Engineering enzymes to reduce plastic waste

Overview

Plastic waste is a global pollution crisis. Finding effective solutions to tackle PET plastic pollution is crucial for preserving our environment and creating a more sustainable future.

PET plastic, short for polyethylene terephthalate, is a commonly used material in bottles, containers and packaging. Unfortunately, PET plastic waste has become a significant environmental problem. When not properly recycled, PET can persist in the environment for many years, contributing to pollution in our oceans and ecosystems.

Current recycling methods for PET plastic face several challenges. The processes can be energy-intensive and costly. And the quality of recycled PET may not always be on par with virgin plastic, limiting its usability.

In 2016 scientists found an enzyme, a special type of protein, called IsPETase that can break down PET into its original building blocks. This discovery generated a lot of interest in using biological methods to recycle plastics.

But enzymes such as IsPETase are not immediately suitable to be used on a large scale, as they are not robust or efficient enough for industrial use. Whilst enzymes can be engineered to meet these industrial demands, the process is very challenging when working with plastic degrading enzymes.

In this recording of an online talk, Dr Elizabeth Bell describes the development of a high-throughput platform for engineering plastic degrading enzymes using a process called directed evolution. Directed evolution is a mimic of natural evolution but done on a laboratory scale. It focuses on tailoring the specific properties of an enzyme to meet our requirements.

Elizabeth and her team used this platform to create a new variant of IsPETase that can withstand high temperatures and is more effective at breaking down PET. The engineered enzyme can also selectively degrade the PET component of a multi-material plastic that is commonly used for food packaging.

This study demonstrates that laboratory evolution can be used as a powerful tool to engineer enzymes to effectively break down plastics. With further research and development, these engineered enzymes could play a crucial role in reducing plastic waste and promoting a more sustainable future.