BROMO CRESOL PURPLE BROTH BASE (YEAST FERMENTATION BROTH BASE)

Basal medium (without carbohydrates) are usually employed for studying the carbohydrate utilizing patterns of different organisms by the addition of the desired carbohydrate to the basal medium. Various indicator dyes are used in the basal medium to aid in the visualization of these carbohydrate-utilizing reactions. Bromo Cresol Purple Broth Base is one such basal medium, which employs bromocresol purple as the indicator dye. If the test organism ferments the added carbohydrate, the pH of the medium turns acidic due to the production of acids. The acidity thus produced causes the indicator BCP to change colour from purple to yellow. Air bubbles trapped in the inverted Durhams tubes indicate gas production. Bromo Cresol Purple Broth Base is recommended by APHA for studying fermentation of carbohydrates by pure cultures. Specific carbohydrates are added to the basal medium in a concentration of 0.5-1%. The pattern of fermentation of a battery of carbohydrates is characteristic of a given species or group of species and may be used for their classification or identification.

for di?erentiation of various microorganisms based on their fermentation of speci?c carbohydrates