DefinePK

Abstract

Currently, the enzymatic production of biodiesel has drawn considerable attention. But, it still cannot apply to commercial industry because the cost of enzyme providing is high due to the decreasing of enzyme activity and stability in reaction. So, it cannot be reused. The advantage of enzymatic process is high-purity products because it is easy in removing by-products such as glycerol. But, there is possibility that enzyme activity and stability decrease because of inactivation by acyl acceptors and impurities in oils or by-products, glycerol. Choline-based ionic liquids used as a solvent supposed to decrease inactivation because it is greener than organic solvents and non-volatile. This study used palm oil, ethanol used as an acyl acceptor because it is more renewable than methanol, Novozym® 435, and ChCl as a solvent. The reaction parameters that used in this research were the temperature reaction, reaction time, and ChCl dosage. This study showed that yield biodiesel in ChCl system was lower compared to ChCl-free system for a single use. But, it could obtain the highest yield when enzyme was reused for several times. The highest yield of 99.50 % was obtained in third reuse of enzyme at molar ratio of 1:6, temperature of 40ºC, reaction time of 7 hours and 0.5 % of ChCl. The decreasing of yield biodiesel occurred when ChCl concentration was increased. This result also showed that time reaction gave an effect to ethyl ester yield between in ChCl system and ChCl-free system. Based on the results, it shows that the characteristic of ionic liquids influences enzyme activity in reaction which can decrease or increase it. So, it needs to do further research about choline-based ionic liquids to increase enzyme activity.