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Citrate Test Lab Report

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Results Gram Stain: The Gram Stain test was performed on our unknown bacteria F#1729 resulting in in a Gram-negative (-) result meaning that it contained a thin layer of peptidoglycan. This thin outer membrane is composed of lipopolysaccharides and cannot retain the crystal violet iodine used, instead it sloughs off when rinsed with the ethanol alcohol. This leaves the color unretained and the counterstain safranin is absorbed, staining the bacteria pink. Once the slide was ready, we were able to observe the bacterial morphology under the microscope. We identified the bacterial shape as bacillus under 100X magnification with oil immersion. Figure 1: (Pseudomonas Aeruginosa mixture, Under 100X oil immersion) Oxidase Test: To test for the …show more content…

The growth can be observed visually by the color change of the pH indicator. The bacteria is inoculated onto the agar slant and incubated for a period of 24 hours at 37 degrees Celsius. If the results are negative, there is no color change and the medium stays green as shown on Figure 5 (A). However, if there is a color change from green to blue as seen in Figure 5 (B), then the results are positive. After performing the test and incubated the bacteria for 24 hours, we observed that our unknown bacteria showed positive results meaning that it is able to use citrate as its sole source of carbon for …show more content…

The next test that needed to be performed according to the dichotomous key was the oxidase test. If the results of the Oxidase test showed positive results, this would mean that our unknown bacteria could be aerobic and can use oxygen as a terminal electron acceptor in the respiration process because it would contain the cytochrome enzyme. If the results showed negative, our bacteria would not contain the cytochrome enzyme meaning that the bacteria could still be a facultative anaerobe, anaerobic, or aerobic. After the test was performed, the result determined that it was positive suspecting that the bacteria could be P. aeruginosa but further test was needed to be done to be

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