Rapid expression of pyruvate decarboxylase from Zymomonas mobilis in E. coli BL21 LysY/Iq

E. coli BL21 DE3 strain is commonly used to purify non-toxic prokaryotic proteins. Traditionally, IPTG based induction of the host strain at reduced temperatures for extended period (12-16 h) is performed to obtain high yield of functional proteins. It is desirable to explore methods which result in comparable yields of protein within a short period of time. We report rapid expression of pyruvate decarboxylase (PDC) enzyme from Zymomonas mobilis using E. coli BL21 LysY/I q as a host strain. High specific yield of purified PDC enzyme per unit biomass was obtained with a value of 0.084 (±0.005) mg/OD 600 after two-hour induction by 2.4 mM IPTG at 37 o C. The value was comparable to 0.095 (±0.012) mg/OD 600 obtained in case of control E. coli BL21 DE3 strain after 16 h induction by 0.1 mM IPTG at 18 o C. Highest specific activity of the purified PDC enzyme was observed at 37 o C induction and in the presence of 0.6 mM IPTG in both strains. The value of 191.8 (±19.9) of PDC purified from E. coli BL21 DE3 strain was comparable to 170.5 (±3.9) μmol/min/mg obtained from LysY/I q host. Based upon the data presented here, we propose that E. coli BL21 LysY/I q strain has potential to serve as a host for efficient and rapid expression (2 h) of non-toxic proteins. Results of this study will aid in cell free system studies which require rapid scale up of the complexity of metabolic pathways by utilizing multiple purified enzymes involved in bioconversion of the substrate of interest.