|Description:||This image depicts two test tubes each having been filled with O/F glucose (dextrose) medium, and inoculated with an unknown fermentative bacterial organism. O/F glucose medium consists of agar, glucose, peptone and a pH indicator. Mineral oil had been added to the tube on the right in order to prevent air from interacting with the medium underneath.|
The organism can be identified as fermentative, for in both test tubes the change in color of the pH indicator to a yellow color, means that both media had been changed to an acidic environment through the metabolism of the glucose in the medium. This was accomplished in either tube, for fermentation does not require the presence of oxygen.