In late September, Carbios, a French startup, opened a demonstration plant in central France to test the use of enzymes to recycle PET, one of the most common single-use plastics and the material used to make most beverage bottles. MIT Technology Review reports: While we’ve had mechanical methods for recycling some plastics, like PET, for decades, chemical and enzyme-based processes could produce purer products or allow us to recycle items like clothes that conventional techniques can’t process. […] Carbios’s new reactor measures 20 cubic meters — around the size of a cargo van. It can hold two metric tons of plastic, or the equivalent of about 100,000 ground-up bottles at a time, and break it down into the building blocks of PET — ethylene glycol and terephthalic acid — in 10 to 16 hours. The company plans to use what it learns from the demonstration facility to build its first industrial plant, which will house a reactor about 20 times larger than the demonstration reactor. That full-scale plant will be built near a plastic manufacturer somewhere in Europe or the US, and should be operational by 2025, says Alain Marty, Carbios’s chief science officer.
Carbios has been developing enzymatic recycling since the company was founded in 2011. Its process relies on enzymes to chop up the long chains of polymers that make up plastic. The resulting monomers can then be purified and strung together to make new plastics. Researchers at Carbios started with a natural enzyme used by bacteria to break down leaves, then tweaked it to make it more efficient at breaking down PET. Carbios estimates that its enzymatic recycling process reduces greenhouse gas emissions by about 30% compared to virgin PET. Marty says he expects that number to increase as they work out the kinks. In a recent report, researchers estimated that manufacturing PET from enzymatic recycling could reduce greenhouse gas emissions between 17% and 43% compared to making virgin PET. The report wasn’t specifically about Carbios, but it’s probably a good estimate for its process, according to Gregg Beckham, a researcher at the US National Renewable Energy Laboratory and a co-author of the report.
Carbios’s product is about twice as expensive as virgin PET, Marty says. By comparison, mechanically recycled PET is only about 50% more expensive than virgin. Marty points out that Carbios’s PET would still only cost about two cents for a small, clear plastic bottle, which he argues is a relatively small expense for manufacturers. Companies may be willing to pay. In a press release earlier this year, Carbios revealed demonstration bottles from partner brands that included PepsiCo and Nestle. Carbios recycled discarded plastic and handed it off to the companies, which used it to make new bottles. Eventually, enzymatic recycling may be able do things that mechanical recycling can’t, like recycle clothes or mixed streams of plastics.
Read more of this story at Slashdot.