So Many Test Tubes, So Little Time...

I am not getting close to the end of my project. I have completed another four test to the same 9 bacterias, but I have to redo one of the test. Which was caused by, me letting it inoculate for too long. We also decided that the o/f medium (or oxidation fermentation medium) is very unreliable and difficult to read. This has given us the idea of finding a more efficient way of preforming this test. What this test detects is if acid is given off after fermentation or oxidation. This is suppose to allow for a color change to happen in the media, changing it to a yellow rather than the dark green that it began. This is due to a lowered pH after oxidation occurs in the process of inoculation. From my practice doing the test on all the bacterias, I realized that it was very difficult to get a significant amount of bacteria in the test tube, while still trying to follow the directions of how to correctly "stab" the media. This could have been one of the issues because its not given enough bacteria to react to.
The one test I really found interesting was the T.S.I Slants (Triple Sugar Iron Agar). This is another acid test that detects presence of acid and Sodium Thiosulfate (reduced to H2S gas). If positive for the gas the media would change colors from yellow to black (or a very dark red, in my test). The reaction occurs because H2S reacts with ferrous sulfide in order to create the black precipitate that grows mainly from the "butt" of the media in the test tube.

This is an example of a positive reaction for acid from sugar fermentation in the bacteria. What was so interesting about this tube in particular is the fact the the actual media moved that high in the tube. They all started off at the same height and as you can see in the image above, the media completely shifted upward in the tube.

 

These images above are examples of positive reactions for H2S gas. The very first one was the one that I found most fascinating mainly because of the intense color change. Remember, they all started off a yellow color, most similar to the media shown on the far top. 
Well that's pretty much where I am at now, and I just found out that I will doing all these test AGAIN, with 12 different bacteria's. So, wish me luck! :[