On April 27, Nature published a paper by Professor Hal Alper's team at the University of Texas at Austin on how modifying an enzyme with the help of machine learning could reduce the degradation time of plastics measured in centuries to 24 hours to a few days. The news has sparked concern because the result may solve a century-old dilemma: limiting and minimizing the harm of plastics to human society, nature and ecology.
The invention of plastic and the iterative renewal of plastic products is an innovation of mankind to develop economy and improve life by using the earth's resources, which is undoubtedly called a great invention. However, 100 years after the invention of the plastic bag, European environmental groups named it "the worst invention of mankind in the 20th century", plastic on people, organisms and environmental hazards are becoming increasingly serious.
Each year, a staggering 300 million tons of plastic are produced worldwide, but when plastic products are finished with their mission, humans are not able to dispose of them effectively. Burning plastics can cause environmental hazards, such as the production of large amounts of dioxins and other pollutants, which can also endanger plants, crops and ecology once they enter the soil. At the same time, nearly 80 percent of the world's plastic products end up in landfills and dumps, polluting local soil and water, and also appearing as microplastics in human blood, feces and even the placenta through the drinking water and food chain.
Various measures have been proposed internationally to limit the harm caused by plastic products by limiting the production and use of plastic products, adopting alternatives, recycling plastic products, and putting plastics into a recyclable mode.
China in 2008 on the implementation of the "Plastic Restriction", which provides for a nationwide ban on the production, sale and use of plastic shopping bags less than 0.025 mm thick, all supermarkets, shopping malls, marketplaces and other retail venues are not free to provide plastic shopping bags. In 2020, a number of provinces and cities across the country also introduced an upgraded version of the "plastic restrictions" local regulations.
Nonetheless, it has been found that plastic products are forbidden and create many economic and social benefits while satisfying people's needs. Global annual plastic production has grown from 5 million tons in the 1950s to 300 million tons today because plastics are inexpensive and extremely durable and versatile.
To increase the yield and usage of a product, you can think at the source and at the end. Now it seems unrealistic to ban the production and use of plastic products, then we have to find a way out for it - recycling.
Technology offers the possibility of providing an outlet for plastics to degrade and be recycled. Previous studies have found that PETase enzymes can degrade PET (polyethylene terephthalate), but also have the obvious drawbacks of only working at a specific pH and temperature range and having a limited reaction rate, and requiring pretreatment of the plastic prior to degradation. Now, a team of researchers at the University of Texas at Austin has used machine learning models to modify PETase to develop a completely new enzyme: FAST-PETase (Functional, Active, Stable and Tolerant PETase), which can depolymerize and degrade PET into small molecules at temperatures below 50 degrees Celsius and under a range of different acid and alkaline conditions. Under some conditions, these plastics can be completely degraded to monomers in just 24 hours.
Therefore, this also offers several ways of plastic outlets, rapidly degrading plastic, and also using this enzyme for environmental remediation, cleaning up contaminated areas, and helping companies recycle plastic at the molecular level.
Technology, which offers new possibilities for the future of plastics. We look forward to a return to a greener earth with the addition of technology.
