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Science

A French Company Is Using Enzymes To Recycle One of the Most Common Single-Use Plastics (technologyreview.com) 64

In late September, Carbios, a French startup, opened a demonstration plant in central France to test the use of enzymes to recycle PET, one of the most common single-use plastics and the material used to make most beverage bottles. MIT Technology Review reports: While we've had mechanical methods for recycling some plastics, like PET, for decades, chemical and enzyme-based processes could produce purer products or allow us to recycle items like clothes that conventional techniques can't process. [...] Carbios's new reactor measures 20 cubic meters -- around the size of a cargo van. It can hold two metric tons of plastic, or the equivalent of about 100,000 ground-up bottles at a time, and break it down into the building blocks of PET -- ethylene glycol and terephthalic acid -- in 10 to 16 hours. The company plans to use what it learns from the demonstration facility to build its first industrial plant, which will house a reactor about 20 times larger than the demonstration reactor. That full-scale plant will be built near a plastic manufacturer somewhere in Europe or the US, and should be operational by 2025, says Alain Marty, Carbios's chief science officer.

Carbios has been developing enzymatic recycling since the company was founded in 2011. Its process relies on enzymes to chop up the long chains of polymers that make up plastic. The resulting monomers can then be purified and strung together to make new plastics. Researchers at Carbios started with a natural enzyme used by bacteria to break down leaves, then tweaked it to make it more efficient at breaking down PET. Carbios estimates that its enzymatic recycling process reduces greenhouse gas emissions by about 30% compared to virgin PET. Marty says he expects that number to increase as they work out the kinks. In a recent report, researchers estimated that manufacturing PET from enzymatic recycling could reduce greenhouse gas emissions between 17% and 43% compared to making virgin PET. The report wasn't specifically about Carbios, but it's probably a good estimate for its process, according to Gregg Beckham, a researcher at the US National Renewable Energy Laboratory and a co-author of the report.

Carbios's product is about twice as expensive as virgin PET, Marty says. By comparison, mechanically recycled PET is only about 50% more expensive than virgin. Marty points out that Carbios's PET would still only cost about two cents for a small, clear plastic bottle, which he argues is a relatively small expense for manufacturers. Companies may be willing to pay. In a press release earlier this year, Carbios revealed demonstration bottles from partner brands that included PepsiCo and Nestle. Carbios recycled discarded plastic and handed it off to the companies, which used it to make new bottles. Eventually, enzymatic recycling may be able do things that mechanical recycling can't, like recycle clothes or mixed streams of plastics.

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A French Company Is Using Enzymes To Recycle One of the Most Common Single-Use Plastics

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  • by DethLok ( 2932569 ) on Thursday October 07, 2021 @02:48AM (#61868473)

    Yes please!

    Sign me up, I'll pay that $0.02 extra if it reduces plastic waste.

    • I'm so used to the comments system on YouTube that for a fraction of a second here I was looking for the "upvote" button to your comment.

      Heck, make it the same as the aluminium cans: five cents.

      • It is the same here in Germany and I think France too.
        25 cents for a can or a single-use plastic bottle. 15 cents for a multi-use plastic bottle and normal glass bottles. 7 cents for a half-liter glass bottle (typical for beer bottles).
        (Unless they are juice, for some reason.)

        Yes, if you got big bags of thoe bottles collecting behind your kitchen door or something, you might have a fortune right there. 400 bottles is 100 Euro. I knew a (poor) guy who literally used it as a savings account. :-D

    • That's not how things work. A 2 cent increase in the manufacturing cost will be used to justify at least $0.50 if not a full $1.00 extra.
    • by flink ( 18449 )

      How about adding a $0.05 deposit on plastic bottles as many states do for aluminum?

    • You already do, mate. :)

      You already do.

      (Soda costs, at most, a tenth of what you're paying.)

  • by MacMann ( 7518492 ) on Thursday October 07, 2021 @02:54AM (#61868479)

    I remember quite clearly my chemistry professor at university saying we should not be recycling plastics, we should just burn them for electricity.

    There's energy in plastic that can be recovered by burning it. The places we can burn this for energy can be found in most any city, a power plant. The argument for burning the plastics my professor made was that it takes a lot of energy and effort to truck this plastic around, then recycle it when it is really easy to just burn the old plastic and then make new plastic for new plastic items.

    The fine article is yet another example to prove my chemistry professor right. We should burn plastics for fuel. It's cheap, easy, and better for the environment.

    • by dargaud ( 518470 )
      A corollary to this is that the totality of plastics that haven't been burned still exist.
    • by EdoM73 ( 8823461 )
      Recycling cuts off most of the pollution in the production chain, from the drilling spot to the bottle production. It's not that the bottles will walk themselves to the power plant to be burnt.
    • Re: (Score:3, Informative)

      by BigZee ( 769371 )
      If you have really, really good filtering, this might be safe. The problem then becomes the amount of energy and effort to do so properly and the fact that it is a disincentive to building such plants. The reality therefore is that incinerators do have potentially dangerous emissions. The other issue with burning plastics is that we need to stop getting oil out of the ground. Recycling in the way described means that you can create a cycle of usage that reduces and hopefully (one day) would eliminate the ne
      • The other issue with burning plastics is that we need to stop getting oil out of the ground. Recycling in the way described means that you can create a cycle of usage that reduces and hopefully (one day) would eliminate the need for oil.

        We can stop getting oil out of the ground by using nuclear power to synthesize hydrocarbons.

        Plastics are produced from ethane, a hydrocarbon with two carbon atoms. Methane, a hydrocarbon with one carbon atom, is what ends up as natural gas. Any hydrocarbon with three or more carbon atoms ends up as a fuel, grease, wax, tar, or asphalt. Plastics are made from petroleum because it is a cheap way to get ethane. Once we have a cheaper source of ethane then we won't use petroleum for making plastics.

        We burn

    • It's cheap (...)

      I'm not 100% certain, but likely it's only cheaper because we don't charge a reasonable price for the pollution resulting from the production of new plastic. Not factoring in costs carried by the general public makes a lot of things look cheap while they aren't.

      The cost of a metric ton of CO2 emissions is typically assumed to be a bit over $50. More thorough research puts that number at $3000, though (link below).

      However, in general and with the exception of that, you and your chemistry professor are right: if things are cheaper, they probably are also better for the environment.

      https://www.theguardian.com/en... [theguardian.com]

      • One thing the study ignores is you will never have this best case scenario of pure PET. The real issue is sorting of plastic. The typical recycling bin has a half dozen different types of plastic which are extremely difficult to separate.
        • by zmooc ( 33175 )

          That's hardly an issue anymore. Where I live, about half of all plastic waste is recycled and a large part of what we don't recycle is due to people putting it in the wrong bin or plastics that are not recyclable (e.g. aluminium coated plastics). Waste separation technologies have come a *very* long way thanks to AI waste classification. What also helps a lot is education of the public and regulation of the packaging industry.

      • ... it's only cheaper because we don't charge a reasonable price for the pollution resulting from the production of new plastic.

        This looks like a case of "externalities". Specifically, the producer does not usually pay for the disposal of their product as waste. This obviously makes it possible to sell the product more cheaply, so it "pays" to make from new, rather than recycle. What happens next to fix this depends on your view of the purpose of the national economy. Does the economy serve the people, or do the people serve the economy? Assuming that the economy serves the people, some adjustment is required to ensure that produce

    • by azrael29a ( 1349629 ) on Thursday October 07, 2021 @07:10AM (#61868855)
      Sweden already does it. But they recycle about 49% of their trash. 50% is burned, and only 1% ends up on the landfill.
      Source: In Sweden, Trash Heats Homes, Powers Buses and Fuels Taxi Fleets [nytimes.com]
    • I wish I could find the artlcle (it was on a major network in Canada) where a study was done on how much pollution was generated by recycling plastics and other material. Given the need to use trucks to collect it from home and collection points, energy used in recycling centres to sort it (there are many reasons things are rejected for recycling it seems), and then more trucking to some place that will recycle it, and the energy needed in recycling; that in many cases it used more energy and polluted more

    • by MobyDisk ( 75490 ) on Thursday October 07, 2021 @10:03AM (#61869219) Homepage

      I assume your professor was referring to Plasma gasification [wikipedia.org]. While there are plants that do this, they seem wrought with failures. There is one in my home city but it has been problematic for decades. It was bought sold, rebranded, re-sold, etc. I'm not sure if it is running today or not. I think there are still technical challenges to making it practical.

    • The fine article is yet another example to prove my chemistry professor right. We should burn plastics for fuel. It's cheap, easy, and better for the environment.

      Spoken like a true believer in magic. Totally aside from the difficulty of burning it safely - that's presumably a solvable problem, although not necessarily inexpensive - there's the question of "where do we get more?". Do we burn more fossil fuel in the transportation of this plastic than we would replacing what's been burned? I don't think so. I'm pretty sure more energy is required to make plastic than to recycle it.

      We can already see the 'bottom of the well' so to speak when it comes to fossil fuel. Wh

    • Did you chemistry professor also tell you what to do with all the CO2 mixed with other dirty stuff that that results in?
      Is he perchance more of a "0.02% yield + 1.98% concentrated yellow [youtube.com] + 98% tar" type, and less of a Heisenberg purity levels guy?

  • Not competitive with newly manufactured PET.

    Not competitive with recycled PET.

    PET bottles are some of the easiest things to recycle, and some of the most recycled plastics on the planet. New methods for recycling them that are less efficient than currently existing methods are therefore not of high relevance. What is needed is novel methods of recycling dirty and/or mixed plastic trash.

    • What is needed is novel methods of recycling dirty and/or mixed plastic trash.

      Now where was that handy summary...

      Eventually, enzymatic recycling may be able do things that mechanical recycling can't, like recycle clothes or mixed streams of plastics.

      Oh there it is.

      • by Entrope ( 68843 )

        Eventually, this company may put a chicken in every pot and a pony in every garage.
          Because people want ponies. But it's not a good idea to hold one's breath while waiting for that outcome.

      • by Luckyo ( 1726890 )

        Me

        "Eventually it may be able to do it".

        China troll

        "Oh look, it can do it, so you're obviously wrong!"

        • Re: (Score:2, Insightful)

          by Anonymous Coward

          You: this isn't relevant, we need X
          Other person: The summary says they are working on X
          You: some childish trolling and name calling. With a lie about what you said thrown in for good measure...

          Maybe read the summary before declaring something irrelevant. Especially if you are then going to ask them to do what they just said they were doing... It just makes you look silly Luckyo.

    • by AmiMoJo ( 196126 )

      Yeah I guess there is no reason to not just throw it in landfill or burn it if it's not cheaper than the other options *rolls eyes*

      Obviously the case here is environmental. Given the only very small extra cost involved it might make sense to simply require this technology to be used (assuming it can be scaled up and used cheaply without patent encumbrance), much like we required most shops to charge for disposable plastic bags.

      • by Luckyo ( 1726890 )

        For those who sometimes think that far leftists like amimojo actualy give a single fuck about environment, this is an excellent example of how they don't care at all about environment. It's all about building and maintaining personal status. Even online under a pseudonym.

        Because I clearly outlined that PETs are already easily recyclable AND are already some of the most recycled plastics on the planet. It's anti-environmentalist to advocate for less efficient recycling systems.

        And yet this is what is being d

        • by AmiMoJo ( 196126 )

          And yet a lot of PET still ends up in landfill or burned.

          We could re-use a lot of PET without even recycling it. Bottles can be refilled.

          • And yet a lot of PET still ends up in landfill or burned.

            We could re-use a lot of PET without even recycling it. Bottles can be refilled.

            You have to wash them first and check if they're not damaged. This is the reason recycling of glass (!) beer bottles is mostly not done in Poland - it's cheaper to buy new bottles from the glassworks than to collect used bottles from the shops, bring them back to factory, wash them, check them for damages before filling them again.

            • by AmiMoJo ( 196126 )

              The individual can do that themselves. Wash them at home, take them to the shop and refill them.

              • The individual can do that themselves. Wash them at home, take them to the shop and refill them.

                I doubt many customers would want all the hassle of doing that, I would not want to do that myself. It's not feasible for doing large-scale shopping, ie. buying 20 bottles of water/beer/whatever. Also, own bottles don't work well when dealing with carbonated beverages if you want to make sure they are sealed tight.

      • Re:Summary (Score:5, Insightful)

        by Impy the Impiuos Imp ( 442658 ) on Thursday October 07, 2021 @06:02AM (#61868743) Journal

        I recommend landfills for anything mildly hard to recycle. Let robots sort it out in 100 years.

        I predict hot air from activists whining that their local city isn't getting enough money from the bidding process for the right to have robots rip theirs open.

        • Let robots sort it out in 100 years.

          In politics, that is called "kicking the can down the road." It is a way of absolving yourself of responsibilities, because somebody else will deal with the problem in the future. If you take a scale of 100 years, then presumably you think you will be dead by the time the problem gets sorted. How convenient.

    • Indeed. I worked on a pilot in the early 90s to react PET with methanol and distill off the DMTP and EG. It was pretty straightforward and we didn't run into any issues.
    • What is needed is novel methods of recycling dirty and/or mixed plastic trash.

      Clever (bio)chemistry aside, a basic problem seems to be extracting the spent plastic of a particular type from waste. I have no idea what really happens to my rubbish that I may or may not put in the right bins. I know that different plastics don't mix naturally when melted together. I did a plastic welding design, where the prototype failed because one part was polypropylene, and the the other part was polyethylene by mistake. They did not stick. Most people could not tell the difference between polypropy

  • It seems like making bottles a bit more durable and reusing them is much cleaner and economical than recycling or disposal...

    (Standardising packaging would allow different brands to reuse each other's packaging as well, but that can be tricky...)

    Reused bottles will reach end of life at some point though...

    • Aluminium bottles all the way. Not good enough? Alright then, Titanium bottles!

    • It seems like making bottles a bit more durable and reusing them is much cleaner and economical than recycling or disposal...

      I know for a fact that PET bottles can be used multiple times, because I do that for taking water in my work bag every day (or used to before WFH), and the bottles work fine for homebrew beer. But there is no infrastructure for re-using PET bottles. There used to be an efficient infrastructure for re-using glass bottles. You could take your empties to the shop, and get a few pennies back. Same with milk bottles, with leaving your empties (properly cleaned) by the door, for the milkman to pick up. Maybe I am

      • by MoHaG ( 1002926 )

        Here sone of the Coca Cola bottlers now have returnable plastic bottles [businessinsider.co.za]. (The 2l ones are new. Some of the 1l and 1.25l glass returnables were replaces with thicker plastic ones). It is the exception though and the vast majority of drink bottles can't be returned.

        I'm not aware of any programs to reuse packaging for anything outside beverages either - shampoo, yogurt, condiments, etc...

  • This goes into the costs of breaking down the plastic into its constituent components, and then creating new plastic from it...
    But what's wrong with taking existing plastic that is already formed into usable shapes (ie bottles) and then simply cleaning and reusing them as bottles? Surely that must be even cheaper and more energy efficient.

    • I doubt their lawyers and insurers would let them, as used bottles could be weakened and not survive issues with pressurization or dropping.

      • We used to have reusable/returnable plastic bottles in the 1990s. Then it fell out of fashion, out of convenience - not because the bottles didn't work. With suitable legislation, maybe there could be a comeback of this. Just Pigou the shit out of wasteful behavior.
    • Loop is making an attempt at this:
      https://loopstore.com/how-it-w... [loopstore.com]

      But their selection of products is VERY limited right now.

    • The bottles currently in use are pretty thin, and thus not all that durable. You'd probably only get one or two more cycles out of each one.

      They could be made thicker and more durable. But they currently aren't.

      Also, while this particular plant is only doing bottles at this time, the idea is to expand the capabilities to non-bottle things that are currently impossible to recycle, like clothes.

    • then simply cleaning and reusing them as bottles

      That would be vastly more efficient than rendering the bottles into raw material, then making from (recycled) new. This is the argument behind re-usable plastic carrier bags from supermarkets. In the UK (and other countries I presume), the move to charging for carrier bags, and providing more durable bags for multiple use, led to an enormous reduction is plastic waste. I have to say that my two usual robust carrier bags are showing their age, and I should replace them, but they are over two years old, so i

  • PET chemical recycling is littered with companies that have tried this and either not been able to make the chemistry or economics work. Most recently in the news with this is Loop Industries. They skipped the hard part of working out the chemistry and were just a straight-up scam.

  • PET is already the single most recycled plastic, and as the article states, the new method is twice as expensive as virgin PET, while existing methods are only 50% more expensive.

    Talking about recycling PET is like talking about how you plan on making jewelry out of gem quality diamonds.

    You want to impress people, figure out how to do it to LDPE, Polypropylene or polystyrene.

  • Scientists say they may be able to synthesize a completely clean biofuel using the enzymes in finely shredded fungi, such as mushrooms...
    Some critics have questioned the ethics of the process, but admit they are comforted by the researchers’ strong Morel fibre.

    If I were an enzyme, I'd be DNA helicase...
    So I could unzip your genes

  • Still good that it can be reprocessed, or course, but this sounds closer to rotting it down to its base chemicals, to then use those.

    • this sounds closer to rotting it down to its base chemicals

      That might be preferable to just letting the plastic lie in the ground for centuries, building up year after year. And you are lucky if the stuff stays buried for centuries, because a hell of a lot seems to have got into the oceans, and is steadily poisoning the wildlife.

  • It is really surprising humanns managed to beat microbial evolution at this problem. Eating plastics would be a great benefit for microbes.

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