Nonedible crops as alternative raw materials for biodiesel production: an overview

Biodiesel is a mixture of fatty acid alkyl esters which can be used as diesel substitute, being produced mostly from edible oils. Many research have been made to find alternative feedstocks for biodiesel production which (i) do not compete with the food market, (ii) are cheaper, and (iii) can be cultivated on nonagricultural/marginal land. According to the revision performed, among more than 300 oilseed plant species, only 40 have the potential for biofuel production, based on seed oil content. A relevant example of nonedible crops with high potential for biodiesel producing are Ricinus communis, Crambe abyssinica, Jatropha curcas, and Simmondsia chinesis. This review provides a comprehensive assessment of these nonedible crops suitable for biodiesel production due to their high seed oil content and details their characteristics as well as the advantages and constraints of their use for biodiesel. Among the nonedible crops analyzed, Crambe and Jatropha showed special interest to be cultivated in Portugal.