Thermochemical and Biochemical Conversion of Olive Stones
Manuel Cuevas1, Sebastian Sanchez1 and Juan Francisco Garda2
department of Chemical, Environmental and Materials Engineering, University of Jaen, Jaen, Spain
2Instituto de la Grasa, Spanish National Research Council. Seville, Spain
The olive tree is extensively cultivated in countries of the Mediterranean basin; the area currently under cultivation covers roughly 5.5 106 ha in the EU and 11.0 106 ha in the world. By-products from olive culture and related industries, such as prunings, leaves, olive pomace, and olive stones, are interesting materials for the production of energy, food, fertilizers and other chemicals due to the large available feedstock and their chemical composition. Olive stones are by-products derived from the olive oil extraction industry and from manufacturing of pitted-table olives. Basically, there are two current ways for valorization of olive stones: thermochemical (energy source by combustion, gasification or pyrolysis) and biochemical (ethanol and xylitol production) conversion. Bioconversion of olive stones can also provide other high added-value products such as xylooligosaccharides or natural antioxidants (tyrosol and hydroxytyrosol). Finally, comparison of the different procedures and potential future applications will be discussed as well.