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How to digest plastic and save the world

Toronto team wins gold standard at international synthetic biology event
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The iGEM Toronto team researched the PETase protein as part of their project. ADAM LAM/THE VARSITY
The iGEM Toronto team researched the PETase protein as part of their project. ADAM LAM/THE VARSITY

Hundreds of students, from graduate to high school studies, gathered in Boston to present their research at the International Genetically Engineered Machine (iGEM) Foundation’s Giant Jamboree in early November. Over the past year, they’ve been developing projects in the emerging field of synthetic biology, which uses modern tools and biological building blocks to solve natural problems.

This year, iGEM Toronto, the University of Toronto team, returned with more than just the standard bragging rights. Rather, their project was recognized with a gold standard — the highest evaluation for a project in the iGEM competition — and they were nominated for the best manufacturing project in their competitive category.

What was the team’s project?

Over the past year, the team has conducted cutting-edge research on a possible solution to the world’s plastic waste problem. Three years ago, a team of researchers in Japan discovered a unique strain of bacteria that can break down a common type of plastic, polyethylene terephthalate — commonly called PET plastic — on a molecular level, essentially digesting it.

At the moment, plastics can only be recycled a finite number of times before they start to degrade and have to be disposed of. However, if researchers find a way to break plastics down to their molecular components, they could apply this to make a near-perfect recycling system for plastic.

Recyclers could then recreate the plastics from scratch to be as good as new, with negligible amounts of waste.

Since their conception, the iGEM Toronto team has been designing and testing ways to implement this recycling process in an industrial setting. The recently-discovered bacteria uses a particular protein, called PETase, to break down the plastics that it digests.

How the team collaborated to win gold

The team’s computational lab created the necessary tools to redesign the protein so that it could process plastics quicker, while keeping them sturdy enough to survive in an industrial setting. Building on the work of researchers like Dr. Jennifer Listgarten and David Brookes, several team members trained a neural network to search for more efficient versions of the protein.

Others used protein-modelling software to redesign PETases, giving them more useful chemical properties. Together, they modelled five alternate versions of the protein, hoping that some would be more efficient at digesting plastics than naturally-occurring PETases.

In the final analysis, all versions of the protein were successful.

The team’s biology lab then produced millions of copies of these proteins in order to test their practical efficiency. Other members of the team interviewed experts to get a better understanding of the current recycling industry, and developed preliminary models for a PETase ‘bioreactor’ that could be used in a recycling plant.

The impact of iGEM’s success

The research team considers the victory to be a huge validation. “I was able to lead a team of people who never knew each other at first, and now could come up with something that’s now on a world stage, and is worth it,” said Amy Yeung, the outgoing president of iGEM Toronto, in an interview with The Varsity.

“That sense of feeling of accomplishment, from when I’ve started to now, is the best thing I think I’ve picked up.”

What’s more, the iGEM program at U of T has the potential to set a precedent for undergraduate research. “A lot of undergrads get stuck just doing somebody’s side jobs in a lab,” said Daniel Kiss, who took over as the club’s co-president this year, to The Varsity.

iGEM Toronto’s research model is different. Although their projects are designed and run by members from a wide variety of programs — from computational biology to ethics — they’re almost entirely undergraduates.

“It’s like Lord of the Flies, but [with a] happy ending,” joked Kiss. “Let’s put all these undergrads in a room and see what happens.”