Energy

Bioethanol

Ethanol has always been used for internal combustion engines, as demonstrated by the history of cars. But, although the initial large availability and the low cost of hydrocarbons had not allowed to use them as fuels, after the oil shock of 1973 many other products were studied to replace car fuel (petrol and gas oil). Today, the product that shows a better compromise between price, availability and performance is ethanol. 
The synthesis of biomass ethanol is divided into four stages:

• production of biomass by fixing atmospheric CO2 into organic carbon
• conversion of biomass into a food that can be used for fermentation (usually as a sugar), by applying one of the many technological processes available: this conversion is what mainly differs with the various technological solutions for bioethanol conversion
• fermentation of biomass intermediates by using bio-catalizers (micro-organisms like yeast and bacteria) in order to obtain a scarcely concentrated solution of ethanol. This stage can be considered as the oldest biotechnology ever developed by men
• by processing the fermentation product the result is: combustible ethanol and by-products that can be used to produce other fuels, chemical compounds, heat and electric energy. 

All these last processes, even though they are very different, conclude with the fermentation synthesis. The alcohol fermentation is a process that transforms the glucides contained in vegetal productions into ethanol.