试验旨在研究不同水平酿酒酵母发酵白酒糟(yeast culture for white distiller's grains,YCDG)对蛋鸡生产性能、蛋品质、粪便菌群微生物的影响。试验选用体重接近,健康状态良好的419日龄海兰褐蛋鸡864只,随机分成3组,每组6个重复,...试验旨在研究不同水平酿酒酵母发酵白酒糟(yeast culture for white distiller's grains,YCDG)对蛋鸡生产性能、蛋品质、粪便菌群微生物的影响。试验选用体重接近,健康状态良好的419日龄海兰褐蛋鸡864只,随机分成3组,每组6个重复,每个重复48只。对照组饲喂玉米豆粕型基础饲粮,两个试验组分别在基础饲粮中添加1%和2%的YCDG。预饲期2周,试验期8周。结果表明:①各时间段内各组产蛋率差异不显著(P>0.05),但1%YCDG组产蛋率在1~4周、5~8周和全程比对照组分别提高2.17%,0.93%,1.55%;各组之间采食量差异显著(P<0.05),1~4周添加1%和2%YCDG组采食量显著高于对照组(P<0.05),5~8周2%YCDG组采食量显著高于1%YCDG组和对照组(P<0.05)。②蛋品质各项指标蛋壳厚度、蛋壳强度、哈夫单位、卵白高度、卵黄比例各组之间差异不显著(P>0.05),但添加YCDG组有增高趋势,1%和2%YCDG组蛋壳强度比对照组高5.56%,5.30%;2%YCDG组蛋壳颜色优于其他组。③1%和2%YCDG组粪便状态优于对照组(P>0.05),1%YCDG组粪便状态最佳;2%YCDG组粪便中乳酸杆菌数量显著高于对照组和1%YCDG组(P<0.05),对照组粪便中沙门氏菌数量显著高于1%和2%YCDG组(P<0.05),2%YCDG组沙门氏菌数量显著高于1%YCDG组(P<0.05)。综上,产蛋后期饲粮中添加1%~2%YCDG可提高采食量,改善生产性能、蛋品质,提高肠道健康水平,减少有害菌危害。展开更多
Propanoic acid accumulated in an ethanol-methane coupled fermentation process affects the ethanol fermentation by Saccharomyces cerevisiae. The effects of propanoic acid on ethanol production were examined in cassava ...Propanoic acid accumulated in an ethanol-methane coupled fermentation process affects the ethanol fermentation by Saccharomyces cerevisiae. The effects of propanoic acid on ethanol production were examined in cassava mash under different pH conditions. Final ethanol concentrations increased when undissociated propanoic acid was <30.0 mmol·L-1 . Propanoic acid, however, stimulated ethanol production, as much as 7.6% under proper conditions, but ethanol fermentation was completely inhibited when undissociated acid was >53.2 mmol·L-1 . Therefore, the potential inhibitory effect of propanoic acid on ethanol fermentation may be avoided by controlling the undissociated acid concentrations through elevated medium pH. Biomass and glycerol production decreased with propanoic acid in the medium, partly contributing to increased ethanol concentration.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
文摘试验旨在研究不同水平酿酒酵母发酵白酒糟(yeast culture for white distiller's grains,YCDG)对蛋鸡生产性能、蛋品质、粪便菌群微生物的影响。试验选用体重接近,健康状态良好的419日龄海兰褐蛋鸡864只,随机分成3组,每组6个重复,每个重复48只。对照组饲喂玉米豆粕型基础饲粮,两个试验组分别在基础饲粮中添加1%和2%的YCDG。预饲期2周,试验期8周。结果表明:①各时间段内各组产蛋率差异不显著(P>0.05),但1%YCDG组产蛋率在1~4周、5~8周和全程比对照组分别提高2.17%,0.93%,1.55%;各组之间采食量差异显著(P<0.05),1~4周添加1%和2%YCDG组采食量显著高于对照组(P<0.05),5~8周2%YCDG组采食量显著高于1%YCDG组和对照组(P<0.05)。②蛋品质各项指标蛋壳厚度、蛋壳强度、哈夫单位、卵白高度、卵黄比例各组之间差异不显著(P>0.05),但添加YCDG组有增高趋势,1%和2%YCDG组蛋壳强度比对照组高5.56%,5.30%;2%YCDG组蛋壳颜色优于其他组。③1%和2%YCDG组粪便状态优于对照组(P>0.05),1%YCDG组粪便状态最佳;2%YCDG组粪便中乳酸杆菌数量显著高于对照组和1%YCDG组(P<0.05),对照组粪便中沙门氏菌数量显著高于1%和2%YCDG组(P<0.05),2%YCDG组沙门氏菌数量显著高于1%YCDG组(P<0.05)。综上,产蛋后期饲粮中添加1%~2%YCDG可提高采食量,改善生产性能、蛋品质,提高肠道健康水平,减少有害菌危害。
基金Supported by the National High Technology Research and Development Program of China (2008AA10Z338)
文摘Propanoic acid accumulated in an ethanol-methane coupled fermentation process affects the ethanol fermentation by Saccharomyces cerevisiae. The effects of propanoic acid on ethanol production were examined in cassava mash under different pH conditions. Final ethanol concentrations increased when undissociated propanoic acid was <30.0 mmol·L-1 . Propanoic acid, however, stimulated ethanol production, as much as 7.6% under proper conditions, but ethanol fermentation was completely inhibited when undissociated acid was >53.2 mmol·L-1 . Therefore, the potential inhibitory effect of propanoic acid on ethanol fermentation may be avoided by controlling the undissociated acid concentrations through elevated medium pH. Biomass and glycerol production decreased with propanoic acid in the medium, partly contributing to increased ethanol concentration.
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.
