Lactic acid fermentation and alcohol fermentation result in different products and occur in different places. Fermentation is the process of converting a sugar to an acid, gas or alcohol, and it is common throughout the various life forms. Fermentation is one of the most primitive and ancient metabolic mechanisms.
When one molecule of glucose is fermented alcoholically, it produces two molecules of ethanol alcohol and two molecules of carbon dioxide. By contrast, when a molecule of glucose undergoes lactic acid fermentation, it produces two molecules of lactic acid and no carbon dioxide. Lactic acid fermentation is the only fermentation process that does not produce a gas.
Fermentation is an anaerobic process, and most aerobic organisms attempt to utilize oxidative phosphorylation when possible, instead of fermentative processes. The aerobic pathway generates far more ATP, the cell’s energy currency, than anaerobic pathways do. The products of fermentation require oxygen to extract the energy contained in their bonds.
Lactic acid fermentation occurs in the muscles of animals engaged in strenuous activity. Lactic acid metabolism occurs when the muscles cannot obtain enough oxygen at a quick enough rate. Additionally, some bacteria and fungi produce lactic acid. Alcohol fermentation occurs in a variety of situations. Humans utilize it on a commercial scale to produce alcohol, and it occurs in rotting fruit.