Methyl Red Voges-Proskauer Test Lab

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Methyl Red Voges-Proskauer Test Lab

Tetia Richardson
Microbiology DL3: Instructor Newton
3/29/2015

PURPOSE
This experiment is designed to become familiar with and perform the MR-VP biochemical test, learn variations in how different organisms metabolize glucose, and to become familiar with and perform the catalase biochemical test.

Materials Used
10% bleach solution
Hydrogen peroxide
Paper towels
Saved E. coli culture
Stock culture: S. epidermidis
Gloves
Candle used for a flame source
Test Tube
Test Tube rack
Pipet
Slide-Box-MBK with blank slides
2 Broth, MR-VP - 5 mL
1 Barritt’s A Reagent - 3 mL in Pipet
1 Barritt’s B Reagent - 3 mL in Pipet
Methyl Red Reagent, 0.1% - 1 mL in Pipet
1 Inoculation Loop,
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Two tubes of MRVP contained E. coli (labeled with a yellow E tag) and the other containing the S. epidermidis after incubation. Only two of these tubes located in the back of the test tube rack were used for Vogues Proskauer Test.

Vogues Proskauer Test: Post-reagent [pic]

Figure 4 shows the two tubes of MRVP containing E. coli and S. epidermidis after incubation and after adding twelve drops of Baritt’s A Reagent to each tube and then adding four drops of Baritt’s B Reagent to each tube. A slight maroon colored band was seen at the top of the S. epidermidis broth which indicated the production of acetoin.

Exercise 2: Catalase Test Results [pic]
[pic]

Figure 5 shows two microscope slides were labeled one E. coli and S. epidermidis. A drop of hydrogen peroxide was added to the smear. Neither the E. Coli or S. epidermidis exhibited a positive test because there was no bubbling or foaming when hydrogen peroxide was added. The image shown in the E.coli slide is the reflection of my lights in my kitchen.

RESULTS/ANALYSIS

What is meant by the term biochemical profile?
“The specific pathways or molecules used by a specific organism comprise its biochemical profile or “fingerprint” and can be used to identify a particular species. Microbiologists have developed series of biochemical tests that use the
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