Bacteria's Appetite Might Be Harnessed To Clean Up Uranium Contamination, University Of Missouri Researcher Says

For the past four years, Judy Wall, professor of biochemistry, has studied a species of bacteria with the goal of determining its potential for bioremediation of sites contaminated by uranium spills. Bioremediation is the use of living organisms to reduce or eliminate environmental hazards from toxic chemicals or other wastes. In the United States, radioactive materials, including uranium, contaminate about 40 million tons of soil and debris, enough to fill 17 professional sports stadiums, and 1.7 trillion gallons of groundwater, about four times the daily U.S. water consumption. Her research is funded as part of the U.S. Department of Energy’s Natural and Accelerated Bioremediation Research program.

“This particular bacterium is found virtually everywhere,” Wall said. “What makes it unique and a potential remediator for uranium is how it makes its energy. It doesn’t create its energy through photosynthesis like plants or by burning oxygen like animals. Instead, it makes energy by pushing, or adding, electrons onto other compounds.”

Wall believes this electron transport system could be used for bioremediation. By pushing electrons onto the very soluble but dangerous Uranium VI, a more neutral form — Uranium IV — is created. This form is not soluble and can be more easily contained and filtered from contaminated water.

“If we can use the bacteria occurring naturally at a site, we can reduce the level of disturbance to the environment during cleanup,” she said. “Bioremediation also should provide a cost savings.”

Currently, Wall is working with researchers at the Los Alamos National Laboratory in New Mexico to understand the proteins that deliver the electrons to Uranium VI. The researchers have identified at least one protein in the process, and in the future, they hope to learn how to increase the bacterium’s affinity for uranium and increase its efficiency as a bioremediator.

“Once we’ve determined the genetic pathway, we can begin to examine other factors that might affect the bacterium’s use in bioremediation,” she said. “We’ll need to identify competitors for the electrons, such as other heavy metals, isolate environmental factors that could stop the transport system and determine methods to encourage growth of these helpful bacteria.”