What are the functions of sugar thioglycollate or cysteine a

What are the functions of sugar, thioglycollate (or cysteine) and resazurin in FTM and Brewer’s anaerobic agar plate?

Solution

FTM is a Fluid Thioglycollate Medium is used for sterility testing of biologicals and for cultivation of anaerobes, aerobes and microaerophils by adding a reducing agent and small amount of sugar.

The composition of FTM g/L

Pancreatic digest of casein 15

Yeast extract 5

Dextrose 5.5

Sodium chloride 2.5

L-Ctsteine 0.5

Sodium thioglycolate 0.5

Resazurin sodium 0.01

Agar 0.75

Dextrose and L-Cysteine provide growth factors necessary for bacterial multiplication and L-Cysteine also allows Clostridium to grow even under aerobic conditions. Resazurin is a oxidation-reduction indicator it turns pink when increased oxidation occurs and colorless when reduced.PH of the medium is 7.1.

Brewer\'s anaerobic agar is used for the isolation and sensitivity testing of facultative, obligate anaerobic, microaerophilic organisms and study of colonial morphology as colonies can readily seen on the light colored agar plate.

Composition: g/L

Protease peptone 10

Casein enzymic hydrolysate 5

Yeast extract 5

Dextrose 10

Sodium chloride 5

Sodium thioglycolate 2

Sodium formaldehyde sulphoxylate 1

Resazurin 0.02

Agar 15

Dextrose is carbohydrate source and provide growth factors.Resazurin imparts pink color to the medium in the presence of oxygen. Sodium thioglycolate provide adequate anaerobiosis to the medium. PH of the medium is 7.2.