Characterization of a uranium-tolerant green microalga with high potential for the remediation of metal-polluted waters
Résumé
Uranium (U) pollution of terrestrial and aquatic ecosystems poses a significant threat to the environment and human health because this radionuclide is chemotoxic. Characterization of organisms that tolerate and accumulate U is critical to decipher the mechanisms evolved to cope with the radionuclide and to propose new effective strategies for bioremediation of U-contaminated environments. We isolated a unicellular green microalga that is much more tolerant to U than Chlamydomonas reinhardtii and Chlorella vulgaris. The isolated microalga is able to accumulate U very rapidly and, then, progressively release it into the medium, behaving as an excluder to limit the toxic effects of U. The U-tolerant microalga is able to grow, maintain high photosynthesis and capture 25-55% of U from natural metal-contaminated waters from a reclaimed U mine. The isolated microalga is very promising for the remediation of polluted waters with valorization of algal biomass that accumulates neutral lipids.