Bacillus Badius

1212 WordsMay 10, 20135 Pages
The Identification of Bacillus Badius [pic] Hannah Melanchuk Dr. Robert Suran May 1 2013 Microbiology Abstract Over a three week time span I was able to successfully identify an unknown microorganism by combining the results of several tests. The first test was the Gram stain test which showed the microorganism was Gram positive and rod shaped. Using an Unknown Identification Flowchart, I proceeded to inoculate a Starch plate. In week 2, I analyzed the Starch plate and was able to determine that the results for Starch Hydrolysis were negative due to the dark color. Next, I inoculated Simmons Citrate Agar slants. By week 3 I was able to analyze the Citrate Agar, which tested negative…show more content…
The decolorized Gram negative cells are stained pink. With the results from the Gram stain I was able to follow the “Unknown Identification Flowchart” to the next step, which was to prepare for the Starch Hydrolysis Test by inoculating a starch plate. Starch is a polysaccharide made up of glucose molecules. Some bacteria have an enzyme called amylase which breaks starch down into glucose subunits. The Starch Hydrolysis test is used to determine the production of amylase. Iodine, which is the mordant used in Gram staining, is used in this test to detect the presence of starch. In order to do the Starch Hydrolysis Test I first inoculated a starch plate by using aseptic technique. I streaked the middle of the starch plate with the bacteria into a single line. Then, I let it incubate overnight at 37°C. In week 2, after I added several drops of Gram’s iodine to the starch plate it was ready to be analyzed for starch hydrolysis. The iodine complexes with starch to form a blue-black color in the culture. Clear halos surrounding colonies is the result of their ability to digest the starch due to the presence of amylase. With the results of the Starch Hydrolysis Test I preceded to the final test which is the Citrate Test. Using aseptic technique, I streaked the organism onto the surface of the Simmons’ citrate slant and let it incubate overnight at 37°C. The Citrate Test determines if the organism is able to
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