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‐β‐d‐thiogalactoside (IPTG) concentration and induction temperature were optimized, with the result that the highest pyruvate oxidase yield (4106·9 U l−1) of the recombinant E. colipET28a‐pod was obtained under conditions of 25°C, 0·5 mmol l−1 IPTG, 0·5 OD600, after 24 h of induction, which was 34·2 times the yield achieved with the wild‐type strain. The soluble pyruvate oxidase contributed 99·6% of the total pyruvate oxidase expressed. This study demonstrates that a highly soluble pyruvate oxidase can be obtained in recombinant Escherichia coli by optimizing vectors and induction conditions. The pyruvate oxidase yield achieved is the highest reported so far, which provides a convenient and cost‐saving way to produce pyruvate oxidase. This research promotes pyruvate oxidase application in the pharmaceutical and biochemical industries.