The following report will describe both my journey to find my unknown as well as the results that led to my discovery. Before I start, I will say that I am 100% positive that my unknown (which was #31) is none other than Proteus vulgaris. My data and the ensuing results from them simply cannot be disputed. From my first batch of results, Proteus vulgaris reared its head and I had it figured out, but needed the second half to prove my hypothesis correct. It was in fact my discovery that led to the class announcement that the Gelatinase test results for Proteus vulgaris was incorrectly labeled on the table.
The following information will be regarding the data that guaranteed my assumption: Lab Day #1 The first sets of tests for our unknown consisted of whether or not fermentation had occurred in the Phenol Red Broth. The first part of this test was for glucose fermentation with my results being +, which represented acid fermentation based on the yellow broth, and G, which represented gas end-products in the tube. The second part of the test was for lactose fermentation with my results coming back -, indicating that no fermentation occurred as a result of the red broth.
The final part of the Phenol Red Broth tested for sucrose fermentation and my results were were + based on the yellow broth, which meant fermentation with acid had occurred. The next two tests are referred to as MR-VP, but are broken down to represent Methyl Red and Voges Proskauer. My Methyl Red test results were +, which exhibited a red color indicating that there was mixed acid fermentation. The Voges Proskauer test for my unknown came back -, telling me that acetoin was not produced because there was no color change. The final test on this day was the Citrate test.
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Fermentation InvestigationPlanningAs a culture of yeast is merged with solution of sugar, a reaction called fermentation occurs. As products, ethanol and carbon dioxide are produced, in form of liquid and gas respectively. The reaction follows this equation: Glucose solution + Yeast Carbon dioxide + Ethanol + (Energy) And as one of the products is in the form of gas, the volume of the product can ...
My results were a little puzzling as it exhibited slight blue and yellow coloring, but Professor Dovhey-Philips told me that a result coming back VAR was a possibility. This was what led me to Proteus vulgaris being my unknown, with the results from the second day cementing that conclusion in place. Lab Day #2 The second day of tests and results consisted of another six tests, though I didn’t need any more after the concise results I had received from the first day. But I went along with what the experiment called for and started with the Nitrate Reduction test.
My results came back +2, meaning that it was red after adding reagents A&B followed by no color change after the addition of zinc. An explanation of the colors is that nitrate was reduced to non-gaseous nitrogenous compounds (NO3 > NO2 > non-gaseous nitrogenous products).
The next test of the day was for Gelatinase. The results that I received were -, because my gelatin was solid which meant that no gelatinase was present. At first the results puzzled me because the table clearly showed that Proteus vulgaris was supposed to be positive.
Instead of trying to proceed, I questioned the table and was rewarded with the results for the Gelatinase test being reversed. The third test was the Urease test and it came back +. This result led me to deduce that there was rapid urea hydrolysis and the production of urease was strong, both resulting in its pink color. The final three tests for the unknown lab were part of the SIM test, with S standing for sulfur, I standing for indole, and M standing for Motility. My sulfur test was +, because of the black color in the medium that told me sulfur was reduced (H2S production).
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Flame Test Lab Your company has been contracted by Julius and Annette Benetti. They are worried about some abandoned, rusted barrels of chemicals that their daughter found while playing in the vacant lot behind their home. The barrels have begun to leak a colored liquid that flows through their property before emptying into a local sewer. The Benettis want your company to identify the compound in ...
The indole test also came back + based on the red found in the alcohol layer from Kovac’s reagent. This can be explained as tryptophan being broken down into both indole and pyruvic acid. The final test was looking for motility, with my results coming back +. I could tell there was motility because growth from the unknown was radiating outward from the stab line. Based off all of these test results, there was only one bacterium that my unknown could have been. One whiff of it could tell you what my conclusion was: it smells like Proteus vulgaris.