The luminescent bacteria test is employed for determining the acute toxicity of waste waters to bacteria, in accordance with the DIN EN ISO 11348-1 and DIN EN ISO 11348-2 norms. In this test, the inhibition of the bioluminescence of the bacterium Vibrio fischeri is measured as endpoint.
The luminescent bacteria are exposed in an incubator under defined conditions to the test substance. Disturbances in the cellular metabolism lead directly to a weaker light emission by Vibrio fischeri, and differences to controls are therefore measurable in a photometer shortly after exposure. After 15 and/or 30 minutes exposure, the dilution step by which the inhibition of luminescence is smaller than 20% can be measured, which counts as the non-toxic dilution of the sample.
The luminescent bacteria test is applied as a screening test for monitoring sewage treatment plant effluents.