高产蛋白酶菌株的分离、鉴定及酶学性质研究

该研究旨在从非传统环境（磷矿）中分离、筛选高产胞外蛋白酶菌株，对菌株进行形态学观察、生理生化和分子生物学鉴定，并研究其蛋白酶的酶学性质。结果表明，分离筛选到一株蛋白酶高产菌株，编号为PB5，该菌株被鉴定为贝莱斯芽孢杆菌（Bacillus velezensis），该菌株产胞外蛋白酶活力为562.3 U/mL，胞外蛋白酶的最适pH值为10，在pH 7～10有较好的pH稳定性；最适温度为60 ℃，20～50 ℃时有较好的稳定性；Na+、Mg2+、Mn2+、K+对蛋白酶活力有明显的促进作用；Fe2+、Ag+、乙二胺四乙酸（EDTA）、苯甲基磺酰氟（PMSF）、十二烷基硫酸钠（SDS）对蛋白酶活力有明显抑制效果。

Isolation,identification and enzymatic properties of a high-yield protease strain

The purpose of this study was to isolate and screen high-yield extracellular protease strains from non-traditional environment (phosphate rock), the selected strain was identified by morphological observation and physiological characteristics as well as molecular biological identification. The results showed that a strain (numbered PB5) with high protease production was isolated and identified as Bacillus velezensis. The extracellular protease activity of the strain was 562.3 U/ml. The optimal pH value of extracellular protease was 10, and it had good pH stability between pH 7-10. The optimum temperature was 60 ℃, and it has good stability at 20-50 ℃. Na+, Mg2+, Mn2+, K+ had obvious promoting effect on protease activity. Fe2+, Ag+, ethylene diamine tetraacetic acid (EDTA), phenylmethanesulfonyl fluoride (PMSF) and sodium dodecyl sulfate (SDS) had obvious inhibitory effect on protease activity.