Researchers have found a way of converting sugars into electricity with an efficiency that makes the technique suitable for use in cell phones. Professor Derek Lovley and postdoctoral researcher Swades Chaudhuri, both based at the University of Massachusetts Amherst, have discovered a microorganism that is capable of stable, long-term electricity production by oxidizing carbohydrates. The organism, Rhodoferax ferrireducens, transfers electrons directly onto an electrode as it metabolizes sugar into electricity, producing carbon dioxide as a byproduct.
"There's been a lot of interest in microbial fuel cells trying to covert sugar into electricity," Lovley said. "But in the past, they've converted 10 percent or less of the available electrons, and we're up over 80 percent. And previous attempts to convert carbohydrates to electricity have required an electron shuttle, or mediator, which is typically toxic to humans."
The organism was isolated in Lovley's microbiology lab at the University of Massachusetts Amherst from aquifer sediments in Virginia during a U.S. Department of Energy study.
In theory, this method would allow a cup of sugar to power a 60-watt light bulb for 17 hours, but Lovley said the device needs improvement before it can be used commercially.
"There are still issues with getting a high enough voltage and converting the sugar to electricity fast enough," he said. "Although the process is highly efficient, it is slow. And as the process is right now, we're not talking about a lot of power. It's barely enough to run a calculator, but we did it using unpolished graphite as a receptor. There are almost certainly better electroactive materials.
"I don't want to give the impression that it's 'Back to the Future,' where we stuff a banana in the engine and go, but it's a pretty good leap from where microbial fuel cells were before."
Chaudhuri's and Lovley's findings will appear in the October issue of Nature Biotechnology."
Posted to the site on 9th September 2003
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