	US 12,473,417 B2
	Method for the enzymatic degradation of polyethylene terephthalate
Alain Marty, Toulouse (FR)
Assigned to CARBIOS, Clermont-Ferrand (FR)
Appl. No. 17/291,291
Filed by CARBIOS, Clermont-Ferrand (FR)
PCT Filed Nov. 5, 2019, PCT No. PCT/EP2019/080253 § 371(c)(1), (2) Date May 5, 2021, PCT Pub. No. WO2020/094646, PCT Pub. Date May 14, 2020.
Claims priority of application No. 1860222 (FR), filed on Nov. 6, 2018.
Prior Publication US 2022/0363861 A1, Nov. 17, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. C08J 11/10 (2006.01); C12N 9/18 (2006.01)

CPC C08J 11/105 (2013.01) [C12N 9/18 (2013.01); C08J 2367/02 (2013.01); C12Y 301/01074 (2013.01)]

17 Claims

1. A process for enzymatic depolymerization of semi-crystalline polyethylene terephthalate (PET) comprising bringing said semi-crystalline PET into contact with an enzyme capable of depolymerizing said semi-crystalline PET, said enzyme selected from cutinases comprising an amino acid sequence having at least 75% identity with SEQ ID NO:1, and further comprising at least one mutation combination selected from: (i) F208I+D203C+S248C+Y92G, (ii) F208W+D203C+S248C+Y92G, or (iii) F208I+D203C+S248C+V170I+Y92G, corresponding to the residues of SEQ ID NO:1, wherein:

a) the semi-crystalline PET has an initial degree of crystallinity of at most 25%;

b) the depolymerization step is carried out at a temperature T equal to the Tg+10° C. of said semi-crystalline PET; and

c) the enzyme has a depolymerization time (tD) of the semi-crystalline PET that is less than the crystallization time (tR) of said semi-crystalline PET, wherein the time tD represents the time required for said enzyme to depolymerize at least 80% of said semi-crystalline PET at said temperature T, and the time tR represents the time required for said semi-crystalline PET to reach a degree of crystallinity of at most 35% at said temperature T.