The bacterium Geobacter sulfurreducens lives by reducing metals, such as radioactive uranium, rendering them much less soluble and thus less of a threat to the environment. New research published yesterday (September 5) in the Proceedings of the National Academy of Sciences points to how they do it, seemingly without suffering any effects of the toxic substances. They use hair-like filaments known as pili to reduce, or add electrons to, the metal, and depositing the products of the reaction out into the environment via the pili, away from where they could harm the cell.
While it was known that G. sulfurreducens could reduce uranium, understanding how they do it could help researchers use the bacteria more effectively as bioremediators to clean up pollutants from the environment. “Current methods to stimulate the growth of these bacteria in the environment are pretty crude and empirical,” University of Massachusetts Amherst’s Derek Lovley, who recently published on the role of G. sulfurreducens’s pili in electrical conduction, told Nature. “This new mechanism will allow us to better predict how uranium can be depleted.” Furthermore, study author Gemma Reguera of Michigan State University in East Lansing is hopeful that one day the bacteria won’t be necessary at all, and bioremediation technologies could be designed based on the non-living pili. "This would allow us to work in sites where bacteria cannot live," she told Nature.
The authors also plan to see if G. sulfurreducens can also precipitate other toxic elements, such as technetium, plutonium and cobalt.