Mud-Loving Bacteria Increases Fuel Cell Output by 800%

Mud-Loving Bacteria Increases Fuel Cell Output by 800%

Written by Jerry James Stone

Published on September 1st, 20094 CommentsPosted in Fuel Cells

Researchers from the University of Massachusetts Amherst evolved a new strain of the Geobacter microbe that increases power output per cell by 800%.

The hairy mud-loving microbe uses its hairlike filaments–called pili–to produce an electric current from both mud and waste water. The pili are only 5 nanometers in diameter (20,000 times smaller than a human hair); they’re also a thousand times longer than they are wide. But they are strong!

“This new study shows that output can be boosted and it gives us good insights into what it will take to genetically select a higher-power organism.” The work, supported by the Office of Naval Research and the U.S. Department of Energy, is described in the August issue of the journal, Biosensors and Bioelectronics.

The pili–usually called nanowires–have an amazing ability to shift electrons. Which is exactly how they create a current from waste and mud.

Creating a unique biofilm, they transfer the electron products to iron in both soil and waste. It’s the same process that allows bacteria to stick to your teeth but requires less flossing.



“In very short order we increased the power output by eight-fold, as a conservative estimate,” says Derek Lovley from the research team. “With this, we’ve broken through the plateau in power production that’s been holding us back in recent years.”

These findings open many doors for microbial fuel cell architecture and will hopefully lead to many applications beyond extracting electricity from crap.

One possibility is treating a single home’s waste in order to produce localized power for the unit. Of course, I rather see that process implemented on a grand scale like for businesses. But it is more likely to take root developing countries.

And for you Apple geeks there might even be a crap-powered iPhone in your future.

The researchers grew the bacteria on graphite electrodes using acetate as a food for the colony. Once the slimy biofilm was formed they added a small 400-millivolt current that forced the Geobacter to lose more electrons.

Lovely and his colleagues first discovered the Geobacter back in 1987 in sediment under the Potomac River. Initially it was used in decontaminating soil as it respires iron and other metals similarly to the way we breathe. It was in 2002 when they discovered it could produce electricity from organic matter and all hell broke loose. But it wasn’t til 2005 that the electrically conductive pili were discovered.

A genus of proteobacteria, Geobacter are an anaerobic respiration bacterial species. It was the first organism with the ability to oxidize radioactive metals and petroleum compounds into environmentally benign carbon dioxide