Microbiology is one of the most applied of all the biological sciences which did not exist as a true science before the later part of 19th century.
It is defined as the study of microorganisms that is the organisms which are of microscopic dimensions and too small to be clearly perceived by the unaided human eye.
Because most of the microorganisms are only a few thousand of a mm in size, they can only be seen with the aid of microscope.
Due to the invisibility of microbes to the naked eye and the need for special techniques to study them, microbiology was the last of the three major divisions in biology (the other two are botany and zoology) to develop.
The branches that come under the large and expanding umbrella of microbiology are categorized into pure and applied sciences.
Major Fields of Pure Sciences
Bacteriology: Study of bacteria
Mycology: Study of fungi (achlorophyllous, heterotrophic, eukaryotic with a rigid cell wall containing chitin/cellulose)
Protozoology: Study of protozoans (animal like single celled eukaryotic organisms).
Virology: Study of viruses and viral diseases.
Algology or Phycology: Study of algae.
Parasitology: Study of parasitism and parasites (include pathogenic protozoa, helminthes worms and certain insects).
Microbial ecology: Study of interrelationships between microbes and environment.
Microbial morphology: Study of detailed structure of microorganism.
Microbial taxonomy: Concerned with classification, naming and identification of microorganism.
Microbial Physiology: Study of metabolism of microbes at cellular and molecular levels.
Microbial genetics and Molecular Biology: Study of genetic material, structure and function and biochemical reactions of microbial cells involved in metabolism and growth.
Major Fields of Applied Microbiology
Industrial Microbiology: Concerned with industrial uses of microbes in production of alcoholic beverages, vitamins, NH2-acids, enzymes, antibiotics and other drugs.
Agricultural Microbiology: Study of relationships of microbes and crops and on control of plant diseases and improvement of yields.
Food Microbiology: Deals with interaction of microorganisms and food in relation to food’ processing, food spoilage, food borne disease and their prevention
Dairy Microbiology: Deals with production and maintenance in quality control of dairy products.
Aquatic Microbiology: Study of microorganisms found in fresh estuarine and marine waters.
Air Microbiology: Deals with the role of aerospora in contamination and spoilage of food and dissemination of plant and animal diseases through air.
Exomicrobiology: Deals with exploration for microbial life in outer space.
Medical Microbiology: Causative agents of disease, diagnostic procedure for identification of causative agents, preventive measures.
Immunology: Deals with the immune system that protects against infection and to study serology reactions.
Public Health Microbiology: Concerns with monitoring, control and spread of diseases in communities.
Biotechnology: Scientific manipulation of living organisms especially at molecular and genetic level to produce useful products.