Effects and mechanisms of H sub(2)O sub(2) on production of dicarboxylic acid

• Published in: Biotechnology and bioengineering 2001-11, Vol.75 (4), p.456-462
• Main Authors: Jiao, Peng, Huang, Yingming, Li, Shuliang, Hua, Yutao, Cao, Zhu'an
• Format: Article
• Language: English
• ISSN: 0006-3592
• DOI: 10.1002/bit.10027

The system of producing long chain dicarboxylic acid (DCA) by Candida tropicalis is an aerobic and viscous fermentation system. A method to overcome the gas-liquid transport resistance and to increase oxygen supply is by adding hydrogen peroxide (H sub(2)O sub(2)) to the fermentation system. Here we report that the H sub(2)O sub(2) not only can enhance the oxygen supply but also change the metabolism by inducing cytochrome P450, the key enzyme of a, o-oxidation. When C. tropicalis was cultivated in a 3-L bioreactor using the combination of aeration and H sub(2)O sub(2) feeding, DCA production rates increased by about 10% after a short period of decrease at the beginning. Furthermore, the experiments showed that the maximum activities of P450 could be induced at 2 mM H sub(2)O sub(2), and the inducible mechanisms are also discussed. Moreover, we suggest that alkane might be oxidized through the "peroxide shunt pathway" when H sub(2)O sub(2) is present. By adding H sub(2)O sub(2), the DCA yield in a 22-L bioreactor could increase by 25.3% and reach 153.9 g/L.