Abstract
In recent years, the production of renewable fuels such as biodiesel has attracted considerable interest as an alternative to fossil fuels. The conventional alkalicatalyzed processes of biodiesel production present a number of drawbacks to which enzymatic processes present interesting solutions. Fungal lipases are among the most used biocatalysts in the enzymatic synthesis of biodiesel. Different strategies are currently under study in order to reduce the biocatalyst cost and to obtain a more robust biocatalyst with high activity and stability. This article reviews the status and possibilities for biodiesel production using fungal lipases, and discusses the critical aspects that influence lipase activity and stability, including choice of raw material and alcohols, type of biocatalyst, use of solvents, and water activity. Moreover, the development of whole-cells as a new promising technology, the exploration of alternative low-cost oils as potential feedstock and the evaluation of possible reactor configurations are also reported. In conclusion, considerations on the process and an economic efficacy analysis of industrial enzymatic biodiesel production are presented.
Keywords: Batch-Stirred-Tank Reactor, biocatalyst, biodiesel, esterification, ethanol, ethyl ester, free fatty acids, fungal lipases, glycerol, hydroesterification, immobilized lipase, methanol, methyl ester, microbial oil, Packed-Bed Reactor, transesterification, triglycerides, vegetable oils, waste oil, whole-cells.
