What agar gel is used to culture germs?

Answer 1

Agar is a non-nutritive substrate to which nutrients are added . It is used as a solidifying agent in bacterial culture media. Without agar, the medium is liquid while when agar is included, the medium becomes solid (gel-like) soon after cooling.

Unlike liquid media, solid media give the opportunity that bacteria can grow as separated colonies. This helps to identify bacteria because different types of bacteria have different types of colony morphology (shape, color, size, etc).

The first step to check if a specific type of bacteria is present in a specimen is to separate this bacteria from the other types of bacteria present . This is accomplished by cultivating a small portion of the specimen on solid media to give separated colonies.

There are many different types of agar containing media. The most common is nutrient agar as it is considered the least selective and most microbes can grow on it, it is made with beef broth. However, microbiologists will try many things to get fussy bacteria to grow including extract of armadillo! Some media are designed to only allow the growth of certain bacterial species to help microbiologist narrow down their search. These are called selective media. Some media are designed with colour change tests in them so as to allow the further narrowing down of the species of bacteria. These are called differential media.

Answer 2

Agar is famous for its use in petri dishes in the laboratory, but it is commonly used as a food additive. Agar is a thickening agent in candies and jellies. Agar is used as a substitute for Gelatin in vegetarian dishes.