产脂肪酶重组枯草芽胞杆菌的发酵优化

Fermentation optimization of recombinant Bacillus subtilis producing lipase

笔者所在实验室前期筛选到1株产脂肪酶粘质沙雷氏菌,克隆其脂肪酶基因,构建重组枯草芽胞杆菌Bacillus subtilis 168/pMA5-lipA,成功实现了来源于粘质沙雷氏菌的脂肪酶基因在枯草芽胞杆菌中的表达。基于以上工作基础上,对B.subtilis 168/pMA5-lipA进行了摇瓶水平上的产酶发酵优化。首先通过单因素和正交试验确定了有利于产脂肪酶的最佳培养基成分,并对发酵条件进行了优化。结果表明:优化后的培养基组分为蔗糖35 g/L,玉米浆27.5 g/L,(NH4)2SO41.25 g/L,CaCl24 g/L,pH 7.0。在最优发酵培养基的条件下,37℃、160 r/min摇床培养33 h,每毫升发酵液中重组菌脂肪酶酶活可达98.6 U,是优化前的3倍。

A lipase-production Serratia marcescens was screened and its lipase coding gene was cloned to construct the recombinant Bacillus subtilis 168/pMA5-lipA.Lipase from Serratia marcescens was expressed in B.subtilis for the first time.In this study,fermentation optimization of B.subtilis 168/pMA5-lipA was carried out at the shake flask level.Medium compositions were optimized using single factor and orthogonal experiment.Furthermore, the optimization of culture conditions was performed.The optimal fermentation medium was as follows：sucrose 35 g/L,corn syrup 27.5 g/L,（ NH4 ） 2 SO4 1.25 g/L,CaCl2 4 g/L, and pH 7.0.The lipase yield reached 98.6 U/mL in the optimal fermentation medium and culture conditions,it was 3 times before the optimization.