No abstract

Biodiesel has been receiving significant attention as a renewable and nonpolluting fuel. In this study, oleic acid and bioalcohols (ethanol and butanol) were used as substrates for biodiesel production. The reactions were performed in a solvent-free system using immobilized lipase (Novozym 435) as biocatalyst in a batch esterification process. The optimal conditions were 45°C, oleic acid to alcohol molar ratio of 1:2, Novozym 435 loading at 5% based on oleic acid weight and 250 rpm, in which the free fatty acid (FFA) conversion at 91.0% was obtained after 12 hours of the reaction.

Recently, demand of biolubricants has been continuously increased since it is environmentally friendly and renewable. Therefore, this research focused on the biolubricants production from enzymatic esterification of oleic acid and propanol using Novozym 435 as a biocatalyst. The esterification experiments were conducted under the optimal conditions, as follows: 45°C, oleic acid to propanol molar ratio of 1:2, Novozym 435 loading of 5% based on the weight of oleic acid. It was shown that the optimal rotation speed at 250 rpm could minimize the effect of external mass transfer limitations and maintained the enzyme activity. The conversion of oleic acid from the esterification for 6 h with isopropanol was 76.4%, which was lower than that with n-propanol (88.9%). Novozym 435 could be reused in the production of propyloleate for at least 5 cycles with maintaining FFA conversion of 94% of its initial value. Moreover, the use of molecular sieve to remove water during the reaction could significantly enhance the final FFA conversion from 88.9% to 94.7%.