A plastic-eating enzyme might eliminate billions of tons of landfill waste

A plastic-eating enzyme might eliminate billions of tons of landfill waste ...

Environmental-throttling plastics are typically difficult to degrade in a matter of hours to days, according to a technique created by engineers and scientists at The University of Texas at Austin.

This study, published today in Nature, may help resolve one of the world''s most pressing environmental concerns: what to do with the billions of tons of plastic waste plunging up in landfills, polluting our natural lands and water. The enzyme has the potential to supercharge recycling on a large scale, which would enable major industries to reduce their environmental impacts by recovering and reusing plastics at the molecular level.

UT Austin''s McKetta Department of Chemical Engineering has stated that there are a wide range of opportunities to leverage this cutting-edge recycling technique. This also provides businesses from all sectors the opportunity to take a lead in recycling their goods. Through these more sustainable enzyme approaches, we may start to envision a true circular plastics economy.

Polyethylene terephthalate (PET), a significant polymer found in most consumer packaging, including cookie containers, soda bottles, fruit and salad packaging, and many fibers and textiles. It makes up 12% of all global waste.

In some instances, the enzyme was able to complete a circular process of dividing the plastic into smaller pieces (depolymerization) and then chemically placing it back together (repolymerization). In some cases, these plastics may be completely broken down to monomers in just 24 hours.

Researchers at the Cockrell School of Engineering and the College of Natural Sciences used a machine learning technique to generate novel mutations to a natural enzyme called PETase that allows bacteria to degrade PET plastics. The experiment determines which mutations in these enzymes would accomplish the purpose of quickly depolymerizing post-consumer waste plastic at low temperatures.

Through this process, the researchers tested 51 different post-consumer plastic containers, five different polyester fibers, and fabrics, all made from PET, and demonstrated the effectiveness of the enzyme, which they called FAST-PETase (functional, active, stable, and tolerant PETase).

According to Andrew Ellington, a professor at the Center for Systems and Synthetic Biology who led the development of the machine learning model, this work demonstrates the value of bringing together different disciplines, from synthetic biology to chemical engineering to artificial intelligence.

Recycling is the most straightforward way to reduce plastic waste. However, globally, less than 10% of all plastic has been recycled. Instead of throwing it in a landfill, it is essential to burn it, which is costly, energy intensive, and carries hazardous chemicals into the air. Other alternative industrial processes include very energy-intensive glycolysis and/or methanolysis.

Biotechnologies require much less energy. For plastic recycling, research has advanced over the past 15 years. However, until now, no one had been able to identify how to make enzymes that would operate efficiently at low temperatures to make them both portable and affordable at large industrial scale. FAST-PETase can perform the process at less than 50 degrees Celsius.

The researchers have filed a patent application for the technology and are dedicating several locations to the environment. However, environmental remediation is another option.

When it comes to environmental cleanup applications, you need an enzyme that can work in the environment at ambient temperatures. This is where our technology has a tremendous advantage in the future, according to Alper.

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