ABSTRACT
Limited stocks and exorbitant prices of petroleum products create the need of nding some suitable alternative fuels or fuel supplements (Wyman 1996; Lynd et al. 2005). Ethanol has especially attracted interest as an alternative transportation fuel for two reasons: (1) the oil crisis in the mid1970s stressed the dependence on the supply of petroleum, which can be reduced by the use of alternative fuels such as ethanol from renewable resources; and (2) if the ethanol production process only uses energy from renewable energy sources, no net carbon dioxide is added to the atmosphere, making ethanol an environmentally safe fuel (Kheshgi et al. 2000).
