Catalase test is done to detect the presence of catalase enzymes. This enzyme is responsible for protecting bacteria from the accumulation of hydrogen peroxide (H2O2), which can occur during aerobic breakdown of sugars. If allowed to accumulate, it is highly toxic to the organism and can result in death. Catalase will break down H2O2 into water and O2.
Chemical equation for the breakdown of hydrogen peroxide:
2H2O2 → 2H2O + O2
Catalase test can be done by smearing a small amount of the test organism onto the lid of a petri plate/ culture dish. Then add a drop of hydrogen peroxide to the smear. If bubbles can be seen, which is O2, then the test is positive and it can be concluded that the organism makes catalase. A lack of bubbles shows that there is an absence of catalase.
www.usi.edu/Science/biology/ceseeley/cases/catc.html
The positive result is above, top. The negative result is above, below the positive.
http://web.fccj.edu/~lnorman/unknowns.htm?index=2
Bubbling upon the addition of hydrogen peroxide is indicative of the presence of catalase for this organism.
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