• A demonstration of bacteria making electricity from light.

    Credit: Courtesy University of Minnesota

    A demonstration of bacteria making electricity from light.

The realms of biology and physics are often treated as distinct fields of inquiry—particularly when it comes to topics such as microbes and magnetism. However, scientists at the University of Minnesota have recently determined that some types of bacteria are able to transform the electrical state of particular metals.

"Our labs focus on the fundamental question of what kinds of bacteria are capable of changing metals from one state to another, and how they do it," said microbiology professor Daniel Bond in a university press release. "Only bacteria can do this—they control the chemistry of soils and water by altering the [electrical] states of most elements."

Bond and his departmental colleague Jeffrey Gralnick have revealed that bacteria steal electrons from—as well as donate electrons to—metals, and in the process generate electrical current. Iron-oxidizing bacteria, for example, remove electrons from iron to form rust. Iron-reducing bacteria, on the other hand, donate electrons to iron to form new magnetic minerals.

Although their research, which has been conducted in partnership with the Office of Naval Research, is still in nascent stages, Bond and Gralnick anticipate the ability to create biosensors that can detect environmental pollutants—including chemical and radioactive waste. "If we can harness the precision of bacterial sensing, I'd love to use bacteria as an early warning system for pollutants," said Bond. "But you can only build these organisms if you understand how they work."

Blaine Brownell, AIA, is a regularly featured columnist whose stories appear on this website each week. His views and conclusions are not necessarily those of ARCHITECT magazine nor of the American Institute of Architects.