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Scientists Introduce Comprehensive Approach for Plastic Recycling

Published on 2021-09-27. Edited By : SpecialChem

TAGS:  Sustainability and Bioplastics   

epfl-plastic-pollution 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.

Francesco Stellacci, 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-advice a Ph.D. student, Simone Giaveri.

Comprehensive Solution for Plastic Pollution

After reviewing the existing plastic recycling options available, the engineers decided to think up a completely new approach. “When we use biodegradable plastics, the degradation process leaves a residue that must be stockpiled or buried. The more land that is allocated for this means the less land available for farming, and there are environmental consequences to consider as bio-degradation products necessarily change the area’s ecosystem,” says Stellacci. So how can we come up with a comprehensive solution to the problem of recycling plastics? Part of the answer could very well come from nature itself.

In the lab, Giaveri initially attempted to replicate the natural cycle of the protein chain, 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,” Giaveri explains. For instance, Giaveri and Stellacci successfully transformed silk into a protein used in biomedical technology. “Importantly, when you break down and assemble proteins in this way, the quality of the proteins produced is the same as that of a newly synthesized protein. Indeed, you are building something new,” Stellacci says.

Connection Between Protein Assembly and Plastic Recycling

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. “It will require a radically different mindset. Polymers are strings of pearls, but synthetic polymers are made mostly of pearls all of the same color, and when the color is different the sequence of color rarely matters. Furthermore, we have no efficient way to assemble synthetic polymers from different color pearls in a way that controls their sequence.”

Stellacci also point out, however, that this new approach to plastic recycling appears to be the only one that truly adheres to the postulate of a circular economy. "In the future, sustainability will entail pushing upcycling to the extreme, throwing a lot of different objects together, and recycling the mixture to produce every day a different new material. Nature already does this," Stellacci concludes.

Source: EPFL


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