Emerging technologies for biodiesel production: Processes, challenges, and opportunities

Fossil fuel shortages, rising petroleum prices, worldwide demand for renewable energy, and greenhouse gas (GHG) emissions due to anthropogenic activities are increasing interest in producing alternative biofuels like biodiesel. Biodiesel, a green alternative energy source, can be harvested from a variety of biological sources. Increasing energy security, improving rural development, and the transition to a low-carbon economy are all critical factors for the advancement of biodiesel production. In this sense, the advances, opportunities, and future perspectives in biodiesel production technologies are discussed, while their limitations and challenges are critically explained. The present study focuses on a variety of established catalytic technologies as well as the potential of emerging technologies and their future prospects. The current challenges of conventional technologies (high expenses, sensitivity to the presence of water and FFA percentage, overlap with food consumption, and adverse environmental impacts) prohibit growth in biodiesel production to its full potential. On the other hand, new alternative techniques discussed in this study (enzyme-catalyzed transesterification, whole-cell biocatalysts, magnetic-assisted transesterifications, and plasma-assisted transesterifications) overcome these bottlenecks and introduce opportunities for bulk industrial scale-up and growth in biodiesel usage by lowering the production costs. Moreover, applications of glycerol by-products (such as epichloridrin) along with the glycerol-free method have been discussed for the economical production of biodiesel. These alternative technologies, aside from their impact on the environment and reducing GHG emissions, can be considered the solution to fossil fuel shortages and high demand. To this end, more research on the industrial production scale-up of emerging technologies is essential.