Scientists have been exploring the ability of enzymes to chemically recycle plastic for more than a decade. But the novelty here is speed. These researchers from the University of Austin in Texas have developed a mutant enzyme that devours plastic much faster than others. Thanks to artificial intelligence, they have indeed identified five genetic mutations that allow this enzyme to break down Polyethylene terephthalate (PET), a plastic that is used in the composition of most food packaging and bottles in record time. , between 24 hours and just one week, whereas in nature, it takes several decades to decompose this PET.
For this gluttonous super enzyme from Texas, we must continue research and develop the process on an industrial scale. This may take several years, but the chemical recycling of plastic is a booming sector and several manufacturers have announced the imminent establishment of enzymatic recycling plants for PET plastic. There is in particular the American Eastman, the Canadian Loop, and closer to us the company Carbios which plans to recycle soon with enzymes 50,000 tons of waste per year in its factory in Meurthe-et-Moselle.
Once plastic is broken down by enzymes, it doesn’t disappear, it’s just broken down into smaller molecules, the basic monomers, which can then be reused to make new objects. It’s a bit like starting from oil to make plastic, but without oil.
And that’s the whole point of the process, because when you just recycle the plastic by crushing the packaging, the flakes obtained lose quality over time. They cannot be recycled indefinitely. On the other hand, this chemical recycling will allow him not only to manufacture a fleece jacket with old plastic bottles, but also to re-manufacture bottles from the same used fleece a few years later.
This is the promise of circular use. With several downsides, however: this transformation requires energy, it is not neutral and enzymatic recycling has mainly been developed so far for PET, which represents only 12% of global waste. It is therefore still urgent to rethink our use of plastic packaging.