Catalase Lab Report

6. Casein Hydrolysis: This experiment tested for the presence of the enzyme Caseinase, using a skim milk agar medium. Casein was used to detect the enzyme. The bacteria were added to the starch agar medium then placed in an incubator at 37 degrees Celsius for 48 hours. The hydrolysis of casein formed a clear halo around the bacteria growth. It was a negative test if no clear halo formed.

7. Catalase: This experiment tested for the presence of the enzyme Catalase, and determine the morphology of the unknown bacteria. The bacteria were streaked on a plate of nutrient agar and incubated at 37-degree Celsius. After incubation, several drops of hydrogen peroxide were added to the colony. The formation of gas bubbles is a positive test for catalase.
A negative test resulted in no gas bubbles.

8. Gram Stain: A gram stain test was used to determine the morphology classification of the unknown bacteria. Bacteria from the broth was added to a glass strip. Crystal violate was dropped on the strip as the primary stain. Then the bacteria were dyed with grams iodine as the mordant. Ethanol acetone was used as a decolorizer to take out crystal violet on gram positive bacteria. Safranin was used to counterstain for gram positive bacteria. The bacteria were then placed under a lens to determine the morphology as coccus, bacillus, or spiral.