“The microbes eat organic material and transfer electrons to an anode buried in the sediment,” said Timothy Ewing, the Ph.D. student who helped put together the microbial fuel cell powering the lights. “The electrons then flow through an external circuit to the cathode up near the surface of the water where they are transferred to oxygen, completing this part of the electricity generating process.”
The microbes are quick eaters, too. Food is at their cell-tips so they can produce electrons easily.
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Low maintenance energy source
Researchers can simulate those continuous conditions in the lab by using river or waste treatment water and replenishing organic materials periodically. For example, systems that Beyenal set up in his lab four years ago using river water and wastewater are still generating energy today.