The world is dealing with a major plastic pollution crisis. The recent discovery of a plastic-eating enzyme at UT Austin could be a much-needed game changer to address it.

Research suggests that the world is generating twice as much plastic as it did two decades ago, with the majority of it either getting incinerated or ending up in landfills or dispersed in the environment, especially in oceans.

According to the Global Plastics Outlook report published by the Organisation for Economic Co-operation and Development (OECD), only 9% of plastic is successfully recycled while 22% of plastic is mismanaged. 

Because plastic is not naturally biodegradable, teams of researchers and scientists are always devoting time and resources to finding new innovative ways to address the growing problem of global plastic pollution.

Researchers at the University of Texas (UT) at Austin used a new machine learning (ML) algorithm to create a new variant of enzymes that could potentially degrade plastic. 

Understanding the Global Plastic Waste Crisis

The United Nations Environment Programme (UNEP) estimates that around 7 billion tons of plastic produced between 1950 and 2017 became plastic waste that was either dumped or ended up in landfills. Plastic waste can negatively impact the environment and its natural processes, contribute to climate change, and affect millions of people’s livelihoods and the world’s food production capabilities. Chlorinated plastic can spread harmful chemicals if not properly disposed of or degraded, harming the surrounding soil, groundwater, and ecosystems.

Increased amounts of plastic pollution can also impact the health and well-being of humans. Researchers believe that children are exposed to microplastics and their smaller counterparts – called nanoplastics – more often than adults. The latter can also face adverse health effects due to microplastics, including DNA damage and inflammation. If inflammation becomes chronic, adults might need medical intervention to receive proper care.

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It is well known that plastic can also harm the environment and the vulnerable animal populations living in affected areas. With the growing amount of plastic polluting natural lands and waterways across the world, it is crucial to adopt new technologies and develop alternative packaging to solve the root causes of pollution.

Researchers Develop a Novel Plastic-Eating Enzyme

Hal Alper is a lead researcher of the engineering biology team in the McKetta Department of Chemical Engineering at UT at Austin. He is also a professor and fellow of the Les and Sherri Stuewer Professorship in Chemical Engineering at UT.

Alper and his team of engineers and scientists created a variant of an enzyme called hydrolase using an ML algorithm. The enzyme is capable of breaking down PET (polyethylene terephthalate), one of the most common plastics used today, into its component molecules.

The PET polymer is found most often in consumer packaged products, such as soda, salad, and fruit containers, as well as disposable food trays. According to a review in the National Library of Medicine, in 2021, PET packaging accounted for:

Once PET plastic waste breaks down, however, it can be reused to create entirely new PET materials, essentially leading to a circular plastics economy. In the past, attempts in enzymatic degradation were unsuccessful, mainly due to a lack of robustness to acidity (pH), temperature ranges, and slow reaction rates.

During the project, Alper and the team at UT Austin found that the novel plastic-eating enzyme, referred to as FAST-PETase (functional, active, stable, and tolerant PETase), can break down plastics at a much faster rate than other PET hydrolases used in prior studies. It is also capable of degrading both mixed-colour and clear PET plastic products.

Untreated, post-consumer PET from 51 different products was almost completely degraded by the new FAST-PETase enzyme in only one week. At 50C, the team reported that portions of an entire thermally pretreated water bottle and a commercial water bottle could also be broken down.

The Potential Benefits of the Plastic-Eating Enzyme

Because this new enzyme can break down plastics so quickly and on a large scale, it will have virtually limitless potential to assist many industries in their waste reduction efforts.

For many environmental cleanup activities, controlling the outdoor temperature is a major challenge. The plastic-eating enzyme is sensitive to changes in temperature, rendering enzymatic degradation ineffective.

Since the FAST-PETase enzyme degrades plastic and handles variations in temperature simultaneously, it would be effective in non-laboratory conditions. This new discovery could be a major advantage to environmental organisations and other agencies focused on cleaning up the environment.

With enough quantity, the enzyme can clean up landfills, waste plants, and other sites negatively affected by plastic pollution. The plastic-eating enzyme is affordable, portable, and can be applied extensively. The role of ML in this research is critical. Without the model developed by UT’s researchers, the new enzyme discovery might not have been possible.

Harnessing the Power of AI to Solve Environmental Issues

The team at the University of Texas submitted a patent to explore the potential applications for this new technology. The goal is to scale up manufacturing of the FAST-PETase enzyme so it can be used in practical ways within the environmental and industrial sectors. It will be interesting to see the potential impacts of this discovery and whether it will help address the issue of plastic pollution.

Featured Image by CDC on Unsplash

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