Simultaneous Enzyme/Whole-Cell Biotransformation of C18 Ricinoleic Acid into (R)-3-Hydroxynonanoic Acid, 9-Hydroxynonanoic Acid, and 1,9-Nonanedioic Acid

Regiospecific oxyfunctionalization of renewable long chain fatty acids into industrially relevant C9 carboxylic acids has been investigated. One example was biocatalytic transformation of 10,12-dihydroxyoctadecanoic acid, which was produced from ricinoleic acid ((9Z,12R)-12-hydroxyoctadec-9-enoic acid) by a fatty acid double bond hydratase, into (R)-3-hydroxynonanoic acid, 9-hydroxynonanoic acid, and 1,9-nonanedioic acid with a high conversion yield of ca. 70%. The biotransformation was driven by enzyme/whole-cell biocatalysts, consisting of the esterase of Pseudomonas fluorescens and the recombinant Escherichia coli expressing the secondary alcohol dehydrogenase of Micrococcus luteus, the Baeyer-Villiger monooxygenase of Pseudomonas putida KT2440 and the primary alcohol/aldehyde dehydrogenases of Acinetobacter sp. NCIMB9871. The high conversion yields and the high product formation rates over 20 U/g dry cells with insoluble reactants indicated that various (poly-hydroxy) fatty acids could be converted into multi-functional products via the simultaneous enzyme/whole-cell biotransformations. This study will contribute to the enzyme-based functionalization of hydrophobic substances.