Valorisation of olive oil industry solid waste and production of ethanol and high value-added biomolecules

Olives (Olea europaea L.) are the leading commercial tree crop, with olive oil production being one of the most economically important agro-food sectors, in the Mediterranean basin. In addition to oil, the three-phase oil industry generates olive mill solid waste (OMSW) and olive mill wastewater byproducts. Disposal of these waste products in the field could create a serious environmental problem due to the phytotoxic nature of the phenolic compounds and low biodegradation of the lignocellulosic biomass. Management of the large amount of waste, both solid and liquid, stemming from the production of olive oil poses a challenge for olive mill operators and producers from both economic and environmental perspectives. The main suggested products from OMSW include compost, biochar, activated carbon, biogas, and bioethanol. Valorisation of OMSW biomass subjected to these different uses is discussed.