一株耐酒精纤维素酶产生菌的筛选、鉴定及其特性研究

Screening, identification of an alcohol-tolerance cellulase-producing strain and its characteristics

利用乙醇-CMC-Na平板初筛,经摇瓶发酵复筛,从谷酒成熟酒醪中筛选获得1株耐酒精纤维素酶活力较高的细菌Lys-1249。经生理生化测定、形态观察及16S r DNA基因序列的同源性分析,将其鉴定为枯草芽孢杆菌(Bacillus subtilis)。经正交试验优化该菌株的产酶条件,表明该菌株在麸皮2.0%,蛋白胨0.6%,K2HPO40.1%,Mg SO4·7H2O 0.05%,Fe SO4·7H2O 0.02%,Mn SO40.01%,培养基初始p H值为7.0,培养温度37℃,发酵周期48 h的条件下,其耐酒精纤维素酶活力达到158.54 U/m L。该菌株在6.0%vol乙醇培养基中生长良好,活性可保持65.95%。

An ethanol-tolerant strain Lys-1249 with cellulase activity was screened from the mature fermented grain mash by ethanol-CMC-Na plate preliminary screening and shake flask fermentation affination. Strain Lys-1249 was identified as Bacillus subtilis according to morphological observation, physiological and biochemical determination and 16S rDNA sequence analysis. The cellulose-producing condition was optimized by orthogonal experiment, and results showed that the ethanol-tolerant cellulase activity reached 158.54 U/ml when strain Lys-1249 was cultured in the condition of wheat bran 2.0%, peptone 0.6%, K2HPO4 0.1%, MgSO4.7H2O 0.05%, FeSO4 7H2O 0.02%, MnSO4 0.01%, initial pH 7.0, temperature 37 ℃ and time 48 h. The strain also grew well in medium with 6.0%vol ethanol, and the cellulase activity can keep at 69.95%.