Biosynthesis of ω-hydroxyundec-9-enoic acid from ricinoleic acid in recombinant Escherichia coli

ω-Hydroxyundec-9-enoic acid is a valuable chemical as an antifungal substance and a precursor for production of bioplastics. In order to produce (E)-11-(heptanoyloxy) undec-9-enoic acid, a key intermediate of ω-hydroxyundec-9-enoic acid from renewable fatty acid (e.g., ricinoleic acid), we overexpressed alcohol dehydrogenase from Micrococcus luteus and a Baeyer-Villiger monooxygenase from Pseudomonas putida in Escherichia coli. In a high cell density fed-batch fermentation with a continuous glucose-feeding strategy, the engineered E. coli produced (E)-11-(heptanoyloxy) undec-9-enoic acid from ricinoleic acid with 81 % (w/w) of conversion yield from ricinoleic acid and 1.6 g/L-h of productivity. Additionally, we introduced an esterase gene derived from Pseudomonas fluorescens SIK WI to convert (E)-11-(heptanoyloxy) undec-9-enoic acid into ω-hydroxyundec-9-enoic acid. The resulting strain produced ω-hydroxyundec-9-enoic acid from ricinoleic acid with 20 % of conversion yield and 0.2 g/L-h of productivity. These results suggested that E. coli might be a potent host strain to produce ω-hydroxyundec-9-enoic acid from ricinoleic acid in caster oil.