Taming a Little Rotter
One of the things about science that's hard to explain to Congressional committees is that you never can tell what research will turn out to be useful---or why.
Superficially, it wouldn't seem that Dr. Michael Gold, of the Oregon Graduate Institute of Science & Technology, would face that concern. He studies the physiology, biochemistry, and genetics of a common little fungus found worldwide: Phanerochaete chrysosporium, a member of the white-rot family that attacks the lignin in wood.
Research on this organism might have some practical use. A fungus responsible for rot-ting wood deserves understanding. It has its obvious bad sides, from the human perspective, if the wood it rots is in our homes or furnishings. It has its good features as well, since forests would die out if dead wood did not rot and return to the soil for recycling into new trees. Without rot, a walk in the woods would be more like a scramble through the woodpile.
But it turns out that this study-worthy fungus has a few other features. Besides lignin, it metabolizes cellulose (the other major component of wood), creosote (a once-common wood preservative), and oil---among other things. P. chrysosporium has a fair appetite for some nasty pollutants, and is capable of munching up more than one at a time. Given the new and necessary interest in cleaning up the environment, it's a rotter whose time has come.
All the bits of basic understanding that Gold and his team built up over 15 years of studying the fungus now are looking more broadly useful. The researchers found, for example, that the chemical bonds in lignin are very similar to those in the toxic chemical 2,4-dichlorophenol (2,4-DCP), a precursor to dioxin and Agent Orange. Given a meal of 2,4-DCP, their wood-rot fungus turns its once-lethal lunch into harmless carbon dioxide, sodium chloride---common table salt---and water.
To the researchers, that's good, but not good enough. They want to break down the pollutant more efficiently. Using techniques akin to those used to detect drug use in athletes, they analyzed the metabolic byproducts given off by the fungus as it processes the 2,4-DCP. That enabled them eventually to describe the step-by-step, enzyme-by-enzyme digestion of the pollutant.
And that is a first step to engineering a better fungus---or at least one better at cleaning up toxins. Gold's laboratory is now working intensively on the genetics of the wood-rotting fungus, aiming to find genes responsible for cranking out stronger enzymes. They are especially interested in finding how the important genes turn on and off, a necessary step in producing industrial-strength fungus.
Industry is interested, too. The chemical, pulp, and paper producers can envision vats of tamed fungus treating their hazardous wastes before any of them reach the environment. Should any waste spill, the engineered fungus could grow in the soil, eating away at toxic molecules and releasing only carbon dioxide, salt, and water.
So that is the present vision, and a realistic one. But if some fiscal watchdog in Con-gress had been around to question Michael Gold on the day he received his doctorate, he wouldn't have been able to predict such an outcome. Gee, he might have said. I just think wood-rot fungus is interesting. Something might come of it someday, but who knows?
