Esterification kinetics of long-chain fatty acids and fatty alcohols with a surfactant-coated lipase in n-hexane

The esterification reaction kinetics of long-chain fatty acids and fatty alcohols catalyzed with a surfactant-coated lipase in a microaqueous n-hexane system were studied. The biocatalytic complex, surfactant-lipase adduct, showed 40 times the activity after a reaction time of 5 h compared to the unmodified lipase in the same reaction system. Various factors that may affect the activity of the modified lipase were studied; such as the influence of substrate fatty acid chainlength, water content, and temperature. By varying the concentration of each of the two substrates while keeping that of the other substrate constant, it was found hat the esterification reaction follows Michaelis-Menten kinetics. The surfactant-enzyme complex kinetic parameters were determined with respect to both substrates. It was suggested that the kinetics of the lipase-catalyzed esterification reaction model follow a Ping-Pong Bi Bi mechanism with no substrate or product inhibition.