The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform
Akihiko Kondo - One of the best experts on this subject based on the ideXlab platform.
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Co-expression of TAL1 and ADH1 in recombinant xylose-fermenting Saccharomyces cerevisiae improves ethanol production from Lignocellulosic Hydrolysates in the presence of furfural
Journal of Bioscience and Bioengineering, 2013Co-Authors: Tomohisa Hasunuma, Ku Syahidah Ku Ismail, Yumiko Nambu, Akihiko KondoAbstract:Lignocellulosic biomass dedicated to bioethanol production usually contains pentoses and inhibitory compounds such as furfural that are not well tolerated by Saccharomyces cerevisiae. Thus, S. cerevisiae strains with the capability of utilizing both glucose and xylose in the presence of inhibitors such as furfural are very important in industrial ethanol production. Under the synergistic conditions of transaldolase (TAL) and alcohol dehydrogenase (ADH) overexpression, S. cerevisiae MT8-1X/TAL–ADH was able to produce 1.3-fold and 2.3-fold more ethanol in the presence of 70 mM furfural than a TAL-expressing strain and a control strain, respectively. We also tested the strains' ability by mimicking industrial ethanol production from hemicellulosic Hydrolysate containing fermentation inhibitors, and ethanol production was further improved by 16% when using MT8-1X/TAL–ADH compared to the control strain. Transcript analysis further revealed that besides the pentose phosphate pathway genes TKL1 and TAL1, ADH7 was also upregulated in response to furfural stress, which resulted in higher ethanol production compared to the TAL-expressing strain. The improved capability of our modified strain was based on its capacity to more quickly reduce furfural in situ resulting in higher ethanol production. The co-expression of TAL/ADH genes is one crucial strategy to fully utilize undetoxified Lignocellulosic Hydrolysate, leading to cost-competitive ethanol production.
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deletion of the pho13 gene in saccharomyces cerevisiae improves ethanol production from Lignocellulosic Hydrolysate in the presence of acetic and formic acids and furfural
Bioresource Technology, 2012Co-Authors: Keisuke Fujitomi, Tomoya Sanda, Tomohisa Hasunuma, Akihiko KondoAbstract:Abstract For efficient bioethanol production from Lignocellulosic biomass by Saccharomyces cerevisiae, it is necessary to improve cellular tolerance to toxic compounds released during the pretreatment of biomass. The gene encoding p-nitrophenylphosphatase, PHO13, was disrupted in a recombinant xylose-fermenting S. cerevisiae strain, which improved ethanol production from xylose in the presence of three major inhibitors, acetic and formic acids, and furfural. In medium supplemented with 30 mM acetic acid, the ethanol yield obtained by the ΔPHO13 mutant was 0.45 g-ethanol/g-xylose. Notably, the specific ethanol productivity of the mutant in the presence of 90 mM furfural was fourfold higher than that of the control strain. The PHO13-disrupted strain produced ethanol from rice straw Hydrolysate obtained by liquid hot-water pretreatment with a greater than fourfold higher xylose consumption rate than the control. Together, our findings demonstrate that PHO13 deletion is a simple, but effective, approach for improving cellulosic bioethanol production by S. cerevisiae.
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repeated batch fermentation of Lignocellulosic Hydrolysate to ethanol using a hybrid saccharomyces cerevisiae strain metabolically engineered for tolerance to acetic and formic acids
Bioresource Technology, 2011Co-Authors: Tomoya Sanda, Tomohisa Hasunuma, Fumio Matsuda, Akihiko KondoAbstract:A major challenge associated with the fermentation of lignocellulose-derived Hydrolysates is improved ethanol production in the presence of fermentation inhibitors, such as acetic and formic acids. Enhancement of transaldolase (TAL) and formate dehydrogenase (FDH) activities through metabolic engineering successfully conferred resistance to weak acids in a recombinant xylose-fermenting Saccharomyces cerevisiae strain. Moreover, hybridization of the metabolically engineered yeast strain improved ethanol production from xylose in the presence of both 30 mM acetate and 20 mM formate. Batch fermentation of Lignocellulosic Hydrolysate containing a mixture of glucose, fructose and xylose as carbon sources, as well as the fermentation inhibitors, acetate and formate, was performed for five cycles without any loss of fermentation capacity. Long-term stability of ethanol production in the fermentation phase was not only attributed to the coexpression of TAL and FDH genes, but also the hybridization of haploid strains.
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Ethanol fermentation from Lignocellulosic Hydrolysate by a recombinant xylose- and cellooligosaccharide-assimilating yeast strain
Applied Microbiology and Biotechnology, 2006Co-Authors: Satoshi Katahira, Atsuko Mizuike, Hideki Fukuda, Akihiko KondoAbstract:The sulfuric acid Hydrolysate of Lignocellulosic biomass, such as wood chips, from the forest industry is an important material for fuel bioethanol production. In this study, we constructed a recombinant yeast strain that can ferment xylose and cellooligosaccharides by integrating genes for the intercellular expressions of xylose reductase and xylitol dehydrogenase from Pichia stipitis , and xylulokinase from Saccharomyces cerevisiae and a gene for displaying β-glucosidase from Aspergillus acleatus on the cell surface. In the fermentation of the sulfuric acid Hydrolysate of wood chips, xylose and cellooligosaccharides were completely fermented after 36 h by the recombinant strain, and then about 30 g/l ethanol was produced from 73 g/l total sugar added at the beginning. In this case, the ethanol yield of this recombinant yeast was much higher than that of the control yeast. These results demonstrate that the fermentation of the lignocellulose Hydrolysate is performed efficiently by the recombinant Saccharomyces strain with abilities for xylose assimilation and cellooligosaccharide degradation.
Harald J Ruijssenaars - One of the best experts on this subject based on the ideXlab platform.
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isolation and characterization of cupriavidus basilensis hmf14 for biological removal of inhibitors from Lignocellulosic Hydrolysate
Microbial Biotechnology, 2010Co-Authors: Nick Wierckx, Frank Koopman, Luaine Bandounas, Johannes H De Winde, Harald J RuijssenaarsAbstract:The formation of toxic fermentation inhibitors such as furfural and 5-hydroxy-2-methylfurfural (HMF) during acid (pre-)treatment of lignocellulose, calls for the efficient removal of these compounds. Lignocellulosic Hydrolysates can be efficiently detoxified biologically with microorganisms that specifically metabolize the fermentation inhibitors while preserving the sugars for subsequent use by the fermentation host. The bacterium Cupriavidus basilensis HMF14 was isolated from enrichment cultures with HMF as the sole carbon source and was found to metabolize many of the toxic constituents of Lignocellulosic Hydrolysate including furfural, HMF, acetate, formate and a host of aromatic compounds. Remarkably, this microorganism does not grow on the most abundant sugars in Lignocellulosic Hydrolysates: glucose, xylose and arabinose. In addition, C. basilensis HMF14 can produce polyhydroxyalkanoates. Cultivation of C. basilensis HMF14 on wheat straw Hydrolysate resulted in the complete removal of furfural, HMF, acetate and formate, leaving the sugar fraction intact. This unique substrate profile makes C. basilensis HMF14 extremely well suited for biological removal of inhibitors from Lignocellulosic Hydrolysates prior to their use as fermentation feedstock. © 2009 The Authors.
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Isolation and characterization of Cupriavidus basilensis HMF14 for biological removal of inhibitors from Lignocellulosic Hydrolysatembt
Microbial Biotechnology, 2010Co-Authors: Nick Wierckx, Frank Koopman, Luaine Bandounas, Johannes H De Winde, Harald J RuijssenaarsAbstract:The formation of toxic fermentation inhibitors such as furfural and 5-hydroxy-2-methylfurfural (HMF) during acid (pre-)treatment of lignocellulose, calls for the efficient removal of these compounds. Lignocellulosic Hydrolysates can be efficiently detoxified biologically with microorganisms that specifically metabolize the fermentation inhibitors while preserving the sugars for subsequent use by the fermentation host. The bacterium Cupriavidus basilensis HMF14 was isolated from enrichment cultures with HMF as the sole carbon source and was found to metabolize many of the toxic constituents of Lignocellulosic Hydrolysate including furfural, HMF, acetate, formate and a host of aromatic compounds. Remarkably, this microorganism does not grow on the most abundant sugars in Lignocellulosic Hydrolysates: glucose, xylose and arabinose. In addition, C. basilensis HMF14 can produce polyhydroxyalkanoates. Cultivation of C. basilensis HMF14 on wheat straw Hydrolysate resulted in the complete removal of furfural, HMF, acetate and formate, leaving the sugar fraction intact. This unique substrate profile makes C. basilensis HMF14 extremely well suited for biological removal of inhibitors from Lignocellulosic Hydrolysates prior to their use as fermentation feedstock.
Patrizia Contursi - One of the best experts on this subject based on the ideXlab platform.
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Bacillus coagulans MA-13: a promising thermophilic and cellulolytic strain for the production of lactic acid from Lignocellulosic Hydrolysate
Biotechnology for Biofuels, 2017Co-Authors: Martina Aulitto, Salvatore Fusco, Carl Johan Franzen, Simonetta Bartolucci, Patrizia ContursiAbstract:BackgroundThe transition from a petroleum-based economy towards more sustainable bioprocesses for the production of fuels and chemicals (circular economy) is necessary to alleviate the impact of anthropic activities on the global ecosystem. Lignocellulosic biomass-derived sugars are suitable alternative feedstocks that can be fermented or biochemically converted to value-added products. An example is lactic acid, which is an essential chemical for the production of polylactic acid, a biodegradable bioplastic. However, lactic acid is still mainly produced by Lactobacillus species via fermentation of starch-containing materials, the use of which competes with the supply of food and feed.ResultsA thermophilic and cellulolytic lactic acid producer was isolated from bean processing waste and was identified as a new strain of Bacillus coagulans, named MA-13. This bacterium fermented lignocellulose-derived sugars to lactic acid at 55 °C and pH 5.5. Moreover, it was found to be a robust strain able to tolerate high concentrations of Hydrolysate obtained from wheat straw pre-treated by acid-catalysed (pre-)hydrolysis and steam explosion, especially when cultivated in controlled bioreactor conditions. Indeed, unlike what was observed in microscale cultivations (complete growth inhibition at Hydrolysate concentrations above 50%), B. coagulans MA-13 was able to grow and ferment in 95% Hydrolysate-containing bioreactor fermentations. This bacterium was also found to secrete soluble thermophilic cellulases, which could be produced at low temperature (37 °C), still retaining an optimal operational activity at 50 °C.ConclusionsThe above-mentioned features make B. coagulans MA-13 an appealing starting point for future development of a consolidated bioprocess for production of lactic acid from Lignocellulosic biomass, after further strain development by genetic and evolutionary engineering. Its optimal temperature and pH of growth match with the operational conditions of fungal enzymes hitherto employed for the depolymerisation of Lignocellulosic biomasses to fermentable sugars. Moreover, the robustness of B. coagulans MA-13 is a desirable trait, given the presence of microbial growth inhibitors in the pre-treated biomass Hydrolysate.
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bacillus coagulans ma 13 a promising thermophilic and cellulolytic strain for the production of lactic acid from Lignocellulosic Hydrolysate
Biotechnology for Biofuels, 2017Co-Authors: Martina Aulitto, Salvatore Fusco, Carl Johan Franzen, Simonetta Bartolucci, Patrizia ContursiAbstract:The transition from a petroleum-based economy towards more sustainable bioprocesses for the production of fuels and chemicals (circular economy) is necessary to alleviate the impact of anthropic activities on the global ecosystem. Lignocellulosic biomass-derived sugars are suitable alternative feedstocks that can be fermented or biochemically converted to value-added products. An example is lactic acid, which is an essential chemical for the production of polylactic acid, a biodegradable bioplastic. However, lactic acid is still mainly produced by Lactobacillus species via fermentation of starch-containing materials, the use of which competes with the supply of food and feed. A thermophilic and cellulolytic lactic acid producer was isolated from bean processing waste and was identified as a new strain of Bacillus coagulans, named MA-13. This bacterium fermented lignocellulose-derived sugars to lactic acid at 55 °C and pH 5.5. Moreover, it was found to be a robust strain able to tolerate high concentrations of Hydrolysate obtained from wheat straw pre-treated by acid-catalysed (pre-)hydrolysis and steam explosion, especially when cultivated in controlled bioreactor conditions. Indeed, unlike what was observed in microscale cultivations (complete growth inhibition at Hydrolysate concentrations above 50%), B. coagulans MA-13 was able to grow and ferment in 95% Hydrolysate-containing bioreactor fermentations. This bacterium was also found to secrete soluble thermophilic cellulases, which could be produced at low temperature (37 °C), still retaining an optimal operational activity at 50 °C. The above-mentioned features make B. coagulans MA-13 an appealing starting point for future development of a consolidated bioprocess for production of lactic acid from Lignocellulosic biomass, after further strain development by genetic and evolutionary engineering. Its optimal temperature and pH of growth match with the operational conditions of fungal enzymes hitherto employed for the depolymerisation of Lignocellulosic biomasses to fermentable sugars. Moreover, the robustness of B. coagulans MA-13 is a desirable trait, given the presence of microbial growth inhibitors in the pre-treated biomass Hydrolysate.
Youngsoon Um - One of the best experts on this subject based on the ideXlab platform.
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In situ detoxification of Lignocellulosic Hydrolysate using a surfactant for butyric acid production by Clostridium tyrobutyricum ATCC 25755
Process Biochemistry, 2015Co-Authors: Kyung-min Lee, Ki Yeon Kim, Yunje Kim, Okkyoung Choi, Han Min Woo, Sung Ok Han, Byoung-in Sang, Youngsoon UmAbstract:Lignocellulosic degradation compounds, especially phenolic compounds, inhibit the fermentation of Clostridium strains. In this study, a simple in situ detoxification method using a surfactant was developed for butyric acid production by Clostridium tyrobutyricum ATCC25755. Tween 80, a non-ionic surfactant, was chosen to sequester inhibitors by forming micelles, consequently preventing direct contact of inhibitors with cell membranes. When Tween 80 was added during fermentation, butyric acid production was significantly enhanced in the presence of hydrophobic phenolics such as p-coumaric acid (0 vs. 3.1 g/L butyric acid) and ferulic acid (2.2 vs. 4.6 g/L butyric acid) even at 0.016 g/L of Tween 80 (corresponding to the critical micelle concentration). Lignin, a polyphenol compound in lignocellulose, was also detoxified by Tween 80. When Tween 80 was added to acid-pretreated rice straw Hydrolysate, butyric acid production significantly increased (0.1 vs. 8.7 g/L butyric acid), thus verifying detoxification effect of Tween 80 on Lignocellulosic Hydrolysate.
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Electrochemical detoxification of phenolic compounds in Lignocellulosic Hydrolysate for Clostridium fermentation
Bioresource Technology, 2015Co-Authors: Kyung-min Lee, Ki Yeon Kim, Yunje Kim, Okkyoung Choi, Han Min Woo, Kyoungseon Min, Sung Ok Han, Youngsoon UmAbstract:Lignocellulosic biomass is being preferred as a feedstock in the biorefinery, but Lignocellulosic Hydrolysate usually contains inhibitors against microbial fermentation. Among these inhibitors, phenolics are highly toxic to butyric acid-producing and butanol-producing Clostridium even at a low concentration. Herein, we developed an electrochemical polymerization method to detoxify phenolic compounds in Lignocellulosic Hydrolysate for efficient Clostridium fermentation. After the electrochemical detoxification for 10. h, 78%, 77%, 82%, and 94% of p-coumaric acid, ferulic acid, vanillin, and syringaldehyde were removed, respectively. Furthermore, 71% of total phenolics in rice straw Hydrolysate were removed without any sugar-loss. Whereas the cell growth and metabolite production of Clostridium tyrobutyricum and Clostridium beijerinckii were completely inhibited in un-detoxified Hydrolysate, those in detoxifying rice straw Hydrolysate were recovered to 70-100% of the control cultures. The electrochemical detoxification method described herein provides an efficient strategy for producing butanol and butyric acid through Clostridium fermentation with Lignocellulosic Hydrolysate.
Nick Wierckx - One of the best experts on this subject based on the ideXlab platform.
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isolation and characterization of cupriavidus basilensis hmf14 for biological removal of inhibitors from Lignocellulosic Hydrolysate
Microbial Biotechnology, 2010Co-Authors: Nick Wierckx, Frank Koopman, Luaine Bandounas, Johannes H De Winde, Harald J RuijssenaarsAbstract:The formation of toxic fermentation inhibitors such as furfural and 5-hydroxy-2-methylfurfural (HMF) during acid (pre-)treatment of lignocellulose, calls for the efficient removal of these compounds. Lignocellulosic Hydrolysates can be efficiently detoxified biologically with microorganisms that specifically metabolize the fermentation inhibitors while preserving the sugars for subsequent use by the fermentation host. The bacterium Cupriavidus basilensis HMF14 was isolated from enrichment cultures with HMF as the sole carbon source and was found to metabolize many of the toxic constituents of Lignocellulosic Hydrolysate including furfural, HMF, acetate, formate and a host of aromatic compounds. Remarkably, this microorganism does not grow on the most abundant sugars in Lignocellulosic Hydrolysates: glucose, xylose and arabinose. In addition, C. basilensis HMF14 can produce polyhydroxyalkanoates. Cultivation of C. basilensis HMF14 on wheat straw Hydrolysate resulted in the complete removal of furfural, HMF, acetate and formate, leaving the sugar fraction intact. This unique substrate profile makes C. basilensis HMF14 extremely well suited for biological removal of inhibitors from Lignocellulosic Hydrolysates prior to their use as fermentation feedstock. © 2009 The Authors.
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Isolation and characterization of Cupriavidus basilensis HMF14 for biological removal of inhibitors from Lignocellulosic Hydrolysatembt
Microbial Biotechnology, 2010Co-Authors: Nick Wierckx, Frank Koopman, Luaine Bandounas, Johannes H De Winde, Harald J RuijssenaarsAbstract:The formation of toxic fermentation inhibitors such as furfural and 5-hydroxy-2-methylfurfural (HMF) during acid (pre-)treatment of lignocellulose, calls for the efficient removal of these compounds. Lignocellulosic Hydrolysates can be efficiently detoxified biologically with microorganisms that specifically metabolize the fermentation inhibitors while preserving the sugars for subsequent use by the fermentation host. The bacterium Cupriavidus basilensis HMF14 was isolated from enrichment cultures with HMF as the sole carbon source and was found to metabolize many of the toxic constituents of Lignocellulosic Hydrolysate including furfural, HMF, acetate, formate and a host of aromatic compounds. Remarkably, this microorganism does not grow on the most abundant sugars in Lignocellulosic Hydrolysates: glucose, xylose and arabinose. In addition, C. basilensis HMF14 can produce polyhydroxyalkanoates. Cultivation of C. basilensis HMF14 on wheat straw Hydrolysate resulted in the complete removal of furfural, HMF, acetate and formate, leaving the sugar fraction intact. This unique substrate profile makes C. basilensis HMF14 extremely well suited for biological removal of inhibitors from Lignocellulosic Hydrolysates prior to their use as fermentation feedstock.