US researchers have used machine learning to design an enzyme capable of degrading certain forms of plastic in just 24 hours, exhibiting stability making it suitable for large-scale use.
L’enzyme FAST-PETase
Scientists are exploring the potential of enzymes to improve plastics recycling for more than a decade, and the last six years have been marked by significant progress. In 2016, a Japanese team identified a bacterium that uses this type of protein to break down plastics PET in just a few weeks. Improved versions of these enzymes, called PETase et MHETase (being able to digest these plastics six times faster), subsequently emerged.
In the context of work recently published in the journal Natureresearchers from theuniversity of texas set out to remedy some of their shortcomings. According to them, the application of the technology has been hindered by the inability to work well at low temperatures and in different pH ranges, the lack of efficiency in the case of untreated plastic waste as well as the overall slowness of the reactions.
In order to solve these problems, the team developed a machine learning model capable of predicting the mutations capable of conferring on the enzyme PETase such abilities. To do this, she closely studied a series of plastic products PETincluding containers, water bottles and fabrics, then used the model to design and develop a new and improved enzyme, dubbed FAST-PETase.
New enzyme found to be more effective at breaking down plastics PET at temperatures between 30 and 50°C and at different pH levels. It degraded almost entirely 51 different products in PET untreated within a week, achieving this performance in just 24 hours in some cases. The scientists also demonstrated a process for recycling the PET in a closed loop, in which the FAST-PETase has been used to break down plastics, and monomers obtained used to chemically reconstruct the material.
Major implications
« When considering environmental remediation applications, an enzyme capable of functioning in the room temperature environment is essential. This requirement is now nearly met, so our technology might have a huge impact in the future. “, valued Hal Alperlead author of the study.
With its ability to quickly break down plastic waste at low temperatures, the researchers believe the enzyme provides a portable and affordable approach that can be taken to industrial scale. A patent has been filed for this technology, which might notably be used in landfills and polluted areas.
« Beyond the obvious waste management industry, it also gives companies in all sectors the opportunity to take the initiative to recycle their products. With these more sustainable enzymatic approaches, we can begin to envision a true circular plastics economy. “, conclude the authors of the study.
