Some bacteria produce the enzyme catalase, which is an iron porphyrin protein

This enzyme is responsible for the decomposition of hydrogen peroxide to water and oxygen

 H2O2 CATALASE H2O + O2

  Procedures:

Emulsify about 1 or 2 colonies of Staphylococcus organism from a plate culture with a drop of saline on a slide.

Add a drop of hydrogen peroxide.

Observe for air bubbles 

Observation:

Positive test • presence of air bubbles• Bubbling upon the addition of hydrogen peroxide

is indicative of the presence of catalase for this organism.

• Note, most aerobic organism make catalase.• Differentiates Staphylococcus from Streptococcus

All Staph (+) All Strep (-)

Negative test – no air bubbles