Unknown Lab Report Essay

Words: 900
Pages: 4

Name: Danielle

Title: Unknown Lab Report

Introduction: There are many reasons for identifying an unknown bacterium. The reasons range from medical purposes, such as determining if the unknown could cause ailments in living things or knowing what microorganisms are needed to make antibiotics. The experiment was done by applying methods in order to identify an unknown bacterium. An unknown bacterium was handed out by Dr. Honer. The appropriate tests were prepared and applied. The first procedure that was done was the gram stain. Under a microscope, if the gram stain is purple, the bacterium is gram positive, if the stain is red, it is gram negative. The next test was the fermentation tests for glucose, sucrose and
…show more content…
For the gram stain, my organism turned red, meaning that my bacterium was a gram negative and it was also rod shaped. After this test, the possible organisms were: Enterobacter aerogenes, Escherichia coli, Serratia marcescens, Citrobacter freundii, Proteus mirabilis, Pseudomonas aeruginosa, Pseudomonas fluorescens, Salmonella or Shigella. The fermentation tubes were all heterofermented; glucose, sucrose and lactose all turned out to be acid/gas. This narrowed the list down to these possible organisms: Enterobacter aerogenes and Citrobacter freundii. To determine between the two, I did the methyl red test next. The methyl red test was negative, meaning the pH was above 6 and leaving only one organism: Enterobacter aerogenes. To confirm this, the Vogues Proskauer test was performed. The Vogues Proskauer test detects acetoin by oxidation with oxygen in the presence of KOH. These results were positive. The sulfur, indole and motility tests were also confirmations. The bacterium contained no sulfur, did not produce indole and was motile. It