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NATURESCIENCE

A bacterium could be the solution to nuclear waste

The geobacterias are a genus of proteobacteria which have been found to be very useful when it comes to fighting the contamination of soils by external agents. For example, these bacterias can be used to decontaminate areas where oil spills may have occurred.

They have the ability to oxidize compounds derived from petroleum and other radioactive metals which are found among other materials. Many researches into this are being carried out around the world today trying to discover the possible applications.

Geobacteria or “superbacteria” against Uranium

One of the many investigations focuses in on the capabilities of these microorganisms to clean up the pollution caused by uranium in water. Radioactive cemeteries are often found to be buried many meters underground. They are sealed with concrete walls and are relatively safe. Despite this, there are underground water currents that can reach some of these nuclear cemeteries and filter their waters through these concrete walls.

This could happen in such a way that the uranium could come into contact with the water and seep its way out of the walls. This could cause contamination of the entire surrounding soil.

geobacter sulfurreducens

A team of scientists at Michigan State University has been studying this for years now. They have been looking into how they could improve this geobacteria to make it more resistant and to increase its decontaminating capacity. For this they have genetically modified a new strain of bacteria – “Geobacter sulfurreducens”. They have managed to reinforce the filaments that cover these bacteria (known as pili) to facilitate the absorption of pollutants.

Results of the investigation

There is a wide variety of microorganisms that use these pili to bind with one another. From this binding they then can create a film or biofilm on practically any surface. By reinforcing the pili what is achieved is that this biofilm is stronger and more resistant. The team in the United States was able to verify that the film that makes up the new strain of geobacteria becomes a very effective shield when it comes to neutralizing uranium.

In addition to this, these genetic modifications have led to the increase of the survival of bacteria. Even if the concentration of uranium or radioactive material is high. The process of "decontamination" results in the isolation and immobilization of the uranium which has been dissolved in water. Once isolated, the uranium once again becomes a
solid product. In this way it is possible to significantly reduce water pollution.

bacteria cleaning nuclear waste

According to the scientists, the results so far have been quite encouraging. The biofilm generated by the geobacteria has managed to isolate the uranium in a very effective manner. It absorbs the uranium as if it were a sponge. In addition to this the bacteria that makes up the biofilm hardly suffers from any sort of radioactivity.

Next steps

Once the effectiveness of this newly discovered bacteria and its resistance to radioactivity have been proven, we must continue to develop further. The team now focuses its efforts on studying how bacteria colonizes surfaces to form their biofilms. In this manner, the way in which the geobacteria reproduces to increase their colonies and make them more effective in their fight against nuclear waste could be further improved.

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