When you think of bacteria, the last word that might come to mind is “clean.” However, researchers at the University of East Anglia have made a breakthrough in battery technology that will allow microbes to generate clean electricity. Their work was published this week in the journal Proceedings of the National Academy of Sciences (PNAS), and it shows that the surface of the organisms can produce an electric current when touching a mineral surface. When lying directly on a mineral or metal surface, the bacteria can be “tethered” to electrodes, bringing the scientists one step closer to developing a battery powered by living creatures.
The team at the University of East Anglia collaborated with researchers from the Pacific Northwest National Laboratory in Washington to create a synthetic version of the marine bacteria, Shewanella oneidensis. They did this by using the proteins used to move electrons from the inside of the cell body to the rock. Inserting these proteins into lipid layers of the actual bacteria’s membranes, they then tested how well the electrons moved between the inside of the donor to the mineral surface on which it was resting. For the first time, the scientists were able to observe how the bacteria could directly conduct electricity between the metal and the surface of its body. The electron transfer rate was extremely fast, enough to support respiration. Their observations are critical to the eventual fabrication of living batteries.
“These bacteria show great potential as microbial fuel cells, where electricity can be generated from the breakdown of domestic or agricultural waste products,” said lead researcher, Dr Tom Clarke from UEA’s school of Biological Sciences. “Another possibility is to use these bacteria as miniature factories on the surface of an electrode, where chemicals reactions take place inside the cell using electrical power supplied by the electrode through these proteins.”
The findings are also important to understanding how carbon moves its way through the atmosphere, land, and oceans. When organic matter is involved in reducing iron, it releases CO2 and water. If iron is used as an energy source, bacteria use the CO2 as food. By investigating electron transfer, the researchers may also shed some light on how the microbes are involved in the carbon cycle.
Via Science Daily