Developments in Biocatalytic Processes for Biodiesel Production

Abstract

Biodiesel production through transesterification is heavily reliant on catalysts, which play a significant role in the process. One of the major challenges in biodiesel production is selecting an appropriate catalyst. Both chemical and biological catalysts have been extensively researched for use in transesterification, each with its own set of advantages and disadvantages. Biocatalysts, particularly enzymes, have several desirable qualities that make them superior to chemical catalysts. These qualities include homogeneity, biocompatibility, biodegradability, and environmental acceptability. Lipases and phospholipases, with their specificity and regio- and enantioselectivity, are particularly useful in promoting the esterification and transesterification of carboxylic esters during biodiesel production. However, despite these benefits, the high cost of enzymes and the need for recycling contribute to higher production costs. Whole cell-based catalysts derived from various microbes have lower efficiency in the presence of an oily substrate, which reduces the biodiesel yield. However, immobilizing enzymes on a solid matrix has shown promise in improving enzyme stability, reusability, and the ability to survive in extreme temperature and pH environments. Several immobilization methods are available, such as physical adsorption, covalent bonding, entrapment, encapsulation, and cross-linking. It is worth exploring the interactions between biocatalysts and carriers, and also attempting to enhance enzyme features through immobilization or co-immobilization, and the use of whole cells to produce biodiesel more efficiently.