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Microbiology: Laboratory Theory & Application, Brief 3rd Edition

Microbiology: Laboratory Theory & Application, Brief (3rd Edition)

Book Edition3rd Edition
Author(s)Leboffe, Pierce
ISBN9781617314773
PublisherMorton Publishing
SubjectBiology
Section 5-1: Oxidation-Fermentation Test
Observations and Interpretations
Section 5-2: Phenol Red Fermentation Broth
Observations and Interpretations
Section 5-3: Methyl Red and Voges-Proskauer Tests
Observations and Interpretations
Section 5-4: Catalase Test
Observations and Interpretations
Section 5-5: Oxidase Test
Observations and Interpretations
Section 5-6: Nitrate Reduction Test
Observations and Interpretations
Section 5-7: Citrate Utilization Test
Observations and Interpretations
Section 5-8: Amino Acid Decarboxylation(Decarboxylation Tests)
Observations and Interpretations
Section 5-10: Starch Hydrolysis (Amylase Test)
Observations and Interpretations
Section 5-11: DNA Hydrolysis (DNase Test)
Observations and Interpretations
Section 5-12: Lipid Hydrolysis (Lipase Test)
Observations and Interpretations
Section 5-13: Casein Hydrolysis (Casease Test)
Casein Hydrolysis (Casease Test)
Section 5-14: Gelatin Hydrolysis (Gelatinase Test)
Gelatin Hydrolysis (Gelatinase Test)
Section 5-15: Urea Hydrolysis (Urease Test)
Section 5-18: SIM Medium: Determination of Sulfur Reduction, INdole Production, and Motility
Observations and Interpretations
Section 5-19: Triple Sugar Iron Agar/Kligler Iron Agar
Observations and Interpretations
Section 5-20: Bacitracin, Novobiocin, and Optochin Susceptibility Tests
Observations and Interpretations
Section 5-21: Blood Agar
Observations and Interpretations
Section 5-22: CAMP Test
Observations and Interpretations
Section 5-23: Coagulase and Clumping Factor Tests
Observations and Interpretations
Section 5-24: Motility Agar
Observations and Interpretations

Chapter 5, Section 5-1, Observations and Interpretations, Exercise 1

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Here is a tip:

Bromothymol blue dye is used as an indicator for O-F test.

Explanation

  • Uninoculated test tube gives green color as the medium is neutral, and the color of the bromothymol blue dye remains unchanged.
  • Escherichia coli are fermenters that produce an acid end-product, which changes the pH [potential of hydrogen] of the medium and turns the color of the bromothymol dye into yellow.
  • Kocuria rosea are oxidative bacteria that oxidize sugar in the presence of oxygen only to produce a yellow color.
  • Alcaligenes faecalis are non-saccharolytic bacteria. They are not able to metabolize carbohydrates present in the medium, and the color of media in both aerobic or anaerobic conditions is green.

Verified Answer

  • The uninoculated tube was marked as U, and it showed green color in both aerobic and anaerobic media. This implies that no sugar metabolism has occurred in this tube.
  • Tube inoculated with Escherichia coli showed yellow color in both anaerobic and aerobic media. The tube was marked as F, and the organism showed a fermentation reaction.
  • Tube inoculated with Kocuria rosea showed green color in anaerobic medium and yellow color in aerobic medium. The tube was marked as O, and the organism showed oxidation reaction.
  • Tube inoculated with Alcaligenes faecalis showed green color in anaerobic medium and blue color on the surface of aerobic medium. Tube was marked as N, and the organism showed no carbohydrate metabolism.
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