High-level expression of Aerococcus viridans pyruvate oxidase in Escherichia coli by optimization of vectors and induction conditions

Pyruvate oxidase is an important enzyme used as a reagent in kits and biochemical analyses; however, the yield of pyruvate oxidase from wild microbial strains is low. In this study, high-level expression of Aerococcus viridans pyruvate oxidase was achieved in recombinant Escherichia coli by optimizing the expression system and induction conditions. Three recombinant pET vectors were constructed for pyruvate oxidase expression in E.coli. The isopropyl--d-thiogalactoside (IPTG) concentration and induction temperature were optimized, with the result that the highest pyruvate oxidase yield (41069Ul(-1)) of the recombinant E.colipET28a-pod was obtained under conditions of 25 degrees C, 05mmoll(-1) IPTG, 05 OD600, after 24h of induction, which was 342 times the yield achieved with the wild-type strain. The soluble pyruvate oxidase contributed 996% of the total pyruvate oxidase expressed.