Synthesis of cetyl ricinoleate in a solvent-free system via lipase-catalyzed esterification

Abstract: Wax esters with hydroxy fatty acid have been used for production of various value-added products, namely plasticizer, release agents, and surfactants. The wax esters are also widely used for the cosmetic ingredients in hair products, lipsticks, lotions, etc. In the present study, cetyl ricinoleate as a wax ester with hydroxy group was synthesized in solvent free system from ricinoleic acid and cetyl alcohol via lipase-catalyzed esterification. Four commercial lipases were screened for their ability to synthesis of cetyl ricinoleate. Three lipases, Lipozyme TL IM from Thermomyces lanuginosus, Lipozyme RM IM from Rhizomucor miehei, and Lipozyme 435 from Candida antarctica, showed similar activity in the synthesis of cetyl ricinoleate. However, Lipozyme TL IM was selected as a suitable biocatalyst due to the cost of enzyme. Temperature trials were carried out at above 50^oC because the melting point of cetyl alcohol used as substrate was 48^oC. The optimum temperature and enzyme loading were 50^oC, and 2%, respectively. The conversion of ca. 86% was obtained under the optimum conditions. In addition, we demonstrated that energy saving can be expected by step changes in temperature.