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Role of beta-oxidation enzymes in gamma-decalactone production by the yeast Yarrowia lipolytica

Wache, Y., Aguedo, M., Choquet, A., Gatfield, I.L., Nicaud, J.M., Belin, J.M.
Applied and environmental microbiology 2001 v.67 no.12 pp. 5700-5704
biosynthesis, lactones, Yarrowia lipolytica, oxidoreductases, mutants, odors, oleic acid, enzyme activity
Some microorganisms can transform methyl ricinoleate into gamma-decalactone, a valuable aroma compound, but yields of the bioconversion are low due to (i) incomplete conversion of ricinoleate (C18) to the C10 precursor of gamma-decalactone, (ii) accumulation of other lactones (3-hydroxy-gamma-decalactone and 2- and 3-decen-4-olide), and (iii) gamma-decalactone reconsumption. We evaluated acyl coenzyme A (acyl-CoA) oxidase activity (encoded by the POX1 through POX5 genes) in Yarrowia lipolytica in lactone accumulation and gamma-decalactone reconsumption in POX mutants. Mutants with no acyl-CoA oxidase activity could not reconsume gamma-decalactone, and mutants with a disruption of pox3, which encodes the short-chain acyl-CoA oxidase, reconsumed it more slowly. 3-Hydroxy-gamma-decalactone accumulation during transformation of methyl ricinoleate suggests that, in wild-type strains, beta-oxidation is controlled by 3-hydroxyacyl-CoA dehydrogenase. In mutants with low acyl-CoA oxidase activity, however, the acyl-CoA oxidase controls the beta-oxidation flux. We also identified mutant strains that produced 26 times more gamma-decalactone than the wild-type parents.