嗜盐性蛋白酶产生菌Virgibacillus sp.P-4的筛选鉴定及其特性分析

摘要

Protease-producing bacteria were isolated from traditional shrimp sauce by using casein agar medium containing 10％ NaCl.Based on its morphological,biochemical and molecular properties,Virgibacillus sp.P-4 was determined as target strain for further study.The strain grew best at 30-37 ℃ with a salinity of 5％-15％.The protease produced by Virgibacillus sp.P-4 showed the optimum activity at 40 ℃,and was stable in the range of 20-50 ℃.The enzymatic activity reached its peak when NaCl concentration was 15％.Besides,VIrgibacillus sp.P-4 might produce more than one extracellular protease except sulfhydryl protease.According to the rate of release of free amino acids,the protease might preferably hydrolyze peptides containing Phe-,Tyr-,Lys-,His-,Pro-and Leu-.%利用酪蛋白琼脂平板从传统虾酱中分离嗜盐性蛋白酶产生菌,经形态学、生理生化和分子生物学鉴定,确定该菌隶属于枝芽孢杆菌属Virgibacillus sp.P-4,并用此菌为后续研究菌株.结果表明,该菌最适生长温度为30～37℃,最适生长NaC1质量分数为5％～15％;所产胞外蛋白酶在20～50℃条件下酶活力较高且保持稳定,最适反应温度为40℃,当NaC1质量分数为15％时酶活力达到最高,并且所产胞外蛋白酶种类可能不只一种,但不包含巯基蛋白酶;通过分析酶解液中游离氨基酸释放速率,预测其酶切位点为Phe-、Tyr-、Lys-、His-、Pro-及Leu-.