A tiny bacterium recovered from sediment may power batteries of the future. In a report published today in Nature Biotechnology, researchers describe a primitive microbial fuel cell that can convert simple sugars into electricity with 81 percent efficiency. Unlike previous attempts to manufacture such batteries, the novel design does not require unstable intermediaries to shuttle electrons and thus holds promise for producing energy from sugar-containing waste materials. Swades K. Chaudhuri and Derek R. Lovley of the University of Massachusetts used Rhodoferax ferrireducens, a bacterium first isolated from sediments collected from an aquifer in Virginia, for their bacterial battery. When the researchers exposed R. ferrireducens to a solution of glucose in a chamber containing a graphite electrode they found that when the bacterium fed on the sugar, it transferred electrons directly to the electrode, producing a current. In addition, the sugar-fed R. ferrireducens continued to grow, resulting in stable, long-term power production.? …The prototype fuel cells have such desirable features as the ability to recharge and minimum loss of energy while idling. Perhaps one day electronics will be sold with the caveat “bacteria not included.” —Sarah Graham
The above was in Scientific American in 2003. Here is something more recent from January 2006.
“…The sugar-based microbial fuel cells constructed by Rhodoferax ferrireducens could effectively transform the energy stored in sugars into electricity. Meanwhile, the microbial fuel cells presented in this paper, which could work cleanly at normal temperature with a good cycle property, showed a promising future application in this field.”