MntH与含锰过氧化氢酶共表达基因工程菌的构建与发酵优化

Construction of Co-expressed MntH and Mn-catalase Gene in Escherichia coli and Optimization of Fermentation Conditions

构建Mn2+转运蛋白MntH与来源于Thermus thermophilus HB27的含锰过氧化氢酶的共表达基因工程菌,并进行了发酵培养基及培养环境条件的优化,确定培养基中最佳的碳氮源种类及其浓度分别为:甘油7.0 g/L,酵母粉3.75 g/L和蛋白胨11.25 g/L;当培养基中的Mn2+浓度为1 mmol/L时,最佳的IPTG诱导浓度为0.05 mmol/L。此外,最佳的培养基初始p H值及培养温度分别为:p H 8.0和37℃,在最优发酵条件下工程菌摇瓶发酵培养24 h,过氧化氢酶活最高可达476 U/m L是未优化前3倍。在5 L发酵罐的验证实验中,过氧化氢酶的酶活进一步提高至1 094 U/m L。

Mn-catalase from Thermus thermophilus HB27 and Mn2＋transport protein MntH from Escherichia coli were co-expressed in E. coli BL21（DE3）. The optimization of fermentation medium and environment for the production of Mn-catalase was carried out at the shake flask level. The optimal carbon and nitrogen source were 7.0 g/L glycerine, 3.75 g/L yeast extract and 11.25 g/L peptone respectively. The optimum induced concentration of IPTG was 0.05 mmol/L while the Mn2＋in media was 1 mmol/L. In addition, the optimal initial pH of the medium and culture temperature were pH 8.0 and 37℃respectively. Under the optimal conditions, the maximal activity of catalase reached 476 U/mL, which was 3-fold of the control. Finally, in a 5 L fermentor the activity of catalase increased to 1 094 U/mL.