LumiMARA ecotoxicity test

LumiMARA uses the reduction in light output by 11 luminescent species of  marine and freshwater bacteria to give a measure of toxicity. It offers a more genetically diverse alternative to ecotoxicity testing using a single luminescent strain of bacteria, and includes a strain of Aliibrio fischeri (previously known as Vibrio fischeri) equivalent to that referenced in ISO 11348-3. We offer a testing services and supply kits.

Bacteria have a number of benefits for ecotoxicity testing compared to higher order organisms:

1. Convenient format: bacteria are small and easy to handle in large numbers, so testing can be carried out in a test tube or microtiter plate.
2. Fast: bacteria grow and respond quickly to the presence of toxins, so test results can be obtained quickly.
3. No ethical issues: testing with microorganisms has none of the ethical issues associated with testing with higher order organisms such as fish.

NCIMB's LumiMARA ecotoxicology assay makes use of the genetic diversity of bacteria and the ease with which they can be handled, to take the concept of the microbial bioassay a step beyond single species testing.

Ecotoxicity testing using bacteria is generally based around assessment of the acute toxicity response of a single strain of Aliivibrio fischeri whereas  LumiMARA uses 11 strains and includes both marine and freshwater bacteria.

Data from previous work illustrates the benefit of using the multispecies LumiMARA test in comparison to testing using the single species of A. fischeri specified in the ISO standard.

When the 11 different species within the test are exposed to the sample they display a range of different responses. The results obtained can be analysed in relation to the most sensitive strain within the test, or the mean result of all strains.

The chart below shows the toxicity response of the A. fischeri strain compared to the response of the most sensitive strain within the LumiMARA test and the overall LumiMARA result.

It shows that in some cases, testing with A. fischeri alone shows little or no toxic effect when both the most sensitive strain and the mean result reveal high levels of toxicity.