Identity:

Updates on Bacteria Identification and Bacterial Isolation

[Left, 12 TSB tubes with soil, Center are the TBS tubes w/12 TSA plates, Right are the two TSA source plates of soil]

Today, Matt suggested that I isolate the bacterial colonies in the two TSA plates (one with dilution blank of 1 gram of soil, and another one with 10 grams of soil) and either inoculate in TSB tubes or streak the isolated bacteria in TSA plates. I decided to choose both to see which method worked best, and I streaked a total of 12 TSA plates (6 with 1g of soil and 6 with 10g of soil), and inoculated 12 TSB tubes (6 with 1g of soil and 6 with 10g of soil). I was also told that I should leave the TSA plates and TSB tubes at room temperature. Next Tuesday, I will try a new technique involving oil.

[ The source for the bacterial colonies was from my previous weeks worth experiment where I used dilution blanks to apply 10 grams of soil in one blank, and 1 gram of soil in another. Then I had to streak the samples in two different TSA plates. ]

Necessity of Isolation
Despite the fact that I had to isolate each bacteria colony various times throughout this year, I think that it is important to isolate the bacteria (once present in the TSA plates) to see if there are different types of bacteria present in whatever substance is being tested on. For example, when I saw the result of bacteria growing on a TSA plate for Rid-X, there weren't any different shapes or colors of bacteria and everything looked the same. Ideally, the bacteria in Rid-X should be in unison and not have multiple bacteria. Therefore, it would make sense that in natural sources like soil, there would be a mismatch of bacteria identification because of cross contamination and natural forces. When I saw the different shapes and colors of bacteria growing in the TSA plates for soil, there were just too many to see the sample itself all at once. Isolating each bacterial colony individually was necessary for better and accurate results.

 

[Left, 4 different experiment tubes. Middle, Rid-X (control tube), Right garden soil tube]

 

[Left, Enterobacter aerogenes tube, Right Escherichia coli] 


Results
Since I added 0.02% tetrazolium when I conducted the experiment, if in the following days the experiment changed color to red/pink, then that was an indicator to show that the microbes present began to degrade oil. This caused the chemical indicator to change structure and turn to a red/pink.

Which tube experiments were the ones that turned into red/pink?

Rid-X, because it was already tested to show that it worked, was a tube that changed color (maroon). The Enterobacter aerogenes tube also turned into a light pink color, which is possibility that Rid-X is that bacteria (I concluded that E. aerogenes was in Rid-X). The garden soil tube did not change at all, and the E. coli tube had no change at all. Could this mean that E. coli, the bacteria that I thought was in the soil, is not the correct one? I will see what happens in the next few days and update a last observation to see if the effect of E. Coli and microbes in the garden soil worked or not.