ABSTRACT
The use of ethanol as a fuel additive or directly as a fuel source has grown in popularity due to international governmental regulations and, in some cases, economic incentives based on environmental concerns, as well as a desire to reduce dependence on petroleum. Brazil is a pioneer in producing ethanol for cars, a program that started in 1927 when it was installed the first alcohol pump that continued to work until early 1930s. The biotechnological processes are responsible by the vast majority of ethanol produced. About 95% of the world ethanol is of agricultural products. Second generation biofuels are produced from biomass in a more sustainable fashion, which is truly carbon neutral or even carbon negative in terms of its impact on carbon dioxide concentrations. Technology for conversion of cellulose to ethanol requires chemical or enzymatic conversion of the substrate to fermentable sugars followed by fermentation by a microorganism such as S. cerevisiae.
