The catalase test is used to detect the presence of catalase enzyme by the decomposition of hydrogen peroxide to release oxygen and water as shown by the following reaction:
2 H2O2 → 2H2O + O2
The catalase reaction is evident by the rapid formation of
bubbles. Hydrogen peroxide is formed by some bacteria as an oxidative end
product of the aerobic breakdown of sugars. If allowed to accumulate, it is
highly toxic to bacteria and can result in cell death. Catalase either
decomposes hydrogen peroxide or oxidises secondary substrates, but it has no
effect on other peroxides.
There are method variations of the catalase test and these include
the slide test method, the tube or bottle method and the agar slant method.
However, the commonly used methods in microbiology laboratories are the tube or
bottle method and the agar slant method because it limits catalase aerosols,
which have been shown to carry viable bacterial cells, that if inhaled could
cause infections as well as contamination in other laboratory work being set up
and work surface areas.
Posted by Dr. Tim Sandle