Question

a. What is the purpose of Sodium Thioglycollate inside the FTM?

b. What is the purpose of Resazurin inside the FTM?

c. What is the purpose of Agar inside the FTM?

Answer 1

a. During preparation of Fluid Thioglycollate Media, often harmful compouns such as peroxides are formed from the reaction of molecular oxygen from the environment which may be very lethal to the microorganisms.The purpose of Sodium Thioglycollate inside the Fluid Thioglycollate Media is to act as a reducing agent to maintain the low oxygen tension. This is accomplished by removal of molecular oxygen from the environment and converting the oxygen into water. This in turn prevents the formation of peroxides and hence protects the microorganisms.

b. Resazurin acts as an oxygen indicator inside the FTM. It drives the colour change of the medium to pink, thereby suggesting that oxidation has occured.

c. The purpose of Agar inside the FTM is to slow down the rate of oxygen diffusion into the media. Agar in addition aslo acts as a gelling agent in the media.