High Cell Density Cultivation for the Production of Industrially Important Engineered Bi-functional Recombinant Staphylokinase Variant from Salt Inducible Escherichia coli GJ1158

Abstract

Most of the bacterial and other simple non glycosylated recombinant proteins were conventionally produced from IPTG inducible Escherichia coli BL21(DE3). Considering the factors like cost and toxic nature of IPTG, as an alternative, salt inducible Escherichia coli GJ1158 was used in this study for the over production of staphylokinase variant (sak – hirulog) using fed batch fermentation, cost effectively. Optimization of physico chemical factors viz., dissolved oxygen (DO), carbon, nitrogen and phosphate sources on bacterial growth for the production of recombinant sak – hirulog using batch and fed batch fermentation was studied. In batch culture, increased DO at more than 30 % did not influence the enhanced expression of sak – hirulog, but significant improvement was observed in fed batch cultivation. Supplementation of production medium with different nutrient sources like dextrose, yeast extract and dipotassium hydrogen phosphate (K2HPO4) enhanced the sak – hirulog expression in fed batch fermentation process even without disturbing the cell growth by providing 50 % DO. Approximately 1178 mg/L of specific protein was obtained using cost effective modified glucose yeast exgtract (GYE) media devoid of sodium chloride. This study also reports the highest concentration of recombinant protein from salt inducible expression host till to date, which manages to satisfy the production of bifunctional staphaphylokinase variant using economically feasible bacterial expression host Escherichia coli GJ1158.