Construction of Recombinant E.coli Expressing A Thermophilic Catalase and Its Application in H_2O_2 Wastewater Treatment

摘要

The recombinant plasmid pETac-CATHis with tac promoter was constructed for the constitutive expression of a thermophilic catalase in E.coli. And the effects of cultivation conditions of two recombinant strains, BL21(DE3)/pETac-CATHis and BL21(DE3)pLysS/pETac-CATHis, such as initial pH, cultivation temperature, cultivation time, and loading volume on catalase activity were investigated. The optimal cultivation conditions were: the initial pH 7.0, cultivation temperature 37°C, cultivation time 12 hours, and loading volume 25 mL in 100 mL flask. Under the optimal cultivation condition, the highest catalase activities of the two recombinant strains were 291.7 U/mL and 349.5 U/mL, respectively. After adding catalase, H_2O_2 in simulation H_2O_2 wastewater containing phenol was decomposed completely very quickly. Declining of catalase activity was detected with enhancing the phenol concentration, probably because the phenol might be a kind of competitive inhibitor for catalase.