ETOILE · BIOETHANOL PRODUCTION VIA LIGNOCELLULOSIC FERMENTATION OF OLIVE OIL RESIDUES

Bioethanol has been increasingly becoming the renewable energy source that could reduce the oil dependence of the developed countries. Biorefineries can use the locally grown agriculture to produce ethanol. However, food chain supply is beginning to suffer the effects of the ethanol massive production raising major ethical concerns. Cellulosic ethanol can overcome the environmental risks that accompany the surge of harvest biomass feedstocks and thus can represent a real and pursuable technology for the future. According to the US DOE life-cycle analysis, ethanol from cellulose reduces greenhouse gas emissions by 90% compared to gasoline. Cellulosic biomass is the most abundant biomaterial on earth it is available almost in any country. Vegetal residues (wheat and rice straw, olive oils residues, etc.) can constitute a renewable source of raw materials for cellulosic ethanol production plants. Currently only a few pilot plants are producing bioethanol from lignocellulosic feedstock using an enzymatic hydrolysis process. Olive oil residues can constitute a valuable resource as a low cost feedstock for cellulosic ethanol production. At least 2 million tonnes of cellulose are discarded on the Mediterranean area every year, representing both an environmental problem and a waste of a valuable resource. The ETOILE project intends to develop a new integrated process where olive mill waste water from traditional three-phase centrifugation process is purified and at the same time cellulase enzymes are obtained. These enzymes are then used onto the solid olive oil residues, such as olive pulp and husks, to obtain ethanol. The research envisaged will thus provide a viable alternative to the growing bioethanol industry seeking for new cost-effective production processes competitive with oil industry.