Uranium, a radioactive heavy metal, is typically locked inside minerals in soil. However, mining and other environmental processes can change uranium into forms that dissolve in water. Once it becomes mobile in this way, it can spread through the environment and create problems because of its toxicity.
Researchers at the H e l m h o l t z – Z e n t r u m D r e s d e n – R o s s e n d o r f (HZDR), working with Wismut GmbH and scientists from the University of Granada, have now shown for the first time that bacteria can transform uranium dissolved in water into a stable chemical compound when glycerol is available as a food source.
During this process, the uranium enters a chemical state that had previously been considered only temporary. The findings, published in Nature Communications, could contribute to future research into using bacteria to help clean up environments contaminated with uranium.
In a report obtained from ScienceDaily, bacteria found in soil and water are essential parts of natural ecosystems, and some species are capable of processing substances that can be harmful to humans and other organisms. “There are bacteria that can metabolically utilize the heavy metal, uranium, which is toxic for humans,” says Dr. Evelyn KrawczykBärsch, scientist in HZDR’s Terrestrial Microbiology research group and coauthor of the study.
“Our group’s investigations had already revealed that bacteria can use uranium dissolved in water for their metabolism when they have access to glycerol as a food source.” Glycerol is a basic component of plant and animal fats.
It can also form naturally, for example, when fungi break down wood. The researchers wanted to determine how effectively bacteria could reduce the amount of uranium dissolved in water and identify the chemical forms created as the microbes processed the uranium.
To investigate, the team collected mine water from a flooded uranium mine in the Ore Mountains belonging to Wismut GmbH. In the laboratory, they added a controlled amount of glycerol to samples of the water and kept them in an environment without oxygen.
