Journal of Bioprocessing & Biotechniques

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

Abstract

Ze-Jian Wang, Hui-Yuan Wang, Ping Wang, Yi-ming Zhang, Ju Chu, Ying-Ping Zhuang*, Si-Liang Zhang

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 m³ 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.