What is the purpose of agar?

Agar is used to solidify microbiological media. Having a solid media allows microbiologists to see colonies of bacteria this eases the identification of a single microbe in a mixed population it also allows the selection of variants in a population, it perhaps allows identification from colonial morphology and enumeration of bacteria. Solid media in lawn cultures (spread plates) are used to calculate zones of diffusion/inhibition. Agar is used rather than other substances as reativly few microbes can manufacture the digestive enzymes required to break it down, so the solid media does not become liquid.


It is a solidifying agent.