Technical Options for Valorisation of Jatropha Press-Cake: A Review

Processing of Jatropha seeds to produce oil leaves press-cake (JPC) as a by-product. Based on extraction efficiency, 80-85% of seed remains as press-cake. In places where large quantities of Jatropha oil are extracted, mainly for biodiesel production, huge quantities of press-cake would be produced. JPC constitutes a substantial by-product that has multiple applications. Most papers in literature have focused on a narrow range of product streams arising from valorisation of JPC. This paper presents data on nine possible product streams of JPC valorisation. These are organic fertiliser, protein, animal feed, biocomposites, briquettes, bioethanol, biogas, pyloritic products and syngas. This makes it easier for comparative purposes as it aggregates existing data. The objective of this paper is to review empirical data available in literature on the conversion of JPC into high-value products and map the various valorisation options. The product streams can be placed into three main groups; fertiliser, energy carriers and industrial chemical products. The energy carrier group dominates with five products (briquettes, bioethanol, biogas, pyrolytic products and syngas). Conversion technologies for these products are well established. Biogas and briquettes are the most promising and have wide application. Use of JPC as fertiliser is also widely practiced. Work on production of various industrial chemicals, such as protein and biocomposites is at different stages of maturity. The paper shows a lot of work that has and is still being conducted in order to broaden the product streams of JPC valorisation.