“Nanowires” produced by Geobacter in response to an electric field applied to electricity-producing biofilms. These nanowires are composed of cytochrome OmcZ and show 1000-fold higher conductivity and 3-times higher stiffness than the nanowires of cytochrome OmcS important in natural environments, allowing bacteria to transport electrons over 100-times their size. Credit: Sibel Ebru Yalcin. Design: Ella Maru StudioRapid global warming poses a severe and immediate threat to life on Earth.
A potential solution to this vicious circle could be another kind of microbe that eats up to 80% of methane flux from ocean sediments that protect the Earth. How microbes serve as both the biggest producers as well as consumers of methane has remained a mystery because they are very difficult to study in the laboratory.
Using cryo-electron microscopy, Yangqi and the team were able to see the nanowire’s atomic structure and discover that hemes packed closely to move electrons very fast with ultra-high stability. It also explains how these bacteria can survive without oxygen-like membrane-ingestible molecules and form communities that can send electrons over 100 times bacterial size. Yangqi and the team also built nanowires synthetically to explain how bacteria make nanowires on demand.
“We are using these heme wires to generate electricity and to combat climate change by understanding how methane-eating microbes use similar heme wires,” Malvankar said. Reference: “Structure of Geobacter cytochrome OmcZ identifies mechanism of nanowire assembly and conductivity” by Yangqi Gu, Matthew J. Guberman-Pfeffer, Vishok Srikanth, Cong Shen, Fabian Giska, Kallol Gupta, Yuri Londer, Fadel A. Samatey, Victor S. Batista and Nikhil S. Malvankar, 2 February 2023,
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