Tesis: "Lignocellulosic biomass"

1

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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3

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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4

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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5

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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6

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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7

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 Ambiental
The 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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8

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 Philosophy
Department 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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9

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 Biotecnologia
O 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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12

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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13

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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14

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 / UL
The 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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15

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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16

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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17

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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18

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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19

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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20

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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21

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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22

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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23

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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24

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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25

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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26

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.

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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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27

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
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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.
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29

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.

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Dissertação apresentada na Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa para obtenção do grau Mestre em Biotecnologia
The 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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30

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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31

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 - 2015
A 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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32

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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33

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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34

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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35

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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36

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 Science
Department 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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37

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.

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38

Marriott, Poppy. "Identifying novel genes to improve lignocellulosic biomass as a feedstock for bioethanol". Thesis, University of York, 2014. http://etheses.whiterose.ac.uk/7156/.

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The dwindling reserves of fossil fuels, coupled with the environmental consequences of burning these fuels, mean that a more sustainable alternative is required. Bioethanol produced from lignocellulosic biomass is an attractive candidate for the replacement of liquid transportation fuels. Lignocellulosic biomass is composed of plant cell walls, which are extremely resistant to digestion. Converting this biomass to fermentable sugars for bioethanol production therefore requires energetic pretreatment and expensive enzyme applications. To make lignocellulosic bioethanol a commercial reality, the conversion efficiency needs to be improved and one approach of doing so is to produce crops that are more susceptible to hydrolysis. To this end, this study used a forward genetic approach with the objective of identifying genes that affect the digestibility of plant biomass. A chemically mutagenised population of the model grass Brachypodium distachyon was screened for improved saccharification with industrial cellulases. This revealed 12 mutant lines with heritable increases in saccharification. Characterisation of these 12 mutants revealed a range of different alterations in cell wall composition. Interestingly, a number of the mutant lines showed no change in lignin content, which is thought to be the major contributor to cell wall recalcitrance. These results show that saccharification can be significantly improved through a number of distinct modifications of the cell wall, giving the potential for combining more than one of these modifications in biofuel crops to obtain even higher ethanol yields. Furthermore, the mutations seem to have little effect on plant growth, development or stem strength, important traits for crop field performance. Candidate causal mutations of three of the high saccharification mutants have been identified and characterisation of the mutated genes has begun. In the long term, this will enable subsequent examination of orthologous genes in the relevant cereal and grass crops used for biofuel production.

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39

Melloni, Mattia <1989&gt. "From Lignocellulosic Biomass to Rare Sugars: Hydrolisis and Isomerization with Heterogeneous Catalysts". Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amsdottorato.unibo.it/8056/1/Melloni_Mattia_tesi.pdf.

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The PhD project presented in this thesis focused on two research topics turned to contribute to the development of a modern model of production, that is able to reduce the environmental impact of the chemical industry. For this purpose, preparation and characterization of heterogeneous catalysts for the transformation of renewable raw materials into valuable chemicals has been studied. The first part of the work concerned the conversion of lignocellulosic biomass, the most abundant renewable source presents on Earth, into monosaccharides and bio-building blocks, such as HMF, furfural and levulinic acid. Solid acid metal phosphate catalysts were synthetized for lignocellulose transformation; the catalytic behaviors shown by prepared metal phosphates were correlated to their physical-chemical properties: in particular, the role of acid features on the hydrolysis reaction has been studied. The synthesis of interesting industrial monosaccharides that cannot be obtained in appreciable amount from natural resources, called rare sugars, was the topic of the second part of the work. For this purpose, the rearrangement of glucose by the use of heterogeneous catalysts containing titanium was studied: especially, the influence of the different Ti species on products distribution has been investigated.

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40

Gogar, Ravikumar Leelamchand. "Economic Production of Furans from Lignocellulosic Sugars". University of Toledo / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1595977336480846.

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41

Mutengwe, Rudzani Ruth. "Isolation and characterisation of a xylanase producing isolate from straw-based compost". Thesis, University of the Western Cape, 2012. http://hdl.handle.net/11394/4495.

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>Magister Scientiae - MSc
Lignocellulosic biomass, a waste component of the agricultural industry, is a promising source for use in bioethanol production. Due to a complex structure, the synergistic action of lignocellulosic enzymes is required to achieve complete digestion to fermentable sugars. This study aimed to isolate, identify and characterise novel lignocellulase producing bacteria from thermophilic straw-based compost (71°C). Colonies with different morphological characteristics were isolated and screened for lignocellulosic activity. A facultative aerobic isolate RZ1 showed xylanase, cellulase and lipase/esterase activity. In addition to these activities, it was also able to produce proteases, catalases, amylases and gelatinases. RZ1 cells were motile, rod-shaped, Gram positive and endospore forming. The growth temperature of isolate RZ1 ranged from 25-55°C with optimal growth at 37°C. The 16S rRNA gene sequence was 99% identical to that of Bacillus subtilis strain MSB10. Based on the biochemical and physiological characteristics and 16S rRNA gene sequence, isolate RZ1 is considered a member of the species B. subtilis. A small insert genomic library with an average insert size of 5 kb was constructed and screened for lignocellulosic activity. An E.coli plasmid clone harbouring a 4.9 kb gDNA fragment tested positive for xylanase activity. The xyl R gene was identified with the aid of transposon mutagenesis and the deduced amino acid sequence showed 99% similarity to an endo-1-4-β-xylanase from B. pumilus. High levels of xylanases were produced when isolate RZ1 was cultured (37°C) with beechwood xylan as a carbon source. On the other hand, the production of xylanases was inhibited in the presence of xylose. Marked xylanase activity was measured in the presence of sugarcane bagasse, a natural lignocellulosic substrate. While active at 50°C, higher xylanase activity was detected at 37°C. Isolate RZ1 also produced accessory enzymes such as β-xylosidases and α-L-arabinofuranosidases, able to hydrolyse hemicellulose.

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42

Aghazadeh, Mahdieh. "The Effect of Different Lignocellulosic Biomass and Different Pretreatment Methods on Cellulase Activity". Fogler Library, University of Maine, 2011. http://www.library.umaine.edu/theses/pdf/AghazadehM2011.pdf.

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43

Dong, Jie. "Butanol Production from Lignocellulosic Biomass and Agriculture Residues by Acetone-Butanol-Ethanol Fermentation". The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1404312445.

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44

Costa, da Cruz Ana Rita. "Compositional and kinetic modeling of bio-oil from fast pyrolysis from lignocellulosic biomass". Thesis, Lyon, 2019. http://www.theses.fr/2019LYSE1006/document.

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La pyrolyse rapide est une des voies de conversion thermochimique qui permet la transformation de biomasse lignocellulosique en bio-huiles. Ces bio-huiles, différentes des coupes lourdes du pétrole ne peuvent pas être directement mélangés dans les procédés de valorisation. En effet, en raison de leur forte teneur en oxygène, les bio-huiles nécessitent une étape de pré-raffinage, telle que l’hydrotraitement, pour éliminer ces composants.L’objectif de ce travail est de comprendre la structure, la composition et la réactivité de la bio-huile grâce à la modélisation de données expérimentales. Pour comprendre leur structure et leur composition, des techniques de reconstruction moléculaire basées sur des données analytiques, ont été appliquées, générant un mélange synthétique, dont les propriétés correspondent à celles du mélange. Pour comprendre leur réactivité, l'hydrotraitement de molécules modèles a été étudié: gaïacol et furfural. Pour cela, un modèle déterministe et stochastique a été créé pour chacun d’eux. L’approche déterministe visait à récupérer une gamme de paramètres cinétiques, qui ont ensuite été affinés par l’approche stochastique créant un nouveau modèle. Cette approche a permis de générer un réseau de réactions en définissant et en utilisant un nombre limité de familles et règles des réactions. Finalement, le mélange synthétique a été utilisé dans la simulation stochastique de l’hydrotraitement de la bio-huile, étayée par la cinétique des molécules modèles.En conclusion, ce travail a permis de recréer la fraction légère de la bio-huile et de simuler leur l'hydrotraitement, via les paramètres cinétiques des composés modèles, qui prédisent de manière raisonnable les effluents de l'hydrotraitement de celles-ci, mais sont inadéquat pour le bio-huile
Fast pyrolysis is one of the thermochemical conversion routes that enable the transformation of solid lignocellulosic biomass into liquid bio-oils. These complex mixtures are different from oil fractions and cannot be directly integrated into existing petroleum upgrading facilities. Indeed, because of their high levels of oxygen compounds, bio-oils require a dedicated pre-refining step, such as hydrotreating, to remove these components.The aim of the present work is to understand the structure, composition and reactivity of bio-oil compounds through modeling of experimental data. To understand the structure and composition, molecular reconstruction techniques, based on analytical data, were applied generating a synthetic mixture, whose properties are consistent with the mixture properties. To understand the reactivity, the hydrotreating of two model molecules was studied: Guaiacol and Furfural. A deterministic and stochastic model were created for each compounds. The deterministic approach intended to retrieve a range of kinetic parameters, later on refined by the stochastic simulation approach into a new model. This approach generates an reaction network by defining and using a limited number of reaction classes and reaction rules. To consolidate the work, the synthetic mixture was used in the stochastic simulation of the hydrotreating of bio-oils, supported by the kinetics of the model compounds.In sum, the present work was able to recreate the light fraction of bio-oil and simulate the hydrotreating of bio-oils, via the kinetic parameters of model compounds, which can reasonably predict the effluents of the hydrotreating of these, but are unsuitable for bio-oil.Fast pyrolysis is one of the thermochemical conversion routes that enable the transformation of solid lignocellulosic biomass into liquid bio-oils. These complex mixtures are different from oil fractions and cannot be directly integrated into existing petroleum upgrading facilities. Indeed, because of their high levels of oxygen compounds, bio-oils require a dedicated pre-refining step, such as hydrotreating, to remove these components.The aim of the present work is to understand the structure, composition and reactivity of bio-oil compounds through modeling of experimental data. To understand the structure and composition, molecular reconstruction techniques, based on analytical data, were applied generating a synthetic mixture, whose properties are consistent with the mixture properties. To understand the reactivity, the hydrotreating of two model molecules was studied: Guaiacol and Furfural. A deterministic and stochastic model were created for each compounds. The deterministic approach intended to retrieve a range of kinetic parameters, later on refined by the stochastic simulation approach into a new model. This approach generates an reaction network by defining and using a limited number of reaction classes and reaction rules. To consolidate the work, the synthetic mixture was used in the stochastic simulation of the hydrotreating of bio-oils, supported by the kinetics of the model compounds.In sum, the present work was able to recreate the light fraction of bio-oil and simulate the hydrotreating of bio-oils, via the kinetic parameters of model compounds, which can reasonably predict the effluents of the hydrotreating of these, but are unsuitable for bio-oil

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45

Martinez, Aguilar Maricelly. "Production de biobutanol à partir de lignocellulose : un nouveau procédé thermochimique A simple process for the production of fuel additives using residual lignocellulosic biomass Production of fuel additives by direct conversion of softwood bark using a cheap metal salt Conversion of lignocellulosic biomass in biobutanol by a novel thermal process". Thesis, Ecole nationale des Mines d'Albi-Carmaux, 2020. http://www.theses.fr/2020EMAC0006.

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La demande d'énergie au cours des dernières années a augmenté et un grand pourcentage de l'énergie est dérivée des combustibles fossiles, mais l'utilisation de ces carburants a généré des émissions de CO2 et de la pollution environnementale. Pour ce problème, on a mené des recherches sur l'utilisation des énergies alternatives à partir de biomasse lignocellulosique pour produire des carburants qui réduisent les émissions de CO2. Le Canada est un pays avec une abondance de résidus lignocellulosiques qui sont une source pour la production de différents produits chimiques. La première partie de l’étude se concentre sur l’étude cinétique de la production du lévulinate de méthyle et de l’acide lévulinique à partir de la cellulose avec un catalyseur homogène (H2SO4). La deuxième partie porte sur la conversion de la cellulose en lévulinates (molécule plateforme) en utilisant un catalyseur homogène (H2SO4) et un catalyseur solide (Al2(SO4)3). La troisième partie se consacre sur l’étude de l’hydrolyse du lévulinate de méthyle en acide lévulinique en utilisant des catalyseurs à base de cuivre. Des techniques d’analyse tels que le SEM, XRD, TPX ont été utilisés pour étudier les catalyseurs supportés et comprendre leur effet sur la réaction. La quatrième partie du projet porte sur l’étude des résultats obtenus des différentes réactions réalisées pour la production du 2-butanol à partir de la biomasse lignocellulosique en passant par la production du lévulinate de méthyle et de l’acide lévulinique qui sont des molécules plateforme et potentiellement substitutes au biodiesel. Par la suite, l’acide lévulinique est décarboxylé en 2-butanone et le dernier est réduit en 2-butanol en utilisant des catalyseurs bifonctionnels (tels que le Ru / C et le Pt / C) en conditions douces. L’ensemble de ces travaux contribuent à la compréhension des réactions du nouveau procédé de production du butanol
In the last years, the energy demand has increased and a large pourcentage of this energy is obtained from fossil fuels, but the use of these fuels has generated CO2 emissions and environmental pollution. For this reason, this research was focused on the use of alternative energies from lignocellulosic biomass to produce renewal fuels decreasing CO2 gas emissions. Canada is a country with high quantities of lignocellulosic biomass which can represent a cheap source for the high value added molecules and fuels production. The first part of the study focuses on the kinetic study of the production of methyl levulinate and levulinic acid from cellulose with a homogeneous catalyst (H2SO4). The second part study the conversion of cellulose to levulinates (platform molecule) using a homogeneous catalyst and a heterogeneous catalyst (Al2(SO4)3). The third part is devoted to study the hydrolysis of methyl levulinate to levulinic acid using copper-based catalysts. Analytical techniques such as SEM, XRD, TPX were used to study the supported catalysts and understand their effect on the reaction. The fourth part of the project relates to the study of the production of 2-butanol from lignocellulosic biomass through the production of methyl levulinate and levulinic acid which are platform molecules and potentially substitutes for biodiesel. Thereafter, the levulinic acid is decarboxylated to 2-butanone and the latter is reduced to 2-butanol using bifunctional catalysts (such as Ru/C and Pt/C) under mild conditions. All of this work contributes to understanding the reactions of the new butanol production process

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46

Peña, Duque Leidy E. "Acid-functionalized nanoparticles for hydrolysis of lignocellulosic feedstocks". Thesis, Kansas State University, 2009. http://hdl.handle.net/2097/2201.

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Master of Science
Department of Biological and Agricultural Engineering
Donghai Wang
Acid catalysts have been successfully used for pretreatment of cellulosic biomass to improve sugar recovery and its later conversion to ethanol. However, use of acid requires a considerable equipment investment as well as disposal of residues. Acid-functionalized nanoparticles were synthesized for pretreatment and hydrolysis of lignocellulosic biomass to increase conversion efficiency at mild conditions. Advantages of using acid-functionalized metal nanoparticles are not only the acidic properties to catalyze hydrolysis and being small enough to penetrate into the lignocellulosic structure, but also being easily separable from hydrolysis residues by using a strong magnetic field. Cobalt spinel ferrite magnetic nanoparticles were synthesized using a microemulsion method and then covered with a layer of silica to protect them from oxidation. The silanol groups of the silica serve as the support of the sulfonic acid groups that were later attached to the surface of the nanoparticles. TEM images and FTIR methods were used to characterize the properties of acid-functionalized nanoparticles in terms of nanoparticle size, presence of sulfonic acid functional groups, and pH as an indicator of acid sites present. Citric acid-functionalized magnetite nanoparticles were also synthesized and evaluated. Wheat straw and wood fiber samples were treated with the acid supported nanoparticles at 80°C for 24 h to hydrolyze their hemicellulose fraction to sugars. Further hydrolysis of the liquid fraction was carried out to account for the amount of total solubilized sugars. HPLC was used to determine the total amount of sugars obtained in the aqueous solution. The perfluroalkyl-sulfonic acid functional groups from the magnetic nanoparticles yielded significantly higher amounts of oligosaccharides from wood and wheat straw samples than the alkyl-sulfonic acid functional groups did. More stable fluorosulfonic acid functionalized nanoparticles can potentially work as an effective heterogeneous catalyst for pretreatment of lignocellulosic materials.

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47

Ndimande, Sandile. "Increasing cellulosic biomass in sugarcane". Thesis, Stellenbosch : Stellenbosch University, 2014. http://hdl.handle.net/10019.1/86296.

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

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48

Kučera, Dan. "Využití lignocelulózových materiálů k biotechnologické produkci polyhydroxyalkanoátů". Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2015. http://www.nusl.cz/ntk/nusl-217161.

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Tato diplomová práce se zabývala možnostmi utilizace lignocelulosového materiálu jako obnovitelného zdroje k produkci polyhydroxyalkanoátů (PHA) biotechnologickými metodami. Teoretická část práce se zaměřuje na charakterizaci rostlinné odpadní biomasy, její enzymatickou sacharifikaci a možnosti produkce a izolace hydrolytických enzymů. Dále se pak literární rešerše zabývá bakteriální produkcí PHA a možností využití lignocelulosové biomasy pro jejich produkci. V rámci experimentální části byly vybrané odpadní substráty hydrolyzovány chemickou a enzymatickou cestou. Jako odpadní substráty byly použity výlisky z jablek, hroznového vína a řepky olejné a kávová sedlina. Získané hydrolyzáty byly použity k produkci PHA bakteriálním kmenem Burkholderia cepacia. Nejslibnějším substrátem se jevily výlisky z jablek. Ukázalo se, že vybraný bakteriální kmen je schopen utilizovat odpadní substráty i bez předchozí úpravy. Supernatant po skončení kultivace jevil následující aktivity: proteasovou, lipasovou (0.47 nmol/(mL•min)), celulasovou pro CMC (6.05 nmol/(mL•min)) a filtrační papír (4.63 nmol/(mL•min)) a xylanasovou (1.71 nmol/(mL•min)). Tyto enzymy mohou představovat zajímavý vedlejší produkt výroby PHA z odpadních zemědělských materiálů. V rámci této práce byl také posouzen vliv délky kultivace a způsob hydrolýzy na výslednou produkci PHA a enzymatickou aktivitu průmyslově zajímavých enzymů.

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49

Moharreri, Ehsan. "Optimization, Scale Up and Modeling CO2-Water Pretreatment of Guayule Biomass". University of Akron / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=akron1313013654.

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50

Mok, Yiu Ki. "The role of adsorbed enzymes in determining the hydrolysis kinetics of pretreated lignocellulosic biomass". Thesis, University of British Columbia, 2015. http://hdl.handle.net/2429/52996.

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The cost-effective production of sugars from biomass continues to remain challenging, partly due to the relatively high enzyme/protein loading required to effectively hydrolyze pretreated lignocellulosic substrates. Previous works have shown conflicting observations regarding the correlation between enzyme adsorption and the hydrolytic performance of an enzyme mixture. Unfortunately, it has proven difficult to accurately determine the roles of adsorbed enzymes during the hydrolysis of lignocellulosic substrates, in part because of the interference that protein determination methods encounter from the release of sugars and other biomass derived materials, the lack of a hydrolysis strategy for hydrolysis with only adsorbed enzymes and the use of “model” substrates in many studies. To better understand the role that adsorbed enzymes play in cellulose deconstruction, it is important that we are able to accurately quantify protein distribution and enzyme performance. Various protein quantification assays were initially assessed for their ability to accurately and reproducibly quantify protein/enzymes during typical biomass hydrolysis conditions. However, the ninhydrin assay, which was the most promising assay due to its specificity for protein and compatibility with most compounds derived from lignocellulosic samples, still suffered from the incompatibility with sugar degradation products, long hydrolysis times and potentially wide-ranging standard deviations. To overcome these limitations, an accurate and rapid modified ninhydrin assay was developed which employed a sodium borohydride treatment to eliminate sugar interference followed by acid hydrolysis at 130ºC, reducing the overall reaction time to 4 hours. Utilizing the modified ninhydrin assay, the role of adsorbed enzymes in determining the rate and extent of hydrolysis of several different pretreated biomass substrates was then assessed. Once the distribution of enzymes reached equilibrium, after 60 minutes, those enzymes that were adsorbed or free in solution were separated by centrifugation and subsequently assessed for their ability to hydrolyze various cellulosic substrates at different enzyme loadings. It was apparent that the adsorbed enzymes were critically important as the removal of those enzymes in solution resulted in no significant decrease in the rate and extent of hydrolysis. By using the adsorbed enzymes, enzyme loadings could be reduced by up to 53% while resulting in similar hydrolysis yields.
Forestry, Faculty of
Graduate

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