Faculty Focus: Judy Wall
Raising a stink in Schweitzer Hall
Photo of Judy Wall using an anaerobic chamber. Photo by Nicholas Benner
Desulfovibrio desulfuricans smells like rotten eggs. But there's nothing rotten about this bacteria's potential for cleaning up uranium-contaminated sites and preventing the spread of toxic waste into human water sources.
According to the U.S. Department of Energy (DOE), more than 7,000 U.S. sites are contaminated by uranium and other dangerous wastes primarily due to research, development and testing of nuclear materials before the Cold War ended. The DOE estimates groundwater contamination has already occurred at more than 60 percent of these facilities.
That's why Judy Wall, a professor of biochemistry, has spent the past 26 years researching stinky bacteria. Under the right conditions, D. desulfuricans can reduce uranium from a water-soluble state to an insoluble compound, causing it to separate from the water. The insoluble mineral, uraninite, can then be collected and disposed of more easily.
But bacteria are finicky. Lack of food, fertilizer or water — or having to compete with another organism for energy — can cause stress and may decrease the bacteria's uranium-busting ability. "Before we can harness its power, we've got to know what makes the horse go," says Wall.
To figure out how D. desulfuricans works, Wall and a team of eleven MU researchers are creating genetic mutations and studying enzymes essential to metabolism. This work will help them determine which genes do what and how they respond to stress.
The results are promising. Wall's team already has confirmed the function of an iron-metabolizing gene and identified part of the sulfate-reducing complex, which is critical to how the bacteria get energy. She expects to have completed mutation of 75 percent of the genes within 36 months, which will shed even more light on how D. desulfuricans functions.