• Universitat de València
• Universidad Rey Juan Carlos I

• Myriam Catalá Rodríguez
• Mª Rosa De las Heras González
• Paula Herrero Garretas

Bioassays allow qualitative and quantitative assessment of the toxic substances causing environmental pollution, and have advantages such as their low cost or the possibility of assessing the effects of pollutants over longer periods than traditional chemical analyses. However, systematic assessment of the impact of pollution on the environment or on human or animal health requires bioassays using miniaturisation procedures, known as microbioassays. Microorganisms such as bacteria, protozoa, invertebrates and microalgae can be used in the study of aquatic toxicity in this type of assay, the latter being the most commonly used. However, microbioassays with microalgae are not representative of the terrestrial environment, and require toxic exposure times of between 24 and 72 hours, which is why they are not considered ultra-rapid methods. There is therefore a need for a microbioassay that allows us to obtain an assessment of the toxicity of a water sample in a short time and in a reproducible and effective manner, and the results obtained are, at the same time, representative and extrapolable to terrestrial ecosystems.

Researchers from the Universidad Rey Juan Carlos and the Universitat de València have designed a microbioassay and an ultra-fast kit capable of estimating the environmental toxicity of water samples by using phycobionts isolated from lichens. Phycobionts are one of the few organisms tolerant to total desiccation with the ability to rehydrate and recover their functions quickly. In rehydrating the phycobiont, an intracellular free radical sclerosis occurs, the pattern of which is modified in the presence of environmental pollutants. Changes in the production of free radicals are determined by using a specific fluorescence probe and a fluorimetre. This method makes it possible to detect toxicity before cell death occurs by detecting changes in metabolism due to the interaction of the phycobiont with the toxic material.

The technology is applicable in the fields of biotechnology, the environment, environmental industry and in the ecotoxicological sector. It may be of interest to environmental management companies, air pollution control and reduction companies, water resource management companies, and entities dedicated to environmental quality assessment, research and development.

The main advantages of the technology are:

• Ultra-fast toxicity results, obtained in a few minutes.
• Easily automated bioassay, which allows the analysis of a large number of samples with a small volume per sample.
• Organisms tolerant to desiccation. Ease of packaging and transport.
• Easy implementation of the method, which allows the use of portable fluorimeters for the analysis of samples in situ.
• Great ecological relevance of phycobionts, which makes them useful as a tool for environmental monitoring and follow-up of different habitats.
• Low economic cost of the bioassay.

• Patent applied