Remel™ Purple Broth Base

Determine the carbohydrate fermentation reactions of microorganisms, especially enteric gram-negative bacilli using Thermo Scientific™ Remel™ Purple Broth Base (Dehydrated). Vera formulated Purple Broth to identify fermentation patterns of bacteria¹. The fermentation properties of bacteria are used to identify microorganisms based on the carbohydrates which are/are not utilized. Addition of selected carbohydrates individually to tubes of Purple Broth basal medium aids in the differentiation of genera and species^2,3.

The peptone in the medium is free of carbohydrates, so on addition of a specific carbohydrate to the base the fermentation reaction can be determined. In order to avoid the depletion of the substrate and reversal of the reaction the concentration of carbohydrate should be 1%. After production of acid from the fermentation of a given carbohydrate there is a development of yellow color. Gas formation can be detected in the Durham tube.

• Easy to interpret -
• Fermentation (acid production)
• Positive test - Yellow color development
• Negative test - Purple color, no color change
• Gas Production -
• Positive test - A bubble or bubbles in the Durham tube
• Negative test - No bubble(s) in the Durham tube

This medium contains gelatin peptone that supplies the amino acids and nitrogenous compounds necessary for bacterial growth. Sodium chloride provides essential electrolytes and maintains osmotic equilibrium. Brom cresol purple is the pH indicator.