Filamentous Bacteria Act as Living Power Cables

October 30, 2012

Biology

Cable bacteria in the mud of the sea floor (Photo/Mingdong Dong, Jie Song and Nils Risgaard-Petersen/Aarhus University)

The filamentous bacteria Desulfobulbus can function as living power cables in order to transmit electrons thousands of cell lengths away. The bacteria, which are only a few thousandths of a millimeter in length and are invisible to the naked eye, can form a multicellular filament that can transmit electrons across a distance as large as 1 cm under the right conditions.

The scientists published their findings in the journal Nature. This behavior is part ofDesulfobulbus‘ respiration and ingestion process. It was thought to be impossible to move electrons over such enormous biological distances. Scientists had previously discovered inexplicable electric currents along the sea floor. In new experiments, it was revealed that these currents are mediated by multicellular bacteria that act as living power cables.

In a teaspoonful of mud, there may be up to one kilometer’s worth of living power cables. (Credit: Nils Risgaard-Petersen/Aarhus University)

It was surprising to find out that this process was occurring inside a single organism. Cells at the bottom of marine sediments live in a zone that is poor in oxygen but rich in hydrogen sulfide and those at the top live in an area rich in oxygen but poor in hydrogen sulfide. Desulfobulbus forms long chains that transport individual electrons from the bottom to the top, completing a chemical reaction and generating life-sustaining energy.