Biocatalysis using oxygenase or desaturase enzymes has the potential to add
value to native fats and oils by adding oxygen, hydroxyl groups, or double
bonds to create regio- and/or stereospecific products. These enzymes are a
subset of the large class of oxidoreductase enzymes (from EC subgroups 1.1
3 and 1.14) involved with biological oxidation and reduction. In vitro bioc
atalytic processing using these enzymes is hampered by the high cost of the
stoichiometric cofactors. This article reviews recent progress in developi
ng in vitro redox enzyme biocatalysis for commercial-scale syntheses. Coenz
yme recycling and electrochemical redox cycling as methods for cofactor reg
eneration are described and commercial applications indicated. Direct charg
e transfer without use of mediators is described as the cleanest way of int
roducing the reducing power into the catalytic cycle. Our electrochemically
driven cytochrome P450(cam) bioreactor is discussed as an example of direc
t charge transfer to a redox protein. Site-directed mutagenesis in the acti
ve site of the P450(cam) monooxygenase greatly improved performance for the
conversion of the nonnative substrate, styrene to styrene oxide. This epox
idation reaction was also shown to give a single product (styrene oxide) in
the bioelectrochemical reactor when the diatomic oxygen co-substrate was m
anaged properly.