The effect of solvent, operating temperature, enzyme concentration and immobilization on activity and enantioselectivity of a Candida rugosa lipase for the kinetic resolution of +/-2-(4-chlorophenoxy) propionic acid with 1-butanol in organic solvents was studied. The crude enzyme powder gave more than 50% conversion and with an enantiomeric excess (ee) of 100% for the remaining S-acid at 40 degreesC with carbon tetrachloride as the solvent. Higher enantioselectivities were obtained when the reactions were performed at temperatures between 30 and 40 degreesC and at lower water activities, a(w). Immobilization of the lipase onto various types of support results in loss of activity and selectivity. The best results was obtained with the enzyme preparation immobilized onto silica gel. This gave 33% overall conversion and an ee of 46% for the S-acid. Continuous resolution process via a packed bed reactor resulted in an overall conversion of around 50 and 100% ee for the S enantiomer. (C) 2003 Elsevier Science Ltd. All rights reserved.