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Unformatted text preview: 1 Bioethanol Production via Enzymatic Hydrolysis of Cellulosic Biomass Elba P.S. Bon (1) and Maria Antonieta Ferrara (2) (1) Chemistry Institute, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil and (2) Medicines and Drugs Technology Institute, Oswaldo Cruz Foundation, Rio de Janeiro, Brazil elba1996 (at) iq.ufrj.br 1 - INTRODUCTION Energy availability, supply and use play a central role in the way societies organize themselves, from individual welfare to social and industrial development. By extension, energy accessibility and cost is a determining factor for the economical, political and social interrelations among nations. Considering energy sources, human society has dramatically increased the use of fossil fuels in the past 50 years in a way that the most successful economies are large consumers of oil. However, geopolitical factors related to security of oil supply, high oil prices and serious environmental concerns, prompted by global warming - the use of petrol for transportation accounts for one-third of greenhouse gas emissions (Wyman, 1996) - have led to a push towards decreased consumption. Indeed, the world's strongest economies are deeply committed to the development of technologies aiming at the use of renewable sources of energy. Within this agenda, the substitution of liquid fuel gasoline by renewable ethanol is of foremost importance. Brazil has been a front-runner in the use of renewable fuels. The substitution of gasoline by ethanol started in 1975, when the Brazilian Government launched the “Proálcool Program" (Programa Nacional do Álcool). At the time of the first oil crisis, in the 1970s, the country imported 85% of its oil needs and the potential for ethanol production from sugarcane as a transportation fuel was in good agreement with the Government policy regarding energy supply independence. The Proálcool Program included incentives for distilleries and automobile companies that made ethanol-only cars. Although in the mid-1970s environmental concern was not a major driving force for substituting the use of gasoline, it is worth pointing out the global environmental benefits that have resulted from this policy since then. Presently, the ethanol industry in Brazil runs without government incentives and the biofuel is distributed by the Brazilian oil company Petrobras. The Brazilian fleet of 20 million cars (the total vehicle fleet including cars, light commercials, trucks and buses is around 24 million) runs on either a gasoline blend containing 22-24% ethanol or on 100% ethanol. Natural gas has also been marginally used. Ethanol consumption is forecast to increase as the number of “flex-fuel" cars, with engines able to run on both gasoline blend or ethanol, is forecast to increase from the present 4 million to 15 million in 2013 (Associação Nacional dos Fabricantes de Veículos Automotores - www.anfavea.com.br)....
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This note was uploaded on 12/13/2010 for the course GENETIK 12 taught by Professor Atillabasar during the Spring '10 term at Istanbul Technical University.
- Spring '10
- The Land