Abstract: In order to increase the spore yield, the fermentation technology of Bacillus subtilis 210 with antifungal activity was optimized. It was shown that the main factors influencing spore production were doses of corn flour, peptone and KH₂PO₄. The optimal fermentation medium was as follows: corn flour 10.75 g·L^-1, soybean meal 9.00 g·L^-1, peptone 6.97 g·L^-1, KH₂PO₄ 0.66 g·L^-1, NaCl 4.00 g·L^-1, MgSO₄·7H₂O 0.60 g·L^-1, CaCl₂ 3.00 g·L^-1 and MnSO₄·H₂O 0.60 g·L^-1. Based on the single factor optimization experiment results, the optimal culture conditions were as follows∶culture temperature 31 ℃,fluid volume 30 mL·250 mL^-1,inoculum size 4%. With the optimal fermentation condition, the spore yield of Bacillus subtilis 210 reached 1.64×10¹⁰ cfu·mL^-1, and was increased by 6.5 fold as compared with the spore yield before fermentation technology optimization.

Key words: Bacillus subtilis, fermentation technology, response surface analysis