Isolation and Mutagenesis of Streptokinase Producing Bacteria

Of 103 β-haemolytic Streptococci (with haemolytic activity) in total were isolated from different samples of blood and biomass from infected throat, 47 isolates exhibited streptokinase (SK) activity. T3, identified as a new variant of Streptococcus equisimilis, was found to be excellent SK producer in submerged fermentation and was selected for strain improvement studies. This strain was mutagenized by UV and N-methyl-N'-nitro-N-nitroso guanidine (NTG). The isolation of mutants and the SK activity of selected mutants were described. The SK yield of the best UV mutant AUV10 was 120% higher than the wild strain (T3). Also, the SK yield of the best NTG mutant NUV7 was 146% higher than the wild strain (T3). The results indicated that UV and NTG were effective mutagenic agents for strain improvement of S. equisimilis T3 for enhanced SK productivity.