I'm torn as to which poster in this particular thread to respond to in order to ask a follow up question.

First.. thank you (all the people providing useful information here) for breaking the normal Slashdot mold and being so informative.

You are welcome.

I'm not able to read the paper as I believe it's several degrees above my level of chemistry and materials.

When I read these "too good to be true" articles, my initial knee jerk reaction is to wonder "what's the catch?". And the first thing that comes to mind is that while it's possible to have perfectly balanced chemical reactions so that whatever you put in generates a perfect amount of several desired compounds.

Well, in a paper every chemist will write an well balanced chemical equation, as a simplified model of what will happen when you put together two or more reagents that can interact with each other.

After creating your ideal reaction on paper, the next step is to put your glassware to work and build a small laboratory scale reactor so you could analyze the variables and also to be able to successfully recreate the previously theorized reaction in your lab, obtain the product, purify and subsequently analyze it. You can also control, adapt or change a lot of variables like temperature, pressure, pH and so on.

After concluding that your chemical reaction (in this case, a biochemical reaction) is promising and you believe that you can advance your process to a semi-industrial (or even industrial) scale, you should start seek for partnerships, financing and so on.

Once approved and financed your semi-industrial (or industrial) biochemical process will involve a lot of other professionals to become a reality. Also, all the simplified variables (in number and in complexity) you previously had in your laboratory scale model will increase significantly.

There is also a lot of new problems emerging in a new and very complex scenario. To present more concret examples of these problems and variables lets use the topic in discussion. If you want to create an industrial scale for degrading PET using enzymes you will need to add some previous steps to your process as a whole, like sorting, cleaning and grinding all PET found in the trash, so they could be used in the next steps.

It is necessary to put in mind that it will be very difficult (otherwise impossible) to guarantee that all PET previously processed will be 100% free of dirt and other contaminants (like other kind of plastics, or even non-recyclable trash). Variables like temperature, pressure, pH, liquid medium and so on will be considered a more complex task.

To end with a few examples, it is also important to remember that your enzyme is not immortal. You will need to constantly replace it in the reactor(s) you planned in this new industrial scale entrepreneurship. You will also need to be concerned about the constant production of new batches of enzymes for use in your reactor(s).

Your product will also need to be extracted and purified if you want to utilize it for other purposes. Just to point out a few things about this matter.

But what I'm wondering is... what comes out of this chemical reaction?

This (bio)chemical reaction converts Poly(ethylene terephthalate) in terephthalate (or terephthalic acid, depending on pH) and ethylene glycol, using an specific enzyme as a catalyst:

PET -- Enzyme ---> Terephthalate + Ethylene Glycol

I know that not all plastic bottles are the same. I believe they're fundamentally close, but on the scale they're talking about which is hundreds of tons of input... what's coming out... even in trace amounts? Is the result scary?

There are a lot of different kind of polymers in the market and the most used ones are listed in this site. Attention to the symbol composed by three arrows forming a triangle with a number inside and and acronym below. It will show to you what kind of plastic the bottle you are holding is made of.

What about the enzyme itself? What's the cost (environmental) of producing the enzyme.

Before knowing the producing cost you need to understand how to mass produce a target enzyme for your industrial application. Here is the basics:

In the modern day we can produce enzymes using bacteria. First, you need to try to find a (safe) bacteria that can produce your enzyme. If this is not a possible task you will need to insert a gene encoding the enzyme into a bacteria so that this microorganism can produce it for you. The best scenario is to have a bacteria that can produce and export (outside its own cell) the enzyme for you, so you can retrieve your product from the medium and isolate it (and preserve it) for later use.

Also, you need to estimate how much enzymes you need for continuous use (i. e.: you will need to continuously feed your reactors later so you need to calculate a lot of information to create a workable enzyme production reactor(s) and an enzymatic degradable PET alike, the size, the time, the feed back, the many points analyzes, the real time tests per se, the side ways, the flux control and so on.

Now that you can have a grasp of the situation I can assure you that it will be a very expensive entrepreneurship.

And finally, about the environmental costs, you need to sum up every variable in your industrial scale biochemical process like, water and electricity usage, the residues and sewage water generated in the process, the pollutants that your industry can generate to the atmosphere and so on. Everything depends on how you proceed, how you build, how you maintain it. But, again, it will be a lot of money.

I can't imagine that production of an enzyme like this is entirely without a footprint.

When you mean a footprint are you talking about the industrial project as a whole? From the initial idea to the industrial production? If so, there is a draft about this matter in the previous answers.

And so far as I know, the recycling plant around the corner from where I live employs a whole team of chemists to analyze piles of garbage and decide what chemicals to mix the garbage with to neutralize the smoke coming out of the stacks when it's being burned.

Will the biproducts of this process leave highly toxic materials behind that will be far worse to neutralize compared to simply burning the PET to begin with?

I think that the idea to hire chemists to take care of this process is to ensure that this post operation as a whole will be ecologically correct. They need to make sure that all the waste treatment will proceed without leaving nothing that could contaminate the soil and/or the atmosphere later. If they are a serious company they will do the right thing.

Thanks so much in advance if you happen to find time to answer some of these for me!

I' m glad if I could help.

Recycling can help, but the problem isn't lack of recyclability. Plastics are made from oil, and we get oil from underground. So simply burying plastic in landfills creates a zero net impact on the environment.

The process of burying plastics can only lead to create an impermeable layer underground, that will block the rain water from being filtered and safely return to the groundwater in its natural renewable cycle. This can cause a lot of environmental problems.

On the contrary, if you have to create a safe landfill, you need to make sure the ground is sealed (impermeability) from leaking to below ground, otherwise all the pollutants and contaminants that can permeate the soil will reach the groundwater contaminating it. With a god sealed ground you will make sure that all the trash put in there will stay safe and/or be naturally degraded without contaminate the soil.

But the problem is people who litter - they don't throw plastics away in the trash when they're done using them. They throw it away on the ground, in rivers, and in the ocean. Recycling doesn't help with that, as someone who is unwilling to throw away plastic in a trash can, will be just as unwilling to throw away plastic in a recycling bin.

But the best solution is not to create landfill regions, but a good non-centralized and modular recyclable system in the whole country (in all countries), to make sure that all trash will have a safe destination. And these global systems starts with how industries creates their own packages for their products, how people separate and organize its own generated trash, and so on.

The only way this new enzyme can help is by increasing the profitability for recycling plastic. Recyclers can then offer cash for people turning in plastic trash, thus making it more likely that people will recycle plastics instead of littering.

This enzyme only works for some plastics but not for all kind of plastics we can naturally find in everyone's trash. So the profitability will be partial. They need to separate all kind of plastics to select only the ones that can be degradable by this specific enzyme. To increase the profit for this process, (1) people need to help separating each kind of plastic from their own trash and, (2) the country (or State, or City) system responsible for collecting all the separated recyclable trashes people generate all day, needs to ensure that all of them will reach their own destinations correctly.

I think some way to try to explain this matter is: Every kind of enzyme are used to be very specific in what they can "cut", e. g..: some specific chemical bond. So this enzyme will be able to degrade some kind of plastics because they have this specific region for docking (and subsequent cleavage), but with other kind of polymers this enzyme will be able to do nothing.

I suppose they are probably referring to some polymer nano-particles used in a polymerization process. But in this case in the reverse order because the polymer is being decomposed by the enzyme, generating a lot of nano-fragments.

Just adding some extra info to your previous comment, because Slashdot summary states that the enzyme doesn't work on polyethylene alone:

The enzyme can't recycle other major types of plastics, such as polyethylene and polystyrene, which have bonds between building blocks that are harder to break.

and apparently Google doesn't help people easily understand the difference between Polyethylene (PE) and Poly(Ethylene Terephthalate). So, I found in some very old book of mine some good info:

Polyethylene (PE)

Polyethylene is the most widely used of plastic in the world, inclusive several copolymers of ethylene in addition to their homopolymer (the first synthesis of polyethylene was from diazomethane, but its commercial preparation in the 1990s was via the polymerization of the ethylene monomer). The polyethylene homopolymer has the simplest chemical structure of any polymer:

The commercially available resins, however, have far more complicated structures with branched chains and semicrystalline morphologies not indicated in this simple representation. Depending on their copolymer composition and the polymerization process used, commercial polyethylenes display a wide range of average molecular weights, molecular weight distributions (polydispersity), and chain branching in the resin. These molecular parameters affect the ability of the macromolecules to pack closely into a dense matrix and also control the extent of crystallinity in the material. Because of their semicrystalline nature, polyethylenes do not display their theoretical density of 1.00 g/cm3 (or the theoretically expected melting point of about 135oC) but show a surprisingly wide range of physical properties. Based on these, particularly the bulk density, the resins are divided into three basic types:

• - Low-density polyethylenes (LDPE)
• - High-density polyethylenes (HDPE)
• - Linear low-density polyethylene (LLDPE)

Poly(ethylene Terephthalate) or PET

Poly(ethylene terephthalate) is the condensation polymer made from terephthalic acid and ethylene glycol (diester, at 270-285oC). The acid or its dimethyl ester is obtained by the oxidation of p-xylene, a product from catalytic reforming naphtha. The glycol is obtained from ethane via corresponding cyclic oxide. With the availability of purified terephthalic acid since the 1960s direct esterification of the acid in a continuous process is used in commercial production of the polyester:

In resume, both are two different chemical structures and the enzyme only works with PET and not PE.

Font: Andrady, Anthony L., Plastics and the Environment, 2003, pp. 83, 104, ISBN 0-471-09520-6

The issues are twofold.

COBOL programmers with credentials to back it up either (a) already have a VERY high paying job in the financial industry or (b) have retired.

Well, my previous comment had a little funny in between...

...But, as a possible scenario, this is still not too much outside from reality if people try harder. All novices could try to learn COBOL the hard way: l really believe in learning on the job. If they could join forces with other ancient COBOL programmers (inclusive the retired ones) they could intake a lot of knowledge (and code) in the process. Including, many COBOL programmers probably have easy access to personal data with good code (and possibly old machines running with it) to help the novices to learn the language faster.

And as I state before, I believe there will be a lot of legacy systems running COBOL for at least a decade from now on. In the hard way of learning I suggested earlier I believe they will have enough time to be part of the COBOL main front in no time. But I also believe this is a task for a very few people. The process is a very narrow funnel.

These States want volunteers that will work for free, rather than pay the market rate for one.

This is the worst part of the process but I think it is happening only now, because of the pandemic. And I really believe that these States are trying to take advantage of people in this kind of situation, because I really believe that money is not an issue.

And this problem will not involve the novices because they will not be able to help anyway (but they could learn a lot if they were able to be together with the specialists during these missions). But outside this crisis COBOL will always be a very well paid market for the experts in this programming language.

I believe that, if you always want to start to learn COBOL but never have the chance (or was too much afraid of) to start your studies in some very very ancient language, you don't need to worry anymore! You still have a lot of time to catch up with the other dinosaurs and earn some very good money. I think there will be a lot of legacy systems drowned in COBOL still lurking around for at least one or two more decades from now on... :D

Instead of an another descentralized better solution to take place, you are suggesting a centralized, absurdly expensive and (incredible) dangerous one, instead?

.

Solar power satellites' technology is:

• centralized: because, doesn't matter how many of them you put in space, you will need to focus all that energy in just one single point on Earth so you could try to minimize the already higher threat it can becomes to us if misused or just because of some malfunction.
• expensive: Satellites are just an absurdly expensive way (resources, production, launch, constant control, constant protection and periodic maintenance) to obtain solar energy to be used, here down on Earth.
• dangerous: the problem just increases as the need for more energy rises. All that energy constantly collected from the sun needs to be beaming down to Earth in somewhere, and I think everyone can imagine what some malfunction or even an terrorist attack to the satellites in space can do against us on land. And I am not talking about the obvious natural threat within space (meteorites, space junk, solar radiation burst and so on).
• monopoly: terrestrial solar technology (including solar panels, batteries, and all the related electrical hardware in between) is already an expensive one to the whole world, where not all the countries have the budget (being a government or just private companies) or even the best technology to produce it in a decentralized large scale way. And with satellites, things becomes even worse. Just a few countries can produce satellites, and if you are counting the ones with the capability to launch this satellites, it is even fewer. If this technology becomes the energy "solution" in the future for the whole world, it will be in the hands of a few... that will be able to control the entire world. I think you can imagine the chaos, or worse, the total human enslavement process it will become in the future.

Give me a house, and I'll volunteer to keep the neighbourhood small-scale nuclear reactor in my sub-basement. I can keep my irradiated survival food in my basement just above.

At least you will be able to claim that all the food stored in your basement is 100% free of germs (or perhaps, that it will contains a large number of microscopic mutated threats) :D

You want to do the right thing? Just become a vegetarian ;)

the moon acts as a physical shield that isolates the lunar-surface telescope from radio interferences/noises from Earth-based sources, ionosphere, Earth-orbiting satellites, and sun's radio-noise during the lunar night.

This is not the only thing the Moon is good at shielding...

Lets hope they choose a crater with minimum probability of being constantly hit by meteorites, because the Moon were always a good target for this kind of "rain".

So, what are they trying to create: The Blob, The Raft, The Stuff or maybe some Phantoms? :(