巨大芽胞杆菌培养条件的研究

Culture Conditions for Bacillus megaterium

[目的]为了提高巨大芽胞杆菌的芽胞形成率及芽胞数量,为巨大芽胞杆菌芽胞制剂的产业化生产提供理论依据。[方法]通过单因子试验及正交试验对巨大芽胞杆菌JD-2发酵培养基和培养条件进行了研究。[结果]最适培养基组成为:玉米淀粉10.0g/L,蛋白胨5.0g/L,酵母膏5.0g/L,NaCl5.0g/L,CaCO31.0g/L,MgSO4·7H2O0.5g/L。确定最佳培养条件为:接种后起始芽胞浓度控制在106CFU/mL,初始pH值为7.0,培养温度为30℃,200r/min摇瓶培养,250mL三角瓶中最适装液体积为25mL。在15L自动发酵罐中扩大培养,控制溶氧在30%以上,培养22h,菌体浓度可达3.50×109CFU/mL,芽胞数量可达3.40×109CFU/mL,芽胞率达97.2%。[结论]试验获得的最佳培养条件可进一步应用于生产实际。

[Objective] To increase sporulation rate and spore concentration and offer the theoretical foundation for industrial production of Bacillus megaterium preparation. [Method] Fermentation culture medium and culture conditions of Bacillus megaterium JD-2 were studied by single factor test and orthogonal test. [Result] The optimum medium formula was composed of 10.0 g/L corn starch, 5.0 g/L peptone, 5.0 g/L yeast extract, 5.0 g/L NaCl, 1.0 g/L CaCO3 and 0.5 g/L MgSO4·7H2O. The optimum culture conditions are as follows： initial spore concentration, 10^6 CFU/mL; initial pH value, 7.0; culture temperature, 30 °C; shaking speed, 200 r/min; and volume, 25 mL medium in a 250 mL flask. When enlarge fermentation was performed in a 15 L auto fermentor with dissolved oxygen level less than 30%, cell concentration reached 3.50×10^9 CFU/mL, spore concentration reached 3.40×10^9 CFU/mL and sporulation rate reached 97.2% after 22 h culture. [Conclusion] The optimal culture conditions can be applied in practical production.