AUSTIN (KXAN) — Plastic has become a giant environmental problem since it first began being mass produced in the 1950s. In 2018, American manufacturers generated nearly 36-million tons of plastic according to the Environmental Protection Agency.
Now, researchers with the University of Texas at Austin may have discovered a solution for this crisis: an enzyme capable of eating plastic.
“There’s a microorganism that was found in a bottle recycling facility that was able to colonize on and start chewing some of the plastic bottles,” said Dr. Hal Alper, a professor of chemical engineering at UT.
The enzyme, nicknamed FAST-PETase, eats a specific type of plastic, PET. This plastic is the type found in water bottles and food packaging. Around 30% of plastic manufactured is used to make water bottles.
According to the World Wildlife Fund, it takes 450 years for a plastic water bottle to decompose in nature. The enzyme can decompose that same water bottle in days, Alper said.
“We’re putting this in something that looks like water. Nothing fancy that makes it look like Cool Science. Right? Except for the fact that it is cool science,” Alper said.
Evolving a plastic eater
Enzymes are an essential part of life on Earth. They’re microscopic, found in your cells. Alper says they are found throughout your body and are used to breakdown and build new things.
“I like to think of them as Pac Man,” Alper said. “They chew up those little dots. And in some cases, the dots they do are bringing things together, building it up. Sometimes it’s breaking things apart.”
The enzyme is naturally occurring, Alper added.
“It’s really fascinating that an organism can even adapt to the things that we’re throwing into the environment,” Alper said.
But this doesn’t mean that the enzyme is perfect and could survive without some help.
Andy Ellington with UT’s Center of Systems and Synthetic Biology was asked to develop a way to rapidly evolve the enzyme. To do this, they turned to machine learning.
But how, exactly, does machine learning work?
Well, Ellington said, you ask it “what a cat looks like. You give it literally hundreds and hundreds and hundreds and hundreds of pictures of cats. And then you show it a new picture, it will say this cat is not a cat, right? What it’s learning is essentially cat-itude: It’s learning whatever features in the image make a cat. We did exactly the same thing. Except we said, ‘here are all [the enzymes] in the world.’”
Ellington and his students were able to use this data to determine what attribute the plastic-eating enzyme needed to better survive. They then added these attributes to the enzyme.
How does the Plastic Eating Thing work?
Alper said the enzyme can eat some types of plastic better than others. Water bottles, for instance, have a coating on them that the enzyme has to work through.
“To get it to work on these plastic bottles, we need to melt them first. So we just go through a very low temperature but quick melting process,” Alper said. “And then we can take those potentially with our plastic hockey pucks at that point in time and drop it into our process. In the course of less than a week, we can sound completely consumed the plastic there.”
Alper said the only downside of the enzyme is it produces a type of acid when it consumes the plastic.
“Life finds a way”
To use the enzyme commercially, Alper said that a bacteria can be developed that would produce the enzyme. This is where Ellington comes in.
“We routinely consider what are the hazards associated with synthetic biology?” Ellington said, adding that with machine learning, they can develop kill switches in the bacteria to prevent it from getting out of control.
“This is sometimes called the Jurassic Park strategy, where, just as in Jurassic Park, [the dinosaurs] weren’t supposed to get out, because they’d engineer them to only be able to have a specific amino acid,” Ellington said, adding they’ll use a similar strategy to prevent the bacteria from getting out of control.
Ellington said that releasing the enzyme to the public is a ways off. They’re planning to run numerous tests to ensure the can control the enzyme and that it doesn’t pose any risk to the public.
Once commercially available, Alper said they’re hoping the enzyme will be used at landfills, recycling plants and in compost containers you could use at home.
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