Since the beginning of the twentieth century, a variety of plastic products have provided a lot of convenience for our lives, but also because of the characteristics of refractory degradation, it has caused a huge burden on the environment in which we live.
PET plastics (scientific name polyethylene terephthalate), which accounts for 12% of all waste in the world, will take hundreds of years to degrade naturally, and today's microplastic pollution has invaded the human body, and it is imperative to solve plastic pollution.
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As a result, people have been trying to "eliminate" these discarded plastic products for many years. While recycling is the most obvious way to reduce plastic waste, less than 10% of the world's plastics can be recycled, and other waste plastics are either thrown into landfills or burned. Not only is it costly and energy-consuming, but it also produces toxic gases.
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In a variety of attempts, such as pyrolysis and the use of methanol, scientists have found an effective way to use enzymes to break down waste plastics. A few years ago, researchers in Japan discovered that a bacterium that "eats" plastic can break down PET plastic within a few weeks under the action of enzymes.
Later, researchers at the University of Portsmouth in the United Kingdom designed a more powerful enzyme, "PETase", and combined it with another enzyme called "MHETase" to form a "super enzyme" that can "eat" PET plastic at six times the speed.
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Not long ago, this enzyme that "eats" plastic became stronger. A team at the University of Texas has made improvements to some of the shortcomings of the "PETase" enzyme, such as its inability to function properly at low temperatures and different pH ranges, the lack of effectiveness in directly treating untreated plastic waste, and the slow response speed.
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To make the "PETase" enzyme stronger, the researchers developed a machine learning model that predicts which mutations in the enzyme can remove these obstacles, such as how to quickly depolymer the waste plastics left behind after consumption at low temperatures.
Using machine learning predictions and studies, the researchers designed an enzyme that is more functional, active, stable and tolerant, called "FAST-PETase."
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In tests, the "FAST-PETase" enzyme degraded almost completely in one week 51 different consumer-generated plastic containers, 5 different polyester fibers and fabrics, and water bottles made of PET. In some experiments, it can even break down plastics in as little as 24 hours.
Through testing, researchers have verified its effectiveness. What's more, the "FAST-PETase" enzyme not only decomposes faster, but also works at temperatures below 50 degrees Celsius, which means it can be used more widely.
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Next, the team plans to scale up the production of enzymes in preparation for industrial and environmental applications. Researchers have filed patent applications for the technology and plan several different uses, such as cleaning up landfills, and are working on multiple ways to bring enzymes into the fields to clean up contaminated sites, planning to use it for environmental remediation.
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The impact of waste plastics on us has been too much and too long, and the emergence of the "FAST-PETase" enzyme is a common wisdom of many disciplines such as synthetic biology, chemical engineering and artificial intelligence, and it is also a feasible way to deal with plastic pollution. It is hoped that with its power, the pollution caused by plastic products can gradually disappear in our environment.