Enzymatic Baeyer–Villiger Oxidation as the Key Step in Decano‐4‐lactone and Decano‐5‐lactone Degradation by Sporobolomyces odorus

AbstractThe biosyntheses of aroma active γ‐ and δ‐lactones have been previously characterized in yeasts and plants by incubation of labeled fatty acid derivatives. The lactones were considered as end products. Liquid cultures of the lactone‐producing yeast Sporobolomyces odorus were used to investigate catabolic pathways of the lactones by incubation of ethyl (±)‐5‐hydroxy(1‐13C1)decanoate ((13C)‐1b) and methyl (±)‐4‐hydroxy(1‐13C1)decanoate ((13C)‐7a). Aliquots of the culture broth were analyzed with GC/MS after CH2N2 derivatization. S. odorus degraded (13C)‐1b to 5‐oxo(1‐13C1)decanoic acid ((13C)‐2c) and, subsequently, to pentyl (1‐13C1)pentanedioate ((13C)‐3c) and 3‐[(1‐13C1)carboxypropyl] hexanoate ((13C)‐4c) by a BaeyerVilliger‐type oxidation (BVO). In addition, the oxidation of (13C)‐7a to 4‐oxo(1‐13C1)decanoic acid ((13C)‐8c) and a BVO of (13C)‐8c to hexyl (1‐13C1)butanedioate ((13C)‐9c) is reported. So far, BVO has been observed in bacteria and some fungi; the data presented indicate a BVO catalyzed by the yeast S. odorus in the course of endogenous lactone metabolism.