Bio-recycling is coming into fashion with enzymes that will eat your shoes


Imagine bringing a used pair of sneakers or used yoga pants back to the brand that produced them, knowing that the polyester material they are made from will be biologically broken down into its basic building blocks and then used to make a new pair of sneakers. brilliant. or yoga pants or anything, really, that’s made of polyester. Which, by the way, does a lot.

It’s the future that a biotech startup called Carbios and a group of well-known sportswear brands are working on. The French startup, which has developed an enzymatic process for the degradation of polyethylene terephthalate (commonly known as PET), recently signed an agreement with On, Patagonia, Puma and Salomon intended to accelerate the commercialization of its textile bio-recycling technology.

The consortium aims to develop the industry’s first large-scale fiber-to-fiber polyester recycling system, a process that could play a significant role in the circularity of fashion.

Brands “can use plastics to make fibers, but they don’t have a solution for large-scale fiber-to-fiber recycling,” Emmanuel Ladent, CEO of Carbios, said in an interview.

At the same time, Carbios has partnered with PET maker Indorama Ventures to build and operate the world’s first commercial-scale bio-recycling plant for PET-based plastic in Lunéville, a commune (or township) from the Meurthe et Moselle region in France. The company expects the facility, which will recycle local plastic waste, to start operating in 2025.

PET is a petroleum-derived polymer that is primarily used to make three products: plastic bottles: carpet; and clothes. The apparel industry refers to PET as polyester, a pet name for a pet fabric that has become the most widely used fiber in the world, comprising more than 50% of the fibers produced globally.

In the United States alone, more than 34 billion pounds of clothing waste is created each year, much of which ends up in the trash.

Often mixed with other fabrics, such as cotton, and usually accompanied by accessories such as buttons, zippers and labels, polyester can be found in all types of clothing, sportswear and footwear. . This design complexity makes our clothing and footwear notoriously difficult to recycle using conventional technologies. Many clothing and footwear brands use “recycled polyester” to some extent – in products often marketed as containing “ocean” or “ocean-related” plastic – but this material comes from recycled plastic bottles from conventional way, not used clothes.

Although this practice reduces the amount of single-use plastics that end up burned, landfilled or in the ocean and other waterways, recycled polyester from plastic bottles does not solve the gargantuan problem of post-harvest waste. fashion consumption. In the United States alone, more than 34 billion pounds of clothing waste is created each year, much of which ends up in the trash.

A “truly circular” solution

Carbios uses one of the few microbes, discovered by various scientists, that have developed a taste for PET. The company’s enzyme was first identified in compost and has been modified by its own scientists to work faster and work at higher temperatures where PET is softer.

Carbios says its enzyme is also able to selectively break down the polyester material, recovering virtually all of the polyester from textile waste, even mixed fabrics. And unlike conventional recycling, which degrades the quality of PET, limiting the number of times it can be recycled, as well as the amount to be used in a given product, enzymatic recycling breaks down PET at the molecular level, so it is possible to recreate a virgin quality material that can be recycled again and again, making the process, in theory at least, truly circular.

“In the world of traditional recycling, the solutions aren’t circular. You can recycle materials one, two, three times, and then you’re done. With our technology, it’s almost endless,” said Ladent, who has joined Carbios late last year, replacing co-founder and CEO Jean-Claude Lumaret, who led the company since its inception in 2011.

French sports equipment maker Salomon, whose use of recycled polyester currently peaks at 38%, believes the collaboration with Carbios will enable it to produce a 100% recycled polyester product, according to sustainability manager Olivier Mouzin. shoes within the company. “We believe we can produce recycled polyester with the same mechanical properties as virgin, which is not the case today,” he said.

Under the terms of the two-year agreement, the brands will collect post-consumer clothing containing polyester, as well as work on developing sorting and dismantling technologies. In turn, Carbios will supply them with bio-recycled polyester made from these garments.

Mouzin believes it will take several years to reach the point where Salomon could actually produce a product using Carbios’ technology. The best case scenario might be a small pilot project starting in 2026 or 2027.

Enzymes hungry, hungry

Scientists have been studying plastic-degrading enzymes for a few decades.

By the mid-2010s many of these enzymes were known, but it was in 2016 that a key discovery was made. Researchers led by microbiologist Kohei Oda of the Kyoto Institute of Technology in Japan discovered a bacterium called Ideonella sakaiensis 201-F6 outside a bottle recycling facility that could not only break down and metabolize PET, but also use plastic as the main source of nutrients.

The key to this ability was a pair of unique enzymes made by the bacteria. The first (PETase) breaks down long PET molecules into smaller molecules, and a second (MHETase) then produces ethylene glycol and terephthalic acid, the chemical building blocks of PET. Thus, Ideonella sakaiensis 201-F6 can completely reverse the manufacturing process of PET.

In the traditional world of recycling, the solutions are not circular. You can recycle the materials once, twice, three times, and then you’re done. With our technology, it’s almost infinite.

This discovery has boosted research on enzyme recycling and led to new advances. While studying the PETase enzyme from Ideonella sakaiensis, researchers from the University of Portsmouth in the UK and the US Department of Energy’s National Renewable Energy Laboratory (NREL) produced a three-dimensional structure of the PETase enzyme which they then modified to help them better understand how it worked. In doing so, they inadvertently engineered the enzyme, making it even more effective at degrading PET.

This research was led by John McGeehan, Director of the University’s Center for Enzyme Innovation, and Gregg Beckham, Principal Investigator and Group Leader at NREL.

Then in 2020, McGeehan’s team reported that they had linked the enzymes PETase and MHETase together. This “super-enzyme” could eat PET about six times faster than the two enzymes working separately. Other research groups have produced their own modified enzymes, such as Carbios, whose process was validated on the cover of the scientific journal Nature the same year.

The Carbios scientists studied various enzymes, including PETase from Ideonella sakaiensis, but found that leaf and branch compost (LCC) cutinase outperformed the other enzymes they tested. With the modifications made by Carbios scientists, which allow the enzyme to work faster and operate at high temperatures, it remains at the forefront of technology in the literature, Beckham said in an interview.

“To my knowledge, this remains the best enzyme or at least among the best enzymes reported,” he said. Still, Carbios faces some significant challenges, namely energy intensity and cost.

Carbios’ process requires heat treatment and low-temperature grinding of the PET waste – the polyester shirt or the plastic bottle – before it is placed in a bioreactor with the enzymes. And the PET heating and grinding processes are energy-intensive, Beckham said. “There are innovations that are needed to reduce the energy intensity of enzymatic recycling of PET,” he said. “The dream is that you can take clothes made from textile waste or plastic bottles and just drop them in the enzyme reactor and leave. I have no idea when or even if we’ll get there, but that would be super cool .”

Then there’s the cost, which Mouzin says is a challenge. “But we have to explore it with Carbios. We have to work on it if we want to preserve the planet,” he said.

Given the extreme industry interest in the concept, enzyme recycling has the potential to scale relatively quickly, said Beckham, who is also the CEO of the BOTTLE Consortium, a research initiative funded by the U.S. Department of Energy (DOE) which was launched in 2020 to help drive the commercialization of various new technologies (including but not limited to enzyme recycling) to address the problem of plastic waste.

BOTTLE, which stands for “Bio-Optimized Technologies to keep Thermoplastics out of Landfills and the Environment”, is made up of five DOE national laboratories and five universities, four in the US and McGeehan’s team in the UK. The consortium is working with industry partners, including Amazon, Patagonia, Ocean Foundation, Kraft and Heinz, in its efforts to accelerate these technologies.

The University of Portsmouth has also set up Revolution Plastics, which aims to build links between academia and industry and has a joint doctorate. project with Coca-Cola.

In terms of commercialization of enzymatic plastic recycling, Carbios is the most advanced. The startup has been making progress for several years, largely thanks to partnerships with larger companies. In 2017, Carbios and L’Oréal (French) co-founded a consortium to help industrialize its plastic packaging bio-recycling process, which led to the creation of food-grade and proof-of-concept bottles with consortium partners PepsiCo, Nestlé Waters and Suntory Beverages and Food.

Then in September 2021, Carbios opened a demonstration plant in Clermont-Ferrand, France, where it is testing its plastic bio-recycling system. This led to the partnership with Indorama Ventures, one of the largest PET manufacturers with 22% of the market, to build and operate a commercial scale plant. The approximately $206 million facility will have an estimated processing capacity of 50,000 tonnes of PET waste per year, the equivalent of 2 billion bottles. Carbios also expects the plant to create around 150 direct and indirect full-time jobs.

And there’s more to come, Ladent said.

“Next year we plan to start licensing our technology, and hopefully we will have a license in the United States soon,” he said. “We would like to start production in the United States in 2026 or around that time.”

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