Lijun Zhang, Tanvir Ahmad, Zongheng Ru and Yang Liu*
School of Food Science and Engineering, Foshan University/National Technical Center (Foshan) for Quality Control of Famous and Special Agricultural Products (CAQS-GAP-KZZX043)/ Guangdong Key Laboratory of Food Intelligent Manufacturing, Foshan 528231, Guangdong, P. R. China
*Corresponding author: liuyang@fosu.edu.cn
Bacillus velezensis strain exhibits notable potential for mycotoxin degradation. However, its industrial use is restricted by low cell density during fermentation. This study optimized medium composition and key environmental parameters to achieve high-cell-density fermentation of B. velezensis strain, using OD??? as the evaluation index. Single-factor experiments were conducted to screen carbon and nitrogen sources and to determine optimal temperature, initial pH, liquid volume, and inoculum size. Sorbitol was the most effective carbon source, with an optimal concentration of 40g/L, while 10g/L soybean peptone enhanced biomass accumulation. The optimal fermentation conditions were 37°C, an initial pH of 7.0, a 40% medium volume, and a 3% inoculum size. Under these conditions, B. velezensis reached an OD??? of 1.257 after 12h, representing a 52.36% increase compared with the baseline. This optimized, low-cost fermentation process provides a practical basis for pilot-scale production and industrial application of B. velezensis strain as a biological control agent.