Catalase Test

 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