1
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Ou W, Wang H, Ye Y, Zhao H, Zhang Y, Hou Z. Hydrogenation of the benzene rings in PET degraded chemicals over meso-HZSM-5 supported Ru catalyst. JOURNAL OF HAZARDOUS MATERIALS 2024; 476:134964. [PMID: 38901261 DOI: 10.1016/j.jhazmat.2024.134964] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Revised: 06/02/2024] [Accepted: 06/17/2024] [Indexed: 06/22/2024]
Abstract
Chemical upcycling of waste polyethylene terephthalate (PET) to value-added products can reduce the emission of CO2, microplastics and toxic chemicals. In this work, mesoporous H-type Zeolite Socony Mobil-5 (HZSM-5) supported Ru catalyst (Ru/m-HZSM-5) was synthesized and tested in the hydrogenation of PET degraded chemicals (bis(2-hydroxyethyl) terephthalate, dimethyl terephthalate, diethyl terephthalate, and terephthalic acid). Characterizations disclosed that Ru/m-HZSM-5 catalyst possesses mesopores (a dominant channel of 5.32 nm), enlarged specific surface area (404 m2·g-1), and Ru NPs dispersed highly (40.6 %) compared to that of Ru/HZSM-5. And also, it was found that Ru/m-HZSM-5 was capable for the hydrogenation of benzene rings in these PET degraded chemicals with large sizes (1.09-1.82 nm). In particular, the conversion of BHET and the selectivity of BHCD over Ru/m-HZSM-5 reached 95.5 % and 95.6 % at 120 °C within 2 h. And Ru/m-HZSM-5 could be recycled at least five times without obvious loss of activity and selectivity.
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Affiliation(s)
- Weitao Ou
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, Department of Chemistry, Zhejiang University, Hangzhou 310028, China
| | - Han Wang
- Zhejiang Hengyi Petrochemical Research Institute Co., Ltd., Hangzhou 311200, China
| | - Yingdan Ye
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, Department of Chemistry, Zhejiang University, Hangzhou 310028, China
| | - Huaiyuan Zhao
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, Department of Chemistry, Zhejiang University, Hangzhou 310028, China; Zhejiang Hengyi Petrochemical Research Institute Co., Ltd., Hangzhou 311200, China.
| | - Yibin Zhang
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, Department of Chemistry, Zhejiang University, Hangzhou 310028, China
| | - Zhaoyin Hou
- Key Laboratory of Biomass Chemical Engineering of Ministry of Education, Department of Chemistry, Zhejiang University, Hangzhou 310028, China; Zhejiang Hengyi Petrochemical Research Institute Co., Ltd., Hangzhou 311200, China.
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2
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Li C, Zheng Q, Liu W, Zhao Q, Jiang L. Enhancement of the degradation capacity of IsPETase by acidic amino acids insertion and carbohydrate-binding module fusion. 3 Biotech 2024; 14:195. [PMID: 39131175 PMCID: PMC11306670 DOI: 10.1007/s13205-024-04041-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Accepted: 07/31/2024] [Indexed: 08/13/2024] Open
Abstract
The biocatalytic degradation of poly(ethylene terephthalate) (PET) through enzymatic methods has garnered considerable attention due to its environmentally friendly and non-polluting nature, as well as its high specificity. While previous efforts in enhancing IsPETase performance have focused on amino acid substitutions in protein engineering, we introduced an amino acid insertion strategy in this work. By inserting a negatively charged acidic amino acid, Glu, at the right-angle bend of IsPETase, the binding capability between the enzyme's active pocket and PET was improved. The resulted mutant IsPETase9394insE exhibited enhanced hydrolytic activity towards PET at various temperatures ranging from 30 to 45 ℃ compared with the wild-type IsPETase. Notably, a 10.04-fold increase was observed at 45 ℃. To further enhance PET hydrolysis, different carbohydrate-binding modules (CBMs) were incorporated at the C-terminus of IsPETase9394insE. Among these, the fusion of CBM from Verrucosispora sioxanthis exhibited the highest enhancement, resulting in a 1.82-fold increase in PET hydrolytic activity at 37 ℃ compared with the IsPETase9394insE. Finally, the engineered variant was successfully employed for the degradation of polyester filter cloth, demonstrating its promising hydrolytic capacity. In conclusion, this research presents an alternative enzyme engineering strategy for modifying PETases and enriches the pool of potential candidates for industrial PET degradation.
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Affiliation(s)
- Chuang Li
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, 211816 People’s Republic of China
| | - Qingqing Zheng
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, 211816 China
| | - Wei Liu
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, 211816 China
| | - Quanyu Zhao
- School of Pharmaceutical Sciences, Nanjing Tech University, Nanjing, 211816 People’s Republic of China
| | - Ling Jiang
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, 211816 People’s Republic of China
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing, 211816 China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing, 211816 China
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3
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Du M, Xue R, Yuan W, Cheng Y, Cui Z, Dong W, Qiu B. Tandem Integration of Biological and Electrochemical Catalysis for Efficient Polyester Upcycling under Ambient Conditions. NANO LETTERS 2024; 24:9768-9775. [PMID: 39057181 DOI: 10.1021/acs.nanolett.4c02966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/28/2024]
Abstract
Excessive production of waste polyethylene terephthalate (PET) poses an ecological challenge, which necessitates developing technologies to extract the values from end-of-life PET. Upcycling has proven effective in addressing the low profitability of current recycling strategies, yet existing upcycling technologies operate under energy-intensive conditions. Here we report a cascade strategy to steer the transformation of PET waste into glycolate in an overall yield of 92.6% under ambient conditions. The cascade approach involves setting up a robust hydrolase with 95.6% PET depolymerization into ethylene glycol (EG) monomer within 12 h, followed by an electrochemical process initiated by a CO-tolerant Pd/Ni(OH)2 catalyst to convert the EG intermediate into glycolate with high Faradaic efficiency of 97.5%. Techno-economic analysis and life cycle assessment indicate that, compared with the widely adopted electrochemical technology that heavily relies on alkaline pretreatment for PET depolymerization, our designed enzymatic-electrochemical approach offers a cost-effective and low-carbon pathway to upgrade PET.
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Affiliation(s)
- Mengmeng Du
- Jiangsu Key Laboratory of Pesticide Sciences, Department of Chemistry, College of Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Rui Xue
- College of Biotechnology and Pharmaceutical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211800, China
| | - Wenfang Yuan
- Jiangsu Key Laboratory of Pesticide Sciences, Department of Chemistry, College of Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Yun Cheng
- College of Biotechnology and Pharmaceutical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211800, China
| | - Zhongli Cui
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture and Rural Affairs, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Weiliang Dong
- College of Biotechnology and Pharmaceutical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211800, China
| | - Bocheng Qiu
- Jiangsu Key Laboratory of Pesticide Sciences, Department of Chemistry, College of Sciences, Nanjing Agricultural University, Nanjing 210095, China
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4
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Han H, Song P, Jiang Y, Fan J, Khan A, Liu P, Mašek O, Li X. Biochar immobilized hydrolase degrades PET microplastics and alleviates the disturbance of soil microbial function via modulating nitrogen and phosphorus cycles. JOURNAL OF HAZARDOUS MATERIALS 2024; 474:134838. [PMID: 38850944 DOI: 10.1016/j.jhazmat.2024.134838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2024] [Revised: 05/07/2024] [Accepted: 06/04/2024] [Indexed: 06/10/2024]
Abstract
Microplastics (MPs) pose an emerging threat to soil ecological function, yet effective solutions remain limited. This study introduces a novel approach using magnetic biochar immobilized PET hydrolase (MB-LCC-FDS) to degrade soil polyethylene terephthalate microplastics (PET-MPs). MB-LCC-FDS exhibited a 1.68-fold increase in relative activity in aquatic solutions and maintained 58.5 % residual activity after five consecutive cycles. Soil microcosm experiment amended with MB-LCC-FDS observed a 29.6 % weight loss of PET-MPs, converting PET into mono(2-hydroxyethyl) terephthalate (MHET). The generated MHET can subsequently be metabolized by soil microbiota to release terephthalic acid. The introduction of MB-LCC-FDS shifted the functional composition of soil microbiota, increasing the relative abundances of Microbacteriaceae and Skermanella while reducing Arthobacter and Vicinamibacteraceae. Metagenomic analysis revealed that MB-LCC-FDS enhanced nitrogen fixation, P-uptake and transport, and organic-P mineralization in PET-MPs contaminated soil, while weakening the denitrification and nitrification. Structural equation model indicated that changes in soil total carbon and Simpson index, induced by MB-LCC-FDS, were the driving factors for soil carbon and nitrogen transformation. Overall, this study highlights the synergistic role of magnetic biochar-immobilized PET hydrolase and soil microbiota in degrading soil PET-MPs, and enhances our understanding of the microbiome and functional gene responses to PET-MPs and MB-LCC-FDS in soil systems.
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Affiliation(s)
- Huawen Han
- Centre for Grassland Microbiome, State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agricultural Science and Technology, Lanzhou University, Lanzhou, Gansu Province 730000, China
| | - Peizhi Song
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Lanzhou, Gansu Province 730000, China; State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Yuchao Jiang
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Lanzhou, Gansu Province 730000, China
| | - Jingwen Fan
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Lanzhou, Gansu Province 730000, China
| | - Aman Khan
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Lanzhou, Gansu Province 730000, China; College of Life Science, Northeast Forestry University, Harbin 150040, China
| | - Pu Liu
- Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Lanzhou, Gansu Province 730000, China
| | - Ondřej Mašek
- UK Biochar Research Centre, School of GeoSciences, University of Edinburgh, Crew Building, King's Buildings, Edinburgh EH9 3FF, United Kingdom.
| | - Xiangkai Li
- Centre for Grassland Microbiome, State Key Laboratory of Grassland Agro-ecosystems, College of Pastoral Agricultural Science and Technology, Lanzhou University, Lanzhou, Gansu Province 730000, China; Ministry of Education Key Laboratory of Cell Activities and Stress Adaptations, School of Life Science, Lanzhou University, Lanzhou, Gansu Province 730000, China.
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5
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Mubayi V, Ahern CB, Calusinska M, O’Malley MA. Toward a Circular Bioeconomy: Designing Microbes and Polymers for Biodegradation. ACS Synth Biol 2024; 13:1978-1993. [PMID: 38918080 PMCID: PMC11264326 DOI: 10.1021/acssynbio.4c00077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 06/11/2024] [Accepted: 06/12/2024] [Indexed: 06/27/2024]
Abstract
Polymer production is rapidly increasing, but there are no large-scale technologies available to effectively mitigate the massive accumulation of these recalcitrant materials. One potential solution is the development of a carbon-neutral polymer life cycle, where microorganisms convert plant biomass to chemicals, which are used to synthesize biodegradable materials that ultimately contribute to the growth of new plants. Realizing a circular carbon life cycle requires the integration of knowledge across microbiology, bioengineering, materials science, and organic chemistry, which itself has hindered large-scale industrial advances. This review addresses the biodegradation status of common synthetic polymers, identifying novel microbes and enzymes capable of metabolizing these recalcitrant materials and engineering approaches to enhance their biodegradation pathways. Design considerations for the next generation of biodegradable polymers are also reviewed, and finally, opportunities to apply findings from lignocellulosic biodegradation to the design and biodegradation of similarly recalcitrant synthetic polymers are discussed.
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Affiliation(s)
- Vikram Mubayi
- Department
of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
| | - Colleen B. Ahern
- Department
of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
| | - Magdalena Calusinska
- Department
of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
- Environmental
Research and Innovation Department, Luxembourg
Institute of Science and Technology, L-4422 Belvaux, Luxembourg
| | - Michelle A. O’Malley
- Department
of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
- Department
of Bioengineering, University of California, Santa Barbara, California 93106, United States
- Joint
BioEnergy Institute (JBEI), Emeryville, California 94608, United States
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6
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Wang C, Long R, Lin X, Liu W, Zhu L, Jiang L. Development and characterization of a bacterial enzyme cascade reaction system for efficient and stable PET degradation. JOURNAL OF HAZARDOUS MATERIALS 2024; 472:134480. [PMID: 38703683 DOI: 10.1016/j.jhazmat.2024.134480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 04/15/2024] [Accepted: 04/27/2024] [Indexed: 05/06/2024]
Abstract
The widespread use of polyethylene terephthalate (PET) in various industries has led to a surge in microplastics (MPs) pollution, posing a significant threat to ecosystems and human health. To address this, we have developed a bacterial enzyme cascade reaction system (BECRS) that focuses on the efficient degradation of PET. This system harnesses the Escherichia coli (E. coli) surface to display CsgA protein, which forms curli fibers, along with the carbohydrate-binding module 3 (CBM3) and PETases, to enhance the adsorption and degradation of PET. The study demonstrated that the BECRS achieved a notable PET film degradation rate of 3437 ± 148 μg/(d*cm²), with a degradation efficiency of 21.40% for crystalline PET MPs, and the degradation products were all converted to TPA. The stability of the system was evidenced by retaining over 80% of its original activity after multiple uses and during one month of storage. Molecular dynamics simulations confirmed that the presence of CsgA did not interfere with the enzymatic activity of PETases. This BECRS represents a significant step forward in the biodegradation of PET, particularly microplastics, offering a practical and sustainable solution for environmental pollution control.
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Affiliation(s)
- Chengyong Wang
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, China; College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, China
| | - Rui Long
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, China
| | - Xiran Lin
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, China
| | - Wei Liu
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, China
| | - Liying Zhu
- College of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, China
| | - Ling Jiang
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, China; College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, China.
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7
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Kawai F, Iizuka R, Kawabata T. Engineered polyethylene terephthalate hydrolases: perspectives and limits. Appl Microbiol Biotechnol 2024; 108:404. [PMID: 38953996 PMCID: PMC11219463 DOI: 10.1007/s00253-024-13222-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 06/03/2024] [Accepted: 06/04/2024] [Indexed: 07/04/2024]
Abstract
Polyethylene terephthalate (PET) is a major component of plastic waste. Enzymatic PET hydrolysis is the most ecofriendly recycling technology. The biorecycling of PET waste requires the complete depolymerization of PET to terephthalate and ethylene glycol. The history of enzymatic PET depolymerization has revealed two critical issues for the industrial depolymerization of PET: industrially available PET hydrolases and pretreatment of PET waste to make it susceptible to full enzymatic hydrolysis. As none of the wild-type enzymes can satisfy the requirements for industrialization, various mutational improvements have been performed, through classical technology to state-of-the-art computational/machine-learning technology. Recent engineering studies on PET hydrolases have brought a new insight that flexibility of the substrate-binding groove may improve the efficiency of PET hydrolysis while maintaining sufficient thermostability, although the previous studies focused only on enzymatic thermostability above the glass transition temperature of PET. Industrial biorecycling of PET waste is scheduled to be implemented, using micronized amorphous PET. Next stage must be the development of PET hydrolases that can efficiently degrade crystalline parts of PET and expansion of target PET materials, not only bottles but also textiles, packages, and microplastics. This review discusses the current status of PET hydrolases, their potential applications, and their profespectal goals. KEY POINTS: • PET hydrolases must be thermophilic, but their operation must be below 70 °C • Classical and state-of-the-art engineering approaches are useful for PET hydrolases • Enzyme activity on crystalline PET is most expected for future PET biorecycling.
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Affiliation(s)
- Fusako Kawai
- Graduate School of Environmental and Life Sciences, Okayama University, 1-1-1 Tsushima-Naka, Kita-Ku, Okayama, 700-8530, Japan.
| | - Ryo Iizuka
- Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-Ku, Tokyo, 113-0033, Japan
| | - Takeshi Kawabata
- Graduate School of Information Sciences, Tohoku University, Aoba 6-3-09, Aoba-ku, Sendai, Miyagi, 980-8579, Japan
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8
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Kumar V, Pellis A, Wimmer R, Popok V, Christiansen JDC, Varrone C. Efficient Depolymerization of Poly(ethylene 2,5-furanoate) Using Polyester Hydrolases. ACS SUSTAINABLE CHEMISTRY & ENGINEERING 2024; 12:9658-9668. [PMID: 38966237 PMCID: PMC11220789 DOI: 10.1021/acssuschemeng.4c00915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 06/01/2024] [Accepted: 06/03/2024] [Indexed: 07/06/2024]
Abstract
Poly(ethylene 2,5-furanoate) (PEF) is considered to be the next-generation green polyester and is hailed as a rising star among novel plastics. It is biobased, is nontoxic, and has comparable or improved properties compared to polyethylene terephthalate (PET). Biobased PEF offers lower life-cycle greenhouse gas emissions than PET. However, with its industrial production starting soon, relatively little is known about its actual recyclability. This work reports on the near complete depolymerization of PEF using two efficient PET hydrolases, FastPETase and leaf compost-cutinase (LCC), at loadings 4.5-17 times lower than previously reported. FastPETase and LCC exhibited maximum depolymerization of PEF, measured by weight loss and 2,5-furandicarboxylic acid (FDCA) production, using potassium phosphate-NaOH buffer at 50 and 65 °C, respectively. The 98% depolymerization of 13 g L-1 PEF film was achieved by three additions of the LCC in 72 h, while 78% weight loss was obtained using FastPETase in controlled conditions. Nonetheless, 92% weight loss was obtained with FastPETase when using only 6 g L-1 PEF. The main reaction products were identified as FDCA, ethylene glycol, and mono(2-hydroxyethyl)-furanoate. LCC performed better than FastPETase, in terms of both FDCA release and weight loss. The effect of crystallinity was evident on the enzymes' performance, as only 4% to 7% weight loss of crystalline PEF (32%) was recorded. Microscopy studies of the treated PEF films provided information on the surface erosion processes and revealed higher resistance of the crystalline phase, explaining the low level of depolymerization. The study presents important insights into the enzymatic hydrolysis of biobased PEF material and paves the path toward more viable applications within biopolymer waste recycling.
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Affiliation(s)
- Virender Kumar
- Department
of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, 9220 Aalborg, Denmark
| | - Alessandro Pellis
- Dipartimento
di Chimica e Chimica Industriale, Universitá
degli Studi di Genova, Via Dodecaneso 31, Genova 16146, Italy
| | - Reinhard Wimmer
- Department
of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, 9220 Aalborg, Denmark
| | - Vladimir Popok
- Department
of Materials and Production, Aalborg University, Fibigerstræde 16, 9220 Aalborg, Denmark
| | | | - Cristiano Varrone
- Department
of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, 9220 Aalborg, Denmark
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9
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Norton-Baker B, Denton MCR, Murphy NP, Fram B, Lim S, Erickson E, Gauthier NP, Beckham GT. Enabling high-throughput enzyme discovery and engineering with a low-cost, robot-assisted pipeline. Sci Rep 2024; 14:14449. [PMID: 38914665 PMCID: PMC11196671 DOI: 10.1038/s41598-024-64938-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2024] [Accepted: 06/14/2024] [Indexed: 06/26/2024] Open
Abstract
As genomic databases expand and artificial intelligence tools advance, there is a growing demand for efficient characterization of large numbers of proteins. To this end, here we describe a generalizable pipeline for high-throughput protein purification using small-scale expression in E. coli and an affordable liquid-handling robot. This low-cost platform enables the purification of 96 proteins in parallel with minimal waste and is scalable for processing hundreds of proteins weekly per user. We demonstrate the performance of this method with the expression and purification of the leading poly(ethylene terephthalate) hydrolases reported in the literature. Replicate experiments demonstrated reproducibility and enzyme purity and yields (up to 400 µg) sufficient for comprehensive analyses of both thermostability and activity, generating a standardized benchmark dataset for comparing these plastic-degrading enzymes. The cost-effectiveness and ease of implementation of this platform render it broadly applicable to diverse protein characterization challenges in the biological sciences.
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Grants
- DE-SC0022024 U.S. Department of Energy, Office of Science, Office of Biological and Environmental Research (BER), Genomic Science Program
- DE-SC0022024 U.S. Department of Energy, Office of Science, Office of Biological and Environmental Research (BER), Genomic Science Program
- DE-SC0022024 U.S. Department of Energy, Office of Science, Office of Biological and Environmental Research (BER), Genomic Science Program
- DE-SC0022024 U.S. Department of Energy, Office of Science, Office of Biological and Environmental Research (BER), Genomic Science Program
- DE-SC0022024 U.S. Department of Energy, Office of Science, Office of Biological and Environmental Research (BER), Genomic Science Program
- DE-AC36-08GO28308 Advanced Materials and Manufacturing Technologies Office (AMMTO)
- DE-AC36-08GO28308 Advanced Materials and Manufacturing Technologies Office (AMMTO)
- DE-AC36-08GO28308 Advanced Materials and Manufacturing Technologies Office (AMMTO)
- DE-AC36-08GO28308 Advanced Materials and Manufacturing Technologies Office (AMMTO)
- U.S. Department of Energy Office of Energy Efficiency and Renewable Energy Bioenergy Technologies Office (BETO)
- Bio-Optimized Technologies to keep Thermoplastics out of Landfills and the Environment (BOTTLE) Consortium
- Dana-Farber Cancer Institute
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Affiliation(s)
- Brenna Norton-Baker
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, USA
- BOTTLE Consortium, Golden, CO, USA
- Agile BioFoundry, Emeryville, CA, USA
| | - Mackenzie C R Denton
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, USA
- BOTTLE Consortium, Golden, CO, USA
| | - Natasha P Murphy
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, USA
- BOTTLE Consortium, Golden, CO, USA
| | - Benjamin Fram
- Department of Systems Biology, Harvard Medical School, Boston, MA, USA
| | - Samuel Lim
- Department of Systems Biology, Harvard Medical School, Boston, MA, USA
| | - Erika Erickson
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, USA
- BOTTLE Consortium, Golden, CO, USA
| | - Nicholas P Gauthier
- Department of Systems Biology, Harvard Medical School, Boston, MA, USA.
- Department of Data Sciences, Dana-Farber Cancer Institute, Boston, MA, USA.
| | - Gregg T Beckham
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, USA.
- BOTTLE Consortium, Golden, CO, USA.
- Agile BioFoundry, Emeryville, CA, USA.
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10
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Bergeson AR, Silvera AJ, Alper HS. Bottlenecks in biobased approaches to plastic degradation. Nat Commun 2024; 15:4715. [PMID: 38830860 PMCID: PMC11148140 DOI: 10.1038/s41467-024-49146-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Accepted: 05/23/2024] [Indexed: 06/05/2024] Open
Abstract
Plastic waste is an environmental challenge, but also presents a biotechnological opportunity as a unique carbon substrate. With modern biotechnological tools, it is possible to enable both recycling and upcycling. To realize a plastics bioeconomy, significant intrinsic barriers must be overcome using a combination of enzyme, strain, and process engineering. This article highlights advances, challenges, and opportunities for a variety of common plastics.
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Affiliation(s)
- Amelia R Bergeson
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Ashli J Silvera
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, USA
| | - Hal S Alper
- McKetta Department of Chemical Engineering, The University of Texas at Austin, Austin, TX, USA.
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, TX, USA.
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11
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Sahihi M, Fayon P, Nauton L, Goujon F, Devémy J, Dequidt A, Hauret P, Malfreyt P. Probing Enzymatic PET Degradation: Molecular Dynamics Analysis of Cutinase Adsorption and Stability. J Chem Inf Model 2024; 64:4112-4120. [PMID: 38703106 DOI: 10.1021/acs.jcim.4c00079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/06/2024]
Abstract
Understanding the mechanisms influencing poly(ethylene terephthalate) (PET) biodegradation is crucial for developing innovative strategies to accelerate the breakdown of this persistent plastic. In this study, we employed all-atom molecular dynamics simulation to investigate the adsorption process of the LCC-ICCG cutinase enzyme onto the PET surface. Our results revealed that hydrophobic, π-π, and H bond interactions, specifically involving aliphatic, aromatic, and polar uncharged amino acids, were the primary driving forces for the adsorption of the cutinase enzyme onto PET. Additionally, we observed a negligible change in the enzyme's tertiary structure during the interaction with PET (RMSD = 1.35 Å), while its secondary structures remained remarkably stable. Quantitative analysis further demonstrated that there is about a 24% decrease in the number of enzyme-water hydrogen bonds upon adsorption onto the PET surface. The significance of this study lies in unraveling the molecular intricacies of the adsorption process, providing valuable insights into the initial steps of enzymatic PET degradation.
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Affiliation(s)
- Mehdi Sahihi
- Clermont Auvergne INP, CNRS, Institut de Chimie de Clermont-Ferrand, Université Clermont Auvergne, F-63000 Clermont-Ferrand, France
| | - Pierre Fayon
- CHU Clermont Ferrand, Clermont Auvergne INP, CNRS, ICCF, Université Clermont Auvergne, F-63000 Clermont-Ferrand, France
| | - Lionel Nauton
- Clermont Auvergne INP, CNRS, Institut de Chimie de Clermont-Ferrand, Université Clermont Auvergne, F-63000 Clermont-Ferrand, France
| | - Florent Goujon
- Clermont Auvergne INP, CNRS, Institut de Chimie de Clermont-Ferrand, Université Clermont Auvergne, F-63000 Clermont-Ferrand, France
| | - Julien Devémy
- Clermont Auvergne INP, CNRS, Institut de Chimie de Clermont-Ferrand, Université Clermont Auvergne, F-63000 Clermont-Ferrand, France
| | - Alain Dequidt
- Clermont Auvergne INP, CNRS, Institut de Chimie de Clermont-Ferrand, Université Clermont Auvergne, F-63000 Clermont-Ferrand, France
| | - Patrice Hauret
- Manufacture Francaise des Pneumatiques Michelin, 23, Place des Carmes, 63040 Clermont-Ferrand, France
| | - Patrice Malfreyt
- Clermont Auvergne INP, CNRS, Institut de Chimie de Clermont-Ferrand, Université Clermont Auvergne, F-63000 Clermont-Ferrand, France
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12
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Schubert SW, Thomsen TB, Clausen KS, Malmendal A, Hunt CJ, Borch K, Jensen K, Brask J, Meyer AS, Westh P. Relationships of crystallinity and reaction rates for enzymatic degradation of poly (ethylene terephthalate), PET. CHEMSUSCHEM 2024; 17:e202301752. [PMID: 38252197 DOI: 10.1002/cssc.202301752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 01/12/2024] [Accepted: 01/15/2024] [Indexed: 01/23/2024]
Abstract
Biocatalytic degradation of plastic waste is anticipated to play an important role in future recycling systems. However, enzymatic degradation of crystalline poly (ethylene terephthalate) (PET) remains consistently poor. Herein, we employed functional assays to elucidate the molecular underpinnings of this limitation. This included utilizing complementary activity assays to monitor the degradation of PET disks with varying crystallinity (XC), as well as determining enzymatic kinetic parameters for soluble PET fragments. The results indicate that an efficient PET-hydrolase, LCCICCG, operates through an endolytic mode of action, and that its activity is limited by conformational constraints in the PET polymer. Such constraints become more pronounced at high XC values, and this limits the density of productive sites on the PET surface. Endolytic chain-scissions are the dominant reaction type in the initial stage, and this means that little or no soluble organic product are released. However, endolytic cuts gradually and locally promote chain mobility and hence the density of attack sites on the surface. This leads to an upward concave progress curve; a behavior sometimes termed lag-phase kinetics.
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Affiliation(s)
- Sune W Schubert
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, DK-2800, Kgs. Lyngby, Denmark
| | - Thore B Thomsen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, DK-2800, Kgs. Lyngby, Denmark
| | - Kristine S Clausen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, DK-2800, Kgs. Lyngby, Denmark
| | - Anders Malmendal
- Institute of Natural Science and Environmental Chemistry., Roskilde University, Universitetsvej 1, 28 C.1, DK-4000, Roskilde, Denmark
| | - Cameron J Hunt
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, DK-2800, Kgs. Lyngby, Denmark
| | - Kim Borch
- Novozymes A/S, Biologiens Vej 2, DK-2800, Kgs. Lyngby, Denmark
| | - Kenneth Jensen
- Novozymes A/S, Biologiens Vej 2, DK-2800, Kgs. Lyngby, Denmark
| | - Jesper Brask
- Novozymes A/S, Biologiens Vej 2, DK-2800, Kgs. Lyngby, Denmark
| | - Anne S Meyer
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, DK-2800, Kgs. Lyngby, Denmark
| | - Peter Westh
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, DK-2800, Kgs. Lyngby, Denmark
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13
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Liu J, Xin K, Zhang T, Wen Y, Li D, Wei R, Zhou J, Cui Z, Dong W, Jiang M. Identification and characterization of a fungal cutinase-like enzyme CpCut1 from Cladosporium sp. P7 for polyurethane degradation. Appl Environ Microbiol 2024; 90:e0147723. [PMID: 38445906 PMCID: PMC11022569 DOI: 10.1128/aem.01477-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 02/07/2024] [Indexed: 03/07/2024] Open
Abstract
Plastic degradation by biological systems emerges as a prospective avenue for addressing the pressing global concern of plastic waste accumulation. The intricate chemical compositions and diverse structural facets inherent to polyurethanes (PU) substantially increase the complexity associated with PU waste management. Despite the extensive research endeavors spanning over decades, most known enzymes exhibit a propensity for hydrolyzing waterborne PU dispersion (i.e., the commercial Impranil DLN-SD), with only a limited capacity for the degradation of bulky PU materials. Here, we report a novel cutinase (CpCut1) derived from Cladosporium sp. P7, which demonstrates remarkable efficiency in the degrading of various polyester-PU materials. After 12-h incubation at 55°C, CpCut1 was capable of degrading 40.5% and 20.6% of thermoplastic PU film and post-consumer foam, respectively, while achieving complete depolymerization of Impranil DLN-SD. Further analysis of the degradation intermediates suggested that the activity of CpCut1 primarily targeted the ester bonds within the PU soft segments. The versatile performance of CpCut1 against a spectrum of polyester-PU materials positions it as a promising candidate for the bio-recycling of waste plastics.IMPORTANCEPolyurethane (PU) has a complex chemical composition that frequently incorporates a variety of additives, which poses significant obstacles to biodegradability and recyclability. Recent advances have unveiled microbial degradation and enzymatic depolymerization as promising waste PU disposal strategies. In this study, we identified a gene encoding a cutinase from the PU-degrading fungus Cladosporium sp. P7, which allowed the expression, purification, and characterization of the recombinant enzyme CpCut1. Furthermore, this study identified the products derived from the CpCut1 catalyzed PU degradation and proposed its underlying mechanism. These findings highlight the potential of this newly discovered fungal cutinase as a remarkably efficient tool in the degradation of PU materials.
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Affiliation(s)
- Jiawei Liu
- Key Laboratory for Waste Plastics Biocatalytic Degradation and Recycling, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
| | - Kaiyuan Xin
- Key Laboratory for Waste Plastics Biocatalytic Degradation and Recycling, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
| | - Tianyang Zhang
- Key Laboratory for Waste Plastics Biocatalytic Degradation and Recycling, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
| | - Yuan Wen
- Key Laboratory for Waste Plastics Biocatalytic Degradation and Recycling, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
| | - Ding Li
- Institute of Veterinary Immunology & Engineering, Jiangsu Academy of Agricultural Sciences, Nanjing, China
| | - Ren Wei
- Junior Research Group Plastic Biodegradation, Department of Biotechnology and Enzyme Catalysis, Institute of Biochemistry, University of Greifswald, Greifswald, Germany
| | - Jie Zhou
- Key Laboratory for Waste Plastics Biocatalytic Degradation and Recycling, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing, China
| | - Zhongli Cui
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Weiliang Dong
- Key Laboratory for Waste Plastics Biocatalytic Degradation and Recycling, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing, China
| | - Min Jiang
- Key Laboratory for Waste Plastics Biocatalytic Degradation and Recycling, College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing, China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing, China
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14
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Weiland F, Kohlstedt M, Wittmann C. Biobased de novo synthesis, upcycling, and recycling - the heartbeat toward a green and sustainable polyethylene terephthalate industry. Curr Opin Biotechnol 2024; 86:103079. [PMID: 38422776 DOI: 10.1016/j.copbio.2024.103079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 01/19/2024] [Accepted: 01/24/2024] [Indexed: 03/02/2024]
Abstract
Polyethylene terephthalate (PET) has revolutionized the industrial sector because of its versatility, with its predominant uses in the textiles and packaging materials industries. Despite the various advantages of this polymer, its synthesis is, unfavorably, tightly intertwined with nonrenewable fossil resources. Additionally, given its widespread use, accumulating PET waste poses a significant environmental challenge. As a result, current research in the areas of biological recycling, upcycling, and de novo synthesis is intensifying. Biological recycling involves the use of micro-organisms or enzymes to breakdown PET into monomers, offering a sustainable alternative to traditional recycling. Upcycling transforms PET waste into value-added products, expanding its potential application range and promoting a circular economy. Moreover, studies of cascading biological and chemical processes driven by microbial cell factories have explored generating PET using renewable, biobased feedstocks such as lignin. These avenues of research promise to mitigate the environmental footprint of PET, underlining the importance of sustainable innovations in the industry.
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Affiliation(s)
- Fabia Weiland
- Institute of Systems Biotechnology, Saarland University, Germany
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15
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Choi J, Kim H, Ahn YR, Kim M, Yu S, Kim N, Lim SY, Park JA, Ha SJ, Lim KS, Kim HO. Recent advances in microbial and enzymatic engineering for the biodegradation of micro- and nanoplastics. RSC Adv 2024; 14:9943-9966. [PMID: 38528920 PMCID: PMC10961967 DOI: 10.1039/d4ra00844h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 03/19/2024] [Indexed: 03/27/2024] Open
Abstract
This review examines the escalating issue of plastic pollution, specifically highlighting the detrimental effects on the environment and human health caused by microplastics and nanoplastics. The extensive use of synthetic polymers such as polyethylene (PE), polyethylene terephthalate (PET), and polystyrene (PS) has raised significant environmental concerns because of their long-lasting and non-degradable characteristics. This review delves into the role of enzymatic and microbial strategies in breaking down these polymers, showcasing recent advancements in the field. The intricacies of enzymatic degradation are thoroughly examined, including the effectiveness of enzymes such as PETase and MHETase, as well as the contribution of microbial pathways in breaking down resilient polymers into more benign substances. The paper also discusses the impact of chemical composition on plastic degradation kinetics and emphasizes the need for an approach to managing the environmental impact of synthetic polymers. The review highlights the significance of comprehending the physical characteristics and long-term impacts of micro- and nanoplastics in different ecosystems. Furthermore, it points out the environmental and health consequences of these contaminants, such as their ability to cause cancer and interfere with the endocrine system. The paper emphasizes the need for advanced analytical methods and effective strategies for enzymatic degradation, as well as continued research and development in this area. This review highlights the crucial role of enzymatic and microbial strategies in addressing plastic pollution and proposes methods to create effective and environmentally friendly solutions.
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Affiliation(s)
- Jaewon Choi
- Division of Chemical Engineering and Bioengineering, College of Art, Culture and Engineering, Kangwon National University Chuncheon Korea
- Department of Smart Health Science and Technology, Kangwon National University Chuncheon Korea
| | - Hongbin Kim
- Division of Chemical Engineering and Bioengineering, College of Art, Culture and Engineering, Kangwon National University Chuncheon Korea
- Department of Smart Health Science and Technology, Kangwon National University Chuncheon Korea
| | - Yu-Rim Ahn
- Division of Chemical Engineering and Bioengineering, College of Art, Culture and Engineering, Kangwon National University Chuncheon Korea
- Department of Smart Health Science and Technology, Kangwon National University Chuncheon Korea
| | - Minse Kim
- Division of Chemical Engineering and Bioengineering, College of Art, Culture and Engineering, Kangwon National University Chuncheon Korea
- Department of Smart Health Science and Technology, Kangwon National University Chuncheon Korea
| | - Seona Yu
- Division of Chemical Engineering and Bioengineering, College of Art, Culture and Engineering, Kangwon National University Chuncheon Korea
- Department of Smart Health Science and Technology, Kangwon National University Chuncheon Korea
| | - Nanhyeon Kim
- Division of Chemical Engineering and Bioengineering, College of Art, Culture and Engineering, Kangwon National University Chuncheon Korea
- Department of Smart Health Science and Technology, Kangwon National University Chuncheon Korea
| | - Su Yeon Lim
- Division of Chemical Engineering and Bioengineering, College of Art, Culture and Engineering, Kangwon National University Chuncheon Korea
- Department of Smart Health Science and Technology, Kangwon National University Chuncheon Korea
| | - Jeong-Ann Park
- Department of Environmental Engineering, Kangwon National University Chuncheon 24341 Republic of Korea
| | - Suk-Jin Ha
- Division of Chemical Engineering and Bioengineering, College of Art, Culture and Engineering, Kangwon National University Chuncheon Korea
- Department of Smart Health Science and Technology, Kangwon National University Chuncheon Korea
| | - Kwang Suk Lim
- Division of Chemical Engineering and Bioengineering, College of Art, Culture and Engineering, Kangwon National University Chuncheon Korea
- Department of Smart Health Science and Technology, Kangwon National University Chuncheon Korea
| | - Hyun-Ouk Kim
- Division of Chemical Engineering and Bioengineering, College of Art, Culture and Engineering, Kangwon National University Chuncheon Korea
- Department of Smart Health Science and Technology, Kangwon National University Chuncheon Korea
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16
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Cui Y, Chen Y, Sun J, Zhu T, Pang H, Li C, Geng WC, Wu B. Computational redesign of a hydrolase for nearly complete PET depolymerization at industrially relevant high-solids loading. Nat Commun 2024; 15:1417. [PMID: 38360963 PMCID: PMC10869840 DOI: 10.1038/s41467-024-45662-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 01/30/2024] [Indexed: 02/17/2024] Open
Abstract
Biotechnological plastic recycling has emerged as a suitable option for addressing the pollution crisis. A major breakthrough in the biodegradation of poly(ethylene terephthalate) (PET) is achieved by using a LCC variant, which permits 90% conversion at an industrial level. Despite the achievements, its applications have been hampered by the remaining 10% of nonbiodegradable PET. Herein, we address current challenges by employing a computational strategy to engineer a hydrolase from the bacterium HR29. The redesigned variant, TurboPETase, outperforms other well-known PET hydrolases. Nearly complete depolymerization is accomplished in 8 h at a solids loading of 200 g kg-1. Kinetic and structural analysis suggest that the improved performance may be attributed to a more flexible PET-binding groove that facilitates the targeting of more specific attack sites. Collectively, our results constitute a significant advance in understanding and engineering of industrially applicable polyester hydrolases, and provide guidance for further efforts on other polymer types.
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Affiliation(s)
- Yinglu Cui
- AIM Center, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
| | - Yanchun Chen
- AIM Center, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Jinyuan Sun
- AIM Center, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Tong Zhu
- AIM Center, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Hua Pang
- AIM Center, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Chunli Li
- AIM Center, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Wen-Chao Geng
- AIM Center, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- College of Chemistry, Nankai University, Tianjin, China
| | - Bian Wu
- AIM Center, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
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17
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Yang Y, Cheng S, Zheng Y, Xue T, Huang JW, Zhang L, Yang Y, Guo RT, Chen CC. Remodeling the polymer-binding cavity to improve the efficacy of PBAT-degrading enzyme. JOURNAL OF HAZARDOUS MATERIALS 2024; 464:132965. [PMID: 37979420 DOI: 10.1016/j.jhazmat.2023.132965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 10/31/2023] [Accepted: 11/07/2023] [Indexed: 11/20/2023]
Abstract
Poly(butylene adipate-co-terephthalate) (PBAT) is among the most widely applied synthetic polyesters that are utilized in the packaging and agricultural industries, but the accumulation of PBAT wastes has posed a great burden to ecosystems. Using renewable enzymes to decompose PBAT is an eco-friendly solution to tackle this problem. Recently, we demonstrated that cutinase is the most effective PBAT-degrading enzyme and that an engineered cutinase termed TfCut-DM could completely decompose PBAT film to terephthalate (TPA). Here, we report crystal structures of a variant of leaf compost cutinase in complex with soluble fragments of PBAT, including BTa and TaBTa. In the TaBTa complex, one TPA moiety was located at a polymer-binding site distal to the catalytic center that has never been experimentally validated. Intriguingly, the composition of the distal TPA-binding site shows higher diversity relative to the one proximal to the catalytic center in various cutinases. We thus modified the distal TPA-binding site of TfCut-DM and obtained variants that exhibit higher activity. Notably, the time needed to completely degrade the PBAT film to TPA was shortened to within 24 h by TfCut-DM Q132Y (5813 mol per mol protein). Taken together, the structural information regarding the substrate-binding behavior of PBAT-degrading enzymes could be useful guidance for direct enzyme engineering.
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Affiliation(s)
- Yu Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, 430062 Wuhan, People's Republic of China
| | - Shujing Cheng
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, 430062 Wuhan, People's Republic of China
| | - Yingyu Zheng
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, 430062 Wuhan, People's Republic of China
| | - Ting Xue
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, 430062 Wuhan, People's Republic of China
| | - Jian-Wen Huang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, 430062 Wuhan, People's Republic of China
| | - Lilan Zhang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, 430062 Wuhan, People's Republic of China
| | - Yunyun Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, 430062 Wuhan, People's Republic of China
| | - Rey-Ting Guo
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, 430062 Wuhan, People's Republic of China; Department of Immunology and Pathogen Biology, School of Basic Medical Sciences, Hangzhou Normal University, 311121 Hangzhou, People's Republic of China.
| | - Chun-Chi Chen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Hubei Hongshan Laboratory, Hubei Collaborative Innovation Center for Green Transformation of Bio-Resources, Hubei Key Laboratory of Industrial Biotechnology, School of Life Sciences, Hubei University, 430062 Wuhan, People's Republic of China; Department of Immunology and Pathogen Biology, School of Basic Medical Sciences, Hangzhou Normal University, 311121 Hangzhou, People's Republic of China.
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18
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Joho Y, Vongsouthi V, Gomez C, Larsen JS, Ardevol A, Jackson CJ. Improving plastic degrading enzymes via directed evolution. Protein Eng Des Sel 2024; 37:gzae009. [PMID: 38713696 PMCID: PMC11091475 DOI: 10.1093/protein/gzae009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 04/30/2024] [Accepted: 05/05/2024] [Indexed: 05/09/2024] Open
Abstract
Plastic degrading enzymes have immense potential for use in industrial applications. Protein engineering efforts over the last decade have resulted in considerable enhancement of many properties of these enzymes. Directed evolution, a protein engineering approach that mimics the natural process of evolution in a laboratory, has been particularly useful in overcoming some of the challenges of structure-based protein engineering. For example, directed evolution has been used to improve the catalytic activity and thermostability of polyethylene terephthalate (PET)-degrading enzymes, although its use for the improvement of other desirable properties, such as solvent tolerance, has been less studied. In this review, we aim to identify some of the knowledge gaps and current challenges, and highlight recent studies related to the directed evolution of plastic-degrading enzymes.
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Affiliation(s)
- Yvonne Joho
- Manufacturing, Commonwealth Scientific and Industrial Research Organisation, Research Way, Clayton, Victoria 3168, Australia
- Research School of Chemistry, Australian National University, Sullivans Creek Rd, Canberra, ACT 2601, Australia
- CSIRO Advanced Engineering Biology Future Science Platform, GPO Box 1700, Canberra, ACT 2601, Australia
| | - Vanessa Vongsouthi
- Research School of Chemistry, Australian National University, Sullivans Creek Rd, Canberra, ACT 2601, Australia
| | - Chloe Gomez
- Research School of Chemistry, Australian National University, Sullivans Creek Rd, Canberra, ACT 2601, Australia
| | - Joachim S Larsen
- Research School of Chemistry, Australian National University, Sullivans Creek Rd, Canberra, ACT 2601, Australia
- ARC Centre of Excellence for Synthetic Biology, Research School of Chemistry, Australian National University, Sullivans Creek Rd, Canberra, ACT 2601, Australia
| | - Albert Ardevol
- Manufacturing, Commonwealth Scientific and Industrial Research Organisation, Research Way, Clayton, Victoria 3168, Australia
- CSIRO Advanced Engineering Biology Future Science Platform, GPO Box 1700, Canberra, ACT 2601, Australia
| | - Colin J Jackson
- Research School of Chemistry, Australian National University, Sullivans Creek Rd, Canberra, ACT 2601, Australia
- ARC Centre of Excellence for Synthetic Biology, Research School of Chemistry, Australian National University, Sullivans Creek Rd, Canberra, ACT 2601, Australia
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Sullivans Creek Rd, Canberra, ACT 2601, Australia
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19
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Shi L, Zhu L. Recent Advances and Challenges in Enzymatic Depolymerization and Recycling of PET Wastes. Chembiochem 2024; 25:e202300578. [PMID: 37960968 DOI: 10.1002/cbic.202300578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 11/12/2023] [Accepted: 11/13/2023] [Indexed: 11/15/2023]
Abstract
Poly (ethylene terephthalate) (PET) is one of the most commonly used plastics in daily life and various industries. Enzymatic depolymerization and recycling of post-consumer PET (pc-PET) provides a promising strategy for the sustainable circular economy of polymers. Great protein engineering efforts have been devoted to improving the depolymerization performance of PET hydrolytic enzymes (PHEs). In this review, we first discuss the mechanisms and challenges of enzymatic PET depolymerization. Subsequently, we summarize the state-of-the-art engineering of PHEs including rational design, machine learning, and directed evolution for improved depolymerization performance, and highlight the advances in screening methods of PHEs. We further discuss several factors that affect the enzymatic depolymerization efficiency. We conclude with our perspective on the opportunities and challenges in bio-recycling and bio-upcycling of PET wastes.
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Affiliation(s)
- Lixia Shi
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, China
- National Technology Innovation Center of Synthetic Biology, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, China
| | - Leilei Zhu
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, China
- National Technology Innovation Center of Synthetic Biology, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, China
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20
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Xue R, Qiu C, Zhou X, Cheng Y, Zhang Z, Zhang Y, Schröder U, Bornscheuer UT, Dong W, Wei R, Jiang M. Enzymatic Upcycling of PET Waste to Calcium Terephthalate for Battery Anodes. Angew Chem Int Ed Engl 2024; 63:e202313633. [PMID: 37880836 DOI: 10.1002/anie.202313633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 10/23/2023] [Accepted: 10/25/2023] [Indexed: 10/27/2023]
Abstract
Biotechnological recycling offers a promising solution to address the environmental concerns associated with waste plastics, particularly polyethylene terephthalate (PET), widely utilized in packaging materials and textiles. To advance the development of a bio-based circular plastic economy, innovative upcycling strategies capable of generating higher-value products are needed. In this study, we enhanced the enzymatic depolymerization of waste PET by incorporating highly concentrated calcium ions (up to 1 m) to the hydrolytic reaction catalyzed by the best currently known enzyme LCCICCG . The presence of calcium ions not only improved the thermal stability and activity of the biocatalyst but also significantly reduced the consumption of base required to maintain optimal pH levels. Employing optimized conditions at 80 °C for 12 h, we successfully converted ≈84 % of the waste PET (200 g L-1 ) into solid hydrated calcium terephthalate (CaTP ⋅ 3H2 O) as the primary product instead of soluble terephthalate salt. CaTP ⋅ 3H2 O was easily purified and employed as a raw material for battery electrode production, exhibiting an initial reversible specific capacity of 164.2 mAh g-1 . Through techno-economic analysis, we conclusively demonstrated that the one-pot biocatalysis-based synthesis of CaTP is a superior PET upcycling strategy than the secondary synthesis method employing recycled terephthalic acid.
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Affiliation(s)
- Rui Xue
- College of Biotechnology and Pharmaceutical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing, 211816, P. R. China
| | - Canhao Qiu
- College of Biotechnology and Pharmaceutical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing, 211816, P. R. China
| | - Xiaoli Zhou
- College of Biotechnology and Pharmaceutical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing, 211816, P. R. China
| | - Yun Cheng
- College of Biotechnology and Pharmaceutical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing, 211816, P. R. China
| | - Zhen Zhang
- School of Energy Science and Engineering, Nanjing Tech University, Nanjing, 211816, P. R. China
| | - Yi Zhang
- School of Energy Science and Engineering, Nanjing Tech University, Nanjing, 211816, P. R. China
| | - Uwe Schröder
- Institute of Biochemistry, University of Greifswald, Felix-Hausdorff-Str. 4, 17487, Greifswald, Germany
| | - Uwe T Bornscheuer
- Institute of Biochemistry, University of Greifswald, Felix-Hausdorff-Str. 4, 17487, Greifswald, Germany
| | - Weiliang Dong
- College of Biotechnology and Pharmaceutical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing, 211816, P. R. China
| | - Ren Wei
- Institute of Biochemistry, University of Greifswald, Felix-Hausdorff-Str. 4, 17487, Greifswald, Germany
| | - Min Jiang
- College of Biotechnology and Pharmaceutical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing, 211816, P. R. China
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21
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Qiu J, Chen Y, Zhang L, Wu J, Zeng X, Shi X, Liu L, Chen J. A comprehensive review on enzymatic biodegradation of polyethylene terephthalate. ENVIRONMENTAL RESEARCH 2024; 240:117427. [PMID: 37865324 DOI: 10.1016/j.envres.2023.117427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 10/11/2023] [Accepted: 10/15/2023] [Indexed: 10/23/2023]
Abstract
Polyethylene terephthalate (PET) is a polymer synthesized via the dehydration and condensation reaction between ethylene glycol and terephthalic acid. PET has emerged as one of the most extensively employed plastic materials due to its exceptional plasticity and durability. Nevertheless, PET has a complex structure and is extremely difficult to degrade in nature, causing severe pollution to the global ecological environment and posing a threat to human health. Currently, the methods for PET processing mainly include physical, chemical, and biological methods. Biological enzyme degradation is considered the most promising PET degradation method. In recent years, an increasing number of enzymes that can degrade PET have been identified, and they primarily target the ester bond of PET. This review comprehensively introduced the latest research progress in PET enzymatic degradation from the aspects of PET-degrading enzymes, PET biodegradation pathways, the catalytic mechanism of PET-degrading enzymes, and biotechnological strategies for enhancing PET-degrading enzymes. On this basis, the current challenges within the enzymatic PET degradation process were summarized, and the directions that need to be worked on in the future were pointed out. This review provides a reference and basis for the subsequent effective research on PET biodegradation.
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Affiliation(s)
- Jiarong Qiu
- School of Advanced Manufacturing, Fuzhou University, Jinjiang 362251, China; Development Center of Science and Education Park of Fuzhou University, Jinjiang, 362251, China
| | - Yuxin Chen
- School of Advanced Manufacturing, Fuzhou University, Jinjiang 362251, China
| | - Liangqing Zhang
- School of Advanced Manufacturing, Fuzhou University, Jinjiang 362251, China; Development Center of Science and Education Park of Fuzhou University, Jinjiang, 362251, China.
| | - Jinzhi Wu
- School of Advanced Manufacturing, Fuzhou University, Jinjiang 362251, China
| | - Xianhai Zeng
- College of Energy, Xiamen University, Xiamen 361102, China
| | - Xinguo Shi
- School of Advanced Manufacturing, Fuzhou University, Jinjiang 362251, China
| | - Lemian Liu
- School of Advanced Manufacturing, Fuzhou University, Jinjiang 362251, China
| | - Jianfeng Chen
- School of Advanced Manufacturing, Fuzhou University, Jinjiang 362251, China
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22
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Thomsen TB, Almdal K, Meyer AS. Significance of poly(ethylene terephthalate) (PET) substrate crystallinity on enzymatic degradation. N Biotechnol 2023; 78:162-172. [PMID: 37939899 DOI: 10.1016/j.nbt.2023.11.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Revised: 10/20/2023] [Accepted: 11/04/2023] [Indexed: 11/10/2023]
Abstract
Poly(ethylene terephthalate) (PET) is a semi-crystalline plastic polyester material with a global production volume of 83 Mt/year. PET is mainly used in textiles, but also widely used for packaging materials, notably plastic bottles, and is a major contributor to environmental plastic waste accumulation. Now that enzymes have been demonstrated to catalyze PET degradation, new options for sustainable bio-recycling of PET materials via enzymatic catalysis have emerged. The enzymatic degradation rate is strongly influenced by the properties of PET, notably the degree of crystallinity, XC. The higher the XC of the PET material, the slower the enzymatic rate. Crystallization of PET, resulting in increased XC, is induced thermally (via heating) and/or mechanically (via stretching), and the XC of most PET plastic bottles and microplastics exceeds what currently known enzymes can readily degrade. The enzymatic action occurs at the surface of the insoluble PET material and improves when the polyester chain mobility increases. The chain mobility increases drastically when the temperature exceeds the glass transition temperature, Tg, which is ∼40 °C at the surface layer of PET. Since PET crystallization starts at 70 °C, the ideal temperature for enzymatic degradation is just below 70 °C to balance high chain mobility and enzymatic reaction activation without inducing crystal formation. This paper reviews the current understanding on the properties of PET as an enzyme substrate and summarizes the most recent knowledge of how the crystalline and amorphous regions of PET form, and how the XC and the Tg impact the efficiency of enzymatic PET degradation.
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Affiliation(s)
- Thore Bach Thomsen
- Department of Biotechnology and Biomedicine, DTU Bioengineering, Protein Chemistry and Enzyme Technology Section, Building 221, Technical University of Denmark, 2800 Kgs Lyngby, Denmark
| | - Kristoffer Almdal
- DTU Chemistry, Building 206, Technical University of Denmark, 2800 Kgs Lyngby, Denmark
| | - Anne S Meyer
- Department of Biotechnology and Biomedicine, DTU Bioengineering, Protein Chemistry and Enzyme Technology Section, Building 221, Technical University of Denmark, 2800 Kgs Lyngby, Denmark.
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23
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Cribari MA, Unger MJ, Unarta IC, Ogorek AN, Huang X, Martell JD. Ultrahigh-Throughput Directed Evolution of Polymer-Degrading Enzymes Using Yeast Display. J Am Chem Soc 2023; 145:27380-27389. [PMID: 38051911 PMCID: PMC11058326 DOI: 10.1021/jacs.3c08291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2023]
Abstract
Enzymes that degrade synthetic polymers have attracted intense interest for eco-friendly plastic recycling. However, because enzymes did not evolve for the cleavage of abiotic polymers, directed evolution strategies are needed to enhance activity for plastic degradation. Previous directed evolution efforts relied on polymer degradation assays that were limited to screening ∼104 mutants. Here, we report a high-throughput yeast surface display platform to rapidly evaluate >107 enzyme mutants for increased activity in cleaving synthetic polymers. In this platform, individual yeast cells display distinct mutants, and enzyme activity is detected by a change in fluorescence upon the cleavage of a synthetic probe resembling a polymer of interest. Highly active mutants are isolated by fluorescence activated cell sorting and identified through DNA sequencing. To demonstrate this platform, we performed directed evolution of a polyethylene terephthalate (PET)-depolymerizing enzyme, leaf and branch compost cutinase (LCC). We identified activity-boosting mutations that substantially increased the kinetics of degradation of solid PET films. Biochemical assays and molecular dynamics (MD) simulations of the most active variants suggest that the H218Y mutation improves the binding of the enzyme to PET. Overall, this evolution platform increases the screening throughput of polymer-degrading enzymes by 3 orders of magnitude and identifies mutations that enhance kinetics for depolymerizing solid substrates.
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Affiliation(s)
- Mario A. Cribari
- Department of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | - Maxwell J. Unger
- Department of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | - Ilona C. Unarta
- Department of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
- Theoretical Chemistry Institute, Department of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | - Ashley N. Ogorek
- Department of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | - Xuhui Huang
- Department of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
- Theoretical Chemistry Institute, Department of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | - Jeffrey D. Martell
- Department of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
- Carbone Cancer Center, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53705, United States
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24
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Arnal G, Anglade J, Gavalda S, Tournier V, Chabot N, Bornscheuer UT, Weber G, Marty A. Assessment of Four Engineered PET Degrading Enzymes Considering Large-Scale Industrial Applications. ACS Catal 2023; 13:13156-13166. [PMID: 37881793 PMCID: PMC10594578 DOI: 10.1021/acscatal.3c02922] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 09/13/2023] [Indexed: 10/27/2023]
Abstract
In recent years, enzymatic recycling of the widely used polyester polyethylene terephthalate (PET) has become a complementary solution to current thermomechanical recycling for colored, opaque, and mixed PET. A large set of promising hydrolases that depolymerize PET have been found and enhanced by worldwide initiatives using various methods of protein engineering. Despite the achievements made in these works, it remains difficult to compare enzymes' performance and their applicability to large-scale reactions due to a lack of homogeneity between the experimental protocols used. Here, we pave the way for a standardized enzymatic PET hydrolysis protocol using reaction conditions relevant for larger scale hydrolysis and apply these parameters to four recently reported PET hydrolases (LCCICCG, FAST-PETase, HotPETase, and PES-H1L92F/Q94Y). We show that FAST-PETase and HotPETase have intrinsic limitations that may not permit their application on larger reaction scales, mainly due to their relatively low depolymerization rates. With 80% PET depolymerization, PES-H1L92F/Q94Y may be a suitable candidate for industrial reaction scales upon further rounds of enzyme evolution. LCCICCG outperforms the other enzymes, converting 98% of PET into the monomeric products terephthalic acid (TPA) and ethylene glycol (EG) in 24 h. In addition, we optimized the reaction conditions of LCCICCG toward economic viability, reducing the required amount of enzyme by a factor of 3 and the temperature of the reaction from 72 to 68 °C. We anticipate our findings to advance enzymatic PET hydrolysis toward a coherent assessment of the enzymes and materialize feasibility at larger reaction scales.
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Affiliation(s)
- Grégory Arnal
- Carbios, Parc Cataroux—Bâtiment
B80, 8 Rue de la Grolière, 63100 Clermont-Ferrand, France
| | - Julien Anglade
- Toulouse
Biotechnology Institute, TBI, Université
de Toulouse, CNRS, INRAE, INSA, 135 Avenue de Rangueil, 31077 Toulouse Cedex 4, France
| | - Sabine Gavalda
- Carbios, Parc Cataroux—Bâtiment
B80, 8 Rue de la Grolière, 63100 Clermont-Ferrand, France
| | - Vincent Tournier
- Carbios, Parc Cataroux—Bâtiment
B80, 8 Rue de la Grolière, 63100 Clermont-Ferrand, France
| | - Nicolas Chabot
- Carbios, Parc Cataroux—Bâtiment
B80, 8 Rue de la Grolière, 63100 Clermont-Ferrand, France
| | - Uwe T. Bornscheuer
- Institute
of Biochemistry, Biotechnology & Enzyme Catalysis, University of Greifswald, Felix-Hausdorff-Str. 4, 17487 Greifswald, Germany
| | - Gert Weber
- Macromolecular
Crystallography, Helmholtz-Zentrum Berlin
für Materialien und Energie, Albert-Einstein-Straße 15, 12489 Berlin, Germany
| | - Alain Marty
- Carbios, Parc Cataroux—Bâtiment
B80, 8 Rue de la Grolière, 63100 Clermont-Ferrand, France
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25
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Sui B, Wang T, Fang J, Hou Z, Shu T, Lu Z, Liu F, Zhu Y. Recent advances in the biodegradation of polyethylene terephthalate with cutinase-like enzymes. Front Microbiol 2023; 14:1265139. [PMID: 37849919 PMCID: PMC10577388 DOI: 10.3389/fmicb.2023.1265139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2023] [Accepted: 09/15/2023] [Indexed: 10/19/2023] Open
Abstract
Polyethylene terephthalate (PET) is a synthetic polymer in the polyester family. It is widely found in objects used daily, including packaging materials (such as bottles and containers), textiles (such as fibers), and even in the automotive and electronics industries. PET is known for its excellent mechanical properties, chemical resistance, and transparency. However, these features (e.g., high hydrophobicity and high molecular weight) also make PET highly resistant to degradation by wild-type microorganisms or physicochemical methods in nature, contributing to the accumulation of plastic waste in the environment. Therefore, accelerated PET recycling is becoming increasingly urgent to address the global environmental problem caused by plastic wastes and prevent plastic pollution. In addition to traditional physical cycling (e.g., pyrolysis, gasification) and chemical cycling (e.g., chemical depolymerization), biodegradation can be used, which involves breaking down organic materials into simpler compounds by microorganisms or PET-degrading enzymes. Lipases and cutinases are the two classes of enzymes that have been studied extensively for this purpose. Biodegradation of PET is an attractive approach for managing PET waste, as it can help reduce environmental pollution and promote a circular economy. During the past few years, great advances have been accomplished in PET biodegradation. In this review, current knowledge on cutinase-like PET hydrolases (such as TfCut2, Cut190, HiC, and LCC) was described in detail, including the structures, ligand-protein interactions, and rational protein engineering for improved PET-degrading performance. In particular, applications of the engineered catalysts were highlighted, such as improving the PET hydrolytic activity by constructing fusion proteins. The review is expected to provide novel insights for the biodegradation of complex polymers.
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Affiliation(s)
- Beibei Sui
- School of Biological Science, Jining Medical University, Jining, Shandong, China
| | - Tao Wang
- School of Biological Science, Jining Medical University, Jining, Shandong, China
| | - Jingxiang Fang
- Rizhao Administration for Market Regulation, Rizhao, Shandong, China
| | - Zuoxuan Hou
- School of Biological Science, Jining Medical University, Jining, Shandong, China
| | - Ting Shu
- School of Biological Science, Jining Medical University, Jining, Shandong, China
| | - Zhenhua Lu
- College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, Zhejiang, China
| | - Fei Liu
- School of Biological Science, Jining Medical University, Jining, Shandong, China
| | - Youshuang Zhu
- School of Biological Science, Jining Medical University, Jining, Shandong, China
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26
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Williams GB, Ma H, Khusnutdinova AN, Yakunin AF, Golyshin PN. Harnessing extremophilic carboxylesterases for applications in polyester depolymerisation and plastic waste recycling. Essays Biochem 2023; 67:715-729. [PMID: 37334661 PMCID: PMC10423841 DOI: 10.1042/ebc20220255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Revised: 06/01/2023] [Accepted: 06/05/2023] [Indexed: 06/20/2023]
Abstract
The steady growth in industrial production of synthetic plastics and their limited recycling have resulted in severe environmental pollution and contribute to global warming and oil depletion. Currently, there is an urgent need to develop efficient plastic recycling technologies to prevent further environmental pollution and recover chemical feedstocks for polymer re-synthesis and upcycling in a circular economy. Enzymatic depolymerization of synthetic polyesters by microbial carboxylesterases provides an attractive addition to existing mechanical and chemical recycling technologies due to enzyme specificity, low energy consumption, and mild reaction conditions. Carboxylesterases constitute a diverse group of serine-dependent hydrolases catalysing the cleavage and formation of ester bonds. However, the stability and hydrolytic activity of identified natural esterases towards synthetic polyesters are usually insufficient for applications in industrial polyester recycling. This necessitates further efforts on the discovery of robust enzymes, as well as protein engineering of natural enzymes for enhanced activity and stability. In this essay, we discuss the current knowledge of microbial carboxylesterases that degrade polyesters (polyesterases) with focus on polyethylene terephthalate (PET), which is one of the five major synthetic polymers. Then, we briefly review the recent progress in the discovery and protein engineering of microbial polyesterases, as well as developing enzyme cocktails and secreted protein expression for applications in the depolymerisation of polyester blends and mixed plastics. Future research aimed at the discovery of novel polyesterases from extreme environments and protein engineering for improved performance will aid developing efficient polyester recycling technologies for the circular plastics economy.
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Affiliation(s)
- Gwion B Williams
- Centre for Environmental Biotechnology, School of Natural Sciences, Bangor University, Deiniol Road, Bangor LL57 2UW, U.K
| | - Hairong Ma
- Centre for Environmental Biotechnology, School of Natural Sciences, Bangor University, Deiniol Road, Bangor LL57 2UW, U.K
| | - Anna N Khusnutdinova
- Centre for Environmental Biotechnology, School of Natural Sciences, Bangor University, Deiniol Road, Bangor LL57 2UW, U.K
| | - Alexander F Yakunin
- Centre for Environmental Biotechnology, School of Natural Sciences, Bangor University, Deiniol Road, Bangor LL57 2UW, U.K
| | - Peter N Golyshin
- Centre for Environmental Biotechnology, School of Natural Sciences, Bangor University, Deiniol Road, Bangor LL57 2UW, U.K
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27
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Jayasekara SK, Joni HD, Jayantha B, Dissanayake L, Mandrell C, Sinharage MM, Molitor R, Jayasekara T, Sivakumar P, Jayakody LN. Trends in in-silico guided engineering of efficient polyethylene terephthalate (PET) hydrolyzing enzymes to enable bio-recycling and upcycling of PET. Comput Struct Biotechnol J 2023; 21:3513-3521. [PMID: 37484494 PMCID: PMC10362282 DOI: 10.1016/j.csbj.2023.06.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 06/01/2023] [Accepted: 06/03/2023] [Indexed: 07/25/2023] Open
Abstract
Polyethylene terephthalate (PET) is the largest produced polyester globally, and less than 30% of all the PET produced globally (∼6 billion pounds annually) is currently recycled into lower-quality products. The major drawbacks in current recycling methods (mechanical and chemical), have inspired the exploration of potentially efficient and sustainable PET depolymerization using biological approaches. Researchers have discovered efficient PET hydrolyzing enzymes in the plastisphere and have demonstrated the selective degradation of PET to original monomers thus enabling biological recycling or upcycling. However, several significant hurdles such as the less efficiency of the hydrolytic reaction, low thermostability of the enzymes, and the inability of the enzyme to depolymerize crystalline PET must be addressed in order to establish techno-economically feasible commercial-scale biological PET recycling or upcycling processes. Researchers leverage a synthetic biology-based design; build, test, and learn (DBTL) methodology to develop commercially applicable efficient PET hydrolyzing enzymes through 1) high-throughput metagenomic and proteomic approaches to discover new PET hydrolyzing enzymes with superior properties: and, 2) enzyme engineering approaches to modify and optimize PET hydrolyzing properties. Recently, in-silico platforms including molecular mechanics and machine learning concepts are emerging as innovative tools for the development of more efficient and effective PET recycling through the exploration of novel mutations in PET hydrolyzing enzymes. In-silico-guided PET hydrolyzing enzyme engineering with DBTL cycles enables the rapid development of efficient variants of enzymes over tedious conventional enzyme engineering methods such as random or directed evolution. This review highlights the potential of in-silico-guided PET degrading enzyme engineering to create more efficient variants, including Ideonella sakaiensis PETase (IsPETase) and leaf-branch compost cutinases (LCC). Furthermore, future research prospects are discussed to enable a sustainable circular economy through the bioconversion of PET to original or high-value platform chemicals.
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Affiliation(s)
- Sandhya K. Jayasekara
- School of Biological Science, Southern Illinois University Carbondale, Carbondale, IL, USA
| | - Hriday Dhar Joni
- School of Physics and Applied Physics, Southern Illinois University Carbondale, Carbondale, IL, USA
| | - Bhagya Jayantha
- School of Biological Science, Southern Illinois University Carbondale, Carbondale, IL, USA
| | - Lakshika Dissanayake
- School of Biological Science, Southern Illinois University Carbondale, Carbondale, IL, USA
| | - Christopher Mandrell
- School of Physics and Applied Physics, Southern Illinois University Carbondale, Carbondale, IL, USA
| | - Manuka M.S. Sinharage
- School of Physics and Applied Physics, Southern Illinois University Carbondale, Carbondale, IL, USA
| | - Ryan Molitor
- School of Physics and Applied Physics, Southern Illinois University Carbondale, Carbondale, IL, USA
| | - Thushari Jayasekara
- School of Physics and Applied Physics, Southern Illinois University Carbondale, Carbondale, IL, USA
| | - Poopalasingam Sivakumar
- School of Physics and Applied Physics, Southern Illinois University Carbondale, Carbondale, IL, USA
| | - Lahiru N. Jayakody
- School of Biological Science, Southern Illinois University Carbondale, Carbondale, IL, USA
- Fermentation Science Institute, Southern Illinois University Carbondale, Carbondale, IL, USA
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28
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Carr CM, Keller MB, Paul B, Schubert SW, Clausen KSR, Jensen K, Clarke DJ, Westh P, Dobson ADW. Purification and biochemical characterization of SM14est, a PET-hydrolyzing enzyme from the marine sponge-derived Streptomyces sp. SM14. Front Microbiol 2023; 14:1170880. [PMID: 37250061 PMCID: PMC10213408 DOI: 10.3389/fmicb.2023.1170880] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Accepted: 04/21/2023] [Indexed: 05/31/2023] Open
Abstract
The successful enzymatic degradation of polyester substrates has fueled worldwide investigation into the treatment of plastic waste using bio-based processes. Within this realm, marine-associated microorganisms have emerged as a promising source of polyester-degrading enzymes. In this work, we describe the hydrolysis of the synthetic polymer PET by SM14est, a polyesterase which was previously identified from Streptomyces sp. SM14, an isolate of the marine sponge Haliclona simulans. The PET hydrolase activity of purified SM14est was assessed using a suspension-based assay and subsequent analysis of reaction products by UV-spectrophotometry and RP-HPLC. SM14est displayed a preference for high salt conditions, with activity significantly increasing at sodium chloride concentrations from 100 mM up to 1,000 mM. The initial rate of PET hydrolysis by SM14est was determined to be 0.004 s-1 at 45°C, which was increased by 5-fold to 0.02 s-1 upon addition of 500 mM sodium chloride. Sequence alignment and structural comparison with known PET hydrolases, including the marine halophile PET6, and the highly efficient, thermophilic PHL7, revealed conserved features of interest. Based on this work, SM14est emerges as a useful enzyme that is more similar to key players in the area of PET hydrolysis, like PHL7 and IsPETase, than it is to its marine counterparts. Salt-tolerant polyesterases such as SM14est are potentially valuable in the biological degradation of plastic particles that readily contaminate marine ecosystems and industrial wastewaters.
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Affiliation(s)
- Clodagh M. Carr
- School of Microbiology, University College Cork, Cork, Ireland
- SSPC-SFI Research Centre for Pharmaceuticals, University College Cork, Cork, Ireland
| | - Malene B. Keller
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | - Bijoya Paul
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | - Sune W. Schubert
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | - Kristine S. R. Clausen
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | | | - David J. Clarke
- School of Microbiology, University College Cork, Cork, Ireland
- APC Microbiome Ireland, University College Cork, Cork, Ireland
| | - Peter Westh
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | - Alan D. W. Dobson
- School of Microbiology, University College Cork, Cork, Ireland
- SSPC-SFI Research Centre for Pharmaceuticals, University College Cork, Cork, Ireland
- Environmental Research Institute, University College Cork, Cork, Ireland
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29
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Avilan L, Lichtenstein BR, König G, Zahn M, Allen MD, Oliveira L, Clark M, Bemmer V, Graham R, Austin HP, Dominick G, Johnson CW, Beckham GT, McGeehan JE, Pickford AR. Concentration-Dependent Inhibition of Mesophilic PETases on Poly(ethylene terephthalate) Can Be Eliminated by Enzyme Engineering. CHEMSUSCHEM 2023; 16:e202202277. [PMID: 36811288 DOI: 10.1002/cssc.202202277] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 02/17/2023] [Indexed: 06/18/2023]
Abstract
Enzyme-based depolymerization is a viable approach for recycling of poly(ethylene terephthalate) (PET). PETase from Ideonella sakaiensis (IsPETase) is capable of PET hydrolysis under mild conditions but suffers from concentration-dependent inhibition. In this study, this inhibition is found to be dependent on incubation time, the solution conditions, and PET surface area. Furthermore, this inhibition is evident in other mesophilic PET-degrading enzymes to varying degrees, independent of the level of PET depolymerization activity. The inhibition has no clear structural basis, but moderately thermostable IsPETase variants exhibit reduced inhibition, and the property is completely absent in the highly thermostable HotPETase, previously engineered by directed evolution, which simulations suggest results from reduced flexibility around the active site. This work highlights a limitation in applying natural mesophilic hydrolases for PET hydrolysis and reveals an unexpected positive outcome of engineering these enzymes for enhanced thermostability.
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Affiliation(s)
- Luisana Avilan
- Centre for Enzyme Innovation, School of Biological Sciences, Institute of Biological and Biomedical Sciences, University of Portsmouth, Portsmouth, PO1 2DY, United Kingdom
- BOTTLE Consortium, Golden, CO 80401, United States
| | - Bruce R Lichtenstein
- Centre for Enzyme Innovation, School of Biological Sciences, Institute of Biological and Biomedical Sciences, University of Portsmouth, Portsmouth, PO1 2DY, United Kingdom
- BOTTLE Consortium, Golden, CO 80401, United States
| | - Gerhard König
- Centre for Enzyme Innovation, School of Biological Sciences, Institute of Biological and Biomedical Sciences, University of Portsmouth, Portsmouth, PO1 2DY, United Kingdom
- BOTTLE Consortium, Golden, CO 80401, United States
| | - Michael Zahn
- Centre for Enzyme Innovation, School of Biological Sciences, Institute of Biological and Biomedical Sciences, University of Portsmouth, Portsmouth, PO1 2DY, United Kingdom
- BOTTLE Consortium, Golden, CO 80401, United States
| | - Mark D Allen
- Centre for Enzyme Innovation, School of Biological Sciences, Institute of Biological and Biomedical Sciences, University of Portsmouth, Portsmouth, PO1 2DY, United Kingdom
- BOTTLE Consortium, Golden, CO 80401, United States
| | - Liliana Oliveira
- Centre for Enzyme Innovation, School of Biological Sciences, Institute of Biological and Biomedical Sciences, University of Portsmouth, Portsmouth, PO1 2DY, United Kingdom
- BOTTLE Consortium, Golden, CO 80401, United States
| | - Matilda Clark
- Centre for Enzyme Innovation, School of Biological Sciences, Institute of Biological and Biomedical Sciences, University of Portsmouth, Portsmouth, PO1 2DY, United Kingdom
- BOTTLE Consortium, Golden, CO 80401, United States
| | - Victoria Bemmer
- Centre for Enzyme Innovation, School of Biological Sciences, Institute of Biological and Biomedical Sciences, University of Portsmouth, Portsmouth, PO1 2DY, United Kingdom
- BOTTLE Consortium, Golden, CO 80401, United States
| | - Rosie Graham
- Centre for Enzyme Innovation, School of Biological Sciences, Institute of Biological and Biomedical Sciences, University of Portsmouth, Portsmouth, PO1 2DY, United Kingdom
- BOTTLE Consortium, Golden, CO 80401, United States
| | - Harry P Austin
- Institute of Biochemistry, Department of Biotechnology & Enzyme Catalysis, University of Greifswald, D-17487, Greifswald, Germany
| | - Graham Dominick
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, United States
| | - Christopher W Johnson
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, United States
| | - Gregg T Beckham
- BOTTLE Consortium, Golden, CO 80401, United States
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, United States
| | - John E McGeehan
- Centre for Enzyme Innovation, School of Biological Sciences, Institute of Biological and Biomedical Sciences, University of Portsmouth, Portsmouth, PO1 2DY, United Kingdom
- BOTTLE Consortium, Golden, CO 80401, United States
| | - Andrew R Pickford
- Centre for Enzyme Innovation, School of Biological Sciences, Institute of Biological and Biomedical Sciences, University of Portsmouth, Portsmouth, PO1 2DY, United Kingdom
- BOTTLE Consortium, Golden, CO 80401, United States
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30
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Shi L, Liu P, Tan Z, Zhao W, Gao J, Gu Q, Ma H, Liu H, Zhu L. Complete Depolymerization of PET Wastes by an Evolved PET Hydrolase from Directed Evolution. Angew Chem Int Ed Engl 2023; 62:e202218390. [PMID: 36751696 DOI: 10.1002/anie.202218390] [Citation(s) in RCA: 24] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 02/02/2023] [Accepted: 02/07/2023] [Indexed: 02/09/2023]
Abstract
PETase displays great potential in PET depolymerization. Directed evolution has been limited to engineer PETase due to the lack of high-throughput screening assay. In this study, a novel fluorescence-based high-throughput screening assay employing a newly designed substrate, bis (2-hydroxyethyl) 2-hydroxyterephthalate (termed BHET-OH), was developed for PET hydrolases. The best variant DepoPETase produced 1407-fold more products towards amorphous PET film at 50 °C and showed a 23.3 °C higher Tm value than the PETase WT. DepoPETase enabled complete depolymerization of seven untreated PET wastes and 19.1 g PET waste (0.4 % Wenzyme /WPET ) in liter-scale reactor, suggesting that it is a potential candidate for industrial PET depolymerization processes. The molecular dynamic simulations revealed that the distal substitutions stabilized the loops around the active sites and transmitted the stabilization effect to the active sites through enhancing inter-loop interactions network.
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Affiliation(s)
- Lixia Shi
- University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing, 100049, China
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, P. R. China
- National Technology Innovation Center of Synthetic Biology, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, P. R. China
| | - Pi Liu
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, P. R. China
- National Technology Innovation Center of Synthetic Biology, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, P. R. China
| | - Zijian Tan
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, P. R. China
- Jiangsu Collaborative Innovation Centre of Chinese Medicinal Resources Industrialization, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Wei Zhao
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, P. R. China
- National Technology Innovation Center of Synthetic Biology, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, P. R. China
| | - Junfei Gao
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, P. R. China
- National Technology Innovation Center of Synthetic Biology, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, P. R. China
| | - Qun Gu
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, P. R. China
- National Technology Innovation Center of Synthetic Biology, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, P. R. China
| | - Hongwu Ma
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, P. R. China
- National Technology Innovation Center of Synthetic Biology, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, P. R. China
| | - Haifeng Liu
- Jiangsu Collaborative Innovation Centre of Chinese Medicinal Resources Industrialization, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Leilei Zhu
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, P. R. China
- National Technology Innovation Center of Synthetic Biology, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, P. R. China
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31
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Determinants for an Efficient Enzymatic Catalysis in Poly(Ethylene Terephthalate) Degradation. Catalysts 2023. [DOI: 10.3390/catal13030591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023] Open
Abstract
The enzymatic degradation of the recalcitrant poly(ethylene terephthalate) (PET) has been an important biotechnological goal. The present review focuses on the state of the art in enzymatic degradation of PET, and the challenges ahead. This review covers (i) enzymes acting on PET, (ii) protein improvements through selection or engineering, (iii) strategies to improve biocatalyst–polymer interaction and monomer yields. Finally, this review discusses critical points on PET degradation, and their related experimental aspects, that include the control of physicochemical parameters. The search for, and engineering of, PET hydrolases, have been widely studied to achieve this, and several examples are discussed here. Many enzymes, from various microbial sources, have been studied and engineered, but recently true PET hydrolases (PETases), active at moderate temperatures, were reported. For a circular economy process, terephtalic acid (TPA) production is critical. Some thermophilic cutinases and engineered PETases have been reported to release terephthalic acid in significant amounts. Some bottlenecks in enzyme performance are discussed, including enzyme activity, thermal stability, substrate accessibility, PET microstructures, high crystallinity, molecular mass, mass transfer, and efficient conversion into reusable fragments.
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32
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Tournier V, Duquesne S, Guillamot F, Cramail H, Taton D, Marty A, André I. Enzymes' Power for Plastics Degradation. Chem Rev 2023; 123:5612-5701. [PMID: 36916764 DOI: 10.1021/acs.chemrev.2c00644] [Citation(s) in RCA: 56] [Impact Index Per Article: 56.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
Plastics are everywhere in our modern way of living, and their production keeps increasing every year, causing major environmental concerns. Nowadays, the end-of-life management involves accumulation in landfills, incineration, and recycling to a lower extent. This ecological threat to the environment is inspiring alternative bio-based solutions for plastic waste treatment and recycling toward a circular economy. Over the past decade, considerable efforts have been made to degrade commodity plastics using biocatalytic approaches. Here, we provide a comprehensive review on the recent advances in enzyme-based biocatalysis and in the design of related biocatalytic processes to recycle or upcycle commodity plastics, including polyesters, polyamides, polyurethanes, and polyolefins. We also discuss scope and limitations, challenges, and opportunities of this field of research. An important message from this review is that polymer-assimilating enzymes are very likely part of the solution to reaching a circular plastic economy.
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Affiliation(s)
- Vincent Tournier
- Carbios, Parc Cataroux-Bâtiment B80, 8 rue de la Grolière, 63100 Clermont-Ferrand, France
| | - Sophie Duquesne
- Toulouse Biotechnology Institute, TBI, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France, 135, avenue de Rangueil, F-31077 Toulouse Cedex 04, France
| | - Frédérique Guillamot
- Carbios, Parc Cataroux-Bâtiment B80, 8 rue de la Grolière, 63100 Clermont-Ferrand, France
| | - Henri Cramail
- Université Bordeaux, CNRS, Bordeaux INP, LCPO, 16 Avenue Pey-Berland, 33600 Pessac, France
| | - Daniel Taton
- Université Bordeaux, CNRS, Bordeaux INP, LCPO, 16 Avenue Pey-Berland, 33600 Pessac, France
| | - Alain Marty
- Carbios, Parc Cataroux-Bâtiment B80, 8 rue de la Grolière, 63100 Clermont-Ferrand, France
| | - Isabelle André
- Toulouse Biotechnology Institute, TBI, Université de Toulouse, CNRS, INRAE, INSA, Toulouse, France, 135, avenue de Rangueil, F-31077 Toulouse Cedex 04, France
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33
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White MFM, Wallace S. A New PETase from the Human Saliva Metagenome and Its Functional Modification via Genetic Code Expansion in Bacteria. ANGEWANDTE CHEMIE (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 135:e202216963. [PMID: 38516330 PMCID: PMC10952614 DOI: 10.1002/ange.202216963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Indexed: 01/03/2023]
Abstract
The discovery and engineering of new plastic degrading enzymes is an important challenge in chemical biotechnology to enable transition to a more sustainable and circular plastics economy. This field has so far yielded a range of enzymes and microbial pathways for the recycling and valorization of plastic waste. New research from Uttamapinant et al. reports the discovery of a novel polyethylene terephthalate (PET) hydrolase from the human saliva metagenome that displays improved properties and catalytic performance over previously characterized PET hydrolases (PETases). The authors also demonstrate the site-specific incorporation of a photocaged unnatural amino acid, 2,3-diaminopropionic acid (DAP), which upon photodecaging enables covalent binding of DAP to the PET surface. Thus, this work highlights metagenomic datasets as an untapped source of new PET degrading enzymes and the chemical modification of PETases via genetic code expansion, enabling new biotechnologies for the circular plastics economy.
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Affiliation(s)
- Mirren F. M. White
- Institute of Quantitative BiologyBiochemistry and BiotechnologySchool of Biological SciencesUniversity of Edinburgh, King's BuildingsAlexander Crum Brown RoadEdinburghEH9 3FFUK
| | - Stephen Wallace
- Institute of Quantitative BiologyBiochemistry and BiotechnologySchool of Biological SciencesUniversity of Edinburgh, King's BuildingsAlexander Crum Brown RoadEdinburghEH9 3FFUK
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34
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White MFM, Wallace S. A New PETase from the Human Saliva Metagenome and Its Functional Modification via Genetic Code Expansion in Bacteria. Angew Chem Int Ed Engl 2023; 62:e202216963. [PMID: 36592375 PMCID: PMC10947391 DOI: 10.1002/anie.202216963] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 12/20/2022] [Accepted: 12/28/2022] [Indexed: 01/03/2023]
Abstract
The discovery and engineering of new plastic degrading enzymes is an important challenge in chemical biotechnology to enable transition to a more sustainable and circular plastics economy. This field has so far yielded a range of enzymes and microbial pathways for the recycling and valorization of plastic waste. New research from Uttamapinant et al. reports the discovery of a novel polyethylene terephthalate (PET) hydrolase from the human saliva metagenome that displays improved properties and catalytic performance over previously characterized PET hydrolases (PETases). The authors also demonstrate the site-specific incorporation of a photocaged unnatural amino acid, 2,3-diaminopropionic acid (DAP), which upon photodecaging enables covalent binding of DAP to the PET surface. Thus, this work highlights metagenomic datasets as an untapped source of new PET degrading enzymes and the chemical modification of PETases via genetic code expansion, enabling new biotechnologies for the circular plastics economy.
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Affiliation(s)
- Mirren F. M. White
- Institute of Quantitative BiologyBiochemistry and BiotechnologySchool of Biological SciencesUniversity of Edinburgh, King's BuildingsAlexander Crum Brown RoadEdinburghEH9 3FFUK
| | - Stephen Wallace
- Institute of Quantitative BiologyBiochemistry and BiotechnologySchool of Biological SciencesUniversity of Edinburgh, King's BuildingsAlexander Crum Brown RoadEdinburghEH9 3FFUK
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35
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Microbial Enzyme Biotechnology to Reach Plastic Waste Circularity: Current Status, Problems and Perspectives. Int J Mol Sci 2023; 24:ijms24043877. [PMID: 36835289 PMCID: PMC9967032 DOI: 10.3390/ijms24043877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2023] [Revised: 02/08/2023] [Accepted: 02/10/2023] [Indexed: 02/17/2023] Open
Abstract
The accumulation of synthetic plastic waste in the environment has become a global concern. Microbial enzymes (purified or as whole-cell biocatalysts) represent emerging biotechnological tools for waste circularity; they can depolymerize materials into reusable building blocks, but their contribution must be considered within the context of present waste management practices. This review reports on the prospective of biotechnological tools for plastic bio-recycling within the framework of plastic waste management in Europe. Available biotechnology tools can support polyethylene terephthalate (PET) recycling. However, PET represents only ≈7% of unrecycled plastic waste. Polyurethanes, the principal unrecycled waste fraction, together with other thermosets and more recalcitrant thermoplastics (e.g., polyolefins) are the next plausible target for enzyme-based depolymerization, even if this process is currently effective only on ideal polyester-based polymers. To extend the contribution of biotechnology to plastic circularity, optimization of collection and sorting systems should be considered to feed chemoenzymatic technologies for the treatment of more recalcitrant and mixed polymers. In addition, new bio-based technologies with a lower environmental impact in comparison with the present approaches should be developed to depolymerize (available or new) plastic materials, that should be designed for the required durability and for being susceptible to the action of enzymes.
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36
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Characterization of a PBAT Degradation Carboxylesterase from Thermobacillus composti KWC4. Catalysts 2023. [DOI: 10.3390/catal13020340] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The large amount of waste synthetic polyester plastics has complicated waste management and also endangering the environment due to improper littering. In this study, a novel carboxylesterase from Thermobacillus composti KWC4 (Tcca) was identified, heterologously expressed in Escherichia coli, purified and characterized with various plastic substrates. Irregular grooves were detected on polybutylene adipate terephthalate (PBAT) film by scanning electron microscopy (SEM) after Tcca treatment, and Tcca can also hydrolyze short–chain diester bis(hydroxyethyl) terephthalate (BHET). The optimal pH and temperature for Tcca were 7.0 and 40 °C, respectively. In order to explore its catalytic mechanism and improve its potential for plastic hydrolysis, we modeled the protein structure of Tcca and compared it with its homologous structures, and we identified positions that might be crucial for the binding of substrates. We generated a variety of Tcca variants by mutating these key positions; the variant F325A exhibited a more than 1.4–fold improvement in PBAT hydrolytic activity, and E80A exhibited a more than 4.1–fold increase in BHET activity when compared to the wild type. Tcca and its variants demonstrated future applicability for the recycling of bioplastic waste containing a PBAT fraction.
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37
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Schubert S, Schaller K, Bååth JA, Hunt C, Borch K, Jensen K, Brask J, Westh P. Reaction Pathways for the Enzymatic Degradation of Poly(Ethylene Terephthalate): What Characterizes an Efficient PET-Hydrolase? Chembiochem 2023; 24:e202200516. [PMID: 36399069 PMCID: PMC10108200 DOI: 10.1002/cbic.202200516] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 11/16/2022] [Accepted: 11/16/2022] [Indexed: 11/19/2022]
Abstract
Bioprocessing of polyester waste has emerged as a promising tool in the quest for a cyclic plastic economy. One key step is the enzymatic breakdown of the polymer, and this entails a complicated pathway with substrates, intermediates, and products of variable size and solubility. We have elucidated this pathway for poly(ethylene terephthalate) (PET) and four enzymes. Specifically, we combined different kinetic measurements and a novel stochastic model and found that the ability to hydrolyze internal bonds in the polymer (endo-lytic activity) was a key parameter for overall enzyme performance. Endo-lytic activity promoted the release of soluble PET fragments with two or three aromatic rings, which, in turn, were broken down with remarkable efficiency (kcat /KM values of about 105 M-1 s-1 ) in the aqueous bulk. This meant that approximatly 70 % of the final, monoaromatic products were formed via soluble di- or tri-aromatic intermediates.
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Affiliation(s)
- Sune Schubert
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, 2800 Kgs., Lyngby, Denmark
| | - Kay Schaller
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, 2800 Kgs., Lyngby, Denmark
| | | | - Cameron Hunt
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, 2800 Kgs., Lyngby, Denmark
| | - Kim Borch
- Novozymes A/S, Biologiens Vej 2, 2800 Kgs., Lyngby, Denmark
| | - Kenneth Jensen
- Novozymes A/S, Biologiens Vej 2, 2800 Kgs., Lyngby, Denmark
| | - Jesper Brask
- Novozymes A/S, Biologiens Vej 2, 2800 Kgs., Lyngby, Denmark
| | - Peter Westh
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, 2800 Kgs., Lyngby, Denmark
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38
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von Haugwitz G, Han X, Pfaff L, Li Q, Wei H, Gao J, Methling K, Ao Y, Brack Y, Mican J, Feiler CG, Weiss MS, Bednar D, Palm GJ, Lalk M, Lammers M, Damborsky J, Weber G, Liu W, Bornscheuer UT, Wei R. Structural Insights into (Tere)phthalate-Ester Hydrolysis by a Carboxylesterase and Its Role in Promoting PET Depolymerization. ACS Catal 2022; 12:15259-15270. [PMID: 36570084 PMCID: PMC9764356 DOI: 10.1021/acscatal.2c03772] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 10/09/2022] [Indexed: 12/03/2022]
Abstract
TfCa, a promiscuous carboxylesterase from Thermobifida fusca, was found to hydrolyze polyethylene terephthalate (PET) degradation intermediates such as bis(2-hydroxyethyl) terephthalate (BHET) and mono-(2-hydroxyethyl)-terephthalate (MHET). In this study, we elucidated the structures of TfCa in its apo form, as well as in complex with a PET monomer analogue and with BHET. The structure-function relationship of TfCa was investigated by comparing its hydrolytic activity on various ortho- and para-phthalate esters of different lengths. Structure-guided rational engineering of amino acid residues in the substrate-binding pocket resulted in the TfCa variant I69W/V376A (WA), which showed 2.6-fold and 3.3-fold higher hydrolytic activity on MHET and BHET, respectively, than the wild-type enzyme. TfCa or its WA variant was mixed with a mesophilic PET depolymerizing enzyme variant [Ideonella sakaiensis PETase (IsPETase) PM] to degrade PET substrates of various crystallinity. The dual enzyme system with the wild-type TfCa or its WA variant produced up to 11-fold and 14-fold more terephthalate (TPA) than the single IsPETase PM, respectively. In comparison to the recently published chimeric fusion protein of IsPETase and MHETase, our system requires 10% IsPETase and one-fourth of the reaction time to yield the same amount of TPA under similar PET degradation conditions. Our simple dual enzyme system reveals further advantages in terms of cost-effectiveness and catalytic efficiency since it does not require time-consuming and expensive cross-linking and immobilization approaches.
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Affiliation(s)
- Gerlis von Haugwitz
- Department
of Biotechnology and Enzyme Catalysis, Institute of Biochemistry, University of Greifswald, Felix-Hausdorff-Str. 4, 17487 Greifswald, Germany
| | - Xu Han
- Tianjin
Institute of Industrial Biotechnology, Chinese
Academy of Sciences, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin 300308, China,National
Technology Innovation Center of Synthetic Biology, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin 300308, China
| | - Lara Pfaff
- Department
of Biotechnology and Enzyme Catalysis, Institute of Biochemistry, University of Greifswald, Felix-Hausdorff-Str. 4, 17487 Greifswald, Germany
| | - Qian Li
- Tianjin
Institute of Industrial Biotechnology, Chinese
Academy of Sciences, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin 300308, China,National
Technology Innovation Center of Synthetic Biology, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin 300308, China
| | - Hongli Wei
- Tianjin
Institute of Industrial Biotechnology, Chinese
Academy of Sciences, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin 300308, China,National
Technology Innovation Center of Synthetic Biology, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin 300308, China
| | - Jian Gao
- Tianjin
Institute of Industrial Biotechnology, Chinese
Academy of Sciences, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin 300308, China,National
Technology Innovation Center of Synthetic Biology, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin 300308, China
| | - Karen Methling
- Department
of Cellular Biochemistry and Metabolomics, Institute of Biochemistry, University of Greifswald, Felix-Hausdorff-Str. 4, 17487 Greifswald, Germany
| | - Yufei Ao
- Department
of Biotechnology and Enzyme Catalysis, Institute of Biochemistry, University of Greifswald, Felix-Hausdorff-Str. 4, 17487 Greifswald, Germany,University
of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, China
| | - Yannik Brack
- Department
of Biotechnology and Enzyme Catalysis, Institute of Biochemistry, University of Greifswald, Felix-Hausdorff-Str. 4, 17487 Greifswald, Germany
| | - Jan Mican
- Loschmidt
Laboratories, Department of Experimental Biology and RECETOX, Faculty
of Science, Masaryk University, Kamenice 5/C13, 625 00 Brno, Czech Republic,International
Clinical Research Center, St. Anne’s
University Hospital, Pekarska 53, 656 91 Brno, Czech Republic
| | - Christian G. Feiler
- Macromolecular
Crystallography, Helmholtz-Zentrum Berlin, Alber-Einstein-Straße 15, 12489 Berlin, Germany
| | - Manfred S. Weiss
- Macromolecular
Crystallography, Helmholtz-Zentrum Berlin, Alber-Einstein-Straße 15, 12489 Berlin, Germany
| | - David Bednar
- Loschmidt
Laboratories, Department of Experimental Biology and RECETOX, Faculty
of Science, Masaryk University, Kamenice 5/C13, 625 00 Brno, Czech Republic,International
Clinical Research Center, St. Anne’s
University Hospital, Pekarska 53, 656 91 Brno, Czech Republic
| | - Gottfried J. Palm
- Department
of Synthetic and Structural Biochemistry, Institute of Biochemistry, University of Greifswald, Felix-Hausdorff-Str. 4, 17487 Greifswald, Germany
| | - Michael Lalk
- Department
of Cellular Biochemistry and Metabolomics, Institute of Biochemistry, University of Greifswald, Felix-Hausdorff-Str. 4, 17487 Greifswald, Germany
| | - Michael Lammers
- Department
of Synthetic and Structural Biochemistry, Institute of Biochemistry, University of Greifswald, Felix-Hausdorff-Str. 4, 17487 Greifswald, Germany
| | - Jiri Damborsky
- Loschmidt
Laboratories, Department of Experimental Biology and RECETOX, Faculty
of Science, Masaryk University, Kamenice 5/C13, 625 00 Brno, Czech Republic,International
Clinical Research Center, St. Anne’s
University Hospital, Pekarska 53, 656 91 Brno, Czech Republic
| | - Gert Weber
- Macromolecular
Crystallography, Helmholtz-Zentrum Berlin, Alber-Einstein-Straße 15, 12489 Berlin, Germany
| | - Weidong Liu
- Tianjin
Institute of Industrial Biotechnology, Chinese
Academy of Sciences, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin 300308, China,National
Technology Innovation Center of Synthetic Biology, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin 300308, China,University
of Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, China,
| | - Uwe T. Bornscheuer
- Department
of Biotechnology and Enzyme Catalysis, Institute of Biochemistry, University of Greifswald, Felix-Hausdorff-Str. 4, 17487 Greifswald, Germany,
| | - Ren Wei
- Department
of Biotechnology and Enzyme Catalysis, Institute of Biochemistry, University of Greifswald, Felix-Hausdorff-Str. 4, 17487 Greifswald, Germany,
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39
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Tarazona NA, Wei R, Brott S, Pfaff L, Bornscheuer UT, Lendlein A, Machatschek R. Rapid depolymerization of poly(ethylene terephthalate) thin films by a dual-enzyme system and its impact on material properties. CHEM CATALYSIS 2022; 2:3573-3589. [PMID: 37350932 PMCID: PMC10284027 DOI: 10.1016/j.checat.2022.11.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 10/17/2022] [Accepted: 11/04/2022] [Indexed: 06/24/2023]
Abstract
Enzymatic hydrolysis holds great promise for plastic waste recycling and upcycling. The interfacial catalysis mode, and the variability of polymer specimen properties under different degradation conditions, add to the complexity and difficulty of understanding polymer cleavage and engineering better biocatalysts. We present a systemic approach to studying the enzyme-catalyzed surface erosion of poly(ethylene terephthalate) (PET) while monitoring/controlling operating conditions in real time with simultaneous detection of mass loss and changes in viscoelastic behavior. PET nanofilms placed on water showed a porous morphology and a thickness-dependent glass transition temperature (Tg) between 40°C and 44°C, which is >20°C lower than the Tg of bulk amorphous PET. Hydrolysis by a dual-enzyme system containing thermostabilized variants of Ideonella sakaiensis PETase and MHETase resulted in a maximum depolymerization of 70% in 1 h at 50°C. We demonstrate that increased accessible surface area, amorphization, and Tg reduction speed up PET degradation while simultaneously lowering the threshold for degradation-induced crystallization.
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Affiliation(s)
- Natalia A. Tarazona
- Institute of Active Polymers, Helmholtz-Zentrum Hereon, Kantstraße 55, 14513 Teltow, Germany
| | - Ren Wei
- Institute of Biochemistry, University of Greifswald, Felix-Hausdorff-Straße 8, 17489 Greifswald, Germany
| | - Stefan Brott
- Institute of Biochemistry, University of Greifswald, Felix-Hausdorff-Straße 8, 17489 Greifswald, Germany
| | - Lara Pfaff
- Institute of Biochemistry, University of Greifswald, Felix-Hausdorff-Straße 8, 17489 Greifswald, Germany
| | - Uwe T. Bornscheuer
- Institute of Biochemistry, University of Greifswald, Felix-Hausdorff-Straße 8, 17489 Greifswald, Germany
| | - Andreas Lendlein
- Institute of Active Polymers, Helmholtz-Zentrum Hereon, Kantstraße 55, 14513 Teltow, Germany
- Institute of Chemistry, University of Potsdam, Karl-Liebknecht-Straße 24-25, 14469 Potsdam, Germany
| | - Rainhard Machatschek
- Institute of Active Polymers, Helmholtz-Zentrum Hereon, Kantstraße 55, 14513 Teltow, Germany
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40
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Weigert S, Perez‐Garcia P, Gisdon FJ, Gagsteiger A, Schweinshaut K, Ullmann GM, Chow J, Streit WR, Höcker B. Investigation of the halophilic PET hydrolase PET6 from Vibrio gazogenes. Protein Sci 2022; 31:e4500. [PMID: 36336469 PMCID: PMC9679969 DOI: 10.1002/pro.4500] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 10/21/2022] [Accepted: 11/03/2022] [Indexed: 11/09/2022]
Abstract
The handling of plastic waste and the associated ubiquitous occurrence of microplastic poses one of the biggest challenges of our time. Recent investigations of plastic degrading enzymes have opened new prospects for biological microplastic decomposition as well as recycling applications. For polyethylene terephthalate, in particular, several natural and engineered enzymes are known to have such promising properties. From a previous study that identified new PETase candidates by homology search, we chose the candidate PET6 from the globally distributed, halophilic organism Vibrio gazogenes for further investigation. By mapping the occurrence of Vibrios containing PET6 homologs we demonstrated their ubiquitous prevalence in the pangenome of several Vibrio strains. The biochemical characterization of PET6 showed that PET6 has a comparatively lower activity than other enzymes but also revealed a superior turnover at very high salt concentrations. The crystal structure of PET6 provides structural insights into this adaptation to saline environments. By grafting only a few beneficial mutations from other PET degrading enzymes onto PET6, we increased the activity up to three-fold, demonstrating the evolutionary potential of the enzyme. MD simulations of the variant helped rationalize the mutational effects of those mutants and elucidate the interaction of the enzyme with a PET substrate. With tremendous amounts of plastic waste in the Ocean and the prevalence of Vibrio gazogenes in marine biofilms and estuarine marshes, our findings suggest that Vibrio and the PET6 enzyme are worthy subjects to study the PET degradation in marine environments.
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Affiliation(s)
| | - Pablo Perez‐Garcia
- Department of Microbiology and BiotechnologyUniversity of HamburgHamburgGermany
| | | | | | | | | | - Jennifer Chow
- Department of Microbiology and BiotechnologyUniversity of HamburgHamburgGermany
| | - Wolfgang R. Streit
- Department of Microbiology and BiotechnologyUniversity of HamburgHamburgGermany
| | - Birte Höcker
- Department of BiochemistryUniversity of BayreuthBayreuthGermany
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Kawai F, Furushima Y, Mochizuki N, Muraki N, Yamashita M, Iida A, Mamoto R, Tosha T, Iizuka R, Kitajima S. Efficient depolymerization of polyethylene terephthalate (PET) and polyethylene furanoate by engineered PET hydrolase Cut190. AMB Express 2022; 12:134. [DOI: 10.1186/s13568-022-01474-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 10/05/2022] [Indexed: 11/10/2022] Open
Abstract
AbstractThe enzymatic recycling of polyethylene terephthalate (PET) can be a promising approach to tackle the problem of plastic waste. The thermostability and activity of PET-hydrolyzing enzymes are still insufficient for practical application. Pretreatment of PET waste is needed for bio-recycling. Here, we analyzed the degradation of PET films, packages, and bottles using the newly engineered cutinase Cut190. Using gel permeation chromatography and high-performance liquid chromatography, the degradation of PET films by the Cut190 variant was shown to proceed via a repeating two-step hydrolysis process; initial endo-type scission of a surface polymer chain, followed by exo-type hydrolysis to produce mono/bis(2-hydroxyethyl) terephthalate and terephthalate from the ends of fragmented polymer molecules. Amorphous PET powders were degraded more than twofold higher than amorphous PET film with the same weight. Moreover, homogenization of post-consumer PET products, such as packages and bottles, increased their degradability, indicating the importance of surface area for the enzymatic hydrolysis of PET. In addition, it was required to maintain an alkaline pH to enable continuous enzymatic hydrolysis, by increasing the buffer concentration (HEPES, pH 9.0) depending on the level of the acidic products formed. The cationic surfactant dodecyltrimethylammonium chloride promoted PET degradation via adsorption on the PET surface and binding to the anionic surface of the Cut190 variant. The Cut190 variant also hydrolyzed polyethylene furanoate. Using the best performing Cut190 variant (L136F/Q138A/S226P/R228S/D250C-E296C/Q123H/N202H/K305del/L306del/N307del) and amorphous PET powders, more than 90 mM degradation products were obtained in 3 days and approximately 80 mM in 1 day.
Graphical Abstract
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Li Z, Zhao Y, Wu P, Wang H, Li Q, Gao J, Qin HM, Wei H, Bornscheuer UT, Han X, Wei R, Liu W. Structural insight and engineering of a plastic degrading hydrolase Ple629. Biochem Biophys Res Commun 2022; 626:100-106. [DOI: 10.1016/j.bbrc.2022.07.103] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Accepted: 07/26/2022] [Indexed: 11/30/2022]
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