Unknown Bacteria Lab Report

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Introduction The main purpose of this lab was to identify unknown bacteria, every student got different organisms. By using different types of procedures, we obtain results in order to classify the bacteria as gram positive (+) or gram (-) and from there, continue with the processes ending with the name of the bacteria. All the material including a flow chart was provided from the instructor.
Methods
It took about two weeks of analysis and observation in order to identify every result of each test. The first part of this process was the Gram stain in order to identify whether if the bacteria was gram positive or gram negative, the primary stain is where the Crystal violet is used since is a small molecule it enter in to the cell wall, after …show more content…

The main purpose of this test is to determine if the bacteria have the enzyme citrate. According to the Microbiology Laboratory Theory & Application, Citrate Utilization test tells the ability of an organism to use citrate as their sole carbon source to perform citrate fermentation. In this test, Simmons citrate tubes which are green, were exposed with my bacteria. After inoculation for a period of 48 hours, we obtain results if the slant change in color from green to blue or if there is growth that means that citrate is present and obviously the results are positive but, if there is no change in color and no growth this means that the result is negative and citrate is absent. In my case the tube change in color from green to blue, obtaining a positive …show more content…

The objective of this test is to determine if the bacteria produces mixed acid fermentation or acetoin. In the Microbiology Laboratory Theory & Application states that the MR test identifies organism perform a mixed acid fermentation and produce stable acid, in the other hand VP is used to identify organisms that perform 2,3 butanediol fermentation. For this test, we need a broth with our culture which is the unknown bacteria, after 48 hours of inoculation we can continue with the procedure. I transfer almost half of my broth with the bacteria carefully with a pipette to a tube ending with two tubes with culture, then for the MR I added 3 drops of methyl red reagent. On the VP, I added first 15 drops of reagent A then I added 5 drops of reagent B. If for the MR the results are immediately which means turns red immediately this means that MR is positive and VP is negative, if VP changes in about 60 minutes to red and MR stays the same this means that MR is negative and VP is positive. For my bacteria, I got MR positive since the color changed

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