Introduction and Scope of Microbiology

Microbiology is the study of microorganism; a large diverse group of microscopic organism that exist as a single cell or cell clusters. It also includes virus which are microscopic but not cellular. Microbial cells are thus distinct from cells of animals and plants which are unable to live alone in nature and exist as only part of multicellular organism. A single microbial cell is generally able to carry out its life process of growth, energy generation and reproduction independently of other cells, either of same kind.

The existence of microbes was not established until Antony Von Leeuwenhoek (1678) could see them in simple microscope. Lewis Pasteur (1822 – 1895) investigated that boiled medium could remain clear in swan necked flask. Pasteur developed the procedure of gentle heating (pasteurization) to prevent the spoilage of beer and wine by undesirable microbes. This process was later used to prevent milk borne diseases in human beings.The germ theory of diseases has presented a great stimulus in microbiology and medicine. Louis Pasteur and Robert Koch (1843 -1910) were national heroes. Edward Jenner (1796) introduced vaccination against small pox, using bacteria from lesion; a similar diseases of cattle. In 1860s Joseph Lister introduced antiseptic surgery.

1879 – 1889 is called golden era of microbiology, because of development of powerful methodology. The discovery of viruses and their role in diseases was made possible by one of the Pasteur’s associated constructed porcelain bacteria filter in 1884. The first virus to be recognized as filterable was tobacco mosaic virus discovered by Russian botanist; Dmitri Ivanovsky and Martinus Beijerinck – Holland in 1899.   Role of microorganism in the carbon, nitrogen and Sulphur cycle in soil and aquatic habitat were discussed by Sergei N Winogradsky (1956 – 1963) and Martinus Beijerinck (1851 – 1931).

By 1970s knowledge of the basic processes of bacterial physiology, biochemistry and genetics had advanced to such a great extent that it was possible to manipulate the genetic material of cell, experimentally using bacteria as tool. It also became possible to introduce genetic material, DNA from foreign sources into bacteria and control its replication and characteristics. This led to the development of the field of biotechnology.

Scope of microbiology:

FieldStudy of
Medical MicrobiologyCausative agent of diseases, diagnostic procedure and preventive measures
Aquatic MicrobiologyWater purification, biological degradation of water, microbial examination, ecology
Aero MicrobiologyContamination of and spoilage, dissemination of diseases
Food MicrobiologyFood preservation, food preparation, food spoilage, food borne disease and their prevention
Agriculture microbiologySoil fertility, plant and animal diseases
Industrial MicrobiologyProduction of medicinal products such as antibiotics, vaccines, fermented beverages, production of protein and hormones.
Exo MicrobiologyExplanation of life in outer space
Geo-chemical MicrobiologyCoal, mineral and gas formation, recovery of mineral from low grade ore




About Author

Name : Pratiksha Shrestha

Ms. Shrestha holds masters degree in food engineering and bioprocess technology from Asian Institute of Technology (AIT) Thailand. She is currently working for Government of Nepal at Department of Food Technology and Quality Control (DFTQC), Kathmandu. She is also a teaching faculty in College of Applied food and Dairy Technology (CAFODAT) affiliated to Purbanchal university, Nepal.