One day we may find ourselves having to thank an enzyme if we can reduce the environmental impact caused by plastic. The idea of unleashing a catalyst to help us fight climate change is not new: it dates back to 2016, when a group of Japanese researchers found a bacterium that used enzymes to break down polyethylene terephthalate, better known as PET, in a few weeks. .
An exceptional result, considering that normally it takes even a hundred years to degrade the resin, whose remarkable anti-wear properties and resistance to natural degradation are at the same time a cross and a delight: they represent an advantage as long as PET is useful to us and a serious risk for flora and fauna especially in marine environments when it is used it disposes, so to speak, in a superficial way.
THE ‘PETASE FAST’ CAN START THE CIRCULAR ECONOMY OF PLASTICS
Over the years, the discovery by the Japanese team of researchers has evolved, trusting science that it could evolve and improve further. The study just published in the prestigious journal Nature certifies this. A team from the University of Texas started from the weak points of the technology artificial decomposition based on enzymes (which we also tried to exploit to extend our lives) to find a way out with the help of machine learning.
The reason why the 2016 discovery and subsequent evolutions have not found practical applications so far is mainly due to the inability of the enzyme to operate efficiently at low temperatures and with sometimes very different pH values. The American team worked on these aspects by developing a machine learning model that could predict which mutations of an enzyme PETase they would allow him to go beyond the limits.
To do this, a wide range of PET products was used, from simple containers to water bottles and even fabrics. The resulting “next generation” enzyme was named PETase FASTacronym for Functional, Active, Stable and Tolerantwhich has been shown to break down plastics at temperatures between 30 and 50 degrees Celsius and with a wide pH range.
Tested with over 50 different types of PET products, in some cases it has proved effective enough to degrade the material within 24 hours. The most interesting aspect is that the enzyme breaks down PET (a polymer) into its base element (monomer) from which new plastic objects can then be made, so the decomposition product is something that saves resources. Researchers have patented the technology and hope it can be put into practice.
When considering environmental cleaning applications it is necessary to have an enzyme that works in the environment at room temperature, said Han Alper, author of the study. – This requirement is why our technology will have a huge advantage in the future. […] The possibilities afforded by this state-of-the-art recycling process are endless in all industries. In addition to the obvious one of waste management, it offers companies in all sectors the opportunity to recycle their products. Through the sustainable approach offered by this type of enzymes, we can begin to imagine the launch of a true circular economy for plastics.
Credits opening image: 123RF.