Difference Between Anaerobic Respiration and Fermentation

Main Difference

The main difference between anaerobic respiration and fermentation is that anaerobic respiration undergoes electron transport chain and citric acid cycle, whereas fermentation does not undergo electron transport chain and citric acid cycle.

Anaerobic Respiration vs. Fermentation

Anaerobic respiration refers to a category of cellular respiration that happens in the absence of oxygen, while fermentation refers to any chemical reactions to convert sugars into carbon dioxide and ethanol-induced by microorganisms. Anaerobic respiration undergoes electron transport chain and citric acid cycle, whereas fermentation does not undergo electron transport chain and citric acid cycle. Anaerobic respiration is an intracellular reaction; on the other hand, fermentation is an extracellular reaction. In the lack of oxygen, anaerobic respiration occurs; on the contrary, fermentation is brought by low oxygen concentrations. Glycolysis follows the electron transport chain and citric acid cycle in anaerobic respiration; conversely, glycolysis does not follow the electron transport chain and citric acid cycle in fermentation. In anaerobic respiration, the total production of ATP is 36; on the flip side, in fermentation, the total production of ATP is four. The enzymes cannot process the anaerobic respiration in an extracellular medium which is extracted from the cells, whereas in fermentation, the enzymes can process the reaction/procedure in an extracellular medium which is extracted from the fermenting cells.

Comparison Chart

Anaerobic RespirationFermentation
Anaerobic respiration refers to a category of cellular respiration that happens in the absence of oxygen.Fermentation refers to any chemical reactions to convert sugars into carbon dioxide and ethanol-induced by microorganisms.
Intracellular/Extracellular
An intracellular reactionAn extracellular reaction
Oxygen
In the absence of oxygenIn low oxygen concentration
After Glycolysis
Follows the electron transport chain and citric acid cycleDoes not follow the electron transport chain and citric acid cycle
Total ATP Production
36Four
In Vitro
Enzymes cannot process the anaerobic respiration in an extracellular medium which is extracted from the cellsEnzymes can process the reaction/procedure in an extracellular medium which is extracted from the fermenting cells

What is Anaerobic Respiration?

Anaerobic respiration refers to a category of cellular respiration that happens in the absence of oxygen and a stepwise incomplete catabolic breakdown of food materials. Anaerobic respiration occurs in many environments such as in marine sediments and freshwater, soil, subsurface aquifers, biofilms, and deep subsurface environments. Even present in environments where oxygen is present and also have microorganisms that lack oxygen because of the slow diffusion of oxygen gas. The way of the procedure is the same as aerobic respiration. This process begins with glycolysis as also in the fermentation process, but fermentation stops from it as anaerobic respiration does not. Anaerobic respiration continues the electron transport chain as well as citric acid cycle after the production of acetyl coenzyme A. As in aerobic respiration, the molecular oxygen is not the final electron acceptor in anaerobic respiration. Different types of organisms use different categories of final electron acceptor which can be nitrate ions, sulfate ions, or carbon dioxide. With the help of an example, this can be explained as methanogenic bacteria is a type of organisms that uses carbon dioxide as its final electron acceptor in anaerobic respiration. This bacterium produces methane gas as a byproduct. Anaerobic respiration plays an important role in ecological importance. Biogeochemical cycling depends on anaerobic respiration which significantly impacts the global warming and carbon cycle. Some specific types of anaerobic respiration are also important in bioremediation which converts toxic chemicals into less-harmful molecules to clean up the contaminated environment by using microorganisms.

Examples

Aerobic prokaryotes, and Eukaryotes.

What is Fermentation?

Fermentation refers to any chemical reactions to convert sugars into carbon dioxide and ethanol and breakdown of carbohydrates and other organic substances induced by microorganisms. Since fermentation doesn’t use the citric acid cycle or electron transport chain, so fermentation isn’t considered a type of respiration. The procedure of fermentation continues in which first sugar undergoes glycolysis. The hexose sugar glucose is gone down into two pyruvates during glycolysis. Glycolysis uses two ATP molecules while producing a total four molecules of ATP from the energy released from glycolysis. The pyruvate is oxidized into lactic acid, ethanol, formic acid, acetic acid. The raw material of fermentation is pyruvic acid. Some bacterial species and yeast perform fermentation.

Types

  • Ethanol Fermentation: It is used to produce bread, beer, and wine. Some other organisms undergo ethanol fermentation where the results are neither lactic acid nor pyruvate. In this case, these organisms make ethyl alcohol.
  • Lactic Acid Fermentation: It is used to produce lactic acid from lactose in yogurt production. Lactic acid fermentation happens in animal muscles and tissues when there is more required in energy in tissues. Distance runners are aware of lactic acid which build up in the muscles and cause cramping.

Examples

Beer, Wine, Cheese, Yogurt, Certain sour foods containing lactic acid, etc.

Key Differences

  1. Anaerobic respiration refers to a category of cellular respiration that happens in the absence of oxygen, while fermentation refers to any chemical reactions to convert sugars into carbon dioxide and ethanol-induced by microorganisms.
  2. Anaerobic respiration undergoes electron transport chain and citric acid cycle, whereas fermentation does not undergo electron transport chain and citric acid cycle.
  3. Anaerobic respiration is an intracellular reaction; on the other hand, fermentation is an extracellular reaction.
  4. In the lack of oxygen, anaerobic respiration occurs; on the contrary, fermentation is brought by low oxygen concentrations.
  5. Glycolysis follows the electron transport chain and citric acid cycle in anaerobic respiration; conversely, glycolysis does not follow the electron transport chain and citric acid cycle in fermentation.
  6. In anaerobic respiration, the total production of ATP is 36; on the flip side, in fermentation, the total production of ATP is four.
  7. The enzymes cannot process the anaerobic respiration in an extracellular medium which is extracted from the cells, whereas in fermentation, the enzymes can process the reaction/procedure in an extracellular medium which is extracted from the fermenting cells.

Conclusion

Above discussion concludes that anaerobic respiration undergoes electron transport chain and citric acid cycle, whereas fermentation does not undergo electron transport chain and citric acid cycle.

Janet White

Janet White is a writer and blogger for Difference Wiki since 2015. She has a master's degree in science and medical journalism from Boston University. Apart from work, she enjoys exercising, reading, and spending time with her friends and family. Connect with her on Twitter @Janet__White

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