This test determines whether the microbe produces 2,3-butanediol as a fermentation product from glucose .<\/p>\n\n\n\n
2,3-butanediol is the end product of a long fermentation pathway, but it is not easily detected. So, the test detects one of the pathway intermediates instead: acetylmethylcarbinol (acetoin) . The production of 2,3-butanediol is thus indirectly detected when the pathway intermediate acetoin reacts with reagents to turn red.<\/p>\n\n\n\n
The medium used is MRVP broth<\/a>, a nutrient broth medium with 0.5% glucose added. This medium is also used for the methyl red test, which determines whether acidic fermentation products result from growth.<\/p>\n\n\n\n An inoculum from a pure culture is transferred aseptically to a sterile tube of MRVP broth<\/a>. The inoculated tube is incubated at 35-37 C for 24 hours.<\/p>\n\n\n\n After incubation, five drops of Barritt’s A<\/a> are added and the tube is shaken gently to mix the ingredients. Then, five drops of Barritt’s B<\/a> are added. The tube is then slanted to allow maximum oxygen exposure to the reaction mixture and allowed to stand for up to 30 minutes. Development of a red color indicates a positive test.<\/p>\n\n\n\n 1. Select the MRVP broth<\/a> medium. <\/p>\n\n\n\n 2. Complete the process of a tube-to-tube aseptic transfer<\/a> to inoculate the medium.<\/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. For this test, select Barritt’s A<\/a> add it, and then add Barritt’s B<\/a>.<\/p>\n\n\n\n 8. Observe test result. For this test, addition of the appropriate reagents makes the culture turn red if the test is positive. If negative, no color change is observed. <\/p>\n\n\n\n 9.\u00a0Record test result<\/a>.<\/p>\n\n\n\n Uninoculated Medium:<\/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