Enhance Vitamin B12 Production by Online CO2 Concentration Control Optimization in 120 m3 Fermentation

Great amounts of carbon dioxide generated by Pseudomonas denitrificans during high aerobic vitamin B12 fermentation, while the influence of CO2 concentration on vitamin B12 production remains unclear. In this paper, we present parallel experiments to investigate various levels of inlet CO2 fractions on the physiological metabolism of P. denitrificans in laboratory scale fermentation. The results demonstrated that the oxygen transfer rate, cell growth and glucose consumption were inhibited with CO2 fraction elevated from 0.03% to 8.86 ± 0.24%, while the most exciting results showed that the specific vitamin B12 production rate and the yield to glucose were greatly stimulated when dissolved CO2 increased to 8.86 ± 0.24%. Therefore, the optimal exhausted CO2 fraction control strategy in 120 m 3 fermenter was established. With the exhaust CO2 concentration was well controlled at 7.5 ± 0.25% on-line, vitamin B12 production greatly improved to 223.7 ± 3.7 mg/L, which was 11.2% higher than that of control. This strategy was proved to be significant necessary and effective for successfully scale up optimization in industrial vitamin B12 fermentation. Enhance Vitamin B12 Production by Online CO2 Concentration Control Optimization in 120 m3 Fermentation