The effect of substrate concentrations on the production of biodiesel by lipase-catalysed transesterification of vegetable oils

All the kinetic studies, found in the literature, on the production of biodiesel (fatty acids methyl esters) considered the esterifications of free fatty acids rather than the transesterification of the vegetable oil itself. The main industrial interest, however, is for the production of biodiesel with the triglyceride (oil) being the substrate. A mathematical model taking into account the mechanism of the methanolysis reaction starting from the vegetable oil as substrate, rather than the free fatty acids, has been developed. From the proposed model equation, the regions where the effect of alcohol inhibition fades, at different substrate concentrations, were identified. The proposed model equation can be used to predict the rate of methanolysis of vegetable oils in a batch or a continuous reactor and to determine the optimal conditions for biodiesel production.