Approximately 1.6 million ton per year of municipal solid waste (MSW) is pro­duced in the world. This waste incurs serious problems due to the progressive deterioration of the environment and also to the costs associated with its recollec­tion, transport, and disposal. It is estimated that the services for disposal, treat­ment, and economic utilization of MSW accounts for an annual market of $100 million worldwide, from which $42 million corresponds to North America, $42 million to the European Union, and only $6 million to South America, having the corresponding MSW volumes of 250, 200, and 150 million ton per year, respec­tively (Skinner, 2000). The organic fraction of MSW (that can reach more than 65%) is an extraordinarily heterogeneous mixture of materials in which materials with a lignocellulosic nature predominate: paper, cardboard, fruit and vegetable peels, garden residues, wood items, etc. The production of ethanol from MSW has already been patented (Titmas, 1999). MSW presents high amounts of inhibi­tors of its conversion process, which not only originate during the processing, but also come from the wastes themselves. Despite this, the possibility of producing ethyl alcohol from this waste has been demonstrated (Green et al. 1988; Green and Shelef, 1989). Many of these residues have significant starch contents especially in the case of wastes from marketplaces. In this case, the presence of discarded fruits with different maturity degrees provides the starch, which can be hydrolyzed using enzymes that degrade this polysaccharide and the cellulose coming from the lignocellulosic biomass present in these residues as well (Cardona et al., 2004).