Lab report isolation and identification of unknown bacteria

Due to the building of acid during fermentation, the pH falls.

identification of unknown bacteria lab quizlet

Once a pinch zinc was added to the tube it immediately turned red which means it produced acid and that is a negative reaction.

Firstly, the Gram positive unknown was rod shape.

unknown bacteria lab report gram positive

The enzyme catalase is present in most cytochrome containing aerobic and facultative anaerobic bacteria. Gelatin deeps contain the substrate gelatin, which is a protein produced by the hydrolysis of collagen. Using a sterile inoculating loop a few drops of Proteus vulgaris was taken placed in an Urea broth tube as well as a Mannitol broth tube.

microbiology unknown lab report pseudomonas aeruginosa

No difficult problems occurred with the identification of B. Thus this enzyme is a good indicator of the pathogenic potential of S.

Microbiology unknown lab report staphylococcus aureus

Alpha-amylase 1,4 alpha D-Glucan-glucanohydrolase acts upon large polymers of starch at internal bonds and cleaves them to short glucose polymers. After many contaminated gram stains the gram negative was given by the instructor in a test tube. Once a pinch zinc was added to the tube it immediately turned red which means it produced acid and that is a negative reaction. The small amount of acid produced in the slant of the tube during glucose fermentation oxidizes rapidly, causing the medium to remain orange red or revert to an alkaline pH. Finally a clear gram negative with rods has appeared on the slide. A positive citrate test ruled out P. Bacterial alpha-amylase is particularly suited for industrial usage since it is inexpensive and isothermally stable. This deduction was reached with several bits of evidence. Gelatin deeps contain the substrate gelatin, which is a protein produced by the hydrolysis of collagen. A negative casein test removed S. Starch agar is a simple nutritive medium with starch added.

The absence of coagulation after 24 hours of incubation is a negative result, indicative of an avirulent strain. Glenview, IL, The media is checked over a period of about a week after inoculation and incubation at room temperature, for gelatinase activity.

Microbiology lab identification of unknown bacteria

Louis Community college at Meramec. This is indicated by the change in colour of the medium from orange red to deep red. The second gram stain came out much more clear and had better result. The presence of urease is detectable when the organisms are grown in a urea broth medium containing the pH indicator phenol red. Prokaryotes move by means of propeller-like flagella unique to bacteria or by special fibrils that produce a gliding form of motility. Amylases can be derived from a variety of sources. A negative urea test removed S. This left only P. Organisms which hydrolyze gelatin will cause the gelatin to liquefy. A positive result is indicated by diffuse or cloudy growth mainly at the top and bottom of the stabbed region. Organisms which produce the enzyme break down the hydrogen peroxide, and the resulting O2 production produces bubbles in the reagent drop, indicating a positive test. This method uses N,N-dimethyl-p-phenylenediamine oxalate in which all Staphylococci were oxidase negative.

To enhance the alkaline condition of the slant, free exchange of air must be permitted by closing the tube cap loosely.

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Example of Microbiology Unknown Lab Report