一株东祁连山耐低温纤维素降解菌株的分离、鉴定及产酶特性

Isolation,identification and characterization of a cold-adapted cellulosedegrading strain from eastern Qilian mountains

从东祁连山高寒草甸土壤中分离得到一株纤维素酶高产菌株X3-2。根据菌体形态观察、革兰氏染色反应及16SrDNA序列测定以及序列同源性比较，确定鉴定该菌为芽孢杆菌属的成员（Bacillus sp．）。对该菌的产纤维素酶条件研究结果表明：该菌在5℃～45℃、初始pH4．0～9．0的环境下均能产纤维素酶。在初始pH为8．0、盐浓度为2．0％～3．0％之间、培养温度为20℃培养条件下最适产酶。在5℃时，相对酶活仍能保持60％。

The strain X3-2 producing extracellular cellulase was isolated from eastern Qilian mountains and was identified as Bacillus sp. based on its morphological, biochemical physiological properties and 16S rDNA sequence analysis. The results of cellulase production research indicated that the strain X3-2 could produce cellulase at 5 ℃ ~ 45 ℃ 9.0. The most suitable culture conditions for enzyme production were temperature 20 ℃, pH 8.0, NaC1 2.0% Moreover, the relative enzyme activity still kept 60% at 5 ℃.