Phenylalanine agar
From Bugwoodwiki
Purpose
This is a test for phenylalanine deaminase.
Ingredients
| Ingredient | 100 ml | |
|---|---|---|
| Distilled water | 100 ml | |
| Yeast extract | 0.3 g | |
| DL Phenylalanine | 0.2 g | |
| or | ||
| L-Phenylalanine | 0.1 g | |
| Na2HPO4 | 0.1 g | |
| NaCl | 0.5 g | |
| Agar | 1.2 g | |
Instructions
- Bring medium to a boil to dissolve agar.
- Dispense 5 ml each into test tube. Cap the tubes, autoclave, and then slant while still fluid.
- Incubate cultures for 3 days.
- Add a few drops of a 10% ferric chloride solution to the slants. A green color within 5 minutes indicates a positive reaction.
Notes
Expected results
- Phenylalanine deaminase is important for separating Proteus and Providencia (both are strongly positive) from the rest of the Enterobacteriaceae.
- A weak reaction is produced by a few Erwinias.
References
- Fahy, P. C. and Persley, G. J. 1983. Plant bacterial diseases, a diagnostic guide. Academic Press, N.Y., NY. 393 pp. (p. 357).
Contributed by
From the Culture Media for Plant Pathogenic Fungi and Bacteria, University of Massachusetts: Contributed by Robert L. Wick
