Process Biochemistry, Vol.45, No.8, 1268-1273, 2010
Two step ethanolysis: A simple and efficient way to improve the enzymatic biodiesel synthesis catalyzed by an immobilized-stabilized lipase from Thermomyces lanuginosus
In this study the immobilization and stabilization of a lipase from Thermomyces lanuginosus (TLL) on aldehyde-Lewatit (Lew-TLL) are described. TLL immobilization was rapid and over 90% of lipase activity was recovered after the immobilization. Lew-TLL was 10-fold more thermo stable than the commercial TLL preparation, Lipozyme TL-IM. The stabilized Lew-TLL was used for the enzymatic transesterification of ethanol and soybean oil. The transesterification was carried out following different strategies. First, with 7.5:1 molar ratio of ethanol:soybean oil, 15% immobilized enzyme and 4% water at 30 degrees C. In the presence of n-hexane, the transesterification reached 100% conversion, while in solvent-free system the yield was 75%. Second, at stoichiometric molar ratio, the yield was 70% conversion after 10 h of reaction in both systems. After this, transesterification was carried out by three stepwise additions of ethanol with a yield of 80% conversion, while a two step ethanolysis produced 100% conversion after 10 h of reaction in both solvent and solvent-free systems. (C) 2010 Elsevier Ltd. All rights reserved.
Keywords:Biodiesel;Thermomyces lanuginosus lipase;Multipoint covalent attachment;Ethanolysis;Soybean oil