Geobacter sulfurreducens

Geobacter sulfurreducens was the second Geobacter recovered in pure culture, yet the first to have a genetic system and a sequenced genome. It quickly became the model representative of a group known for coupling organic matter degradation to metal reduction and mineralization. Conductivity of type IV pili at unprecedented rates and distances was demonstrated in G. sulfurreducens. The pilus nanowires extend the cell's respiratory chain beyond its envelope to reduce iron oxides to magnetite, which electronically couples Geobacter to syntrophic partners. The pili also trap uranium extracellularly to prevent its permeation in the cell envelope and dynamically disassemble and reassemble to detach the mineral and continue breathing. Cells use the nanowires to grow as electroactive biofilms on electrodes, allowing current harvesting in bioelectrochemical devices. G. sulfurreducens electrified microbiology and set the foundation for the electromicrobiology subfield.