Biodiesel as renewable biofuel produced via enzyme-based catalyzed transesterification

Biodiesel is a renewable alternative biofuel to conventional fossil fuel. Biodiesel can be produced through esterification and transesterification reactions mainly catalyzed by acid, alkali, and enzyme catalysts. Among all of these catalysts, enzyme catalysts are more advantageous than chemical catalysts (alkali and acid catalysts) due to their high selectivity, mild reaction conditions, lower energy consumption, and yielding of good quality of products with no side reactions. However, because of the high costs of enzymes, there is a limit on the use of enzymatic operation on an industrial scale. The cost of enzymes can be reduced by improving the lifespan of catalysts. Over the last few decades, significant developments in enzyme-based biodiesel synthesis have been attained both on the laboratory and industrial scale, and production costs are also reduced. This review gives an overview of immobilized lipase-catalyzed and lipase-inorganic hybrid nanoflowers catalyzed biodiesel production, including the economic viability of enzyme catalysts and idea about different reactors which is used for enzymatic transesterification reaction.