巨大芽孢杆菌发酵合成有机酸的条件优化OA

To improve the organic acid yield and substrate conversion efficiency in the fed-batch fermentation system of Bacillus megaterium,this study optimized the medium components and fermentation process control conditions using shake flasks and a 5 L bioreactor.An oxygen supply control strategy was guided by the quantitative oxygen uptake rate(OUR)and an optimal pH regulator composition was established for the fermentation process.The results show that the main factors affecting organic acid yield and substrate conversion efficiency are carbon source,MnSO4·H2O,pH value,oxygen supply level,and pH regulator composition.The optimal fermentation conditions are determined as follows:glucose as the carbon source,addition of 0.1 g/L MnSO4·H2O,pH controlled at 5.5 in a 5 L fermenter,moderate oxygen supply regulated by OUR feedback,and a mixture of NaOH and ammonia water at a ratio of 8∶2 as the pH regulator.Under these optimized conditions,the maximum organic acid yield reaches 165.61 g/L,and the glucose conversion rate reaches 50.41%.These results can effectively enhance the organic acid production efficiency and substrate conversion rate,providing reliable technical support for industrial scale-up production.