一株碱性脂肪酶产生菌的分离鉴定及其产酶条件

从富含油脂的土壤中分离到90余株产脂肪酶的菌株。其中一株酶活较高的菌株N24液体发酵酶活达到19．5u·mL^-1。经细胞形态学分析、Biolog生理生化分析和16SrDNA序列比较表明该菌为嗜麦芽窄食单胞菌（Stenotrophomonas maltophilia）。对该菌株的液体发酵实验表明其最佳发酵培养基为：蛋白胨2．0％，可溶性淀粉3．0％，橄榄油1．0％，（NH4）2SO4 0．1％，MgSO4·7H2O 0．075％，K2HPO40．1％。该菌产生的脂肪酶最适反应温度为55踞，最适pH为9．0，属于碱性脂肪酶。该酶具有良好的热稳定性，在60℃处理60min酶活性基本保持不变。

Screening of An Alkaline Lipase Producing Strains and Its Fermentable Condition

More than 90 strains producing lipase were isolated from rich oil soil.The morphological identification. Biolog and 16S rDNA sequence analysis showed that one strain N24 with higher lipase activity was belonged to Stenotrophomonas maltophilia. The optimum medium component of fluid-state fermentation of lipase was peptone 2.0%. amiduln 3.0%, olive oil 1.0%. （NH4）SO4 0.1%, MgSO4-7H2O 0.075%, K2HPO4 0.1%. The optimum temperature and pH value for lipase activity were 55℃ and 9.0 respectively. The result indicated that it was typical alkaline lipase.The thermal stability of the enzyme was tested. The enzyme activity was not decreased when the alkaline lipase was heated at 60℃ for 60 min.