塔里木大学学报

从土壤中筛选到两株能降解棉秆的纤维素分解菌M59、F115,通过构建酶活曲线确定了发酵周期,并进一步检测了不同氮源、不同浓度对菌株降解棉秆酶活的影响。结果表明,M59和F115均能有效降解纤维素,在刚果红纤维素平板上形成的水解圈直径>0.5cm,降解滤纸的CMC酶活>7.8 U.ml-1,FPA酶活>3.9 U.ml-1;两菌株均能降解棉秆且维持较高的酶活(CMC酶活>7.0 U.ml-1,FPA酶活>2.5 U.ml-1),发酵周期均确定为10d;氮源及其浓度对两菌株降解棉秆的CMC酶活和FPA酶活影响显著,以0.5%的酵母粉、蛋白胨作氮源,菌株M59的CMC酶活和FPA酶活、F115的CMC酶活均最高,可确定0.5%酵母粉、蛋白胨为两株纤维素分解菌较适宜的氮源。

Cotton stalk cellulose-decomposing microorganisms M59 and F115 were isolated from soil,cellulase activity curves were built and fermentation times were gained,on this basis,effects of nitrogen source and the concentration on cotton stalk decomposing cellulase activity were also measured.The results showed that the isolated strains M59 and F115 could decompose cellulose efficiently,which formed transparent ring on congo red cellulose plate with diameter>0.5cm,decomposed filter paper with CMCase activity>7.8 U·ml-1 and FPase activity>3.9 U·ml-1;tow strains could decompose cotton stalk with high cellulase activity(CMCase activity>7.8 U·ml-1 and FPase activity>3.9 U·ml-1),and the fermentation time were all confirmed as 10 days;nitrogen source and the concentration affected CMCase activity and FPase activity significantly of two strains decomposing cotton stalk,taking 0.5% yeast powder and peptone as nitrogen source,strain M59 achieved highest CMCase activity and FPase activity,F115 got the highest CMCase activity,so 0.5% yeast powder and peptone was considered as the fitting nitrogen source.