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Scientists Using Genetic Material of a Bacterium Against Some Pollutants

Scientists are making strides in using the environment to fight pollution. This week, researchers report on developments involving a naturally occuring bacterium that detoxifies harmful ground water pollutants.

In an article in the journal Science, researchers report identifying all of the genes that make up the bacterium, Dehalicoccoides, or coccoides for short.

Coccoides has a fondness for PCE and TCE, two chlorinated solvents that are a harmful byproduct of drying cleaning and the manufacture of computer chips. The bacterium ingests the solvents and produces a non-toxic byproduct, ethene.

The organism has the potential to clean up pollution in a wide variety of settings. The problem is it only grows in a very specialized setting that's even hard to produce in the laboratory, according to microbiologist Rehkha Seshadri.

"You add hydrogen, you add chlorinated compounds, you add carbon sources, and even then it was pretty hard to get this organism to grow," she explains. "So, looking at the whole picture now, which having the whole genome sequence allows us to do, you can sort of reconstruct what are the missing nutrients, if you will, that allow this organism to grow."

Ms. Seshadri led a team of investigators that mapped the genetic sequence of coccoides. They found 17 enzymes that do nothing but gobble up PCE's and TCE's.

Ms. Seshadri says the evidence suggests the microbes mutated rapidly when PCE's and TCE's became more prevelant in the environment in the last 30 or 40 years.

"So, the speculation, therefore, is that these organisms were probably more versatile in their metabolic activity back then," she adds. "But they have evolved or streamlined their metabolism probably because of the abundance of these compounds in the environment."

By understanding better how coccoides evolved to neutralize pollution-causing compounds, scientists hope to develop this trait in bacteria that grow more readily at other pollution sites.