Solvents like MTBE are among the most hazardous of pollutants, and the toughest to remove from the environment. And they are almost everywhere: trace amounts can be found in most drinking water. After decades of experimentation and false promises, scientists now think they’ve finally discovered bacteria tough enough to eat these chemicals and turn them into harmless byproducts. “People looked for a long time to find organisms that would efficiently degrade these chemicals,” says Dr. Frank Loffler, a microbiologist at Georgia Tech’s School of Civil and Environmental Engineering. “Now they actually have found them.”
The first big breakthrough came a decade ago, when Perry McCarty of Stanford University and other scientists found two new strains of bacteria that seem to thrive on chlorinated solvents–the world’s most common industrial pollutant, used in glue, paint, aerosol sprays, degreasers and other products. “We thought: my gosh, here’s a bacteria that can only use chlorinated solvents to live on,” says McCarty. The plot thickened last year when samples of TCA, a known carcinogen, were dredged up from the bottom of the Hudson River in New York. Baolin Sun and Jim Tiedje at Michigan State University studied the samples and isolated a new strain of bacteria that “breathes"TCA like other organisms breathe oxygen.
Now that the right bugs are in hand, the next step is to find ways of getting them to proliferate in soil. The bugs are so finicky, scientists have so far had a tough time even making cultures in their labs. The key may lie in analyzing the genomes of these creatures and figuring out what makes them tick. How, for instance, did nature produce microbes with such iron stomachs? They might have gotten a taste for chlorinated solvents from volcanoes and forest fires, but these events occur too rarely to have sustained them for millions of years before the postwar industrial boom. “Everybody’s scratching their heads about this,” says McCarty. If they answer those kind of questions, scientists could eliminate some of the world’s worst industrial byproducts. And Tim McHale could stop scratching the ground outside his window.
