How Different Substances Effect the Zone of Inhibition in Bacteria

Voiceover

Presenter(s)

Espen Plotkin

Abstract or Description

The purpose of this experiment was to find out what creates the largest zone of inhibition between hand sanitizer, lysol, mouthwash, granite cleaner, and apple cider vinegar. I thought that the hand sanitizer would create the largest zone of inhibition and have the biggest effect, as it is made to deal with a broader variety of bacteria, and the apple cider vinegar would have the slightest effect and create the smallest zone of inhibition because it is not specifically made to kill a large number of bacteria. 

In setting up this experiment, I placed two flasks of nutrient agar into a microwave until the agar melted. I then placed a sample of bacteria called B. Cereus into a 30 degree celsius water bath for ten minutes. After ten minutes, I poured the sample of B. Cerius into both flasks of agar and plated the agar into three different petri dishes. After the agar congealed, I submerged different colored paper disks into each of the substances (hand sanitizer, lysol, mouthwash, granite cleaner, apple cider vinegar, and sterile water), and placed the saturated disks into the petri dishes. I incubated the petri dishes at 30℃ for two days. After the two days, I measured the diameter of the zone of inhibition around the paper disks. The zone of inhibition is the diameter in which bacteria will not grow around the disk. 

The average diameter in millimeters for Lysol was 2 mm, for granite cleaner it was 1.8 mm, for apple cider vinegar it was 1.6 mm, for hand sanitizer it was 0.9 mm, for mouthwash and my control sterile water, it was 0 mm. This was an extremely interesting experiment  and the results were unexpected. The hand sanitizer ended up making one of the smallest zones of inhibition, I thought it would create the largest, and the apple cider vinegar ended up making one of the larger zones of inhibition, I originally thought that it would create one of the smallest zones of inhibition. Research can continue to see which substance creates the largest zone of inhibition for the longest amount of time. 

The purpose of this experiment was to find out what creates the largest zone of inhibition between hand sanitizer, Lysol, mouthwash, granite cleaner, and apple cider vinegar.

In setting up this experiment, I placed two flasks of nutrient agar into a microwave until the agar melted. I then placed a sample of bacteria called B. Cereus into a 30 degree Celsius water bath for ten minutes. Then I poured the sample of B. cereus into both flasks of agar and plated the agar into three different petri dishes. Then, I submerged different colored paper disks into each of the substances, and placed the saturated disks into the petri dishes. I incubated the petri dishes at 30℃ for two days. After the two days, I measured the diameter of the zone of inhibition around the paper disks. The zone of inhibition is the diameter in which bacteria will not grow around the disk. 

The average diameter in millimeters for Lysol was 2 mm, for granite cleaner it was 1.8 mm, for apple cider vinegar it was 1.6 mm, for hand sanitizer it was 0.9 mm, for mouthwash and my control sterile water, it was 0 mm. This was an extremely interesting experiment  and the results were unexpected. The hand sanitizer ended up having one of the smallest zones of inhibition, and apple vinegar had one of the largest zones of inhibition. I thought hand sanitizer would have the largest and apple vinegar would have the smallest.