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Intro: Biochemical Tests

Biochemical testing is a powerful tool for the identification of the genus and species of a particular bacterium.

Since each different species of bacterium has a different genetic code, they are able to synthesize different protein enzymes.

These enzymes catalyze all the various chemical reactions of which the organism is capable. Therefore different species of bacteria carry out different and unique sets of biochemical reactions. The types of biochemical reactions each organism undergoes act as a "thumbprint" for its identification.

When identifying a suspected organism, you inoculate a series of differential media. After incubation, you then observe each medium to see if specific end products of metabolism are present. This can be done by adding indicators to the medium that react specifically with the end product being tested, giving some form of visible reaction such as a color change. The results of these tests on the suspected microorganism are then compared to known results for that organism to confirm its identification.