Fermentation Vs Respiration : Definition, Types and Differences

The term ‘ferment’ is derived from the Latin word ‘fervere’ meaning "to boil." In the late 14th century, alchemists described fermentation process and it became the subject of scientific investigation in the 16th century. In the 1860s, Louis Pasteur studied the fermentation process. In 1897, German chemist Eduard Buechner first used fermentation process scientifically and fermented a sugar solution. His experiment is considered the beginning of the science of biochemistry which earned him the Nobel Prize in chemistry in 1907. Hence, the study of fermentation is known as Zymology. To make different industrial products such as wine, cheese, beer yogurt, and other products manufacturers apply the fermentation process.

Fermentation is the metabolic process by which organic molecules such as glucose, starch or sugar are converted by micro-organisms into acids, gases, or alcohol under anaerobic condition. To get energy yeast performs fermentation by converting sugar into alcohol while bacteria convert carbohydrates into lactic acid through the fermentation process.  Generally, bacteria and yeast need an oxygen-free environment to live. Many beverage and food industries use the fermentation process to make the conversion of sugars into ethanol. In this case, ethanol is used to produce alcoholic beverages by using yeast which releases CO2

Types of Fermentation

There are many types of the fermentation process. Among them, the most common fermentation processes are ethanol and lactic acid fermentation.  People produce commercial foods such as beer and bread by using an ethanol fermentation process. Lactic acid fermentation is used to flavor and preserve dairy products and vegetables.

Many foods and beverages industries use the fermentation process to produce many important industrial products:

  • Wine
  • Beer
  • Cheese
  • Yogurt
  • Alcohol
  • Lactic acid (to make sour foods
  • Sewage treatment
  • Hydrogen gas

Health Benefits of Fermentation

There are many fermented foods which are very beneficial to human health. Some benefits of fermented food are given below:

  • The body requires sufficient amount of digestive enzymes to make proper digestion, absorption, and utilization of food. Fermented food contains beneficial bacteria which enhance the digestive system for proper digestion.
  • Acetic acid, alcohol and lactic acid are produced by the organisms during the fermentation process which acts as bio-preservative to prevent spoilage.
  • Lactic acid also reduces pH level in the digestive tract which prevents the growth of harmful bacteria.
  • The fermentation process makes the food more easily digestible.
  • Fermented food contains lactobacilli which increase vitamin levels and enhance the digestibility.
  • In many cases, milk is difficult to digest. In this case, a type of bacteria is found in fermented dairy products which convert lactose into digestible lactic acid.
  • Fermented food also suppresses Helicobacter pylori infection which is an important risk factor for many gastrointestinal diseases.
  • Fermented food helps to decrease the exposure to chemical carcinogens by detoxifying the ingestion of carcinogens.
  • Fermented food produces metabolic products which cause to death of the programmed cell.
  • Fermented food produces compounds which prevent the growth of tumor cells.
  • Fermented food accelerates the immune system to protect itself against cancer cell propagation.
  • Lactobacillus containing fermented food prevents toxicity of heavy metals by excreting harmful heavy metals.
  • A fermented cabbage cuisine which is also known as Kimchi that contains strains and encourages the degradation of organophosphorus pesticides. It breaks down a cancer-causing food preservative called sodium nitrate.
  • Fermented food has anticancer effects because it alters the environment of the intestine and decreases the production of carcinogenic compounds.
  • The fermentation process helps to make different types of vitamins which improve the digestibility of some dietary nutrients.
  • Lactobacillus containing fermented food consumes the lactose in milk to produce lactic acid that makes to digestion very easy.

Chemical Reaction of Ethanol Fermentation

C6H12O6 (glucose) → 2 C2H5OH (ethanol) + 2 CO2 (carbon dioxide)

Chemical Reaction of Lactic Acid Fermentation

C6H12O6 (glucose) → 2 CH3CHOHCOOH (lactic acid)

Difference Between Fermentation and Respiration



In this process, O2 is not required.

In the presence or absence of O2, it may occur.

H2O is not produced.

H2O is produced as a byproduct.

It occurs in the cytoplasm of the cell.

It occurs in both the cytoplasm and mitochondria of the cell.

In this process, 2 ATPs are produced from one glucose molecule.

In this process, 36 ATPs are gbenerated from one glucose molecule.

During the fermanetation, broken down of glucose is not occurred completely.

During respiration, broken down of glucose is occurred completely.

The fermentation is  of two types: Ethanol and lactic acid fermentation.

Respirations are also of two types: Aerobic and anaerobic respiration.

During ethanol fermentation, glucose breaks down to produce ethanol and CO2 are produced while lactic acid fermentation, glucose breaks down to produce lactic acid.

During respiration inorganice end products, CO2 and H2O are generated.

In this case, oxidative phosphorylation does not occur.

In this case, ATPs are produced

 through oxidative phosphorylation.

In nature, different types of microorganisms like some bacteria, yeast, parasitic worms, etc. perform fermentation process.

All living organisms such as bacteria, archaeans, eukaryotic protists, fungi, plants, and animals perform respiration.

Organic molecules such as acetaldehyde and pyruvate are the final electron acceptor.

Mainly O2 is the final electron acceptor.

Small amount of energy is released due to occur incomplete oxidation of substrate.

Large amount of energy is released due to occur complete oxidation of substrates.


Respiration is the process where a set of chemical reactions are involved to produce energy. In this case, complete oxidation of food occurs and release COand water as by-products. It is the most effective procedure among the process of energy generation. It happens in higher plants and animals who are utilizing complex cell forms with high energy utilization. The total respiration process occurs in the cytoplasm and mitochondria of the cell where 36 ATPs are generated. It involves three steps:  glycolysis, citric acid cycle and electron transport chain.

The overall chemical reaction of respiration is shown below.

C6H12O6 + 6O2 → 6CO2 + 6H2O + 36ATP

Types of Respiration: There are the following three types of respiration:

  • Internal respiration: It is the gas exchange process between the blood and body cells.
  • External respiration: It is the breathing process where inhalation and exhalation of gases occur.
  • Cellular respiration: In this process, food is converted to energy. It is two types such as aerobic respiration and anaerobic respiration.

Concluding Remarks

All living organisms perform respiration to produce energy which is required for several activities such as growth, digestion, locomotion, etc.  Both fermentation and respiration are the cellular processes by which glucose is broken down in the cell to make energy. ATPs are produced in both fermentation and respiration processes. In the fermentation process,  NADH is not used in the oxidative phosphorylation to generate ATPs whereas in the respiration, NADH is used in the oxidative phosphorylation to produce ATPs.

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