The annual worldwide production of grapes is about 60 million
tons, with Europe accounting for about 44%. Grape marcs are the
main solid by-product of the wine industry, retaining about 15e
20% by weight of grapes after pressing (Torres et al., 2002), and are
primarily composed of skins, seeds, and sometimes stalks. It is
estimated that Mediterranean countries like Italy, Spain, and France
produce about 10 million tons per year of this raw residue
(Kammerer et al., 2004). Grape marcs are produced in large quantities
during a limited period of the year, at grapes harvest, and are
frequently disposed in open areas. According to the European
Council Regulation this ligno-cellulosic material, as well as other
wastes from wine and distillery industry, must be treated or