Cyborg bacteria in the news

August 30, 2017 10:56 AM

'Cyborg' bacteria deliver green fuel source from sunlight. Scientists have created bacteria covered in tiny semiconductors that generate a potential fuel source from sunlight, carbon dioxide and water. These newly boosted bacteria produce acetic acid, essentially vinegar, from CO2, water and light. They have an efficiency of around 80%, which is four times the level of commercial solar panels, and more than six times the level of chlorophyll. We prize these cyborg bacteria and their ability to make acetate because they produce a substrate that we can already use to produce more valuable and more interesting products," said Dr Sakimoto.
posted by aleph (25 comments total)

So we're only "self-reproducing" away from grey goo then? They've solved the "outcompete nature" part?
posted by cschneid at 11:05 AM on August 30, 2017

They've solved the "outcompete nature" part?

It sounds like these are completely ordinary bacteria, but fed a little bit of cadmium. So they can't outcompete bacteria in the wild.
posted by BungaDunga at 11:10 AM on August 30, 2017 [1 favorite]

They'll be back.
posted by It's Raining Florence Henderson at 11:18 AM on August 30, 2017 [1 favorite]

For anyone wondering how the acetic acid these guys produce is useful as a fuel source:

"We have collaborators who have a number of strands of E. coli that are genetically engineered to take acetic acid as their food source and they can upgrade it into butanol and a polymer called polyhydroxybutyrate."

So, that's a pretty neat little production chain!

One of the researchers, Dr. Yang, also mentions that they're experimenting with "more benign" alternatives to cadmium (which can be quite toxic in certain forms).
posted by tobascodagama at 11:22 AM on August 30, 2017 [1 favorite]

"The so-called "cyborg" bugs produce acetic acid, a chemical that can then be turned into fuel and plastic."

Oh, great.
posted by scottatdrake at 11:44 AM on August 30, 2017 [1 favorite]

"We have collaborators who have a number of strands of E. coli that are genetically engineered to take acetic acid as their food source and they can upgrade it into butanol and a polymer called polyhydroxybutyrate."

It's about time E. coli starts pulling its weight around here.
posted by Pope Guilty at 11:49 AM on August 30, 2017 [7 favorites]

It's a compostable plastic, though. (Which doesn't make a difference if it's just dumped in a landfill, but still.) Also, it's apparently used in dissolvable stitches?
posted by tobascodagama at 11:49 AM on August 30, 2017

So they can't outcompete bacteria in the wild.

That's one really large benefit of using cadmium as a feed metal here. Cd is pretty rare in surface soils, with the exception of downstream industrial contamination, smelters, battery plants and the like. So that means these bacteria will have trouble escaping into the natural environment and disrupting the existing consortia.
posted by bonehead at 11:59 AM on August 30, 2017 [4 favorites]

It's about time E. coli starts pulling its weight around here.

Sounds like E. coli finally got its shit together.
posted by Strange Interlude at 12:01 PM on August 30, 2017 [21 favorites]

So we're only "self-reproducing" away from grey goo then?

I don't think so. This isn't about microscopic von Neumann self-replicators, but about finding new pathways in existing bacteria.
posted by bonehead at 12:03 PM on August 30, 2017

They mentioned Mercury and we know a lot of places that are polluted with Mercury.
posted by Oyéah at 12:05 PM on August 30, 2017

I don't get how the crystals on the bacteria helps them with this conversion. Can someone explain this to me using very simple terms and/or analogies?
posted by any portmanteau in a storm at 12:06 PM on August 30, 2017

We've been able to get bacteria and algae to make fuels for quite a while now; the problem has always been scalability. This is a neat trick, but until they can make it work on an industrial scale it doesn't matter for any practical purposes. I wish them luck, but I don't see anything in this article that makes me think they've cracked that problem.
posted by Anticipation Of A New Lover's Arrival, The at 12:12 PM on August 30, 2017 [4 favorites]

More technical details in this IEEE article.
posted by King Sky Prawn at 12:12 PM on August 30, 2017 [1 favorite]

I don't get how the crystals on the bacteria helps them with this conversion. Can someone explain this to me using very simple terms and/or analogies?

Photon hits crystal, electron pops out of crystal, bacteria uses electron to split carbon dioxide and water. Bacteria excrete acetic acid as a store of energy much like a plant builds glucose. The more electrons you give a bacteria the more atoms of acetic acid they make. We know how to make materials that have wide band gaps and can efficiently harvest electrons from the photons.
posted by Talez at 12:12 PM on August 30, 2017 [6 favorites]

Why do I immediately think acidified, electric, oceans? Then the wabes will surely be brillig and slithy. I know, I know top men cleaning the labs, will surely not put this stuff down the drains. Oh my god mom, I coughed up another one of those mini solar panels.
posted by Oyéah at 12:13 PM on August 30, 2017 [2 favorites]

Why do I immediately think acidified, electric, oceans? Then the wabes will surely be brillig and slithy. I know, I know top men cleaning the labs, will surely not put this stuff down the drains. Oh my god mom, I coughed up another one of those mini solar panels.

The bacteria need a source of cadmium to create the cadmium sulfide crystals which give them the electrons needed to maintain the reaction.
posted by Talez at 12:16 PM on August 30, 2017 [1 favorite]

This video from the ACS made it clear for me, linked in King Sky Prawn's linked IEEE article. It's a 2 minute animation with a voiceover.
posted by ambrosen at 12:45 PM on August 30, 2017 [2 favorites]

The bacteria need a source of cadmium to create the cadmium sulfide crystals which give them the electrons needed to maintain the reaction.

Fun(?) fiction premise: turns out there's enough of it in people from industrial pollutants!
posted by curious nu at 12:50 PM on August 30, 2017

They also said these bacteria use other elements besides Cadmium, which is relatively rare in the environment, they mentioned Mercury or Lead, as items in the environment these bacteria are drawn to. So potentially the cadmium engineered bacterium, lacking that, might choose something else in the environment that is common, and go to work with that. This is what I mean.
posted by Oyéah at 12:58 PM on August 30, 2017

I assume it's a small step from this to self-vinegaring fish and chips. After years of trying to wean him off a land line and cassette tapes, this would be, like, my dad's killer app of technology.
posted by Quindar Beep at 12:59 PM on August 30, 2017 [7 favorites]

That would be a good app, actually! Dip fish in bacterial bath. Bacteria clean all of the toxic metals out of the fish and infuse the fish with vinegar. Cook the fish, killing the bacteria. Nom, nom, nom. And if you want some nice vinagary sushi, then the bacteria clean you out of toxic metals before you die of a severe iron deficiency, because oh, poop, unintended consequences. So I changed my mind. Do not want. But hey, free energy for whatever the next species to evolve turns out to be.
posted by It's Raining Florence Henderson at 1:11 PM on August 30, 2017 [2 favorites]

One of the other reasons that they are not likely to dominate ecosystems in the wild is that making acetic acid with solar energy is not likely to be as evolutionarily advantageous as making more of your species.

Now, so, they might evolve a strain of Cd-scavenging bacteria that don't pump out acetic acid. That actually... you know, that would be likely to concentrate Cd, that might be useful just for cleaning up soil and water. (We have to find and harvest the Cd-y goo, but that's not as difficult as sorting it molecule by molecule.)
posted by clew at 4:20 PM on August 30, 2017 [1 favorite]

Also, they're putting out acetic acid but they're making it with CO₂ which is the thing that is acidifying the oceans right now as we speak. I'm not enough of a chemist to be able to say what the net result would be, though.
posted by Anticipation Of A New Lover's Arrival, The at 4:27 PM on August 30, 2017 [1 favorite]

"We've been able to get bacteria and algae to make fuels for quite a while now; the problem has always been scalability. This is a neat trick, but until they can make it work on an industrial scale it doesn't matter for any practical purposes."

Literally exactly what people said about penicillin! In 1942, the US made enough penicillin for 10 doses. In 1943, a strain suited to mass production was discovered (on a moldy cantaloupe), and cultivated at the USDA lab in Peoria. In 1945, 646 billion doses were produced.

You need some motivated guys trying lots of different things ... which it sounds like these guys are, and global warming is certainly motivating. People sometimes talk about how the economy needs to be on a war footing to deal with the challenging of global warming, and I get hope from the fact that a lot of science labs already seem to be there, throwing every possible crazy answer at the wall to see what sticks.
posted by Eyebrows McGee at 9:08 PM on August 31, 2017 [5 favorites]