秸秆纤维素降解菌的分离筛选、复合菌系构建及产酶条件优化

该研究采用刚果红染色法和滤纸条崩解法从山西老陈醋源中分离筛选纤维素降解菌，通过形态观察及分子生物学技术对其进行菌种鉴定。以滤纸酶活性为筛选指标构建复合菌系，采用单因素试验及响应面试验对其产酶发酵条件进行优化，并评价其对不同秸秆的降解效果。结果表明，筛选出3株纤维素降解菌，编号为J1、J2和J3，分别被鉴定为灿烂类芽胞杆菌（Paenibacillus lautus）、千叶类芽胞杆菌（Paenibacillus chibensis）和窖泥类芽胞杆菌（Paenibacillus vini）。3株菌等比例复配得到最佳复合菌系D，其最优产酶发酵条件为初始pH 7.4，接种量9%，发酵温度40℃。在此优化条件下，滤纸酶活性达到35.10 U/m L，是优化前的1.6倍。复合菌系D对不同秸秆均具有较好的降解效果，且对小麦秸秆的降解率最高，达27.63%。

Isolation and screening of straw cellulose degrading bacteria,construction of composite strains and optimization of enzyme production conditions

Cellulose degrading bacteria were isolated and screened from Shanxi aged vinegar source by Congo red staining and filter paper strip disintegration method, and the strains were identified by morphological observation and molecular biology techniques. The composite microbial system was constructed by using filter paper enzyme activity as screening index. The enzyme production fermentation conditions were optimized by single factor and response surface test, and its degradation effect on different straws were evaluated. The results showed that 3 cellulose degrading strains were screened and numbered as J1, J2 and J3, which were identified as Paenibacillus lautus, Paenibacillus chibensis and Paenibacillus vini, respectively. The optimal composite microbial system D was obtained by equal proportion of 3 strains, and the optimum fermentation conditions for enzyme production were initial pH 7.4, inoculum 9% and fermentation temperature 40 ℃. Under the optimized conditions, the filter paper enzyme activity reached 35.10 U/ml, which was 1.6 times that of before optimization. Composite microbial system D had a good degradation effect on different straws, and the degradation rate of wheat straw was the highest of 27.63%.