The six bacteria used in this lab were, Citrobacter freundii, Bacillus subtillis, Enterobacter aerogenes, Staphylococcus epidermis, Enterococcus durans, and Escherichia coli. Citrobacter freundii is a Gram-negative rod shape bacteria. The MSA plate will grow Citrobacter freundii, Bacillus subtillis, Enterobacter aerogenes and will have a yellow color change while Staphylococcus epidermis will not grow nor have a color change to yellow. The MacConkey agar will have growth with Escherichia coli, Enterococcus durans, but not Staphylococcus epidermis and Bacillus subtilis since it is a Gram-positive. Only Escherichia coli and Enterococcus durans will be the species fermenting. PEA agar isolates Gram-positive species from Gram-negative bacteria. …show more content…
The agent used was called tetramethyl-p-phenylendiamine. When reduced the agent was clear but when oxidized it turned deep purple to a blackish color. This agent (Cytochrome C Oxidase) was the electron donor. This test did not distinguish whether the organism is oxidative or if it fermented. In the Oxidative fermentation tube the media was a differential media that helps determine whether specific bacteria can oxidize or ferment to metabolize glucose. Citrate test checks to see which bacteria could citrate as the only source of carbon. A positive test shows that an alkaline environment ia created and that the pH level rose. The color of the media changed from green to blue if its positive. The Bile Esculin agar test has its medium as selective and differential. Black medium shows a positive result for esculin hydrolysis. In the agar, Gram-positive cannot grow in the presence of bile while certain Gram-negative bacteria can hydrolyze esculin with bile present. MR-VP broth contains glucose and peptone. The enteric bacteria will oxidize glucose for ATP, but there are different fermentative pathways that allow glucose to be fermented. The type that ferments acid would ferment a variety of acids like lactic or acetic
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The unknown bacteria was then tested on multiple selective and differential media. Growth was present on the MacConkey Agar and the colonies were the same color as the plate, which told me my bacteria was gram negative and did not ferment lactose. There was no growth on the Mannitol Salt Agar, and this told me the unknown was not salt tolerant and did not
My bacterium turned out to be gram positive. When conducting these tests, I only had to do the coagulase test and the catalase test because when doing the catalase test, the reaction was that it had bubbled. If it did not bubble, or have a positive reaction, then I would not have had to do the coagulase test. Also, since my bacterium caused a positive catalase test, I only had to do the coagulase test and no other tests. This is because with staphylococcus organisms, these are the only tests
H20 + 2 O2 This experiment will use 1% catalase solution and 3% hydrogen peroxide solution, both diluted into water so the reaction slows down. Temperature will be controlled in this experiment to change the reaction speed of the enzyme and the substrate, this is what the experiment is looking at. The effect of the temperature will be determined by how much gas is released in two minutes, which will change the pressure inside the test tube and will be measured by a gas
1 “substrate” and another “ enzyme.” Instead of using the distilled water, this time you are going to use different pH buffer in the enzyme test tube. In the substrate tube, add 7 mL of distilled water, 0.3 mL of hydrogen peroxide, and 0.2 mL of guaiacol for a total volume of 7.5 mL. For the enzyme tube, instead of distilled water add the pH solution (3) and 1.5 mL of peroxidase which equals a total volume of 7.5 mL. Use the dH2O syringe for our pH solution. To clean the syringe, flush it by drawing 6 mL of distilled water.
Testing for the Presence of Macromolecules in McDonald’s Happy Meals Clayton Wagoner MST Biology White 4 duPont Manual High School Introduction Carbohydrates, lipids, proteins, and nucleic acids are organic molecules found in every living organism. These macromolecules are large carbon based structures. The macromolecules are assembled by joining several smaller units, called monomers, together through a chemical reaction called dehydration synthesis. The resulting polymer can be disassembled through the complementary process called hydrolysis.
It is necessary to understand what each test reveals about the unknown. Citrate tests are performed in order to distinguish between different enteric bacteria by seeing which can use citrate as the sole carbon source. MR/VP are tests that are used to distinguish between different types of fermentation either mixed acid or butanediol and test for the production of acetoin. H2S production is used to determine whether or not the bacteria can produce hydrogen sulfide. Mannitol high salt testing is done in order to determine if the bacteria is salt tolerant and can ferment mannitol.
The tube was placed back in incubation for 96 more hours to observe any more positives. 2.10 Catalase Test A trypticase soy agar plate was used and after incubation, four drops of 3% Hydrogen Peroxide was added to the plate to flow over the bacterial growth. A presence of bubbling was observed. 2.11 Starch Hydrolysis
The Another medium used was MAC, it is used to isolate and differentiate gram-negative organisms and it is a pink, dusty rose color. Lastly, the Citrate Slant is a green color and it was used as a differential test to examine enzymes. The media were inoculated at 37°C for 48 hours, then it was observed to determine the
5 water bath were set up each to10 °C. (5 were used do the experiment faster) 5 cm3 of starch solution were added into the 5 test tubes that were labeled test tubes. Then 5 cm3 of amylase enzyme was added into the other 5 test tubes that were labeled. Put one of the starch solution test tube (preferably the one labeled 1) and one of the test tube containing amylase into the water bath (10 °C).
Joshua Miller 12/18/17 Fermentation Lab report Introduction The term fermentation refers to the chemical breakdown of a substance by bacteria, yeasts, or other microorganisms, typically involving effervescence and the giving off of heat (wikipedia). Sugars are converted to ethyl alcohol when fermentation happens. In this experiment we determined if yeast cells undergo fermentation when placed in a closed flask with no oxygen. Glucose and yeast are mixed together in a closed flask and allowed to incubate for about one hour.
They can also act as a final electron acceptor. Many bacteria can be differentiated and are identified by their capacity to reduce nitrates to nitrites. Most of the bacteria belonging to the family Enterobacteriaceae reduce nitrates . OF test is used to differentiate those organisms that utilize carbohydrates aerobically (Oxidation) such as P. aeruginosa, from those that utilize carbohydrates anaerobically (Fermentation) such as members of the Enterobacteriaaceae. The OF medium contains peptone, test carbohydrate and bromothymol blue as indicator.
Prokaryotic organisms normally have a cytoplasmic membrane, cell wall, and sometimes a capsule. Bacterial cells are most commonly either coccus or bacillus in shape. The cell wall is either Gram positive or Gram negative. When the cell is Gram negative, the cell has an extra layer of lipopolysaccharides. The Gram positive has a thick layer of peptidoglycan.