"Microbial fuel cells show promise for conversion of organic wastes and renewable biomass to electricity, but further optimization is required for most applications," says Derek Lovley of the University of Massachusetts in Amherst. Earlier this month, Lovley announced at a meeting that he and his colleagues were able to achieve a 10-fold increase in electrical output by allowing the bacteria in microbial fuel cells to grow on biofilms on the electrodes of a fuel cell.
This week, Gemma Reguera, a researcher in Lovley's lab will present data identifying for the first time how these bacteria are able to transfer electrons through the biofilms to the electrodes.
"Cells at a distance from the anode remained viable with no decrease in the efficiency of current production as the thickness of the biofilm increased. These results are surprising because Geobacter bacteria do not produce soluble molecules or 'shuttles' that could diffuse through the biofilm and transfer electrons from cells onto the anode," says Reguera.
She and her colleagues discovered that the bacteria produce conductive protein filaments, or pili 'nanowires,' to transfer electrons. The finding that pili can extend the distance over which electrons can be transferred suggests additional avenues for genetically engineering the bacteria to further enhance power production.
Researchers from the Universidad Nacional Autonoma de Mexico announce that they have genetically engineered the
Contact: Jim Sliwa
American Society for Microbiology