Rutgers University scientists discover a bacterium that “breathes” uranium and renders it immobile

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Photo: Bill Gillette, US National Archives and Records Administration Sign at shuttered uranium mill in Rifle, Colorado, warns onlookers of hazards that remain from Cold War era nuclear weapons production.

A team of scientists from Rutgers University have discovered bacteria that “breathe” uranium in soil at an old uranium ore mill in Colorado. The bacterium that breathes uranium comes from a common strain of bacteria known as betaproteobacteria.

Photo: Bill Gillette, US National Archives and Records Administration Sign at shuttered uranium mill in Rifle, Colorado, warns onlookers of hazards that remain from Cold War era nuclear weapons production.
Photo: Bill Gillette, US National Archives and Records Administration
Sign at shuttered uranium mill in Rifle, Colorado, warns onlookers of hazards that remain from Cold War era nuclear weapons production. (http://news.rutgers.edu/research-news/bacteria-could-help-clean-groundwater-contaminated-uranium-ore-processing-rutgers-study-finds/20150614#.VYHnR8-qqkq)

The discovery might potentially hold the key to cleaning up polluted groundwater at sites where uranium ore is processed.

It was known previously that certain microorganisms that cannot breathe oxygen turn to solid iron for respiration and thus decrease the amount of uranium in groundwater; however, scientists had not previously proved that the bacteria were, in fact, “inhaling the uranium”.

“After the newly discovered bacteria interact with uranium compounds in water, the uranium becomes immobile,” said Lee Kerkhof, a professor of marine and coastal science in the School of Environmental and Biological Sciences.

“It is no longer dissolved in the groundwater and therefore can’t contaminate drinking water brought to the surface.”

It is not yet clear how the strain evolved, but Kerkhof believes it has to do with their ability to pass genes to each other. So just like bacteria pick up resistance to things like antibiotics and heavy metal toxicity, this bacterium “picked up a genetic element that’s now allowing it to detoxify uranium, to actually grow on uranium.”

His research team has completed sequencing its genome to support future research into the genetic elements that allow the bacterium to grow on uranium.

According to their research, this discovery has enormous potential application worldwide.

“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,” said Kerkhof.

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

The team’s discovery was published in the 13 April, 2015 issue of Public Library of Science (PLoS) One.

The research is part of a US Department of Energy program to see whether microorganisms can, in fact, lock up uranium and so clean nuclear waste.