Kinetics of enzymatic esterification of glycerol and free fatty acids in crude Jatropha oil by immobilized lipase from Rhizomucor miehei

Enzymatic neutralization is a recent research focus due to an increasing awareness of environmental problems caused by conventional oil refining. This study investigated the kinetics of enzymatic neutralization in crude Jatropha oil utilizing an immobilized lipase from Rhizomucor miehei. Free fatty acids, in particular oleic acid were esterified with glycerol. The reaction seems to follow a multisubstrate Ping Pong mechanism with competitive inhibition by the acyl acceptors (mono-, diacylglycerides and glycerol). Free fatty acid content did not affect lipase activity within the ranges investigated. The kinetic parameters were determined and showed that enzyme affinity is much higher to glycerol than to free fatty acids. These observations were supported by the fact that the optimum glycerol level is rather small while the reaction rate increases with increasing free fatty acid concentration.