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AnonTechie writes:

Stick an electrode in the ground, pump electrons down it, and they will come: living cells that eat electricity. We have known bacteria to survive on a variety of energy sources, but none as weird as this. Think of Frankenstein's monster, brought to life by galvanic energy, except these "electric bacteria" are very real and are popping up all over the place.

Unlike any other living thing on Earth, electric bacteria use energy in its purest form -- naked electricity in the shape of electrons harvested from rocks and metals. We already knew about two types [ed: subscription required], Shewanella and Geobacter. Now, biologists are showing that they can entice many more out of rocks and marine mud by tempting them with a bit of electrical juice. Experiments growing bacteria on battery electrodes demonstrate that these novel, mind-boggling forms of life are essentially eating and excreting electricity.

JNCF writes:

The bacteria Geobacter naturally forms nanowires 30,000 times smaller than a human hair, but genetic modification sponsored by the Office of Naval Research (ONR) has made them 2,000 times more electrically conductive than they previously were.

The headline is stolen from a paywalled journal article. What other uses for these brave new bio-wires can you think of, Soylentils?

Original Submission

takyon writes:

Wired Bacteria Form Nature's Power Grid: 'We Have an Electric Planet'

Electroactive bacteria were unknown to science until a couple of decades ago. But now that scientists know what to look for, they're finding this natural electricity across much of the world, even on the ocean floor. It alters entire ecosystems, and may help control the chemistry of the Earth. "Not to sound too crazy, but we have an electric planet," said John Stolz, a microbiologist at Duquesne University in Pittsburgh.

In the mid-1980s, Dr. Stolz was helping to study a baffling microbe fished out of the Potomac River by his colleague Derek Lovley. The microbe, Geobacter metallireducens, had a bizarre metabolism. "It took me six months to figure out how to grow it in the lab," said Dr. Lovley, now a microbiologist at the University of Massachusetts at Amherst.

[...] In the early 2000s, a Danish microbiologist named Lars Peter Nielsen discovered a very different way to build a microbial wire. He dug up some mud from the Bay of Aarhus and brought it to his lab. Putting probes in the mud, he observed the chemical reactions carried out by its microbes.

[...] Each wire runs vertically up through the mud, measuring up to two inches in length. And each one is made up of thousands of cells stacked on top of each other like a tower of coins. The cells build a protein sleeve around themselves that conducts electricity.

As the bacteria at the bottom break down hydrogen sulfide, they release electrons, which flow upward along the "cable bacteria" to the surface. There, other bacteria — the same kind as on the bottom, but employing a different metabolic reaction — use the electrons to combine oxygen and hydrogen and make water.

Cable bacteria are not unique to Aarhus, it turns out. Dr. Nielsen and other researchers have found them — at least six species [open, DOI: 10.1016/j.syapm.2016.05.006] [DX] so far — in many places around the world, including tidal pools, mud flats, fjords, salt marshes, mangroves and sea grass beds.

Original Submission

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)

Original Submission