Abstract

Although fossil fuels have been serving mankind for several centuries, their exploration and use bring about several environmental problems. Besides, fossil fuels are neither renewable nor sustainable. There is therefore a need to search for renewable alternatives which are sustainable and environmentally friendly. Biodiesel, chemically known as methyl ester, is a renewable and sustainable biofuel used to run diesel engines and it is mainly produced by transesterification through either chemical or enzymatic catalysis. Enzyme catalyzed transesterification has several advantages over chemical catalysis. However, enzyme production and purification are expensive and the inability to recycle these enzymes has limited their application in large scale bioconversion processes. This review highlights some of the strategies employed to reduce the cost of lipase catalzsed transesterificaion, some important feed stocks used in biodiesel production, methods of processing biodiesel, and advantages of enzymatic transesterification over chemical catalyzed transesterification. The properties and sources of lipase enzymes used in enzyme catalyzed transesterfication are also highlighted and discussed. Factors that affect enzyme catalyzed transesterification are also discussed. It also highlights the possible methods of solving the problems encountered in enzymatic transesterification.

Key words: Biodiesel, transesterification, lipase, enzymes, catalysis, immobilization.