A Statistical Application for the Enhanced Production of Streptokinase from a Mutant Strain Streptococcus equinus VIT_VB2

Abstract

The present study focuses on media optimization of streptokinase (SK) production from the mutant strain EMS1 of Streptococcus equinus VIT_VB2 which was originally isolated from bovine milk. A two-level Plackett–Burman design was applied to screen key ingredients of the media (fructose, tryptose, KH2PO4, MgCl2, NaHCO3, CH3COONa, temperature, pH and incubation time). The dependent variables influencing SK production was further carried out using central composite design using response surface methodology. Statistical analysis revealed that the second-order model was found to be significant with R2 value of 0.9895. The production of SK was found to be high with supplementation of fructose, tryptose and potassium dihydrogen phosphate. The mutant strain EMS1 gave 2.06-fold higher SK production in the presence of optimized medium (663.53 U mL−1) than that of parent strain (wild strain) in minimal basal medium (321.5 U mL−1). The optimization of process parameters using response surface methodology resulted in a twofold increase in the yield of fibrinolytic enzyme.