Lipase-catalyzed transesterification of rapeseed oils for biodiesel production with a novel organic solvent as the reaction medium

tert-Butanol, as a novel reaction medium, has been adopted for lipase-catalyzed transesterification of rapeseed oil for biodiesel production, with which both the negative effects caused by excessive methanol and by-product glycerol could be eliminated. Combined use of Lipozyme TL IM and Novozym 435 was proposed further to catalyze the methanolysis and the highest biodiesel yield of 95% could be achieved under the optimum conditions (tert-butanol/oil volume ratio 1:1; methanol/oil molar ratio 4:1; 3% Lipozyme TL IM and 1% Novozym 435 based on the oil weight; temperature 35 degrees C; 130 rpm, 12 h). There was no obvious loss in lipase activity even after being repeatedly used for 200 cycles with tert-butanol as the reaction medium. Furthermore, waste oil was also explored for biodiesel production and it has been found that lipase also showed good stability in this novel system. (c) 2006 Elsevier B.V. All rights reserved.