一株瘤胃纤维素降解菌的分离鉴定及其纤维素降解特性

Isolation, Identification and Characterization of a Cellulose-degrading Bacterial Strain from the Rumen of Sheep

从蒙古绵羊瘤胃内容物中分离到一株纤维素降解细菌WH-1,通过形态、生理生化特征、G+C mol%含量和16S rRNA序列分析对分离菌株进行鉴定,鉴定为溶纤维丁酸弧菌属(Butyrivibrio fibrisolvens)的溶纤维丁酸弧菌(Butyrivibrio fibrisolvens)。同时,用Mega4.1软件构建的系统发育树显示分离菌株WH-1与多株溶纤维丁酸弧菌(Butyrivibrio fibrisolvens)的亲缘关系最近。对该菌株纤维素降解特性的初步研究表明:当温度为37°C、pH值为7.0、接种量为25%、纤维二糖添加质量占总碳源质量的20%时,WH-1的72h滤纸降解率达到16.81%±2.99%。

A bacterial strain named as WH-1 that can degrade cellulose was isolated from the rumen of the Mongolia sheep. The isolate was identified as Butyrivibrio fibrisolvens based on phenotypic and morphol ogic properties, the G＋C mol% content of DNA and the 16S rRNA gene sequence analyses. In addition, the phylogenetic analysis of the 16S rRNA sequence also indicated that the isolate grouped closely with other members of Butyrivibrio fibrisolvens. The primary factors affecting the degradative ratio of cellulose were examined. The highest degradative ratio of filter paper reached 16.81%±2.99% under the conditions of 37℃, pH 7.0, inoculum size being 25%, and the percentage of cellobiose in total carbon sources being 20% within 72 hours of fermentation.