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Plastics: you know about them,
you may not love them,
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but chances are
you use them every single day.
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By 2050, researchers estimate
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that there will be more plastic
in the ocean than fish.
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Despite our best efforts,
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only nine percent of all plastic we use
winds up being recycled.
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And even worse,
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plastic is incredibly tough and durable
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and researchers estimate
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that it can take anywhere
from 500 to 5,000 years
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to fully break down.
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It leaches harmful chemical contaminants
into our oceans, our soil,
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our food, our water, and into us.
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So how did we wind up
with so much plastic waste?
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Well, it's simple.
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Plastic is cheap, durable,
adaptable, and it's everywhere.
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But the good news is
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there's something else that's cheap,
durable, adaptable and everywhere.
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And my research shows
it may even be able to help us
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with our plastic pollution problem.
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I'm talking about bacteria.
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Bacteria are microscopic living beings
invisible to the naked eye
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that live everywhere,
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in all sorts of diverse
and extreme environments,
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from the human gut, to soil, to skin,
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to vents in the ocean floor, reaching
temperatures of 700 degrees Fahrenheit.
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Bacteria live everywhere,
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in all sorts of diverse
and extreme environments.
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And as such, they have to get
pretty creative with their food sources.
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There's also a lot of them.
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Researches estimate that there are
roughly five million trillion trillion --
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that's a five with 30 zeros after it --
bacteria on the planet.
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Now, considering that we humans produce
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300 million tons of new plastic each year,
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I'd say that our plastic numbers
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are looking pretty
comparable to bacteria's.
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So, after noticing this
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and after learning
about all of the creative ways
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that bacteria find food,
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I started to think:
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could bacteria in
plastic-polluted environments
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have figured out
how to use plastic for food?
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Well, this is the question that I decided
to pursue a couple of years ago.
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Now, fortunately for me,
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I'm from one of the most
polluted cities in America,
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Houston, Texas.
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(Laughs)
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In my hometown alone,
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there are seven EPA-designated
Superfund sites.
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These are sites that are so polluted,
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that the government has deemed
their cleanup a national priority.
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So I decided to trek around to these sites
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and collect soil samples
teeming with bacteria.
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I started toying with a protocol,
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which is fancy science talk for a recipe.
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And what I was trying to cook up
was a carbon-free media,
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or a food-free environment.
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An environment without the usual
carbons or food
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that bacteria, like us,
humans, need to live.
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Now, in this environment,
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I would provide my bacteria
with a sole carbon or food source.
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I would feed my bacteria
polyethylene terephthalate
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or PET plastic.
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PET plastic is the most widely produced
plastic in the world.
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It's used in all sorts
of food and drink containers,
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with the most notorious example
being plastic water bottles
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of which we humans currently go through
at a rate of one million per minute.
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So, what I would be doing,
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is essentially putting my bacteria
on a forced diet of PET plastic
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and seeing which, if any,
might survive or, hopefully, thrive.
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See, this type of experiment
would act as a screen
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for bacteria that had adapted
to their plastic-polluted environment
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and evolved the incredibly cool
ability to eat PET plastic.
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And using this screen,
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I was able to find some bacteria
that had done just that.
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These bacteria had figured out
how to eat PET plastic.
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So how do these bacteria do this?
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Well, it's actually pretty simple.
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Just as we humans digest carbon or food
into chunks of sugar
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that we then use for energy,
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so too do my bacteria.
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My bacteria, however, have figured out
how to do this digestion process
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to big, tough, durable PET plastic.
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Now, to do this,
my bacteria use a special version
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of what's called an enzyme.
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Now, enzymes are simply compounds
that exist in all living things.
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There are many different types of enzymes,
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but basically, they make
processes go forward,
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such as the digestion of food into energy.
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For instance, we humans
have an enzyme called an amylase
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that helps us digest
complex starches, such as bread,
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into small chunks of sugar
that we can then use for energy.
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Now, my bacteria have
a special enzyme called a lipase
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that binds to big, tough,
durable PET plastic
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and helps break it
into small chunks of sugar
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that my bacteria can then use for energy.
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So basically,
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PET plastic goes from being
a big, tough, long-lasting pollutant
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to a tasty meal for my bacteria.
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Sounds pretty cool, right?
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And I think, given the current scope
of our plastic pollution problem,
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I think it sounds pretty useful.
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The statistics I shared with you
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on just how much plastic waste
has accumulated on our planet
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are daunting.
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They're scary.
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And I think they highlight
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that while reducing, reusing
and recycling are important,
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they alone are not going to be enough
to solve this problem.
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And this is where I think bacteria
might be able to help us out.
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But I do understand
why the concept of bacterial help
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might make some people a little nervous.
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After all, if plastic is everywhere
and these bacteria eat plastic,
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isn't there a risk of these bacteria
getting out in the environment
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and wreaking havoc?
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Well, the short answer is no,
and I'll tell you why.
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These bacteria are already
in the environment.
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The bacteria in my research
are not genetically modified frankenbugs.
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These are naturally occurring bacteria
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that have simply adapted
to their plastic-polluted environment
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and evolved the incredibly gnarly
ability to eat PET plastic.
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So the process of bacteria eating plastic
is actually a natural one.
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But it's an incredibly slow process.
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And there remains a lot of work to be done
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to figure out how to speed up
this process to a useful pace.
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My research is currently
looking at ways of doing this
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through a series of UV
or ultraviolet pretreatments.
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Which basically means
we blast PET plastic with sunlight.
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We do this because sunlight
acts a bit like tenderizer on a stake,
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turning the big, tough,
durable bonds in PET plastic
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a bit softer and a bit easier
for my bacteria to chew on.
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Ultimately, what my research hopes to do
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is create an industrial-scale
contained carbon-free system,
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similar to a compost heap
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where these bacteria can thrive
in a contained system,
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where their sole food source
is PET plastic waste.
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Imagine one day being able to dispose
of all of your plastic waste
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in a bin at the curb
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that you knew was bound for a dedicated
bacteria-powered plastic waste facility.
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I think with some hard work
this is an achievable reality.
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Plastic-eating bacteria is not a cure-all.
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But given the current statistics,
it's clear that we humans,
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we could use a little help
with this problem.
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Because people,
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we possess a pressing problem
of plastic pollution.
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And bacteria might be
a really important part of the solution.
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Thank you.
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(Applause)