Bacteria could power tiny robots

Microbe that releases electrons as a waste product someday could fit in a fuel cell.

A strain of bacteria that releases electrons as a waste product could become the secret ingredient for developing fuel cells for spy drones and other small robots.

Researchers at Rice University and the University of Southern California have embarked on a project to harness the power of Shewanella oneidensis, a microorganism that essentially spits lightning. Rather than consume oxygen to turn food into energy, Shewanella consumes metals.

The waste product of its metabolic process comes in the form of excess electrons stripped from the metals but not recombined in subsequent chemical reactions. The bacteria lives in soil, water and other environments and can extract its necessary nutrients from a variety of materials.

In a fuel cell, the idea is that colonies of Shewanella will attach themselves to the anode, a component inside fuel cells and batteries that gathers electrons, and produce electrons.

"You can feed them pretty much what is available," said Andreas Luttge, an associate professor of earth sciences and chemistry at Rice. "The goal would be to feed them waste water and produce energy."

Hybrid fuel cells--where one strain of bacteria feeds off the waste product of another to produce electricity--are also possible.

Microbes could become one of the crucial ingredients in the future of the energy industry. Researchers at Stanford University have isolated a microbe that turns light into hydrogen, which could become a fuel source. Meanwhile, Craig Venter, the first person to map the human genome, has formed a company that will try to develop energy-producing microbes.

While the concept is feasible, researchers now have to figure out how to optimize the processes involved in creating a fuel cell. Kenneth Nealson, the USC Wrigley chair in environmental studies and professor of earth sciences and biological sciences, will head up the research on altering the genetic pathways of Shewanella for maximum electron production. Nealson is one of the pioneers of geobiology and has conducted extensive research on how microbes survive in oxygen poor environments.

Luttge and others at Rice will experiment with the anode to improve bacterial attachment and other parameters.

In the next five years, the team wants to develop a fuel cell that can propel itself.

The research is funded by $4.4 million from the Department of Defense's Multidisciplinary University Research Initiative. The Defense Department is determined to put more robots in the field to transport equipment, conduct battle operations, or serve as reconnaissance vehicles. Conceivably, a small robot powered by a bacteria fuel cell could shuttle a camera or listening device unobtrusively next to someone.

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