Researchers from several Spanish groups have published in the journal Nature Catalysis an interesting study describing the preparation of a hydrolytic enzyme from mutants of the sea anemone phragacetoxin C redesigned by computational methods. The enzyme, constructed on a pore-forming protein, was assembled in the form of catalytic nanopores on a membrane model. These nanoreactors, whose design is of remarkable elegance, proved capable of breaking down small fragments of poly(ethylene terephthalate) [PET], one of the main industrial polymers whose use in packaging, textiles and a wide variety of commonly used objects is well known.  

The development of hydrolases capable of depolymerizing polyesters is a field of great interest, since it would give rise to a procedure for removing nanoplastics as an alternative to the membrane filtration processes used in wastewater treatment. It is interesting to note that not only poly(ethylene terephthalate), but also many bioplastics are formed by polyesters that, to a greater or lesser extent, will end up disseminated in the environment. Enzymes capable of degrading nanoplastics must have accessible active centers, affinity towards hydrophobic macromolecules and be able to maintain activity once supported, properties that natural enzymes do not satisfy.  

The result obtained in this research is very relevant, since it demonstrates the possibility of using genetic modifications to convert membrane pores into enzymes capable of tackling a reaction of industrial interest. The results of the proof-of-concept described in the paper are very promising, and consisted of the degradation of poly(ethylene terephthalate) nanoparticles of about 100 nanometers in diameter to give rise to a variety of depolymerized oligomers and monomers that should prove to be metabolizable by microorganisms.