Candida rugosa lipase was immobilized in gelatin containing Aerosol-OT (AOT) microemulsion-based organogels (MBGs) and on silica gel. The highest condensation activity on n-caprylic acid with ethanol was observed at R = 60. Selective removal of water was achieved using 1 M AOT in isooctane dry reverse micelles for MBG with R = 70. This pretreatment of lipase containing MBG resulted in the enhanced esterification. Lipase containing MBG proves a better immobilization system than lipase on silica gel. (C) 2001 Elsevier Science Ltd. All rights reserved.