Lipase Catalyzed Transesterification of Tung and Palm Oil for Biodiesel

Abstract

The tung oil and palm oil were subjected to enzymatic transesterification. Immobilized lipase (Novozyme 435) was used at 10 % w/v vs. oil. The reactions were conducted at 40C to 60C with methanol and ethanol at a molar ratio of 1:3 for 24 h ours. Temperature was found critical for the conversion efficiencies. Under 55C after 24 hour, the optimal conversions of tung oil and palm oil fatty acid methyl esters (FAMEs) were 48 % and 63 %. The optimal conversions for tung oil and palm oil fatty acid ethyl esters (FAEEs) at 50C were 20 % and 55 % respectively at 50C. It was found the effciencies of FAEEs conversion were lower than the ones of FAMEs conversion. It was found that the tung oil consisted of 80 % unsaturated fatty acids, and palm oil consisted by just over 50% saturated fatty acids, by contrast. The results showed that the fatty acid composition of oil could directly impact on the efficiencies of enzymatic transesterification. A numerical model was derived to describe the reaction in this two-phase system. It was found that fitted mass transfer coefficients and rate constants of the pseudo-steady-state second order reaction were consistent to experimental results.