Research suggests that enzyme-based plastics recycling is better for the environment

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In a new study, researchers found that using enzymes as a more sustainable approach to recycling polyethylene terephthalate (PET) is a common plastic in disposable beverage bottles, clothing, and food packaging that is becoming increasingly important in addressing the environmental challenges of plastic pollution. The study by researchers from the BOTTLE consortium, including the US Department of Energy’s National Renewable Energy Laboratory (NREL) and the University of Portsmouth, was published in the journal Joule.

The analysis shows that enzyme-recycled PET has potential improvement over traditional, fossil-based methods of PET production in terms of a wide range of energy, carbon and socio-economic impacts. The concept, if further developed and implemented on a large scale, could lead to new opportunities for PET recycling and create a mechanism for recycling textiles and other materials that are also made from PET, which is traditionally not recycled today.

With an annual production of 82 million tons, PET is one of the most frequently produced synthetic polymers in the world; around 54 percent of PET is used in the manufacture of textiles for clothing and fibers for carpets. “Of all plastics produced since the 1950s, less than 10 percent has ever been recycled,” said Avantika Singh, chemical engineer at NREL and first author of a new paper outlining the path to enzyme-based recycling. “Most plastic waste ends up in landfills.”

The article “Techno-economic, life-cycle and socioeconomic impact analysis of enzymatic recycling of poly (ethylene terephthalate)” appears in the journal Joule. Her co-authors are Nicholas Rorrer, Scott Nicholson, Erika Erickson, Jason DesVeaux, Andre Avelino, Patrick Lamers, Arpit Bhatt, Yi Min Zhang, Greg Avery, Ling Tao, Alberta Carpenter and Gregg Beckham, all from NREL; and John McGeehan and Andrew Pickford of the Center for Enzyme Innovation at the University of Portsmouth in the UK who are also members of BOTTLE. BOTTLE aims to address the problem of plastic pollution with two innovative approaches, namely: (1) developing energy-efficient, inexpensive and scalable recycling and upcycling technologies and (2) designing modern plastics in such a way that they are naturally recyclable.

The new research paper deals with the challenge of the recyclability of plastics. While images of discarded bottles floating in oceans and other waterways are a visual reminder of the problems posed by plastic waste, the lesser-considered question remains of what to do with the PET used to make textiles for clothing and fibers for carpets. The researchers modeled a conceptual recycling facility that would hold a fraction of the 3 million tons of PET consumed annually in the United States. The enzymatic recycling process breaks down PET into its two components, terephthalic acid (TPA) and ethylene glycol. Compared to traditional fossil-based production routes, the research team found that the enzymatic recycling process can reduce energy consumption along the entire supply chain by 69 to 83 percent and greenhouse gas emissions by 17 to 43 percent per kilogram of TPA.

In addition, a business-wide comparison of virgin TPA and recycled TPA in the United States shows that the environmental and socio-economic impacts of the two processes are not evenly distributed across their supply chain. The proposed recycling process can reduce the environmental impact by up to 95 percent while delivering up to 45 percent more socio-economic benefits, including local jobs in the recycling facilities. The study also predicts that enzymatic PET recycling can achieve cost parity with the production of virgin PET, underscoring the potential of this enzyme technology to decarbonise PET production and the recycling of PET-rich raw materials such as clothing and carpets.

“This is one of the greatest opportunities,” said Singh. “If we can capture this space – textiles, carpet fibers, and other waste PET plastics that are not currently being recycled – that could be a real game changer.” (ANI)

(This story was not edited by Devdiscourse staff and is automatically generated from a syndicated feed.)


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