BacillaFilla!

Engineered Bacteria Can Fill Cracks In Aging Concrete

"BacillaFilla," as the researchers call it, is a genetically modified version of Bacillus subtilis, a bacteria commonly found in common soil. The researchers have tweaked it's genetic properties such that it only begins to germinate when it comes in contact with the highly-specific pH of concrete. Once the cells germinate, they are programmed to crawl as deep as they can into cracks in the concrete, where quorum sensing lets them know when enough bacteria have accumulated.

That accumulation lets the bacteria know they've reached the deepest part of the crack, at which point the cells begin to develop into bacterial filaments, cells that produce calcium carbonate, and cells that secrete a kind of bacterial glue that binds everything together. Once hardened, the bacteria is essentially as strong as the concrete itself, restoring structural strength and adding life to the surrounding concrete.

The bacteria also contains a self-destruct gene that keeps it from wildly proliferating away from its concrete target, because a runaway patch of bacterial concrete that continued to grow despite all efforts to stop it would be somewhat annoying.

Previously.

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33 Responses:

  1. dr_memory says:

    Needs a 'doomed' tag for when an escaped colony mutates to germinate when in contact with human flesh.

    • jered says:

      The wheels come off of all these systems pretty fast; it turns out (for good reason) that it's hard to keep energy-expensive molecule production in bacteria. I'm not terribly concerned about safety for non-disease agents. When I was a research scientist I was working on the building blocks for these sorts of things... I didn't have the patience to continue in bio-engineering, but I'm glad applications are finally becoming realistic!

    • lloydwood says:

      Can they tweak the bacteria and the pH setting to only work on human teeth, and fill fissures with calcium carbonate? (My, these ads on pressing 'Preview' are annoying.)

  2. alex_victory says:

    a runaway patch of bacterial concrete that continued to grow despite all efforts to stop it would be somewhat annoying.

    Ye gods, understatement of the year.

    • mcity says:

      It'd be like The Blob, except grey and hard. But enough about setups to double entendres.

    • elusis says:

      Reminds me of some SF book I read as a teen about a bio-engineered bacterium that ate petroleum. It was designed to clean up oil spills, but then some got loose and whoops, there goes the world's supply of crude.

      See also Cat's Cradle and Ice Nine.

      • badc0ffee says:

        What book was that?

        • elusis says:

          Beats me - wish I could remember.

          • option12 says:

            zodiac?
            an eco thriller

            neal stephenson.

            also has nitrous trash bags.

          • killbox says:

            Was it Bruce Sterling's Heavy weather?

            • elusis says:

              A little poking around has suggested this title before, but I didn't think I'd read any Sterling.

              I also remember something about most of the fertile women dying off, and one woman being sealed up in a little pod or something. But I was pretty young, and not a hard SF reader usually, so it's gotten very blurry with time. I think I tried whatwasthatbook once but didn't get any joy.

              (For all I know I've conflated two books I read at one point...)

      • krfsm says:

        "Mutant [something] - The Plastic Eater" maybe? May have had Doomwatch in the title too.

        • elusis says:

          See above. My memory of the thing is so dim that I could be confabulating, or for that matter, I could have read the back of a few different paperbacks at the local library and stored that one in my memory as if I read it. Premise obviously stuck with me, though.

  3. The bacteria also contains a self-destruct gene that keeps it from wildly proliferating away from its concrete target...

    I like how they just throw that in there. "Oh, don't worry, it's got a Self-Destruct Gene(tm!)"

    Uh... HOW does the self-destruct gene work? How reliable is it? How likely is it that it will be disabled or lost through random mutation? Piddling questions, I know...

  4. pavel_lishin says:

    I want to spread some on concrete art.

  5. mackys says:

    Can't wait until someone inhales some and it starts concrete-coating the inside of their lungs!

    • elusis says:

      Which part of "it only begins to germinate when it comes in contact with the highly-specific pH of concrete" was unclear?

      • mackys says:

        I'm curious to know exactly how that works, and what kind of things could go wrong with it. I'm real skeptical that they've managed to completely cut off any possibility of any kind of mutation that would allow the bug to live in less alkaline environments.

        From what I can see on Wikipedia, unmodified http://en.wikipedia.org/wiki/Bacillus_subtilis is happy to live in human bodies. (Also evidently the stuff is used to ferment natto - bleah!)

        I think a better argument might be that while it would happily live in a human body, it won't ever reproduce enough to get to the point of starting to calcify. But even that one, I'd want a lot of testing done before I'd start believing it.

        • mentallill says:

          Short answer: go to http://2010.igem.org/Team:Newcastle

          How do you get from "B. subtilis is not a human pathogen" to "it's happy to live in human bodies"? It's happy to live on human skin, maybe, where the immune system leaves it alone, but if there is a place on the logical inside of your body (away from the GI tract) where bacteria thrive well enough to start engaging in quorum sensing, that means you're dying of septicemia. Or meningitis, or at the very least you have a urinary tract infection.

          To be happy, and do its thing, the modified B. subtilis strain needs oxygen, urea, and dissolved calcium. It will then produce calcium carbonate, which will dissolve in acidic conditions (eggshells and vinegar). There are other bacteria that will infect your urinary tract or bladder and perform the same reaction that's being utilized here, but they don't need oxygen.

          (Note that "but the reaction is expensive" thing is, uh, wrong. Urea is a high-energy molecule, and if you metabolize it all the way to nitrogen, water, and CO2 you come out way ahead-even ammonia can be used to fuel combustion engines. The human body spends a lot of energy on the production and concentration of urea, to get rid of ammonia (basic) which would otherwise wreck it. From a chemical point of view it would be more obvious to use the (basic) ammonia as fuel and produce (neutral) nitrogen gas, (acidic/neutral) CO2, and (neutral) water, but I think denitrification reactions never evolved in eukaryotes. In other words, we keep rocket fuel in our bladders and rely on our immune system not to let any bacteria get there and eat it.)

          • killbox says:

            If what you are saying is true, and it gets into the gut to the extent others are fearing.. one could literally "Shit Bricks"

          • jwz says:
              "We keep rocket fuel in our bladders and rely on our immune system not to let any bacteria get there and eat it."

            That's it, from now I'm phrasing it as, "Man, I've got piss like a Stage Tree."

      • mentallill says:

        Summary: http://2010.igem.org/Team:Newcastle has the actual project, and http://2010.igem.org/Team:Newcastle/safety has more on safety than the sentence you quote, which is stupid.

        (Sorry, I'm nitpicking. The project is safe and sensible and they've thought about all this, and then some journalist wrote down a sequence of words that sounded good but do not, actually, mean what the journalist thought.)

        Uhm, if you ask that specific question ... what is "highly-specific pH of concrete" supposed to mean? Concrete starts out at a pH of about 10, when it's equivalent to (diluted) (basic) calcium hydroxide. Over the years, that turns into the equivalent of calcium carbonate, which is neutral-ish, and the pH falls to 7-8. If exposed to sulfides, it ultimately turns into acidic calcium sulfate, though for reinforced concrete, the rebar will start rusting well before the pH falls all the way into the "acidic" region. Oh, and all of that is dependent on temperature, because the Gods Who Invented The pH Scale made it so it varies by a half a unit depending on whether you're in the shade or not.

        Also, context is good: "it's genetic properties such that it only begins to germinate when it comes in contact with the highly-specific pH of concrete". Has that sentence been checked for accuracy? No, it hasn't even been checked for grammar.

        The pH of concrete isn't "highly specific", as though it were precisely 8.724 and the bacteria would start dying once that last digit changed: it's a little unusual, because it's in the basic range, but urine will go through the same pH range, starting out neutral, then turning basic as urea is converted to ammonia. You can make pretty much anything have the same pH as your concrete sample by peeing on it and waiting a little. Why do I bring up urea? Because that's what they use. The bacteria they use is the very same species of bacteria that is responsible for making the products of public urination smell as horrible as they do, and if they produce a grey-goo type catastrophe and a strain escapes that does so ultra-efficiently, maybe that will help those despicable people who do it (and have alternatives) realize that there's a connection between peeing at five and stench at seven.

  6. hairyears says:

    As other commentators pointed out, it's difficult to keep bacteria producing an 'expensive' molecule: there is a powerful selection pressure to direct the energy and resources into reproduction and, by the inevitable processes of evolution, they will have ceased do make Calcium Carbonate within a month.

    I need hardly point out that the one-in-a-billion bacteria with a defective 'suicide' gene will be evolutionarily-favoured.

    I hope that the metabolic by-products of this new concrete-dwelling organism are not damaging to concrete.

  7. strspn says:

    Trained bacteria are the new flea circus.

  8. amaranthyne says:

    Now I have learned about quorum sensing. Fascinating.

  9. jklsdf says:

    Sounds a lot like the melding plague.