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Microbial World
2013-03-06, 9:49 PM

Microbial World

Microbial world is a realm of life made up of micro organisms, the branch of biological sciences concerned with the study of microbes’ known as microbiology.

Microorganisms are unicellular, too small to be seen with the naked eye. Among all forms of life on the earth these are stronger but their occurrence is undervalued because of small size (0.2-2microns) belongs to plant and animal kingdom.

These were first observed by A.V.Leewenhoek.

Based on their structures they are different kinds namely

ü  Bacteria: Lactobacillus, Rhizobium.

ü  Viruses: Mumps, Measles.

ü  Protozoans: E.hystolitica, P.vivax.

ü  Mycoplasms: C.trachomatis, T.pallidum

ü  Algae: Nostoc, Volvox.

ü  Fungi: Yeasts, Moulds.


Ø  Useful Micro organisms

Majority of micro organisms are harmful to living organisms and some of them are highly beneficial. By the decomposition of dead bodies of plants and animals  they will return back to the environment supplying nutrients to the other plants and animals for their growth.

Now-a-days varieties of micro organisms are using to produce the substances on large scale known as microbiology which is developed into microbial biotechnology or industrial microbiology.

Micro organism are very useful in the preparation of food, production of antibiotics, organic acids, steroids, enzymes, bio fertilizers etc.

Ø  Useful Products obtained by Micro organisms.

·         Ripening of Cheese

The cheese which is prepared without using the water known as ripening.

The coagulation of milk protein ‘casein’ results the semi solid substance known as cheese is formed by the activity of Streptococcus liquifaciens bacteria and moulds like Pencillium and Aspergillus. Depending on the type of milk, micro organisms, temperature and time they are about 300 varieties of cheese. Of that

ü  Cottage cheese: It is a soft, lumpy white cheese made from the curds of slightly soured milk. Examples: Ricotta, Mascarpone.

ü  Cream cheese: It is soft rich cheese made from unskimmed milk.            

Examples: Crowdie, Caboc.

ü  Hard cheese: It is a type of cheese produced by repeatedly vigorous stirring and draining a mixture of curd and whey.

Examples; Swiss, Cheddar etc.

ü  Soft cheese: It is a type of cheese which has not been pressed and has edible white blooms rind produced by spraying the culture of Pencillium on the surface.

Examples: Camemberd, Liederbrauz

·         Curdling of Milk

The fermented product obtained from the boiled milk known as curd, fermentation is done by lactic acid bacteria which help for the conversion of curd from milk by bringing milk proteins and fat globules together.

ü  The solid material of the curd: Butter.

ü  The liquid material of the curd: Butter milk.

·         Bread making

In the preparation of bread Sacchoromyces cerevisiae ferment the sugars of dough to produce carbon dioxide and alcohol. The gas helps in the production of bread with porous, spongy structure and also in flavoring substances.

·         Variety of foods

With the help of Sacchoromyces faecalis and Leuconostoc mesenteroids, idly and dosa are produced by overnight fermentation.

·         Production of Antibiotics

These are the accessory growth substances required by the organisms in low concentration and are synthesized by bacteria, yeast cells and fungi during the fermentation process.

Examples: Riboflavin: Ashby a gossyypii, Phylloquine: Propionic bacterium.

·         Digestion &Physiological Process

Numbers of micro organisms are present in the stomach. Lower part of small and large intestine of animals and human beings.

The metabolic production of lactic acid bacteria inhibit the growth of bacteria and releases phylloquine vitamin into the intestine then supplies to the body hence normal bacterial flora should be maintains in the human intestine.

Examples: E.coli, Methanogenic bacteria.



Category: My files | Added by: anve
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sir when you give revision schedule?

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