Chemical and biological integrated degradation process for polyethylene terephthalate (PET), for recycling pet

Patent metadata

Field	Value
Publication number	US-12559776-B2
Application number	US-202218278976-A
Country	US
Kind code	B2
Filing date	Feb 25, 2022
Priority date	Feb 26, 2021
Publication date	Feb 24, 2026
Grant date	Feb 24, 2026

Abstract

The present invention relates to a chemical and biological integrated degradation process for PET, for recycling PET, and, more specifically, the present invention provides a PET upcycling technique for producing a high-value product via a chemical pretreatment process of PET, a TPA and EG production process using an enzyme, and a process for converting TPA and EG to PCA and GLA, respectively.

First claim

The invention claimed is:

1 . A method for depolymerizing polyethylene terephthalate (PET) into an oligomer using glycolysis as a process, with betaine acting as the catalyst.

2 . A method of producing a high-value compound from polyethylene terephthalate (PET), comprising:
producing bis(2-hydroxyethyl) terephthalate (BHET) through glycolysis of PET in the presence of betaine as a catalyst; depolymerizing the produced BHET into terephthalic acid and ethylene glycol via mono(2-hydroxyethyl) terephthalate (MHET) through enzymatic hydrolysis; and converting the terephthalic acid into protocatechuic acid (PCA) through bioconversion in the presence of a biocatalyst, or converting the ethylene glycol into glycolic acid (GLA) through fermentation.

3 . The method of claim 1 , wherein the glycolysis of PET is performed by applying microwaves in the presence of an ethylene glycol solvent.

4 . The method of claim 2 , wherein the BHET is hydrolyzed into MHET by IsPETase, and the MHET is hydrolyzed into terephthalic acid and ethylene glycol by IsMHETase.

5 . The method of claim 4 , wherein the IsPETase consists of the base sequence represented by SEQ ID NO: 1, and the IsMHETase consists of the base sequence represented by SEQ ID NO: 2.

6 . The method of claim 2 , wherein the bioconversion of terephthalic acid into protocatechuic acid is performed using microorganisms expressing terephthalic acid 1,2-dioxygenase and 1,2-dihydroxy-3,5-cyclohexadiene-1,4-dicarboxylate dehydrogenase as biocatalysts.

7 . The method of claim 2 , wherein the fermentation of ethylene glycol is performed using ethylene glycol-fermenting microorganisms including one or more selected from the group consisting of Gluconobacter oxydans ( G. oxydans ) KCCM 40109, Clostridium glycolicums , and Pseudomonas putida.

8 . The method of claim 2 , wherein the glycolysis of PET is performed by applying microwaves in the presence of an ethylene glycol solvent.

Assignees

• Univ Korea Res & Bus Found

Inventors

• Kim Kyoung Heon
• Kim Dong Hyun
• Han Dong Oh
• Kim Jae Kyun

Classifications

• C07C67/297

  by splitting-off hydrogen or functional groups; by hydrogenolysis of functional groups · CPC title

• B29K2067/003

  PET, i.e. poylethylene terephthalate · CPC title

• B29B2017/0293

  Dissolving the materials in gases or liquids · CPC title

• C08J2373/02

  Polyanhydrides · CPC title

• C12P7/40

  containing a carboxyl group {including Peroxycarboxylic acids} · CPC title