Saint-Beauzire (France) (AFP)

And if plastic was no longer a waste? The French green chemistry company Carbios, located in Puy-de-Dôme, has developed enzyme-based processes to rethink the life cycle of plastics and make them recyclable to infinity.

At Carbios, the small technological revolution concerns the recycling of polyethylene terephthalate (PET), which is found mainly in plastic bottles, food packaging and also in textiles via polyester.

This type of plastic contributes 75 million tonnes to the 335 million tonnes of plastics produced each year worldwide.

The most common method to recycle is so far a thermomechanical process, consuming energy and subjecting the plastic to high temperatures that reduce its performance.

"The great innovation of Carbios is to use an enzyme, a biological material, which will depolymerize plastic," explains Alain Marty, scientific director of the company located near Clermont-Ferrand.

To understand how it works, we must imagine the enzyme (a protein) "like a small chisel" that will cut the polymer, a large molecule formed by the sequence of monomers, like a necklace made of different pearls, that the enzyme will release.

Thus, "97% of PET can be depolymerized" in only 16 hours. We get a zero waste plastic, "says the scientist.

Once released, the pearls - or monomers - constituting PET, will be recovered and then purified. "The polymerists can reuse them to redo PET and then a new bottle or a nice blouse," says Marty.

- virtuous circle -

The young society of green chemistry keeps secret the exact nature of its enzyme, discovered in nature.

A protein that has become a nugget in the laboratory: "Often the enzymes do not have the capacity to be effective scissors.All Carbios work is to optimize these enzymes to make them more stable at temperature or more efficient in terms of cutting capacity ", explains this former researcher at Insa Toulouse, whose laboratory TBI (Toulouse Biotechnology Institute) works closely with Carbios.

"The idea is no longer to rely on oil to produce plastic but to produce plastic from waste to infinity, so the plastics industry will enter the virtuous cycle of 'circular economy', continues Mr Marty.

A vision that could quickly become reality. The group has announced in late June have raised almost 14.5 million euros during a capital increase, whose product is to be used primarily to build an industrial demonstrator of its technologies.

Its start in the "Valley of Chemistry" Lyon is scheduled for 2021.

A promise that seduces even the giants of the industry. After L'Oréal and Michelin, three big names in soft drinks - Nestlé Waters, PepsiCo and Suntory Beverage & Food Europe (Orangina) - joined in April the consortium set up by the Auvergne group.

100% recyclable but also 100% compostable. A Carbios subsidiary, Carbiolice, jointly created in 2016 with the SPI investment fund operated by Bpifrance and the Limagrain Ingredients cereal producer, is developing solutions to accelerate the composting of polylactic acid (PLA), a plastic produced from biomass like corn, sugar beet or sugar cane.

This type of plastic is particularly used in the manufacture of disposable crockery, jars of yogurts or coffee capsules, or used as films for sacking and agricultural mulching.

- Marketed next year -

"Carbiolice has introduced the enzymes developed at the heart of an additive that is easy to integrate into traditional plastics processing businesses, without modifying the parameters, investments and functionalities of plastic manufacturing plants," explains Nadia Auclair, CEO of the start-up. -up.

The user can compost his PLA "in less than six months in industrial conditions and in less than a year" at the bottom of the garden.

To carve out a place of choice in this market that promises to be gigantic, Carbiolice has signed a co-development agreement with the world leader in enzyme production, the Danish Novozymes.

Their collaboration is expected to enable the production and supply of enzymes for the production of this next-generation additive, which is scheduled for commercial launch next year.

© 2019 AFP