Optimization of fermentation conditions for fibrinolysin from B. subtilis γ-DES36

The optimum fermentation conditions for the fibrinolysin from Bacillus subtilis γ-DES36 were investigated, and a mutant producing high-yield fibrinolysin was studied. The effects of inoculating amount, carbon source, nitrogen source, C/N ratio, surface activity agents and metal salts on the fibrinolysin production of mutant γ-DES36 were investigated, the fibrinolysin activity reached nearly 2900 IU/mL after adding maltose and tryptone. The best fermentation media were found to be: 1% maltose, 1% wheat bran, 0.5% tryptone, 1.5% soybean grit powder, 0.15% tween 40, 0.1% yeast extract, 0.25% K₂HPO₄,0.1% KH₂PO₄, 0.2 mL/(100 mL) mixture inorganic salts, and the proper inoculating amount 1%(v/v). The fibrinolysin activity of the fermented broth reached 2300 IU/mL.