Phenylalanine Agar Slant


What is this medium used for?


Bacteria are identified based largely on what organic compounds they can break down. The range of compounds used depends on the collection of enzymes a species of bacteria can make. Phenylalanine is an amino acid that some bacteria can use because of an enzyme called phenylalanine deaminase. Phenylalanine agar is thus used to determine whether the microbe can use the amino acid phenylalanine for carbon and energy.



How is phenylalanine deaminase activity determined? 


If phenylalanine can be used, the microbe will accumulate a compound called phenylpyruvate. When the right chemicals are added to the tube, phenylpyruvate is converted to a green compound, indicating a positive test.



What is the content of this medium?  


The medium used is phenylalanine agar, a nutrient medium enriched with 0.2% phenylalanine. It is allowed to solidify at a slant.



How is the test performed?  


For information on how to determine the ability of a microbe to produce the enzyme phenylalanine deaminase, refer to the phenylalanine deaminase test.