What is fermented to produce ethanol during the fermentation process?

Ethanol is produced through the fermentation process primarily by the action of yeast on sugars. During fermentation, yeast converts sugars into ethanol and carbon dioxide in an anaerobic environment, meaning it occurs without oxygen. This process is utilized in various applications, such as in the production of alcoholic beverages like beer and wine, as well as in biofuel production.

The other substances listed do not undergo fermentation to produce ethanol. Proteins, fats, and minerals have different biochemical pathways and do not yield ethanol when subjected to fermentation. Proteins are broken down into amino acids, fats into fatty acids and glycerol, and minerals do not undergo fermentation at all as they are inorganic and do not participate in metabolic processes like fermentation. Therefore, sugars are the correct substrate for the fermentation process leading to ethanol production.