The use of dry mycelium of Rhizopus oryzae as biocatalyst for ester production in organic solvent has been studied. Mycelia with notable carboxylesterase activity were produced when different Tweens (20, 40, 60 and 80) were employed as main carbon source for the growth. Dry mycelium of four strains of Rhizopus oryzae proved effective for efficiently catalysing the synthesis of different flavour esters (hexylacetate and butyrate, geranylacetate and butyrate) starting from the corresponding alcohol and free acid, including acetic acid. The esterification of the racemic mixture of 2-octanol and butyric acid proceeded with high enantioselectivity (R-ester produced with enantiomeric excess > or =97%) when Rhizopus oryzae CBS 112.07 and Rhizopus oryzae CBS 260.28 were employed.