白酒酒醅纤维素降解菌的多样性分析及其分离筛选

摘要

Zaopei,a mixture of fermented grains used for Chinese Baijiu production,is a complex ecosystem that hosts diverse microbial communities that play important role in cereal fermentation.In this study,Cellulose-degrading bacteria (CDB) in Zaopei samples used for Strong-and Light-flavor Baijiu production were incubated in enrichment medium with sodium salt of caboxymethyl cellulose (CMC-Na) as the sole source of carbon.We performed denaturing gradient gel electrophoresis (DGGE) to explore the diversity of cellulolytic communities and varied cultivation methods to determine cellulolytic potential.DGGE analysis showed no significant differences in bacterial species diversity between the original Zaopei samples and enrichment culture (p ＜ 0.05),but the community structure in the enrichment culture was significantly different than that found for the original Zaopei samples.Sequencing of the DGGE bands allowed the identification of 5 bacterial genera (Acinetobacter,Bacillus,Klebsiella,Lactococcus and Paenibacillus) in the enrichment culture.To evaluate the cellulase activity of the CDB,the hydrolytic value of the colony on cellulose congo red agar media,carboxymethyl cellulase (CMCase) activity,and filter paper degradation ability were measured.Consequently,3 isolates (Paenibacillus sp.,Acinetobacter sp.and Gluconobacter sp.) with high cellulose-degrading properties were obtained.The results also indicated that significant synergistic straw degradation could be achieved in a mixed culture system of the 3 isolates and the degradation rate of rice-and wheat-straw were 35.32％ and 28.89％,respectively.The data presented in this study significantly increases the number of identified bacteria associated with cellulose degradation,and the biotechnological potential of these bacterial isolates should be explored in detail.%为拓展纤维素降解菌资源,将浓香和清香型白酒酒醅样品富集培养于羧甲基纤维素钠(sodium carboxymethyl cellulose,CMC-Na)液体培养基,利用变性梯度凝胶电泳技术(denaturing gradient gel electrophoresis,DGGE)和平板培养法研究富集培养物的细菌多样性,筛选高效纤维素降解菌.DGGE结果显示,原始酒醅样品和富集培养物的细菌多样性无显著差异(p＜0.05),但群落结构相似性较低;富集培养物中的细菌分类于Acinetobacter、Bacillus、Klebsiella、Lactococcus、Paenibacillus.经刚果红水解圈、纤维素酶(carboxymethyl cellulase,CM-Case)活力和滤纸条降解试验测定,获得3株纤维素降解力较强的细菌,分别为Paenibacillus sp.、Acinetobacter sp.和Gluconobacter sp..由这3株细菌构建的复合菌系在液态发酵条件下对水稻秸秆和小麦秸秆均具有显著的降解作用,降解率分别为35.32％和28.89％.白酒酒醅蕴藏高效的纤维素降解菌,具有开发利用潜力.