University of East Anglia researchers are now a step closer towards harnessing bacteria for clean energy, releasing a report that details electron action responsible for conducting electricity.

Published in the Journal of the Royal Society Interface, the report showed that electrons can hop across insulated areas in bacterial proteins and that the electrical transfer rate depends on where and how close together the electron's "stepping stones" are. Researchers are hoping the natural process can be harnessed, allowing for improvements in bio batteries that derive power from animal or human waste and can be used to produce energy for portable devices like laptops, tablets, and smartphones.

A lot of microorganisms can survive even without oxygen, turning to "rocks" like iron minerals to breathe instead. These microorganisms also derive energy from fuel molecules combusting within cells producing a side product, an electrical flow that is possible to direct across the outer membrane of the bacteria and delivered to breathing rocks in their natural environment. To harness this electrical flow, it may also be taken to graphite electrodes installed in fuel cells. This kind of reaction means that bacteria is able to release electrical charge from within a cell and into a mineral, similar to how a neutral wire works in a household plug.

For the study, researchers looked into proteins known as multi-haem cytochromes. These proteins are found in bacteria that use rocks to breathe called Shewanella.

"This research shows that these centres should be considered as discs that the electrons hop across," explains Prof. Julea Butt from UEA's School of Biological Sciences and School of Chemistry, the study's lead researcher.

Butt adds that the results of their findings are exciting advancements in how bacterial species can move electrons is understood. By keenly observing how electrons are transferred from inside to outside of a cell, researchers will be able to understand bacterial behavior better in terms of dynamic modules for electron transfer.

Researchers are also hopeful that the information they get from understanding the inner workings of this natural process will be used to inspire designs for bespoke proteins. These proteins may then be used as microbial fuel cells for the clean and sustainable production of energy.

Receiving funding support from the Biotechnology and Biological Sciences Research Council, the study was carried out with help from researchers from the Pacific Northwest National Laboratory and the University College London. Other authors include: Jochen Blumberger, Kevin M. Rosso, and Marian Breuer.

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