Electric Bacteria Create Currents Out of Thin - and Thick - Air
NPC-131072 writes:
From Sciencemag
Generating electricity from thin air may sound like science fiction, but a new technology based on nanowire-sprouting bacteria does just that-as long as there's moisture in the air. A new study shows that when fashioned into a film, these wires-protein filaments that ferry electrons away from the bacteria-can produce enough power to light a light-emitting diode. The film works by simply absorbing humidity from the surrounding air. Though researchers aren't sure exactly how these wires work, the tiny power plants pack a punch: Seventeen devices linked together can generate 10 volts, which is enough electricity to power a cellphone.
The new method should be considered a "milestone advance" says Guo Wanlin, a materials scientist at Nanjing University of Aeronautics and Astronautics who wasn't involved with the work. Guo studies hydrovoltaics, a molecular approach to harvesting electricity from water.
[...] They [...] exposed their device to different levels of humidity. It worked best in air of about 45% humidity, but also in conditions as dry as the Sahara Desert or as humid as New Orleans, the team reports today in Nature. The secret, they say, is that with just the upper side of the film absorbing moisture, a moisture gradient develops, with droplets constantly diffusing in and out of the top. The droplets can dissociate into hydrogen and oxygen ions, causing charges to build up near the top. The difference in charge between the top and bottom of the film causes electrons to flow, Yao explains.
[...] [University of Massachusetts, Amherst microbiologist Derek] Lovley has proposed a way to do that. Growing Geobacter to harvest nanowires is difficult, so Lovley has genetically engineered the easy-to-grow bacterium Escherichia coli to produce nanowires. The E. coli created nanowires of the same diameter and with the same conducting power as Geobacter's, he and his colleagues reported in a November 2019 preprint posted to bioRxiv.
[Note: Yes, the linked article does say that "10 volts, which is enough electricity to power a cell phone." --Ed.]
Journal Reference:
Toshiyuki Ueki, David J.F. Walker, Trevor L. Woodard, Kelly P. Nevin, Stephen S. Nonnenmann, Derek R. Lovley. "An Escherichia coli Chassis for Production of Electrically Conductive Protein Nanowires", bioRxiv (DOI: 10.1101/856302)
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