The problem with enzymes eating plastic is that enzymes are small Pacman-shaped protein blobs that are maybe 10 nanometers in diameter, whereas things made of plastic like bottles or even microplastics are huge in comparison. How do you get the little Pacman jaws around the bottle to start breaking it down?
The research paper [1] describes the authors’ effective innovation. They make a protein where one end is a pore-forming shape, and the other end is a PET cutting (called a PETase in the jargon of the field). This way, their protein can access nooks and crannies in the macroplastic shapes, allowing tons of copies of this small enzyme to fully degrade a bottle.
Without this, a great deal of physical agitation is required to break down the plastics into small enough chunks that earlier Pacman enzymes could work on, increasing the time and the cost.
I hope we’ll see the idea of linking the enzymatic “scissors” to a protein pore be used to engineer enzymes to degrade other types of plastics in the future, as the general idea of getting the catalytic machinery into physical contact with every bit of the bottle is broadly applicable to all plastics, not just PET (which is great news)
1. https://phys.org/news/2023-10-scientists-artificial-protein-...
To get an idea I asked wolfram alpha what is the volume of the average human, and apparently that is around 66 liters. Then I looked up the estimated water volume of the Baltic sea, and wikipedia says it is 21,700 km^3 of water, soo
$ units
586 units, 56 prefixes
You have: 21.7E3 km3
You want: 66 liters
* 3.2878788e+14
/ 3.0414747e-15
Unfortunately, that makes your comment a bit confusing, since the context of the title change is not present. I think the best solution would have been the title, "Scientists create artificial protein capable of degrading [PET] microplastics in bottles".
It was never about precision, truth, nor actual science. It was always about "plastics=bad" ideological virtue signaling, just like "chemicals=bad" and "(non-ionising) radiation=bad" before it.
Microplastics were not a concept created for ideological virtue signaling. I don't know who manipulated you into thinking that was true, but you may wish to re-evaluate where you've been getting your information. The good news is that you don't have to depend on some invented sinister backstory for microplastics, you can instead read the paper where the phrase was coined for yourself (https://www.researchgate.net/publication/8575062_Lost_at_Sea...) and see that it was just a lot of typical boring science like searching through sediment and plankton samples, and keeping track of what lugworms eat. A paper that concludes with "we'd need more research to determine if there are any environmental consequences" is about as far from ideological virtue signaling as it gets. Take your own advice and "Beware those who distort the truth and exploit fear for their own gains."
As far as precision goes, currently microplastics are for plastic bits smaller than 5mm. We even have primary and secondary categories for them. Nanoplastics are for bits smaller than 100 nm. Do we really need a better classification system at this stage? I imagine that shortly after we do, we'll get one. Science loves to come up with boxes to put things in.
---
Why are we still not talking about plasma gasification? https://en.wikipedia.org/wiki/Plasma_gasification
As far as I can tell, the only real "disadvantages" if you can call them that, are:
1. more expensive than throwing the garbage in a big pile somewhere
2. need to clean it from time to time
3. not necessarily a profitable business
Other than that, it can handle just about anything that's not radioactive, can be designed to produce 0 toxic byproducts, and can run at or at least only slightly below energy neutral. Plasma gasifiers can also consume a huge amount of garbage for their size, so much so that the US Navy is starting to put them on the latest generation of aircraft carriers.
Not building out more gasifiers seems to me a failure of the free market. Because it's hard to make it profitable, no one is doing it - when really we should just be building one or two near every major city and funneling all our garbage there.
In theory, we could build out enough to start working through all the landfills too.
That was my understanding the last time I worked on this. I would love to hear about any progress on this.
For what it’s worth, I think the companies that have tried this have not pursued the correct business model. They all either want to sell their system (bad idea) or sell syngas (ok, but not enough). What they need to do is charge tipping fees like a landfill to simply dispose of the trash.
This would also bring you the added benefit of actually knowing that your waste does not contribute to introducing harmful toxins to groundwater supply or even the sea.
Usually the issue with waste-to-energy is locating a facility, and I would imagine plasma gasification would run into similar NIMBY issues just because people don't like the idea of being next to a large intake facility of garbage, regardless of how bad it is in practice.
> degrading PET [particles] and reducing them to their essential components, which would allow them to be broken down or recycled
> "One variant breaks down the PET particles more thoroughly, so it could be used for degradation in sewage treatment plants. The other gives rise to the initial components needed for recycling. In this way we can purify or recycle, depending on the needs," explains Laura Fernández López
Hmm, so that sounds like it's a step forwards (working the problem), but not yet a solution that can recycle PET into something anyone can use
Edit: this is why I'm asking...
Article: "... the bacterium Idionella sakaiensis, which is capable of degrading this type of plastic and was discovered in 2016 in a packaging recycling plant in Japan."
Wikipedia on Ideonella sakaiensis: "[they] mineralize 75% of the degraded PET into carbon dioxide" (to be fair, it also produces a "MHETase enzyme" which "could also be optimized and used in recycling or bioremediation applications") https://en.wikipedia.org/wiki/Ideonella_sakaiensis
* This protein acts as a PETase - see also <https://news.ycombinator.com/item?id=37659327> - but may work at room temperature, and more efficiently
* The term 'artificial protein' is a bit awkward - it's a modified version of an existing protein from an anemone (see : <https://www.rcsb.org/structure/4tsy>)
* The scaffold protein is a pore-forming structure - where multiple trans-membrane helices come together, like melittin in bee venom - so they claim it could work as part of a membrane-bound complex
I agree. The proper term would be engineered protein, since it is a fusion of two existing protein domains: an already engineered cutinase (a PETase ancestor) with a pore-forming protein (FraC).
Plastic and Microplastics are an environmental hazard to animal life, with a specific threat to aquatic life. The plastic itself is a significant physical hazard for the life. The attached link has an incredible photo of a the scale of a small fish and various microplastics. It's important to note that currently there is no cost effective way for water treatment plants to filter for these.
https://education.nationalgeographic.org/resource/microplast...
Scientists are still unsure whether consumed microplastics are harmful to human or animal health
Because plastics are inert. Beware those who distort the truth and exploit fear for their own gains.
There’s no need to destroy our perfect status quo
https://www.warwickri.gov/sanitation-recycling/faq/why-cant-...
Many cities have banned recycling the most commonly used plastics, like plastic water bottles made of 1 (PET). Where I live, 1 and 2 get recycled, 3 (PVC) gets thrown in a landfill and 4-7 get sent to a separate refinery which converts them to diesel fuel.
Not to mention that there seems to be no standard on the legibility of the number.
How many people reading this have thought about automating recycling by having machine learning sort the types? Yet I've never seen "recycling engineer" as a job title. Nor have I seen any grants for improving recycling. Nor any corporations/billionaires making recycling a priority. There have even been TV shows by prominent celebrities pushing propaganda against recycling, like the Penn & Teller: Bullsh*t! episode from the post Dot Bomb luddite era of 2004:
https://www.imdb.com/title/tt0771119/
We're willing to drink a protein that can degrade plastic before we're willing to hold industry accountable for the waste it produces?
It's window-dressing so the industry can shift attention away from limiting production of something that shouldn't see anywhere near the widespread use it does.
The same is true of the stories you see all the time about some group or person doing a beach cleanup. It casts the problem as the fault of people dumping the stuff, while pretending like it's a solvable problem, if only we had enough people rummaging around cleaning up beaches, parks, ocean bays, fields, hiking trails, abandoned properties, etc.
the broader point is valid that recycling even hdpe is difficult because of the diversity of fillers and other additives, not to mention variation in molecular weight even before scission by ultraviolet, hydrolysis, or the heat of the molding process
there are in fact people who make a living by recycling. until recently around here they even bought pet, offering lower prices for the colored pet (because with pet you really can economically separate out the fillers and additives and repolymerize it to a known molecular weight)
mostly they recycle paper (mostly cardboard), copper, bronze, brass, lead, and aluminum. glass, steel, concrete, and plastics can be recycled but it's hard to make it profitable
if you hold industry liable for damage done by people improperly discarding its products, soon you will have no industry
If it's predominantly being misused, then they do have a moral obligation. They control the packaging, and they know how much of it will end up improperly discarded. And by moral obligation, I really mean it should be a regulation to capture the damage done. Perhaps the recycling deposit from aluminum cans should be expanded.
I don't see how this follows. It might make plastics more expensive... but that's not necessarily a bad thing.
Reminded me of Ice-9Quibble: "microplastics in bottles" looks far more like keyword stuffing then a sensible description.
And if you're familiar enough to know what plastic types exist, you probably also realize that this won't be a miracle protein that can tackle a ton of different chemicals with this one innovation/advancement.
Unless you're a chemical engineer, I can't think of a place where anyone would need to know what PET is. Bottle returns don't have different holes based on the recycling type, I can even throw glass and cans in with plastic bottles and it'll scan the label and sort it out. For me, I might have made a tentative guess that PET is used in bottles, and my dad inspects factories that produce that stuff and so it's not like I had no exposure to it (just no interest in the myriad of plastics we're trying to avoid)
PLA is usually the go-to; it's ideal in nearly every respect except cost, especially its modern formulations. But PETG is still often used for its heat resistance, Polycarbonate is great for physical strength, ASA is lovely for outdoors work, ABS is still the cheapest option... and some people are crazy enough to print Nylon.
The negative known effects of microplastics are emerging. The public are not as aware of the extent to which they are exposed to microplastics daily. We don't actually know the full extent of the damage being done yet, but what we do know so far is that microplastics affect neurological development, fertility, and are known endocrine-disrupters. It will take time to see the full effects of microplastics in our environment, and it's going to get worse before it gets better.
Why do we allow fueling our energy plants and automobiles with fossil fuels that causes air pollution responsible for 1/5 deaths world wide? [0]
Why do we allow one-time use plastics and synthetic tire rubbers while knowing it causes irreversible microplastics pollution of land and sea?
... looking at you, fossil fuel lobbyists.
[0]: https://www.hsph.harvard.edu/c-change/news/fossil-fuel-air-p...
Fossil fuels are hydrocarbons - they're made up of carbon and hydrogen (and very little oxygen). https://en.wikipedia.org/wiki/Hydrocarbon
Carbohydrate is C + H + oxygen, and generally refers to biological molecules derived from glucose. https://en.wikipedia.org/wiki/Carbohydrate
https://blogs.scientificamerican.com/observations/climate-ch...
Microplastics are an ugly witness to pollution, but are likely not themselves very harmful.
Other plastics can be directly toxic, such as styrenes.
A viable general replacement for plastic needs to beat plastic on price, weight, durability, sanitation, strength, and so much more.
Also, how much plastic has been produced over the last 100 years? It also would have been nice not to have just thrown it all into a landfill, but now that it's there do we really want to release all the CO2 that's been safely locked away underground in solid plastic?
They certainly have a lot of inherent utility, but given the emerging risks to the planet's ecology and our own health, I think it's hard to see a future where we extensively use plastics to the same extent we do now.
I don't claim to know what's best out of recycle, incinerate, landfill and biodegrade. To me none of them seems obviously bad. Various calculations would need to be done.
It's probably significantly better than pretending to recycle the stuff and then burning fuel to ship it somewhere else.
This applies for everything about batteries, and environmental techs.
The supraconductor crystal news was also quite a revealing event of the problem.