Optimal pH control strategy for high-level production of long-chain α,ω-dicarboxylic acid by Candida tropicalis

• Published in: Enzyme and microbial technology 2004-01, Vol.34 (1), p.73-77
• Main Authors: Liu, Shuchen, Li, Chun, Fang, Xiangchen, Cao, Zhu’an
• Format: Article
• Language: English
• Subjects: a,^w-dicarboxylic acids; Biological and medical sciences; Biotechnology; Candida tropicalis; cytochrome P450 monooxygenase; dioic acid; dodecane; Fundamental and applied biological sciences. Psychology; Methods. Procedures. Technologies; Microbial engineering. Fermentation and microbial culture technology; Optimal strategy; tetradecane; α,ω-Dicarboxylic acid
• ISSN: 0141-0229; 1879-0909
• DOI: 10.1016/j.enzmictec.2003.09.001

A mutant of Candida tropicalis was used to convert n-alkanes to the corresponding α,ω-dicarboxylic acids (DC). Effects of medium pH on dioic acid productions were studied in batch fermentations in which growth and conversion were separated into a growth and a conversion phase. A pH control strategy for the high-level production of α,ω-tridecanedioic acid has been proposed and optimized, i.e. programmed incremental pH increase from pH 7.2 to 8.10 during DC production stage, the dioic acid concentration reached 153 g/l after 120 h transformation and demonstrated a 22% increase in production compared to that obtained with an optimized constant pH value. Using the optimal strategy for n-dodecane and n-tetradecane fermentation, the corresponding dioic acid concentrations reached 166 and 138 g/l, respectively. The influences of the strategy on cytochrome P450 monooxygenase activity of the cells were also examined; the maximum activity of the enzyme can be maintained for a longer period of time during the conversion phase using by this optimal strategy.