Culture Media

Culture media or growth media is a liquid or gel support media provided with essential nutrients and growth parameters required for the growth of microorganisms.

  • Culture media are of different types depending on the nutrients they have and the type of microorganisms that grow on them.
  • Growth media are primarily of two types; one for cell culture where specific cell types are grown of specific plants and animals, and another for microbiological culture to support the growth of microorganisms on artificial surfaces.
  • For microbial culture, the most common culture media are agar plates or broth medium. Agar plates are made up of a growth medium containing agar that results in the formation of a gel-like support medium for growth.
  • The broth medium, in turn, is made without any agar, which gives it the consistency of a liquid support medium.
  • Both the agar plates and broth media can be either general media or selective media.
  • General media support the growth of multiple organisms, while selective media allow the selective growth of fastidious organisms that require specific nutrient and environmental requirements.
  • For microorganisms like viruses or parasites, a growth medium containing living cells are required.
  • All culture media have a list of common ingredients like a source of carbon, a source of protein or nitrogen, some salts, and water. 
  • In the case of culture media used for a specific purpose; however, additional ingredients like organic compounds or pH indicators might also be present.
  • The most common general culture media for the isolation of bacteria is the Nutrient Agar that supports the growth of a diverse group of bacteria.
  • Culture media are an important part of routine laboratory research as it allows the artificial culture of microorganisms under laboratory conditions and also helps in isolation and differentiation of different microorganisms.
  • The growth pattern and colony morphology of certain bacteria on certain growth media provide a basis for the identification of the bacteria.
  • Traditionally, this technique was one of the most important methods of identification of microorganisms. It is still employed in many laboratories throughout the world for diagnostic and educational purposes.