Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Newly discovered deep-sea enzyme breaks down PET plastic

phys.org

Post reply on HN
Print view View original

51–60 of 78 posts

Re: Newly discovered deep-sea enzyme breaks down PET plastic

#51

Post by gilleain »

testfoobar wrote: post #34
gilleain wrote: post #3

Slightly misleading headline, as PET (polyethylene terephthalate) hydrolases were already known - see https://www.chm.bris.ac.uk/motm/PETase/PETaseh.htm This is a study of an archaeal enzyme (from the deep-sea) that can degrade both long-chain and short-chain polymers that is more efficient at 70 deg C than other enzymes. The details are that this is a feruloyl esterase with a conserved alpha/beta-hydrolase fold but…

"this is a feruloyl esterase with a conserved alpha/beta-hydrolase fold but with an additional flexible 'lid' domain that covers the active site" As educated as I think I am, it is always humbling to read a hacker news comment that I cannot understand. ELI5?

Apologies, that was meant for the specialists :) It is mostly just technical jargon so do not feel too humble ...

So I'll break it down:

- "feruloyl esterase" : an 'esterase' is an enzyme that makes or breaks ester bonds. In this case, 'feruloyl' which I've never heard of but apparently is some small molecule that is normally attached to a sugar. https://en.wikipedia.org/wiki/Feruloyl_esterase

- "conserved alpha/beta-hydrolase fold" : a structural pattern (fold) that is shared (conserved) between a set of structures. In other words, these enzymes all have roughly the same shape. https://www.cathdb.info/version/v4_3_0/superfamily/3.40.50.1...

- "additional flexible 'lid' domain that covers the active site" : a 'domain' is just a compact part of a protein, without going into too much detail. They are calling it a 'flexible lid' as the idea is that it moves out of the way to bind the substrate to the active site (where the reaction is carried out) and back again when fully bound.

Re: Newly discovered deep-sea enzyme breaks down PET plastic

#52

Post by justaskme »

gilleain wrote: post #18
pneumic wrote: post #8

Earlier quoted context omitted.

Yeah, it's not bad news at all but it appears to be one of many that still require considerable heat, industrial infra, etc. Has anyone attempted to put these enzymes to the test in at some scale in an industrial setting, I wonder?

No idea. From skimming some university press releases, I see a lot of "potential for!" and similar wording. This https://news.utexas.edu/2022/04/27/plastic-eating-enzyme-cou... has "Up next, the team plans to work on scaling up enzyme production to prepare for industrial and environmental application. " which is more promising. As far as I understand, yes it is a very different challenge to make a bioreactor for actu…

Feels like it's always "potential for"... sigh

Re: Newly discovered deep-sea enzyme breaks down PET plastic

#54

Post by morsch »

dzdt wrote: post #47

The way to understand the origin of fossil fuel deposits is that hundreds of millions of years ago trees were made of plastic. Thats not quite literally true but it gives the right sense. In the Carboniferous period trees grew abundently but there were not yet bacteria that could break down the lignins composing the woody structure. Its very similar to what you'd get with plastic trees today: they would fall and pile…

When I searched for this, I found there to be some debate on it (isn't there always?): https://www.pnas.org/doi/10.1073/pnas.1517943113 https://arstechnica.com/science/2016/01/why-was-most-of-the-...

Re: Newly discovered deep-sea enzyme breaks down PET plastic

#55

Post by Intralexical »

kwhitefoot wrote: post #33

Why do we want to break down PET? Why not just re-use it?

Heat, stress, and light will probably break it down mechanically over time no matter how diligent you are about reusing or recycling it.

At the very least, this should hopefully mean that all those scary endocrine-disrupting and bioaccumulating microplastic and nanoplastic particles that are apparently being shed by the millions every time you heat or handle anything plastic aren't necessarily going to keep building up forever.

Re: Newly discovered deep-sea enzyme breaks down PET plastic

#56

Post by Intralexical »

digging wrote: post #38
monocasa wrote: post #9

Earlier quoted context omitted.

Less fun, PET is heavily used in medical devices including implants. There's a huge cut to life expectancy if it becomes a secondary food source for something like an engineered MSRA strain.

More reason to be furious at plastic peddling billionaires. They made us hostages. We still have to stop them, but it's going to hurt even more.

Eh. Thinking plastic would last forever was probably a reasonable assumption at the time. I doubt it was the billionaires making that design call. Though in hindsight maybe we should have known better, given the history of lignin and natural waxes.

Though especially given the history of lignin, we probably have millions of years before medical devices being eaten by microbes becomes a widespread problem that anyone seriously needs to worry about. There's bigger fish to fry right now.

Re: Newly discovered deep-sea enzyme breaks down PET plastic

#57

Post by neftaly »

testfoobar wrote: post #34
gilleain wrote: post #3

Slightly misleading headline, as PET (polyethylene terephthalate) hydrolases were already known - see https://www.chm.bris.ac.uk/motm/PETase/PETaseh.htm This is a study of an archaeal enzyme (from the deep-sea) that can degrade both long-chain and short-chain polymers that is more efficient at 70 deg C than other enzymes. The details are that this is a feruloyl esterase with a conserved alpha/beta-hydrolase fold but…

"this is a feruloyl esterase with a conserved alpha/beta-hydrolase fold but with an additional flexible 'lid' domain that covers the active site" As educated as I think I am, it is always humbling to read a hacker news comment that I cannot understand. ELI5?

Enzymes are kind of like a tool for breaking apart lego blocks, or a jig for assembling them. This sounds like a moving part that covers the "teeth" and makes it more effective (or less likely to get jammed by the wrong molecules?).

Re: Newly discovered deep-sea enzyme breaks down PET plastic

#58

Post by eindiran »

pneumic wrote: post #8
gilleain wrote: post #3

Slightly misleading headline, as PET (polyethylene terephthalate) hydrolases were already known - see https://www.chm.bris.ac.uk/motm/PETase/PETaseh.htm This is a study of an archaeal enzyme (from the deep-sea) that can degrade both long-chain and short-chain polymers that is more efficient at 70 deg C than other enzymes. The details are that this is a feruloyl esterase with a conserved alpha/beta-hydrolase fold but…

Yeah, it's not bad news at all but it appears to be one of many that still require considerable heat, industrial infra, etc. Has anyone attempted to put these enzymes to the test in at some scale in an industrial setting, I wonder?

I was recently at a party and spent some time talking with someone who has a stealth startup working on this exact problem. He said that they aren't the first, but getting the scale right (in an industrial setting) and finances right enough that someone is willing to spend the money to set it up is far harder than just finding an enzyme that can break down PET / similar polymers.

Re: Newly discovered deep-sea enzyme breaks down PET plastic

#59

Post by geoelectric »

Max-q wrote: post #30

As much plastic as we dump into nature now, we increase the chance for a mutation of a microbe being able to digest it. If that microbe manage to multiply and spread, plastic can start to rot, just like wood is doing now. On a long term basis, that might be a good thing, but in the short term it would be a catastrophy. We are using plastic as a long lasting material, often with no surface treatment. Imagine if wire i…

IIRC, “plastic eater” was one of the mutations of The Andromeda Strain in the eponymous Crichton novel.

Re: Newly discovered deep-sea enzyme breaks down PET plastic

#60

Post by ars »

digging wrote: post #39
hanniabu wrote: post #15

Earlier quoted context omitted.

It would increase consumerism since everything would need to be replaced on a periodic basis

Everything? I think instead, we'll just stop making most things out of plastics. We have longer-lasting, more durable materials than plastics already, for when you want something that will actually survive decades or generations. They're metals and woods and stones. Some things, like wire coatings, will still likely need to be plastic and will become disposable. But most uses of plastic for long-lasting goods will ju…

Woods? If wood can survive so can plastic in this hypothetical world. Just keep water away from the plastic.
Post reply on HN