Optimization of fed -batch fermentation process of biocontroi bacillus subtilis B579 | 生防枯草芽孢杆菌B579补料分批发酵工艺优化

Chinese. 本论文对生防枯草芽孢杆菌13579补料分批发酵工艺进行了优化，提高了菌体浓度和最终芽孢浓度，为生防菌剂的大规模生产奠定了基础。为获得较高的最终芽孢浓度，分别优化了葡萄糖补加时机、浓度控制范围以及发酵过程pH。利用7L发酵罐，当葡萄糖浓度降至3．0g／L时开始连续补加葡萄糖至3．0—6．0g／L，发酵过程控制pH为7．O，培养24h菌体浓度达到3．9×10. 0 CFU／mL，继续培养至40h芽孢浓度达到2．8×10. 0 CFU／mL，分别是分批发酵的7．5倍和7倍。发酵过程葡萄糖浓度对菌体生长和芽孢形成有较大影响，过高的葡萄糖浓度会抑制芽孢的生成，发酵过程控制合适的葡萄糖浓度有利于菌体浓度和芽孢浓度的提高。

English. In this research, the cell concentration and the final spore concentration were improved by optimi- zing the fed - batch fermentation process of biocontrol Bacillus subtilis B579, and this study provide the basis for biopesticide production in large scale. For obtaining a higher concentration of spores, the glucose -feed time, controlled glucose concentration and pH of medium was optimized, respectively. In a 7 L fermenter, the glucose was supplemented when its concentration was below 3.0 g/L and was controlled between 3.0 - 6.0 g/L. The fermentation pH was controlled as 7.0. In this condition, the cell concentration was 3.9 101~CFU/mL after 24 h cultivation and the spore concentration of 2.8 101~CFU/mL was achieved after 40 h cultivation, respec- tively, which represent a 7.5 - fold and 7 - fold increasement compared with those of batch fermentation. Glu- cose concentration showed a significant effect on cell growth and sporulation. It is important to control glucose - concentration for improving cell growth and the final spore concentration, because high concentration of glu- cose will inhibit the sporulation B. subtilis.