Catalytic studies of lipase on FAME production from waste cooking palm oil in a tert-butanol system

In this present work, fatty acid methyl ester (FAME) was produced from waste cooking palm oil (WCPO) by lipase-catalyzed reaction. The catalytic activities of several commercial lipases and different organic solvent were screened. Novozyme 435 was found to be more effective in catalyzing the transesterification of WCPO with methanol. tert-Butanol was used as the reaction medium, which eliminated both negative effect caused by excessive methanol and glycerol as the byproduct. Several variables such as effect of methanol/oil molar ratio, effect of lipase quantity and effect of agitation speed (rpm) were examined in a batch system. Transesterification of WCPO can reach up to 88% FAME yield under optimum condition (methanol/oil molar ratio 4:1, 4% Novozyme 435 based on oil weight, 200 rpm and 12 h reaction time). Kinetics of lipase-catalyzed transesterification of WCPO in tert-butanol system was also investigated. A model based on Ping Pong Bi Bi with only inhibition by methanol was found to fit the initial rate data and the kinetics parameters were evaluated by non-linear regression analysis.