3.9.2: Starch Hydrolysis Test Activity

In this activity you will test two bacterial samples. Label each plate with the sample it is to be inoculated with.

1. Turn on the Bunsen burner and sterilize the inoculating loop by passing it through the flame of the burner.
2. Obtain a bacterial culture. Remove the cap. Pass the mouth of the tube through the flame of the Bunsen burner.
3. Insert the loop into the tube to acquire a sample of the bacterium.
4. Pass the tube through the flame of the Bunsen burner and recap the test tube, and return the tube to the test tube rack.
5. Aseptically transfer the sample of bacteria to the surface of the starch agar plate, introduce the sample by streaking back and forth in the center of the plate to form a broad streak down the center of the surface of the plate.
6. Sterilize the inoculating loop by flaming the loop in the flame of the Bunsen burner.
7. Invert your freshly streaked plate to prevent condensation from raining down on the surface of the agar. Repeat steps 1 - 7 for the second bacterial species and starch agar plate to be inoculated.
8. Incubate the plates in an inverted position at 37°C for 24 hours.
9. After 24 hours apply enough iodine to cover the surface of the plate. Observe the plate and record your results.

In the table below write the name of the species tested and the results for each of the tests performed.

Experimental Results

Bacterial Species	Appearance of media following incubation	Starch Hydrolysis Test Results

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