Phenol Red Inulin Broth is recommended for inulin fermentation studies of microorganisms. Positive reaction is indicated by the change in colour of medium to yellow due to acid production as indicated by phenol red, a pH indicator in the medium. Gas production is indicated by the bubbles formation and entrapped in Durhams tube. Streptococcus pneumoniae are known to ferment inulin. It produces acid while does not produce gas. Streptococcus pyogenes do not ferment inulin.
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