MRS Broth powder contains peptone and glucose. These ingredients supply nitrogen, carbon and other elements necessary for growth. Polysorbate 80, acetate, magnesium and manganese provide growth factors for culturing a variety of lactobacilli. The above ingredients may inhibit the growth of some organisms other than lactobacilli.
Yeast extract and meat extract present in MRS Broth provide sources of carbon, nitrogen, and vitamins for general bacterial growth. The yeast extract also contains vitamins and amino acids specifically required by Lactobacilli.
Polysorbate 80 is a surfactant which assists in nutrient uptake by Lactobacilli. Magnesium sulfate and manganese sulfate provide cations used in metabolism.
Procedure:
Prepare 1 liter medium with 54.25g MRS Broth Powder and add 1mL of Tween 80 before autoclaving.
Composition:(In 54.25g MRS Broth/1L H2O)
Peptone : 20g
Glucose : 20g
Yeast Extract : 5g
Sodium Acetate : 5g
Ammonium Citrate : 2g
Dipotassium Hydrogen Phosphate : 2g
Magnesium Sulphate : 0.2g
Manganese Sulphate : 0.05g
Tween 80 : 1mL(additionally add)