Hello,
For school I'm doing a project on bacteria and plastic degradation.
For the method I had a R2A agar plate, then I made a suspension of a bacteria and used a sterile cotton swab to put 5 dots of the suspension on the agar plate.
I let this grow for 2 days at 18 degrees celsius (since the bacteria was from a river)
After this I put a Top-agar layer on top of it that contained 0,3 grams BHET (powder) (it was supposed to be 0,014 grams, but i severely miscalculated).
After 17-18 days of incubating i saw halos. Then i put the plates back into the stove to incubate further to see if the halos would get bigger. But to my surprise another 17 days later the halos were gone.
Does anyone have any idea how the halos could disappear?
I do know that BHET crystalizes when the concentration gets too high.
Without having seen the plates it is hard to do anything other than just guess. But two possibilities come to mind, one is that after 17 days (which is a very long time) the halos just diffused away. The second is that the BHET was fully degraded or decomposed by 17 days so there was nothing left to form a halo. k
Did the plates otherwise look the same the second time as the first?
Michael J. Benedik I have two pictures. One with the halo's and one after the 17 days when they seemingly disappeared.
Could it also be that BHET kept crystallizing which caused the halo's to fade?
Even on the original plates it looks as if the halos were really large. My best guess is that with the extra 17 days the halos just took over the plate.
If you are going to repeat, I would start taking pictures much earlier (rather than wait the 17 days even for the first plate). Maybe every 2-3 days and mark the progress over time.
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