Bio-upcycling of polyethylene terephthalate

Tiso, Till; Narancic, Tanja; Wei, Ren; Pollet, Éric; Beagan, Niall; Schröder, Katja; Honak, Annett; Jiang, Mengying; Kenny, Shane T.; Wierckx, Nick; Perrin, Rémi; Avérous, Luc; Zimmermann, Wolfgang; O’Connor, Kevin E.; Blank, Lars M.

doi:10.1101/2020.03.16.993592

Cited by 40 publications

(47 citation statements)

References 67 publications

(76 reference statements)

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“…E6, they are primarily able to consume soluble, xenobiotic intermediates. Perhaps these strains could serve as useful sources of TPA catabolic genes for synthetic biology efforts associated with biological plastics recycling and upcycling ( 67 ).…”

Section: Discussionmentioning

confidence: 99%

Characterization and engineering of a two-enzyme system for plastics depolymerization

Knott

Erickson

Allen

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

307

320

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Plastics pollution represents a global environmental crisis. In response, microbes are evolving the capacity to utilize synthetic polymers as carbon and energy sources. Recently, Ideonella sakaiensis was reported to secrete a two-enzyme system to deconstruct polyethylene terephthalate (PET) to its constituent monomers. Specifically, the I. sakaiensis PETase depolymerizes PET, liberating soluble products, including mono(2-hydroxyethyl) terephthalate (MHET), which is cleaved to terephthalic acid and ethylene glycol by MHETase. Here, we report a 1.6 Å resolution MHETase structure, illustrating that the MHETase core domain is similar to PETase, capped by a lid domain. Simulations of the catalytic itinerary predict that MHETase follows the canonical two-step serine hydrolase mechanism. Bioinformatics analysis suggests that MHETase evolved from ferulic acid esterases, and two homologous enzymes are shown to exhibit MHET turnover. Analysis of the two homologous enzymes and the MHETase S131G mutant demonstrates the importance of this residue for accommodation of MHET in the active site. We also demonstrate that the MHETase lid is crucial for hydrolysis of MHET and, furthermore, that MHETase does not turnover mono(2-hydroxyethyl)-furanoate or mono(2-hydroxyethyl)-isophthalate. A highly synergistic relationship between PETase and MHETase was observed for the conversion of amorphous PET film to monomers across all nonzero MHETase concentrations tested. Finally, we compare the performance of MHETase:PETase chimeric proteins of varying linker lengths, which all exhibit improved PET and MHET turnover relative to the free enzymes. Together, these results offer insights into the two-enzyme PET depolymerization system and will inform future efforts in the biological deconstruction and upcycling of mixed plastics.

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Section: Discussionmentioning

confidence: 99%

Characterization and engineering of a two-enzyme system for plastics depolymerization

Knott

Erickson

Allen

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

307

320

View full text Add to dashboard Cite

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“…Especially the enzymatic hydrolysis of PET is currently an intensively investigated field of research [221,222] to make plastic monomers accessible. Recently, Tiso et al [214] used PET that was enzymatically converted into its monomers, ethylene glycol and terephthalate, by a thermostable polyester hydrolase with a yield of 100%. Subsequently, Pseudomonas sp.…”

Section: Anthropogenic Waste Streams As Carbon Sourcementioning

confidence: 99%

“…Analogous to the valorization of natural lignin, anthropogenic plastic polymer waste streams are promising resources for the production of value‐added chemicals due to their high abundance with 359 million tons produced in 2018 with only a minor fraction being recycled. [ 214 ] Many plastics, including polyethylene terephthalate (PET) and polystyrene, consist of aromatic monomers. Their enzymatic or thermochemical depolymerization make the monomers available for biotechnological applications.…”

Section: Biotransformationmentioning

confidence: 99%

“…Recently, Tiso et al. [ 214 ] used PET that was enzymatically converted into its monomers, ethylene glycol and terephthalate, by a thermostable polyester hydrolase with a yield of 100%. Subsequently, Pseudomonas sp.…”

Section: Biotransformationmentioning

confidence: 99%

“…While the first has a potential application as bioplastic, the latter was copolymerized to a novel bio‐based poly(amide urethane). [ 214 ] In this approach terephthalate and ethylene glycol were both fully metabolized to produce non‐aromatic plastics. However, aromatic plastic monomers can also be transformed into other aromatics or derived compounds by the abovementioned funneling approach.…”

Section: Biotransformationmentioning

confidence: 99%

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Pseudomonas as Versatile Aromatics Cell Factory

Schwanemann

Otto

Wierckx

et al. 2020

Biotechnology Journal

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Aromatics and their derivatives are valuable chemicals with a plethora of important applications and thus play an integral role in modern society. Their current production relies mostly on the exploitation of petroleum resources. Independency from dwindling fossil resources and rising environmental concerns are major driving forces for the transition towards the production of sustainable aromatics from renewable feedstocks or waste streams. Whole‐cell biocatalysis is a promising strategy that allows the valorization of highly abundant, low‐cost substrates. In the last decades, extensive efforts are undertaken to allow the production of a wide spectrum of different aromatics and derivatives using microbes as biocatalysts. Pseudomonads are intriguing hosts for biocatalysis, as they display unique characteristics beneficial for the production of aromatics, including a distinct tolerance and versatile metabolism. This review highlights biotechnological applications of Pseudomonas as host for the production of aromatics and derived compounds. This includes their de novo biosynthesis from renewable resources, biotransformations in single‐ and biphasic fermentation setups, metabolic funneling of lignin‐derived aromatics, and the upcycling of aromatic monomers from plastic waste streams. Additionally, this review provides insights into unique features of Pseudomonads that make them exceptional hosts for aromatics biotechnology and discusses engineering strategies.

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Conversion of Polyethylenes into Fungal Secondary Metabolites

et al. 2022

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Waste plastics represent major environmental and economic burdens due to their ubiquity, slow breakdown rates, and inadequacy of current recycling routes. Polyethylenes are particularly problematic, because they lack robust recycling approaches despite being the most abundant plastics in use today. We report a novel chemical and biological approach for the rapid conversion of polyethylenes into structurally complex and pharmacologically active compounds. We present conditions for aerobic, catalytic digestion of polyethylenes collected from post-consumer and oceanic waste streams, creating carboxylic diacids that can then be used as a carbon source by the fungus Aspergillus nidulans. As a proof of principle, we have engineered strains of A. nidulans to synthesize the fungal secondary metabolites asperbenzaldehyde, citreoviridin, and mutilin when grown on these digestion products. This hybrid approach considerably expands the range of products to which polyethylenes can be upcycled.

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Bio-upcycling of polyethylene terephthalate

Cited by 40 publications

References 67 publications

Characterization and engineering of a two-enzyme system for plastics depolymerization

Characterization and engineering of a two-enzyme system for plastics depolymerization

Pseudomonas as Versatile Aromatics Cell Factory

Conversion of Polyethylenes into Fungal Secondary Metabolites

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