Mine Water Bacteria Are Eating Uranium and Locking It Away

Deep in a flooded uranium mine in Germany's Ore Mountains, bacteria are doing something that shouldn't work. Feed them glycerol, a basic fat component, and they pull dissolved uranium out of contaminated water with startling efficiency. After 130 days, 95 percent of it is gone, absorbed into the bacteria's own cell walls.

That alone is remarkable. What floored researchers was the form the uranium took once it got there.

Uranium typically exists in two chemical states, valency 4 or 6, describing how many chemical "hands" an atom uses to bond with others. A third state, pentavalent uranium (valency 5), does exist, but it had always been considered unstable, a fleeting intermediate that wouldn't stick around.

It stuck around. The bacteria produced pentavalent uranium in unusually high proportions, combined with iron and oxygen into a compound called FeU(V)O4, so new it has no common name yet. First documented in 2020 in Croatian soil contaminated by uranium ammunition, that compound had already stayed stable in oxygen for more than 25 years. Nobody knew how it formed in nature, or that bacteria were involved.

Oxygen didn't undo it either. Exposing dried bacterial biomass to open air made FeU(V)O4 levels climb, not drop.

The mechanism behind this stability is still unknown. But somewhere in that mine water, microbes are doing uranium chemistry our models never accounted for.

The Ore Mountains, apparently, have opinions about nuclear remediation.

Read the full story at ScienceDaily, August 9, 2026

Hot Take: Somewhere between radioactive mine water and feeding bacteria glycerol, this story stopped sounding like remediation and started sounding like alchemy.