AbstractThe activity of purifiedPseudomonas cepacialipase has been investigated in esterification reactions of various aliphatic alcohols with natural fatty acids. The reactions were carried out in microemulsions formed in isooctane by bis‐(2‐ethylhexyl)sulfosuccinate sodium salt (AOT). Kinetic studies showed that the reaction follows a ping‐pong bi–bi mechanism with inhibition by both substrates. The apparent kinetic parameters of the reaction were found to beKmoctanol= 310 mM,Kmlauric acid= 78 mM, andVmax= 250 μmol min−1mg−1. The same system was used for the synthesis of mono‐ and diglycerides from glycerol and lauric acid, which was successful at very lowwovalues. The catalytic behavior ofP. cepacialipase was also studied in esterification reactions performed in a nonionic microemulsion system formulated by tetraethyleneglycoldodecylether (C12E4). The optimum activity was found at aboutwo= 8. The apparent values ofVmax appandKm appfor octanol were calculated and found to be 100 μmol min−1mg−1and 76 mM, respectively. © 1995