复合乳酸菌提高干玉米秸秆微贮效果及产乙醇能力分析

Microbial pretreatment of dry corn stover with compound Lactobacillus for ethanol production

为提高干玉米秸秆的可生化性,文章参考强化微生物微贮原理,探讨接种复合乳酸菌对干玉米秸秆微贮品质的影响。以干玉米秸秆为原料,接种复合微生物干酪乳杆菌、发酵乳杆菌和粪链球菌,在不同时间取样分析微贮料的成分变化,以确定微贮指标,运用高通量测序技术分析微贮料的微生物组成和多样性,并考察秸秆微贮前后的微观变化及产乙醇潜力。研究结果表明:微贮料中的乳杆菌属是优势菌,厌氧发酵4周后,乳酸含量达到4.30%左右,p H值降低至4.22,微贮过程趋于稳定,这些都是微贮结束的指标;微贮料表面布满塌陷的孔洞,增加了酶或微生物的可及性;水洗后的微贮料利用酿酒酵母发酵56 h后,乙醇浓度达到32.76 g/L,乙醇转化率为57.21%。

In order to improve the biodegradability of dry corn stover, the feasibility of microbial pretreatment of dry corn stover with compound lactobacillus for ethanol production was investigated in this study. The inoculants product was composed of lactic acid-producing organisms, such as Lactobacillus casei, Lactobacillus fermentum and Enterococcus durans. After 4 weeks of anaerobic fermentation, the content of lactic acid was reached to 4.30%, while the p H value decreased to 4.22.These could be used as important indicators of the end of microbial silage. The 16 S r RNA gene-based pyrosequencing was used to analyze the community of the silage, while the results indicated that Lactobacillus was the advantageous species. The original dense complex lignocellulose structure was disrupted during ensiling, which lead to a lot of cracks and holes generated on the silage surface. These changes of microstructure increased the reaction area of microbes or enzymes. Ethanol concentration and the ethanol conversion rate of washed silage were 32.76 g/L and 57.21% by simultaneous saccharification and fermentation（SSF） for 56 h.