This study aimed at the development of biotransformation strategies with feeding of energy sources for bioconversion of ricinoleic acid to (E)-11-(heptanoyloxy) undec-9-enoic acid (11-HOUA), a key intermediate of brassylic acid, by recombinant Escherichia coli overexpressing an alcohol dehydrogenase from Micrococcus luteus and a Baeyer-Villiger monooxygenase from Pseudomonas putida KT2440. Feeding of glucose or glycerol facilitated both the preparation of high-density cell biocatalyst and supply of the NAD+ and NADPH cofactors. By the glucose feeding strategy, 30.8g/L of the engineered E. coli cells produced 29.7mM of 11-HOUA with 1.9mM/h of productivity, which were 1.8 and 1.6 times higher than the same biotransformation without the glucose feeding, respectively. Intermittent addition of glycerol increased 11-HOUA productivity by 16% compared to that by the glucose feeding. Finally, 34.5mM of 11-HOUA concentration, 77% conversion and 2.2mM/h productivity were obtained using 31.6g/L of cell biocatalyst along with the glycerol addition. It was concluded that supplementation of additional carbon sources in biotransformation process would be a potent strategy to increase the performance of fatty acid conversion.
Keywords: (E)-11-(Heptanoyloxy) undec-9-enoic acid; Alcohol dehydrogenase; Baeyer-Villiger monooxygenase; Fed-batch; Recombinant Escherichia coli; Ricinoleic acid.
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