Breakthrough in race to create 'bio-batteries'

March 25, 2013
Shewanella oneidensis bacteria. Credit: Alice Dohnalkova.

(Phys.org) —Scientists at the University of East Anglia have made an important breakthrough in the quest to generate clean electricity from bacteria.

Findings published today in the journal Proceedings of the National Academy of Sciences (PNAS) show that proteins on the surface of can produce an electric current by simply touching a .

The research shows that it is possible for bacteria to lie directly on the surface of a metal or mineral and transfer electrical charge through their cell membranes. This means that it is possible to 'tether' bacteria directly to electrodes – bringing scientists a step closer to creating efficient or 'bio-batteries'.

The team collaborated with researchers at Pacific Northwest National Laboratory in Washington State in the US. The project was funded by the Biotechnology and Biological Sciences Research Council (BBSRC) and the US Department of Energy.

(pictured) is part of a family of . The research team created a of this bacteria using just the proteins thought to shuttle the electrons from the inside of the microbe to the rock.

They inserted these proteins into the lipid layers of vesicles, which are small capsules of such as the ones that make up a bacterial membrane. Then they tested how well electrons travelled between an on the inside and an iron-bearing mineral on the outside.

Lead researcher Dr Tom Clarke from UEA's school of Biological Sciences said: "We knew that bacteria can transfer electricity into metals and minerals, and that the interaction depends on special proteins on the surface of the bacteria. But it was not been clear whether these proteins do this directly or indirectly though an unknown mediator in the environment.

"Our research shows that these proteins can directly 'touch' the mineral surface and produce an electric current, meaning that is possible for the bacteria to lie on the surface of a metal or mineral and conduct electricity through their cell membranes.

"This is the first time that we have been able to actually look at how the components of a bacterial cell membrane are able to interact with different substances, and understand how differences in metal and mineral interactions can occur on the surface of a cell.

"These bacteria show great potential as microbial fuel cells, where electricity can be generated from the breakdown of domestic or agricultural waste products.

"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."

Biochemist Liang Shi of Pacific Northwest National Laboratory said: "We developed a unique system so we could mimic electron transfer like it happens in cells. The electron transfer rate we measured was unbelievably fast - it was fast enough to support bacterial respiration."

The finding is also important for understanding how carbon works its way through the atmosphere, land and oceans.

"When organic matter is involved in reducing iron, it releases carbon dioxide and water. And when iron is used as an energy source, bacteria incorporate carbon dioxide into food. If we understand , we can learn how bacteria controls the carbon cycle," said Shi.

Explore further: Progress Toward a Biological Fuel Cell?

More information: 'Rapid electron exchange between surface-exposed bacterial cytochromes and Fe(III) minerals' by Thomas A Clarke, Gaye White, Julea N Butt, and David J Richardson (all UEA, UK), and Zhri Shi, Liang Shi, Zheming Wang, Alice C Dohnalkova, Matthew J Marshall, James K Fredrickson and John M Zachara (all PNNL, USA) is published by PNAS on Monday, March 25. (Will be available at www.pnas.org/lookup/doi/10.1073/pnas.1220074110 )

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Martin_Shaw
1.5 / 5 (8) Mar 25, 2013
Brought to you by UEA who pride themselves on hiding the details of their research from the scientific community. Friends of Al Gore and the armchair scientist crowd. Bacterial energy all makes sense as long as you disregard the energy you have to input to keep bacteria alive.
rfw
5 / 5 (1) Mar 25, 2013
One also needs to deal with the metabolic byproducts that bacteria create when considering the total energetic economics of this kind of idea. Great idea and what is the implications of the big picture for how it functions and the consequences of using it?
Moebius
1 / 5 (1) Mar 26, 2013
Said the E Coli to the Colliform, "Wake up, coppertop."
AWaB
1 / 5 (2) Mar 26, 2013
I couldn't agree more with Martin. I thought this would be an excellent article when I saw the headline. Then I read where the 'discovery' was made. Anything coming from that place is suspect! It should be the same for any institution that is caught allowing its researchers to manipulate and falsify data.

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