renewable, we used feedstocks such as sweet sorghum bagasse, corn fiber and corn stover. Without oil supplementation, the cell densities at the end of day-8 was recorded as 9.2, 9.8 and 10.8 g/L for hydrolysate derived from sorghum bagasse, corn fiber, and corn fiber with the addition of yeast extract (YE) during fermentation, respectively. At the end of fermentation, the SL concentration was 3.6 g/L for bagasse and 1.0 g/L for corn fiber hydrolysate. Among the three major sugars utilized by C. bombicola in the bagasse cultures, glucose was consumed at a rate of 9.1 g/L-day; xylose at 1.8 g/L-day; and arabinose at 0.98 g/L-day. With the addition of soybean oil at 100 g/L, cultures with bagasse hydrolysates, corn fiber hydrolysates and standard medium had a cell content of 7.7 g/L; 7.9 g/L; and 8.9 g/L, respectively after 10 days. The yield of SLs from bagasse hydrolysate was 84.6 g/L and corn fiber hydrolysate was15.6 g/L. In the same order, the residual oil in cultures with these two hydrolysates was 52.3 g/L and 41.0 g/L. For this set of experiment; in the cultures with bagasse hydrolysate; utilization rates for glucose, xylose and arabinose was recorded as 9.5, 1.04 and 0.08 g/L-day respectively. Surprisingly, C. bombicola consumed all monomeric sugars and non-sugar compounds in the hydrolysates and cultures with bagasse hydrolysates had higher yield of SLs than those from a standard medium which contained pure glucose at the same concentration. Based on the SL concentrations and considering all sugars consumed, the yield of SLs was 0.55 g/g carbon (sugars plus oil) for cultures with bagasse hydrolysates. Further, SL production was investigated using sweet sorghum bagasse and corn stover hydrolysates derived from different pretreatment conditions. For the former and latter sugar sources, yellow grease or soybean oil was supplemented at different doses to enhance sophorolipid yield. 14-day batch fermentation on bagasse hydrolysates with 10, 40 and 60 g/L of yellow grease had cell densities of 5.7 g/L, 6.4 g/L and 7.8 g/L, respectively. The study also revealed that the yield of SLs on bagasse hydrolysate decreased from 0.67 to 0.61 and to 0.44 g/g carbon when yellow grease was dosed at 10, 40 and 60 g/L. With aforementioned increasing yellow grease concentration, the residual oil left after 14 days was recorded as 3.2 g/L, 8.5 g/L and 19.9 g/L. For similar experimental conditions, the cell densities observed for corn stover hydrolysate combined with soybean oil at 10, 20 and 40 g/L concentration were 6.1 g/L, 5.9 g/L, and 5.4 g/L respectively. Also, in the same order of oil dose supplemented, the residual oil recovered after 14-day was 8.5 g/L, 8.9 g/L, and 26.9 g/L. Corn stover hydrolysate mixed with the 10, 20 and 40 g/L soybean oil, the SL yield was 0.19, 0.11 and 0.09 g/g carbon. Overall, both hydrolysates supported cell growth and sophorolipid production. The results from this research show that hydrolysates derived from the different lignocellulosic biomass feedstocks can be utilized by C. bombicola to achieve substantial yields of SLs. Based upon the results revealed by several batch-stage experiments, it can be stated that there is great potential for scaling up and industrial scale production of these high value products in future.
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Borén, Eleonora. "Off-gassing from thermally treated lignocellulosic biomass." Doctoral thesis, Umeå universitet, Institutionen för tillämpad fysik och elektronik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-141921.
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Off-gassing of hazardous compounds is, together with self-heating and dust explosions, the main safety hazards within large-scale biomass storage and handling. Formation of CO, CO2, and VOCs with concurrent O2 depletion can occur to hazardous levels in enclosed stored forest products. Several incidents of CO poisoning and suffocation of oxygen depletion have resulted in fatalities and injuries during cargo vessel discharge of forest products and in conjunction with wood pellet storage rooms and silos. Technologies for torrefaction and steam explosion for thermal treatment of biomass are under development and approaching commercialization, but their off-gassing behavior is essentially unknown. The overall objective of this thesis was to provide answers to one main question: “What is the off-gassing behaviour of thermally treated lignocellulosic biomass during storage?”. This was achieved by experimental studies and detailed analysis of off-gassing compounds sampled under realistic conditions, with special emphasis on the VOCs. Presented results show that off-gassing behavior is influenced by numerous factors, in the following ways. CO, CO2 and CH4 off-gassing levels from torrefied and stream-exploded biomass and pellets, and accompanying O2 depletion, are comparable to or lower than corresponding from untreated biomass. The treatments also cause major compositional shifts in VOCs; emissions of terpenes and native aldehydes decline, but levels of volatile cell wall degradation products (notably furans and aromatics) increase. The severity of the thermal treatment is also important; increases in torrefaction severity increase CO off-gassing from torrefied pine to levels comparable to emissions from conventional pellets, and increase O2 depletion for both torrefied chips and pellets. Both treatment temperature and duration also influence degradation rates and VOC composition. The product cooling technique is influential too; water spraying in addition to heat exchange increased CO2 and VOCs off-gassing from torrefied pine chips, as well as O2 depletion. Moreover, the composition of emitted gases co-varied with pellets’ moisture content; pellets of more severely treated material retained less moisture, regardless of their pre-conditioning moisture content. However, no co-variance was found between off-gassing and pelletization settings, the resulting pellet quality, or storage time of torrefied chips before pelletization. Pelletization of steam-exploded bark increased subsequent VOC off-gassing, and induced compositional shifts relative to emissions from unpelletized steam-exploded material. In addition, CO, CO2 and CH4 off-gassing, and O2 depletion, were positively correlated with the storage temperature of torrefied softwood. Similarly, CO and CH4 emissions from steam-exploded softwood increased with increases in storage temperature, and VOC off-gassing from both torrefied and steam-exploded softwood was more affected by storage temperature than by treatment severity. Levels of CO, CO2 and CH4 increased, while levels of O2 and most VOCs decreased, during storage of both torrefied and steam-exploded softwood.CO, CO2 and O2 levels were more affected by storage time than by treatment severity. Levels of VOCs were not significantly decreased or altered by nitrogen purging of storage spaces of steam-exploded or torrefied softwood, or controlled headspace gas exchange (intermittent ventilation) during storage of steam-exploded bark. In conclusion, rates of off-gassing of CO and CO2 from thermally treated biomass, and associated O2 depletion, are comparable to or lower than corresponding rates for untreated biomass. Thermal treatment induces shifts in both concentrations and profiles of VOCs. It is believed that the knowledge and insights gained provide refined foundations for future research and safe implementation of thermally treated fuels as energy carriers in renewable energy process chains.
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Corredor, Deisy Y. "Pretreatment and enzymatic hydrolysis of lignocellulosic biomass." Diss., Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/693.
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Håseth, Jenny Kristin. "Decrystallization of Lignocellulosic Biomass using Ionic Liquids." Thesis, Norges Teknisk-Naturvitenskaplige Universitet, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-21106.
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This thesis is written in fulfilment of the requirements for a Master in Science at the Norwegian University of Science and Technology (NTNU), Department of Chemical Engineering. The work investigates the effectiveness of pretreatment of norway spruce and sugarcane bagasse with the ionic liquid 1-ethyl-3-methylimidazolium acetate ([EMIM][OAc]). The effect of pretreatment temperature and reaction time was evaluated. Enzymatic hydrolysis yield was used as the main evaluation parameter. Norway spruce was pretreated at 80, 100, and 120 °C for 3, 6, 12, and 24 hours. The sugarcane bagasse raw material was pretreated at the same temperatures for 1 and 3 hours. UV-Vis spectrophotometric analysis was used to determine the amount of lignin removed during the pretreatment. The regenerated solids from the pretreatment was hydrolysed enzymaticly and the digestibility was determined using High-Performance Liquid Chromatography (HPLC). The pretreatment caused an increase in the enzymatic digestibility for both spruce and bagasse. This effect is believed to arise from a decrease in the crystallinity of the cellulose and an increase in the accessible surface area caused by the increased porosity of the pretreated material.The digestibility results for spruce shows that, at shorter pretreatment times, higher temperatures are favourable. However, at longer reaction times, too high temperatures can give a reduction in the digestibility. The optimal reaction condition for spruce was in this work found to be 100 °C for 12 hours, giving a digestibility close to 90 wt% of the added glucan. For sugarcane bagasse the optimum was not found, and experiments using harsher conditions was proposed. When comparing the results for pretreatment of spruce with that of bagasse it appear that spruce needs harsher conditions to achieve the same glucan yield as bagasse. The results of the analysis of the enzymatic digestibility of hemicelluloses (mannan for spruce and zylan for bagasse) concurs very well with the results for glucan presented above.Regarding the removal of lignin from the biomass, it was found that the degree of delignification in these pretreatment experiments was so low it could be neglected. The low degree of lignin removal was also evident in the darkening of the regenerated biomass from pretreatments using relatively harsh reaction conditions. This darkening was put down to the lignin undergoing condensation reactions. Suggestions for further work on this area include a thorough investigation into the thermal stability of different ionic liquids at prolonged reaction times and high temperatures, as well as an investigation of the delignification effect of different ionic liquids. As mentioned earlier, pretreatment experiments with bagasse using harsher conditions can also be useful.
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Frazão, Cláudio José Remédios. "Challenges of ethanol production from lignocellulosic biomass." Master's thesis, Universidade de Aveiro, 2014. http://hdl.handle.net/10773/13657.
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Mestrado em Biotecnologia - Biotecnologia Industrial e AmbientalThe present work aimed to tackle two of the major challenges in bioethanol production from lignocellulosic feedstocks: (i) high tolerance of microorganisms to lignocellulosic inhibitors, and (ii) microbial contamination avoidance. Lignocellulosic inhibitors are an important fraction of spent sulphite liquor (SSL), a by-product of the pulp and paper industries. Hardwood SSL (HSSL) is rich in pentose sugars, mainly xylose, which can be converted to ethanol by the yeast Scheffersomyces stipitis. In this work, a population of S. stipitis previously adapted to 60 % (v/v) of HSSL was used, and its stability on the absence of inhibitors during ten sequential transfers was investigated at single-clone level. During the screening trials, all the isolated clones showed higher xylose and acetate uptake rates and lower ethanol productivities than the parental strain. The clone exhibiting higher xylose uptake rate (0.558 g L-1 h-1) was named isolate C4. The effect of short-term adaptation on isolate C4 fermentation performance was evaluated by pre-cultivating the clone in the presence or absence of 60 % (v/v) of HSSL. The uptake rates of glucose and xylose were similar under both conditions, but a higher acetate consumption rate (0.101 g L-1 h-1) and maximum ethanol concentration (4.51 g L-1) were achieved without pre-adaptation step, suggesting the robustness of isolate C4. The industrial bioethanol production is mostly carried out under non-sterile conditions, which favours microbial contamination. In this work, the mechanism that triggers Lactobacillus pentosus contamination in SSL plants was investigated. A simulated synthetic hydrolysate mimicking the average composition of sugars and inhibitors of softwood SSL (SSSL) was used and the impact of different factors in bacterial and Saccharomyces cerevisiae viability was analysed. The presence of yeast extract led to an increase in lactate production (9-fold higher) and L. pentosus viability when only bacteria was inoculated. Using different inoculation ratios of yeast/bacteria, the ethanol production rates were not affected after 48 h, and L. pentosus failed to overtake S. cerevisiae. The presence of inhibitors delayed yeast growth, but the bacteria did not outcompete S. cerevisiae. When the pH was optimal to L. pentosus in co-culture experiments, the bacterial cell viability decreased slower. The results indicate that L. pentosus was unable to overtake S. cerevisiae. The presence of yeast extract and favourable pH to bacteria are important factors that can play a role in the mechanism that triggers the bacterial contamination in ethanol plants.
A presente dissertação tem como objetivo abordar dois dos maiores desafios na produção de bioetanol a partir de biomassa lenhocelulósica: (i) elevada tolerância de microrganismos a inibidores, e (ii) prevenção de contaminação microbiana. Os inibidores lenhocelulósicos são uma fração relevante do licor de cozimento ao sulfito ácido (SSL), um subproduto das indústrias do papel e pastas. O SSL de folhosas (HSSL) é rico em pentoses, principalmente xilose, que podem ser fermentadas em etanol pela levedura Scheffersomyces stipitis. Neste estudo, utilizou-se uma população de S. stipitis previamente adaptada a 60 % (v/v) HSSL, e avaliou-se a sua estabilidade na ausência de inibidores durante dez transferências sequenciais. Comparando com a estirpe original, todos os clones isolados exibiram taxas de consumo de xilose e ácido acético superiores e produtividades em etanol inferiores. O clone que demonstrou a maior taxa de consumo de xilose (0,558 g L-1 h-1) foi designado isolado C4, e o efeito de adaptação de curta duração no seu desempenho fermentativo foi investigado através do seu pré-cultivo na presença ou ausência de 60 % (v/v) HSSL. Nas duas condições, as taxas de consumo de glucose e xilose foram idênticas, contudo, atingiu-se maior taxa de consumo de ácido acético (0,101 g L-1 h-1) e maior concentração máxima de etanol (4,51 g L-1) foram atingidas na ausência do processo de adaptação de curta duração. Tais resultados demonstram a robustez do isolado C4. A maioria dos processos de produção industrial de bioetanol é realizada na ausência de esterilidade, favorencendo a contaminação por microrganismos. Neste estudo, investigou-se o mecanismo responsável pela contaminação com Lactobacillus pentosus na indústria de SSL. Para tal, utilizou-se um hidrolisado sintético mimetizando a composição média de açúcares e inibidores de SSL de resinosas (SSSL) e averiguou-se o impacto de vários fatores na viabilidade de L. pentosus e S. cerevisiae. A presença de extrato de levedura foi responsável pelo aumento da produção de ácido lático (9 vezes) e da viabilidade bacteriana quando L. pentosus foi cultivado na ausência de levedura. Diferentes proporções de inóculo de levedura/bactéria não afetaram a produção de etanol após 48 h de fermentação, e L. pentosus foi incapaz de ser a estirpe dominante durante os ensaios de co-cultura. A presença de inibidores retardou o crescimento da levedura, mas a bactéria foi de novo incapaz de se a espécie dominante. Ajustando o valor de pH para o ótimo de L. pentosus nos ensaios de co-cultura, a viabilidade celular da bactéria diminuiu mais lentamente. Os resultados demonstram que L. pentosus não foi a espécie dominante nos ensaios de co-cultura. A presença de extrato de levedura e de valores de pH favoráveis a L. pentosus podem desempenhar um papel importante no mecanismo responsável pela contaminação bacteriana nas indústrias de produção de bioetanol.
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Luccarini, Cristina. "Studio sperimentale dell'effetto di pretrattamenti termici, fisici e chimici sulla digestione anaerobica di biomasse lignocellulosiche." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2019.
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Lo studio riguarda la valutazione dell’effetto di pretrattamenti termici, chimici e fisici sull’efficienza di conversione di biomasse lignocellulosiche di scarto (sfalci e potature di verde urbano e privato) in biometano. I risultati di laboratorio hanno mostrato che il pretrattamento che dà la resa più alta di conversione è la steam explosion; infatti ha permesso di ottenere una resa in biometano pari al 52% della resa teorica. La steam explosion è stata applicata agli sfalci e potature, poi somministrati ad un impianto sperimentale di digestione anaerobica. In questa fase sperimentale (di conduzione continua durata 9 mesi) è stata coinvolta Hera Ambiente Spa: i primi mesi il digestore è stato alimentato con biomassa lignocellulosica tal quale e successivamente con il medesimo tipo di biomassa sottoposta a steam explosion. Sono state eseguite analisi sul biogas, sulla biomassa in entrata e in uscita, ed è stata monitorata la composizione del gas e la concentrazione dei VFA. La prima fase dello studio ha mostrato performance soddisfacenti, prossime a quelle osservate nei test in batch. Successivamente la performance è peggiorata, con un rallentamento della produzione di gas ed un progressivo incremento della concentrazione di VFA, fino ad arrivare a poche settimane dalla fine dello studio in cui il digestore è entrato in condizione di acidosi. La resa in CH4 a fine studio è risultata pari al 27% del metano teorico producibile. La causa probabile di tale risultato è stata l’elevato contenuto di carbonio rispetto all’azoto della biomassa: il rapporto C/N dalle analisi elementari è risultato pari a 53, che non rientrando nell’intervallo 20-30 ottimale per la digestione anaerobica, può determinare sul lungo periodo, un’attività biologica ridotta. Una delle soluzioni è quella di operare una co-digestione dei materiali di scarto lignocellulosici con materiali di scarto dell’industria zootecnica, che contrariamente presentano un rapporto C/N compreso tra 10-20.
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Gan, Jing. "Hydrothermal conversion of lignocellulosic biomass to bio-oils." Diss., Kansas State University, 2012. http://hdl.handle.net/2097/13768.
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Doctor of PhilosophyDepartment of Biological and Agricultural Engineering
Wenqiao Yuan
Donghai Wang
Corncobs were used as the feedstock to investigate the effect of operating conditions and crude glycerol (solvent) on bio-oil production. The highest bio-oil yield of 33.8% on the basis of biomass dry weight was obtained at 305°C, 20 min retention time, 10% biomass content, 0.5% catalyst loading. At selected conditions, bio-oil yield based on the total weight of corn cobs and crude glycerol increased to 36.3% as the crude glycerol/corn cobs ratio increased to 5. Furthermore, the optimization of operating conditions was conducted via response surface methodology. A maximum bio-oil yield of 41.3% was obtained at 280°C, 12min, 21% biomass content, and 1.56% catalyst loading. A highest bio-oil carbon content of 74.8% was produced at 340°C with 9% biomass content. A maximum carbon recovery of 25.2% was observed at 280°C, 12min, 21% biomass content, and 1.03% catalyst loading. The effect of biomass ecotype and planting location on bio-oil production were studied on big bluestems. Significant differences were found in the yield and elemental composition of bio-oils produced from big bluestem of different ecotypes and/or planting locations. Generally, the IL ecotype and the Carbondale, IL and Manhattan, KS planting locations gave higher bio-oil yield, which can be attributed to the higher total cellulose and hemicellulose content and/or the higher carbon but lower oxygen contents in these feedstocks. Bio-oil from the IL ecotype also had the highest carbon and lowest oxygen contents, which were not affected by the planting location. In order to better understand the mechanisms of hydrothermal conversion, the interaction effects between cellulose, hemicellulose and lignin in hydrothermal conversion were studied. Positive interaction between cellulose and lignin, but negative interaction between cellulose and hemicellulose were observed. No significant interaction was found between hemicelluose and lignin. Hydrothermal conversion of corncobs, big bluestems, switchgrass, cherry, pecan, pine, hazelnut shell, and their model biomass also were conducted. Bio-oil yield increased as real biomass cellulose and hemicellulose content increased, but an opposite trend was observed for low lignin content model biomass.
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Lopes, André Miguel da Costa. "Pre-treatment of lignocellulosic biomass with ionic liquids." Master's thesis, Universidade de Aveiro, 2012. http://hdl.handle.net/10773/9521.
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Mestrado em BiotecnologiaO objetivo deste trabalho foi estudar o pré-tratamento de biomassa lignocelulósica, como a palha de trigo, usando líquidos iónicos (LIs) de modo a obter a separação dos principais componentes, nomeadamente, celulose, hemicelulose e lignina. O processo de pré-tratamento foi otimizado com base em duas metodologias descritas na literatura utilizando o líquido iónico acetato de 1-etil-3-metilimidazólio ([emim][CH3COO]). A metodologia otimizada permitiu separar as frações ricas em hidratos de carbono das frações de lignina, ambas com elevada pureza, e com uma recuperação de LIs até um máximo de 97% da sua massa inicial. Desta forma, o LI pode ser reusado confirmando a flexibilidade do processo desenvolvido. A versatilidade do método foi testada com a investigação de três líquidos iónicos diferentes, nomeadamente hidrogenossulfato de 1-butil-3-metilimidazólio ([bmim][HSO4]), tiocianato de 1-butil-3-metilimidazólio ([bmim][SCN]) e dicianamida de 1-butil-3-metilimidazólio ([bmim][N(CN)2]). No processo de dissolução de palha de trigo observou-se uma dissolução completa a nível macroscópico apenas para os líquidos iónicos [emim][CH3COO] e [bmim][HSO4]. O [emim][CH3COO] apresentou maior eficiência no processo de dissolução e regeneração da biomassa. Contrariamente, o [bmim][SCN] demonstrou ser o menos eficiente em todo o processo de pré-tratamento. Um comportamento diferente foi observado para o [bmim][HSO4], cujo pré-tratamento apresentou similaridades a uma hidrólise ácida. Os pré-tratamentos com [bmim][HSO4] e [bmim][N(CN)2] permitiram a obtenção de frações ricas em celulose com um conteúdo em hidratos de carbono de 87 a 90%. Para as frações ricas em celulose provenientes do pré-tratamento com [emim][CH3COO] foram efetuados ensaios de hidrólise enzimática para verificar a potencial aplicação destas frações, bem como, avaliar a eficiência das metodologias de pré-tratamento estudadas. Os resultados obtidos demonstraram elevado índice de digestibilidade da celulose e confirmou o elevado teor de glucose presente na fração celulósica obtida pela metodologia otimizada. A técnica de Espectroscopia de Infravermelho com Transformadas de Fourier (FT-IR) permitiu efetuar análises qualitativas e quantitativas de todas as amostras obtidas nos pré-tratamentos realizados. Para avaliar a pureza dos LIs após os pré-tratamentos utilizou-se a técnica espectroscópica de ressonância magnética nuclear (RMN). Os resultados provenientes dos ensaios de hidrólise enzimática foram obtidos através da técnica cromatográfica de HPLC.
This work is devoted to the pre-treatment of lignocellulosic biomass using ionic liquids (ILs) to separate cellulose, hemicellulose and lignin fractions. Particularly, research was focused on studying the influence of various ILs on the pre-treatment of wheat straw. The pre-treatment procedure was optimised basing on two methodologies presented in the literature. In the optimised method 1-ethyl-3-methylimidazolium acetate ([emim][CH3COO]) IL was used. The developed method is beneficial as allows a separation of highly-purified carbohydrate and lignin-rich samples and permits to recover ILs with a yield of 97wt%. Therefore, the IL could be reused confirming a great flexibility of the developed method. Furthermore, versatility of the method was confirmed by examination of different ILs such as 1-butyl-3-methylimidazolium hydrogensulfate ([bmim][HSO4]), 1-butyl-3-methylimidazolium thiocyanate ([bmim][SCN]) and 1-butyl-3-methylimidazolium dicyanamide ([bmim][N(CN)2]). Only [emim][CH3COO] and [bmim][HSO4] ILs were found to be capable to achieve a macroscopic complete dissolution of wheat straw. Considering dissolution and regeneration process, [emim][CH3COO] was the most efficient among investigated ILs. On the contrary, [bmim][SCN] demonstrated the lowest efficiency either in dissolution and regeneration or fractionation processes. The [bmim][HSO4] showed different behaviour from other ILs exhibiting similarities to acid hydrolysis pre-treatment. Pre-treatments with [bmim][HSO4] and [bmim][N(CN)2] allowed to recover cellulose rich-samples with a carbohydrate content between 87 to 90wt%. In order to verify the potential further applicability of obtained carbohydrate-rich fractions as well as to evaluate the pre-treatment efficiency, the cellulose-rich fraction obtained from treatment with [emim][CH3COO] was applied for the enzymatic hydrolysis. Achieved results showed a high digestibility of cellulose-rich samples and confirmed a high glucose yield for the optimised methodology. Qualitative and quantitative analyses of the pre-treatment with ILs were made using the Fourier-Transform Infrared Spectroscopy (FT-IR). The NMR analysis was used to evaluate the purity of ILs after pre-treatments. Results of enzymatic hydrolysis analysis were controlled by the HPLC.
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Busby, David Preston. "The cost of producing lignocellulosic biomass for ethanol." Master's thesis, Mississippi State : Mississippi State University, 2007. http://library.msstate.edu/etd/show.asp?etd=etd-07052007-124350.
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Tyufekchiev, Maksim V. "Reaction Engineering Implications of Using Water for the Conversion of Lignocellulosic Biomass." Digital WPI, 2019. https://digitalcommons.wpi.edu/etd-dissertations/563.
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Conversion of lignocellulosic biomass via hydrolysis of cellulose to simple sugars has failed to achieve economic competitiveness to produce renewable fuels and chemicals partly due to the inherent recalcitrance of the substrate and partly due to the use of non-recyclable catalysts. Solid acids have been proposed for cellulose hydrolysis as a recyclable alternative to enzymes and homogeneous acids. However, their catalytic mechanism has not been elucidated partly due to incomplete structural characterization. We focused on elucidating the structure of chloromethyl polystyrene based catalysts which exhibit remarkable activity towards hydrolyzing cellulose. By carrying out spatially resolved analysis of CMP-SO3H-0.3, a catalyst decorated with benzyl chloride and benzyl sulfonic acid groups, we discovered that the external surface of the catalyst is devoid of any chloride groups, which were hypothesized to interact with cellulose. Despite apparent greater reactivity than sulfonated-only catalysts, we found the CMP-SO3H-0.3 reacts with water at the reaction conditions used for cellulose hydrolysis, resulting in leaching of homogeneous hydrochloric acid, which in turn is responsible for the observed cellulose hydrolysis. Building on these results we investigated whether catalysts from various structural classes are stable in the hydrothermal environment or leach homogeneous acid. Surprisingly, we discovered that materials commonly used for cellulose hydrolysis are hydrothermally unstable and the leached homogeneous acid they produced was responsible for their apparent catalytic activity. On the other hand, hydrothermally stable materials did not exhibit greater hydrolysis activity than water. Cellulose crystallinity has been theorized for decades as a structural parameter determining the reactivity of cellulose, which motivated decrystallization pretreatment processes. However, water-induced recrystallization had not been accounted for in hydrolysis models, albeit being a well-documented phenomenon, and all hydrolysis processes use water as a reaction medium. By carrying out detailed structure-reactivity analysis we concluded that decrystallized cellulose undergoes a rapid transformation to an active crystalline cellulose, characterized by allomorphs I and II and greater content of surface polymer chains. Water-induced recrystallization reduced the reactivity of cellulose and prevented conversion of highly reactive amorphous regions. To circumvent the recrystallization pathway, we used ethanolysis as a means for rapid and selective depolymerization of amorphous cellulose. Ethanolysis of ball-milled cellulose for 30 minutes at 410 K resulted in 38% conversion, while hydrolysis at the same conditions in only 15%. Scission-relaxation caused recrystallization and limited conversion via ethanolysis. By using co-solvents capable of swelling cellulose, we were able to increase cellulose conversion to 48%. The results presented in those studies can guide future development of catalysts and depolymerization processes that circumvent the inhibiting effects caused by the use of water.
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Gupta, Shelaka. "Catalytic conversion of biomass-derived platform molecules : mechanistic insights, fundamental challenges and opportunities for rational catalyst design." Thesis, IIT Delhi, 2019. http://eprint.iitd.ac.in:80//handle/2074/8074.
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Mu, Wei. "Aqueous phase processing of lignocellulosic biomass for biofuel production." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53075.
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This thesis studied the catalytic upgrading of pyrolysis oil derived from both ethanol organosolv (EOL) lignin and whole biomass. There are four major components of this thesis. In the first part, several lignin model compounds and the commonly used noble metal catalysts were evaluated. During the reaction, coke formation deactivated several catalysts. The reaction pathway of the coke formation was proposed. Ruthenium/activated carbon can hydrogenate the aromatic ring and remove the methoxyl group as well due to its unique catalytic behavior. The reaction mechanism was deduced based on the products distribution of the model compounds. The second part of this study focuses on the catalytic HDO reaction with real EOL pyrolysis oil. The results indicate the reaction mechanism with EOL pyrolysis oil is similar to the results of the model compound study. Due to the deactivation of the Ru/C catalyst by tar produced during the upgrading, two-step hydrodeoxygenation at different temperature was adopted in this study. The second part mainly discussed the first-step HDO reaction. The upgraded pyrolysis oil was analyzed using GC-MS, ¹H, ¹³C, and HSQC ²D NMR. The chemical structure change after the first-step upgrading and the cleavage of the inter-linkages were included. The third part focuses on the product analysis after the second-step HDO. All the products were completely hydrogenated. The molecular weight of the upgraded oil is in the monomer range and the GC-MS study provided detailed compound structures. However, some of them still contain oxygen atoms. To produce completely deoxygenated products, alkali treated ZSM-5 was used as a supporting material and it was effective in catalyzing the dehydration reaction and producing deoxygenated compounds. In the fourth part, light oil derived from whole biomass also underwent treatment under the same HDO reaction conditions as those used in upgrading EOL pyrolysis oil. In this reaction, the biomass were separated into three components: stem, residue and bark. The compound structures of the three different types of light oil were analyzed by GC, ¹H and ¹H-¹³C HSQC-NMR. Then the light oil was processed under the same condition as the heavy oil upgrading. The reaction mechanisms with cellulose and hemicellulose were also studied. These results will be of value in developing of complete hydrogenation of whole biomass pyrolysis oils.
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Queirós, Carla Sofia Gonçalves Pereira. "Lignocellulosic biomass for a new generation of thermal fluids." Doctoral thesis, ISA/UL, 2019. http://hdl.handle.net/10400.5/18319.
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Doutoramento em Engenharia Florestal e dos Recursos Naturais - Instituto Superior de Agronomia / ULThe increasing demand for fossil fuels, conjugated with the decreasing in oil reserves, led to a sharp rise of chemicals and materials derived from petroleum. Resulting in an increase desire from industry to seek for sustainable and alternative sources for key commodity chemicals or suitable equivalents Plant biomass represents one of the most important renewable energy sources for Europe, however much of the lignocellulosic biomass is often disposed of by burning, even in the rich and developed countries. Although, in the past years, there have been a strong effort in the research and valorisation of these residues. Therefore, lignocellulosic biomass can potentially be converted into different high value products including bio-fuels, value added fine chemicals, and cheap energy sources for microbial fermentation and enzyme production. The growing awareness of the need for energy efficiency gains requires new approaches for problems that, during the time of cheap energy and unlimited raw materials resources, were not the object of special care for industry and consequently, for research. In the case of heat and mass transfer, the increase in efficiency must be promoted by using new heat transfer fluids. Recently, ionic liquids (ILs) have proven to be suitable alternatives for many applications in industry and chemical manufacturing, even in the field of heat transfer and energy storage. Namely, the suspension of nanomaterials in ionic liquids proved to increase the thermal conductivity of the IoNanofluid in relation to the base ionic liquid. ILs have also being study in several biomass processes, particularly in the dissolution of cellulose
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Samayam, Indira Priya. "Characterization and Saccharification of Ionic Liquid Pretreated Lignocellulosic Biomass." University of Toledo / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1313700629.
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Wood, Brent E. "Improving Klebsiella oxytoca for ethanol production from lignocellulosic biomass." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0011422.
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Lanigan, Brigid. "Microwave processing of lignocellulosic biomass for production of fuels." Thesis, University of York, 2010. http://etheses.whiterose.ac.uk/1237/.
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Current environmental issues and resource demands are driving the global development of renewable energy. The work described in this thesis applies green and energy efficient microwave technology to transform lignocellulosic biomass into solid and liquid fuels suitable for application in coal burning power plants or upgrading into transportation fuels. Current thermochemical biofuel production (e.g. pyrolysis and gasification) suffer many drawbacks such as high energy consumption and poor flexibility. Herein, it is shown that by applying novel low temperature microwave processing, fuels can be produced at temperatures up to 190 oC lower than required in equivalent conventional thermal treatments. Studies on the microwave activation of the major components of biomass give insight into the mode of action. 180 oC was identified as the key temperature in the degradation of cellulose. Softening of the amorphous region of cellulose at this temperature enables microwave induced rearrangement increasing the efficiency of microwave interaction resulting in acid catalysed decomposition. It was shown possible to produce high calorific value chars at 150 oC lower than previously expected. A reduction of 100 oC was observed in the degradation temperature of hemicellulose. The technology is versatile, effective on a variety of biomass species, and has a favourable energy balance. In studies on whole biomass, the processing conditions and energy usage were found to be favourable when compared with conventional methods. Chars were produced at low temperatures with increased calorific values and material properties in parallel with high quality bio-oils. Pilot scale trials were also carried out proving the technology to be scalable and open to industrial application. This thesis shows for the first time the possibility to produce biofuels via microwave processing, while operating at temperatures below 300 oC. The impact of these findings is being further investigated at the dedicated microwave facility at the University of York.
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Valenzuela, Mariefel Bayta. "Batch Aqueous-phase Reforming of Lignocellulosic Biomass for Hydrogen Production." Thesis, Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/11624.
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Aqueous-phase reforming (APR) is reported for the first time for the production of H2 from actual biomass. The experiments are carried out in batch using a 100mL Parr microreactor heated to 225C. In this one-pot, two-step process, acid hydrolysis is used to break down the polymeric constituents of biomass to smaller soluble molecules and these species are reformed using a Pt/Al2O3 catalyst. The experiments show that increasing the acid concentration from 1% to 5% causes more than a twelve-fold increase in H2 concentration, with hydrogen a minor product accounting for 18% of the non-condensable gas phase and CO2 as the major product. In the presence of the Pt/Al2O3 reforming catalyst, both the selectivity and yield of hydrogen in the gas phase increase. This is accompanied by a noticeable decrease in carbon monoxide production. Comparison with other feeds such as glucose, wastepaper and ethylene glycol showed that the amount of hydrogen produced from biomass is of a comparable magnitude per gram of feed, although biomass yields more hydrogen per gram of carbohydrate than either glucose or wastepaper. Baseline experiments with only the catalysts in the absence of any biomass show no increase in the reactor system pressure when only water and helium are present, indicating that the observed hydrogen produced is sourced form the biomass.
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Dutta, Baishali. "Assessment of Pyrolysis techniques of lignocellulosic biomass for Biochar production." Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=95255.
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Biomass pyrolysis at temperatures above 300°C, with the biochar being returned to the soil is a possible strategy for climate change mitigation and reducing fossil fuel consumption. In this study, an attempt has been made to develop a finite element model (FEM) in order to couple thermal heating and heat and mass transfer phenomena during pyrolysis. This numerical modelling and simulation approach helped the visualization of the process and optimized the production of biochar. In this work, cylindrical sections of birch wood biomass were pyrolysed in a laboratory-scale thermal desorption unit. The influences of final pyrolysis temperature, heating rate, and pyrolysis atmosphere on the product yields were investigated. Results showed that the yield of pyrolysis products was reduced with increasing time and temperature. On the other hand, the char content in the wood increased together with increasing pyrolysis temperature as well as time for both slow and fast pyrolysis. A technique to maximize the amount of char in the product was also identified through this study and optimized along with the yield. The resulting biochar was tested through proximate analysis and differential scanning calorimetry to determine its thermodynamic qualities, which were analysed and compared according to their physical characteristics like porosity and reflectance.La pyrolyse de biomasse à des températures excédant 300°C, suivi d'un retour au sol du produit de carbonisation de matériel biologique, s'avère une stratégie permettant de possiblement atténuer le changement climatique et réduire la consommation de combustibles fossiles. Dans la présente étude, nous tentâmes de créer un modèle d'éléments finis (MEF) permettant de coupler le réchauffement thermique et les phénomènes de transfert de chaleur et de masse opérant durant la pyrolyse. Cette démarche de modélisation et simulation numérique améliora notre habilité à visualiser le procédé et à optimiser la production de biochar. Des sections cylindriques de biomasse de bois de bouleau furent soumises à une pyrolyse dans un désorbeur thermique de laboratoire. L'influence de la température finale de pyrolyse, la vitesse d'élévation de température, et l'atmosphère de pyrolyse fut investiguée. Les résultants démontrèrent que tandis que le rendement en produits de pyrolyse diminua avec une augmentation de la température et du temps de la pyrolyse, le contenu en charbon du bois augmenta avec une augmentation ces paramètres, tout autant pour une pyrolyse lente qu'une pyrolyse rapide. A travers cette démarche, nous identifiâmes une technique permettant de maximiser la quantité de charbon dans les produits de pyrolyse ainsi que le rendement global du procédé. Le biochar ainsi généré fut testé par analyse immédiate et analyse calorimétrique à compensation de puissance afin de déterminer ses propriétés thermodynamiques, qui furent analysées et comparées selon les caractéristiques physiques des différents biochars, soit leur porosité et leur réflectance. fr
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Maddi, Balakrishna. "Pyrolysis Strategies for Effective Utilization of Lignocellulosic and Algal Biomass." University of Toledo / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1418340334.
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Maitan-alfenas, Gabriela Piccolo. "Enzymatic hydrolysis of lignocellulosic biomass for second generation ethanol production." Universidade Federal de Viçosa, 2014. http://www.locus.ufv.br/handle/123456789/6684.
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A produção de etanol de segunda geração apresenta grande potencial para ser uma realidade sustentável, especialmente no Brasil que prossui grandes quantidades de bagaço de cana-de-açúcar. Os maiores obstáculos deste processo são os pré- tratamentos e a hidrólise da biomassa, principalmente esta última etapa visto que as enzimas ainda apresentam custos muito elevados. Assim, esforços têm se concentrado em tornar o processo mais econômico com a descoberta de enzimas mais efetivas. Novas fontes de enzimas são continuamente encontradas e várias estratégias de prospecção e produção enzimática têm sido estudadas. Uma estratégia bastante utilizada na busca por novas enzimas e/ou enzimas mais eficientes é a análise de genômica comparativa de diferentes micro-organismos que permite a seleção de vários candidatos de interesse num curto período de tempo. Além disso, as enzimas podem ser produzidas por fungos quando estes são crescidos em biomassas que apresentam baixo custo e alta disponibilidade. Este trabalho foi dividido em cinco capítulos sendo que o primeiro consiste de uma revisão atual sobre a produção de etanol de segunda geração focada na etapa de sacarificação enzimática. Várias estratégias de prospecção e produção enzimáticas foram discutidas e detalhadas. No segundo capítulo, a sacarificação de bagaço de cana-de-açúcar após pré-tratamentos ácido e alcalino foi comparada usando o extrato enzimático do fungo fitopatógeno Chrysoporthe cubensis e três coquetéis comerciais. Para o bagaço de cana utilizado neste estudo, o pré-tratamento alcalino promoveu os melhores rendimentos de sacarificação sendo o extrato do fungo C. Cubensis o responsável pela maior liberação de glicose e xilose quando comparado às misturas enzimáticas comerciais. Além disso, o extrato de C. cubensis produziu maiores valores de atividade específica comparados aos dos coquetéis comerciais. No terceiro capítulo, o potencial genômico de fungos candidatos foi avaliado e as enzimas mais interessantes para a hidrólise de bagaço de cana-de-açúcar foram expressas em Aspergillus vadensis. Nove enzimas de três fungos diferentes, Aspergillus terreus, Nectria haematoccoca e Phaeosphaeria nodorum, foram viiclonadas e expressas por sistema heterólogo e representam uma nova possiblidade para a melhor degradação do bagaço de cana. Dentre estas enzimas, quatro - xilosidases foram bioquimicamente caracterizadas e apresentaram atividade máxima em valores de pH 4,5-5,0 e em temperaturas 55-60°C. No quarto capítulo, duas xilanases de Aspergillus nidulans previamente clonadas em Pichia pastoris, aqui denominadas Xyn1818 e Xyn3613, foram expressas, purificadas e caracterizadas. Xyn1818 apresentou ótima atividade em pH 7.5 e à 60°C enquanto Xyn3613 alcançou máxima atividade em pH 6.0 e à 50°C. Xyn1818 apresentou-se bastante termoestável à 50°C mantendo 50% de sua atividade original após 49 horas de incubação nesta temperatura. Xyn1818 apresentou maior atividade contra arabinoxilana de trigo enquanto o melhor substrato para Xyn3613 foi xilana beechwood. Testes de sacarificação mostraram que os coquetéis comerciais liberaram mais açúcares (glicose e xilose) quando suplementados com as xilanases Xyn1818 e Xyn3613 de A. nidulans. Finalmente, no quinto capítulo, os fungos Aspergillus niger e Trichoderma reesei foram avaliados quanto à produção de enzimas após crescimento em do e bagaço de cana-de-açúcar. Os fungos produziram diferentes tipos de enzimas (hemi)celulolíticas, o que foi refletido pelo forte efeito sinergístico na liberação de açúcares durante a sacarificação dos substratos utilizando o conjunto de enzimas dos dois microorganismos. Foi constatado que a remoção de monossacarídeos do meio de produção de enzimas é muito importante quando combinações de enzimas de T. reesei and A. niger são utilizadas para aprimorar a hidrólise de biomassas.
Second generation ethanol production has great potential to be a sustainable reality, especially in Brazil due to the large amount of available sugarcane bagasse. Pretreatment methods and biomass hydrolysis continue to be the bottlenecks of the overall process, mainly this second step since the enzymes present high costs. Therefore, efforts have been taken to make the process more cost-effective with regards to the discovery of more effective enzymes. New sources of enzymes are continuously encountered and several strategies of enzyme prospection and production have been studied. One strategy used in the search for new and/or more efficient enzymes is comparative genomic analysis of different microorganisms which allows for the screening of several candidates of interest in a short period of time. Moreover, plant-degrading enzymes can be produced by fungi grown on abundantly available low-cost plant biomass. This work was divided in five chapters being the first chapter a current review about second generation ethanol production focused mainly on the saccharification step. Several strategies of enzyme prospection and production were discussed and detailed. In the second chapter, saccharification of acid- and alkali-pretreated sugarcane bagasse was compared using the enzymatic extract from the pathogen fungus Chrysoporthe cubensis and three commercial enzymatic mixtures. For the sugarcane bagasse studied in this work, the alkaline pretreatment promoted the best saccharification yields, where the C. cubensis extract was responsible for the higher release of glucose and xylose when compared to the commercial enzymatic mixtures Furthermore, the C. cubensis extract was able to produce high specific enzyme activities when compared to the commercial cocktails. In the third chapter, the genomic potential of the candidate fungi was evaluated and the most interesting enzymes for sugarcane bagasse hydrolysis were expressed in Aspergillus vadensis. Nine enzymes from three different fungi, Aspergillus terreus, Nectria haematoccoca and Phaeosphaeria nodorum, were successfully cloned and expressed by heterologous system and these enzymes represent a possibility for a better degradation of sugarcane bagasse. -xylosidases were biochemicallycharacterized and showed maxima activity in the pH range 4.5-5.0 and at temperatures of 55-60°C. In the fourth chapter, two xylanases from Aspergillus nidulans previously cloned in Pichia pastoris, here nominated as Xyn1818 and Xyn3613, were expressed, purified and characterized. The optima pH and temperature for Xyn1818 were 7.5 and 60°C while Xyn3613 achieved maximal activity at pH 6.0 and 50°C. Xyn1818 showed to be very thermostable, maintaining 50% of its original activity after 49 hours when incubated at 50°C. Xyn1818 presented higher activity against wheat arabinoxylan while Xyn3613 had the best activity against xylan from beechwood. Saccharification results showed that the commercial enzymatic cocktails were able to release more sugars (glucose and xylose) after supplementation with the xylanases Xyn1818 and Xyn3613 from A. nidulans. Finally, in the fifth chapter, Aspergillus niger and Trichoderma reesei were substrates: wheat straw and sugarcane bagasse. The fungi produced different sets of (hemi-)cellulolytic enzymes which was reflected in an overall strong synergistic effect in releasing sugars during saccharification using the enzyme blends from both fungi. It was observed that removing monosaccharides from the enzyme production media is very important when T. reesei and A. niger enzyme blends are combined to improve plant biomass saccharification.
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Jones, Rudy. "Enhanced ethanol production: In-situ ethanol extraction using selective adsorption." Thesis, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/22658.
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In order to produce ethanol derived from lignocellulosic feeds at a cost that is competitive with current gasoline prices, the fermentation process, converting sugars to produce ethanol and the subsequent purification steps, must be enhanced. Due to their comparatively lower costs, the widespread availability across a range of climates, and their status as a dedicated energy crop, lignocellulosic biomass feeds are ideal raw materials that can be used to produce domestic fuels to partly displace our dependence on non-renewable sources. Currently, a major drawback of the technology is the relatively low ethanol tolerance of the micro-organisms used to ferment xylose and glucose.
To alleviate the ethanol inhibition of Escherichia coli KO11 (ATCC 55124) during fermentation, online ethanol sequestration was achieved through the implementation of an externally located packed bed adsorber for the purpose of on-line ethanol removal (using F-600 activated carbon).
By removing ethanol from the broth during the fermentation, inhibition due to the presence of ethanol could be alleviated, enhancing the substrate utilization and fermentation rate and the ethanol production of the fermentation.
This study details a comprehensive adsorbent screening to identify ethanol selective materials, modelling of multi-component adsorption systems, and the design, implementation and modelling of a fermentation unit coupled with an externally located packed bed adsorber.
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Dodo, Charlie Marembu. "Ethanol production from lignocellulosic sugarcane leaves and tops." Thesis, University of Fort Hare, 2014. http://hdl.handle.net/10353/d1019839.
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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.
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Ricciotti, Federica. "Plasma based pretreatments of lignocellulosic biomass for Biogas and Bioethanol production." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018.
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The aim of this project provides the use of a lignocellulosic biomass microbubble reactor in order to analyse the pre-treatment of cellulose and maize for, respectively, Bioethanol and Biogas production. Because of lignin recalcitrance, dielectric barrier discharge plasma is used to improve the solubility and accessibility of these feedstock. The novel reactor combined with this plasma source generates highly oxidative species (O3, H2O2, and OH radicals) close to the gas-liquid interface. The cellulose has been treated under different conditions such as treatment time (30 min, 60 min, 90 min and 120 min) and pH buffer solution (pH 3, pH 7 and pH 9). The maize biomass has been reacted under 5 different conditions (Control sludge, Untreated raw maize, Plasma treated washed maize, Plasma treated unwashed maize, Bubble treated unwashed maize). The optimal operating condition, for cellulose biomass, that produced the highest glucose concentration results with pH 3 and with 30 min treatments. On the other hand, maize samples treated with plasma, both washed and unwashed, generate more biogas than bubble treatment, control sludge or untreated raw maize.
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Zhu, Li. "Fundamental study of structural features affecting enzymatic hydrolysis of lignocellulosic biomass." Texas A&M University, 2005. http://hdl.handle.net/1969.1/4314.
Full textAbstract:
Lignocellulose is a promising and valuable alternative energy source. Native
lignocellulosic biomass has limited accessibility to cellulase enzyme due to structural
features; therefore, pretreatment is an essential prerequisite to make biomass accessible
and reactive by altering its structural features.
The effects of substrate concentration, addition of cellobiase, enzyme loading,
and structural features on biomass digestibility were explored. The addition of
supplemental cellobiase to the enzyme complex greatly increased the initial rate and
ultimate extent of biomass hydrolysis by converting the strong inhibitor, cellobiose, to
glucose. A low substrate concentration (10 g/L) was employed to prevent end-product
inhibition by cellobiose and glucose. The rate and extent of biomass hydrolysis
significantly depend on enzyme loading and structural features resulting from
pretreatment, thus the hydrolysis and pretreatment processes are intimately coupled
because of structural features.
Model lignocelluloses with various structural features were hydrolyzed with a
variety of cellulase loadings for 1, 6, and 72 h. Glucan, xylan, and total sugar
conversions at 1, 6, and 72 h were linearly proportional to the logarithm of cellulase
loadings from approximately 10% to 90% conversion, indicating that the simplified
HCH-1 model is valid for predicting lignocellulose digestibility. Carbohydrate
conversions at a given time versus the natural logarithm of cellulase loadings were
plotted to obtain the slopes and intercepts which were correlated to structural features (lignin content, acetyl content, cellulose crystallinity, and carbohydrate content) by both
parametric and nonparametric regression models.
The predictive ability of the models was evaluated by a variety of biomass (corn
stover, bagasse, and rice straw) treated with lime, dilute acid, ammonia fiber explosion
(AFEX), and aqueous ammonia. The measured slopes, intercepts, and carbohydrate
conversions at 1, 6, and 72 h were compared to the values predicted by the parametric
and nonparametric models. The smaller mean square error (MSE) in the parametric
models indicates more satisfactorily predictive ability than the nonparametric models.
The agreement between the measured and predicted values shows that lignin content,
acetyl content, and cellulose crystallinity are key factors that determine biomass
digestibility, and that biomass digestibility can be predicted over a wide range of
cellulase loadings using the simplified HCH-1 model.
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Gourlay, Keith Ian. "The role of amorphogenesis in the enzymatic deconstruction of lignocellulosic biomass." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/50850.
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Agricultural and forestry-derived fibres can be converted into fuels and chemicals via a biorefinery. However, the densely-packed fibrillar architecture of lignocellulosic biomass makes the cellulose inherently inaccessible to the enzymes involved in this bioconversion process. This limits the efficiency of enzymatic deconstruction and necessitates relatively high enzyme/protein loadings, which decreases the economic viability of the overall process.
It has previously been suggested that the rate-limiting step of cellulose hydrolysis is not the depolymerisation of the carbohydrate chains, but rather the rate at which the enzymes can gain access to the cellulose buried within the biomass. Recently, several proteins such as the Expansins, Swollenin and Loosenin have been shown to disrupt the cellulosic structure without directly depolymerizing the carbohydrates. This protein-induced “amorphogenesis” is thought to occur as a delamination, splitting, peeling, swelling, or decrystallizing of the biomass, thereby enhancing accessibility of the entrenched carbohydrates to the depolymerizing enzymes. However, a key challenge when studying these amorphogenesis-inducing proteins involves quantifying their disruptive effects. While depolymerizing enzymes can be readily quantified by measuring the amount of liberated soluble sugars, amorphogenesis-inducing proteins are thought to promote a variety of disruptive effects without releasing soluble products.
As the undefined nature of the amorphogenesis end product makes quantification challenging, one of the initial goals of the work was to refine/develop techniques to better quantify amorphogenesis. Two distinct carbohydrate binding modules (CBMs), one of which preferentially binds to crystalline cellulose and the other to amorphous cellulose were used to track changes in cellulose accessibility and surface morphology. When various substrates were treated with the amorphogenesis-inducing protein, Swollenin, CBM adsorption revealed that Swollenin promoted the dispersal and disruption of the more amorphous regions of biomass, increasing the access of the depolymerizing enzymes to the cellulose component. Subsequent work involving the fluorescent tagging of these CBMs and confocal microscopy further suggested that Swollenin was targeting the less-ordered regions of the cellulosic substrate. When Swollenin was assessed for its ability to disrupt an industrially-relevant substrate, steam pretreated corn stover, it primarily targeted amorphous regions where it synergised strongly with xylanases (~300%), promoting the release of hemicellulosic oligomers.Forestry, Faculty of
Graduate
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Rengel, Ana. "Study of Lignocellulosic Biomass Pyrolysis : State of the Art and Modelling." Thesis, KTH, Industriell ekologi, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-32757.
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Fast pyrolysis is a technology that is emerging as an alternative to transform organic and fossil materials into a new form of energy, mainly the so-called bio-oil. Until nowadays, examples of raw materials that have been experimented are wood and forest residues, bagasses as well as straw and agro-residues. After pyrolysis conversion, the final products are solids (char), liquids (tar) and gases. Through several experimental studies, authors have been found that there are parameters which influence final products quality. They are feedstock composition, type of reactor, final temperature, heating rate, sweeping gas flow rate, vapors residence time and particle sizes. In feedstock composition, the quantities of cellulose, hemicellulose, lignin, ash and water have received special attention. Usually, feedstock is pre-heated to reduce water content and grinded to particle sizes smaller than 1.8 mm; before it enters into the reactor. Among different reactor configurations, the most common is the fluidized bed reactor at industrial and laboratory scale. Generally, the reactor is designed and constructed for laboratory experiments. It has been reported that final temperature and heating rate greatly affect final products. Authors coincide that higher temperature increases overall conversion and liquid yields present a maximum. However, for higher heating rates there is a controversy in liquid yields. During pyrolysis, an inert gas is used to sweep the gases and to diminish vapors residence time. It is believed that at longer vapors residence time, secondary reactions between the gases and the char may occur. The most common sweeping gas is nitrogen followed by helium and argon. In order to study experimentally these parameters, a test bench will be built at the “Center for Energy and Processes” at the Ecole des Mines de Paris. Wood samples will be used as a feedstock and will pyrolized under nitrogen in a horizontal quartz reactor. The sample will be heated by radiation, emitted at a constant flux by a radiant. During the experiments, temperature, heating rate, sweeping gas, and particle sizes will be varied in order to observe their effect in final yields. Based on the kinetics equations proposed by Radmanesh et al., a computational model was created with the experimental conditions. The sample was modeled as a set of five layers, considering each one as a porous media. For each layer, a heat transfer coefficient was calculated as the sum of conduction and radiation coefficients. The results illustrate the evolution of temperature, heating rates, total gases, condensable and noncondensable gases at different radiations and particle sizes. They show agreement with the results obtained by Radmanesh et al. as well with other experimental studies. In addition, evolution of ellulose, hemicellulose and lignin were observed through the time and according to the layer temperature, demonstrating concordance with literature and previous studies.www.ima.kth.se
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João, Karen Andreína Godinho. "Pre-treatment of different types of lignocellulosic biomass using ionic liquids." Master's thesis, Faculdade de Ciências e Tecnologia, 2013. http://hdl.handle.net/10362/10386.
Full textAbstract:
Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau Mestre em BiotecnologiaThe pre-treatment of biomass by ionic liquid (IL) is a method opening new possibilities of biomass fractionation for further valorisation of low value feedstock. This work is dedicated to study on the pre-treatment and fractionation of different types of lignocellulosic biomass into its major constituent fractions (cellulose, hemicellulose and lignin), using ILs. The biomass tested was: wheat straw, sugarcane bagasse, rice straw and triticale. Initially, the optimised methods were development basing on two methodologies described in the literature. This method allows the separation into high purity carbohydrate-rich (cellulose and hemicellulose) and lignin-rich fractions and permits an efficient IL recovery. The possibility of IL reuse was confirmed, demonstrating the great potential of the established method. The pre-treatment of various biomasses confirms the versatility and efficiency of the optimised methodology since not only the complete macroscopic dissolution of each biomass was achieved but also the fractionation process was successfully performed. Pre-treatment of sugarcane bagasse and triticale allowed to obtained cellulose samples rich in carbohydrate up to 90 wt %. In order to verify the potential further applicability of the obtained carbohydrate-rich fractions, as well as to evaluate the pre-treatment efficiency, the cellulose-rich fraction resulting from 1-ethyl-3-methylimidazolium acetate ([emim][OAc]) pre-treatment was subjected to enzymatic hydrolysis. Results showed a very high digestibility of the cellulose-rich samples and confirmed a high glucose yield for the optimised pre-treatment methodology. The samples obtained after the pre-treatment with ILs were qualitatively and quantitatively analysed by Fourier Transform Infrared Spectroscopy (FTIR). After the pre-treatment, the purity of the recovered ILs was evaluated through Nuclear Magnetic Resonance spectroscopy (NMR). The enzymatic hydrolysis results were analysed by High-Performance Liquid Chromatography(HPLC).
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Avery, Greg M. "A Life Cycle Assessment of Ionic Liquid Pretreatment for Lignocellulosic Biomass." University of Toledo / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1481273168926691.
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Giuliano, Aristide. "Process optimization of a lignocellulosic multi-product biorefinery." Doctoral thesis, Universita degli studi di Salerno, 2016. http://hdl.handle.net/10556/2364.
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2014 - 2015A methodology to reduce the complexity of the process optimization was applied to multiproduct biorefinery fed by lignocellulosic biomass. A process superstructure was built to consider alternative process pathways to levulinic acid, succinic acid and ethanol. A Mixed Integer Non-Linear Problem was obtained and transformed in a Mixed Integer Linear Problem by means of a discretization procedure of the non-linear variables. Rigorous design methods accounting for complete kinetics schemes for hydrolysis and fermentation reactors for the production of levulinic acid, succinic acid and ethanol were included in a biorefinery superstructure optimization. A discretization method was applied to obtain a MILP approximation of the resulting MINLP master problem. The optimal flowsheet of a biorefinery with hardwood feedstock, obtained by maximizing the Net Present Value, yields comparable biomass allocation to levulinic acid and succinic acid (more than 40% each) and the its balance to ethanol. A sensitivity analysis highlighted that the optimal flowsheet and the relevant technical and economic performances are significantly dependent on the economic scenario (chemical products selling price, discount rate) and on the plant scale. Finally, process optimization achieved by maximizing two different economic objective functions, Net Present Value and Internal Rate of Return, provided different optimal flowsheets and biomass allocation to chemical products. The effect of the change of the biomass type and composition on the plant was also considered. Results highlight that the composition of the biomass feedstock in terms of cellulose, hemicellulose and lignin has a significant effect on the biomass allocation to the three product production processes and on the relevant optimal flowsheet. Case studies with a combined use of different seasonal biomass types during the year were also studied to provide a methodology to find the optimal biorefinery flowsheet in real scenarios. In the season based scenario studied, product yield distribution and overall productivity of the plant varies during the different periods provided a constant biomass feed rate. [edited by Author]
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Fonoll, Almansa Xavier. "Strategies to improve anaerobic digestion of wastes with especial attention to lignocellulosic substrates." Doctoral thesis, Universitat de Barcelona, 2015. http://hdl.handle.net/10803/379547.
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The energy demand increase and the generation of wastes is being the major problem regarding the next generation sustainability. Both problems can be corrected through the implementation of anaerobic digestion, a waste treatment technology able to produce electricity, heat and a fertilizer. The anaerobic co-digestion between two wastes with complementary characteristics has been widely studied to improve the methane production in anaerobic digesters. However, to increase the methane production from lignocelulosics substrates is still one of the main challenges of anaerobic digestion. Lignocelulosic components are a tridimensional structure between lignin, hemicellulose and cellulose, which bonds are extremely difficult to degrade by conventional anaerobic bacteria. Besides, those components can be found in a wide range of substrates such as municipal solid wastes, agro-wastes and energy crops.
In the following thesis, the increase of the economic viability of anaerobic digestion plants treating lignocelulosic materials has been studied.
Initially, the transitory state while the co-substrate was changed in the anaerobic co-digestion between sewage sludge and fruit waste was studied. The stability of the reactors was not drastically affected when the co-substrate was changed, but, the use of a co-substrate with a high concentration of fibers did not improve the methane production too much. Secondly, in order to consider the valorization of lignocellulosic components through the production of by-products, the effect of these components on the municipal solid wastes anaerobic digestion performance was evaluated. When the paper waste was removed, the biodegradability of the feedstock increased allowing the specific methane production to increase. Nevertheless, the digester was more fragile against instabilities and the digestate quality decreased if short retention times are applied. Next, low-temperature and ultrasounds pretreatments, strategies that have not been used too much for the degradation of lignocellulosic components, were studied to increase the methane production during the anaerobic co-digestion of barley waste and pig manure. Low-temperature and ultrasound pretreatment increased the methane production in a 27 and 12% respectively but only the first one had a positive energy balance. Finally, rumen, a waste from the slaughterhouse industry was used as inoculum and as co-substrate to bring hydrolytic bacteria able to improve the degradation of Napier grass. The results showed that, when rumen is used as inoculum it need to be mixed with an inoculum with high buffer capacity and a co-substrate with alkalinity need to be used to avoid long start-up periods. The methane production only increased at the beginning and in a long-term, the microbial community was governed by the substrate and not by the rumen. However, rumen did not increase the methane production when it was used as a co-substrate because the digester conditions were not optimal for the activity of hydrolytic bacteria. All the experiments were carried out in the laboratory and the conclusions are considered a progress for the energy production through the use of lignocellulosic substrates.El incremento de la demanda energética y la consecuente generación de residuos ponen en peligro la sostenibilidad del futuro. Es por eso que la digestión anaeróbica resulta ser una solución factible para mitigar el problema ya que se puede generar electricidad, calor y fertilizante a partir de los residuos orgánicos. El incremento de la producción de metano se consiguió a partir de la co-digestión de residuos con características complementarias. Aun así, no siempre se consigue extraer todo el potencial metanogénico de los residuos, especialmente, en el caso de los sustratos ligno-celulósicos. Los compuestos ligno¬celulósicos son estructuras complejos entre la lignina, la hemicelulosa y la celulosa con enlaces resistentes a la degradación microbiana que se encuentran en los residuos agro-industriales, los residuos municipales y los cultivos energéticos. En la tesis, se ha buscado aumentar la viabilidad económica de las plantas de digestión anaeróbica que tratan residuos con componentes ligno-celulósicos. Se usaron distintas nuevas estrategias para aumentar la degradabilidad de la materia ligno-celulósica como los pretratamientos térmicos de baja temperatura y de ultrasonidos y la integración del rumen, un residuo de la industria cárnica, para aportar bacterias hidrolíticas. Para valorar la opción de separar estos componentes para la formación de sub-productos, se estudió su efecto sobre el rendimiento del digestor en términos de estabilidad, producción de metano y calidad del digerido para así poder implementar la producción se sub-productos. Los estudios realizados en esta tesis doctoral se llevaron a cabo a escala de laboratorio y las conclusiones han supuesto un avance para el aprovechamiento energético de los residuos ligno-celulósicos en el futuro.
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Narayana, Swamy Naveen. "Supercritical Carbon Dioxide Pretreatment of Various Lignocellulosic Biomasses." Ohio University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1269524607.
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Jackowiak, David. "Prétraitement de biomasses lignocellulosiques par microondes pour l'amélioration du procédé de biométhanisation." Compiègne, 2011. http://www.theses.fr/2011COMP1921.
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La structure de la biomasse lignocellulosique ainsi que sa composition par la présence de lignine sont connues comme étant des facteurs limitant la digestion anaérobie. En effet, la lignine forme une barrière physique et limite l’adhésion et l’activité des enzymes. C’est pourquoi cette thèse vise à étudier les effets d’un chauffage de la matière lignocellulosique par traitement microonde, sur la solubilisation de la matière via la DCO soluble, et sur la digestibilité anaérobie via des BMP. Les études expérimentales ont été menées sur de la paille de blé et sur le panic érigé, et ont révélé que leurs prétraitements par microondes menaient à une solubilisation accrue de la matière et une amélioration de leur digestibilité anaérobie. Les paramètres optimaux de prétraitements déterminés sont une température de consigne d’environ 150°C qu’il est préférable d’atteindre rapidement et sans pour autant maintenir cette valeur de température de consigne. Une augmentation de température au-delà de 150°C induit une augmentation de la solubilisation de la matière mais diminue la biodégradabilité de celle-ci. Ce travail a également étudié la balance énergétique. L’énergie calculée issue de la différence de production en méthane entre un échantillon traité et non traité ne compense pas l’énergie consommée par le prétraitement par microonde pour les appareils utilisés. Il apparaît donc nécessaire d’étudier le développement d’un appareil industriel adaptéThe structure and composition of lignocellulosic biomass are known to be critical points to use this material in anaerobic digestion. Indeed, the presence of lignin forms a physical barrier and induces a non-productive adsorption and activity of enzymes. Therefore, this thesis aims at to study the effects of microwave heating of lignocellulosic material, especially on matter solubilisation through soluble COD, and on anaerobic digestion through BMP assays. Experimental studies were carried out on wheat straw and switchgrass, and revealed that their microwave pretreatments led to increase of matter solubilisation and an improvement of their anaerobic digestibility. The best conditions found are the highest heating rate for a final temperature 150°C without any holding time. A temperature beyond 150°C induces an increase of matter solubilisation but decreases the biodegradability of lignocellulosic material. This work studied also the energy balance. The energy calculated from the difference of methane production between treated and untreated sample does not compensate the energy consumed by the microwave pretreatment, at least with the microwave devices used. It therefore appears necessary to study the development of adapted industrial apparatus
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Abels, Christian [Verfasser]. "Membrane separations in ionic liquid assisted processing of lignocellulosic biomass / Christian Abels." Aachen : Hochschulbibliothek der Rheinisch-Westfälischen Technischen Hochschule Aachen, 2014. http://d-nb.info/1059535912/34.
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Berg, Heidi Odegård. "Comparison of conversion pathways for lignocellulosic biomass to biofuel in Mid-Norway." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for energi- og prosessteknikk, 2013. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-22375.
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This work investigates one biochemical and one thermochemical biomass-to-liquid biofuel conversion pathway in terms of lignocellulose conversion to liquid Fischer-Tropsch diesel. The focus has been on comparing the two conversion pathways in terms of identifying their energy flows and respective feed to fuel ratios. The conversion pathways investigated comprise two-stage conversion sequences including biomass-to-gas conversion and gas-to-liquid conversion, exerted by anaerobic digestion or gasification followed by Fischer-Tropsch synthesis. A systematic documentation of available technologies regarding the two conversion pathways is performed by literature study. The pathways are modeled in Aspen Plus supplied with FORTRAN declarations. Mass flows and composition for the two pathways are collected from simulations and energy flows are identified by heating value and energy balance calculations. The energy flows are presented graphically and by ESankey-diagrams, and the resulting energy utilities and feed to fuel ratios are presented graphically and in tabular form.The key finding is that for the application to Fischer-Tropsch processes, the biochemical conversion pathway is less energy effective in terms of gas-to-liquid conversion. This result is observed both in terms of energy utility for the pathway and might indicate that biochemical pathways are more energy consuming than conventional thermochemical gas-to-liquid conversion. However, results on feed to fuel ratio indicate that the biochemical conversion of lignocellulose to Fischer-Tropsch diesel is competitive when compared to thermochemical conversion.
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Yan, Lishi. "Kinetic characterization of hot water and dilute acid pretreatment of lignocellulosic biomass." Thesis, Washington State University, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3628899.
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Acidic aqueous-phase pretreatment is a promising approach that has been directed at maximizing intermediates yields (e.g. sugars, sugar degradation products, and lignin) from biomass for fuel and chemical production. This dissertation explores the kinetic fundamentals of biomass hydrolysis in acidic aqueous-phase with different catalysts (e.g. sulfuric acid, metal chlorides), operating conditions (e.g. temperature, time pressure), and equipment configurations (e.g. batch, flowthough).
The kinetic analysis revealed that crystalline cellulose is insusceptible to hydrolysis compared with agarose at low temperature (e.g.140 °C), while it decomposed rapidly at elevated temperature (e.g. 220 °C). Higher temperature with reduced time was desirable for glucose production whereas lower temperature with prolonged time was preferred for xylose generation. In acidic conditions, furfural and levulinic acid were stable whereas 5-hydroxymethylfurfural was susceptible to decomposition with high rate constant. MgCl2 can promote the cleavage of C-O-C bond in polysaccharides (e.g. agarose) and enhance the subsequent dehydration reaction to 5-hydroxymethylfurfural. Unlike transition metal chlorides and H2SO4, MgCl2 has little ability to induce retro aldol and rehydration reactions to generate byproducts like lactic acid and levulinic acid. Mg2+ possessing hgiher activity than other alkali and alkaline earth metal chlorides (Na+ and Ca2+) resulted in 40.7% yield and 49.1% selectivity of 5-hydroxymethylfurfural.
Dissolution of biomass was significantly enhance using acidic hot water flowthrough pretreatment at 200—280°C. Significant cellulose removal accompanied with the transformation of cellulose I to cellulose II and amorphous cellulose were observed when temperature was above 240 °C for water-only and 220 °C for dilute acid. Approximately100% of the xylan and ∼90% of the cellulose were solubilized and recovered. Up to 15% of the lignin was solubilized, while the remaining lignin was insoluble. Over 90% sugar yields were obtained from pretreated whole slurries using less than 10 FPU/g cellulase plus hemicellulase enzyme.
A kinetic model was developed to depict the biomass degradation in flowthrough system. This model predicted the sugar generation more precisely than the conventional homogeneous first-order reaction models. Mass transfer limitations were minimized using 4mm biomass particle sizes with 4g biomass loading at 25mL/min flow rate, produced hydrolyzate slurries with 13g/L potential sugar concentrations.
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Godoy, Jayfred Gaham Villegas. "Sorghum improvement as biofuel feedstock: juice yield, sugar content and lignocellulosic biomass." Thesis, Kansas State University, 2011. http://hdl.handle.net/2097/9254.
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Master of ScienceDepartment of Agronomy
Tesfaye Tesso
Sorghum [Sorghum bicolor (L.) Moench] is listed as one of the potential feedstock sources for biofuel production. While sorghum grain can be fermented into ethanol in a similar way as maize, the greatest potential of the crop is based on its massive biomass and sugar rich juices. Thus development of the crop as alternative energy source requires improvement of these traits. The objectives of this study were (1) to determine the mode of inheritance of traits related to ethanol production and identify suitable genetic sources for use in breeding programs, and (2) to evaluate the potential of low lignin mutations for biomass feedstock production and assess biotic stress risks associated with deployment of the mutations. The study consisted of three related experiments: (i) estimating the combining ability of selected sweet and high biomass sorghum genotypes for biofuel traits and resistance to stalk lodging, (ii) determine the impact of brown mid-rib mutations on biofuel production and their reaction to infection by Macrophomina phaseolina and Fusarium thapsinum, and (iii) assess the reaction of low lignin mutants to green bug feeding. In the first experiment six sorghum genotypes of variable characteristics (PI193073, PI257602, PI185672, PI195754, SC382 and SC373) were crossed to three standard seed parent lines ATx3042, ATx623 and ATx399. The resulting hybrids and the parents were evaluated at four locations, three replications during 2009 and 2010 seasons. Data were collected on phenology, plant height, juice yield, °brix score and biomass production. In the second experiment, two brown mid-rib mutations (bmr6 and bmr12) and their normal versions were studied in four forage sorghum backgrounds (Atlas, Early Hegari, Kansas Collier and Rox Orange). The experiment was planted in four replications and at 14 d after flowering five plants in a plot were artificially infected with F. thapsinum and another five with M. phaseolina. The plants were harvested and rated for disease severity (lesion length and nodes crossed). Another five normal plants in each plot were harvested and used to determine biofuel traits (juice yield, ºbrix score and biomass). In the third experiment, a subset of entries evaluated in experiment II and three tolerant and susceptible checks were tested for greenbug feeding damage. Biotype K greenbug colony was inoculated to each genotype using double sticky foam cages. Feeding damage was assessed as percent chlorophyll loss using SPAD meter. There was significant general combining ability (GCA) effect among the male entries for juice yield, stem obrix and biomass production indicating that these traits are controlled by additive genes. Lines PI257602 and PI185672 in particular, had the highest GCA for all the traits and should serve as excellent breeding materials. There was no significant difference among the bmr mutants and between the bmr and normal genotypes for both stalk rot and greenbug damage. In conclusion, juice yield, °brix and biomass are largely controlled by additive genes and hence are amenable to genetic manipulation. The bmr mutations despite their impact on lignin content do not increase risk of attack by stalk rot pathogens and greenbugs and thus can be deployed for biofuel production without incurring losses to these factors.
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Tyufekchiev, Maksim V. "Reaction Engineering Implications of Using Water for the Conversion of Lignocellulosic Biomass." Digital WPI, 2020. https://digitalcommons.wpi.edu/etd-dissertations/619.
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Conversion of lignocellulosic biomass via hydrolysis of cellulose to simple sugars has failed to achieve economic competitiveness to produce renewable fuels and chemicals partly due to the inherent recalcitrance of the substrate and partly due to the use of non-recyclable catalysts. Solid acids have been proposed for cellulose hydrolysis as a recyclable alternative to enzymes and homogeneous acids. However, their catalytic mechanism has not been elucidated partly due to incomplete structural characterization. We focused on elucidating the structure of chloromethyl polystyrene based catalysts which exhibit remarkable activity towards hydrolyzing cellulose. By carrying out spatially resolved analysis of CMP-SO3H-0.3, a catalyst decorated with benzyl chloride and benzyl sulfonic acid groups, we discovered that the external surface of the catalyst is devoid of any chloride groups, which were hypothesized to interact with cellulose. Despite apparent greater reactivity than sulfonated-only catalysts, we found the CMP-SO3H-0.3 reacts with water at the reaction conditions used for cellulose hydrolysis, resulting in leaching of homogeneous hydrochloric acid, which in turn is responsible for the observed cellulose hydrolysis. Building on these results we investigated whether catalysts from various structural classes are stable in the hydrothermal environment or leach homogeneous acid. Surprisingly, we discovered that materials commonly used for cellulose hydrolysis are hydrothermally unstable and the leached homogeneous acid they produced was responsible for their apparent catalytic activity. On the other hand, hydrothermally stable materials did not exhibit greater hydrolysis activity than water. Cellulose crystallinity has been theorized for decades as a structural parameter determining the reactivity of cellulose, which motivated decrystallization pretreatment processes. However, water-induced recrystallization had not been accounted for in hydrolysis models, albeit being a well-documented phenomenon, and all hydrolysis processes use water as a reaction medium. By carrying out detailed structure-reactivity analysis we concluded that decrystallized cellulose undergoes a rapid transformation to an active crystalline cellulose, characterized by allomorphs I and II and greater content of surface polymer chains. Water-induced recrystallization reduced the reactivity of cellulose and prevented conversion of highly reactive amorphous regions. To circumvent the recrystallization pathway, we used ethanolysis as a means for rapid and selective depolymerization of amorphous cellulose. Ethanolysis of ball-milled cellulose for 30 minutes at 410 K resulted in 38% conversion, while hydrolysis at the same conditions in only 15%. Scission-relaxation caused recrystallization and limited conversion via ethanolysis. By using co-solvents capable of swelling cellulose, we were able to increase cellulose conversion to 48%. The results presented in those studies can guide future development of catalysts and depolymerization processes that circumvent the inhibiting effects caused by the use of water.