Enzymatic reduction of ketones in "micro-aqueous" media catalyzed by ADH-A from Rhodococcus ruber.

Mono- and biphasic aqueous-organic solvent systems (50% v v-1) as well as micro-aqueous organic systems (99% v v-1) were successfully employed for the biocatalytic reduction of ketones catalyzed by alcohol dehydrogenase ADH-A from Rhodococcus ruber via hydrogen transfer. A clear correlation between the log P of the organic solvent and the enzyme activity--the higher, the better--was found. The use of organic solvents allowed highly stereoselective enzymatic carbonyl reductions at substrate concentrations close to 2.0 M.