Renewable fuels via catalytic hydrodeoxygenation of lipid-based feedstocks

Energy security concerns have led to the search for alternative and renewable energy resources. Biomass with high lipid content is an attractive feedstock for producing renewable fuels. Biomass-derived fats and oils can be readily converted into biodiesel via the well-studied transesterification process. However, owing to the alcohol component of biodiesel, which contains oxygen, it cannot serve as a fully-fledged replacement for conventional petrodiesel. In this respect, renewable diesel obtained via catalytic hydrodeoxygenation (HDO) of lipid-based feedstocks is a more attractive and fungible option. This process makes it possible to produce fuels with the chemical composition indistinguishable from that of petroleum-derived products. Since all kinds of biomass have high oxygen content, comprehensive research of the catalytic HDO process arouses great interest. This article aims to review state-of-the-art studies related to the catalytic HDO of lipid-based feedstocks from the last decade. The suitability of microalgae as a feedstock for renewable fuel production, as well as the possible advantages of processing lipid-based feedstocks using aqueous HDO, are also addressed in this review.