Continuous operation of alcohol dehydrogenase (ADH) catalysed enantioselective reduction in a biphasic sytem showed gains in productivity and stability of the overall reaction system. The total turnover numbers obtained for the cofactor NADP + are high with up to 1.5 10 4. Productivity for (R)-2-butanol with Lactobacillus brevis ADH was up to 26 kmol (mol enzyme) 1. Enantioselectivity was greater than 0.99 for (R)-phenylethanol and up to 0.99 for (R)-butanol.