Fundamental Research Division
The DRF at the CEA assemble approximately 6,000 scientists since January 2016.
Scientific result | Bioremediation
A new, highly radiotolerant microalga species has
just been isolated from a cooling pool for spent nuclear fuel. After
analyzing the properties of this unique species, researchers now foresee
new strategies for bioremediation .
The newly discovered Coccomyxa actinabiotis, a tiny unicellular alga,
can resist a radiation dose of 20,000 Gy – 2,000 times the lethal human
dose. This is the first eukaryotic organism  known to tolerate absorbing such
high levels of ionizing radiation; until now, only bacteria such as Deinococcus
radiodurans were thought to be capable of this. Researchers from the CEA-iRTSV
in Grenoble have found that a period of two weeks is enough time for Coccomyxa
actinabiotis to return to normal growth, following a radiation dose of 10,000
Gy. Another advantage of this microalga is that it concentrates
radionuclides. This concentration turns out to be 10,000 more radioactive
than the cooling pool water, as this species can accumulate most of the
radionuclides present in the water, i.e. 80 – 100% of the silver, cesium, zinc,
cobalt, uranium and carbon-14. This efficiency is comparable to that of
physico-chemical processes conventionally used for decontamination.
Thus, the basis for a new idea: to exploit this alga for radioactive waste
clean-up within (or exiting) nuclear facilities, or even following
accidental contamination of the environment. The CEA and the Institut
Laue-Langevin have put together a bioreactor pilot study to provide a
proof of concept, which will optimize the bioremediation strategy. In addition,
the researchers hope to elucidate the biochemical and genetic mechanisms that
are used by Coccomyxa actinabiotis to withstand radiation and concentrate
 Eukaryotes are composed of cells with a nucleus surrounded by their own
membrane, within which the DNA is organized into chromosomes. In contrast, the
unicellular prokaryotes (bacteria) lack this nucleus
An extremely radioresistant green eukaryote for radionuclide bio-decontamination in the nuclear industry.
CEA is a French government-funded technological research organisation in four main areas: low-carbon energies, defense and security, information technologies and health technologies. A prominent player in the European Research Area, it is involved in setting up collaborative projects with many partners around the world.