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

Abstract

Great amounts of carbon dioxide generated by Pseudomonas denitrificans during high aerobic vitamin B 12 fermentation, while the influence of CO 2 concentration on vitamin B 12 production remains unclear. In this paper, we present parallel experiments to investigate various levels of inlet CO 2 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 CO 2 fraction elevated from 0.03% to 8.86 ± 0.24%, while the most exciting results showed that the specific vitamin B 12 production rate and the yield to glucose were greatly stimulated when dissolved CO 2 increased to 8.86 ± 0.24%. Therefore, the optimal exhausted CO 2 fraction control strategy in 120 m 3 fermenter was established. With the exhaust CO 2 concentration was well controlled at 7.5 ± 0.25% on-line, vitamin B 12 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 B 12 fermentation.