Table of Contents
What is Fermentation?
The metabolic process that induces chemical changes in organic substrates by the action of enzymes is known as fermentation. It uses microorganisms such as bacteria, algae and fungi. The use of this process on a large scale to produce pharmaceuticals, enzymes and proteins is known as industrial fermentation.
Media Requirements
To obtain a good product from fermentation, the medium in which the microorganisms are grown must be supplied with enough energy sources and nutrients. Several factors must be kept in mind before designing or choosing the growth medium for fermentation. To obtain primary metabolites such as citric acid and ethanol, the media should be rich in components that support good growth. Similarly, for secondary metabolites such as alkaloids and antibiotics, the substrate requirement for product formation must be kept in mind.
While doing fermentation on a small scale, such as in laboratories, pure graded chemicals are used that are expensive. However, in large scale industrial fermentation, cheaper and unrefined chemicals are used. Therefore, the choice of media for fermentation is a crucial step that requires a lot of thought processes.
Media Components
The fermentation media can either be liquid, known as broth, or it can be a solid-state fermentation. The media should satisfy all the nutritional requirements of the microorganism and should also obtain the target molecule. A typical media requires a carbon source, a nitrogen source, salts, water and micronutrients. Let us look at them one by one.
- Carbon Source
- Nitrogen Source
- Growth Factors
- Miscellaneous
Typically sugars and carbohydrates are used as carbon sources, but alcohols may also be used in making products such as vinegar. For laboratory uses, refined and pure carbon sources such as glucose, sucrose and glycerol are used that give a uniform product. However, in the case of industrial fermentation, inexpensive sources such as whey, malt extract, molasses, corn steep liquor or sugar cane juice are used.
The nitrogen source for microorganisms may be used in the form of organic or inorganic compounds. Inorganic sources include ammonium salts or the free form of ammonia. Inexpensive nitrogen sources are used for bulk production, such as tryptone, peptone, soy meal, corn steep liquor and yeast extract.
Trace salts and growth factors are important components in the fermentation media. Yeast extract is a good source of vitamins and macronutrients. Trace elements such as copper, zinc, iron, cobalt, molybdenum, manganese are all usually found in the unrefined nitrogen sources but may need to be added when using pure sources.
The process of fermentation sometimes produces a large amount of gas that forms a layer of foam and hinders the process. To get rid of this problem, antifoaming agents are also added to the fermentation medium. To stabilise pH of the media, mineral buffering salts such as phosphates and carbonates are also added. The addition of chelating agents may also be required when high concentrations of metals are present in the media.
Optimisation of the Fermentation Medium
Optimisation is the process of developing a fermentation medium that gives the best quality and quantity of the target product. One of the most common methods to optimise a media is to optimise one factor at a time (OFAT). In this method, only one component of the media is changed while others are kept constant, and the results are observed. Similar observations can be done for all the components in a group of experiments, and the best optimised media can be prepared by analysing the results.
Visit BYJU’S for more information about NEET.
Also Read:
Comments