秸秆纤维素分解细菌的筛选与鉴定

Screening and Identification of Cellulose Decomposing Bacteria for Efficiently Degradating Straw

利用纤维素琼脂选择培养基和刚果红染色方法,从不同来源的土样中分离出2个菌株,测定了其纤维素酶活性、小麦秸秆降解能力,并对纤维素降解能力强的两个菌株进行了分子鉴定。结果表明,两株高效纤维素分解菌在纤维素刚果红培养基上均能形成透明水解圈,利用16S r RNA序列测序并分析Genbank中的同源性,结合形态和理化性质确定为Bacillus thuringiensis和Bacillus anthracis。在37℃,p H为7的条件下测定了纤维素酶活力,SC1-3和XR2-5-4分别为1.41和1.59。这两株37℃下经15 d后小麦秸秆失重率达19.92%和22.83%。

Using cellulose agar selective medium and Congo red staining method,the two strains were isolated from soil sam- ples from different sources. Activities of carboxymethyl cellulose （CMC） of these 2 strains were assayed during wheat straw fermentation. The 16S rDNA gene sequencing and blast search against the public database were used to identified SC1-3 and XR2-5-4. The results showed that the two strains with high cellulose decomposing bacteria in cellulose Congo red medium can form a transparent hydrolysis circle. The two strains were identified as Bacillus thuringiensis SC1-3,Bacillus artthracis XR2-5-4,based on their physiological,biochemical characterizations and 16S rDNA gene profiles. At the 37℃ and pH 7 condition,the activity of cellulase was determined and SC1-3 and XR2-5-4 were 1.41 U/mL and 1.59 U/mL,respectively. After the treatments of SC1-3 and XR2-5-4 strain for 15 days,wheat straw degradation rates were 19.92% and 22.83% respectvely.