Lauryl Sulfate Chromogenic Broth allows the detection of total Coliform and E. coli count at the same time due to the Chromogenic-Fluorogenic Mix. The combination of chromogenic compounds within Lauryl Sulfate Broth provide a double indicator system. This medium contains a phosphate buffer to ensure the high growth of the total number of Coliforms. Lauryl sulfate inhibits gram-positive bacteria. Coliforms and E. coli contain ÃŸ-galactosidase which cleaves the chromogenic substrate. The enzyme which cleaves MUG is highly specific to E. coli, making the simultaneous detection of total Coliforms and E. coli possible. IPTG stimulates the synthesis and increases the activity of ÃŸ-galactosidase. The color change from amber to blue-greenish due to the reaction of the chromogenic substrate indicates the presence of coliforms. Blue fluorescence under UV light allows the rapid detection of E. coli due to the MUG. Tryptophane promotes the indol reaction after adding Kovacs reagent (Cat. 5205). This reactive detects the microorganism capable of cleaving the tryptophane. When E. coli is present in the medium, indol is liberated and reacts with 4-dimethylaminobenzaldehyde to form a dark red dye.
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