If iodine stains the starch medium blue in the presence of growing bacterial colonies then no amylase is produced by that species. See Starch in Identibacter Interactus. Inoculate starch agar plates by making a short streak with each of several species in different sectors. Incubate at 37 degrees C. Check in 5-7 days for the presence of starch around the streaks by flooding the area with iodine solution. Catalase activity Catalase is an enzyme that catalyzes the breakdown of hydrogen peroxide to water and oxygen gas.
Most aerobic microorganisms produce catalase.
The presence of catalase is important in the prevention of toxic wastes that would kill the cell. The presence of catalase is indicated when hydrogen peroxide is added to a colony or a loopful of bacteria and bubbles of oxygen are released from the surface. See Catalase in Identibacter Interactus. Aseptically pick up some bacterial cells from an agar culture with an inoculating loop. Put a drop of hydrogen peroxide onto the mass of cells adhering to the loop.