一株有机溶剂稳定性蛋白酶产生菌的筛选与鉴定

Screening and Identification of An Organic-solvent-stable Protease-producing Strain

为了筛选分泌有机溶剂稳定性蛋白酶耐有机溶剂极端微生物,利用添加苯10%(V/V)的MLB培养液从油污染水样中分离获得有机溶剂耐受菌株56株。通过产蛋白酶筛选培养基(SMA培养基)平板初筛和摇瓶发酵复筛从中筛选获得蛋白酶高产菌株DS1。通过形态学、生理生化及16SrDNA序列(GenbankEU578329)构建的系统进化树将菌株DS1鉴定为Bacillusaquaemaris。该菌株能耐受多种有机溶剂,并可以分泌有机溶剂稳定性蛋白酶。该蛋白酶在25%极性常数(logPOW)大于等于1.8的有机溶剂中稳定性好,于30℃、140r/min,培养14d仍有70%以上的活力。菌株DS1及其所分泌的蛋白酶均能较好的耐受有机溶剂,可以进行有机相催化,具有潜在的工业应用价值。

In this study, 56 organic-solvent-tolerant strains were isolated from oil-pollution water by using MLB medium with 10% benzene （V/V） addition. Among them, the high-yield strain DS1 was finally obtained through the first screening with SMA plate and the second screening with shake flask fermentation. The strain DS 1 was identified as Bacillus aquaemaris by its morphological, physiological, biochemical characteristics and 16S rDNA sequence homology. The verifying test showed that the strain DS 1 can tolerant organic solvents at different levels, and the organic-solvent-tolerant protease excreted by strain DS 1 also has a nice tolerance to organic solvents. This protease is stable in 25% organic solvents with logPo, equal to or more than 1.8, and may keep above 70% activity after 14-d cultivation at 30℃and 140 r/min. It was expected that both of the strain DS1 and its protease can be used as catalysts for reactions in organic phase, and have huge potential in industrial application.