Starch, Lipid, Casein, and Motility Results

At the beginning of today's lab, we retrieved our starch, lipid, and casein plates from the incubator along with our motility test slant.

Results:

Above is the result of our starch agar plate test. As you can see, not a whole lot happened here. Our test result is negative, meaning our bacteria cannot produce amylase and therefore, it does not use starch.

This is our skim milk plate that tests whether or not our bacteria uses casein. As you can see, there is a halo around where we streaked the plate. This indicates that our bacteria is able to produce protease and has used up the casein where the halo (clear spot) is. This test is positive!

This is our blue agar dish that tests whether our unknown bacteria can use lipids. Our bacteria has produced a halo around the streak, which indicates complete hydrolysis of triglycerides, positive for lipase production. The bacteria uses lipids, therefore, this test is also positive!

Although it is hard to tell from this picture, the motility slant to the right shows that our bacteria is motile because the bacteria has traveled from the original insertion line from the inoculation needle, causing the agar to appear cloudy.

Today, we also started the gelatin test, the carbohydrates (sucrose, lactose, and glucose) fermentation test, TSIA test, and the litmus milk test. We will let our bacteria grow in the incubator until next lab, when we get to determine the results.