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Enantiodifferentiation of four γ‐lactones produced by Penicillium Roqueforti
Author(s) -
Chalier Pascale,
Crouzet Jean
Publication year - 1998
Publication title -
chirality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.43
H-Index - 77
eISSN - 1520-636X
pISSN - 0899-0042
DOI - 10.1002/(sici)1520-636x(1998)10:9<786::aid-chir2>3.0.co;2-8
Subject(s) - chemistry , penicillium roqueforti , enantiomer , enantiomeric excess , lipase , organic chemistry , linoleic acid , stereochemistry , gas chromatography , lactone , stereoselectivity , chromatography , fatty acid , penicillium , enzyme , enantioselective synthesis , catalysis , food science
Identification and enantiodifferentiation of γ‐lactones produced during the bioconversion of soy bean fatty acids by Penicillium roqueforti spores in the presence of an exogenous lipase was performed using gas chromatography‐mass spectrometry (GC‐MS) in selected ion monitoring (SIM) mode. It was shown that 4‐dodecanolide and 4‐hexanolide were first produced with an enantiomeric excess (99%) in favor of the (R) form, whereas an enantiomeric excess in favor of the (S) form (94%) is found for (6Z)‐dodecen‐4‐olide, the major lactone produced by the fungus. If incubation was continued, mixtures of both enantiomers were found, more particularly for 4‐decanolide (R/S:40/60), which was produced only after 120 hr of incubation. The results obtained can be explained by the stereoselective hydroxylation by a 10‐hydratase and/or a 10‐lipoxygenase of the unsaturated fatty acid precursors, oleic and linoleic acids, and by competition between different pathways. The results point out the limitations of chiral GC analysis as a criterion for the natural origin of relevant lactones, and the complexity of mechanisms involved in γ‐lactone formation by microorganisms. Chirality 10:786–790, 1998. © 1998 Wiley‐Liss, Inc.