Scientists Find Bacteria Thriving on Uranium

by Monica Joshi

Cockroaches will survive nuclear war. Well, at least they will mutate and adapt really fast. But that's way in the future (hopefully). Currently, even in some of the harshest conditions on earth, organisms have found a way to get by. In underwater volcanoes, for instance, where there is an acidic carbon dioxide environment, football-sized mussels have found a way to grow. It seems like certain microbes are able to live, and even thrive, on environments that are considered dangerous to humans.

Researchers have found a truly remarkable species of bacteria that 'breathes' uranium and thrives in abandoned uranium ore processing sites. This newly discovered strain was found in the soil at an old uranium ore mill in Rifle, Colorado. The mill was once used for nuclear weapons production and the site is still radioactive to date.

As described in PLOS ONE, the bacteria from a class called betaproteobacteria, somehow take a spare electron from the uranium in a process called 'reduction.' It remains unknown whether the resulting uranium is in a state safe enough for humans to interact with. If it turns out that the uranium is safe to interact with, then these bacteria could provide a novel way of clearing up uranium-polluted sites efficiently, so that they are safe for humans.

Professor Lee Kerkhof of Rutgers University said:

“Biology is a way to solve this contamination problem, especially in situations like this where the radionuclides are highly diluted but still present at levels deemed hazardous.”

It's not certain how this type of uranium-eating bacteria evolved to thrive off of radioactive elements. It might be similar to the way that some bacteria develop resistance to antibiotics. This particular species has picked up a genetic element that allows it to detoxify uranium and even grow on it.

This research is part of the U.S. Department of Energy program to see if microorganisms can nibble away at radioactive uranium and make it inert. The department is hoping that this will make any polluted groundwater and well water safe to drink again.

About the resulting bacteria, Kerkhof claims:

"After the newly discovered bacteria interact with uranium compounds in water, the uranium becomes immobile. It is no longer dissolved in the groundwater and, therefore, can't contaminate drinking water brought to the surface."

Kerkhof has concerns regarding the contamination of drinking water. This concern doesn't end with the United States, because if this species can be harnessed to make radioactive zones safe for humans, then there are a lot of places that could benefit from it. In this way, it could be used in other places without waiting for research about the contamination of drinking water.

"There is depleted uranium in a lot of armor-piercing munitions, so places like the Middle East that are experiencing war could be exposed to high levels of uranium in the groundwater."

Scientists are also unsure of the potential impact these organisms could have on the environment, so more research needs to be done on that issue.