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.

Development of a promising microbial platform for the production of dicarboxylic acids from biorenewable resources

“…Only the POX1 gene—with a broad substrate spectrum—is expected to play an important role in fatty acid metabolism. An interesting phenomenon was reported previously, namely, that W. sorbophila simultaneously consumes various substrates during culture in the presence of mixed fatty acid methyl esters (C 10 –C 16 ) [ 12 ]. This may be associated with the broad substrate specificity of the product of the POX1 gene.…”

“…We previously isolated a novel alkane-assimilating yeast Wickerhamiella sorbophila from wastewater of a petrochemical factory and attempted to use it to produce DDDA using methyl laurate [ 12 ]. The growth of W. sorbophila strain capable of ω-oxidation in the presence of mixed fatty acid methyl esters (C 10 –C 16 ) was more stable than that of C. tropicalis and Yarrowia lipolytica [ 12 ]. Furthermore, it is a haploid and nonpathogenic yeast, with the associated advantages of genetic engineering and industrial safety [ 12 ].…”

“…The growth of W. sorbophila strain capable of ω-oxidation in the presence of mixed fatty acid methyl esters (C 10 –C 16 ) was more stable than that of C. tropicalis and Yarrowia lipolytica [ 12 ]. Furthermore, it is a haploid and nonpathogenic yeast, with the associated advantages of genetic engineering and industrial safety [ 12 ]. Recently, whole-genome sequencing of W. sorbophila was completed, allowing easy access to the genetic information ( https://www.ncbi.nlm.nih.gov/nuccore/NDIQ00000000.1/ ).…”

Advances in bio‐based production of dicarboxylic acids longer than C4

“…Typically, an exogenously applied fatty acid is imported and oxidized by P450 monooxygenase to the corresponding ω-hydroxy fatty acid. Several yeasts, such as Candida tropicalis, Candida sorbophila or Yarrowia lipolytica were reported to produce DCAs at industrially relevant levels by converting the corresponding fatty acids or alkanes [13][14][15][16]. When alkanes are used as substrates, they are initially converted to fatty acids with three oxidative reactions at the α position and the resulting fatty acids were further converted into DCAs via ω-oxidation [5].…”

“…When alkanes are used as substrates, they are initially converted to fatty acids with three oxidative reactions at the α position and the resulting fatty acids were further converted into DCAs via ω-oxidation [5]. Several yeasts, such as Candida tropicalis, Candida sorbophila or Yarrowia lipolytica were reported to produce DCAs at industrially relevant levels by converting the corresponding fatty acids or alkanes [13][14][15][16]. For example, engineered strains of C. tropicalis by amplifying the copies of P450 genes and blocking β-oxidation either partially or completely produced up to 50 g/L C6 DCA, 140 g/L C12 DCA, 210 g/L C14 DCA or 100 g/L C18 DCA from fatty acids or alkanes [15,17].…”