What is fermentation?

Hint: Fermentation is the process which brings changes in the organic substrate by the action of various enzymes. It is the metabolic process. Products of fermentation can be different depending on the type of substrate and process of doing. It is the process in which energy is produced. Fermentation occurs in microorganisms as well as in humans and animals.

Complete answer:
In microorganisms, the anaerobic degradation of organic nutrients in order to produce ATP (Adenosine triphosphate) takes place by the process of fermentation. Humans have used this process to produce various types’ beverages and foodstuffs since the Neolithic age. It is common in all bacteria and eukaryotes. It generally occurs in all types of cells. Muscle cells carry out fermentation in case of exercising or anaerobic condition and produce lactic acid as a product.
Products formed by fermentation are Ethanol, Lactic acid and hydrogen.
In ethanol fermentation, conversion of one glucose molecule takes place into two ethanol molecules and two carbon dioxide molecules.
Homoplastic fermentation produces lactic acid. After the process of glycolysis pyruvate is converted into lactic acid by redox reaction.
Modes of fermentation are Batch, Fed - batch, open and continuous. Alcoholic beverages are produced by batch fermentation. Fed-batch fermentation is basically a feeding process during the process. Production of secondary metabolites is increased by using this process. Open type fermentation is mostly observed in the case of wastewater treatment. Fermentation has many applications such as pharmaceuticals, brewing, baking and dairy industries. It is also used for the production of vitamin C. Production of biopolymers by using microorganisms such as Rhodobacter sphaeroides is done by fermentation.

Note: Microbes are used to convert carbohydrates into ethanol and lactic acid. Some of the products of fermentation are wine, cheese, vinegar and medicines. Use of microbes is increasing day by day. These are also used in sewage industries for treating sewage waste. Use of microbes is increasing as per the advancement of biotechnology which results in simple fermentation processes.