Unable to read the Gram Stain at first it was later confirmed that Unknown #7 was a gram negative bacteria. When introduced to Starch Unknown #7 produced no zone of clearing showing that it did not contain the enzyme amylase. When introduced to the Lipid Unknown #7 did produce a zone of clearing indicating that it did contain the enzyme lipase. When introduced to Casein Unknown #7 produced no zone of clearing indicating that it did not contain the enzyme protease. When streaked onto the Gelatin, it remained solid after being incubated for a week.…
pneumoniae does not produce proteases and cannot break down proteins via proteolysis. The fat hydrolysis test was performed to determine whether our bacteria produces lipase, an enzyme that breaks down fat. The fat hydrolysis test was positive, showing K. pneumoniae produces lipase and can break down fats. The indole test was performed to determine if our bacteria can break down tryptophan via the enzyme tryptophanase. Our indole test came back negative, meaning K. pneumoniae does not produce tryptophanase and does not break down tryptophan into indole, ammonia, and pyruvic acid. The urea test was performed to determine if urea is hydrolyzed via the enzyme urease. The urea test was positive, meaning K. pneumoniae produces urease to break down urea. An inoculation onto Kligler’s iron agar determines if an organism can ferment glucose and lactose, it also detects the production of hydrogen sulfide from the breakdown of cysteine. Our Kligler’s iron agar showed acid with gas production, meaning K. pneumoniae fermented both glucose and lactose. The hydrogen sulfide production was negative. A Litmus Milk test is done to determine whether the organism can ferment lactose, digest the milk proteins using proteases, cause the…
The second step is to select the appropriate medium for the specified microbe. In this experiment we will use a liquid broth medium for both cultures. The first is MRS culture medium, which contains polysorbate, acetate, magnesium and manganese to promote growth for lactobacilli. The second is nutrient medium, which is the standard growth medium for most microbes. It contains heat stable digestive products of proteins called peptones and beef broth to promote bacterial growth.…
The purpose of this experiment was to isolate two unknown bacteria and perform a series of selective and differential tests to correctly identify each. After the bacteria was isolated a series of differential and selective tests following the dichotomous key attached were used to identify each bacteria. The Gram-positive bacteria were identified as Staphylococcus aureus with a positive confirmatory test, mannitol salt agar, showing consistent results as well for S. aureus. The Gram-negative bacteria were Pseudomonas aeruginosa with a positive confirmatory…
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.…
Cited: Tortora, G., J. Funke, B.R., Case, C.C. (2010) Microbiology: An Introduction. Tenth Edition. San Francisco, Pearson Benjamin Cummings.…
By doing these tests we will be able to see how the unknown bacteria reacts to certain conditions. If our results of these lab experiments are conclusive then we should be able to determine what our unknown bacteria is.…
Results/Analysis: Gained knowledge about culture media and how to distinguish various types of microbial growth. I also learn about variable conditions that are required for microbial growth, including oxygen levels and temperature.…
The purpose of this lab was to identify two unknown bacteria cultures using various differential tests. The identification of these unknown cultures was accomplished by separating and differentiating possible bacteria based on specific biochemical characteristics. Whether the tests performed identified specific enzymatic reactions or metabolic pathways, each was used in a way to help recognize those specifics and identify the unknown cultures. The differential tests used to identify the unknown cultures were oxidase, catalase, lactose and sucrose fermentation, Kugler/iron agar, nitrate reduction, gelatin hydrolysis, starch hydrolysis, manitol salt, MR-VP, citrate, bile esculin, indole, urease, DNase, and coagulase.…
This experiment is aimed to examine the effects of environment such as Oxygen, Temperature, pH and Osmotic Limitations on the growth of a various kind of bacteria.…
The methyl red test is used to identify enteric bacteria based on glucose metabolism. The Voges-Proskauer test is used to determine if an enteric bacterium produces acidic or neutral end products. First, the medium was inoculated with isolate #1, and incubated at 37◦C for 48 hours. After incubation, 2.5 ml of the medium was transferred to another tube to be used for the Voges-Proskauer test. For the methyl red test, five drops of pH indicator methyl red is added to one of the tubes of medium. After being gently mixed by rolling the tube between the palms of the hands, the results are observed. The MR-VP broth has changed to a yellow-orange color. This is a negative reaction and indicates that pyruvic acid was metabolized to neutral end products. For the Voges-Proskauer test, 10 drops of Barritt’s reagent A is added to the second tube of medium. The culture was shaken, then immediately 10 drops of Barritt’s reagent B was added and it was shaken again. For the next 15 minutes, the culture was shaken every 3-4 minutes. Observations were made at 15 minutes. There was no change in the medium which indicates a negative reaction and also indicates that #1 does not ferment glucose. This is another contradiction of expected results and is contradicted in the next…
This experiment focused on metabolism and biochemical tests. The goal of performing these tests was to differentiate microbes from one another and to compare how metabolic and biochemical processes differ from species to species. The tests performed include: the Fermentation of Sugars Test (sucrose, glucose, and lactose), the Urease Test, the Fermentation of Lactose Test, the Sulfide Indole Mobility (SIM) Test, the Nitrate Reduction Test, the Protein Hydrolysis Test, the Catalase Test, and the Cytochrome Oxidase Test. The microbes that were tested during this lab were: Escherichia coli, Bacillus cereus, the unknown, Proteus vulgaris, Staphylococcus epidermis, Enterobacter aerogenes, the control, and Pseudomonas fluorescens. The microbes tested during these various tests were looking for which would: reduce sulfur/produce sulfate, produce indole, or possess motility, reduce nitrate, and contain protease, catalase and oxidaase.…
The possible identity of the unknown organisms in the mixed culture was limited to bacteria that we had worked with previously in lab. Initially a Gram stain was conducted in order to distinguish the unknown bacterium as a Gram-positive and/or a Gram-negative organism (Lancaster and Bennett, 2012; Kellenberger, 2001). Based upon the results, both Gram-negative and Gram-positive bacteria were observed in the unknown mixed culture (Table 1 and Table 2; Kellenberger, 2001). In order to isolate the two different bacteria, colonies that grew on the MSA were used to inoculate Gram-positive tests, where as MacConkey Agar colonies were used to inoculate Gram-negative tests.…
The first day, materials included 1 Enteropluritube and a sample culture of the unknown Enterobacteriaceae. In order to inoculate the tube, both caps were first removed from either end of the tube. One end of the tube will reveal a short exposed metal tip of a wire that runs through the Enteropluritube. This metal inoculating tip was used to gather one isolated colony of unknown enteric bacteria by touching the end to a colony. The opposite end (the side closest to the glucose test) of the tube was then twisted and pulled out, gradually twisting the wire through the tube, taking care not to pull it out entirely. The wire was then reinserted the same way it was pulled out until the tip came back out the other end. A notch became visible at this end allowing the tip to be snapped off. The snapped of tip was then used to puncture holes in the plastic film on the tube’s side covering the last eight tests (adonitol, lactose, arabinose, sorbitol, Voges-Proskauer, dulcitol/PA, urea, and citrate). Both caps were then replaced, and the tube was incubated for 24 hours at 37 °C (Hébert and Leid and Shand…
What areas around the school appeared to have the most bacteria? The least? Suggest reasons for these findings.…