Genomic Science Program

Highlights of Research Progress

Harvesting Electricity from Aquatic Sediments with Microbial Fuel Cells

Microorganisms known as “electricigens”can efficiently convert organic wastes, renewable biomass, and even mud into electricity and harmless by-products. This capability offers the potential for using microbes (or their components) to generate electricity at low cost while transforming industrial, domestic, and farm wastes. GTL studies are exploring how some microbes accomplish these processes naturally.

The family Geobacteraceae can metabolize organic compounds directly at electrode surfaces, transferring electrons and producing an electrical current. Genome-scale analysis revealed that when G. sulfurreducens grows on electrodes, it produces high levels of a cytochrome (OmcS), displaying it on the outside of the cell. These studies also demonstrated that OmcS is required for power production, which stops when OmcS is removed and resumes when the gene is restored.

GTL investigators are collaborating with the automotive industry to use this information for designing improved microbial fuel cells—microbe-powered batteries that can convert organic matter to electricity. In contrast to commonly considered hydrogen fuel cells requiring highly refined clean fuels, microbial fuel cells can harvest electricity from relatively low-quality, dirty fuels or from biomass without extensive preprocessing. By engineering electrodes that interact better with OmcS or microbes that make more OmcS, increasing the power output of microbial fuel cells and expanding their practical applications is possible. Potential uses range from powering small electronic devices and robots that can “live off the land”to serving as localized domestic power sources for household uses. [Derek Lovley, University of Massachusetts]

Reference

D. R. Bond et al., “Electrode-Reducing Microorganisms that Harvest Energy from Marine Sediments,”Science 295, 483–85 (2002).