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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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Researchers 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 steak,
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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)