Microwave assisted lipase catalyzed synthesis of isoamyl myristate in solvent-free system

Abstract

► Lipase catalyzed solvent-free synthesis of isoamyl myristate. ► Novozyme 435 was found to be the best catalyst. ► Synergism of microwave irradiation with enzyme catalysis. ► Equimolar reactants, 0.38% (w/v) Novozym 435, 400 rpm, 60 °C, 1 h: 96% conversion. Isoamyl myristate finds many applications in food, cosmetic and pharmaceutical industries as a flavor and fragrance compound. The current work focuses on solvent-free lipase catalyzed microwave assisted synthesis of isoamyl myristate from isoamyl alcohol and myristic acid. The activities of a number of commercially available lipases such as Novozym 435, Lipozyme RM IM and Lipozyme TL IM were evaluated, amongst which Novozym 435 was found to be the most active. Effect of solvent, agitation speed, type of enzyme, enzyme concentration, reactant concentrations and temperature was systematically studied on the esterification of isoamyl alcohol with myristic acid under microwave irradiation. Equimolar quantities of the reactants with 0.38% (w/v) Novozym 435 catalyst loading and agitation speed of 400 rpm leads to 96% conversion at 60 °C in 1 h. Based on the initial rates and concentration profiles, the reaction was found to obey the ping-pong bi-bi mechanism with inhibition by isoamyl alcohol and the kinetic parameters were evaluated by using non-linear regression analysis.