Optimised Expression and Activity Assessment of Bacterial Staphylokinase in E. coli BL21(DE3)

Abstract

The application of recombinant proteins is rare following the high production costs of expressing proteins with expensive inducers, such as isopropyl-β-D-1-thiogalactopyranoside (IPTG). Staphylokinase (SAK), a fibrinolytic enzyme, is a small bacterial thrombolytic agent that specifically clots and converts plasminogens to plasmins and lysis fibrin clots. The primary objective of the present investigation sought to increase the yield and lower the cost of staphylokinase production using Escherichia coli BL21 (DE3). Although the influence of the culture medium, culture density, and IPTG concentration on the production of SAK protein was explored. The results indicated that only culture density and concentration of IPTG were significant. This study achieved cost reduction by decreasing the IPTG inducer concentration (1.0 and 0.5 mM), which acted as the inducer. The production rate was also maintained or increased in low culture density. In conclusion, suitable production conditions, particularly diminished inducer concentration, effectively reduced upstream production costs and yielded high sak gene expression.