Study: Bacteria Eats Toxic Waste

C A R B O N D A L E, Ill., Sept. 28, 2000 -- Researchers at Southern Illinois University say they’ve found a way to turn nearly 40 kinds of common bacteria into toxin eaters that would make hazardous waste sites self-cleaning.

The researchers say the natural bacteria can be nudged into turning a toxic chemical into harmless table salt. And the bacteria can do it all without the sun or the air to give it energy.

“This is huge,” said Laurie Achenbach, a molecular biologist at SIU. “Think of where most of the toxic waste is — in environments where there is no sunlight, like underground or underwater.”

The bugs target a toxic chemical called perchlorate, a dry powder used in munitions manufacturing that has seeped into groundwater across the United States.

Unlike Any Other Organism

But what is perhaps most important, scientists say, is that these bugs do something that no other organism been known to do. While transforming perchlorate to table salt, the bacteria suck out oxygen, generating that precious energy source without the help of sunlight.

Since the bacteria are found everywhere, they could be put to work at sites by simply stimulating them with the “food” they need, Achenbach said, including acetic acid — another word for vinegar.

Professor Brendlyn Faison of Hampton University in Virginia, a member of the American Society for Microbiology, says the practical implications are far-reaching.

“An oxygen source from a waste product in the absence of light suggests a closed system to produce oxygen for humans,” Faison said. “Think of a mine or the space shuttle.”

Bacteria as a Tool

But Achenbach and partner John Coates are focused on the bacteria’s potential uses in cleaning toxins. The researchers now are trying to see if the bacteria can do a similar clean-up job on radioactive metals like uranium.

“We found that it acts like a sponge,” said Coates, an environmental microbiologist. The bacteria uses iron to transform hazardous solids that have dissolved in liquid — like uranium — and reverses the process, leaving a harmless solid in a puddle of clean water, Coates said.

Anna Palmisano, an Energy Department scientist charged with finding new ways to clean up hazardous waste, said she sees the bacteria as a “tool in our larger toolbox” to immobilize hazardous metals like uranium. But that’s not all.

“It’s very versatile,” Palmisano said. “It’s not only a new organism, but it also has a lot of interesting capabilities we can exploit for environmental applications.”

The departments of Defense and Energy, which are funding the SIU project with more than $1 million, could not immediately estimate the extent of uranium or perchlorate contamination at waste sites in the United States. The Environmental Protection Agency does not track the contaminant, a spokeswoman said.

Dolline Hatchett, an Energy Department spokeswoman, said uranium contamination has been found at a majority of the department’s 53 nuclear-weapons waste sites, which the department spent more than $52 billion last year on clean up.