What is the purpose of agar in media?
Check:
http://en.wikipedia.org/wiki/Agar_plate
to solidify the media in order to obtain a pure colony
The purpose of agar in media is to solidify it and provide a stable surface for the growth of microorganisms, such as bacteria and fungi. Agar is a gelatinous substance derived from seaweed, which is widely used in microbiology laboratories.
To understand why agar is used in media, it is important to know how agar works. Agar is a polymer that forms a gel-like matrix when dissolved in hot water and then cooled. This property allows it to create a solid substrate suitable for microbial growth.
When preparing agar media, agar powder is mixed with other ingredients like nutrients, salts, and sometimes blood or other supplements, depending on the purpose of the medium. The mixture is then heated to dissolve the agar, sterilized to kill any contaminants, and poured into petri dishes or test tubes. As the agar cools, it solidifies into a gel, providing a solid surface for microorganisms to grow on.
The use of agar in media brings several advantages. It provides a consistent texture that allows for uniform distribution of microorganisms. Agar also has a low nutrient content, reducing the potential interference with microbial growth while still providing essential substances for their survival. Furthermore, agar is not broken down by most microorganisms, ensuring the stability of the medium over time.
Overall, agar is a crucial component in microbiology laboratories as it provides a solid foundation for the cultivation, isolation, and identification of microorganisms.