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Loral 3. Sugar Separation Approximately half of the energy value in the cellulosic feedstock is captured in the sugars produced in hydrolysis. Fermentation will be more efficient if this is separated from other compounds, especially lignin. This can be accomplished with membranes. The lignin also contains about half of the energy and can be used as an energy source for the process. 4. Fermentation Once the cellulose has been broken into sugars, microorganisms are used to ferment the sugar and produce ethanol. Traditionally, baker's yeast has long been used in the brewing industry to produce ethanol from hexoses (6- carbon sugar). When lignocellulosic biomass is hydrolyzed to produce sugars, several sugars are produced including xylose and arabinose (5- carbon sugars). As a result, specially engineered microorganisms, mainly yeasts, have been developed and utilized in fuel ethanol production from cellulose. 5. Distillation The liquid resulting from fermentation is separated from any solids and heated to volatize the ethyl alcohol which is then condensed. The process is repeated to increase the ethanol concentration. An adsorption technique may be used to remove the remaining water to produce anhydrous ethanol. Because of the concern about using food crops to produce fuels and the potential cost savings, a large number of companies have developed cellulosic ethanol technologies, including: • Abengoa Bioenergy • Alico • BlueFire Ethanol • China Resources Alcohol Corporation (CRAC) • Dyadic International, Inc. • GreenField Ethanol • Gulf Coast Energy • Iogen Corporation • Mascoma • POET Biorefinery • Range Fuels • SunOpta Inc. • Verenium Corporation • Xethanol 1.3.2 Biogas Roger Haug defines composting as "the biological decomposition and stabilization of organic substrates, under conditions that allow development of thermophilic temperatures as a result of biologically produced heat, to produce a final product that is stable, free of pathogens and plant seeds, and can be beneficially applied to land." 15 Composting of MSW or a portion of MSW such as yard waste is usually carried out in the presence of air (aerobically) to produce a soil amendment and to reduce the amount of MSW being deposited in landfills. When composting is done in the absence of air (anaerobically), the biogas produced contains a significant amount is Roger T. Haug, The Practical Handbook of Compost Engineering, Lewis Publishers, 1993. GBB/C08027 -01 B -17 August 15, 2008