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

摘要

The biosyntheses of aroma active - and -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-~(13)C_1)decanoate ((~(13)C)-1b) and methyl (±)-4-hydroxy(1-~(13)C_1)decanoate ((~(13)C)-7a). Aliquots of the culture broth were analyzed with GC/MS after CH_2N_2 derivatization. S. odorus degraded (~(13)C)-1b to 5-oxo(1-13C1)decanoic acid ((~(13)C)-2c) and, subsequently, to pentyl (1-13C1)pentanedioate ((~(13)C)-3c) and 3-[(1-~(13)C_1)carboxypropyl] hexanoate ((~(13)C)-4c) by a BaeyerVilliger-type oxidation (BVO). In addition, the oxidation of (~(13)C)-7a to 4-oxo(1-13C1)decanoic acid ((~(13)C)-8c) and a BVO of (~(13)C)-8c to hexyl (1-~(13)C_1)butanedioate ((~(13)C)-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.