Production of ω-hydroxyundec-9-enoic acid and n-heptanoic acid from ricinoleic acid by recombinant Escherichia coli-based biocatalyst

Abstract ω-Hydroxyundec-9-enoic acid and n -heptanoic acid are valuable building blocks for the production of flavors and antifungal agents as well as bioplastics such as polyamides and polyesters. However, a biosynthetic process to allow high productivity and product yield has not been reported. In the present study, we engineered an Escherichia coli -based biocatalytic process to efficiently produce ω-hydroxyundec-9-enoic acid and n -heptanoic acid from a renewable fatty acid (i.e., ricinoleic acid). Expression systems for catalytic enzymes (i.e., an alcohol dehydrogenase of Micrococcus luteus , a Baeyer–Villiger monooxygenase of Pseudomonas putida KT2440, an esterase of Pseudomonas fluorescens SIK WI) and biotransformation conditions were investigated. Biotransformation during stationary growth phase of recombinant E. coli in a bioreactor allowed to produce ω-hydroxyundec-9-enoic acid and n -heptanoic acid at a rate of 3.2 mM/h resulting in a final product concentration of ca. 20 mM. The total amount of ω-hydroxyundec-9-enoic acid and n -heptanoic acid produced reached 6.5 g/L (4.0 g/L of ω-hydroxyundec-9-enoic acid and 2.5 g/L of n -heptanoic acid). These results indicate that the high value carboxylic acids ω-hydroxyundec-9-enoic acid and n -heptanoic acid can be produced from a renewable fatty acid via whole-cell biotransformation.