What is fermentation?
Fermentation is an anaerobic metabolic process in which an organism converts a carbohydrate to an alcohol or an acid.
The first step in all fermentation processes is glycolysis, the conversion of glucose to pyruvate:
There are two main types of fermentation; one converts pyruvate into lactate (lactic acid) and the other into ethanol.
In lactic acid fermentation, pyruvate is converted into lactic acid.
In alcohol fermentation,the pyruvate is decarboxylated to acetaldehyde, and then into ethanol.
In an aerobic process, the pyruvate is converted by respiration to carbon dioxide and water.
Here is a summary of the three possible fates of pyruvate: