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For thousands of years, ethanol has been produced for human consumption and also for thousands of years, it has been possible making alcoholic concentrated by distillation.

At present, it is looking to produce ethanol from carbohydrates such as sucrose or starch. Alcohol is being used mixed with gasoline as fuel for automobiles. In other countries, ethanol is being used to produce ethylene and other petrochemical products.

Brazil in 1982, approximately 30% of oil imports had been replaced by ethanol produced from sugar cane (5.2 x 106 m3), representing 60-80 fermentation plants. The plants are capable of 20000-570000 m 3 / year.

Bioprocessing
Batch: starts aerobically for maximum biomass, anaerobic conditions because if begin too soon, the population density is not high enough to obtain a good conversion rate. May be required ventilation for a short time to avoid yield losses

Continuous: optimal growth of yeast and ethanol production are carried out under conditions of sugar limitation (<> microaerobic (0.2 to 5 MgO 2 / g dry matter / h).

Theoretically can be obtained from 1 g of glucose, 0.511 g of ethanol. When cigars are fermented substrates, the yield is 95% and 91% is reduced when using industrial grade raw materials. 100 g of glucose will produce 48.4 g pure ethanol, 46.6 g of CO2, 3.3 g glycerol and 1.2 g of biomass. 100kg of starch (from 180 kg of maize) will produce 51.5 L of ethanol.

As ethanol concentration increases, growth slows. The growth usually stops at 5% ethanol (v / v), the production rate is reduced to zero to 6-10%