生防枯草芽孢杆菌B579补料分批发酵工艺优化

摘要

本论文对生防枯草芽孢杆菌B579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3.0-6.0 g/L,发酵过程控制pH为7.0,培养24h菌体浓度达到3.9×1010CFU/mL,继续培养至40h芽孢浓度达到2.8×1010 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.%In this research, the cell concentration and the final spore concentration were improved by optimizing 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 1010CFU/mL after 24 h cultivation and the spore concentration of 2. 8 1010CFU/mL was achieved after 40 h cultivation, respectively, which represent a 7.5 -fold and 7 —fold increasement compared with those of batch fermentation. Glucose 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 glucose will inhibit the sporulation B. subtilis.