土壤中高产蛋白酶菌株的筛选鉴定及发酵条件优化

从海南土壤中筛选得到一株高产蛋白酶的菌株，并对其进行菌种鉴定、产蛋白酶发酵条件优化及蛋白酶分子质量测定。经筛 选，得到一株高产蛋白酶的菌株，编号为CAUH83，蛋白酶活力达到126 U/mL。 通过形态观察、生理生化试验及16S rDNA序列分析， 鉴定菌株CAUH83为粘质沙雷氏菌（Serratia marcescens）。 通过单因素试验优化，确定该菌株产蛋白酶的最优发酵条件：大豆粉3.0%、 蔗糖3.0%、初始pH 6.0、培养温度30 ℃、培养时间48 h。 在此优化发酵条件下，该菌株产蛋白酶酶活力达到1 932.3 U/mL，较优化前提 高15.3倍。 通过十二烷基硫酸钠-聚丙烯酰胺凝胶电泳（SDS-PAGE）和酶谱分析表明该蛋白酶分子质量约51 kDa。

Screening,identification and fermentation conditions optimization of a high yield protease strain from soil

A strain with high yield protease was isolated from soil sample of Hainan. The identification, fermentation conditions optimization and molecular mass of the strain were determined. After screening, a strain CAUH83 with high yield protease was obtained and the enzyme activity was 126 U/ml. Through morphological observation, physiological and biochemical tests and 16S rDNA sequence analysis, strain CAUH83 was identified as Serratia marcescens. The optimal fermentation conditions were optimized by single factor experiments as follows: soybean flour 3.0%, sucrose 3.0%,initial pH 6.0, culture temperature 30 ℃ and time 48 h. Under the optimal conditions, the highest protease activity of the strain was 1 932.3 U/ml,which increased 15.3 times higher than that of before optimization. The molecular mass of the protease was about 51 kDa by SDS-PAGE and protease zymogram analysis.