Little warrior

Scientists discover microbe that degrades a commonly found pollutant

Published: Saturday 30 November 2002

A bacterium that thrives by feeding on a common pollutant may provide a means to help clean up contaminated soil and ground water, scientists reported. The microbe, discovered by Michigan State University researchers, derives energy by degrading trichloroethane (TCA), a widely used industrial solvent found at half of the contaminated us Superfund sites.

It breaks down trichloroethane to a less-toxic substance, said Baolin Sun, a postdoctoral researcher and a co-author of the study. Testing so far has found TCA is the only substance the new bacterium targets, Sun said. Bacteria that consume other toxins have been discovered previously, but the search for one that goes after TCA had been fruitless. "For a while, people didn't think this bug existed. Now we've solved it," Sun said.

Trichloroethane contaminates groundwater and also erodes the ozone layer when released into the atmosphere. The microbe uses hydrogen to produce energy in the absence of oxygen, the researchers report. "The only way we know how to grow the bacteria is to feed it TCA," Michigan state doctoral student Benjamin Griffin said.

The microbe was isolated from sediment dredged from the bottom of New York's Hudson River and also occurs naturally in Michigan's Kalamazoo River. The discovery of the bacterium suggests a strategy for bioremediation of TCA in soils and groundwater, thereby aiding in the attenuation of this ozone-depleting compound.

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