Stereoselective Reduction of Carbonyl Compounds Using the Cell-Free Extract of the Earthworm, Lumbricus rubellus, as a Novel Source of Biocatalyst

Abstract

We found the reducing activity toward carbonyl compounds in the cell-free extract of the earthworm, Lumbricus rubellus. The earthworm extract had a reducing activity for keto esters in the presence of NADH or NADPH as a coenzyme. The earthworm extract reduced ethyl 3-methyl-2-oxobutanoate to the corresponding alcohol with a high enantiomeric excess (91%, R-form) at 50 °C in the presence of NADH. In particular, ethyl 2-oxoheptanoate was exclusively reduced to the corresponding (R)-hydroxyl ester with a high enantiomeric excess (>99%).