Decarboxylation of Amino Acids
- Test that uses Moller's Decarboxylase Base Medium, which contains glucose, the specific amino acid and bromcresol purple as the pH indicator.
- If organism is able to decarboxylate the amino acid (remove a carboxyl group, COOH), it will create amine byproducts that will raise the pH of the medium making it purple.
- Glucose is added to the medium because decarboxylase enzymes are activated at an acidic pH and under anaerobic conditions.
- After inoculation, a layer of mineral oil is added on top of the medium to create an anaerobic environment.
- If fermentation of the glucose takes place (yellow), then an acidic environment is created which can activate the decarboxylase enzyme which will create an alkaline environment.
- Purple starting color → yellow (fermentation, acidic environment to activate decarboxylase) → back to purple = decarboxylation took place (positive result).