Strain HIT-3,which has good performances in cellulose degradation,was isolated from the campus soil. Based on the identification of conservative sequences 16S rDNA and the analysis of physiological-biochemical charact...Strain HIT-3,which has good performances in cellulose degradation,was isolated from the campus soil. Based on the identification of conservative sequences 16S rDNA and the analysis of physiological-biochemical characteristics,HIT-3 was identified as Achromobacter xylosoxidans. Denitrificans. A two-step fermentation process was conducted by adopting compound-bioflocculant-producing flora constructed by cellulose-degrading bacterium HIT-3 and flocculating bacterium F2. The cellulose degradation metabolites of HIT-3 was taken as substrates by flocculating bacterium F2,by which excellent compound bio-flocculant was obtained. In addition,the enzymology characteristics of HIT-3 were investigated when cultured in cellulose media,which utilized CMC-Na as its sole carbon. The results show that HIT-3 achieves a climax of 67.6 U/mL of enzyme production after incubation for 6 d,and the organic carbons produced are sufficient as the substrates required by the fermentation of flocculating bacterium F2(flocculating efficiency of 85.6%),which makes it feasible to reuse bioenergy.展开更多
The purpose of the paper was to study the effects of cellulolytic bacteria(CB)mixed with nitrogen-fixing bacteria(NFB)on fermentation in vitro.Nine CB strains and seven NFB strains were isolated from numen fluid of th...The purpose of the paper was to study the effects of cellulolytic bacteria(CB)mixed with nitrogen-fixing bacteria(NFB)on fermentation in vitro.Nine CB strains and seven NFB strains were isolated from numen fluid of three Holstein cows.Based onhigher activity of cellulose or nitrogenase,three CB types[CB-2(KT725624),CB-5(KT725623)and CB-6(KT725622)]and one NFB type[NFB-3(KT735054)]were screened out,respectively.Two parts were included in this study.The first part explored the optimal mixed ratio of CB to NFB through inoculating filter paper medium with the bacteria of 2×10^5 cfu·mL^-1.According to CMCase and FPase activities in the medium,the ratio of 4 to 1 was proven to be more effective.In the second part,rumen fermentation in vitro was conducted at 4:1 of CB to NFB,aiming at studying the effects of mixed bacteria.Six groups were classified,namely,control group(no bacteria),Group 1(CB-2+NFB-3),Group 2(CB-5+NFB-3),Group 3(CB-6+NFB-3),Group 4(NFB-3)and Group 5(CB-6).All the experimental groups had the same amount of bacteria(4×10^6 cfu·mL^-1)in the fermentation liquid.Samples were collected at 2,4,8,12 and 24 h of incubation.Compared with the groups with CB or NFB alone,gas production,dry matter degradability and bacterial protein expressions in the mixed groups increased.However,NH3-N concentration decreased and p H was stable.Meanwhile,related values among three mixed groups were significantly different;values in Group 2 were the best.展开更多
为探讨水稻秸秆饲料化的可行性,以中粳水稻秸秆为青贮原料,研究了添加乳酸菌和米糠对水稻秸秆青贮料品质的影响。将新鲜稻草切碎后加入添加物,设乳酸菌组、米糠组、乳酸菌+米糠组,乳酸菌添加量为1 kg鲜稻草中加入0.02 g 1.6×105CF...为探讨水稻秸秆饲料化的可行性,以中粳水稻秸秆为青贮原料,研究了添加乳酸菌和米糠对水稻秸秆青贮料品质的影响。将新鲜稻草切碎后加入添加物,设乳酸菌组、米糠组、乳酸菌+米糠组,乳酸菌添加量为1 kg鲜稻草中加入0.02 g 1.6×105CFU/g乳酸菌制剂,米糠添加量为1 kg鲜稻草中加入100 g米糠,同时设对照组(无添加物)。原料装入聚乙烯袋青贮,45 d后开袋检测。结果表明,与对照相比,乳酸菌组稻草青贮料的可溶性碳水化合物含量、干物质回收率、乳酸含量和乳酸/乙酸值分别提高了60.63%、3.82%、134.78%和332.64%,挥发性脂肪酸含量、氨态氮/总氮值分别降低了53.74%、36.68%,且差异均达显著水平(P<0.05);米糠组稻草青贮料的可溶性碳水化合物含量、干物质回收率、乳酸含量和乳酸/乙酸值较对照组分别提高了31.06%、17.08%、157.10%和349.31%,挥发性脂肪酸含量、氨态氮/总氮值分别降低了44.90%、46.68%,且与对照差异均达显著水平(P<0.05)。乳酸菌+米糠组的青贮料发酵品质最佳,除酸性洗涤纤维含量与对照差异不显著(P>0.05)外,其他指标均显著优于对照(P<0.05)。pH与挥发性脂肪酸含量呈较强的正相关性,而与乳酸含量和氨态氮/总氮值呈较强的负相关性。综合各测定指标结果表明,同时添加乳酸菌和米糠能更好地改善稻草青贮料品质。展开更多
基金Sponsored by the National Basic Research Program of China (Grant No. 2004CB418505)
文摘Strain HIT-3,which has good performances in cellulose degradation,was isolated from the campus soil. Based on the identification of conservative sequences 16S rDNA and the analysis of physiological-biochemical characteristics,HIT-3 was identified as Achromobacter xylosoxidans. Denitrificans. A two-step fermentation process was conducted by adopting compound-bioflocculant-producing flora constructed by cellulose-degrading bacterium HIT-3 and flocculating bacterium F2. The cellulose degradation metabolites of HIT-3 was taken as substrates by flocculating bacterium F2,by which excellent compound bio-flocculant was obtained. In addition,the enzymology characteristics of HIT-3 were investigated when cultured in cellulose media,which utilized CMC-Na as its sole carbon. The results show that HIT-3 achieves a climax of 67.6 U/mL of enzyme production after incubation for 6 d,and the organic carbons produced are sufficient as the substrates required by the fermentation of flocculating bacterium F2(flocculating efficiency of 85.6%),which makes it feasible to reuse bioenergy.
基金Supported by China Agriculture Research System(CARS-37)Northeast Agricultural University Innovation Funding for Postgraduate(yjscx14007)。
文摘The purpose of the paper was to study the effects of cellulolytic bacteria(CB)mixed with nitrogen-fixing bacteria(NFB)on fermentation in vitro.Nine CB strains and seven NFB strains were isolated from numen fluid of three Holstein cows.Based onhigher activity of cellulose or nitrogenase,three CB types[CB-2(KT725624),CB-5(KT725623)and CB-6(KT725622)]and one NFB type[NFB-3(KT735054)]were screened out,respectively.Two parts were included in this study.The first part explored the optimal mixed ratio of CB to NFB through inoculating filter paper medium with the bacteria of 2×10^5 cfu·mL^-1.According to CMCase and FPase activities in the medium,the ratio of 4 to 1 was proven to be more effective.In the second part,rumen fermentation in vitro was conducted at 4:1 of CB to NFB,aiming at studying the effects of mixed bacteria.Six groups were classified,namely,control group(no bacteria),Group 1(CB-2+NFB-3),Group 2(CB-5+NFB-3),Group 3(CB-6+NFB-3),Group 4(NFB-3)and Group 5(CB-6).All the experimental groups had the same amount of bacteria(4×10^6 cfu·mL^-1)in the fermentation liquid.Samples were collected at 2,4,8,12 and 24 h of incubation.Compared with the groups with CB or NFB alone,gas production,dry matter degradability and bacterial protein expressions in the mixed groups increased.However,NH3-N concentration decreased and p H was stable.Meanwhile,related values among three mixed groups were significantly different;values in Group 2 were the best.
