Tandem Chemical Deconstruction and Biological Upcycling of Poly(ethylene Terephthalate) to β-Ketoadipic Acid by Pseudomonas putida KT2440

Allison Z. Werner, Rita Clare, Thomas D. Mand, Isabel Pardo, Kelsey J. Ramirez, Stefan J. Haugen, Felicia Bratti, Gara N. Dexter, Joshua R. Elmore, Jay D. Huenemann, George L. Peabody, Christopher W. Johnson, Nicholas A. Rorrer, Davinia Salvachúa, Adam M. Guss, Gregg T. Beckham

Research output: Contribution to journalArticlepeer-review

78 Scopus Citations

Abstract

Poly(ethylene terephthalate) (PET) is the most abundantly consumed synthetic polyester and accordingly a major source of plastic waste. The development of chemocatalytic approaches for PET depolymerization to monomers offers new options for open-loop upcycling of PET, which can leverage biological transformations to higher-value products. To that end, here we perform four sequential metabolic engineering efforts in Pseudomonas putida KT2440 to enable the conversion of PET glycolysis products via: (i) ethylene glycol utilization by constitutive expression of native genes, (ii) terephthalate (TPA) catabolism by expression of tphA2IIA3IIBIIA1II from Comamonas and tpaK from Rhodococcus jostii, (iii) bis(2-hydroxyethyl) terephthalate (BHET) hydrolysis to TPA by expression of PETase and MHETase from Ideonella sakaiensis, and (iv) BHET conversion to a performance-advantaged bioproduct, β-ketoadipic acid (βKA) by deletion of pcaIJ. Using this strain, we demonstrate production of 15.1 g/L βKA from BHET at 76% molar yield in bioreactors and conversion of catalytically depolymerized PET to βKA. Overall, this work highlights the potential of tandem catalytic deconstruction and biological conversion as a means to upcycle waste PET.

Original languageAmerican English
Pages (from-to)250-261
Number of pages12
JournalMetabolic Engineering
Volume67
DOIs
StatePublished - Sep 2021

Bibliographical note

Publisher Copyright:
© 2021 The Authors

NREL Publication Number

  • NREL/JA-2800-80145

Keywords

  • Bio-upcycling
  • Metabolic engineering
  • MHETase
  • PETase
  • Plastics upcycling
  • Terephthalic acid

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