Lab 10/11: Environmental Conditions

Thioglycollate Broth (Above)

Today, we tested our bacteria to figure out whether it uses oxygen, the amount it uses, and if it is tolerant of oxygen. We did this in 2 ways: 1) by inoculating a thioglycollate broth tube, which shows the amount of Oxygen bacteria uses.  2) by putting a sample of our bacteria in the GasPak which makes the environment completely free of O2. In the GasPak, there's an envelope with a paper that indicates whether oxygen is present in the container, or if the container is free of oxygen. You use catalyst called Palladium, which takes out CO2 and replaces it with O2. If there’s O2, the paper turns blue, if there’s no O2, the paper is white. This is how you can tell whether the GasPak is free of O2 or not. We also did the candle in the jar experiment. The burning candle is fueled by the O2 in the environment, but once the cap is put on the jar, all of the oxygen in the jar is used up by the flame and the environment in the jar is free of O2, and CO2 is abundant. Therefore, the flame’s fuel runs out and it dies down.