Fermentation: Meaning, Process, Types and Importance

Fermentation is a biological process that occurs in the absence of oxygen, where microorganisms, such as yeast or bacteria, break down organic substances (usually sugars or other carbohydrates) to produce energy. The study of fermentation is called “zymology”. Fermentation is widely used in various applications, including the production of food and beverages (e.g., bread, beer, wine, yogurt), biofuel production, and the preservation of certain foods (e.g., pickles).

What is Fermentation?

Fermentation is the anaerobic breakdown of carbohydrates and other organic compounds into alcohols, organic acids, gases, etc. with the help of micro-organisms or their enzymes. It’s an essential process used in industrial processes and in nature for providing energy and metabolic products for organisms in environments with limited or no oxygen.

Examples of Fermentation

The various types of examples of fermentation are:

• Lactic acid bacteria ferment milk sugars (lactose) into lactic acid, curdling the milk and creating yogurt
• Yeast is also used in baking to leaven bread through alcoholic fermentation.
• Lactic acid fermentation, along with other biochemical processes, is involved in the production of various types of cheese.
• Acetic acid fermentation, performed by Acetobacter bacteria, is used to make vinegar.
• Yeast converts sugars in fruits (e.g., grapes for wine, barley for beer) into ethanol and carbon dioxide through alcoholic fermentation. This process is important for making beer, wine, and other spirits.
• Fermentation is used in the production of biofuels, such as ethanol.

Process of Fermentation

Fermentation occurs under anaerobic conditions, it is an alternative pathway for cells to generate energy. The mechanism of fermentation is as follows:

• In the initial step glucose is breaks down into pyruvate molecules in the cytoplasm of cells and generates a small amount of ATP and NADH.
• In the absence of oxygen, cells can’t undergo the complete oxidation of pyruvate as in aerobic respiration. NADH produced during glycolysis is to be converted back to NAD+ to keep glycolysis running. In fermentation electrons is transfered from NADH to the organic molecules derived from the original sugar.
• End products depend on the type of fermentation and the microorganisms involved. For example, in alcoholic fermentation, pyruvate is converted into ethanol and carbon dioxide, while in lactic acid fermentation, pyruvate is reduced to lactic acid.

Types of Fermentation

Fermentation are of various types depending upon the specific microorganism involved in the reaction and on the resulting product. Different types of fermentation are as follows:

Lactic Acid Fermentation

It is a metabolic process by which starch or sugar is converted into metabolite lactate, which is lactic acid by yeast strains and bacteria. It is an anaerobic fermentation process that occurs in some bacteria and animal cells when energy spend is more than the supplied oxygen. In this process, one glucose molecule is converted into pyruvate and then into lactic acid.

CH₃CO.COO + H⁺ + NADH₂ —> CH₃CHOHCOOH + NAD⁺

Alcohol Fermentation

Ethanol Fermentation or Alcohol Fermentation is a biological process where pyruvate, the end product of glycolysis, is broken down into Ethanol (alcohol) and carbon dioxide. Yeast performs this process in the absence of oxygen, alcoholic fermentation is an anaerobic process. Ethanol Fermentation is mainly used for the preparation of Alcoholic beverages like beer and the production of ethanol fuel.

CH₃COCOO + H⁺ —> CH₃CHO + CO₂

CH₃CHO + NADH—> CH₃CH₂OH + NAD⁺

Acetic acid Fermentation

Acetic acid is also known as vinegar. The production of acetic acid generally involves two processes, the first is using yeast alcohol produced from sugar and the second is utilizing acetic acid bacteria to oxidize ethyl alcohol to acetic acid through acetaldehyde. Fermentation of acetic acid is done by two methods, surface fermentation and submerged fermentation.

CH₃CH₂OH —> CH₃CHO —> CH₃C(HO)₂ —> CH₃COOH

Butyric acid Fermentation

It is a metabolic process in which microorganisms, break down organic compounds like carbohydrates and produce butyric acid as a by product. Butyric acid is a type of short-chain fatty acid, that finds application in digestion, gut health, and industrial applications.

C₆H₁₂O₆ –––>2C₄H₈O₂ + 2CO₂ + 2H₂

Importance of Fermentation

Fermentation have importance across various sectors due to its diverse applications and contributions to numerous processes. Some of the importance of fermentation are as follows:

• Fermentation has many uses in various fields ranging from the food industry to the manufacturing industry. 
• Food products can be preserved and stored using the fermentation process, which increases the shelf life of food.
• Various flavors and tastes can be added to food items through this process.
• Fermentation is used to produce ethanol which is used as biofuel, it is generated from feedstock like grains, sugar cane, sugar beet, and cassava which is a renewable resource.
• Certain types of fermentation can be utilized to manage organic waste and produce energy-rich byproducts like biogas.
• A number of products are made with this technique like dyes, inks, coagulants and binding agents, etc. 
• Fermentation helps in digestion by degrading nutrients into digestible form. 
• Some fermentation processes occur naturally in the human gut, playing a role in the digestion of dietary fibers and the synthesis of certain vitamins.

Advantages of Fermentation

Fermentation provides a variety of advantages across various industries and applications, making it an important process for numerous purposes. Some of the advantages of fermentation are as follows:

• Fermentation preserves food by creating an environment conducive to the growth of beneficial microorganisms while inhibiting harmful ones, thereby increasing the shelf life of food products.
• Fermentation is important for making biofuels like ethanol, which can replace fossil fuels. This helps reduce pollution and our reliance on limited natural resources.
• Fermentation processes, like anaerobic digestion, convert organic waste into useful products such as biogas and compost.
• Fermentation is used in the synthesis of various chemicals, like organic acids, enzymes, and amino acids, which have applications in industries such as food, agriculture, and textiles.
• Fermentation-derived ingredients are used in skincare and cosmetic industries for their potential benefits, such as improving skin health and hydration.
• Fermentation is used to produce a variety of pharmaceuticals, vaccines, and therapeutic proteins. This helps in medical treatments and biotechnological research.

FAQs on Fermentation

1. What is Fermentation?

Answer:

Fermentation is a biological process in which microorganisms, such as yeast or bacteria, break down organic substances (usually sugars) to produce energy, resulting in the conversion of these substances into various products, such as alcohol, carbon dioxide, acids, or gases.

2. What are the Key Microorganisms Involved in Fermentation?

Answer:

Microorganisms commonly involved in fermentation include yeast (for alcoholic fermentation), lactic acid bacteria (for lactic acid fermentation), and Acetobacter (for acetic acid fermentation).

3. What are the uses of Fermentation?

Answer:

Common products of fermentation include alcoholic beverages like beer and wine, dairy products like yogurt and cheese, pickled foods, vinegar, and biofuels.

4. Who discovered Fermentation?

Answer:

In 1857 Louis Pasteur discovered fermentation.