一株高效纤维素降解菌株的分离鉴定及其酶学性质

Isolation and Identification of a Cellulose Degrading Bacterium and Its Cellulase Characterization

从黄浦江淀山湖的水底沉积物中筛选分离得到一株产纤维素酶的菌株。经细菌形态观察,生理生化实验并结合16SrRNA序列分析,鉴定该菌为蜡状芽孢杆菌(Bacillus cereus),同时发现其在系统发育树中处于一个独立的分支,推测该菌为Bacillus属中一个新的亚种。对该菌株产酶及酶活特性进行了初步研究,发现纤维素酶的产生与细菌的生长密切相关。该菌株在37°C,pH7.0的条件下,发酵66h后纤维素酶活达到最高值4.58U/mL。

A cellulose degrading strain DSH was isolated from the sediment of Dianshan Lake, Huangpu River, Shanghai. Basing on morphology, biochemical and physiological characterization, DSH was characterized as Bacillus cereus. A phylogenetic tree was constructed with the published 16S rRNA sequences of relative bacteria species. In the phylogenetic tree, the DSH strain is in a new branch which has the closest relative to Bacillus cereus strain JBE0004 with 99.78% sequence similarity. The generation of cellulose was closely correlated to its growth rate. The highest cellulose activity of DSH strain was 4.58 U/mL when grown at 37°C, pH 7.0 for 66 h.