This test determines whether the microbe produces the enzyme phenylalanine deaminase , which is needed for it to use the amino acid phenylalanine as a carbon and energy source for growth.<\/p>\n\n\n\n
If phenylalanine deaminase is present, a degradation product is produced from phenylalanine. The product combines with iron compounds in an acidic environment to produce a green color.<\/p>\n\n\n\n
The medium used is phenylalanine agar<\/a>, a nutrient medium enriched with 0.2% phenylalanine . It is allowed to solidify at a slant.<\/p>\n\n\n\n An inoculum from a pure culture is transferred aseptically to a sterile tube of phenylalanine agar<\/a> to streak the slant. The butt of the tube need not be stabbed. The inoculated tube is incubated at 35-37 C for 24 hours. Then, reagents must be added to allow results to be determined.<\/p>\n\n\n\n After incubation, five drops of 10% ferric chloride<\/a> and five drops of 0.1N HCl<\/a> are added and the tube is gently shaken. A positive result is indicated if a green color develops within five minutes.<\/p>\n\n\n\n 1. Select the phenylalanine agar slant<\/a> medium. <\/p>\n\n\n\n 2. Complete the process of a tube-to-tube aseptic transfer<\/a> to inoculate the medium by streaking the slant.<\/p>\n\n\n\n 3. Place the inoculated tube into the 35-37 C incubator. <\/p>\n\n\n\n 4. Press the New Day button<\/a> to move forward 24 hours.<\/p>\n\n\n\n 5. Incubate this test for only 24 hours. <\/p>\n\n\n\n 6. Retrieve the incubated culture from the incubator.<\/p>\n\n\n\n 7. This is a test that requires addition of reagents to bring about the change in appearance of a positive test. <\/p>\n\n\n\n Select the dropper tool and the appropriate reagent needed from the chemical shelf. Remove the cap lid. For this test, select 10% ferric chloride<\/a>, add it, and then add 0.1N HCl<\/a>. <\/p>\n\n\n\n 8. Observe test result. For this test, the reagent turns the liquid below the slant green when giving positive results. If negative, no color change is observed.<\/p>\n\n\n\n 9. Record test result<\/a>.<\/p>\n\n\n\n Uninoculated:<\/a><\/p>\n\n\n\nHow is the test performed? <\/h3>\n\n\n\n
What reagents are added? <\/h3>\n\n\n\n
Performing this test in the VUMIE Online lab<\/h2>\n\n\n\n
Inoculation of Medium<\/h3>\n\n\n\n
Incubation of the Inoculated Medium<\/h3>\n\n\n\n
Addition of Reagents<\/h3>\n\n\n\n
Determination of Test Results<\/h3>\n\n\n\n