Streptokinase production from Streptococcus dysgalactiae subsp. equisimilis SK-6 in the presence of surfactants, growth factors and trace elements

Streptokinase is an extracellular protein secreted by various strains of streptococci and is used clinically as an intravenous thrombolytic agent for the treatment of acute myocardial infarction. It is well established that the fibrinolytic activity of streptokinase originates in its ability to activate plasminogen. The present investigation was carried out to determine the extent of streptokinase production by Streptococcus dysgalactiae subsp. equisimilis SK-6, in the presence of surfactants, growth factors, trace elements and under the influence of different physical parameters. Mineral salt medium was supplemented with different surfactants, growth factors and trace elements. Effects of incubation period and inoculum volume were also studied. Results indicated that the streptokinase yield was higher in the presence of non-ionic surfactants, where Tween 80 supported maximum enzyme production (0.178 U/ml). Growth factors such as glycine and thiamine supplementation resulted in better enzyme production. Trace elements in the form of magnesium sulphate and ferrous sulphate when added in lesser quantity aided higher streptokinase synthesis. Enzyme production was severely affected in the presence of higher concentrations of these inorganic salts. A constant decrease in the enzyme production was observed beyond 48 h of incubation. Among the different inoculum sizes used, 1 % v/v inoculum facilitated highest streptokinase production (0.360 U/ml). The streptokinase production ability of S. dysgalactiae subsp. equisimilis SK-6 offers its potential industrial application for the manufacture of streptokinase.