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Polo G, Lionetto F, Giordano ME, Lionetto MG. Interaction of Micro- and Nanoplastics with Enzymes: The Case of Carbonic Anhydrase. Int J Mol Sci 2024; 25:9716. [PMID: 39273668 PMCID: PMC11396312 DOI: 10.3390/ijms25179716] [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: 08/03/2024] [Revised: 08/30/2024] [Accepted: 09/05/2024] [Indexed: 09/15/2024] Open
Abstract
Microplastics (MPs) and nanoplastics (NPs) have emerged as significant environmental pollutants with potential detrimental effects on ecosystems and human health. Several studies indicate their interaction with enzymes; this topic represents a multifaceted research field encompassing several areas of interest from the toxicological and ecotoxicological impact of MPs and NPs on humans and wildlife to the biodegradation of plastics by microbial enzymes. This review aims to provide a critical analysis of the state-of-the-art knowledge of the interaction of MPs and NPs on the enzyme carbonic anhydrase (CA), providing recent insights, analyzing the knowledge gaps in the field, and drawing future perspectives of the research and its application. CA is a widespread and crucial enzyme in various organisms; it is critical for various physiological processes in animals, plants, and bacteria. It catalyzes the reversible hydration of CO2, which is essential for respiration, acid-base balance, pH homeostasis, ion transport, calcification, and photosynthesis. Studies demonstrate that MPs and NPs can inhibit CA activity with mechanisms including adsorption to the enzyme surface and subsequent conformational changes. In vitro and in silico studies highlight the role of electrostatic and hydrophobic interactions in these processes. In vivo studies present mixed results, which are influenced by factors like particle type, size, concentration, and organism type. Moreover, the potentiality of the esterase activity of CA for plastic degradation is discussed. The complexity of the interaction between CA and MPs/NPs underscores the need for further research to fully understand the ecological and health impacts of MPs and NPs on CA activity and expression and glimpses of the potentiality and perspectives in this field.
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Affiliation(s)
- Gregorio Polo
- Department of Mathematics and Physics, University of Salento, Via per Arnesano, 73100 Lecce, Italy
| | - Francesca Lionetto
- Department of Engineering for Innovation, University of Salento, Via per Monteroni, 73100 Lecce, Italy
| | - Maria Elena Giordano
- Department of Environmental and Biological Sciences and Technologies (DiSTeBA), University of Salento, Via per Monteroni, 73100 Lecce, Italy
| | - Maria Giulia Lionetto
- Department of Environmental and Biological Sciences and Technologies (DiSTeBA), University of Salento, Via per Monteroni, 73100 Lecce, Italy
- National Biodiversity Future Center (NBFC), 90133 Palermo, Italy
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2
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Guo X, Jiang Y, Xie D, Zhou Y. Computational investigation on the binding modes of PET polymer to PETase. J Biomol Struct Dyn 2024; 42:6842-6849. [PMID: 37505088 DOI: 10.1080/07391102.2023.2240893] [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: 04/10/2023] [Accepted: 07/08/2023] [Indexed: 07/29/2023]
Abstract
Poly(ethylene terephthalate) (PET) has been widely utilized in daily life, but its non-degradability has induced severe environmental and health problems. Recently, PETase, which has been isolated from bacterium Ideonella sakaiensisis, was reported to have the highest PET degradation activity and specificity under room temperature, but no crystal structure for PET in complex with PETase has been reported. To provide deep insight into the binding mode of PET polymer on PETase and the binding interactions, we employed molecular docking and molecular dynamics simulations to study the substrate binding at the atomic level. Different PET oligomers have been studied with chain lengths varying from 2 to 8. In addition, the binding energies and hot-spot residues were analyzed to gain better insights into the binding mechanism by MM/GBSA approach. The PET oligomers adopt stable and reactive conformations in a shallow cleft on a flat surface of PETase. The binding cleft can only accommodate four moieties, and others beyond the region will be stabilized by the π-stacking interactions with Trp156 at the terephthalic acid terminal. Our studies provide a clear picture of how the binding mode of PET polymer and its interactions with PETase change with the chain length. Those studies would provide useful information for the rational design of catalytically more efficient PETase variants toward plastic degradation.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Xuehui Guo
- Institute of Theoretical and Computational Chemistry, Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
| | - Yiming Jiang
- Institute of Theoretical and Computational Chemistry, Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
| | - Daiqian Xie
- Institute of Theoretical and Computational Chemistry, Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
| | - Yanzi Zhou
- Institute of Theoretical and Computational Chemistry, Key Laboratory of Mesoscopic Chemistry, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing, China
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3
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Zhang Y, Hancock WO. Measuring PETase enzyme kinetics by single-molecule microscopy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.24.590935. [PMID: 38712273 PMCID: PMC11071475 DOI: 10.1101/2024.04.24.590935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
Polyethylene terephthalate (PET) is one of the most widely produced man-made polymers and is a significant contributor to microplastics pollution. The environmental and human health impacts of microplastics pollution have motivated a concerted effort to develop microbe- and enzyme-based strategies to degrade PET and similar plastics. A PETase derived from the bacteria Ideonella sakaiensis was previously shown to enzymatically degrade PET, triggering multidisciplinary efforts to improve the robustness and activity of this and other PETases. However, because these enzymes only erode the surface of the insoluble PET substrate, it is difficult to measure standard kinetic parameters, such as kon, koff and kcat, complicating interpretation of the activity of mutants using traditional enzyme kinetics frameworks. To address this challenge, we developed a single-molecule microscopy assay that quantifies the landing rate and binding duration of quantum dot-labeled PETase enzymes interacting with a surface-immobilized PET film. Wild-type PETase binding durations were well fit by a biexponential with a fast population having a 2.7 s time constant, interpreted as active binding events, and a slow population interpreted as non-specific binding interactions that last tens of seconds. A previously described hyperactive mutant, S238F/W159H had both a faster on-rate and a slower off-rate than wild-type PETase, potentially explaining its enhanced activity. Because this single-molecule approach provides a more detailed mechanistic picture of PETase enzymatic activity than standard bulk assays, it should aid future efforts to engineer more robust and active PETases to combat global microplastics pollution.
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Affiliation(s)
- Yuwei Zhang
- Department of Biomedical Engineering, Pennsylvania State University, University Park, Pennsylvania, USA
| | - William O. Hancock
- Department of Biomedical Engineering, Pennsylvania State University, University Park, Pennsylvania, USA
- Department of Chemistry, Pennsylvania State University, University Park, Pennsylvania, USA
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4
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Oda K, Wlodawer A. Development of Enzyme-Based Approaches for Recycling PET on an Industrial Scale. Biochemistry 2024. [PMID: 38285602 DOI: 10.1021/acs.biochem.3c00554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2024]
Abstract
Pollution by plastics such as polyethylene (PE), polypropylene (PP), polyvinyl chloride (PVC), polyurethane (PUR), polyamide (PA), polystyrene (PS), and poly(ethylene terephthalate) (PET) is now gaining worldwide attention as a critical environmental issue, closely linked to climate change. Among them, PET is particularly prone to hydrolysis, breaking down into its constituents, ethylene glycol (EG) and terephthalate (TPA). Biorecycling or bioupcycling stands out as one of the most promising methods for addressing PET pollution. For dealing with pollution by the macrosize PET, a French company Carbios has developed a pilot-scale plant for biorecycling waste PET beverage bottles into new bottles using derivatives of thermophilic leaf compost cutinase (LCC). However, this system still provides significant challenges in its practical implementation. For the micro- or nanosize PET pollution that poses significant human health risks, including cancer, no industrial-scale approach has been established so far, despite the need to develop such technologies. In this Perspective, we explore the enhancement of the low activity and thermostability of the enzyme PETase to match that of LCC, along with the potential application of microbes and enzymes for the treatment of waste PET as microplastics. Additionally, we discuss the shortcomings of the current biorecycling protocols from a life cycle assessment perspective, covering aspects such as the diversity of PET-hydrolyzing enzymes in nature, the catalytic mechanism for crystallized PET, and more. We also provide an overview of the Ideonella sakaiensis system, highlighting its ability to operate and grow at moderate temperatures, in contrast to high-temperature processes.
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Affiliation(s)
- Kohei Oda
- Department of Applied Biology, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Alexander Wlodawer
- Center for Structural Biology, National Cancer Institute, Frederick, Maryland 21702, United States
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5
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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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6
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Aristizábal-Lanza L, Mankar SV, Tullberg C, Zhang B, Linares-Pastén JA. Comparison of the enzymatic depolymerization of polyethylene terephthalate and AkestraTM using Humicola insolens cutinase. FRONTIERS IN CHEMICAL ENGINEERING 2022. [DOI: 10.3389/fceng.2022.1048744] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The enzymatic depolymerization of synthetic polyesters has become of great interest in recycling plastics. Most of the research in this area focuses on the depolymerization of polyethylene terephthalate (PET) due to its widespread use in various applications. However, the enzymatic activity on other commercial polyesters is less frequently investigated. Therefore, AkestraTM attracted our attention, which is a copolymer derived from PET with a partially biobased spirocyclic acetal structure. In this study, the activity of Humicola insolens cutinase (HiCut) on PET and AkestraTM films and powder was investigated. HiCut showed higher depolymerization activity on amorphous PET films than on Akestra™ films. However, an outstanding performance was achieved on AkestraTM powder, reaching 38% depolymerization in 235h, while only 12% for PET powder. These results are consistent with the dependence of the enzymes on the crystallinity of the polymer since Akestra™ is amorphous while the PET powder has 14% crystallinity. On the other hand, HiCut docking studies and molecular dynamic simulations (MD) suggested that the PET-derived mono (hydroxyethyl)terephthalate dimer (MHET)2 is a hydrolyzable ligand, producing terephthalic acid (TPA), while the Akestra™-derived TPA-spiroglycol ester is not, which is consistent with the depolymerization products determined experimentally. MD studies also suggest ligand-induced local conformational changes in the active site.
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7
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Khairul Anuar NFS, Huyop F, Ur-Rehman G, Abdullah F, Normi YM, Sabullah MK, Abdul Wahab R. An Overview into Polyethylene Terephthalate (PET) Hydrolases and Efforts in Tailoring Enzymes for Improved Plastic Degradation. Int J Mol Sci 2022; 23:12644. [PMID: 36293501 PMCID: PMC9603852 DOI: 10.3390/ijms232012644] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Revised: 10/12/2022] [Accepted: 10/18/2022] [Indexed: 11/18/2022] Open
Abstract
Plastic or microplastic pollution is a global threat affecting ecosystems, with the current generation reaching as much as 400 metric tons per/year. Soil ecosystems comprising agricultural lands act as microplastics sinks, though the impact could be unexpectedly more far-reaching. This is troubling as most plastic forms, such as polyethylene terephthalate (PET), formed from polymerized terephthalic acid (TPA) and ethylene glycol (EG) monomers, are non-biodegradable environmental pollutants. The current approach to use mechanical, thermal, and chemical-based treatments to reduce PET waste remains cost-prohibitive and could potentially produce toxic secondary pollutants. Thus, better remediation methods must be developed to deal with plastic pollutants in marine and terrestrial environments. Enzymatic treatments could be a plausible avenue to overcome plastic pollutants, given the near-ambient conditions under which enzymes function without the need for chemicals. The discovery of several PET hydrolases, along with further modification of the enzymes, has considerably aided efforts to improve their ability to degrade the ester bond of PET. Hence, this review emphasizes PET-degrading microbial hydrolases and their contribution to alleviating environmental microplastics. Information on the molecular and degradation mechanisms of PET is also highlighted in this review, which might be useful in the future rational engineering of PET-hydrolyzing enzymes.
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Affiliation(s)
- Nurul Fatin Syamimi Khairul Anuar
- Department of Biosciences, Faculty of Science, Universiti Teknologi Malaysia, Johor Bahru 81310, Malaysia
- Enzyme Technology and Green Synthesis Research Group, Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, Johor Bahru 81310, Malaysia
| | - Fahrul Huyop
- Department of Biosciences, Faculty of Science, Universiti Teknologi Malaysia, Johor Bahru 81310, Malaysia
| | - Ghani Ur-Rehman
- Enzyme Technology and Green Synthesis Research Group, Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, Johor Bahru 81310, Malaysia
- Advanced Membrane Technology Research Centre (AMTEC), Universiti Teknologi Malaysia, Johor Bahru 81310, Malaysia
| | - Faizuan Abdullah
- Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, Johor Bahru 81310, Malaysia
| | - Yahaya M. Normi
- Enzyme and Microbial Technology Research Center, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang 43400, Malaysia
- Department of Cell and Molecular Biology, Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, Serdang 43400, Malaysia
| | - Mohd Khalizan Sabullah
- Faculty of Science and Natural Resources, Universiti Malaysia Sabah, Kota Kinabalu 88400, Malaysia
| | - Roswanira Abdul Wahab
- Enzyme Technology and Green Synthesis Research Group, Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, Johor Bahru 81310, Malaysia
- Advanced Membrane Technology Research Centre (AMTEC), Universiti Teknologi Malaysia, Johor Bahru 81310, Malaysia
- Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, Johor Bahru 81310, Malaysia
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8
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Sonnendecker C, Oeser J, Richter PK, Hille P, Zhao Z, Fischer C, Lippold H, Blázquez‐Sánchez P, Engelberger F, Ramírez‐Sarmiento CA, Oeser T, Lihanova Y, Frank R, Jahnke H, Billig S, Abel B, Sträter N, Matysik J, Zimmermann W. Low Carbon Footprint Recycling of Post-Consumer PET Plastic with a Metagenomic Polyester Hydrolase. CHEMSUSCHEM 2022; 15:e202101062. [PMID: 34129279 PMCID: PMC9303343 DOI: 10.1002/cssc.202101062] [Citation(s) in RCA: 42] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/14/2021] [Indexed: 06/01/2023]
Abstract
Earth is flooded with plastics and the need for sustainable recycling strategies for polymers has become increasingly urgent. Enzyme-based hydrolysis of post-consumer plastic is an emerging strategy for closed-loop recycling of polyethylene terephthalate (PET). The polyester hydrolase PHL7, isolated from a compost metagenome, completely hydrolyzes amorphous PET films, releasing 91 mg of terephthalic acid per hour and mg of enzyme. Vertical scanning interferometry shows degradation rates of the PET film of 6.8 μm h-1 . Structural analysis indicates the importance of leucine at position 210 for the extraordinarily high PET-hydrolyzing activity of PHL7. Within 24 h, 0.6 mgenzyme gPET -1 completely degrades post-consumer thermoform PET packaging in an aqueous buffer at 70 °C without any energy-intensive pretreatments. Terephthalic acid recovered from the enzymatic hydrolysate is then used to synthesize virgin PET, demonstrating the potential of polyester hydrolases as catalysts in sustainable PET recycling processes with a low carbon footprint.
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Affiliation(s)
| | - Juliane Oeser
- Department of Microbiology and Bioprocess Technology Institute of BiochemistryLeipzig University04103LeipzigGermany
| | - P. Konstantin Richter
- Institute of Bioanalytical Chemistry, Centre for Biotechnology and BiomedicineLeipzig University04103LeipzigGermany
| | - Patrick Hille
- Department of Microbiology and Bioprocess Technology Institute of BiochemistryLeipzig University04103LeipzigGermany
| | - Ziyue Zhao
- Institute of Analytical ChemistryLeipzig University04103LeipzigGermany
| | - Cornelius Fischer
- Helmholtz-Zentrum Dresden-Rossendorf (HZDR)Institut für Ressourcenökologie Abteilung Reaktiver TransportD-04318LeipzigGermany
| | - Holger Lippold
- Helmholtz-Zentrum Dresden-Rossendorf (HZDR)Institut für Ressourcenökologie Abteilung Reaktiver TransportD-04318LeipzigGermany
| | - Paula Blázquez‐Sánchez
- Institute for Biological and Medical Engineering Schools of Engineering, Medicine and Biological SciencesPontificia Universidad Católica de ChileSantiago7820436Chile
- ANID—Millennium Science Initiative ProgramMillennium Institute for Integrative Biology (iBio)Santiago8331150Chile
| | - Felipe Engelberger
- Institute for Biological and Medical Engineering Schools of Engineering, Medicine and Biological SciencesPontificia Universidad Católica de ChileSantiago7820436Chile
- ANID—Millennium Science Initiative ProgramMillennium Institute for Integrative Biology (iBio)Santiago8331150Chile
| | - César A. Ramírez‐Sarmiento
- Institute for Biological and Medical Engineering Schools of Engineering, Medicine and Biological SciencesPontificia Universidad Católica de ChileSantiago7820436Chile
- ANID—Millennium Science Initiative ProgramMillennium Institute for Integrative Biology (iBio)Santiago8331150Chile
| | - Thorsten Oeser
- Department of Microbiology and Bioprocess Technology Institute of BiochemistryLeipzig University04103LeipzigGermany
| | - Yuliia Lihanova
- Institute of Analytical ChemistryLeipzig University04103LeipzigGermany
| | - Ronny Frank
- Centre for Biotechnology and Biomedicine Molecular Biological-Biochemical Processing TechnologyLeipzig University04103LeipzigGermany
| | - Heinz‐Georg Jahnke
- Centre for Biotechnology and Biomedicine Molecular Biological-Biochemical Processing TechnologyLeipzig University04103LeipzigGermany
| | - Susan Billig
- Institute of Analytical ChemistryLeipzig University04103LeipzigGermany
| | - Bernd Abel
- Leibniz Institute of Surface Engineering (IOM)Wilhelm-Ostwald-Institute of Physical and Theoretical Chemistry04103LeipzigGermany
| | - Norbert Sträter
- Institute of Bioanalytical Chemistry, Centre for Biotechnology and BiomedicineLeipzig University04103LeipzigGermany
| | - Jörg Matysik
- Institute of Analytical ChemistryLeipzig University04103LeipzigGermany
| | - Wolfgang Zimmermann
- Institute of Analytical ChemistryLeipzig University04103LeipzigGermany
- Department of Microbiology and Bioprocess Technology Institute of BiochemistryLeipzig University04103LeipzigGermany
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9
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Srikanth M, Sandeep TSRS, Sucharitha K, Godi S. Biodegradation of plastic polymers by fungi: a brief review. BIORESOUR BIOPROCESS 2022; 9:42. [PMID: 38647755 PMCID: PMC10991219 DOI: 10.1186/s40643-022-00532-4] [Citation(s) in RCA: 53] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 03/27/2022] [Indexed: 11/10/2022] Open
Abstract
Plastic polymers are non-degradable solid wastes that have become a great threat to the whole world and degradation of these plastics would take a few decades. Compared with other degradation processes, the biodegradation process is the most effective and best way for plastic degradation due to its non-polluting mechanism, eco-friendly nature, and cost-effectiveness. Biodegradation of synthetic plastics is a very slow process that also involves environmental factors and the action of wild microbial species. In this plastic biodegradation, fungi play a pivotal role, it acts on plastics by secreting some degrading enzymes, i.e., cutinase`, lipase, and proteases, lignocellulolytic enzymes, and also the presence of some pro-oxidant ions can cause effective degradation. The oxidation or hydrolysis by the enzyme creates functional groups that improve the hydrophilicity of polymers, and consequently degrade the high molecular weight polymer into low molecular weight. This leads to the degradation of plastics within a few days. Some well-known species which show effective degradation on plastics are Aspergillus nidulans, Aspergillus flavus, Aspergillus glaucus, Aspergillus oryzae, Aspergillus nomius, Penicillium griseofulvum, Bjerkandera adusta, Phanerochaete chrysosporium, Cladosporium cladosporioides, etc., and some other saprotrophic fungi, such as Pleurotus abalones, Pleurotus ostreatus, Agaricus bisporus and Pleurotus eryngii which also helps in degradation of plastics by growing on them. Some studies say that the degradation of plastics was more effective when photodegradation and thermo-oxidative mechanisms involved with the biodegradation simultaneously can make the degradation faster and easier. This present review gives current knowledge regarding different species of fungi that are involved in the degradation of plastics by their different enzymatic mechanisms to degrade different forms of plastic polymers.
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Affiliation(s)
- Munuru Srikanth
- Department of Biotechnology, College of Science and Technology, Andhra University, Visakhapatnam, 530003, India
| | - T S R S Sandeep
- Department of Biotechnology, College of Science and Technology, Andhra University, Visakhapatnam, 530003, India.
| | - Kuvala Sucharitha
- Department of Biotechnology, Pydah Degree College, Affiliated to Andhra University, Visakhapatnam, India
| | - Sudhakar Godi
- Department of Human Genetics, College of Science and Technology, Andhra University, Visakhapatnam, 530003, India
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Affiliation(s)
- Dhananjay Dileep
- Chemical and Biological Engineering, Sweeney Hall, Iowa State University 618 Bissell Road Ames 50011 Iowa USA
| | - Michael Forrester
- Chemical and Biological Engineering, Sweeney Hall, Iowa State University 618 Bissell Road Ames 50011 Iowa USA
| | - Eric Cochran
- Chemical and Biological Engineering, Sweeney Hall, Iowa State University 618 Bissell Road Ames 50011 Iowa USA
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11
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Kawai F. Emerging Strategies in Polyethylene Terephthalate Hydrolase Research for Biorecycling. CHEMSUSCHEM 2021; 14:4115-4122. [PMID: 33949146 DOI: 10.1002/cssc.202100740] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 05/02/2021] [Indexed: 06/12/2023]
Abstract
The research on polyethylene terephthalate (PET) hydrolyzing enzymes started in 2005; several studies are now nearing the objective of their application in biorecycling of PET, which is an urgent environmental issue. The thermostability of PET hydrolases must be higher than 70 °C, which has already been established by several thermophilic cutinases, as higher thermostability results in higher activity. Additionally, pretreatment of waste PET to more enzyme-attackable forms is necessary for PET biorecycling. This Minireview summarizes research on enzymatic PET hydrolysis from two viewpoints: 1) improvement of PET hydrolases by focusing on their thermostabilities by mutation of enzyme genes, their expression in several hosts, and their modifications; and 2) processing of waste PET to readily biodegradable forms. Finally, the outlook of PET biorecycling is described.
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Affiliation(s)
- Fusako Kawai
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto, Japan
- Graduate School of Environmental and Life Science, Okayama University, Okayama, Japan
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12
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Moyses DN, Teixeira DA, Waldow VA, Freire DMG, Castro AM. Fungal and enzymatic bio-depolymerization of waste post-consumer poly(ethylene terephthalate) (PET) bottles using Penicillium species. 3 Biotech 2021; 11:435. [PMID: 34603913 DOI: 10.1007/s13205-021-02988-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Accepted: 09/07/2021] [Indexed: 10/20/2022] Open
Abstract
Poly(ethylene terephthalate) (PET) is a petroleum-based plastic that is massively produced and used worldwide. A promising PET recycling process to circumvent petroleum feedstock consumption and help to reduce environmental pollution is microbial or enzymatic biodegradation of post-consumer (PC) PET packages to its monomers-terephthalic acid (TPA) and ethylene glycol (EG)-or to key intermediates in PET synthesis-such as mono- and bis-(2-hydroxyethyl) terephthalate (MHET and BHET). Two species of filamentous fungi previously characterized as lipase producers (Penicillium restrictum and P. simplicissimum) were evaluated in submerged fermentation for induction of lipase production by two inducers (BHET and amorphous PET), and for biodegradation of two substrates (BHET and PC-PET). BHET induced lipase production in P. simplicissimum, achieving a peak of 606.4 U/L at 49 h (12.38 U/L.h), representing an almost twofold increase in comparison to the highest peak in the control (without inducers). Microbial biodegradation by P. simplicissimum after 28 days led to a 3.09% mass loss on PC-PET fragments. In contrast, enzymatic PC-PET depolymerization by cell-free filtrates from a P. simplicissimum culture resulted in low concentrations of BHET, MHET and TPA (up to 9.51 µmol/L), suggesting that there are mechanisms at the organism level that enhance biodegradation. Enzymatic BHET hydrolysis revealed that P. simplicissimum extracellular enzymes catalyze the release of MHET as the predominant product. Our results show that P. simplicissimum is a promising biodegrader of PC-PET that can be further explored for monomer recovery in the context of feedstock recycling processes.
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Pirillo V, Pollegioni L, Molla G. Analytical methods for the investigation of enzyme-catalyzed degradation of polyethylene terephthalate. FEBS J 2021; 288:4730-4745. [PMID: 33792200 PMCID: PMC8453989 DOI: 10.1111/febs.15850] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 03/03/2021] [Accepted: 03/29/2021] [Indexed: 01/11/2023]
Abstract
The polyester PET (poly(ethylene terephthalate)) plastic is chemically inert and remarkably persistent, posing relevant and global pollution concerns due to its accumulation in ecosystems across the globe. In past years, research focused on identifying bacteria active on PET and on the specific enzymes responsible for its degradation. Here, the enzymatic degradation of PET can be considered as an 'erosion process' that takes place on the surface of an insoluble material and results in an unusual, substrate-limited kinetic condition. In this review, we report on the most suitable models to evaluate the kinetics of PET-hydrolyzing enzymes, which takes into consideration the amount of enzyme adsorbed on the substrate, the enzyme-accessible ester bonds, and the product inhibition effects. Careful kinetic analysis is especially relevant to compare enzymes from different sources and evolved variants generated by protein engineering studies as well. Furthermore, the analytical methods most suitable to screen natural bacteria and recombinant variant libraries generated by protein engineering have been also reported. These methods rely on different detection systems and are performed both on model compounds and on different PET samples (e.g., nanoparticles, microparticles, and waste products). All this meaningful information represents an optimal starting point and boosts the process of identifying systems able to biologically recycle PET waste products.
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Affiliation(s)
- Valentina Pirillo
- The Protein Factory 2.0’Dipartimento di Biotecnologie e Scienze della VitaUniversità degli Studi dell'InsubriaVareseItaly
| | - Loredano Pollegioni
- The Protein Factory 2.0’Dipartimento di Biotecnologie e Scienze della VitaUniversità degli Studi dell'InsubriaVareseItaly
| | - Gianluca Molla
- The Protein Factory 2.0’Dipartimento di Biotecnologie e Scienze della VitaUniversità degli Studi dell'InsubriaVareseItaly
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14
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Carniel A, Waldow VDA, Castro AMD. A comprehensive and critical review on key elements to implement enzymatic PET depolymerization for recycling purposes. Biotechnol Adv 2021; 52:107811. [PMID: 34333090 DOI: 10.1016/j.biotechadv.2021.107811] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Revised: 07/15/2021] [Accepted: 07/26/2021] [Indexed: 11/25/2022]
Abstract
Plastics production and recycling chains must be refitted to a circular economy. Poly(ethylene terephthalate) (PET) is especially suitable for recycling because of its hydrolysable ester bonds and high environmental impact due to employment in single-use packaging, so that recycling processes utilizing enzymes are a promising biotechnological route to monomer recovery. However, enzymatic PET depolymerization still faces challenges to become a competitive route at an industrial level. In this review, PET characteristics as a substrate for enzymes are discussed, as well as the analytical methods used to evaluate the reaction progress. A comprehensive view on the biocatalysts used is discussed. Subsequently, different strategies pursued to improve enzymatic PET depolymerization are presented, including enzyme modification through mutagenesis, utilization of multiple enzymes, improvement of the interaction between enzymes and the hydrophobic surface of PET, and various reaction conditions (e.g., particle size, reaction medium, agitation, and additives). All scientific developments regarding these different aspects of PET depolymerization are crucial to offer a scalable and competitive technology. However, they must be integrated into global processes from upstream to downstream, discussed here at the final sections, which must be evaluated for their economic feasibility and life cycle assessment to check if PET recycling chains can be broadly incorporated into the future circular economy.
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Affiliation(s)
- Adriano Carniel
- School of Chemistry, Federal University of Rio de Janeiro (UFRJ) - Cidade Universitária, Rio de Janeiro, RJ CEP 21949-900, Brazil
| | - Vinicius de Abreu Waldow
- Petrobras Research, Development and Innovation Center (Cenpes), Av. Horácio Macedo, n° 950 - Cidade Universitária, Rio de Janeiro, RJ CEP 21941-915, Brazil
| | - Aline Machado de Castro
- Petrobras Research, Development and Innovation Center (Cenpes), Av. Horácio Macedo, n° 950 - Cidade Universitária, Rio de Janeiro, RJ CEP 21941-915, Brazil.
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15
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Oda M. Structural basis for Ca 2+-dependent catalysis of a cutinase-like enzyme and its engineering: application to enzymatic PET depolymerization. Biophys Physicobiol 2021; 18:168-176. [PMID: 34386313 PMCID: PMC8326265 DOI: 10.2142/biophysico.bppb-v18.018] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 06/28/2021] [Indexed: 12/17/2022] Open
Abstract
A cutinase-like enzyme from Saccharomonospora viridis AHK190, Cut190, can depolymerize polyethylene terephthalate (PET). As high activity at approximately 70°C is required for PET depolymerization, structure-based protein engineering of Cut190 was carried out. Crystal structure information of the Cut190 mutants was used for protein engineering and for evaluating the molecular basis of activity and thermal stability. A variety of biophysical methods were employed to unveil the mechanisms underlying the unique features of Cut190, which included the regulation of its activity and thermal stability by Ca2+. Ca2+ association and dissociation can change the enzyme conformation to regulate catalytic activity. Weak metal-ion binding would be required for the naïve conformational change of Cut190, while maintaining its fluctuation, to “switch” the enzyme on and off. The activity of Cut190 is regulated by the weak Ca2+ binding to the specific site, Site 1, while thermal stability is mainly regulated by binding to another Site 2, where a disulfide bond could be introduced to increase the stability. Recent results on the structure-activity relationship of engineered Cut190 are reviewed, including the application for PET depolymerization by enzymes.
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Affiliation(s)
- Masayuki Oda
- Graduate School of Life and Environmental Sciences, Kyoto Prefectural University, Kyoto 606-8522, Japan
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16
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Nikolaivits E, Pantelic B, Azeem M, Taxeidis G, Babu R, Topakas E, Brennan Fournet M, Nikodinovic-Runic J. Progressing Plastics Circularity: A Review of Mechano-Biocatalytic Approaches for Waste Plastic (Re)valorization. Front Bioeng Biotechnol 2021; 9:696040. [PMID: 34239864 PMCID: PMC8260098 DOI: 10.3389/fbioe.2021.696040] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 05/28/2021] [Indexed: 01/10/2023] Open
Abstract
Inspirational concepts, and the transfer of analogs from natural biology to science and engineering, has produced many excellent technologies to date, spanning vaccines to modern architectural feats. This review highlights that answers to the pressing global petroleum-based plastic waste challenges, can be found within the mechanics and mechanisms natural ecosystems. Here, a suite of technological and engineering approaches, which can be implemented to operate in tandem with nature's prescription for regenerative material circularity, is presented as a route to plastics sustainability. A number of mechanical/green chemical (pre)treatment methodologies, which simulate natural weathering and arthropodal dismantling activities are reviewed, including: mechanical milling, reactive extrusion, ultrasonic-, UV- and degradation using supercritical CO2. Akin to natural mechanical degradation, the purpose of the pretreatments is to render the plastic materials more amenable to microbial and biocatalytic activities, to yield effective depolymerization and (re)valorization. While biotechnological based degradation and depolymerization of both recalcitrant and bioplastics are at a relatively early stage of development, the potential for acceleration and expedition of valuable output monomers and oligomers yields is considerable. To date a limited number of independent mechano-green chemical approaches and a considerable and growing number of standalone enzymatic and microbial degradation studies have been reported. A convergent strategy, one which forges mechano-green chemical treatments together with the enzymatic and microbial actions, is largely lacking at this time. An overview of the reported microbial and enzymatic degradations of petroleum-based synthetic polymer plastics, specifically: low-density polyethylene (LDPE), high-density polyethylene (HDPE), polystyrene (PS), polyethylene terephthalate (PET), polyurethanes (PU) and polycaprolactone (PCL) and selected prevalent bio-based or bio-polymers [polylactic acid (PLA), polyhydroxyalkanoates (PHAs) and polybutylene succinate (PBS)], is detailed. The harvesting of depolymerization products to produce new materials and higher-value products is also a key endeavor in effectively completing the circle for plastics. Our challenge is now to effectively combine and conjugate the requisite cross disciplinary approaches and progress the essential science and engineering technologies to categorically complete the life-cycle for plastics.
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Affiliation(s)
- Efstratios Nikolaivits
- Industrial Biotechnology & Biocatalysis Group, Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, Athens, Greece
| | - Brana Pantelic
- Eco-Biotechnology & Drug Development Group, Laboratory for Microbial Molecular Genetics and Ecology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
| | | | - George Taxeidis
- Industrial Biotechnology & Biocatalysis Group, Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, Athens, Greece
| | - Ramesh Babu
- AMBER Centre, CRANN Institute, School of Chemistry, Trinity College Dublin, Dublin, Ireland
| | - Evangelos Topakas
- Industrial Biotechnology & Biocatalysis Group, Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, Athens, Greece
| | | | - Jasmina Nikodinovic-Runic
- Eco-Biotechnology & Drug Development Group, Laboratory for Microbial Molecular Genetics and Ecology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia
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17
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Meng X, Yang L, Liu H, Li Q, Xu G, Zhang Y, Guan F, Zhang Y, Zhang W, Wu N, Tian J. Protein engineering of stable IsPETase for PET plastic degradation by Premuse. Int J Biol Macromol 2021; 180:667-676. [PMID: 33753197 DOI: 10.1016/j.ijbiomac.2021.03.058] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 03/09/2021] [Accepted: 03/10/2021] [Indexed: 11/25/2022]
Abstract
Poly(ethylene terephthalate) (PET) is used widely by human beings, but is very difficult to degrade. Up to now, the PET degradation effect of PETase from Ideonella sakaiensis 201-F6 (IsPETase) variants with low stability and activity was not ideal. In this study, a mutation design tool, Premuse, was developed to integrate the sequence alignment and quantitative selection of the preferred mutations based on natural sequence evolution. Ten single point mutants were selected from 1486 homologous sequences using Premuse, and then two mutations (W159H and F229Y) with improved stability were screened from them. The derived double point mutant, W159H/F229Y, exhibited a strikingly enhanced enzymatic performance. Its Tm and catalytic efficiency values (kcat/Km) respectively increased by 10.4 °C and 2.0-fold using p-NPP as the substrate compared with wild type. The degradation activity for amorphous PET was increased by almost 40-fold in comparison with wild type at 40 °C in 24 h. Additionally, the variant could catalyze biodegradation of PET bottle preform at a mean rate of 23.4 mgPET/h/mgenzyme. This study allowed us to design the mutation more efficiently, and provides a tool for achieving biodegradation of PET pollution under mild natural environments.
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Affiliation(s)
- Xiangxi Meng
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Lixin Yang
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Hanqing Liu
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Qingbin Li
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China; State Key Laboratory of Microbial Technology, Shandong University, Qingdao, China
| | - Guoshun Xu
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Yan Zhang
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China; College of Food Science and Technology, Agricultural University of Hebei, Baoding, Hebei Province 071001, China
| | - Feifei Guan
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Yuhong Zhang
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Wei Zhang
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Ningfeng Wu
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
| | - Jian Tian
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
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18
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Cui Y, Chen Y, Liu X, Dong S, Tian Y, Qiao Y, Mitra R, Han J, Li C, Han X, Liu W, Chen Q, Wei W, Wang X, Du W, Tang S, Xiang H, Liu H, Liang Y, Houk KN, Wu B. Computational Redesign of a PETase for Plastic Biodegradation under Ambient Condition by the GRAPE Strategy. ACS Catal 2021. [DOI: 10.1021/acscatal.0c05126] [Citation(s) in RCA: 97] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Yinglu Cui
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101,China
| | - Yanchun Chen
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101,China
- University of Chinese Academy of Sciences, Beijing 100049,China
| | - Xinyue Liu
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101,China
- School of Life Sciences, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230052,China
| | - Saijun Dong
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101,China
| | - Yu’e Tian
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101,China
| | - Yuxin Qiao
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101,China
| | - Ruchira Mitra
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101,China
- University of Chinese Academy of Sciences, Beijing 100049,China
| | - Jing Han
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101,China
| | - Chunli Li
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101,China
| | - Xu Han
- Industrial Enzymes National Engineering Laboratory, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308,China
| | - Weidong Liu
- Industrial Enzymes National Engineering Laboratory, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin 300308,China
| | - Quan Chen
- School of Life Sciences, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230052,China
| | - Wangqing Wei
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023,China
| | - Xin Wang
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023,China
| | - Wenbin Du
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101,China
| | - Shuangyan Tang
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101,China
| | - Hua Xiang
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101,China
| | - Haiyan Liu
- School of Life Sciences, Hefei National Laboratory for Physical Sciences at the Microscale, University of Science and Technology of China, Hefei 230052,China
| | - Yong Liang
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023,China
| | - Kendall N. Houk
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles 90095, California, United States
| | - Bian Wu
- CAS Key Laboratory of Microbial Physiological and Metabolic Engineering, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101,China
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19
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Sanders D, Grunden A, Dunn RR. A review of clothing microbiology: the history of clothing and the role of microbes in textiles. Biol Lett 2021; 17:20200700. [PMID: 33435848 PMCID: PMC7876606 DOI: 10.1098/rsbl.2020.0700] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 12/14/2020] [Indexed: 12/11/2022] Open
Abstract
Humans have worn clothing for thousands of years, and since its invention, clothing has evolved from its simple utilitarian function for survival to become an integral part of society. While much consideration has been given to the broad environmental impacts of the textile and laundering industries, little is known about the impact wearing clothing has had on the human microbiome, particularly that of the skin, despite our long history with clothing. This review discusses the history of clothing and the evolution of textiles, what is and is not known about microbial persistence on and degradation of various fibres, and what opportunities for the industrial and environmental application of clothing microbiology exist for the future.
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Affiliation(s)
- Deaja Sanders
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA
| | - Amy Grunden
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA
| | - Robert R. Dunn
- Department of Applied Ecology, North Carolina State University, Raleigh, NC 27695, USA
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20
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Mohanan N, Montazer Z, Sharma PK, Levin DB. Microbial and Enzymatic Degradation of Synthetic Plastics. Front Microbiol 2020; 11:580709. [PMID: 33324366 PMCID: PMC7726165 DOI: 10.3389/fmicb.2020.580709] [Citation(s) in RCA: 278] [Impact Index Per Article: 69.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 10/20/2020] [Indexed: 12/13/2022] Open
Abstract
Synthetic plastics are pivotal in our current lifestyle and therefore, its accumulation is a major concern for environment and human health. Petroleum-derived (petro-)polymers such as polyethylene (PE), polyethylene terephthalate (PET), polyurethane (PU), polystyrene (PS), polypropylene (PP), and polyvinyl chloride (PVC) are extremely recalcitrant to natural biodegradation pathways. Some microorganisms with the ability to degrade petro-polymers under in vitro conditions have been isolated and characterized. In some cases, the enzymes expressed by these microbes have been cloned and sequenced. The rate of polymer biodegradation depends on several factors including chemical structures, molecular weights, and degrees of crystallinity. Polymers are large molecules having both regular crystals (crystalline region) and irregular groups (amorphous region), where the latter provides polymers with flexibility. Highly crystalline polymers like polyethylene (95%), are rigid with a low capacity to resist impacts. PET-based plastics possess a high degree of crystallinity (30-50%), which is one of the principal reasons for their low rate of microbial degradation, which is projected to take more than 50 years for complete degraded in the natural environment, and hundreds of years if discarded into the oceans, due to their lower temperature and oxygen availability. The enzymatic degradation occurs in two stages: adsorption of enzymes on the polymer surface, followed by hydro-peroxidation/hydrolysis of the bonds. The sources of plastic-degrading enzymes can be found in microorganisms from various environments as well as digestive intestine of some invertebrates. Microbial and enzymatic degradation of waste petro-plastics is a promising strategy for depolymerization of waste petro-plastics into polymer monomers for recycling, or to covert waste plastics into higher value bioproducts, such as biodegradable polymers via mineralization. The objective of this review is to outline the advances made in the microbial degradation of synthetic plastics and, overview the enzymes involved in biodegradation.
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Affiliation(s)
- Nisha Mohanan
- Department of Biosystems Engineering, University of Manitoba, Winnipeg, MB, Canada
| | - Zahra Montazer
- Faculty of Food Engineering, The Educational Complex of Agriculture and Animal Science, Torbat-e-jam, Iran
| | - Parveen K. Sharma
- Department of Biosystems Engineering, University of Manitoba, Winnipeg, MB, Canada
| | - David B. Levin
- Department of Biosystems Engineering, University of Manitoba, Winnipeg, MB, Canada
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21
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Carr CM, Clarke DJ, Dobson ADW. Microbial Polyethylene Terephthalate Hydrolases: Current and Future Perspectives. Front Microbiol 2020; 11:571265. [PMID: 33262744 PMCID: PMC7686037 DOI: 10.3389/fmicb.2020.571265] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 10/19/2020] [Indexed: 12/18/2022] Open
Abstract
Plastic has rapidly transformed our world, with many aspects of human life now relying on a variety of plastic materials. Biological plastic degradation, which employs microorganisms and their degradative enzymes, has emerged as one way to address the unforeseen consequences of the waste streams that have resulted from mass plastic production. The focus of this review is microbial hydrolase enzymes which have been found to act on polyethylene terephthalate (PET) plastic. The best characterized examples are discussed together with the use of genomic and protein engineering technologies to obtain PET hydrolase enzymes for different applications. In addition, the obstacles which are currently limiting the development of efficient PET bioprocessing are presented. By continuing to study the possible mechanisms and the structural elements of key enzymes involved in microbial PET hydrolysis, and by assessing the ability of PET hydrolase enzymes to work under practical conditions, this research will help inform large-scale waste management operations. Finally, the contribution of microbial PET hydrolases in creating a potential circular PET economy will be explored. This review combines the current knowledge on enzymatic PET processing with proposed strategies for optimization and use, to help clarify the next steps in addressing pollution by PET and other plastics.
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Affiliation(s)
- Clodagh M. Carr
- School of Microbiology, University College Cork, Cork, Ireland
| | - David J. Clarke
- School of Microbiology, University College Cork, Cork, Ireland
| | - Alan D. W. Dobson
- School of Microbiology, University College Cork, Cork, Ireland
- SSPC-SFI Research Centre for Pharmaceuticals, University College Cork, Cork, Ireland
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22
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Zimmermann W. Biocatalytic recycling of polyethylene terephthalate plastic. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2020; 378:20190273. [PMID: 32623985 PMCID: PMC7422893 DOI: 10.1098/rsta.2019.0273] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/19/2019] [Indexed: 05/20/2023]
Abstract
The global production of plastics made from non-renewable fossil feedstocks has grown more than 20-fold since 1964. While more than eight billion tons of plastics have been produced until today, only a small fraction is currently collected for recycling and large amounts of plastic waste are ending up in landfills and in the oceans. Pollution caused by accumulating plastic waste in the environment has become worldwide a serious problem. Synthetic polyesters such as polyethylene terephthalate (PET) have widespread use in food packaging materials, beverage bottles, coatings and fibres. Recently, it has been shown that post-consumer PET can be hydrolysed by microbial enzymes at mild reaction conditions in aqueous media. In a circular plastics economy, the resulting monomers can be recovered and re-used to manufacture PET products or other chemicals without depleting fossil feedstocks and damaging the environment. The enzymatic degradation of post-consumer plastics thereby represents an innovative, environmentally benign and sustainable alternative to conventional recycling processes. By the construction of powerful biocatalysts employing protein engineering techniques, a biocatalytic recycling of PET can be further developed towards industrial applications. This article is part of a discussion meeting issue 'Science to enable the circular economy'.
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23
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Danso D, Chow J, Streit WR. Plastics: Environmental and Biotechnological Perspectives on Microbial Degradation. Appl Environ Microbiol 2019; 85:e01095-19. [PMID: 31324632 PMCID: PMC6752018 DOI: 10.1128/aem.01095-19] [Citation(s) in RCA: 299] [Impact Index Per Article: 59.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Plastics are widely used in the global economy, and each year, at least 350 to 400 million tons are being produced. Due to poor recycling and low circular use, millions of tons accumulate annually in terrestrial or marine environments. Today it has become clear that plastic causes adverse effects in all ecosystems and that microplastics are of particular concern to our health. Therefore, recent microbial research has addressed the question of if and to what extent microorganisms can degrade plastics in the environment. This review summarizes current knowledge on microbial plastic degradation. Enzymes available act mainly on the high-molecular-weight polymers of polyethylene terephthalate (PET) and ester-based polyurethane (PUR). Unfortunately, the best PUR- and PET-active enzymes and microorganisms known still have moderate turnover rates. While many reports describing microbial communities degrading chemical additives have been published, no enzymes acting on the high-molecular-weight polymers polystyrene, polyamide, polyvinylchloride, polypropylene, ether-based polyurethane, and polyethylene are known. Together, these polymers comprise more than 80% of annual plastic production. Thus, further research is needed to significantly increase the diversity of enzymes and microorganisms acting on these polymers. This can be achieved by tapping into the global metagenomes of noncultivated microorganisms and dark matter proteins. Only then can novel biocatalysts and organisms be delivered that allow rapid degradation, recycling, or value-added use of the vast majority of most human-made polymers.
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Affiliation(s)
- Dominik Danso
- Department of Microbiology and Biotechnology, University of Hamburg, Hamburg, Germany
| | - Jennifer Chow
- Department of Microbiology and Biotechnology, University of Hamburg, Hamburg, Germany
| | - Wolfgang R Streit
- Department of Microbiology and Biotechnology, University of Hamburg, Hamburg, Germany
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24
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Taniguchi I, Yoshida S, Hiraga K, Miyamoto K, Kimura Y, Oda K. Biodegradation of PET: Current Status and Application Aspects. ACS Catal 2019. [DOI: 10.1021/acscatal.8b05171] [Citation(s) in RCA: 207] [Impact Index Per Article: 41.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Ikuo Taniguchi
- Department of Polymer Science, Faculty of Textile Science, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Shosuke Yoshida
- Department of Applied Biology, Faculty of Textile Science, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
- Department of Biosciences and Informatics, Keio University, 3-14-1 Hiyoshi,
Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan
| | - Kazumi Hiraga
- Department of Applied Biology, Faculty of Textile Science, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Kenji Miyamoto
- Department of Biosciences and Informatics, Keio University, 3-14-1 Hiyoshi,
Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan
| | - Yoshiharu Kimura
- Department of Polymer Science, Faculty of Textile Science, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Kohei Oda
- Department of Applied Biology, Faculty of Textile Science, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
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25
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Current knowledge on enzymatic PET degradation and its possible application to waste stream management and other fields. Appl Microbiol Biotechnol 2019; 103:4253-4268. [PMID: 30957199 PMCID: PMC6505623 DOI: 10.1007/s00253-019-09717-y] [Citation(s) in RCA: 235] [Impact Index Per Article: 47.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 02/20/2019] [Accepted: 02/22/2019] [Indexed: 11/21/2022]
Abstract
Enzymatic hydrolysis of polyethylene terephthalate (PET) has been the subject of extensive previous research that can be grouped into two categories, viz. enzymatic surface modification of polyester fibers and management of PET waste by enzymatic hydrolysis. Different enzymes with rather specific properties are required for these two processes. Enzymatic surface modification is possible with several hydrolases, such as lipases, carboxylesterases, cutinases, and proteases. These enzymes should be designated as PET surface–modifying enzymes and should not degrade the building blocks of PET but should hydrolyze the surface polymer chain so that the intensity of PET is not weakened. Conversely, management of PET waste requires substantial degradation of the building blocks of PET; therefore, only a limited number of cutinases have been recognized as PET hydrolases since the first PET hydrolase was discovered by Müller et al. (Macromol Rapid Commun 26:1400–1405, 2005). Here, we introduce current knowledge on enzymatic degradation of PET with a focus on the key class of enzymes, PET hydrolases, pertaining to the definition of enzymatic requirements for PET hydrolysis, structural analyses of PET hydrolases, and the reaction mechanisms. This review gives a deep insight into the structural basis and dynamics of PET hydrolases based on the recent progress in X-ray crystallography. Based on the knowledge accumulated to date, we discuss the potential for PET hydrolysis applications, such as in designing waste stream management.
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Biodegradation of Microplastic Derived from Poly(ethylene terephthalate) with Bacterial Whole-Cell Biocatalysts. Polymers (Basel) 2018; 10:polym10121326. [PMID: 30961251 PMCID: PMC6401706 DOI: 10.3390/polym10121326] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 11/23/2018] [Accepted: 11/23/2018] [Indexed: 01/18/2023] Open
Abstract
At present, the pollution of microplastic directly threatens ecology, food safety and even human health. Polyethylene terephthalate (PET) is one of the most common of microplastics. In this study, the micro-size PET particles were employed as analog of microplastic. The engineered strain, which can growth with PET as sole carbon source, was used as biocatalyst for biodegradation of PET particles. A combinatorial processing based on whole-cell biocatalysts was constructed for biodegradation of PET. Compared with enzymes, the products can be used by strain growth and do not accumulated in culture solution. Thus, feedback inhibition of products can be avoided. When PET was treated with the alkaline strain under high pH conditions, the product concentration was higher and the size of PET particles decreased dramatically than that of the biocatalyst under neutral conditions. This shows that the method of combined processing of alkali and organisms is more efficient for biodegradation of PET. The novel approach of combinatorial processing of PET based on whole-cell biocatalysis provides an attractive avenue for the biodegradation of micplastics.
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Wei R, Zimmermann W. Microbial enzymes for the recycling of recalcitrant petroleum-based plastics: how far are we? Microb Biotechnol 2017; 10:1308-1322. [PMID: 28371373 PMCID: PMC5658625 DOI: 10.1111/1751-7915.12710] [Citation(s) in RCA: 336] [Impact Index Per Article: 48.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 03/02/2017] [Accepted: 03/06/2017] [Indexed: 01/25/2023] Open
Abstract
Petroleum-based plastics have replaced many natural materials in their former applications. With their excellent properties, they have found widespread uses in almost every area of human life. However, the high recalcitrance of many synthetic plastics results in their long persistence in the environment, and the growing amount of plastic waste ending up in landfills and in the oceans has become a global concern. In recent years, a number of microbial enzymes capable of modifying or degrading recalcitrant synthetic polymers have been identified. They are emerging as candidates for the development of biocatalytic plastic recycling processes, by which valuable raw materials can be recovered in an environmentally sustainable way. This review is focused on microbial biocatalysts involved in the degradation of the synthetic plastics polyethylene, polystyrene, polyurethane and polyethylene terephthalate (PET). Recent progress in the application of polyester hydrolases for the recovery of PET building blocks and challenges for the application of these enzymes in alternative plastic waste recycling processes will be discussed.
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Affiliation(s)
- Ren Wei
- Department of Microbiology and Bioprocess TechnologyInstitute of BiochemistryLeipzig UniversityJohannisallee 21‐2304103LeipzigGermany
| | - Wolfgang Zimmermann
- Department of Microbiology and Bioprocess TechnologyInstitute of BiochemistryLeipzig UniversityJohannisallee 21‐2304103LeipzigGermany
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Haernvall K, Zitzenbacher S, Yamamoto M, Schick MB, Ribitsch D, Guebitz GM. Polyol Structure and Ionic Moieties Influence the Hydrolytic Stability and Enzymatic Hydrolysis of Bio-Based 2,5-Furandicarboxylic Acid (FDCA) Copolyesters. Polymers (Basel) 2017; 9:polym9090403. [PMID: 30965704 PMCID: PMC6418894 DOI: 10.3390/polym9090403] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 08/13/2017] [Accepted: 08/23/2017] [Indexed: 11/17/2022] Open
Abstract
A series of copolyesters based on furanic acid and sulfonated isophthalic acid with various polyols were synthetized and their susceptibility to enzymatic hydrolysis by cutinase 1 from Thermobifida cellulosilytica (Thc_Cut1) investigated. All copolyesters consisted of 30 mol % 5-sulfoisophthalate units (NaSIP) and 70 mol % 2,5-furandicarboxylic acid (FDCA), while the polyol component was varied, including 1,2-ethanediol, 1,4-butanediol, 1,8-octanediol, diethylene glycol, triethylene glycol, or tetraethylene glycol. The composition of the copolyesters was confirmed by 1H-NMR and the number average molecular weight (Mn) was determined by GPC to range from 2630 to 8030 g/mol. A DSC analysis revealed glass-transition temperatures (Tg) from 84 to 6 °C, which were decreasing with increasing diol chain length. The crystallinity was below 1% for all polyesters. The hydrolytic stability increased with the chain length of the alkyl diol unit, while it was generally higher for the ether diol units. Thc_Cut1 was able to hydrolyze all of the copolyesters containing alkyl diols ranging from two to eight carbon chain lengths, while the highest activities were detected for the shorter chain lengths with an amount of 13.6 ± 0.7 mM FDCA released after 72 h of incubation at 50 °C. Faster hydrolysis was observed when replacing an alkyl diol by ether diols, as indicated, e.g., by a fivefold higher release of FDCA for triethylene glycol when compared to 1,8-octanediol. A positive influence of introducing ionic phthalic acid was observed while the enzyme preferentially cleaved ester bonds associated to the non-charged building blocks.
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Affiliation(s)
- Karolina Haernvall
- ACIB: Austrian Centre of Industrial Biotechnology GmbH, Konrad Lorenz Strasse 20, 3430 Tulln an der Donau, Austria.
| | - Sabine Zitzenbacher
- ACIB: Austrian Centre of Industrial Biotechnology GmbH, Konrad Lorenz Strasse 20, 3430 Tulln an der Donau, Austria.
| | - Motonori Yamamoto
- BASF SE, Carl-Bosch-Straße 38, 67056 Ludwigshafen am Rhein, Germany.
| | | | - Doris Ribitsch
- ACIB: Austrian Centre of Industrial Biotechnology GmbH, Konrad Lorenz Strasse 20, 3430 Tulln an der Donau, Austria.
| | - Georg M Guebitz
- ACIB: Austrian Centre of Industrial Biotechnology GmbH, Konrad Lorenz Strasse 20, 3430 Tulln an der Donau, Austria.
- BOKU, University of Natural Resources and Life Sciences, Institute for Environmental Biotechnology, Konrad Lorenz Strasse 20, 3430 Tulln an der Donau, Austria.
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Wei R, Zimmermann W. Biocatalysis as a green route for recycling the recalcitrant plastic polyethylene terephthalate. Microb Biotechnol 2017; 10:1302-1307. [PMID: 28401691 PMCID: PMC5658586 DOI: 10.1111/1751-7915.12714] [Citation(s) in RCA: 148] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 03/16/2017] [Accepted: 03/16/2017] [Indexed: 01/26/2023] Open
Abstract
Biocatalysis can enable a closed‐loop recycling of post‐consumer PET waste.
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Affiliation(s)
- Ren Wei
- Department of Microbiology and Bioprocess Technology, Institute of Biochemistry, Leipzig University, Johannisallee 21-23, 04103, Leipzig, Germany
| | - Wolfgang Zimmermann
- Department of Microbiology and Bioprocess Technology, Institute of Biochemistry, Leipzig University, Johannisallee 21-23, 04103, Leipzig, Germany
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Müller CA, Perz V, Provasnek C, Quartinello F, Guebitz GM, Berg G. Discovery of Polyesterases from Moss-Associated Microorganisms. Appl Environ Microbiol 2017; 83:e02641-16. [PMID: 27940546 PMCID: PMC5288828 DOI: 10.1128/aem.02641-16] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Accepted: 12/07/2016] [Indexed: 11/20/2022] Open
Abstract
The growing pollution of the environment with plastic debris is a global threat which urgently requires biotechnological solutions. Enzymatic recycling not only prevents pollution but also would allow recovery of valuable building blocks. Therefore, we explored the existence of microbial polyesterases in microbial communities associated with the Sphagnum magellanicum moss, a key species within unexploited bog ecosystems. This resulted in the identification of six novel esterases, which were isolated, cloned, and heterologously expressed in Escherichia coli The esterases were found to hydrolyze the copolyester poly(butylene adipate-co-butylene terephthalate) (PBAT) and the oligomeric model substrate bis[4-(benzoyloxy)butyl] terephthalate (BaBTaBBa). Two promising polyesterase candidates, EstB3 and EstC7, which clustered in family VIII of bacterial lipolytic enzymes, were purified and characterized using the soluble esterase substrate p-nitrophenyl butyrate (Km values of 46.5 and 3.4 μM, temperature optima of 48°C and 50°C, and pH optima of 7.0 and 8.5, respectively). In particular, EstC7 showed outstanding activity and a strong preference for hydrolysis of the aromatic ester bond in PBAT. Our study highlights the potential of plant-associated microbiomes from extreme natural ecosystems as a source for novel hydrolytic enzymes hydrolyzing polymeric compounds. IMPORTANCE In this study, we describe the discovery and analysis of new enzymes from microbial communities associated with plants (moss). The recovered enzymes show the ability to hydrolyze not only common esterase substrates but also the synthetic polyester poly(butylene adipate-co-butylene terephthalate), which is a common material employed in biodegradable plastics. The widespread use of such synthetic polyesters in industry and society requires the development of new sustainable technological solutions for their recycling. The discovered enzymes have the potential to be used as catalysts for selective recovery of valuable building blocks from this material.
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Affiliation(s)
- Christina Andrea Müller
- Institute of Environmental Biotechnology, Graz University of Technology, Graz, Austria
- ACIB GmbH, Graz, Austria
| | | | - Christoph Provasnek
- Institute of Environmental Biotechnology, Graz University of Technology, Graz, Austria
- ACIB GmbH, Graz, Austria
| | - Felice Quartinello
- Institute of Environmental Biotechnology, University of Natural Resources and Life Sciences, Tulln an der Donau, Austria
| | - Georg M Guebitz
- ACIB GmbH, Tulln an der Donau, Austria
- Institute of Environmental Biotechnology, University of Natural Resources and Life Sciences, Tulln an der Donau, Austria
| | - Gabriele Berg
- Institute of Environmental Biotechnology, Graz University of Technology, Graz, Austria
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Yoshida S, Hiraga K, Takehana T, Taniguchi I, Yamaji H, Maeda Y, Toyohara K, Miyamoto K, Kimura Y, Oda K. Response to Comment on "A bacterium that degrades and assimilates poly(ethylene terephthalate)". Science 2016; 353:759. [DOI: 10.1126/science.aaf8625] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2016] [Accepted: 07/14/2016] [Indexed: 11/02/2022]
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Then J, Wei R, Oeser T, Gerdts A, Schmidt J, Barth M, Zimmermann W. A disulfide bridge in the calcium binding site of a polyester hydrolase increases its thermal stability and activity against polyethylene terephthalate. FEBS Open Bio 2016; 6:425-32. [PMID: 27419048 PMCID: PMC4856421 DOI: 10.1002/2211-5463.12053] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 02/09/2016] [Accepted: 03/02/2016] [Indexed: 11/29/2022] Open
Abstract
Elevated reaction temperatures are crucial for the efficient enzymatic degradation of polyethylene terephthalate (PET). A disulfide bridge was introduced to the polyester hydrolase TfCut2 to substitute its calcium binding site. The melting point of the resulting variant increased to 94.7 °C (wild‐type TfCut2: 69.8 °C) and its half‐inactivation temperature to 84.6 °C (TfCut2: 67.3 °C). The variant D204C‐E253C‐D174R obtained by introducing further mutations at vicinal residues showed a temperature optimum between 75 and 80 °C compared to 65 and 70 °C of the wild‐type enzyme. The variant caused a weight loss of PET films of 25.0 ± 0.8% (TfCut2: 0.3 ± 0.1%) at 70 °C after a reaction time of 48 h. The results demonstrate that a highly efficient and calcium‐independent thermostable polyester hydrolase can be obtained by replacing its calcium binding site with a disulfide bridge.
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Affiliation(s)
- Johannes Then
- Department of Microbiology and Bioprocess Technology Institute of Biochemistry Leipzig University Germany
| | - Ren Wei
- Department of Microbiology and Bioprocess Technology Institute of Biochemistry Leipzig University Germany
| | - Thorsten Oeser
- Department of Microbiology and Bioprocess Technology Institute of Biochemistry Leipzig University Germany
| | - André Gerdts
- Department of Microbiology and Bioprocess Technology Institute of Biochemistry Leipzig University Germany
| | - Juliane Schmidt
- Department of Microbiology and Bioprocess Technology Institute of Biochemistry Leipzig University Germany
| | - Markus Barth
- Department of Microbiology and Bioprocess Technology Institute of Biochemistry Leipzig University Germany
| | - Wolfgang Zimmermann
- Department of Microbiology and Bioprocess Technology Institute of Biochemistry Leipzig University Germany
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Yoshida S, Hiraga K, Takehana T, Taniguchi I, Yamaji H, Maeda Y, Toyohara K, Miyamoto K, Kimura Y, Oda K. A bacterium that degrades and assimilates poly(ethylene terephthalate). Science 2016; 351:1196-9. [DOI: 10.1126/science.aad6359] [Citation(s) in RCA: 1080] [Impact Index Per Article: 135.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Wei R, Oeser T, Schmidt J, Meier R, Barth M, Then J, Zimmermann W. Engineered bacterial polyester hydrolases efficiently degrade polyethylene terephthalate due to relieved product inhibition. Biotechnol Bioeng 2016; 113:1658-65. [DOI: 10.1002/bit.25941] [Citation(s) in RCA: 119] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Revised: 01/11/2016] [Accepted: 01/19/2016] [Indexed: 11/11/2022]
Affiliation(s)
- Ren Wei
- Department of Microbiology and Bioprocess Technology; Institute of Biochemistry; Leipzig University; Johannisallee 21-23 04103 Leipzig Germany
| | - Thorsten Oeser
- Department of Microbiology and Bioprocess Technology; Institute of Biochemistry; Leipzig University; Johannisallee 21-23 04103 Leipzig Germany
| | - Juliane Schmidt
- Department of Microbiology and Bioprocess Technology; Institute of Biochemistry; Leipzig University; Johannisallee 21-23 04103 Leipzig Germany
| | - René Meier
- Department of Biochemistry and Bioorganic Chemistry; Institute of Biochemistry; Leipzig University; Leipzig Germany
| | - Markus Barth
- Department of Microbiology and Bioprocess Technology; Institute of Biochemistry; Leipzig University; Johannisallee 21-23 04103 Leipzig Germany
| | - Johannes Then
- Department of Microbiology and Bioprocess Technology; Institute of Biochemistry; Leipzig University; Johannisallee 21-23 04103 Leipzig Germany
| | - Wolfgang Zimmermann
- Department of Microbiology and Bioprocess Technology; Institute of Biochemistry; Leipzig University; Johannisallee 21-23 04103 Leipzig Germany
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Then J, Wei R, Oeser T, Barth M, Belisário-Ferrari MR, Schmidt J, Zimmermann W. Ca2+and Mg2+binding site engineering increases the degradation of polyethylene terephthalate films by polyester hydrolases fromThermobifida fusca. Biotechnol J 2015; 10:592-8. [DOI: 10.1002/biot.201400620] [Citation(s) in RCA: 83] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Revised: 11/21/2014] [Accepted: 12/22/2014] [Indexed: 11/06/2022]
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Structural basis for the Ca(2+)-enhanced thermostability and activity of PET-degrading cutinase-like enzyme from Saccharomonospora viridis AHK190. Appl Microbiol Biotechnol 2014; 99:4297-307. [PMID: 25492421 DOI: 10.1007/s00253-014-6272-8] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2014] [Revised: 11/22/2014] [Accepted: 11/25/2014] [Indexed: 01/06/2023]
Abstract
A cutinase-like enzyme from Saccharomonospora viridis AHK190, Cut190, hydrolyzes the inner block of polyethylene terephthalate (PET); this enzyme is a member of the lipase family, which contains an α/β hydrolase fold and a Ser-His-Asp catalytic triad. The thermostability and activity of Cut190 are enhanced by high concentrations of calcium ions, which is essential for the efficient enzymatic hydrolysis of amorphous PET. Although Ca(2+)-induced thermostabilization and activation of enzymes have been well explored in α-amylases, the mechanism for PET-degrading cutinase-like enzymes remains poorly understood. We focused on the mechanisms by which Ca(2+) enhances these properties, and we determined the crystal structures of a Cut190 S226P mutant (Cut190(S226P)) in the Ca(2+)-bound and free states at 1.75 and 1.45 Å resolution, respectively. Based on the crystallographic data, a Ca(2+) ion was coordinated by four residues within loop regions (the Ca(2+) site) and two water molecules in a tetragonal bipyramidal array. Furthermore, the binding of Ca(2+) to Cut190(S226P) induced large conformational changes in three loops, which were accompanied by the formation of additional interactions. The binding of Ca(2+) not only stabilized a region that is flexible in the Ca(2+)-free state but also modified the substrate-binding groove by stabilizing an open conformation that allows the substrate to bind easily. Thus, our study explains the structural basis of Ca(2+)-enhanced thermostability and activity in PET-degrading cutinase-like enzyme for the first time and found that the inactive state of Cut190(S226P) is activated by a conformational change in the active-site sealing residue, F106.
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Wei R, Oeser T, Then J, Kühn N, Barth M, Schmidt J, Zimmermann W. Functional characterization and structural modeling of synthetic polyester-degrading hydrolases from Thermomonospora curvata. AMB Express 2014; 4:44. [PMID: 25405080 PMCID: PMC4231364 DOI: 10.1186/s13568-014-0044-9] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2014] [Accepted: 04/27/2014] [Indexed: 01/01/2023] Open
Abstract
Thermomonospora curvata is a thermophilic actinomycete phylogenetically related to Thermobifida fusca that produces extracellular hydrolases capable of degrading synthetic polyesters. Analysis of the genome of T. curvata DSM43183 revealed two genes coding for putative polyester hydrolases Tcur1278 and Tcur0390 sharing 61% sequence identity with the T. fusca enzymes. Mature proteins of Tcur1278 and Tcur0390 were cloned and expressed in Escherichia coli TOP10. Tcur1278 and Tcur0390 exhibited an optimal reaction temperature against p-nitrophenyl butyrate at 60°C and 55°C, respectively. The optimal pH for both enzymes was determined at pH 8.5. Tcur1278 retained more than 80% and Tcur0390 less than 10% of their initial activity following incubation for 60 min at 55°C. Tcur0390 showed a higher hydrolytic activity against poly(ε-caprolactone) and polyethylene terephthalate (PET) nanoparticles compared to Tcur1278 at reaction temperatures up to 50°C. At 55°C and 60°C, hydrolytic activity against PET nanoparticles was only detected with Tcur1278. In silico modeling of the polyester hydrolases and docking with a model substrate composed of two repeating units of PET revealed the typical fold of α/β serine hydrolases with an exposed catalytic triad. Molecular dynamics simulations confirmed the superior thermal stability of Tcur1278 considered as the main reason for its higher hydrolytic activity on PET.
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Affiliation(s)
- Ren Wei
- Department of Microbiology and Bioprocess Technology, Institute of Biochemistry, University of Leipzig, Johannisallee 21-23, Leipzig, D-04103, Germany
| | - Thorsten Oeser
- Department of Microbiology and Bioprocess Technology, Institute of Biochemistry, University of Leipzig, Johannisallee 21-23, Leipzig, D-04103, Germany
| | - Johannes Then
- Department of Microbiology and Bioprocess Technology, Institute of Biochemistry, University of Leipzig, Johannisallee 21-23, Leipzig, D-04103, Germany
| | - Nancy Kühn
- Department of Microbiology and Bioprocess Technology, Institute of Biochemistry, University of Leipzig, Johannisallee 21-23, Leipzig, D-04103, Germany
| | - Markus Barth
- Department of Microbiology and Bioprocess Technology, Institute of Biochemistry, University of Leipzig, Johannisallee 21-23, Leipzig, D-04103, Germany
| | - Juliane Schmidt
- Department of Microbiology and Bioprocess Technology, Institute of Biochemistry, University of Leipzig, Johannisallee 21-23, Leipzig, D-04103, Germany
| | - Wolfgang Zimmermann
- Department of Microbiology and Bioprocess Technology, Institute of Biochemistry, University of Leipzig, Johannisallee 21-23, Leipzig, D-04103, Germany
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Two novel class II hydrophobins from Trichoderma spp. stimulate enzymatic hydrolysis of poly(ethylene terephthalate) when expressed as fusion proteins. Appl Environ Microbiol 2013; 79:4230-8. [PMID: 23645195 DOI: 10.1128/aem.01132-13] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Poly(ethylene terephthalate) (PET) can be functionalized and/or recycled via hydrolysis by microbial cutinases. The rate of hydrolysis is however low. Here, we tested whether hydrophobins (HFBs), small secreted fungal proteins containing eight positionally conserved cysteine residues, are able to enhance the rate of enzymatic hydrolysis of PET. Species of the fungal genus Trichoderma have the most proliferated arsenal of class II hydrophobin-encoding genes among fungi. To this end, we studied two novel class II HFBs (HFB4 and HFB7) of Trichoderma. HFB4 and HFB7, produced in Escherichia coli as fusions to the C terminus of glutathione S-transferase, exhibited subtle structural differences reflected in hydrophobicity plots that correlated with unequal hydrophobicity and hydrophily, respectively, of particular amino acid residues. Both proteins exhibited a dosage-dependent stimulation effect on PET hydrolysis by cutinase from Humicola insolens, with HFB4 displaying an adsorption isotherm-like behavior, whereas HFB7 was active only at very low concentrations and was inhibitory at higher concentrations. We conclude that class II HFBs can stimulate the activity of cutinases on PET, but individual HFBs can display different properties. The present findings suggest that hydrophobins can be used in the enzymatic hydrolysis of aromatic-aliphatic polyesters such as PET.
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Isolation of a novel cutinase homolog with polyethylene terephthalate-degrading activity from leaf-branch compost by using a metagenomic approach. Appl Environ Microbiol 2011; 78:1556-62. [PMID: 22194294 DOI: 10.1128/aem.06725-11] [Citation(s) in RCA: 304] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The gene encoding a cutinase homolog, LC-cutinase, was cloned from a fosmid library of a leaf-branch compost metagenome by functional screening using tributyrin agar plates. LC-cutinase shows the highest amino acid sequence identity of 59.7% to Thermomonospora curvata lipase. It also shows the 57.4% identity to Thermobifida fusca cutinase. When LC-cutinase without a putative signal peptide was secreted to the periplasm of Escherichia coli cells with the assistance of the pelB leader sequence, more than 50% of the recombinant protein, termed LC-cutinase*, was excreted into the extracellular medium. It was purified and characterized. LC-cutinase* hydrolyzed various fatty acid monoesters with acyl chain lengths of 2 to 18, with a preference for short-chain substrates (C(4) substrate at most) most optimally at pH 8.5 and 50°C, but could not hydrolyze olive oil. It lost activity with half-lives of 40 min at 70°C and 7 min at 80°C. LC-cutinase* had an ability to degrade poly(ε-caprolactone) and polyethylene terephthalate (PET). The specific PET-degrading activity of LC-cutinase* was determined to be 12 mg/h/mg of enzyme (2.7 mg/h/μkat of pNP-butyrate-degrading activity) at pH 8.0 and 50°C. This activity is higher than those of the bacterial and fungal cutinases reported thus far, suggesting that LC-cutinase* not only serves as a good model for understanding the molecular mechanism of PET-degrading enzyme but also is potentially applicable for surface modification and degradation of PET.
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