Which technique is used to visualize the results of a catalase test?

The catalase test is performed to identify the presence of the enzyme catalase, which breaks down hydrogen peroxide into water and oxygen. When a drop of hydrogen peroxide is added to a culture suspected of containing catalase, the production of oxygen gas is observed as bubbling or fizzing. This bubbling indicates that catalase is present, as the enzyme catalyzes the conversion of hydrogen peroxide, resulting in the release of oxygen.

This technique is fundamental in microbiology as it helps differentiate between catalase-positive organisms, such as Staphylococcus species, and catalase-negative organisms, such as Streptococcus species, aiding in their identification.

The other techniques listed—color change in a pH indicator, formation of a precipitate, and change in turbidity—are associated with different biochemical tests and do not apply to the catalase test. Specifically, color changes and precipitate formations are more relevant in tests assessing fermentation or specific enzymatic reactions, while turbidity changes pertain to growth measurements in liquid cultures rather than enzymatic activities.