纳豆芽孢杆菌高密度发酵条件优化

为有效提高纳豆菌的产率，达到高密度发酵培养的效果，对纳豆芽孢杆菌高密度发酵培养的培养基成分和培养条件进行了优化试验。采用单因素和正交试验方法，最终确定最佳培养基为淀粉20．0g／L，酵母粉2．0g／L，蛋白胨2．0g／L，NH4C11．0g/L，K2HPO4 2．0g／L，KH2P042．0g／L，MgSO41．0g/L。最佳培养条件为：初始pH值6．5；接人菌种的体积分数为0．05；培养温度35℃。在20L发酵罐中高密度发酵培养，纳豆芽孢杆菌活菌数达2．95×10^14 cfu／L，较优化前提高近一个数量级。

Optimization of High-density Culture Fermentation of Bacillus natto

The liquid fermentation medium and conditions of Bacillus natto were optimized by single factor experiments and orthogonal experiments. The most suitable medium of spore forming was identified as follows： starch 20.0 g/L,yeast extract powder 20.0 g/L,NH4Cl 1.0 g/L,K2HP04 2.0 g/L,KH2PO4 2.0 g/L,MgSO4 1.0 g/L. The best fermentation condition was as follows ： initiative of pH was 8.0, culture temperature 35℃, and inoculation amount 0.05 （ φ = 0.05 ）. The productivity of Bacillus natto could reach up to 2.95 × 10^14 cfu/ L at the scale of 20 L scale fermentor. It provides the theoretical basis for the production of high density fermentation industry.