Furfural is an important inhibitor in ethanol fermentation process using lignocellulosic hydrolysates as raw materials. In order to find out the furfural concentration range in which furfural inhibits the fermentation...Furfural is an important inhibitor in ethanol fermentation process using lignocellulosic hydrolysates as raw materials. In order to find out the furfural concentration range in which furfural inhibits the fermentation process, we used one strain Saccharomyces kluyveri selected from soil and cultured in several different furfural content media under low glucose concentration condition. Experiment results showed that microorganism growth was stimulated and dry cell weight decreased when furfural concentration in the medium was 0.25 mg/ml. Furfural had negative effect on cell growth when its concentration was above 1.00 mg/ml. At the same time, the strain growed better and had a higher glucose consumption rate in 5% original glucose concentration condition than in 3% original glucose concentration condition. The results showed that appropriate exaltation of original glucose concentration in stalk hydrolysates will increase the strain resistance to furfural.展开更多
In ethanol fermentation of Saccharomyces cerevisiae （S. cerevisiae）, glycerol is one of the main by-products. The purpose of this investigation was to increase ethanol yield through minimizing glycerol yield by usin...In ethanol fermentation of Saccharomyces cerevisiae （S. cerevisiae）, glycerol is one of the main by-products. The purpose of this investigation was to increase ethanol yield through minimizing glycerol yield by using mutants in which FPS1 encoding a channel protein that mediates glycerol export and GPD2 encoding one of glycerol-3-phosphate dehydrogenase were knocked-out using one-step gene replacement. GLT1 and GLN1 that encode glutamate synthase and glutamine synth.etase, respectively,were overexpressed using two-step gene replacment in fpsl△gpd2△ mutant.The fermentation properties of ZAL69（fpsl△：：LEU2 gpd2△：：URA3） and ZAL808 （fps1△：：LEU2 gpd2△：：URA3 PPGK1-GLT1 PPGK1-GLN1） under microaerobic conditions were investigated and compared with those of wild type（DC124）. Consumption of glucose, yield of ethanol, yield of glycerol, acetic acid, and pyruvic acid were monitored. Compared with wild type, the ethanol yield of ZAL69 and ZAL808 were improved by. 13.17% and 6.66 %, respectively, whereas glycerol yield decreased by 37.4 % and 41.7 %. Meanwhile, acetic acia yield and pyruvic acid yield aecreasea aramatlcally comparea to wild type. Our results indicate that FPS1 and GPD2 deletion of S. cerevisiae resulted in reduced glycerol yield and increased ethanol yield, but simultaneous overexpression of GLT1 and GLN1 infps1△gpd2△ mutant did not have a higher ethanol yield thanfps1△gpd2△ mutant.展开更多
Sweet sorghum is a promising energy crop due to its low fertilizer and water requirements,short growth period,and high biomass yield.However,the challenge for sweet sorghum as a feedstock for ethanol production is its...Sweet sorghum is a promising energy crop due to its low fertilizer and water requirements,short growth period,and high biomass yield.However,the challenge for sweet sorghum as a feedstock for ethanol production is its short harvest period and the extreme instability of its juice,both of which make achieving a year-round production process difficult.One way to solve this challenge and to meet the growing demand of bio-renewable ethanol is to incorporate sweet sorghum juice into the current dry-grind ethanol process.In the dry-grind process,the whole grain kernel is milled and fermented to produce ethanol.In this study,sweet sorghum juice with varying grain sorghum flour contents was liquefied,saccharified,fermented,and distilled to produce ethanol.Ethanol yield from sweet sorghum juice with the optimum grain sorghum flour loading was about 28% higher than that from the conventional ethanol process.Enzymatic hydrolysis with this process could be reduced by 30 min.The fermentation performance of sweet sorghum juice with grain flour using a raw starch hydrolyzing enzyme was also investigated,and ethanol yield was about 21% higher than that from the conventional process.This innovative technology enabling ethanol production from sweet sorghum juice could improve ethanol yield,save energy,and significantly decrease water use in the current dry-grind ethanol process.展开更多
Sweet sorghum (Sorghum bicolor [L.] Moench) accumulates fermentable sugars in the stem and is increasingly being studied as a potential source of feedstock for bioethanol production. The objective of this study was to...Sweet sorghum (Sorghum bicolor [L.] Moench) accumulates fermentable sugars in the stem and is increasingly being studied as a potential source of feedstock for bioethanol production. The objective of this study was to evaluate biomass and grain yield in five sweet sorghum cultivars (Dale, M81E, Sugar Drip, Della and Keller) and to determine quality of extractable juice and grain. Randomized complete block experiments were performed in the summer of 2009, 2010, and 2011. Leaf dry weight varied with year and cultivar and averaged 6177 kg·ha-1. Fresh stem weight ranged from 21 to 54 Mg·ha-1 with a mean across years and cultivars of 32.9 Mg·ha-1. Variations in stem weight were correlated with extractable juice volumes that ranged from 10 to 24 m3·ha-1. Juice Brix values fell within a narrow range (14% - 19%) across years and cultivars with an average of 15.6%. In all production years, theoretical sugar and ethanol yield were always numerically higher for Keller and M81E. Grain yield was lowest in Keller (90 kg·ha-1), but ranged from 400 to 1300 kg·ha-1 in other cultivars with a mean of 584 kg·ha-1 across years. However, Keller had the highest starch content with a lower proportion of resistant starch in the grain. Except for Keller, the cultivars tested are potential sources of both fermentable sugars and grain.展开更多
Strains K.marxianus Y-303,Oenoferm credo,Oenoferm rouge,Sacch.vini Rkaseteli-6,Sacch.cerevisiae XII and Sacch.uvarum 73 were used for fermentation of juice,extracted from Jerusalem artichoke tubers grown in Uzbekistan...Strains K.marxianus Y-303,Oenoferm credo,Oenoferm rouge,Sacch.vini Rkaseteli-6,Sacch.cerevisiae XII and Sacch.uvarum 73 were used for fermentation of juice,extracted from Jerusalem artichoke tubers grown in Uzbekistan.The fermentation process was carried out in laboratory conditions.Among these yeasts Oenoferm credo,Oenoferm rouge and Sacch.uvarum 73 showed higher performance than K.marxianus Y-303 and the ethanol yields were 92%,90%and 88%,respectively.After 72 h fermentation with Sacch.vini Rkaseteli-6 and Sacch.cerevisiae XII the yield of ethanol was 82%and 74%of maximum theoretical yield,respectively.展开更多
基金Project supported by the National Key Technology Research and Development Program of China(No.2006BAD07A01,2006BAD10B05-02).
文摘Furfural is an important inhibitor in ethanol fermentation process using lignocellulosic hydrolysates as raw materials. In order to find out the furfural concentration range in which furfural inhibits the fermentation process, we used one strain Saccharomyces kluyveri selected from soil and cultured in several different furfural content media under low glucose concentration condition. Experiment results showed that microorganism growth was stimulated and dry cell weight decreased when furfural concentration in the medium was 0.25 mg/ml. Furfural had negative effect on cell growth when its concentration was above 1.00 mg/ml. At the same time, the strain growed better and had a higher glucose consumption rate in 5% original glucose concentration condition than in 3% original glucose concentration condition. The results showed that appropriate exaltation of original glucose concentration in stalk hydrolysates will increase the strain resistance to furfural.
基金the National High Technology Research and Development Program of China(2002AA647040)
文摘In ethanol fermentation of Saccharomyces cerevisiae （S. cerevisiae）, glycerol is one of the main by-products. The purpose of this investigation was to increase ethanol yield through minimizing glycerol yield by using mutants in which FPS1 encoding a channel protein that mediates glycerol export and GPD2 encoding one of glycerol-3-phosphate dehydrogenase were knocked-out using one-step gene replacement. GLT1 and GLN1 that encode glutamate synthase and glutamine synth.etase, respectively,were overexpressed using two-step gene replacment in fpsl△gpd2△ mutant.The fermentation properties of ZAL69（fpsl△：：LEU2 gpd2△：：URA3） and ZAL808 （fps1△：：LEU2 gpd2△：：URA3 PPGK1-GLT1 PPGK1-GLN1） under microaerobic conditions were investigated and compared with those of wild type（DC124）. Consumption of glucose, yield of ethanol, yield of glycerol, acetic acid, and pyruvic acid were monitored. Compared with wild type, the ethanol yield of ZAL69 and ZAL808 were improved by. 13.17% and 6.66 %, respectively, whereas glycerol yield decreased by 37.4 % and 41.7 %. Meanwhile, acetic acia yield and pyruvic acid yield aecreasea aramatlcally comparea to wild type. Our results indicate that FPS1 and GPD2 deletion of S. cerevisiae resulted in reduced glycerol yield and increased ethanol yield, but simultaneous overexpression of GLT1 and GLN1 infps1△gpd2△ mutant did not have a higher ethanol yield thanfps1△gpd2△ mutant.
基金supported by National Science Foundation Grant:From Crops to Commuting:Integrating the Social,Technological,and Agricultural Aspects of Renewable and Sustainable Biorefining(I-STAR)NSF Award No.:DGE-0903701.
文摘Sweet sorghum is a promising energy crop due to its low fertilizer and water requirements,short growth period,and high biomass yield.However,the challenge for sweet sorghum as a feedstock for ethanol production is its short harvest period and the extreme instability of its juice,both of which make achieving a year-round production process difficult.One way to solve this challenge and to meet the growing demand of bio-renewable ethanol is to incorporate sweet sorghum juice into the current dry-grind ethanol process.In the dry-grind process,the whole grain kernel is milled and fermented to produce ethanol.In this study,sweet sorghum juice with varying grain sorghum flour contents was liquefied,saccharified,fermented,and distilled to produce ethanol.Ethanol yield from sweet sorghum juice with the optimum grain sorghum flour loading was about 28% higher than that from the conventional ethanol process.Enzymatic hydrolysis with this process could be reduced by 30 min.The fermentation performance of sweet sorghum juice with grain flour using a raw starch hydrolyzing enzyme was also investigated,and ethanol yield was about 21% higher than that from the conventional process.This innovative technology enabling ethanol production from sweet sorghum juice could improve ethanol yield,save energy,and significantly decrease water use in the current dry-grind ethanol process.
文摘Sweet sorghum (Sorghum bicolor [L.] Moench) accumulates fermentable sugars in the stem and is increasingly being studied as a potential source of feedstock for bioethanol production. The objective of this study was to evaluate biomass and grain yield in five sweet sorghum cultivars (Dale, M81E, Sugar Drip, Della and Keller) and to determine quality of extractable juice and grain. Randomized complete block experiments were performed in the summer of 2009, 2010, and 2011. Leaf dry weight varied with year and cultivar and averaged 6177 kg·ha-1. Fresh stem weight ranged from 21 to 54 Mg·ha-1 with a mean across years and cultivars of 32.9 Mg·ha-1. Variations in stem weight were correlated with extractable juice volumes that ranged from 10 to 24 m3·ha-1. Juice Brix values fell within a narrow range (14% - 19%) across years and cultivars with an average of 15.6%. In all production years, theoretical sugar and ethanol yield were always numerically higher for Keller and M81E. Grain yield was lowest in Keller (90 kg·ha-1), but ranged from 400 to 1300 kg·ha-1 in other cultivars with a mean of 584 kg·ha-1 across years. However, Keller had the highest starch content with a lower proportion of resistant starch in the grain. Except for Keller, the cultivars tested are potential sources of both fermentable sugars and grain.
文摘Strains K.marxianus Y-303,Oenoferm credo,Oenoferm rouge,Sacch.vini Rkaseteli-6,Sacch.cerevisiae XII and Sacch.uvarum 73 were used for fermentation of juice,extracted from Jerusalem artichoke tubers grown in Uzbekistan.The fermentation process was carried out in laboratory conditions.Among these yeasts Oenoferm credo,Oenoferm rouge and Sacch.uvarum 73 showed higher performance than K.marxianus Y-303 and the ethanol yields were 92%,90%and 88%,respectively.After 72 h fermentation with Sacch.vini Rkaseteli-6 and Sacch.cerevisiae XII the yield of ethanol was 82%and 74%of maximum theoretical yield,respectively.
基金Supported by the Project of Cultivating Innovation inGraduate Student of Jiangsu Province (2004) the Teaching and Research Award Program for OutstandingYoung Professor in Higher Education Institute (2003-2008)
