为提高菌体产量,获取更多目的蛋白产物,采用正交法和响应面法,优化益生菌枯草芽孢杆菌表达菌株Asr的发酵工艺。结果显示影响菌体产量最主要的3个因素为酵母浸粉、MgSO4和CaCl2。最佳发酵培养基配方为：蔗糖20 g/L、蛋白胨10 g/L、酵母浸粉8.65 g/L、K2HPO4 3.0 g/L、MgSO4 0.27 g/L、CaCl2 0.53 g/L。菌体产量较优化前提高了1.76倍,平均达到了3.25×108 CFU/mL。基于优化后的培养基,通过3 L发酵罐单因素试验优化发酵条件：最佳培养温度37 ℃、初始pH值7.0、接种量10%、搅拌转速为250 r/min。枯草芽孢杆菌Asr最高产量达到7.30×108 CFU/mL,试验结果为后续的发酵罐扩大培养提高生物产量奠定了基础。
In order to increase bacterial yield and obtain more target protein products, orthogonal method and response surface method were used to optimize the fermentation process of probiotic Bacillus subtilis expression strain Asr. The results showed that the three main factors affecting bacterial yield were leaching yeast powder, MgSO4 and CaCl2. The optimized fermentation medium formulation was: sucrose 20 g/L, peptone 10 g/L, leaching yeast powder 8.65 g/L, K2HPO4 3.0 g/L, MgSO4 0.27 g/L, CaCl2 0.53 g/L. The bacterial yield increased by 1.76-fold compared with that before optimization, with an average of 3.25×108 CFU/mL. After optimum of culture media, the fermentation conditions were optimized by single factor test in 3 L fermentor: the optimal temperature was 37 ℃, the initial pH value was 7.0, the inoculation volume was 10%, and the stirring speed was 250 r/min. The highest yield of Bacillus subtilis Asr reached 7.30×108 CFU/mL, and the test results laid a foundation for the subsequent expansion of fermentation tanks to increase biomass production.