Citrate agar.

Question 1

What is citrate agar?

Answer 1

Citrate agar is a differential and selective media that is mainly used to identify bacteria that can use citrate as their energy source.

Question 2

What is the basis of citrate agar?

Answer 2

The basis of citrate agar is that the media contains citrate, ammonium salts and bromothymol blue. When citrate is metabolised, the ammonium salts break down to ammonia, increasing the alkalinity of the media which is detected by the bromothymol blue indicator, changing the colour from green to blue.