What is Fermentation and How Does it Work?

Summary

Fermentation is an anaerobic process in which organisms convert sugars into acids or alcohols. Yeast and other microbes use it to make foods and drinks, and human muscles can also rely on it when oxygen is limited.

How fermentation works

• Glycolysis begins the process: Sugar is broken down, releasing energy and leaving two molecules of pyruvate.
• Pyruvate is then converted into other compounds rather than continuing through the usual route of cellular respiration:
  • Lactic acid fermentation: Pyruvate is converted into lactate (lactic acid).
  • Alcoholic fermentation: Pyruvate is converted into ethanol.
• Fermentation is anaerobic because it does not require oxygen.

Where it is used

• Muscles: During intense exercise, when oxygen is insufficient, muscles can switch to lactic acid fermentation.
• Food production: Fermentation is used to make dairy products, bread, and pickles.
• Alcoholic drinks: Alcoholic fermentation is used to produce beverages such as beer and wine.

The video also says fermentation produces carbon dioxide. However, not every fermentation pathway produces it.

Speakers and sources

• Speaker: One unnamed narrator; no other speakers are featured.
• Sources credited in the video metadata: ThoughtCo, “What Is Fermentation?” and Khan Academy, “Fermentation and Anaerobic Respiration.”