The production of citrus fruit in Valencia’s region is estimated in 5 million tons/year. About 40% of the production goes towards human food market, 20% is used for juice manufacture and the remainder is nowadays a surplus without market place. In the industry of citrus processing for juice about 60% of the fruit weight is a residue consisting of waste peel, segment membranes and other by-products.

 The high amount of polysaccharides present in citrus fruit processing residue makes it a potential feedstock for biological conversion to ethanol It contains soluble and insoluble carbohydrates as its major components. The soluble carbohydrates are simple sugars, glucose, fructose and sucrose whereas insoluble components are hemicelluloses, cellulose and pectin which can be converted into fermentable sugars by a hydrolysis step.

 In this work, the potential of ethanol production from citrus fruit processing residue was assessed. Laboratory experiments were performed on orange peel waste by a first step of enzymatic hydrolysis with commercial enzymes (pectinase and cellulase) to convert all carbohydrates present in the substrate into fermentable sugars. Then fermentation tests of sugar containing media into ethanol using conventional baker yeast were carried out. Detailed results of this study will be presented.