Mixed Unknowns
This report discusses a series of tests along with results done in order to determine two bacteria in a given broth.
For this experiment we were provided with an unknown broth, along with the supplies and media to perform the needed tests that would determine what bacteria the broth contained. We were also provided with a chart of possible bacteria. All tests were preformed with aseptic and sterile techniques.
After being given the broth, using sterile methods I streaked a TSA plate using the quadrant method with the given broth, in hope to grow the bacteria in isolated colonies. TSA plates are a growth media that is used for the general growth of bacteria needed for culturing. It works well because the media is nonselective …show more content…
The gram stain appeared purple so I concluded that bacteria two was gram positive. When observing it under the microscope it appeared to be coccus, in other words circles. They also seemed to be arranged in clusters. I performed the same tests on bacteria two, that I had performed on bacteria one. The first one was the SIM test, my results showed that this bacteria was negative for sulfur reduction, due to the lack of black precipitate. As well as negative for indole, there was no color change. Lastly, it was negative for motility because there was no growth outside of the initial stab. I next performed the phenol red broth fermentation tests. These were only left in the incubators for twenty-four hours because they produced a result right away. Both broths glucose and lactose had changed to the color yellow. This happened because the ph decreased causing the color change from red to yellow. The change of the color from red to yellow indicated acid, however no bubbles had been present in the small tube. So gas is not present. Lastly I did the catalase test, this time not because of its simplicity, but because it would verify what bacteria was present. This time the catalase test was negative. It did not produce any bubbles. This confirmed that bacteria two was enterococcus faecalis, as it was the only negative catalase bacteria on our
This report discusses a series of tests along with results done in order to determine two bacteria in a given broth.
For this experiment we were provided with an unknown broth, along with the supplies and media to perform the needed tests that would determine what bacteria the broth contained. We were also provided with a chart of possible bacteria. All tests were preformed with aseptic and sterile techniques.
After being given the broth, using sterile methods I streaked a TSA plate using the quadrant method with the given broth, in hope to grow the bacteria in isolated colonies. TSA plates are a growth media that is used for the general growth of bacteria needed for culturing. It works well because the media is nonselective …show more content…
The gram stain appeared purple so I concluded that bacteria two was gram positive. When observing it under the microscope it appeared to be coccus, in other words circles. They also seemed to be arranged in clusters. I performed the same tests on bacteria two, that I had performed on bacteria one. The first one was the SIM test, my results showed that this bacteria was negative for sulfur reduction, due to the lack of black precipitate. As well as negative for indole, there was no color change. Lastly, it was negative for motility because there was no growth outside of the initial stab. I next performed the phenol red broth fermentation tests. These were only left in the incubators for twenty-four hours because they produced a result right away. Both broths glucose and lactose had changed to the color yellow. This happened because the ph decreased causing the color change from red to yellow. The change of the color from red to yellow indicated acid, however no bubbles had been present in the small tube. So gas is not present. Lastly I did the catalase test, this time not because of its simplicity, but because it would verify what bacteria was present. This time the catalase test was negative. It did not produce any bubbles. This confirmed that bacteria two was enterococcus faecalis, as it was the only negative catalase bacteria on our