L'enzima artificiale che digerisce la plastica

Gli scienziati della Portsmouth University del Regno Unito e del National Renewable Energy Laboratory del Dipartimento dell'Energia degli Stati Uniti hanno incidentalmente modificato un enzima scoprendo che la nuova variante è in grado di digerire più efficacemente il polietilene tereftalato rispetto al suo omologo naturale.
La scoperta è frutto di una ricerca compiuta esaminando la struttura di un enzima naturale trovato in un centro di riciclaggio dei rifiuti in Giappone. La nuova versione della proteina è stata ribattezzata Ideonella sakaiensis 201-F6.

Scientists have created a mutant enzyme that breaks down plastic drinks bottles – by accident. The breakthrough could help solve the global plastic pollution crisis by enabling for the first time the full recycling of bottles.

The new research was spurred by the discovery in 2016 of the first bacterium that had naturally evolved to eat plastic, at a waste dump in Japan. Scientists have now revealed the detailed structure of the crucial enzyme produced by the bug.

The international team then tweaked the enzyme to see how it had evolved, but tests showed they had inadvertently made the molecule even better at breaking down the PET (polyethylene terephthalate) plastic used for soft drink bottles. "What actually turned out was we improved the enzyme, which was a bit of a shock," said Prof John McGeehan, at the University of Portsmouth, UK, who led the research. "It's great and a real finding."

The mutant enzyme takes a few days to start breaking down the plastic – far faster than the centuries it takes in the oceans. But the researchers are optimistic this can be speeded up even further and become a viable large-scale process.