Research into microbes that can harvest electricity from waste matter and clean up polluted sites has garnered a major investment from the U.S. Department of Energy. The DOE has awarded $21.8 million over five years to University of Massachusetts Amherst microbiologist Derek Lovley for investigations of the Geobacteraceae, the microbial family with energy-harvesting powers that scientists hope to harness.

Lovley will lead a team of researchers at UMass Amherst and institutions across the country whose aim is to unravel which of Geobacter's genes do what-and in what environments the microbes work best. The scientists will then integrate that information with studies of metabolism and regulation. Research into what gives the organisms their pollution-fighting power will also yield valuable information about what makes these same organisms efficient at conducting electricity, says Lovley.

The project is one of six announced today by the DOE, totaling $92 million, that will be used to fund studies geared toward better understanding microbes and their communities. Over the course of his distinguished career, Lovley has now brought more than $42 million in sponsored research funding to UMass Amherst.

Cleaning up groundwater can be a monstrous task that is often compounded by contaminants steadily leaching from the soil and re-polluting the site. In the search for new, cost-effective methods for combating such contamination, scientists are seeking assistance from microbes that live naturally in soils and waterways. As these microbial communities go about their daily business, some change nearby contaminants into less toxic compounds, or versions that are easier to clean-up.

Members of the microbial family Geobacteraceae often dominate in sites contaminated by uranium, and Lovley has found that the microbes will convert the element to a form that is no longer soluble in groundwater and thus easier to remove. Now he wants to figure out what the optimum conditions are for Geobacter to do their stuff.

"Before, the approach was to dump something into the area of interest and hope that it promoted growth of the organism you wanted," he says. "It's cheap, but often unreliable because we don't know enough about how microorganisms will react to the changes we make."

By figuring out which genes are turned on and off when the microbes are in top cleaning form, Lovley hopes to create a model that can predict how well the different species of Geobacter will grow in different environments. Then, if conditions weren't ideal at a contaminated site-if the microbes needed more nitrogen, for example-it could be added to kick the clean-up into high gear.

These microbes evolved in subsurface environments and they use organic compounds and metals in the soil to make energy, much the way that animals use food and oxygen. It turns out that this quirk in the metabolic pathway that makes these microbes good at cleaning up uranium also makes them good candidates for producing cheap, clean electricity, says Lovley.

Whereas the cells of most creatures use oxygen in their energy-making pathway, Geobacter use metals or minerals such as iron. But these substances often exist in forms that can't be brought into the cell. So the microbes figured out a way of completing some of the steps in their energy-making pathway outside their cells. Lovley and his team recently discovered that species of Geobacter make highly conductive, hairlike structures that extend into their environment. The microbial wires appear to transfer electrons to iron minerals in the soil. Lovley wants to figure out the genes and processes behind these wires, and to incorporate that information into a model as well. Eventually Geobacter could be engineered to efficiently harvest electricity from waste matter or renewable biomass.

Institutions collaborating with Lovley's team are The Institute for Genomic Research, Rockville, Md.; University of Tennessee, Memphis, Tenn.; University of Indiana, Bloomington, Ind.; University of California at San Diego; Genomatica, San Diego, Calif.; and the Argonne National Laboratory in Argonne, Ill.

"These approaches weren't possible before," says Lovley. But advances in technology have changed that, he says. "Now we can run virtual experiments with a computer and decide what will work best-it's changing environmental clean-up from an empirical practice to more of a science."