Optimization of expression of dha T gene encoding 1,3‐propanediol oxidoreductase from Klebsiella pneumoniae in Escherichia coli using the methods of uniform design and regression analysis

This paper is concerned with the optimization of expression conditions of 1,3‐propanediol oxidoreductase (PDOR) using the uniform design (UD) method and regression analysis. The concentration of the inducer isopropyl‐β‐ D ‐thiogalactopyranoside (IPTG), the induction temperature and the induction time, which were identified as three crucial factors, were optimized in 50 mL cultivation tubes containing 5 mL LB culture. The optimal expression conditions for enhanced PDOR activity were found to be an IPTG concentration of 0.1 mmol l −1 , an induction temperature of 21.2 °C and an induction time of 5 h. Subsequent experimental trials confirmed the validity of the model. These optimal expression conditions in the cultivation tube culture led to a PDOR activity of 9.25 U mL −1 , which was considerably higher than those obtained in the optimizing experimental trials. Copyright © 2005 Society of Chemical Industry