Study: Bacteria Eats Toxic Waste

BySusan Skiles Luke

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

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

“This is huge,” said Laurie Achenbach, a molecular biologistat SIU. “Think of where most of the toxic waste is — inenvironments where there is no sunlight, like underground orunderwater.”

The bugs target a toxic chemical called perchlorate, a drypowder used in munitions manufacturing that has seeped intogroundwater across the United States.

Unlike Any Other Organism

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

Since the bacteria are found everywhere, they could be put towork at sites by simply stimulating them with the “food” theyneed, Achenbach said, including acetic acid — another word forvinegar.

Professor Brendlyn Faison of Hampton University in Virginia, amember of the American Society for Microbiology, says the practicalimplications are far-reaching.

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

Bacteria as a Tool

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

“We found that it acts like a sponge,” said Coates, anenvironmental microbiologist. The bacteria uses iron to transformhazardous solids that have dissolved in liquid — like uranium — andreverses the process, leaving a harmless solid in a puddle of cleanwater, Coates said.

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

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

The departments of Defense and Energy, which are funding the SIUproject with more than $1 million, could not immediately estimatethe extent of uranium or perchlorate contamination at waste sitesin the United States. The Environmental Protection Agency does nottrack the contaminant, a spokeswoman said.

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