1株产纤维素酶细菌的筛选、鉴定及生长特性

摘要

分离筛选高效降解纤维素的菌株,并研究其生物学特性.利用刚果红染色法从腐烂的玉米秸秆中分离纤维素降解菌,再通过测定滤纸的降解率及多种酶活复筛.综合考虑水解圈和菌落直径(HC值),滤纸的降解率和酶活,对所筛选的菌株进行纤维素降解能力综合评价,最终获得1株具有纤维素降解能力的菌株DX4,其滤纸酶活(FPA酶活)、内切葡聚糖酶活力(CMC酶活)和外切葡聚糖酶活力(Cex酶活)分别为256.051、358.276和5.536 U/mL.结合形态学、生理生化特性和分子生物学鉴定,将该菌株鉴定为枯草芽胞杆菌(Bacillus subtilis),命名为Bacillus subtilis DX4,简称BS-DX4.研究表明,BS-DX4的最适生长温度为40℃,最适生长pH为7.0,低盐浓度下生长旺盛,是具有开发潜力的纤维素酶高产菌株.%The aim of this study was to screen efficient cellulose degradable strains and study their biological characteristics.The bacteria were isolated and screened from rotten maize straw by using the Congo red staining test,followed by measuring the degradation rate of filter paper and the enzyme activity for further-rescreening.The hydrolysis circle,clearing zone ratios (clearing zone diameter/colony diameter),the degradation rate of filter paper and cellulase activity were taken as comprehensive evaluating selection criteria,and obtained a cellulose-producing strain-DX4.The results showed that the filter paper (FPA),endoglucanase activity (CMCase activity),exoglucanase activity (Cex activity) of DX4 were 256.051 U/mL,358.276 U/mL,5.536 U/mL,respectively.Identified by morphological,physiology and biochemistry,molecular technology,DX4,with better cellulose degradable ability,it was characterized as Bacillus subtilis,and named as BS-DX4.The study indicated that the strain grew vigorously at 40 ℃ on medium with light salt concentration.It is a high cellulase-producing strain with broad development potential.