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How do scientists identify bacteria with biochemical tests?

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Microbiology Photomicrograph of *Streptococcus pyogenes*, a bacterium that can cause scarlet fever. (Magnified about 900×.)

Scientists identify bacteria using biochemical tests by evaluating their unique metabolic capabilities and chemical requirements. These tests determine which nutrients a cell can utilize, the specific products generated through its metabolism, its response to particular chemicals, and the presence of characteristic enzymes.12

Laboratory procedures allow for both qualitative and quantitative assessments of these biochemical traits. In modern clinical and research settings, this process is often streamlined through automated instrumentation. Technicians inoculate chambers preloaded with specific substrates, which are then placed into an apparatus that serves as both an incubator and an analyzer. This equipment automatically records the results and can often calculate the accuracy of the identification.1

While genetic analysis is vital for understanding evolutionary relationships, these biochemical profiles remain essential for the classification and identification of bacterial genera and species.2