Monday, June 22, 2015

Scientists discover bacteria that help with nuclear waste clean-ups

American scientists at Rutgers University have isolated a microorganism that may hold the key to cleaning up polluted groundwater at sites where uranium ore was processed to make nuclear weapons.
In a paper published in the April edition of Public Library of Science (PLoS), the team explains how a soil bacteria found at an old uranium ore mill in Rifle, Colorado, can lock up radioactive element that leached into the soil, polluting water.
The key, they explain, is that this sort of bacteria can breathe either oxygen or uranium to drive the chemical reactions that provide life-giving energy.
Several species of soil bacteria have been touted as potentially useful in the clean-up and stabilisation of nuclear waste, but this is the first time scientists have found one that essentially breathes uranium and renders it immobile.

Lee Kerkhof, professor of marine and coastal sciences. (Photo: courtesy Lee Kerkhof)

“After the newly discovered bacteria interact with uranium compounds in water, the uranium becomes immobile,” Lee Kerkhof, a professor of marine and coastal sciences in the School of Environmental and Biological Sciences, said in a statement. “It is no longer dissolved in the groundwater and therefore can’t contaminate drinking water brought to the surface.”
Breathing uranium is rather rare in the microbial world. Most examples of bacteria able to do so cannot breathe oxygen but often respire compounds based on metals – typically forms of solid iron. Researchers had previously witnessed decreasing concentrations of uranium in groundwater when iron-breathing bacteria were active, but they have yet to show that those iron-breathing bacteria were directly inhaling the uranium.
The expert added he was quite optimistic about the potential application of this finding worldwide. “There is depleted uranium in a lot of armour-piercing munitions,” he said, “so places like the Middle East that are experiencing war could be exposed to high levels of uranium in the groundwater.”
The research is part of a U.S. Department of Energy program to see whether microorganisms can, in fact, lock up uranium and so clean nuclear waste.

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