Proteins present new approach to plastic recycling

Circular economy

Switzerland Two EPFL engineers have come up with a revolutionary new method for tackling plastic pollution by harnessing the inner workings of proteins. The result? A whole new way of looking at plastic recycling.

Each human being uses, on average, 30 kg of plastic per year. Given that global life expectancy currently stands at approximately 70 years, each person will discard some two metric tons of plastic in his or her lifetime. Multiply that by the number people on earth – which is growing constantly – and the total is staggering. In light of this, Francesco Stellacci, a full professor and head of the Supramolecular Nanomaterials and Interfaces Laboratory at EPFL’s School of Engineering, began thinking about whether there was a way to solve the problem of used plastics and recycle it more effectively. Stellacci established a collaboration with Prof. Sebastian J. Maerkl in the Bioengineering Institute at EPFL and they decided to co-advise a PhD student, Simone Giaveri, the team has published its conclusions, based on scientific research, in Advanced Materials.

After reviewing the existing plastic-recycling options available, the engineers decided to think up a completely new approach.

A pearl necklace

Proteins are one of the main organic compounds of which our world is made of. Like DNA, they form part of the family of polymers; proteins are long chains of molecules, or monomers, known as amino acids.In the lab, Giaveri initially attempted to replicate this natural cycle, outside living organisms. “We selected proteins and divided them up into amino acids. We then put the amino acids into a cell-free biological system, that assembled the amino acids back into new proteins with entirely different structures and applications,” he explains.

So what’s the connection between protein assembly and plastic recycling? Because both compounds are polymers, the mechanisms naturally occurring in proteins could be applied to plastics as well. While this analogy may sound promising, Stellacci warns that developing such methods won’t happen overnight.