Question

Describe Fermentation and its economic importance.

Answer 1

Fermentation is a type of cellular respiration found in some unicellular and multicellular organisms which do not require oxygen i.e. they perform anaerobic respiration and this results in the production of ethanol from glucose and a small amount of energy.

The economic importance of fermentation:

Industrial alcohol production:

Ethanol or ethyl alcohol is industrially made from a variety of agricultural products such as molasses, fruits, grains etc. Ethanol production is carried out by yeasts and bacteria through fermentation.

Ethanol production by yeasts:

Yeast species primarily used for fermentation of ethanol are Saccharomyces cerevisiae and Saccharomyces uvarum These are grown in large fermentors and fed with the nutrient media such as sugars, carbohydrates etc.

Yeast breakdowns carbohydrates (sugars) into alcohol and carbon dioxide in the absence of oxygen which is summarized in the reaction-

$C_6{H}_{12}{O}_6$ + yeast $\to$ $2C_2{H}_{5}OH+C{O}_2$ + Energy

Ethanol production by bacteria:

A large number of bacteria are capable of ethanol fermentation such as Clostridium, Leuconostoc, Spirochaeta etc. On fermentation, these produce ethanol, water and small amounts of other alcohols.