Geobacter is quite the interesting genus of bacteria. As extremophiles, they can live quite happily under conditions too toxic for most creatures big or small. Moreover, many Geobacter microbes are able to convert those toxins into materials far less dangerous -- a process referred to as "bioremediation" -- sometimes generating electricity in the process.

But in trying to better understand how Geobacter is able to do all of this, researchers at the University of Massachusetts at Amherst -- including the original discoverer of the Geobacter line -- stumbled across another remarkable characteristic of these creatures: nanowires. Geobacter is criss-crossed with tiny (3-5 nanometer wide) protein wires able to conduct electrons out of the cell.

The remarkable and unexpected discovery of microbial structures comprising microbial nanowires that may enable a microbial community in a contaminated waste site to form mini-power grids could provide new approaches to using microbes to assist in the remediation of DOE waste sites; to support the operation of mini-environmental sensors, and to nano-manufacture in novel biological ways. This discovery also illustrates the continuing relevance of the physical sciences to today’s biological investigations." [...]

Ultrafine wires, often referred to as nanowires, are required for further miniaturization of electronic devices. Manufacturing nanowires from more traditional materials such as metals, silica, or carbon is difficult and expensive. However, it is easy to grow billions of Geobacter cells in the laboratory and harvest the microbial nanowires that they produce. Furthermore, by altering the DNA sequence of the genes that encode for microbial nanowires, it may be possible to produce nanowires with different properties and functions.

Another interesting implication of this research is that it suggests a mechanism for microbes to share energy in a mini-power grid. The nanowire pili of individual Geobacter often intertwine, suggesting a strategy by which Geobacter might share electricity.

The article appears in the current Nature, and is available for download (PDF) from the Geobacter Project website.

The future will be built with the guts of creatures far too small to see.

Wow. Like, really, wow.

[Look at me doing my part to keep the comments section of WorldChanging an industry leader in articulate, intelligent exploration of the world's most pressing issues and the solutions we're developing to address them.]

Posted by: Alex Steffen on June 30, 2005 7:47 PM

Yup, Geobacter is really really cool from a scientific standpoint, and I believe we're going to see a whole lot more advances in cell biology and metabolic engineering because of them.

However, translating this academic goodness into an actual real-world benefit is more tricky. Two little-known facts to enforce the coolness of Geobacter; first, it can also reduce uranium, precipitating it out of groundwater. Second, the easiest way to grow up big concentrations of geobacter is . . . add iron sulfate to an anaerobic environment and wait. It is probably the easiest and most useful bug we've got for doing bioremediation, but it is not being used.

This is because of the central bioremediation tragedy: bugs can eat anything, they will live in harsh conditions with no help, just to break down threatening chemicals, because that is what they eat. Though they will do this much more slowly, this allows the powers-that-be to say "The Problem is Being Solved, Folks. Just Have To Give it Time". And we get to stick with contaminated groundwater for the next couple hundred years.

Posted by: Ben Hunt on July 1, 2005 7:27 AM