Are plant lipases a promising alternative to catalyze transesterification for biodiesel production?

Interest in the production of biodiesel—a clean renewable fuel—is increasing worldwide. Industrial-scale processes currently being developed use homogenous and heterogeneous chemical catalysis processes that are highly efficient but require very pure reagents and complex product purification steps, or high temperature and pressure processing conditions. Enzymatic catalysis using plant lipases as biocatalysts is an alternative which, contrary to chemical catalysis processes, is simple to perform, at low investment cost, and therefore potentially easier to disseminate, especially in developing countries. Although microbial lipases have been extensively studied, little research has been focused on the use of plant lipases in biodiesel production. These latter lipases can, however, be readily extracted from the plant organs that contain them (seeds, bran or latex) and they are less expensive to use than microbial lipases. The aim of the present article was thus to review published research findings and outline the most advanced knowledge concerning alkyl ester production catalyzed by plant lipases. This work focuses mainly on the conditions for using plant lipases in certain synthesis reactions (biomass selection, preparation and purification of lipase extracts) and current knowledge on reaction parameters that affect the catalytic activity. Moreover, biodiesel production using plant lipases and ethanol instead of methanol certainly seems to be in line with the development of innovative environment-friendly technologies.