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DOE OSTI · 3013265

Mixed polyamide and polyester upcycling via chemical autoxidation and engineered Pseudomonas putida

Eaglesfield, Ross [National Renewable Energy Laboratory (NREL), Golden, CO (United States); BOTTLE Consortium, Golden, CO (United States)]·Frey, Brandon L. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); BOTTLE Consortium, Golden, CO (United States)]·Lahive, Ciaran W. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); BOTTLE Consortium, Golden, CO (United States); Univ. of Manchester (United Kingdom)]·Cuthbertson, Amy A. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); BOTTLE Consortium, Golden, CO (United States)]·Kuatsjah, Eugene [National Renewable Energy Laboratory (NREL), Golden, CO (United States); BOTTLE Consortium, Golden, CO (United States)]·Ramirez, Kelsey J. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); BOTTLE Consortium, Golden, CO (United States)] (ORCID:000000025114742X)·Avina, Young-Saeng [National Renewable Energy Laboratory (NREL), Golden, CO (United States); BOTTLE Consortium, Golden, CO (United States)]·Alt, Hannah [National Renewable Energy Laboratory (NREL), Golden, CO (United States); BOTTLE Consortium, Golden, CO (United States)]·Banakis, Natalie [Patagonia, Inc., Ventura, CA (United States)]·Knauer, Katrina M. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); BOTTLE Consortium, Golden, CO (United States)] (ORCID:0000000201257532)·Beckham, Gregg T. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); BOTTLE Consortium, Golden, CO (United States)] (ORCID:000000023480212X)·Werner, Allison Z. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); BOTTLE Consortium, Golden, CO (United States)] (ORCID:0000000171472863)
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Abstract

Polyamides, such as nylons, are often used in multi-component materials, like textiles and packaging, and are accompanied with unique recycling challenges. Recently, autoxidation and bioconversion has emerged as a tandem approach for the conversion of mixed plastics waste to single products, however the fate of polyamides in these processes is unknown. Here, we optimized the autoxidation of nylon-6 and nylon-6,6 depolymerization, achieving >92 mol% nitrogen recovery from both substrates, predominantly as acetamide, and 20–27 mol% carbon recovery (not including acetamide). Experiments with 13 C-labeled acetic acid demonstrated that the carbon in acetamide was solvent derived. Autoxidation of mixed nylon-6 and poly(ethylene terephthalate) (PET) post-consumer fibers resulted in similar carbon and nitrogen recoveries from nylon, while PET was depolymerized to terephthalic acid (TPA) at >65 C-mol% recovery. Next, we engineered Pseudomonas putida KT2440 to utilize acetamide as the sole carbon and nitrogen source for growth through the constitutive expression of genes encoding amidase enzymes, including a native amidase (PP_0613) shown to be active on C 2 –C 4 amides. Heterologous chromosomal expression of amiE, encoding the amidase from P. aeruginosa, was found to be superior to PP_0613 constitutive expression in genome integrated strains. Prior engineering to enable TPA conversion to β-ketoadipate pathway intermediate protocatechuate was leveraged and combined with deletion of pcaD to produce muconolactone as a product. Finally, a stacked strain engineered for conversion of acetamide, TPA, and DCAs was evaluated on the reaction product from autoxidation of mixed post-consumer nylon and PET fibers without any supplemental nitrogen, achieving quantitative yields in the presence of supplemental carbon.

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37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRYacetamidedepolymerizationnylonpoly(ethylene terephthalate)post-consumer fibers

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Eaglesfield, Ross [National Renewable Energy Laboratory (NREL), Golden, CO (United States); BOTTLE Consortium, Golden, CO (United States)], Frey, Brandon L. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); BOTTLE Consortium, Golden, CO (United States)], Lahive, Ciaran W. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); BOTTLE Consortium, Golden, CO (United States); Univ. of Manchester (United Kingdom)], Cuthbertson, Amy A. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); BOTTLE Consortium, Golden, CO (United States)], Kuatsjah, Eugene [National Renewable Energy Laboratory (NREL), Golden, CO (United States); BOTTLE Consortium, Golden, CO (United States)], Ramirez, Kelsey J. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); BOTTLE Consortium, Golden, CO (United States)] (ORCID:000000025114742X), Avina, Young-Saeng [National Renewable Energy Laboratory (NREL), Golden, CO (United States); BOTTLE Consortium, Golden, CO (United States)], Alt, Hannah [National Renewable Energy Laboratory (NREL), Golden, CO (United States); BOTTLE Consortium, Golden, CO (United States)], Banakis, Natalie [Patagonia, Inc., Ventura, CA (United States)], Knauer, Katrina M. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); BOTTLE Consortium, Golden, CO (United States)] (ORCID:0000000201257532), Beckham, Gregg T. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); BOTTLE Consortium, Golden, CO (United States)] (ORCID:000000023480212X), Werner, Allison Z. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); BOTTLE Consortium, Golden, CO (United States)] (ORCID:0000000171472863). 2025-09-19. Mixed polyamide and polyester upcycling via chemical autoxidation and engineered Pseudomonas putida. https://doi.org/10.1039/d5re00351b

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