French company uses enzymes to recycle one of the most common single-use plastics

Because single-use plastics are largely derived from petroleum, by 2050 plastics could account for 20% of the world’s annual oil consumption. Reducing our dependence on plastics and finding ways to reuse the plastic already in the world could significantly reduce emissions.

At present, only about 15% of all plastics around the world are collected for recycling each year. Researchers have been trying since the 1990s to find new ways to break down plastics in the hope of recycling more. Companies and researchers have worked to develop enzymatic processes, like the one used at Carbios, as well as chemical processes, like the method used by Loop Industries. But it is only recently that enzymatic and chemical processes have started to be commercialized.

Carbios’ new reactor measures 20 cubic meters, about the size of a pickup truck. It can hold two metric tons of plastic, the equivalent of about 100,000 crushed 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 approximately 20 times the size of the demonstration reactor. This large-scale plant will be built near a plastics manufacturer somewhere in Europe or the United States, and is expected to be operational by 2025, according to Alain Marty, Scientific Director of Carbios.

Carbios has been developing enzymatic recycling since the creation of the company in 2011. Its process relies on enzymes to cut the long chains of polymers that make up plastic. The resulting monomers can then be purified and chained to make new plastics. Carbios researchers started with a natural enzyme used by bacteria to break down leaves, then modified it to make it more efficient at breaking down PET.

Carbios demonstration facility in Clermont-Ferrand, France. Image courtesy of SkotchProd.

Carbios estimates that its enzymatic recycling process reduces greenhouse gas emissions by around 30% compared to virgin PET. Marty says he expects that number to increase as they troubleshoot issues.

In a recent report, the researchers estimated that making PET from enzymatic recycling could reduce greenhouse gas emissions by between 17% and 43% compared to making virgin PET. The report wasn’t specifically about Carbios, but it’s probably a good estimate of his process, according to Gregg Beckham, researcher at the US National Renewable Energy Laboratory and co-author of the report.

While the development of new enzymes has been a major focus of research and commercial efforts, other parts of the process will determine the efficiency and cost-effectiveness of the technology, says Beckham, who leads a consortium on new plastic recycling and production methods.

“It’s all the less glamorous,” Beckham says, like putting plastic in a form that enzymes can break down efficiently or separating what the enzymes spit out, which can take a lot of energy and time, and increase costs. emissions and costs. .

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