Improvement of the production of vitamin B12 by Pseudomonas denitrifican through increasing the fermenter pressure
增大罐压提高脱氮假单胞菌发酵生产维生素B12的产量

Objective] The pressure of fermenter was enhanced in order to increase the concentration of vitamin B12. Methods] Metabolic flux analysis (MFA) was used to analyse the fermentation process of vitamin B12 production by Pseudomonas denitrifican. Results] The results indicated that the metabolic flux of oxaloacetic acid from phosphoenolpyruvate carboxylation was increased when the synthesis rate of vitamin B12 increased, in order to meet the demand for precursor supply to vitamin B12 production. A novel control strategy was designed as following. The pressure of fermenter was enhanced in order to increase the solubility of carbon dioxide in aqueous solution at steady phase of fermentation, so more carbon dioxide was carboxylated to oxaloacetic acid. The result showed that the concentration of vitamin B12 was 176 mg/L, 19.7% higher than the control batch (147 mg/L) at 160 hours. Conclusion] the production of vitamin B12 by Pseudomonas denitrifican was improved by increasing the fermenter pressure.