Abstract: In order to improve the growth efficiency of Bacillus coagulans, the effects of the appropriate carbon source, temperature, vitamin content, pH and oxidation stress in fermentation process on the growth and metabolism of Bacillus coagulans were investigated at the shaking flask and bioreactor level, and the fermentation medium was obtained. The optimum culture conditions in 30 L bioreactor were as follows： fermentation temperature was at 40 ℃, initial pH was 6.2~6.5, pH was controlled at 5.5 via the automatic addition of ammonia solution at 9~14 h during the culture process, control was stopped after pH above 5.5, and cysteine was added at a rate of 4.1 mg/（L·h） during the whole process. Under these conditions, the fermentation biomass reached 1.9×10¹⁰ CFU/mL at 13 h, which was 363.4% higher than that of the control, and the cell growth efficiency was 1.5×10⁹ CFU/（mL·h）, which was 305.4% higher than that of the control. It significantly increased the biomass and shortened the fermentation period, which provided an important reference for the industrial production of Bacillus coagulans.

Key words: Bacillus coagulans, batch fermentation, culture condition, oxidative stress