中度嗜盐菌Halobacillus sp. LY5的分离、鉴定及其胞外脂肪酶特性研究

A moderately halophilic bacterium Halobacillus sp. LY5 isolation and identification of and its lipase properties

利用吐温平板筛选法，从山西运城盐湖中分离获得一株高产胞外脂肪酶的中度嗜盐菌。通过形态学观察，生理生化特征及16SrRNA序列分析，初步鉴定并命名该菌为Halobacillus sp．LY5。酶学性质研究表明，该脂肪酶可在较宽温度范围内（30℃～90℃）保持高活力；在NaCl浓度为10％的反应缓冲体系（pH值8.0）中，温度为50℃，酶活性最佳。金属离子除Fe^3＋外，对酶活性均具有明显的抑制作用；而EDTA和SDS亦可不同程度的抑制酶活性。结果表明LY5所产脂肪酶可能存在某些特殊性质。

A moderately halophilic bacterium producing extracellular lipase was isolated from salt lake of Yuncheng of Shanxi province using tween plate method. Based on the morphological observations, physiological and biochemical characteristics and 16S rRNA sequence analysis, the strain was identified and named as Halobacillus sp. LY5. Properties of crude lipase indicated that it kept high activity over a broad temperature range （30℃-90℃）. Optimal activity was observed in 10% NaCl concentration at 50℃ and pH 8.0. The activity of crude lipase was markedly decreased in the presence of metal ions except Fe3＋, while EDTA and SDS also inhibited the enzyme activity.