13 ms·
An enzyme that digests plastic could boost recycling
- fredley 8y agoI'm fascinated by this. It took 60 million years after trees evolved for microbes to evolve that could digest them[1]. The resulting strata of undigested tree are now most of our coal. Now of course, if a tree dies and is left where it fell, it is usually digested entirely in a number of years by microbial life. What would happen if a microbe evolved that could feed itself from plastic? And what if it got out of the lab? Imagine all the plastic items in the World suddenly as susceptible to rot as wood. It would fundamentally change almost every aspect our existence, in a very short amount of time. [1]: http://phenomena.nationalgeographic.com/2016/01/07/the-fantastically-strange-origin-of-most-coal-on-earth/ http://phenomena.nationalgeographic.com/2016/01/07/the-fanta...
- k_ 8y agoIt would be awesome if we could unleash something like this in our oceans without doing harm to the ecosystem (would be hard to do more harm that what we are already doing with plastic, but still).
- spodek 8y agoIt would be awesome if we ourselves could interact with the ocean without doing harm to the ecosystem.
- uhhyeahdude 8y agoYes, yes it would. Systems thinking is hard. (Eco)Systems thinking is nearly maddening. Even if one could account for many variables (for an acceptable value of many), one would still have to deal with everything else, which often includes stupidity, irrationality, politics, emotion, villains... Nature makes many errors, but at least it isn't stupid; those errors result in the adaptations that make the world work. This process involves a lot of death, but it works. Or, it did. I am somewhat familiar with ecosystems and environmental restoration, and I don't mean to discourage anyone from positive thinking; in this case, however, I really think people need to try to comprehend the mechanisms before experimenting. I reiterate: systems thinking is hard.
- meric 8y agoThe best way to unleash it in our system without doing harm to the ecosystem is to be patient. There is energy content in the plastic and over 100-200 million years the chance is extremely high Earth’s ecosystem will adapt to the abundance of plastic.
- jon_richards 8y agoThe issue has never been whether the ecosystem will adapt. It has been how well we will. If plastic in the ocean kills/renders toxic all the fish, that will be an issue for us. The ecosystem? It will be fine.
- kjjw 8y agoThe idea that ecosystems are self balacning and always bounce back is discredited science. It’s still a popular idea in mainstream discussion, though.
- deleted 8y ago[deleted]
- 3chelon 8y agoIs it really discredited? What are your sources? I tend to believe (with no actual evidence, since there is none), that the ecosystem will adapt to whatever damage we do to it using the tried-and-tested method of natural selection. Most mainstream conversations about this are entirely anthropocentric and assume we have to be part of that equation. They always assume we're the top of the food chain. But whereas most of us will never be eaten by a tiger, pretty much all of us will be eaten by bacteria one day. Microbial life has been around for far longer, and is far more abundant than we can ever hope to be. I don't think much we can do will fundamentally alter that balance.
- foota 8y agoIt's a hyperbolic example, but I doubt life on Earth would adapt to being engulfed by the sun, for one
- endymi0n 8y agoI had the same exciting thought before it dawned on me that we usually choose plastics for a reason. Imagine water bottles breaking down in the store. Imagine protective coatings of ships breaking down. While I'd be happy for the mess we created in the oceans, I'm unsure if this would just trigger another arms race for more indestructible materials — that would clog the oceans once again.
- chiefalchemist 8y agoWe chose plastics because it was cheaper. Yes, there are other benefits. Unfortunately, no one asked, "If this stuff doesn't decompose, then what?" to assess that risk vs the benefits. Without that answer the use of plastics should have been mitigated a la nuclear fission. Instead, micro bits of plastics are everywhere; the oceans and their ecoayatem are compromised. Etc. For what? Convenience and a few cents?
- acdanger 8y agoI ask myself the same question about our current techno-commercial landscape.
- spodek 8y agoThe main reason is not having to account for externalities. As long as someone else has to pay for cleaning up, why bother thinking about it when you can keep the short-term profits?
- fredley 8y agoMy favourite what if: What if we engineer such bacteria to survive in our gut?
- pbhjpbhj 8y agoManufacturers don't really choose plastic for longevity, they choose it because it's cheap and easy to work with (ie plastic [adjective]). There are already biodegradable alternatives for almost everything but they add a few pence to the cost of a happy meal, say, and aren't a strong enough differentiator at the point of sale for profit-driven companies to care about it. The alternatives don't instantaneously degrade, they usually need proper composting to quickly degrade (high temperatures, aerobic). We've used compostable nappies that when properly composted can degrade fully in a year - they're similar in use (save not releasing "gel balls"), don't appear to have a significantly depleted shelf-life. I don't know why such things aren't mandated TBH.
- Orphis 8y agoAbout 20 years ago, I did a one week internship as a teenager in some lab that worked exactly on this. They were trying to grow and select enzymes that could process different types of oil that frequently occurred in spills. The tricky part was to make sure they only targeted what was in the ocean. You didn't want them to start propagating into the oil tanks in boats, or start processing all the random plastics that make up boats or various infrastructure. I remember on my last day, they had some really good results with some samples that processed some oil really well and were quite excited. I then left, and have no idea if they managed to reproduce the results or not.
- JulianMorrison 8y agoMeh, make them eat all the oil. Civilization could use the kick in the ass to switch to electrics.
- majewsky 8y agoWhen they eat the oil, how do they metabolize it? If they end up producing CO2 like ICEs do, that would not be a productive measure against climate change at all.
- JulianMorrison 8y agoGiven it was going to be burned, that's six of one and half a dozen of the other, except that if the bugs eat it, the humans have to change their behaviour.
- simias 8y agoPlastic pollution has tons of drawbacks but at least it doesn't contribute to global warming since it effectively stores carbon. Having all the plastic in the world start rotting away and releasing carbon into the atmosphere might to a lot of harm. Especially if other petrol byproducts like the bitumen of our roads are concerned. You're right however that if these products start becoming effectively unusable (or less usable) because they now rot it would make alternative solutions a lot more attractive, but we already have so much petrol byproducts in the wild that the transition would be pretty nasty.
- neolefty 8y agoThe organisms would probably need micronutrients as well, such as iron or copper. Advantage: We can control their spread—target them at the Garbage Patches Disadvantage: More expensive to deploy, since you have to also sprinkle fertilizer for the cleanup to be effective.
- Hoasi 8y agoThis could be a great plot for a sci-fi novel.
- adrianN 8y agoIt's been done at least once: https://en.wikipedia.org/wiki/Earth_Maiden_Arjuna https://en.wikipedia.org/wiki/Earth_Maiden_Arjuna
- King-Aaron 8y agoSee also Larry Niven's Ringworld https://en.wikipedia.org/wiki/Ringworld https://en.wikipedia.org/wiki/Ringworld
- fredley 8y agoI've tried to write some short stories on the theme but I'm no writer, I could never get something I was happy with.
- campbellmorgan 8y ago>I could never get something I was happy with You sound like a writer! Keep going
- cooperadymas 8y agoPossibly a slight spoiler, but Andromeda Strain does exactly this. https://en.wikipedia.org/wiki/The_Andromeda_Strain https://en.wikipedia.org/wiki/The_Andromeda_Strain
- JohnL4 8y agoClots blood and eats rubber, but ok.
- adrianN 8y agoWe build lots of durable structures out of wood. I don't think it would be a very serious problem.
- mkj 8y agoLots of modern construction wood is laminated together with plastic. I'm sure people would adapt though.
- vanderZwan 8y agoI expect this would also make the material scientists happy for being given a new challenge.
- sohkamyung 8y agoThe article only mentions the enzyme breaking down polyethylene terephthalate (PET), not other kinds of plastics. So those would be safe from the enzyme. Of course, the enzyme could be engineered to break down all kinds of plastics but I doubt that is biologically possible. It would become like the old joke of the 'acid that can dissolve anything', at which point the question becomes, "So what do you use to contain the acid?" :-)
- TeMPOraL 8y ago> It would become like the old joke of the 'acid that can dissolve anything', at which point the question becomes, "So what do you use to contain the acid?" :-) Tangential: not an acid, but antimatter has similar properties, and you contain it in a magnetic trap ;).
- sohkamyung 8y agoI think not. Magnetic traps can only contain anti-matter ions, not neutral anti-matter atoms or molecules.
- TeMPOraL 8y agoJust a shorthand. Ions are good enough to... dissolve regular matter. Into gamma rays.
- rflrob 8y agoYou can actually use multipole magnets to capture neutral anti-hydrogen. Not that they're trapping a lot of neutral anti-hydrogen, but some. [1] https://en.wikipedia.org/wiki/Antihydrogen#Low-energy_antihydrogen https://en.wikipedia.org/wiki/Antihydrogen#Low-energy_antihy...
- sohkamyung 8y agoThanks for that. I forgot about the spin magnetic moment. Whether this works on other atoms or molecules depends, of course, on how strong this field is.
- lawlessone 8y ago>What would happen if a microbe evolved that could feed itself from plastic? it did. also plastic degrades in UV light and due to weather so it probably wouldn't be that much different to now.
- raverbashing 8y agoInteresting paradox. Either making cellulose is easier than breaking it up (even under the sun/rain/etc) or maybe bacteria "didn't see a reason" to tap that energy source (hence not evolving in that direction).
- m12k 8y agoOr maybe it required a leap of evolution in a direction in which there was no other evolutionary pressure to take the first steps and make subsequent steps smaller and thus more likely? Complex mutations are probably more rare if the environment does not facilitate doing it bit by bit.
- qbrass 8y agoCellulose was hard to break down, so when bacteria found a way to do it, they had no competition for that food source and millions of years worth of it just sitting around to feed on.
- eojrgherkghj 8y agoIt's not so much the cellulose, it's the lignin that makes wood so hard to digest. Fungi resort to producing peroxides instead of attacking it directly with tailored enzymes
- klmr 8y agoThere is no paradox: Plastics have really only been around for less than a century. Modern plastics are all synthetic, and sufficiently distinct to all naturally occurring biopolymers. So bacteria only had ~100 years to evolve this capability. Compare this to the ~60 million years it took to evolve wood-digesting enzymes efficiently. The situation isn’t entirely comparable, since these enzymes wouldn’t have to evolve “from scratch”. Hence why researchers may have found rudimentary capabilities in the wild. But evolving this from the basics to an efficient food source naturally would take a very long time indeed.
- akavel 8y agoUm, the article does actually explicitly mention such a microbe, as that is the origin of the titular enzyme! Do I misunderstand something, or you didn't read the article? It's hard for me to understand the "What would happen if a microbe evolved..." question when the article literally says: "[The] PETase [enzyme] is secreted by a plastic-munching bacterium called Ideonella sakaiensis 201-F6. This bug was discovered in 2016 at a PET-bottle recycling plant in Sakai, Japan."
- sarabande 8y agoI think a more charitable interpretation of the parent comment was that of a doomsday thought experiment/rhetorical question: What would happen if these bacteria evolved to really be able to cause damage one day? The article only briefly remarks: > If these hurdles can be surmounted, though, PETase might make a dent in the scourge of plastic waste.
- goodmachine 8y agoFWIW, this 'doomsday scenario' is roughly the plot of a 1979 Judge Dredd episode (which I remember fondly) - featuring a world in which support bridges were made of 'plasteen' under attack from a novel bacterium: SOMETHING'S EATING IT AWAY The Great Plasteen Disaster https://dreddalert.blogspot.co.uk/2014/01/judge-dredd-great-plasteen-disaster.html https://dreddalert.blogspot.co.uk/2014/01/judge-dredd-great-...
- JohnL4 8y agoAlso, a book published in 1972, _Mutant 59: The Plastic Eaters_. https://www.goodreads.com/book/show/2368220.Mutant_59 https://www.goodreads.com/book/show/2368220.Mutant_59
- cavanasm 8y agoAlso (sort of) the crux of one of my favorite horror manga, Biomeat: Nectar, which is about a genetically engineered animal that eats "garbage" (basically anything but metal, glass, and stone IIRC) and can be harvested for food, but escapes from the garbage plants and starts going after people. They're not microbes though, but more like nightmare fuel looking bugs about the size of a face, with the mouth on the bottom, and they reproduce via budding (like a hydra).
- mseebach 8y ago> Imagine all the plastic items in the World suddenly as susceptible to rot as wood. It would fundamentally change almost every aspect our existence, in a very short amount of time. Hardly. Some usages of plastic would need to be altered, but most would be fine. The conditions in which wood will rot are very specific (the forest floor, basically) and reasonably easy to avoid, surely something similar will be true for rotting plastic. Pre plastics, practically anything, including all kinds of liquids, was stored in wooden barrels.
- Sharlin 8y agoTo be fair, wooden things—were they barrels, ships, or houses—absolutely require protection and maintenance to prevent them from rotting. We became pretty good at that because wood was a crucial raw material for millennia. We haven’t thought about how to protect plastics because we’ve accustomed to plastics not needing protection.
- Moru 8y agoPlastics need protection from a lot of things, cold, heat, sun not to mention physical wear. Some older, cheaper plastics just crubles to dust when you touch them.
- therealdrag0 8y agoIs crumbled plastic part of the micro-plastics we hear about polluting the ocean?
- Kroniker 8y agoYes! In fact most plastic is relative susceptible to UV radiation, which facilitates that "crumbliness" in the ocean.
- kazinator 8y agoThe conditions under which wood rots: untreated + outdoors.
- georgecmu 8y agoThat's a cute story, but the evidence is lacking. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4780611/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4780611/ The Carboniferous−Permian marks the greatest coal-forming interval in Earth’s history, contributing to glaciation and uniquely high oxygen concentrations at the time and fueling the modern Industrial Revolution. This peak in coal deposition is frequently attributed to an evolutionary lag between plant synthesis of the recalcitrant biopolymer lignin and fungal capacities for lignin degradation, resulting in massive accumulation of plant debris. Here, we demonstrate that lignin was of secondary importance in many floras and that shifts in lignin abundance had no obvious impact on coal formation. Evidence for lignin degradation—including fungal—was ubiquitous, and absence of lignin decay would have profoundly disrupted the carbon cycle. Instead, coal accumulation patterns implicate a unique combination of climate and tectonics during Pangea formation. from another article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4780642/ https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4780642/ There is a long-invoked but incorrect (9) perception that lycopsid-dominated forests were the main source vegetation of Carboniferous coals because of the abundance and resistance to decomposition of lycopsid periderm (bark) (e.g., refs. 1, 4, and 5). Thus, lycopsid dominance supposedly was essential for formation of the economically important Carboniferous coals. In what initially appears to support this perception, Nelsen et al. (8) use spatiotemporal trends in Phanerozoic organic-rich terrestrial sediments to demonstrate peak North American coal production during intervals when lycopsids dominated Euramerican tropical forests. Most dominant Carboniferous wetland plants, however, produced little wood, and the arborescent lycopsids were no exception (10). The towering lycopsid stature was made possible by unlignified periderm rather than lignin-rich wood. Therefore, they contributed less lignin to peat accumulations than woody plants, which were episodically abundant, although rarely dominant, in Pennsylvanian–early Permian tropical lowland basins (9, 11). Nelsen et al.’s (8) scientific twist to the hypothesized lycopsid–lignin–coal linkage—that is, documenting coincidence in peak coal production and lycopsid dominance, when lignin would have contributed minimally to peat accumulation—weakens the argument that the emergence of lignin synthesis was one criteria for intensified terrestrial organic carbon sequestration in the Carboniferous. Large-scale peat accumulation further requires suppression of organic matter decay, of which woody tissue, in the absence of efficient lignin-degrading fungi, has been considered the source (5). Nelsen et al. (8) challenge this view by documenting fungal and bacterial degradation of Paleozoic lignified tissues and, conversely, evidence for abundant unlignified organic matter in many peats. Nelson et al.’s study, building on decades of paleobotanical research, thus unequivocally demonstrates that pre-Permian lignin resistance to decay, and thus preferential biochemical composition of vegetation, was not the key to high rates of peat accumulation 325–300 Myr ago. Intriguingly, lignin’s legacy in Carboniferous peat accumulation may be moot: Nelsen et al. (8) point out that the evolution of Agaricomycetes fungi, based on reassessment of phylogenomic evidence (7), is permissible as far back as the Devonian (420–359 Myr), thus potentially closing the evolutionary lignin–fungal gap. If correct, then a closer temporal association between the onset of lignin biosynthesis and the evolution of lignin-degrading fungi suggests rapid evolutionary innovation in response to a novel resource. Nelsen et al.’s collective findings (8) further resolve a mass balance conundrum regarding the Carboniferous–Permian atmosphere. In a world with hypothesized abundant lignin, the absence of fungal-mediated degradation, in concert with widespread peat accumulation and burial, would have depleted atmospheric CO2 within a fraction of the proposed ∼120 Myr evolutionary gap. Large-magnitude CO2 degassing from volcanism, for which there is no clear evidence, would be needed to maintain the requisite long-term balance in total CO2 inputs and outputs to and from the atmosphere (1).
- devy 8y ago> Imagine all the plastic items in the World suddenly as susceptible to rot as wood. It would fundamentally change almost every aspect our existence, in a very short amount of time. Absolutely! The first thing came to my mind is the usage of polymers in construction industry (epoxy for joining material, coating for anti-corrosion measures) and the predominant PVC underground sewer lines and plumbing pipes. If those aren't as durable as we previously assumed, the rebuild/replacement is going to be catastrophic. (PS: I had almost had to replace the underground clay/cast iron sewer lines that's been there for 50 years and reaching the end of life for the material at our new home last year. The cost was astronomical and requires many town permits and time to even start the project. Thankfully we didn't have to!)
- dv_dt 8y agoIt's an interesting thought, but perhaps we should consider how susceptible we would actually be. We still build houses from wood, which can rot and be digested, but generally doesn't with a reasonable amount of maintenance. Even if an hyper effective microbe were to spread, the manner of spread is unlikely to be any more effective with respect to dispersion than others that e.g. attack wood.
- vanderZwan 8y ago> It took 60 million years after trees evolved for microbes to evolve that could digest them Go back further in time, and you'll discover that from the moment photosynthesis arrived on the scene and took over as an energy source, until a life-form evolved that could make use of the poisonous oxygen that was a byproduct of it, it took roughly 0.7 billion years[0]. Resulting in many, many cyanobacterial apocalypses in that time. We may have to come up with new (old) material solutions to many things, but on the whole I think that plastic-eating microbes are probably more of an apocalypse-averting scenario than an apocalypse-causing one. EDIT: to put that 0.7 billion years number into perspective, let's look at the age of life on Earth: > The earliest time that life forms first appeared on Earth is unknown. They may have lived earlier than 3.77 billion years ago, possibly as early as 4.28 billion years ago, not long after the oceans formed 4.41 billion years ago, and not long after the formation of the Earth 4.54 billion years ago. The earliest direct evidence of life on Earth are fossils of microorganisms permineralized in 3.465-billion-year-old Australian Apex chert rocks. Sticking to the confirmed existence of life, 0.7 billion years represents 20% of life's history on this planet. With conservative estimates 18%, and assuming it was there from very early on, 16%. Even if life has existed on this planet for as long as Earth itself has, then this still accounts for 15% of the history of life on this planet. Meanwhile, we likely split off from Chimpanzees around 12 million years ago, with modern humans not evolving until about 300-200 thousand years ago (which I still find mind-bogglingly recent), which is somewhere between 0.006 to 0.008%[3]. EDIT2: This makes me wonder if modern bacterial life-forms, if not all modern life-forms that we may consider simple and primitive, may not in fact be incredibly sophisticated compared to their ancestors of billions of years ago. I can imagine that they appear similar due to a particular solution already being stuck in a local optimum (say, shark body plans, or certain leaf shapes) but that on the genetic level the more recent life-forms might have evolved complicated systems of evolvability itself that lets them adapt much faster than before[4]. [0] http://www.patheos.com/blogs/daylightatheism/2009/02/bands-of-iron/ http://www.patheos.com/blogs/daylightatheism/2009/02/bands-o... [1] https://en.wikipedia.org/wiki/Earliest_known_life_forms https://en.wikipedia.org/wiki/Earliest_known_life_forms [2] https://en.wikipedia.org/wiki/Chimpanzee%E2%80%93human_last_common_ancestor#Current_estimates https://en.wikipedia.org/wiki/Chimpanzee%E2%80%93human_last_... [3] https://en.wikipedia.org/wiki/Timeline_of_human_evolution#Homo https://en.wikipedia.org/wiki/Timeline_of_human_evolution#Ho... [4] https://en.wikipedia.org/wiki/Evolvability https://en.wikipedia.org/wiki/Evolvability
- sytelus 8y agoI have been seeing articles on this topic for at least 5 years. What is stopping this from becoming actual practical process than just PR release that keeps poping up every now and then? Is there any real article on technical problems in this area that are still unsolved?
- Tepix 8y agoThe article states that a 100-fold increase in efficiency is required before it can be used.
- whistlerbrk 8y agoI worked on this during my undergrad in 2004. DARPA grant back then. Basically the military has to haul trash where ever they go or burn it, they can save money by embedding these enzymes directly into the plastic and turning it into fuel. Still hasn't happened.
- neolefty 8y agoLikely, the organisms that make it require other nutrients as well, that aren't found in plastic. So you can't just go drop a few on the Great Garbage Patch unless you also sprinkle fertilizer along with it.
- cooper12 8y agoWe get an article like this every week. Wake me up when any of these miracle solutions actually get put into practice. I'm still waiting for those graphite batteries btw.
- dschuetz 8y ago"Digesting" enzymes? "Boost recycling"? That sound like a typical click bait. It's actually an artificially engineered enzyme formerly discovered in certain bacteria which is able to break PET molecules. Lots of potential, moving on.
- jimjimjim 8y agothere was a judge dredd story way way back where the whole city was falling apart because of something airborne that was eating plastic. are we sure we want this?
- JulianMorrison 8y agoWe should engineer this into slime mold and release it into the wild to eat litter.
- mgeorgoulo 8y agoLife has an awesome way of turning disaster into opportunity!
- deleted 8y ago[deleted]
- bawana 8y agoAnyone remember Andromeda strain? A bug that digests plastic was responsible for the crash of a plane. Bacteria are too small to contain. They'll get out somehow - on the worker's clothes, etc. And then they'll wreak havoc (armageddon?) on this plastic world.
- rough-sea 8y agoCan someone link to a pdf of the actual paper? Harry P. Austin el al., "Characterization and engineering of a plastic-degrading aromatic polyesterase," PNAS (2018)
- gadders 8y agoDon't forget the caterpillars that can do this as well: http://www.bbc.co.uk/news/science-environment-39694553 http://www.bbc.co.uk/news/science-environment-39694553
- Coincoin 8y ago> At the moment, a litre of a solution of even the improved enzyme would break down just a few milligrams of plastic per day. Its plastic-digesting ability must therefore be improved by a hundredfold or more to be commercially useful. Good! The last thing we need right now is yet another source of CO2. I say bury the thing, it's that much carbon sequestered for a few hundred years.
- drdeadringer 8y agoWhat I have yet to understand is what happens in a few hundred years when all this sequestered CO2 becomes not sequestered, and how this is not more "kick the can".
- umanwizard 8y agoIf our civilization survives another few hundred years, we’ll be incredibly lucky.
- Coincoin 8y agoIt's pretty obvious what will happen; it will transform into CO2 into the atmosphere. But at least it will have given us a few hundred years to figure out instead of piling over the present mess.
- drdeadringer 8y agoI'm all optimistic about technological innovation, but I have a doubt regarding the will of the (at least politically) great and powerful. Is this where the Free Market comes in a la Musk's future ilk?
- kwhitefoot 8y agoDoes anyone remember the first Doomwatch episode, the Plastic Eaters?
- decebalus1 8y agoCan't help be reminded of this (awesome) book [1] where a bacterium is engineered to eat PCBs and released in the wild without proper testing, leading to very interesting side-effects. I wonder what byproduct of this digestion would be. I don't want to sound like a luddite but remember BPA? [1] https://en.wikipedia.org/wiki/Zodiac_(novel) https://en.wikipedia.org/wiki/Zodiac_(novel)
- bcheung 8y agoGeorge Carlin was right. https://www.youtube.com/watch?v=NBRquiS1pis https://www.youtube.com/watch?v=NBRquiS1pis
- flarg 8y ago2000AD was at least as prophetic ... http://dreddalert.blogspot.co.ke/2014/01/judge-dredd-great-plasteen-disaster.html?m=1 http://dreddalert.blogspot.co.ke/2014/01/judge-dredd-great-p...