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

摘要

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.%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pH值及培养温度分别为：pH 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/mL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1094 U/mL。