产原果胶酶菌株X4的鉴定及其培养基的优化

采用分子生物学的方法对前期实验中获得的一株产原果胶酶菌株X4进行了鉴定. 为了提高菌株X4所产的原果胶酶量, 采用响应面法优化了菌株X4的培养基组分. 结果显示, 菌株X4为Bacillus polyfermenticus, 其主要生长影响因子为淀粉、酵母提取物、胰蛋白胨. 在本实验条件下获得的最优培养基配方为淀粉3.45 g/L, 酵母提取物3.29 g/L, 胰蛋白胨5.68 g/L, 所产原果胶酶的酶活最高为51.35 U/mL, 是优化前的2.74倍.

Identification of protopectinase-producing strain X4 and optimization of medium

The purpose of the experiment was to identify protopectinase-producing bacteria X4 by molecular biology methods. To improve productivity of protopectinase, the X4 medium was optimized using a response surface method with enzyme activity as the index. The final result of X4 was Bacillus polyfermenticus. Starch, yeast extract and tryptone were found to be the main influencing factors. The optimal formula of the medium was determined: starch 3.45 g/L, yeast extract 3.29 g/L, and tryptone 5.68 g/L. The final activity of protopectinase was 51.35 U/mL, which was 2.74 times before optimization.