https://www.newscientist.com/article/dn25894-meet-the-electric-life-forms-that-live-on-pure-energy/
Unlike any other life on Earth, these extraordinary bacteria use energy in its purest form – they eat and breathe electrons – and they are everywhere
By Catherine Brahic
Geobacter – a current favourite
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, 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.
That should not come as a complete surprise, says Kenneth Nealson at the University of Southern California, Los Angeles. We know that life, when you boil it right down, is a flow of electrons: “You eat sugars that have excess electrons, and you breathe in oxygen that willingly takes them.” Our cells break down the sugars, and the electrons flow through them in a complex set of chemical reactions until they are passed on to electron-hungry oxygen.
“Life’s clever. It figures out how to suck electrons out of everything we eat and keep them under control”
In the process, cells make ATP, a molecule that acts as an energy storage unit for almost all living things. Moving electrons around is a key part of making ATP. “Life’s very clever,” says Nealson. “It figures out how to suck electrons out of everything we eat and keep them under control.” In most living things, the body packages the electrons up into molecules that can safely carry them through the cells until they are dumped on to oxygen.
“That’s the way we make all our energy and it’s the same for every organism on this planet,” says Nealson. “Electrons must flow in order for energy to be gained. This is why when someone suffocates another person they are dead within minutes. You have stopped the supply of oxygen, so the electrons can no longer flow.”
[https://www.youtube.com/watch?v=3j_gJ2teK5E]
The discovery of electric bacteria shows that some very basic forms of life can do away with sugary middlemen and handle the energy in its purest form – electrons, harvested from the surface of minerals. “It is truly foreign, you know,” says Nealson. “In a sense, alien.”
Nealson’s team is one of a handful that is now growing these bacteria directly on electrodes, keeping them alive with electricity and nothing else – neither sugars nor any other kind of nutrient. The highly dangerous equivalent in humans, he says, would be for us to power up by shoving our fingers in a DC electrical socket.
To grow these bacteria, the team collects sediment from the seabed, brings it back to the lab, and inserts electrodes into it.
To grow these bacteria, the team collects sediment from the seabed, brings it back to the lab, and inserts electrodes into it.
First they measure the natural voltage across the sediment, before applying a slightly different one. A slightly higher voltage offers an excess of electrons; a slightly lower voltage means the electrode will readily accept electrons from anything willing to pass them off. Bugs in the sediments can either “eat” electrons from the higher voltage, or “breathe” electrons on to the lower-voltage electrode, generating a current. That current is picked up by the researchers as a signal of the type of life they have captured.
“Basically, the idea is to take sediment, stick electrodes inside and then ask ‘OK, who likes this?’,” says Nealson.
Shocking breath
At the Goldschmidt geoscience conference in Sacramento, California, last month, Shiue-lin Li of Nealson’s lab [http://dornsife.usc.edu/labs/nealsonlab/members/] presented results of experiments growing electricity breathers in sediment collected from Santa Catalina harbour in California. Yamini Jangir, also from the University of Southern California, presented separate experiments which grew electricity breathers collected from a well in Death Valley in the Mojave Desert in California.
Over at the University of Minnesota in St Paul, Daniel Bond and his colleagues have published experiments showing that they could grow a type of bacteria that harvested electrons from an iron electrode (mBio, doi.org/tqg). That research, says Jangir’s supervisor Moh El-Naggar, may be the most convincing example we have so far of electricity eaters grown on a supply of electrons with no added food.
But Nealson says there is much more to come. His PhD student Annette Rowe has identified up to eight different kinds of bacteria that consume electricity. Those results are being submitted for publication.
Nealson is particularly excited that Rowe has found so many types of electric bacteria, all very different to one another, and none of them anything like Shewanella or Geobacter. “This is huge. What it means is that there’s a whole part of the microbial world that we don’t know about.”
“This is huge. What it means is there’s a whole part of the microbial world that we don’t know about”
Discovering this hidden biosphere is precisely why Jangir and El-Naggar want to cultivate electric bacteria. “We’re using electrodes to mimic their interactions,” says El-Naggar. “Culturing the ‘unculturables’, if you will.” The researchers plan to install a battery inside a gold mine in South Dakota to see what they can find living down there.
NASA is also interested in things that live deep underground because such organisms often survive on very little energy and they may suggest modes of life in other parts of the solar system.
Electric bacteria could have practical uses here on Earth, however, such as creating biomachines that do useful things like clean up sewage or contaminated groundwater while drawing their own power from their surroundings. Nealson calls them self-powered useful devices, or SPUDs.
Practicality aside, another exciting prospect is to use electric bacteria to probe fundamental questions about life, such as what is the bare minimum of energy needed to maintain life.
For that we need the next stage of experiments, says Yuri Gorby, a microbiologist at the Rensselaer Polytechnic Institute in Troy, New York: bacteria should be grown not on a single electrode but between two. These bacteria would effectively eat electrons from one electrode, use them as a source of energy, and discard them on to the other electrode.
Gorby believes bacterial cells that both eat and breathe electrons will soon be discovered. “An electric bacterium grown between two electrodes could maintain itself virtually forever,” says Gorby. “If nothing is going to eat it or destroy it then, theoretically, we should be able to maintain that organism indefinitely.”
It may also be possible to vary the voltage applied to the electrodes, putting the energetic squeeze on cells to the point at which they are just doing the absolute minimum to stay alive. In this state, the cells may not be able to reproduce or grow, but they would still be able to run repairs on cell machinery. “For them, the work that energy does would be maintaining life – maintaining viability,” says Gorby.
How much juice do you need to keep a living electric bacterium going? Answer that question, and you’ve answered one of the most fundamental existential questions there is.
Leader: “Spark of life revisited thanks to electric bacteria” [https://www.newscientist.com/article/mg22329781-600-spark-of-life-revisited-thanks-to-electric-bacteria]
Wire in the mud
Electric bacteria come in all shapes and sizes. A few years ago, biologists discovered that some produce hair-like filaments that act as wires, ferrying electrons back and forth between the cells and their wider environment. [https://www.newscientist.com/article/mg21428712-300-giant-living-power-cables-let-bacteria-respire] They dubbed them microbial nanowires.
Lars Peter Nielsen and his colleagues at Aarhus University in Denmark have found that tens of thousands of electric bacteria can join together to form daisy chains that carry electrons over several centimetres – a huge distance for a bacterium only 3 or 4 micrometres long. It means that bacteria living in, say, seabed mud where no oxygen penetrates, can access oxygen dissolved in the seawater simply by holding hands with their friends.
Such bacteria are showing up everywhere we look, says Nielsen. One way to find out if you’re in the presence of these electron munchers is to put clumps of dirt in a shallow dish full of water, and gently swirl it. The dirt should fall apart. If it doesn’t, it’s likely that cables made of bacteria are holding it together.
Nielsen can spot the glimmer of the cables when he pulls soil apart and holds it up to sunlight (see video).
Flexible biocables
It’s more than just a bit of fun. Early work shows that such cables conduct electricity about as well as the wires that connect your toaster to the mains. That could open up interesting research avenues involving flexible, lab-grown biocables.
(This article appeared in print under the headline “The electricity eaters”)
-----EOL
How can people hear something like this a be athiest boggles the mind
>>143373
How can people hear something like this a warp it into an indictment of a group of people boggles the mind
https://www.nsf.gov/discoveries/disc_summ.jsp?cntn_id=112597
Batteries Made of Bacteria?
Researchers believe the energy produced by Geobacter microbes can be harnessed for electrical power, environmental remediation and biosensors
[https://www.nsf.gov/discoveries/disc_images.jsp?cntn_id=112597&org=NSF] Daniel Bond holds a jar of Geobacter microbes.
November 19, 2008
Researchers at the University of Minnesota-Twin Cities are studying a remarkable species of bacteria, Geobacter sulfurreducens, that produces electric current when attached to a graphite electrode or other conductive surface.
Geobacter's current capability already has been harnessed in so-called "microbial fuel cells" that use bacteria to convert wastewater organic compounds into electricity. Daniel Bond, a microbiologist at the University of Minnesota-Twin Cities, and his team have demonstrated the same phenomenon can be harnessed for use in batteries and biosensors.
A traditional battery or a hydrogen fuel cell requires a precious-metal catalyst such as platinum to strip electrons off the fuel source and pull them onto the electrode to generate electricity. Geobacter requires only graphite, an inexpensive and widely available form of carbon, to accomplish the same feat.
"Other species of bacteria may produce just as many electrons as they oxidize available fuels, but their cell membranes act like an insulator for electron transport," said Daniel Bond, a microbiologist at the University of Minnesota-Twin Cities. "With Geobacter, it's the difference between a rickety one-lane bridge and a modern 12-lane highway. The electrons pass easily through internal membranes and cell walls and hop onto the electrode." Each "hop" requires them to travel about 10 Angstroms.
Geobacter has proteins that guide electrons all the way to the electrode. "This makes Geobacter unique in comparison to other bacteria," Bond said. "Because of the distances involved, we know that multiple proteins are involved, which adds to the complexity and why we can't just clone a gene into E. coli to do this."
The National Science Foundation (NSF) provided funding for the study.
Geobacter was discovered in the late 1980s by geochemist Derrick Lovely, who demonstrated that a lot of metal chemistry happening in underground aquifers and sediments might be due to bacteria, not just abiotic chemical reactions. As a result, he isolated Geobacter and scientists around the world began studying its properties.
The similarities between microbes and batteries have been evident to scientists for many years and the idea of using the former to serve as the latter has been around for at least 100 years. The problem was that known species of bacteria didn't make a particularly good battery. Recently, when members of the U.S. Naval Research Laboratory found that electrodes in ocean sediments could generate electricity, the possible involvement of bacteria was more obvious. This led to the discovery that metal-reducing bacteria could catalyze this process all by themselves.
There are uses for remote power sources deep in the ocean for sensors and communications and what a Geobacter battery lacks in power, it makes up in simplicity and efficiency. "There are no moving parts, it just works," Bond said. Other research groups had made some progress in characterizing Geobacter's current generating properties.
"These bacteria exist to oxidize metal and pass electrons to whatever will take them," he said. "With the graphite electrodes, we fool the Geobacter into thinking they have an unlimited supply of metal; instead of a few bites, they get an all-you-can-eat buffet." The bacteria eat and grow and eat and grow but instead of getting fat like we do, they make additional copies of themselves. "The surface area of the electrode is limiting at some point. We don't really know how many bacteria we can pack on."
Another application for this mighty microbe is in waste-water treatment plants. The current technology requires a lot of oxygen, which gets expensive to pump in. Geobacter could help purify the water and simultaneously produce enough electricity to help pay the power bill.
Bond's group will continue to explore ways to improve Geobacter's usefulness in energy, sensors and environmental cleanup, but they also want to understand better just how the bug does what it does.
"Part of our lab is working to scale-up the technology, but most of the work focuses on 'how' and 'why,'" Bond said.
When it comes to the inner workings of a bacterial cell, scientists have 100 years of knowledge to build on. But research on how the cells get electrons to the surface is only about 10-20 years old.
"We're lucky Geobacter's outer surface has an affinity for graphite. We're working on making a better 'lock-and-key' connection," Bond said. "Right now it just sort of fits."
-- Diane Banegas, National Science Foundation (703) 966-0316 [email protected]
Investigators
Daniel Bond
William Smyrl
Related Institutions/Organizations
University of Minnesota-Twin Cities
Locations
Minnesota
Related Awards
#0454861 Miniaturization of Mediatorless Microbial Fuel Cells for High-Throughput Studies of Bacteria-Electrode Interactions [https://www.nsf.gov/awardsearch/showAward.do?AwardNumber=0454861]
Total Grants
$449,389
-----EOL
>>143384
I used to work near Dr. Bond. He was a cool guy and his work is pretty amazing.
If you are interested in reading about another organism look into Jeff Gralnick's lab. He is another researcher at the University of Minnesota Twin Cities is doing similar work with Shewanella which has similar properties to geobacter.
This is the first thing I heard this year that made me look forward to the future. What if you could power a water desalination machine with these things, feeding them with the electrons from the salt?
Is it just me, or did that popular science writer just pull the term "electric bacteria" out of their ass?
>>143460
Probably, since there were only two species known to do it up until just recently. What would you call them? Electrophage might work.
alot of proteins in electrons
>>143470
>proteins in electrons
What did he mean by this?
>>143464
Phage is a bacterial virus, not a bacteria.
>>143484
True. Phage means "to devour", but there's probably a better term I'm not aware of.
>>143446
This is a good idea anon! Desalination is the future and figuring out the most efficient way of producing potable water should be humanity's number one priority.
>>143504
Decreasing population growth should be mankind's number one priority.
>>143517
Someone else fucking gets it! It would be tough to implement, though. And a need based economy rather than market based.
>>143517
you're disgusting
How the fuck are we supposed to care for the elderly without an increasing population?
Can these bacteria power nurse robots?
>>143532
It doesn't take one person for every elderly person for people to get proper care. There are more problems with an increasing population than a declining one.
>>143532
easy, automation. soon enough we will all be like humans from Wall-E, automation does and tells us everything.
>>143517
decreasing population is one way to maintain control at its most efficient. but it would not be "humanly-fair".. i would see it better to control population rate like how China did it.
>>143373
Ebola, tuberculosis, plague, polio, measles, meningitis, rabies, etc
>>143636
>But those diseases are only meant for those unworthy of God's grace.
They'll rationalize everything.
>>143546
By creating a frenzy of abortions and drowned children?
>>143373
You give the religious a bad name. The promotion of wilful ignorance and blind faith will always be weapons for the non-believer. Just apply your logic to everything else, since god made everything else...
>New discovery! Shit comes from digested food!
>how can people hear this an' be athiest, boggles the mind
>Pastor fondles boy
>how can people hear this an' be athiest, boggleys the mind
>Human Scientist cures diabetes, a disease divinely created by god
>how can people hear this an' be athiest, boggles the mind!?
>>143537
>It doesn't take one person for every elderly person for people to get proper care.
No shit. This is relevant how?
>>143537
>There are more problems with an increasing population than a declining one.
No there aren't. This is fuckin stupid and illogical.
>>143546
So nurse robots. Let me know when sonebody invents actual robots. Automation is not comparable to a robot making sone handicap breakfast and giving insulin shots.
This kind of technology is a dream. We still need more humans.