Photo credit: Science and Technology Daily News (Reporter Liu Xia) Scientists at the University of Texas at Austin wrote in the latest issue of Nature magazine that they have developed a new enzyme variant FAST-PETase, which can decompose plastics that normally take hundreds of years to degrade in a few hours to a few days. It is expected to greatly promote the recycling of plastics, and really open the curtain of the plastic circular economy.

Professor Hal Alper, who led the latest research, said the new enzyme targeted polyethylene terephthalate (PET), a plastic found in most consumer packaging, including biscuit boxes, soda bottles, fruit and salad packaging, as well as certain fibres and textiles, which accounts for 12 per cent of global waste. Which could amount to billions of tons.

In the latest study, Alper and his colleagues used a machine learning model to create new mutations in a natural enzyme called PETase that predicted which mutations would quickly depolymerize waste plastic at low temperatures. They then studied 51 different plastic containers, five different polyester fibers and fabrics, and all water bottles made from PET. Demonstrating the effectiveness of one of these enzymes, called FAST-PETase.

The researchers noted that the new enzyme variant is able to complete a "circular process" that breaks down the plastic into smaller parts (depolymerization) and then chemically reassembles it (repolymerization). In some cases, these plastics can be completely broken down into monomers in as little as 24 hours.

Recycling is the best way to reduce plastic waste, but globally, less than 10% of plastic is recycled. The most common way to dispose of plastic, apart from throwing it in landfills, is to burn it, but this method is costly, energy-intensive and emits harmful gases into the air. Other alternative industrial processes include glycolysis, pyrolysis and/or methanolysis processes, but these treatment processes are also very energy intensive.

Whereas biological solutions consume much less energy. For the past 15 years, scientists have been working on using enzymes to recycle plastics and have made some progress. But no one has yet figured out how to make enzymes that operate efficiently at low temperatures so they can be better used on a large scale. The latest research confirms that FASTPETase can break down plastic at temperatures below 50 degrees Celsius.

Next, the team plans to scale up production of the enzyme to prepare it for industrial and environmental applications. The researchers say the enzyme could prove useful in waste disposal industries, such as cleaning up landfills. To that end, they are working on a variety of ways to transport these enzymes into the wild to clean up contaminated sites.

Plastic Industry Video