PROCEDURE
OF
DECARBOXYLA
SE TEST
INTRODUCTION
Decarboxylase Test is a biochemical test used
to differentiate between various bacterial
species. It involves the removal of carboxyl
group from amino acids. The reaction is positive
when the medium turns from purple to yellow
indicating the production of alkaline products.
PRINCIPLE
The test is based on the ability of bacteria to
produce decarboxylase enzyme which
removes the carboxyl group from amino
acids. This reaction leads to the production
of alkaline products and changes the pH of
the medium.
PROCEDURE
Inoculate the decarboxylase broth with the
bacterial culture and incubate at 37°C. After
incubation, add a few drops of 1%
bromocresol purple indicator to the medium.
Observe the color change from purple to
yellow. A positive result indicates the
presence of decarboxylase enzyme.
MEDIA
The commonly used media for
decarboxylase test are Moeller's
decarboxylase broth and Christensen's urea
agar. Moeller's broth is used for detecting
decarboxylase activity of amino acids while
Christensen's agar is used for detecting
urease activity.
CONCLUSION
Decarboxylase test is a simple and rapid test used for the identification of
bacterial species. It is a useful tool for differentiating between closely
related bacterial species. The test is widely used in microbiology
laboratories for research and diagnostic purposes.