Optimization of Enzymatic Synthesis of Cetyl 2‐Ethylhexanoate by Novozym® 435

Abstract Waxes are esters obtained from long‐chain fatty acids and long‐chain alcohols which are biodegradable, biocompatible and nontoxic. Seafowl feather oil is a natural wax ester that exists on seafowl feathers. Cetyl 2‐ethylhexanoate is the major ingredient of seafowl feather oil. Cetyl 2‐ethylhexanoate is widely used in cosmetics as a base oil because of its lubricity, moisture retention and non‐toxic properties. An optimal production of cetyl 2‐ethylhexanoate by direct esterification of cetyl alcohol with 2‐ethylhexanoic acid was developed using an immobilized lipase (Novozym ® 435) as a catalyst in n ‐hexane. Response surface methodology (RSM) and 5‐level‐4‐factor central composite rotatable design (CCRD) were employed to evaluate the effects of reaction time, reaction temperature, substrate molar ratio, and enzyme amount on the yield of cetyl 2‐ethylhexanoate. The results show that reaction time, reaction temperature, substrate molar ratio, and enzyme amount have significant effects on the yield of the esterification reaction. On the basis of ridge‐max analysis, the optimum conditions were as follows: a reaction time of 2.65 days, a reaction temperature of 56.18 °C, a substrate molar ratio of 2.55:1, and an enzyme amount of 251.39%. The predicted and experimental values of molar conversion were 91.95 and 89.75 ± 1.06%, respectively.