Chemo-enzymatic synthesis of 11-hydroxyundecanoic acid and 1,11-undecanedioic acid from ricinoleic acid

Abstract

A practical chemoenzymatic synthetic method for 11-hydroxyundecanoic acid and 1,11-undecanedioic acid from ricinoleic acid (12-hydroxyoleic acid) was investigated. Biotransformation of ricinoleic acid into the ester (3) via 12-ketooleic acid (2) was driven by recombinant Escherichia coli cells expressing an alcohol dehydrogenase from Micrococcus luteus and the Baeyer-Villiger monooxygenase from Pseudomonas putida KT2440. The carbon-carbon double bond of the ester (3) was chemically reduced, and the ester bond was hydrolyzed to afford n-heptanoic acid (5) and 11-hydroxyundecanoic acid (7), which were converted into other related derivatives. For example, 11-hydroxyundecanoic acid was transformed into 1,11-undecanedioic acid (8) under fairly mild reaction conditions. Whole-cell biotransformation at high cell density (i.e., 20 g dry cells per L) allowed the final ester product concentration and volumetric productivity to reach 53 mM and 6.6 mM h(-1), respectively. The overall molar yield of 1,11-undecanedioic acid from ricinoleic acid was 55% based on the biotransformation and chemical transformation conversion yields of 84% and 65%, respectively.