A portion of this video is
brought to you by Surfshark. The vast majority of the world’s
plastic isn’t recycled … and when it is, we spend more money to achieve less quality.
It’s currently cheaper to keep producing newer plastics — at the much higher cost
of human and environmental health. But nature has evolved in response. Several
species of insects, bacteria, and fungi can break down plastics all on their own. By studying
the enzymes that make this happen, bioengineers are realizing ways to degrade plastics that don't
involve burning them or dousing them in chemical solvents. Going from taking weeks to break down
plastics in early research to just hours recently. And the momentum is building. One company has
successfully developed an enzyme that doesn’t need industrial conditions to work, allowing
consumers to add bioplastics to compost piles at home. We’re already living in a future where it’s
possible to bury a yogurt cup with confidence, knowing it’ll disintegrate the same
way the food scraps will. That’s a big difference from rinsing it out, tossing
it into a bin, and hoping for the best. How did researchers get us here? And does this
mean we can have our plastics and eat them, too? I’m Matt Ferrell … welcome to Undecided. Well, we already know we’re eating our
plastics — and by “we” I mean the entire planet. There’s no doubt about it: the
accumulation of plastic in our water, air, and soil is an exponentially growing problem
with consequences that we aren’t even fully aware of yet. In a previous video I broke down why the
current plastic recycling process isn’t really a recycling process at all. It’s not practical
or profitable, and the numbers don’t lie: A 2017 study estimates that only 9% of all
the plastics humanity has ever created have been recycled. Meanwhile, 80% is either leaching
toxins in a landfill or out disrupting ecosystems. And with plastic appearing virtually
everywhere, right down to our own organs, there’s mounting evidence that we really are
what we eat. However, humans and animals aren’t the only organisms that consume plastic…one way
or another. And this can be exploited for good. With some species of insects, algae, fungi,
and bacteria as inspiration, scientists have genetically engineered approaches to biorecycling
and biodegradation that could someday be more viable than current recycling practices…like
bioplastic that disappears into dirt. Hold that thought, though. How did we ever
come to that? It turns out nature might have been giving us hints all along. So, to
explain how bioengineering has come this far, let’s work from the ground up. Scientists
have actually been identifying species of microbes capable of digesting plastic
as early as the ‘90s. Observations of several species of algae have revealed
their capacity to live on the surfaces of multiple types of plastics and
partially degrade them. We also know of at least 28 species of fungi that can feed
on plastics as sources of carbon or energy. It’s grub for grubs, too. The larval forms of
beetles and moths, like mealworms, waxworms, and superworms, don’t seem to mind munching
on polyethylene, or PE. That’s a promising adaptation considering that of the 400 million
tons of plastics churned out each year, PE makes up the most of it. That’s stuff like shopping bags
… the ones you always see “drifting in the wind” or “blowing down a highway alone.” Worms aren’t picky eaters, either. In a 2018
study, researchers from Stanford University and the University of Oklahoma found that baby
beetles could eat both PE and mixtures of PE and polystyrene, or PS. PS is the foam-y kind: Think
egg cartons, meat packaging, and insulation. During a 2022 experiment, a team of researchers
from the University of Queensland in Australia noticed that superworms can not only bore right
through PS, but continue to function on an all-PS diet. That wasn’t great for their health — for
us, it would be kind of like living off nothing but potato chips as a kid. Still, they did make
it to adulthood alongside their bran-fed peers. Bugs’ stomachs are so big on plastics
because they’re full of secrets. Sure, worms chew their food, but it’s
the chemical, not mechanical, action that really counts. The true stars
of the show are the bacteria inside the insects’ gut biomes, which enable them
to fully digest plastics. And it’s one bacterium in particular that’s kicked off
a global rush to scout for similar species to use as genetic muses. You could say it’s
the world’s most microscopic casting call. And what better place to hunt for plastic-eating
bacteria than at a plastics recycling center? That’s where researchers from the
Kyoto Institute of Technology and Keio University unearthed the bacterial
breakout talent that started it all: in the sludge surrounding a bottle
recycling site in Sakai, Japan. The significance of this needs a little
more context. According to a 2019 report by Plastics Europe, 40% of the global
demand for plastics is for packaging. Products like single-serving drinks, peanut
butter, and detergent are typically packaged in containers made of polyethylene
terephthalate, or PET. Among the many branches of the plastic tree, PET is the
most abundant within the polyester group. On top of this, the majority of PET is
crystalline. This makes it notoriously “recalcitrant” — AKA just plain stubborn … like
a typical 3 year old — so it’s much harder to degrade. The chemical recycling that does work
is more expensive than creating new plastic from scratch, and mechanical recycling reduces PET’s
value. As a result, PET is the most recycled of its plastic peers in the U.S., but only 31%
of it. The European Union recycles about half. When it comes to plastic bottles specifically,
only about 14% are recycled around the world. If only we had a flagellate hero to save the
day. But what’s that on the ground? Is it a worm? Is it a fungus? No — it’s Ideo-nella
sakaie-nsis. With the power of two enzymes…and friendship…a community of
bacteria can break down a thin film of PET. The 2016 discovery of this very hungry
bacterium was a cause for excitement, hope, and inspiration. But every superhero
has a weakness, and in this case, it would be that I. sakainesis does
its thing only when they’re held at a consistent temperature of 30 C (or 86 F).
The process also takes six weeks, and that’s too slow for an industrial scale. Plus, the germ
has its own Kryptonite. Its weapons of choice, the enzymes PETase and MHETase, are no match
against crystalline PET, the most common kind. We can do better than that though, right? When
your weapons aren’t good enough, you upgrade them. Before we get to that upgrade, I’d like to
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Link is in the description below. Thanks to Surfshark and to all of you for supporting
the channel. So, back to the weapon upgrade. Smart enzymes get spliced at the lab. And
spliced they were. Multiple times. In fact, it was a double-mutant of PETase that took
center stage in 2018 when an international collaboration of researchers accidentally
engineered it to perform better than the original. The sequel to PETase
works 20% faster. More crucially, it can gobble up PET with a crystallinity of
roughly 15%. That’s about the same crystallinity you see in the bottles you get out of vending
machines. For comparison, the natural PETase studied by the Japanese research team involved
PET films with a crystallinity of about 1.9%. As an added bonus, this new and improved PETase
can also degrade an up-and-coming bioplastic derived from sugar, polyethylene furanoate (or
PEF). But members of the research team, led by the University of Portsmouth in England and the US
Department of Energy's National Renewable Energy Laboratory (NREL), didn’t want to stop there. They
knew they could go further, concluding that while their results were encouraging, “the performance
would need to be enhanced substantially.” How do you double-time a double-mutant? Where do
you find clues on how to push past an enzyme’s limits? Have you tried the pile of leaves in the
backyard? Because those are the humble origins of the next breakthrough. Plants have cuticles,
too, and just like our own, they’re protective surfaces. The building blocks of this leafy skin
are the all-natural twin polymers cutin and cutan. The story goes that scientists identified
leaf and branch compost cutinase, or LCC, within DNA sampled from a compost heap. As you
might expect from its name, cutinase can break up cutin, and in 2012, scientists found that
it could also snap PET like twigs. The problem is that like a lot of enzymes (and people),
LCC doesn’t work well in high heat, and the target temperature for industrial recycling of
PET is about 75 C, or 167 F. So, LCC hung out behind the curtain as an understudy for a while.
I guess you could say it was a little too “green.” But now the pressure to evolve is on, and
researchers are leaving no stone unturned. In 2020, French researchers from the
University of Toulouse examined the reaction rates of bacterial enzyme mutations,
using LCC as one of its springboards. After studying over 200 variants, the team finally
optimized the fastest iteration of PETase yet, clocking in a minimum 90% degradation over a
mere 10 hours. And it’s not just efficient — it works comfortably at 72 C. This version of
PETase also yields a lot of terephthalate, or TPA, which can then be reprocessed into PET
that’s good as new. Emphasis on “good as new”: this means that the enzyme can produce recycled
plastic with the same properties as factory-fresh. The plot thickened a few months later,
when researchers from the University of Portsmouth and NREL collaboration declared
that they had done it again. By combining the capacities of PETase and MHETase the same
way Ideo-nella sakaie-nsis does in nature, they boosted the speed of their 2018
mutation of PETase six times over. More recently, researchers from the University
of Texas at Austin threw their hat into the ring with yet another PETase that they call
“functional, active, stable and tolerant,” or FAST. With five mutations under its belt,
FAST-PETase stands out from the crowd with its range. It can work between 30 and 50 C and
can officially degrade 51 different PET-based products in a week. In some cases, it only needs
hours or days. The team has patented the method, and as of April 2022, it’s seeking out
corporate partners for commercialization. That brings us back to today, when it
seems that science has a pretty strong grip on biodegrading PET. But whether these
developments are substantial enough to make a dent in plastic waste is still questionable.
Enzymes can require a variety of specialized conditions. Just among the PETases we’ve
covered, each operated under different temperatures. And even if an enzyme can easily
be integrated into industrial conditions, that infrastructure doesn’t exist yet.
When simply making more is so cheap, it’ll probably be harder to break plastic
production habits than the plastics themselves. And PET is only one head on the plastic
hydra. We’ve got a dizzying number of other forms to worry about. Something as seemingly
simple as a handful of LEGO, for example, can involve up to at least 12 different plastics,
all of which have been washing up on beaches for decades. The LEGO Group says it wants to work
toward shifting to sustainably sourced plastic by 2030, though. It’s currently prototyping
toy bricks made from recycled PET bottles. That's great and all, but world-changing
technologies are difficult to implement at a commercial scale when solving any kind
of problem. The good news is, though there’s no guarantee that enzymatic plastic degradation
will become the norm, a few enzymes have already begun to prove their mettle out in the real
world, with intriguing results. In 2014, the French company Carbios debuted an enzyme with the
ability to degrade 90% of polylactic acid or PLA, a form of bioplastic, within 48 hours. Working
in tandem with its subsidiary Carbiolice, Carbios achieved certification of the
enzyme “Evanesto” as an additive for PLA packaging in 2020. Once incorporated into
PLA products during manufacturing, Evanesto lets you compost anything from mulching film to
coffee pods at room temperature, right at home. The company claims that items made of PLA
plastic will biodegrade in 255 days (or less), and because PLA is typically sourced from starches
like corn or sugarcane, you don’t have to worry about any toxins or residue left behind. Its
FAQ page even clarifies that you don’t have to waste water by washing out your yogurt cups
before you throw them onto the compost heap. That’s not all. Since September 2021, Carbios
has been in the pilot phase of commercializing its enzymatic PET recycling technology
at a demonstration plant. Last month, the company announced the end of its CE-PET
research project, which it says validated multiple processes at an industrial scale. Carbios
managed to address both plastic and textile PET waste by producing bottles made entirely out
of both. Interestingly, it also substantiated a method of producing white fiber from recycled PET
waste, regardless of the original plastic’s color. While not everyone in the plastics and
petrochemical industries is optimistic about enzymatic recycling, Carbios has
received funding from the French State, and the corporations behind several major brands
have also jumped in, including L’Oréal, Nestlé, Pepsi, and Puma. The company plans to establish
its first industrial plant in early 2025. No matter who or what is eating plastic, figuring
out how we clean up our mess is complicated. It’s clear that we can look to algae, fungi, plants,
and bacteria for guidance on how to break plastics, but maybe we’re better off viewing them
as examples of how to build plastics. Seaweed, mycelium fungus, and algae all have the
potential to form our go-to materials someday. As ubiquitous as the plastic we’re
familiar with is now, it hasn’t really been around for that long — and maybe it won’t have
to much longer. Definitely some food for thought. So do you think enzymes like this are
the key to solving our plastic problem? Jump into the comments and let me know. And
be sure to check out my follow up podcast Still TBD where we'll be discussing some
of your feedback. If you liked this video, be sure to check out one of these videos
over here. Thanks to all of my patrons, who get ad free versions of every video, for your
continued support. And welcome to new Supporter+ member Nick Salve. You're helping to reduce my
dependence on YouTube to pay for producing these videos. And thanks to all of you for watching
and commenting. I’ll see you in the next one.
