Plastic waste eaten by enzymes ⏲️ 6 Minute English

Hello. This is 6 Minute

English from BBC Learning English.

I'm Neil, and I'm Beth. Plastic pollution is a problem

we've discussed before on 6 Minute

English. It's an environmental issue which,

like the growing amounts of plastic waste, isn't going away.

And now microparticles of plastic have even been found.

Can you guess where Beth? Um,

Let me guess. In our food? Inside dead animals? At the North Pole?

At the top of Mount Everest,

although the other places

you mentioned are true as well.

Plastic is a tough problem to fix.

But fortunately, scientists may now have found a solution.

In this programme, we'll be hearing about chemical recycling

a ground-breaking way of making old plastic new again.

And as usual, we'll be learning some useful new vocabulary as well.

But first,

I have a question for you, Beth. Visit the country or seaside

and you'll soon see evidence of plastic waste.

According to the UN,

around four hundred million tons of new plastic is produced every year,

Much of it going to waste. It is hard to imagine

what 400 million tonnes

looks like so

which of the following,

if you placed on a set of scales, would weigh about the same.

Is it, a) all the people on earth b) all the cars or on earth, or c)

all the elephants on earth?

I think all the cars on earth would weigh about 400 million tonnes.

OK, Beth. We'll find out if that is the right answer later.

Globally, less than ten percent of all plastic gets recycled.

Some gets incinerated or burnt and

about half of all plastic waste goes straight to landfill,

meaning it's buried underground.

But as reporter for BBC

World Service Programme,

'People Fixing the World',

William Kremer explained, this only fixes part of the problem.

So, there is a mechanical process where some plastics can be sort of melted down

and remoulded into a new shape or a new form,

but not all plastics can go through that process at all.

And also it loses a little bit of quality

every time you do that.

So it will become slightly more brittle.

So, it's actually more downcycling than recycling -

every time it goes through that process

it gets less useful. Each time

plastic is recycled, it gets more brittle, meaning

it's easier to break or crack. As a result,

what we call recycling is actually downcycling,

creating recycled products which are less valuable

and of lower quality than the original waste product.

And that's where the new discovery fits in. Chemical recycling

uses enzymes, natural chemicals which cause changes in other chemicals

without being changed themselves.

Certain enzymes have evolved the ability to break down plastic

into its basic building blocks, and use that to make new plastic.

The problem is that very few enzymes exist,

which can break the chemical bonds in stronger plastics.

Like PET,

the plastic used in drinks bottles. At least,

that's what scientists used to think, until researcher,

Sintawee Sulaiman took a autumn walk in the park near her laboratory

at the University of Osaka, Japan. In a pile of rotting leaves,

she discovered the microorganism 'leaf-branch compost cutinase',

or LCC for short. Sintawee mixed LCC with plastic

and left it in her lab overnight.

She was surprised to return the next morning

and find the plastic gone, eaten by the enzyme.

The news spread and soon,

scientists were predicting a major breakthrough,

as William Kremer reported for BBC

World Service Programme,

'People Fixing the World'. This discovery wasn't the end

of the story, but the beginning.

LCC showed promise in breaking down

PET plastic, but it needed a lot more work to become stable and effective.

The LCC enzyme showed promise

in breaking down even strong plastics.

If something shows promise,

it has the potential to be successful in the future.

Since then, that promise has started to come true.

Scientists in France have used LCC to develop new enzymes and

by 2025,

they plan to recycle 50,000 tonnes of plastic waste annually,

including strong plastics

like PET and nylon, which is used to make clothes.

But there's still work to do 50,000 tonnes

sounds a lot,

but not as much as the 400 million tonnes of plastic waste

in your question, Neil.

So, what was the correct answer? Right, I asked you

what else would weigh about 400 million tonnes,

the amount of new plastic

we produce each year.

You guessed all the cars on Earth would weigh the same,

which was... the wrong answer,

I'm afraid Beth. In fact, it was all the people on earth!

OK, let's recap the vocabulary

we've learned in this programme, starting with 'incinerate',

another word for burn. Landfill is a method

of dealing with rubbish by burying it in large holes in the ground.

The adjective 'brittle' means easily broken or

snapped.

Downcycling is recycling,

but in such a way that the resulting product is less valuable

or of lower quality than the original. Enzymes are chemicals found

in living cells which cause changes in other chemicals to happen

while not being changed themselves.

And finally, if something shows promise,

it has a lot of potential for success in the future.

Once again, our six minutes are up,

but remember to join us again next time here at 6 Minute

English. Goodbye

for now. Bye.