Enzyme selection, optimization, and production toward biodegradation of post–consumer poly(ethylene terephthalate) at scale

Journal Article · Fri Aug 18 04:00:00 EDT 2023 · Biotechnology Journal

DOI:https://doi.org/10.1002/biot.202300119· OSTI ID:2429439

Soong, Ya‐Hue Valerie ^[1]; Abid, Umer ^[2]; Chang, Allen C. ^[2]; Ayafor, Christian ^[2]; Patel, Akanksha ^[2]; Qin, Jiansong ^[2]; Xu, Jin ^[2]; Lawton, Carl ^[2]; Wong, Hsi‐Wu ^[2]; Sobkowicz, Margaret J. ^[2]; Xie, Dongming ^[2]

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1. University of Massachusetts, Lowell, MA (United States); UMass Lowell
2. University of Massachusetts, Lowell, MA (United States)

Poly(ethylene terephthalate) (PET) is one of the world's most widely used polyester plastics. Due to its chemical stability, PET is extremely difficult to hydrolyze in a natural environment. Recent discoveries in new polyester hydrolases and breakthroughs in enzyme engineering strategies have inspired enormous research on biorecycling of PET. This study summarizes our research efforts toward large-scale, efficient, and economical biodegradation of post-consumer waste PET, including PET hydrolase selection and optimization, high-yield enzyme production, and high-capacity enzymatic degradation of post-consumer waste PET. First, genes encoding PETase and MHETase from Ideonella sakaiensis and the ICCG variant of leaf-branch compost cutinase (LCC^ICCG) were codon-optimized and expressed in Escherichia coli BL21(DE3) for high-yield production. To further lower the enzyme production cost, a pelB leader sequence was fused to LCC^ICCG so that the enzyme can be secreted into the medium to facilitate recovery. To help bind the enzyme on the hydrophobic surface of PET, a substrate-binding module in a polyhydroxyalkanoate depolymerase from Alcaligenes faecalis (PBM) was fused to the C-terminus of LCC^ICCG. The resulting four different LCC^ICCG variants (LCC, PelB-LCC, LCC-PBM, and PelB-LCC-PBM), together with PETase and MHETase, were compared for PET degradation efficiency. A fed-batch fermentation process was developed to produce the target enzymes up to 1.2 g L^–1. Finally, the best enzyme, PelB-LCC, was selected and used for the efficient degradation of 200 g L^–1 recycled PET in a well-controlled, stirred-tank reactor. Furthermore, the results will help develop an economical and scalable biorecycling process toward a circular PET economy.

• Research Organization: University of Massachusetts, Lowell, MA (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: EE0008930
• OSTI ID: 2429439
• Alternate ID(s): OSTI ID: 1997039
• Journal Information: Biotechnology Journal, Journal Name: Biotechnology Journal Journal Issue: 12 Vol. 18; ISSN 1860-6768
• Publisher: Wiley
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
Biodegradation
Leaf-Branch Compost Cutinase
PETase
Poly(ethylene terephthalate)
Terephthalic Acid