Optimization of Fermentation Conditions for Bacillus subtilis DPG-01

Fermentation culture medium and technological conditions of Bacillus subtilis DPG-01 were studied by single factor experiments and orthogonal experiments. The results showed that the optimum medium formula was 2.0 % bean cake, 0.1 % carbamide, 0.15 % corn steep liquor, 1.00 % cornstarch, 0.3 % K2HPO4, 0.15 % KH2PO4, 0.1 % MgSO4·7H2O and 0.02 % MnSO4·H2O. The optimum fermentation conditions were pH 7.5(initial value), amount of load 100 mL/500 mL flask, vibration frequency 200r.p.m and temperature 37±1℃. Under the optimum conditions the fermentation cell density was 9.1×109 CFU/mL with spore ratio of 90 %.