低温蛋白酶高产菌株的筛选、鉴定及培养条件优化

从慕士塔格峰江布拉克冰川融水中筛选获得一株耐低温蛋白酶细菌菌株P3-1,16S r DNA序列分析鉴定为假单胞菌,其分泌的蛋白酶最适催化温度为25℃,符合低温酶特性.通过单因子筛选及正交试验优化P3-1发酵条件,确定其最佳产酶培养基配比为:3.0%葡萄糖、1.5%蛋白胨、0.3%Mg SO4,最适宜培养条件为:接种量3%,p H 7.0,发酵时间42 h.在此条件下菌株发酵产酶活力可达82.1 U·m L~(-1),是最初(37.3 U·m L~(-1))的2.2倍.

Screening,identification and optimization of fermentation condition for a high-producing cold-active protease strain

A cold-adapted bacterial strain with high cold-active protease activity named P3-1 was isolated from melt water from Yangbark glacier of Muztag Ata, Xinjiang. It was identified as Pseudomonas sp. by 16S rDNA sequence analysis. The crud protease produced by strain P3-1 was of low-temperature enzyme with optimum reaction temperature 25 ℃. The medium components and culture conditions of strain P3-1 were optimized by single-factor and orthogonal test to improve the protease secretion capacity. Results indicated that the best medium components were as follows: 3. 0% glucose, 1. 5% peptone and 0. 3% MgSO4 , and the optimal culture conditions were initial inoculums 3%, pH 7.0, and 42 h for fermentation. In these conditions, the enzyme activity reached 82.1 U?mL-1 and 2.2-fold more than that of no optimization (37.3 U?mL-1).