Strain Improvement for Enhanced Production of Streptokinase and Streptodornase in Streptococcus sp.

Strain improvement for the enhanced production of streptokinase and streptodornase in Streptococcus sp. ATCC 12449 was performed. Strain UB111, a hyperproductive mutant which was isolated by use of nitrosoguanidine and selection of colonies with large clear zones on DNase test agar plates supplemented with $1{\%}$ glucose and $0.5{\%}$ ammonium chloride, produced about 3 fold more streptokinase and streptodornase than the wild type when tested in shake flask fermentations. The enhanced production of both streptokinase and streptodornase was achieved by cultivating the mutant in a pH-controlled fermentor containing fermentation medium enriched with yeast extract ($2.1{\%}$). Under these conditions, the mutant produced 7300 units/ml of streptokinase and 800 units/ml of streptodornase.