Preview

Indole Test Lab Report

Good Essays
Open Document
Open Document
1678 Words
Grammar
Grammar
Plagiarism
Plagiarism
Writing
Writing
Score
Score
Indole Test Lab Report
Citrate Test:
Some bacteria can use citrate as a source of carbon. To test if the unknown bacteria uses citrate as a source of carbon, Simmon’s citrate agar was used as the medium on which the bacteria was grown. The Simmon’s citrate agar consists of sodium citrate as the source of carbon, ammonium dihydrogen phosphate as the source of nitrogen along with pH indicator such as bromothymol blue.
Procedure:
The Citratase activity was detected by inoculating the unknown bacteria on the slant surface of Simmon’s citrate agar. Followed by overnight incubation at 37°C. Day after the slant was observed for a change in color.
Results:
Two results can be acquired in the citrate test, positive and negative. The positive result indicate growth with the
…show more content…
Indole Test:
Procedure:
We obtained a tube of tryptic soy broth (tsb) and inoculated it with our unknown bacteria. Then placed our tube in the incubator at 37 oC and allowed for it to grow overnight; the following day we came back to finish our confirmatory test. To do so, we added 10 drops of Kovac’s reagent to the tube and watched for a color change.
Results:
A positive test, indicated by a red/pink layer, is due to the tryptophan being hydrolyzed producing indole, pyruvic acid, and ammonia. The Kovac’s reagent indicates solely the presence of indole because the bacteria will use the pyruvic acid and ammonia for nutritional needs. A negative test is indicated by the lack of a red/pink color; this indicates that the bacteria does not contain the enzyme tryptophanase, therefore, they cannot hydrolyze tryptophan resulting in the lack of indole production. Once we added the Kovac’s reagent we observed the formation of a red/pink layer indicating that indole was produced.
Confirmatory
…show more content…
Growth indicated that the bacteria grown was gram-negative, whereas no growth indicated that the bacteria grown was gram-positive. Whereas no color change inferred that the bacteria grown can’t ferment lactose whereas color change to pink inferred that the bacteria grown can ferment lactose. The results acquired by our test was positive with color change to pink. Hence the unknown bacteria was gram-negative and can ferment lactose. Amongst Escherichia coli and Proteus vulgaris, the result MacConkey agar confirmed that the unknown bacteria was Escherichia

You May Also Find These Documents Helpful

  • Satisfactory Essays

    In my test the s. epidermidis turned bright red indicating a positive result meaning that it produces a stable acid. The E.coli sample turned orange…

    • 220 Words
    • 1 Page
    Satisfactory Essays
  • Good Essays

    Indole Test Lab Report

    • 1279 Words
    • 6 Pages

    We identified that K. pneumoniae is a facultative anaerobe. When inoculated onto an agar slant, K. pneumoniae took the shape of echinulate. When inoculated onto a nutrient agar plate, we identified that the growth of K. pneumoniae was round and smooth with a convex elevation.…

    • 1279 Words
    • 6 Pages
    Good Essays
  • Better Essays

    Negative Unknown Lab Report

    • 2965 Words
    • 12 Pages

    The citrate test was performed by streaking a Simmons Citrate slant with an inoculating loop. The loop was flamed and a collection of bacteria from the pure culture of unknown number 25 followed. The citrate slant was then inoculated by lightly moving the tube in a swivel pattern to help the loop not touch the walls of the container. The Citrate slant was then incubated for 48 hours in a hot room of 37 degrees Celsius. Observations of any change or growth were properly recoded…

    • 2965 Words
    • 12 Pages
    Better Essays
  • Powerful Essays

    The purpose of the unknown bacteria lab assignment was to select an unknown bacteria culture and, through a series of metabolic tests, identify which bacteria genus resided in the pure culture received. A nutrient broth inoculated with bacterial culture (numbered 45, henceforth referenced as U45) was selected and a streak plate was made to isolate a pure culture for use throughout the assignment.…

    • 1738 Words
    • 7 Pages
    Powerful Essays
  • Powerful Essays

    Unknown report Micro

    • 1261 Words
    • 5 Pages

    The purpose of this lab was to determine the identity of an unknown bacteria slant culture using a series of differential tests. The tests used to identify the unknown bacterial culture included: Gram stain, mannitol salt agar, coagulase tube test, and an antimicrobial susceptibility test. The tests selected were based on the results of a gram stain.…

    • 1261 Words
    • 5 Pages
    Powerful Essays
  • Good Essays

    MicroOrganism

    • 777 Words
    • 4 Pages

    The purpose of this experiment is to distinguish and indentify an unknown bacterium. There are several tests that can help one eliminate and narrow down the options. The most useful test, and the very first one done, is a gram stain. This test will tell whether the bacterium is gram-positive or gram-negative. After the type of gram stain is identified, the tester has a wide array of differentiating tests at their disposal. Based on the results from these tests, and the numerous others that are available, one can accurately establish the identity of an unknown bacterium.…

    • 777 Words
    • 4 Pages
    Good Essays
  • Better Essays

    In this lab experiment we did several test to determine what our unknown bacteria was. To determine this we recorded the results of how the bacteria reacted to different media. Depending on the results of each test we could narrow down the different bacteria to determine what our unknown is. This experiment will also determine if our bacteria is a fermenter of sugars and if it is catalase positive. If the bacteria is a fermenter they will use the sugars to make ATP. If the bacteria is a fermenter of lactose/sucrose the EMB plate we used will “clearly differentiate between the colonies of lactose fermenting and non-fermenting microbes. In the same medium sucrose was also included to differentiate between coliforms that were able to ferment sucrose more rapidly than those that were unable to ferment sucrose” (Cheeptham & Lal, 2007).…

    • 1370 Words
    • 6 Pages
    Better Essays
  • Satisfactory Essays

    Lab 4

    • 890 Words
    • 4 Pages

    Purpose: The purpose of this experiment is to Learn and employ aseptic technique, to become familiar with basic requirements of microbial growth, to learn the basic forms of culture media, and to become familiar with methods used to control microbial growth.…

    • 890 Words
    • 4 Pages
    Satisfactory Essays
  • Better Essays

    Unknown Lab Report

    • 2145 Words
    • 9 Pages

    The oxidase test was performed only on gram (-) bacteria and was used to test for the presence of cytochrome oxidase. Living bacteria were placed on a paper towel and saturated with a chromogenic reducing agent. Within seconds the reagent, acting as an artificial electron acceptor, will turn purple if oxidized cytochrome oxidase is present, indicating a positive test. If no color change is observed, no cytochrome oxidase is present and the test is negative.…

    • 2145 Words
    • 9 Pages
    Better Essays
  • Good Essays

    Unknown Microorganism

    • 1335 Words
    • 6 Pages

    The streak for isolation was chosen to see the formation of the different colonies and to see if the bacteria would cause growth on the plate. After observing the plate, it could be seen that the unknown had growth and formation of colonies. The Gram stain was chosen next to determine if the unknown was gram-negative or gram-positive. After looking at the gram stain under the microscope with the oil immersion it could be determined that the unknown was gram-negative due to the fact that the bacteria was pink in color and rod shaped. After determining the unknown was gram-negative, other bacteria’s were able to be eliminated from the options. The Triple Sugar Iron Test was chosen next because the unknown could be tested for glucose fermentation, lactose fermentation, sucrose fermentation and sulfur reduction. If the organism is able to ferment glucose and lactose and/or sucrose it will turn the medium yellow throughout (Leboffe & Burton 329). When the Triple Sugar Iron Test was complete, it showed a yellow butt, yellow slant and gas production. This determined that the unknown ferments glucose and one or both of the other sugars. The gas was produced by fermentation. The color change in the agar brought the unknown down to two options of unknowns, Escherichia coli or Hafnia alvei. The SIM medium test was chosen next to see sulfur reduction, indole production from tryptophan…

    • 1335 Words
    • 6 Pages
    Good Essays
  • Good Essays

    Erin's Protein Case Study

    • 546 Words
    • 3 Pages

    Explain why Erin’s assumptions about her protein needs are unrealistic based on her current weight.…

    • 546 Words
    • 3 Pages
    Good Essays
  • Better Essays

    Unknown Lab

    • 1989 Words
    • 8 Pages

    Once the colonies were isolated and the appropriate Gram-negative and Gram-positive tests were conducted, the identification of both unknown organism were fairly easy. The results from the Coagulase test, the Oxidase test, and the Nitrate test were used to help identify the unknown Gram-positive bacterium. The coagulase test was negative, therefore of all the possible Gram-positive bacterium the unknown organism could either be Staphylococcus simulans or Micrococcus luteus (Table 3; Lancaster and Bennett, 2012). Next, the Nitrate test was used to differentiate between the two remaining possibilities. Since the unknown Gram-positive bacterium resulted in a negative for Nitrate, the organism was identified as Staphylococcus simulans.…

    • 1989 Words
    • 8 Pages
    Better Essays
  • Good Essays

    Unknown Bacteria

    • 2198 Words
    • 9 Pages

    This was done using an inoculating needle and aseptically transferring the bacteria into a slant of Simmon's citrate agar by stabbing the needle into the butt of the agar, then streaking it across the top of the agar as the needle was pulled out. The tube was then placed in the 37 degrees Celsius incubator for 48 hours, observed for a blue color, then placed back in the incubator for another 5 days and observed again.…

    • 2198 Words
    • 9 Pages
    Good Essays
  • Good Essays

    Buddhism and Daoism

    • 781 Words
    • 4 Pages

    Buddhism and Daoism are both religions of the Chinese people. These are two of many religions of the massive world we live in. each of them are distinctive, but greatly influenced the lives of their followers and the society in which the belief systems are practiced. Buddhists follow the Four Noble Truths and the Taoists follow the Four Major Taoist Principles.…

    • 781 Words
    • 4 Pages
    Good Essays
  • Good Essays

    The Great Gatsby

    • 623 Words
    • 3 Pages

    There are many characteristics that identify Jay Gatsby as a tragic hero. Some of the characteristics of a tragic hero include greatness, a weakness or a flaw, an undeserved fate and a punishment exceeding the crime. Jay Gatsby encompasses all of these characteristics of a tragic hero. Although, the author tries to portray Gatsby as a perfect person, there are still some flaws that are noticeable. Gatsby's great life unwinds with the death of the tragic hero.…

    • 623 Words
    • 3 Pages
    Good Essays