Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

UMass Amherst Researchers Reveal Mechanism of Novel Biological Electron Transfer

20.03.2013
When researchers at the University of Massachusetts Amherst led by microbiologist Derek Lovley discovered that the bacterium Geobacter sulfurreducens conducts electricity very effectively along metallic-like “microbial nanowires,” they found physicists quite comfortable with the idea of such a novel biological electron transfer mechanism, but not biologists.
“For biologists, Geobacter’s behavior represents a paradigm shift. It goes against all that we are taught about biological electron transfer, which usually involves electrons hopping from one molecule to another,” Lovley says. “So it wasn’t enough for us to demonstrate that the microbial nanowires are conductive and to show with physics the conduction mechanism, we had to determine the impact of this conductivity on the biology.”

“We have now identified key components that make these hair-like pili we call nanowires conductive and have demonstrated their importance in the biological electron transport. This time we relied more on genetics. I think most biologists are more comfortable with genetics rather than physics,” Lovley adds.

“From my perspective, this is huge. It really clinches a big question. We overturned the major objection the biologists were making and confirmed the assumption in our earlier work, that real metallic-like conductivity is taking place.”

Findings are described in an early online issue of mBio, the open-access journal of the American Society for Microbiology. In addition to Lovley, the UMass Amherst team includes first author Madeline Vargas, with Nikhil Malvankar, Pier-Luc Tremblay, Ching Leang, Jessica Smith, Pranav Patel, Oona Snoeyenbos-West and Kelly Nevin.

In 2011, Lovely’s group discovered a fundamental, previously unknown property of pili in Geobacter. They found that electrons are transported along the pili via the same metallic-like conductivity found in synthetic organic materials used in electronics. Electrons are conducted over remarkable distances, thousands of times the cell’s length. But exactly how the pili accomplished this wasn’t clear.

They knew that the conductivity of synthetic conducting organic materials can be attributed to aromatic ringed structures which share electrons, suspended in a kind of a cloud that allows the overlapping electrons to easily flow. It seemed possible that amino acids, which have similar aromatic rings, might serve the same function in biological protein structures like pili. Lovley’s team looked for likely aromatic amino acid targets and then substituted non-aromatic amino acids for the aromatic ones to see if this reduced the conductivity of the pili.

It worked. The re-engineered pili with non-aromatic compounds substituted for aromatic ones looked perfect and unchanged under a microscope, but now they no longer functioned as wires. “This new strain is really bad at what Geobacter does best,” Lovley says. “Geobacter is known for its ability to grow on iron minerals and for generating electric current in microbial fuel cells, but without conductive pili those capabilities are greatly diminished.”

“What we did is equivalent to pulling the copper out of an extension cord,” he adds. “The cord looks the same, but it can’t conduct electricity anymore.”

The ability of protein filaments to conduct electrons in this way not only has ramifications for scientists’ basic understanding of natural microbial processes but practical implications for environmental cleanup and the development of renewable energy sources as well, he adds. Lovley’s UMass Amherst lab has already been working with federal agencies and industry to use Geobacter to clean up groundwater contaminated with radioactive metals or petroleum and to power electronic monitoring devices with current generated by Geobacter.

His group has also recently shown that Geobacter uses its nanowires to feed electrons to other microorganisms that can produce methane gas. This is an important step in the conversion of organic wastes to methane, which can then be burned to produce electricity.

As more states, including national leader Massachusetts, pass laws to prevent hospitals, universities, hotels and large restaurants from disposing of food waste in landfills, Geobacter’s role in producing methane could be part of the solution for how to deal with this waste. The Massachusetts law goes into effect in 2014. “Waste to methane is a well developed green energy strategy in Europe and is almost certain to become more important here in Massachusetts in the near future,” Lovley notes.

Funding for this work was from the U.S. Office of Naval Research and the Department of Energy.

Janet Lathrop | EurekAlert!
Further information:
http://www.umass.edu

More articles from Power and Electrical Engineering:

nachricht How protons move through a fuel cell
22.06.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt

nachricht Fraunhofer IZFP acquires lucrative EU project for increasing nuclear power plant safety
21.06.2017 | Fraunhofer-Institut für Zerstörungsfreie Prüfverfahren IZFP

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Study shines light on brain cells that coordinate movement

26.06.2017 | Life Sciences

Smooth propagation of spin waves using gold

26.06.2017 | Physics and Astronomy

Switchable DNA mini-machines store information

26.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>