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Microbiology is the study of microorganisms. Microorganisms are living beings so small that they cannot be seen with the naked eye, but only with the magnification of a microscope. Microbiologists study an enormous diversity of unicellular and cell-cluster life. Microorganisms include not only plants and animals, but tiny creatures that fall into neither of those kingdoms. Some are eukaryotes (with a nucleus) such as fungi and protists, and others prokaryotes (without a nucleus). such as bacteria and certain algaes. Viruses are also included in the field of microbiology, even though these molecules of DNA and RNA that infect cells have not been accepted as living under the traditional definitions used by biologists.


Why study Microbes?

Microbiology improves human life

Microbes are important to people because they can cause illness in humans and animals, after all - a common name for them is "germs"! Their study results in ways to combat the diseases caused by infection. It is microbes that are responsible for much of the decay of dead material and for the detoxification of pollutants in the environment. Scientists have also exploited their knowledge of microbes to produce biotechnologically important enzymes such as Taq polymerase, reporter genes for use in other genetic systems and novel molecular biology techniques such as the yeast two-hybrid system.Microbes are also responsible for many beneficial processes such as industrial fermentation (e.g. the production of alcohol and dairy products), antibiotic production and as vehicles for cloning in higher organsisms such as plants.

=Microbiology holds a key to understanding the processes of life- Microorganisms carry out all of the basic processes that are vital for understanding the naturure of living beings: growth, reproduction, and metabolism to name a few. The tremendous diversity of microbes along with the rapidity of their reproduction allows biologist to gain insight into these important processes in the laboratory.


Bacteria were first observed by Anton van Leeuwenhoek in 1676 using a single-lens microscope of his own design. The name "bacterium" was introduced much later, by Ehrenberg in 1828, derived from the Greek word βακτηριον meaning "small stick". While Antony van Leeuwenhoek is often cited as the first microbiologist, the first recorded microbiological observation, that of the fruiting bodies of molds, was made earlier in 1665 by Robert Hooke.

The field of bacteriology (later a subdiscipline of microbiology) is generally considered to have been founded by Ferdinand Cohn (1828-1898), a botanist whose studies on algae and photosynthetic bacteria led him to describe several bacteria including Bacillus and Beggiatoa. Ferdinand Cohn was also the first to formulate a scheme for the taxonomic classification of bacteria.

Louis Pasteur (1822-1895) and Robert Koch (1843-1910) were contemporaries of Cohn’s and are often considered to be the founders of medical microbiology. Pasteur is most famous for his series of experiments designed to disprove the then widely held theory of spontaneous generation, thereby solidifying microbiology’s identity as a biological science. Pasteur also designed methods for food preservation (pasteurization) and vaccines against several diseases such as anthrax, fowl cholera and rabies. Robert Koch is best known for his contributions to the germ theory of disease, proving that specific diseases were caused by specific pathogenic microorganisms. He developed a series of criteria that have become known as the Koch's postulates. Koch was one of the first scientists to focus on the isolation of bacteria in pure culture resulting in his description of several novel bacteria including Mycobacterium tuberculosis, the causative agent of tuberculosis.

While Louis Pasteur and Robert Koch are often considered the founders of microbiology, their work did not accurately reflect the true diversity of the microbial world because of their exclusive focus on microorganisms having medical relevance. It was not until the work of Martinus Beijerinck (1851-1931) and Sergei Winogradsky (1856-1953), the founders of general microbiology (an older term encompassing aspects of microbial physiology, diversity and ecology), that the true breadth of microbiology was revealed. Martinus Beijerinck made two major contributions to microbiology: the discovery of viruses and the development of enrichment culture techniques. While his work on the Tobacco Mosaic Virus established the basic principles of virology, it was his development of enrichment culturing that had the most immediate impact on microbiology by allowing for the cultivation of a wide range of microbes with wildly different physiologies. Sergei Winogradsky was the first to develop the concept of chemolithotrophy and to thereby reveal the essential role played by microorganisms in geochemical processes. He was responsible for the first isolation and description of both nitrifying and nitrogen-fixing bacteria.

The field of microbiology can be generally divided into several subdisciplines:

  • Microbial physiology: The study of how the microbial cell functions biochemically. Includes the study of microbial growth, microbial metabolism and microbial cell structure.
  • Microbial genetics: The study of how genes are organised and regulated in microbes in relation to their cellular functions. Closely related to the field of molecular biology.
  • Medical microbiology: The study of the role of microbes in human illness. Includes the study of microbial pathogenesis and epidemiology and is related to the study of disease pathology and immunology.
  • Veterinary microbiology: The study of the role in microbes in veterinary medicine.
  • Environmental microbiology: The study of the function and diversity of microbes in their natural environments. Includes the study of microbial ecology, microbially-mediated nutrient cycling, geomicrobiology, microbial diversity and bioremediation. Characterisation of key bacterial habitats such as the rhizosphere and phyllosphere.
  • Evolutionary microbiology: The study of the evolution of microbes. Includes the study of bacterial systematics and taxonomy.
  • Industrial microbiology: The exploitation of microbes for use in industrial processes. Examples include industrial fermentation and wastewater treatment. Closely linked to the biotechnology industry. This field also includes brewing, an important application of microbiology.
  • Aeromicrobiology: The study of airborne microorganisms.
  • Food Microbiology: The study of microorganisms causing food spoilage.
  • Pharmaceutical microbiology: the study of microorganisms causing pharmaceutical contamination and spoillage.
Fermenting tanks with yeast being used to brew beer


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The WP article was entitled Microbiology
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