UMASS-Amherst researchers report in the latest issue of Nature Nanotechnology that the microorganism Geobacter produces nanowires that transfer electrons via a mechanism not previously observed in biological materials. Electrons move through the protein filaments with a metallic-like conductivity. Networks of the filaments permit Geobacter to produce films that are highly conductive and can transfer electron over cm distances. These findings explain novel environmental properties of Geobacter, such as it ability to grow on iron minerals in soils and sediments where it plays an important role in removing contaminants from groundwater. The metallic-like wires are key to bioenergy applications of Geobacter, which plays an important role in the conversion of wastes to methane in large-scale wastewater digestors, or for generating electricity from wastes in microbial fuel cells, a useful bioenergy strategy for remote locations. Furthermore, the production of a self-sustaining conductive material, grown from inexpensive materials like acetic acid, that is “tunable” by changes in gene expression and also by gate voltage in a transistor configuration opens new possibilities for the generation of environmentally-sustainable nanomaterials and nanoelectronic devices.
