Characterization of the newly isolated ω-oxidizing yeast Candida sorbophila DS02 and its potential applications in long-chain dicarboxylic acid production

Abstract

α, ω-Dicarboxylic acids (DCAs) are multipurpose chemicals widely used in polymers, perfumes, plasticizers, lubricants, and adhesives. The biotransformation of DCAs from alkanes and fatty acids by microorganisms has attracted recent interest, since synthesis via chemical oxidation causes problems in terms of the environment and safety. We isolated an ω-oxidizing yeast from a wastewater disposal facility of a petrochemical factory by chemostat enrichment culture. The haploid strain identified as Candida sorbophila DS02 grew on glucose and dodecane, exhibiting greater cell shrinkage on the latter. In flask cultures with mixed alkanes (C10-16) and fatty acid methyl esters (C10-16), DS02 used mixed alkanes simultaneously unlike Candida tropicalis and Yarrowia lipolytica and showed high substrate resistance. In flask cultures with acrylic acid-a known inhibitor of β-oxidation-DS02 produced 0.28 g/l dodecanedioic acid (DDDA) from dodecane, similar to wild-type C. tropicalis ATCC 20336. In fed-batch fermentation, DS02 produced 9.87 g/l DDDA, which was 5.7-fold higher than wild-type C. tropicalis. These results suggest that C. sorbophila strain DS02 has potential applications for the large-scale production of DCA