Method for stereoselectively preparing a (R) or (S) gamma-lactone consists
in microbially biosynthesising gamma-lactone, wherein the biosynthesis is
carried out from a substrate selected from C5 to C20 fatty acids with the
aid of a strain selected from those enabling a stereoselective
hydroxylation in C4 of the substrate, in particular Aspergollus sp or
Mortierella sp. The biosynthesis of the gamma-lactone and the use thereof
in perfumery and for food flavouring agents are also disclosed.