Ethanol fermentation, also called alcoholic fermentation, is a biological process which converts sugars such as glucose, fructose, and sucrose into cellular energy, producing ethanol and carbon dioxide as a side-effect. Because yeasts perform this conversion in the absence of oxygen, alcoholic fermentation is considered an anaerobic process. It also takes place in some species of fish (including goldfish and carp) where (along with lactic acid fermentation) it provides energy when oxygen is scarce.

Ethanol fermentation has many uses, including the production of alcoholic beverages, the production of ethanol fuel, and bread baking.
Source : https://en.wikipedia.org/wiki/Ethanol...