1
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Li Y, Wang X, Zhou NY, Ding J. Yeast surface display technology: Mechanisms, applications, and perspectives. Biotechnol Adv 2024; 76:108422. [PMID: 39117125 DOI: 10.1016/j.biotechadv.2024.108422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2024] [Revised: 06/03/2024] [Accepted: 08/04/2024] [Indexed: 08/10/2024]
Abstract
Microbial cell surface display technology, which relies on genetically fusing heterologous target proteins to the cell wall through fusion with cell wall anchor proteins, has emerged as a promising and powerful method with diverse applications in biotechnology and biomedicine. Compared to classical intracellular or extracellular expression (secretion) systems, the cell surface display strategy stands out by eliminating the necessity for enzyme purification, overcoming substrate transport limitations, and demonstrating enhanced activity, stability, and selectivity. Unlike phage or bacterial surface display, the yeast surface display (YSD) system offers distinct advantages, including its large cell size, ease of culture and genetic manipulation, the use of generally regarded as safe (GRAS) host cell, the ability to ensure correct folding of complex eukaryotic proteins, and the potential for post-translational modifications. To date, YSD systems have found widespread applications in protein engineering, waste biorefineries, bioremediation, and the production of biocatalysts and biosensors. This review focuses on detailing various strategies and mechanisms for constructing YSD systems, providing a comprehensive overview of both fundamental principles and practical applications. Finally, the review outlines future perspectives for developing novel forms of YSD systems and explores potential applications in diverse fields.
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Affiliation(s)
- Yibo Li
- Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming 650500, China; Key Laboratory of Yunnan for Biomass Energy and Biotechnology of Environment, Yunnan Normal University, Kunming 650500, China
| | - Xu Wang
- Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming 650500, China; Key Laboratory of Yunnan for Biomass Energy and Biotechnology of Environment, Yunnan Normal University, Kunming 650500, China
| | - Ning-Yi Zhou
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic and Developmental Sciences, and School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Junmei Ding
- Engineering Research Center of Sustainable Development and Utilization of Biomass Energy, Ministry of Education, Yunnan Normal University, Kunming 650500, China; Key Laboratory of Yunnan for Biomass Energy and Biotechnology of Environment, Yunnan Normal University, Kunming 650500, China.
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2
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Chen Y, Mao L, Wang W, Yuan H, Yang C, Zhang R, Zhou Y, Zhang G. An efficient strategy to tailor PET hydrolase: Simple preparation with high yield and enhanced hydrolysis to micro-nano plastics. Int J Biol Macromol 2024:136479. [PMID: 39393729 DOI: 10.1016/j.ijbiomac.2024.136479] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2024] [Revised: 09/15/2024] [Accepted: 10/08/2024] [Indexed: 10/13/2024]
Abstract
Polyethylene terephthalate (PET) nano/microplastics (PET-NMPs) are regarded as an emergent hazardous waste for the environment. Enzymatic treatment of PET-NMPs is one of the most promising methods. However, strategies for mining or engineering of PET hydrolases with better characteristics and the simple and cost-effective preparation of them are the bottlenecks currently. Herein, we proposed a gene fusion strategy to tailor PET hydrolase (ICCG) with ferritin (namely FC) towards micro-nano PET degradation. The purified FC was obtained by an easy scalable low-speed centrifugation with 80.8 % activity recovery and 82.9 % protein recovery compared to the crude protein extraction, with the final high yield of 2.17 g/L. Encouragingly, unlike only hydrolyzing amorphous PET (crystallinity lower than 10 %), the resulted FC showed 84.53 mgTPA/h/mgEnzyme specific activity at 70 °C for 5 h towards micro-PET with relatively high crystallinity (20.54 %) at the optimized enzyme/PET ratio of 1:100 (Wt), without producing intermediates. The supreme activity of FC was closely related to its enhanced affinity towards substrate, increased substrate's ester bond tensions and binding pocket volume. More interestingly, FC exhibited promising stability not only in storage or high temperature, but also in simulated seawater (hypersaline environment), with the half-lives of 128.4 days at 30 °C. Thus, the all-in-one strategy will offer a green and alternative solution to assist the PET-NMPs waste treatments such as recycling in the high-temperature reactor or degradation in seawater.
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Affiliation(s)
- Yaxin Chen
- College of Chemical Engineering, Huaqiao University, Xiamen 361021, Fujian Province, PR China
| | - Lei Mao
- College of Chemical Engineering, Huaqiao University, Xiamen 361021, Fujian Province, PR China
| | - Weijuan Wang
- College of Chemical Engineering, Huaqiao University, Xiamen 361021, Fujian Province, PR China
| | - Hang Yuan
- College of Chemical Engineering, Huaqiao University, Xiamen 361021, Fujian Province, PR China
| | - Chun Yang
- College of Chemical Engineering, Huaqiao University, Xiamen 361021, Fujian Province, PR China
| | - Ruifang Zhang
- College of Chemical Engineering, Huaqiao University, Xiamen 361021, Fujian Province, PR China
| | - Yanhong Zhou
- College of Chemical Engineering, Huaqiao University, Xiamen 361021, Fujian Province, PR China
| | - Guangya Zhang
- College of Chemical Engineering, Huaqiao University, Xiamen 361021, Fujian Province, PR China.
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3
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Yip A, McArthur OD, Ho KC, Aucoin MG, Ingalls BP. Degradation of polyethylene terephthalate (PET) plastics by wastewater bacteria engineered via conjugation. Microb Biotechnol 2024; 17:e70015. [PMID: 39315602 PMCID: PMC11420662 DOI: 10.1111/1751-7915.70015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2024] [Accepted: 08/22/2024] [Indexed: 09/25/2024] Open
Abstract
Wastewater treatment plants are one of the major pathways for microplastics to enter the environment. In general, microplastics are contaminants of global concern that pose risks to ecosystems and human health. Here, we present a proof-of-concept for reduction of microplastic pollution emitted from wastewater treatment plants: delivery of recombinant DNA to bacteria in wastewater to enable degradation of polyethylene terephthalate (PET). Using a broad-host-range conjugative plasmid, we enabled various bacterial species from a municipal wastewater sample to express FAST-PETase, which was released into the extracellular environment. We found that FAST-PETase purified from some transconjugant isolates could degrade about 40% of a 0.25 mm thick commercial PET film within 4 days at 50°C. We then demonstrated partial degradation of a post-consumer PET product over 5-7 days by exposure to conditioned media from isolates. These results have broad implications for addressing the global plastic pollution problem by enabling environmental bacteria to degrade PET.
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Affiliation(s)
- Aaron Yip
- Department of Chemical Engineering, University of Waterloo, Waterloo, Ontario, Canada
| | - Owen D McArthur
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
| | - Kalista C Ho
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
| | - Marc G Aucoin
- Department of Chemical Engineering, University of Waterloo, Waterloo, Ontario, Canada
| | - Brian P Ingalls
- Department of Applied Mathematics, University of Waterloo, Waterloo, Ontario, Canada
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4
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dos Santos A, da Costa CHS, Silva PHA, Skaf MS, Lameira J. Exploring the Reaction Mechanism of Polyethylene Terephthalate Biodegradation through QM/MM Approach. J Phys Chem B 2024; 128:7486-7499. [PMID: 39072475 PMCID: PMC11317977 DOI: 10.1021/acs.jpcb.4c02207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Revised: 07/06/2024] [Accepted: 07/16/2024] [Indexed: 07/30/2024]
Abstract
The enzyme PETase fromIdeonella sakaiensis (IsPETase) strain 201-F6 can catalyze the hydrolysis of polyethylene terephthalate (PET), mainly converting it into mono(2-hydroxyethyl) terephthalic acid (MHET). In this study, we used quantum mechanics/molecular mechanics (QM/MM) simulations to explore the molecular details of the catalytic reaction mechanism of IsPETase in the formation of MHET. The QM region was described with AM1d/PhoT and M06-2X/6-31+G(d,p) potential. QM/MM simulations unveil the complete enzymatic PET hydrolysis mechanism and identify two possible reaction pathways for acylation and deacylation steps. The barrier obtained at M06-2X/6-31+G(d,p)/MM potential for the deacylation step corresponds to 20.4 kcal/mol, aligning with the experimental value of 18 kcal/mol. Our findings indicate that deacylation is the rate-limiting step of the process. Furthermore, per-residue interaction energy contributions revealed unfavorable contributions to the transition state of amino acids located at positions 200-230, suggesting potential sites for targeted mutations. These results can contribute to the development of more active and selective enzymes for PET depolymerization.
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Affiliation(s)
- Alberto
M. dos Santos
- Institute
of Chemistry and Centre for Computer in Engineering and Sciences, University of Campinas (UNICAMP), Campinas 13084-862, Sao Paulo, Brazil
| | - Clauber H. S. da Costa
- Institute
of Chemistry and Centre for Computer in Engineering and Sciences, University of Campinas (UNICAMP), Campinas 13084-862, Sao Paulo, Brazil
| | - Pedro H. A. Silva
- Institute
of Biological Sciences, Federal University
of Para, 66075-110 Belem, Para, Brazil
| | - Munir S. Skaf
- Institute
of Chemistry and Centre for Computer in Engineering and Sciences, University of Campinas (UNICAMP), Campinas 13084-862, Sao Paulo, Brazil
| | - Jerônimo Lameira
- Institute
of Biological Sciences, Federal University
of Para, 66075-110 Belem, Para, Brazil
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5
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Mubayi V, Ahern CB, Calusinska M, O’Malley MA. Toward a Circular Bioeconomy: Designing Microbes and Polymers for Biodegradation. ACS Synth Biol 2024; 13:1978-1993. [PMID: 38918080 PMCID: PMC11264326 DOI: 10.1021/acssynbio.4c00077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 06/11/2024] [Accepted: 06/12/2024] [Indexed: 06/27/2024]
Abstract
Polymer production is rapidly increasing, but there are no large-scale technologies available to effectively mitigate the massive accumulation of these recalcitrant materials. One potential solution is the development of a carbon-neutral polymer life cycle, where microorganisms convert plant biomass to chemicals, which are used to synthesize biodegradable materials that ultimately contribute to the growth of new plants. Realizing a circular carbon life cycle requires the integration of knowledge across microbiology, bioengineering, materials science, and organic chemistry, which itself has hindered large-scale industrial advances. This review addresses the biodegradation status of common synthetic polymers, identifying novel microbes and enzymes capable of metabolizing these recalcitrant materials and engineering approaches to enhance their biodegradation pathways. Design considerations for the next generation of biodegradable polymers are also reviewed, and finally, opportunities to apply findings from lignocellulosic biodegradation to the design and biodegradation of similarly recalcitrant synthetic polymers are discussed.
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Affiliation(s)
- Vikram Mubayi
- Department
of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
| | - Colleen B. Ahern
- Department
of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
| | - Magdalena Calusinska
- Department
of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
- Environmental
Research and Innovation Department, Luxembourg
Institute of Science and Technology, L-4422 Belvaux, Luxembourg
| | - Michelle A. O’Malley
- Department
of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
- Department
of Bioengineering, University of California, Santa Barbara, California 93106, United States
- Joint
BioEnergy Institute (JBEI), Emeryville, California 94608, United States
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6
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Schneier A, Melaugh G, Sadler JC. Engineered plastic-associated bacteria for biodegradation and bioremediation. BIOTECHNOLOGY FOR THE ENVIRONMENT 2024; 1:7. [PMID: 39026535 PMCID: PMC11256910 DOI: 10.1186/s44314-024-00007-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Accepted: 04/29/2024] [Indexed: 07/20/2024]
Abstract
The global plastic waste crisis has triggered the development of novel methods for removal of recalcitrant polymers from the environment. Biotechnological approaches have received particular attention due to their potential for enabling sustainable, low-intensity bioprocesses which could also be interfaced with microbial upcycling pathways to support the emerging circular bioeconomy. However, low biodegradation efficiency of solid plastic materials remains a bottleneck, especially at mesophilic conditions required for one-pot degradation and upcycling. A promising strategy used in nature to address this is localisation of plastic-degrading microbes to the plastic surface via biofilm-mediated surface association. This review highlights progress and opportunities in leveraging these naturally occurring mechanisms of biofilm formation and other cell-surface adhesion biotechnologies to co-localise engineered cells to plastic surfaces. We further discuss examples of combining these approaches with extracellular expression of plastic-degrading enzymes to accelerate plastic degradation. Additionally, we review this topic in the context of nano- and microplastics bioremediation and their removal from wastewater and finally propose future research directions for this nascent field.
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Affiliation(s)
- Arianna Schneier
- Institute of Quantitative Biology, Biochemistry and Biotechnology, School of Biological Sciences, University of Edinburgh, Roger Land Building, Alexander Crum Brown Road, King’s Buildings, Edinburgh, EH9 3FF UK
| | - Gavin Melaugh
- School of Physics and Astronomy, University of Edinburgh, Edinburgh, EH9 3FD UK
- School of Engineering, University of Edinburgh, Edinburgh, EH9 3JL UK
| | - Joanna C. Sadler
- Institute of Quantitative Biology, Biochemistry and Biotechnology, School of Biological Sciences, University of Edinburgh, Roger Land Building, Alexander Crum Brown Road, King’s Buildings, Edinburgh, EH9 3FF UK
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7
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Wang C, Long R, Lin X, Liu W, Zhu L, Jiang L. Development and characterization of a bacterial enzyme cascade reaction system for efficient and stable PET degradation. JOURNAL OF HAZARDOUS MATERIALS 2024; 472:134480. [PMID: 38703683 DOI: 10.1016/j.jhazmat.2024.134480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 04/15/2024] [Accepted: 04/27/2024] [Indexed: 05/06/2024]
Abstract
The widespread use of polyethylene terephthalate (PET) in various industries has led to a surge in microplastics (MPs) pollution, posing a significant threat to ecosystems and human health. To address this, we have developed a bacterial enzyme cascade reaction system (BECRS) that focuses on the efficient degradation of PET. This system harnesses the Escherichia coli (E. coli) surface to display CsgA protein, which forms curli fibers, along with the carbohydrate-binding module 3 (CBM3) and PETases, to enhance the adsorption and degradation of PET. The study demonstrated that the BECRS achieved a notable PET film degradation rate of 3437 ± 148 μg/(d*cm²), with a degradation efficiency of 21.40% for crystalline PET MPs, and the degradation products were all converted to TPA. The stability of the system was evidenced by retaining over 80% of its original activity after multiple uses and during one month of storage. Molecular dynamics simulations confirmed that the presence of CsgA did not interfere with the enzymatic activity of PETases. This BECRS represents a significant step forward in the biodegradation of PET, particularly microplastics, offering a practical and sustainable solution for environmental pollution control.
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Affiliation(s)
- Chengyong Wang
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, China; College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, China
| | - Rui Long
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, China
| | - Xiran Lin
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, Nanjing 211816, China
| | - Wei Liu
- College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, China
| | - Liying Zhu
- College of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, China
| | - Ling Jiang
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, Nanjing 211816, China; College of Food Science and Light Industry, Nanjing Tech University, Nanjing 211816, China.
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8
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Amanna R, Rakshit SK. Review of nomenclature and methods of analysis of polyethylene terephthalic acid hydrolyzing enzymes activity. Biodegradation 2024; 35:341-360. [PMID: 37688750 DOI: 10.1007/s10532-023-10048-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 08/15/2023] [Indexed: 09/11/2023]
Abstract
Enzymatic degradation of polyethylene terephthalic acid (PET) has been gaining increasing importance. This has resulted in a significant increase in the search for newer enzymes and the development of more efficient enzyme-based systems. Due to the lack of a standard screening process, screening new enzymes has relied on other assays to determine the presence of esterase activity. This, in turn, has led to various nomenclatures and methods used to describe them and measure their activity. Since all PET-hydrolyzing enzymes are α/β hydrolases, they catalyze a serine nucleophilic attack and cleave an ester bond. They are lipases, esterases, cutinases and hydrolases. This has been used interchangeably, leading to difficulties while comparing results and evaluating progress. This review discusses the varied enzyme nomenclature being adapted, the different assays and analysis methods reported, and the strategies used to increase PET-hydrolyzing enzyme efficiency. A section on the various ways to quantify PET hydrolysis is also covered.
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Affiliation(s)
- Ruth Amanna
- Department of Biotechnology, Lakehead University, Thunder Bay, ON, Canada
- Biorefining Research Institute (BRI), Lakehead University, Thunder Bay, ON, Canada
| | - Sudip K Rakshit
- Department of Biotechnology, Lakehead University, Thunder Bay, ON, Canada.
- Biorefining Research Institute (BRI), Lakehead University, Thunder Bay, ON, Canada.
- Department of Chemical Engineering, Lakehead University, Thunder Bay, ON, Canada.
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9
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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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10
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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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11
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Han W, Zhang J, Chen Q, Xie Y, Zhang M, Qu J, Tan Y, Diao Y, Wang Y, Zhang Y. Biodegradation of poly(ethylene terephthalate) through PETase surface-display: From function to structure. JOURNAL OF HAZARDOUS MATERIALS 2024; 461:132632. [PMID: 37804764 DOI: 10.1016/j.jhazmat.2023.132632] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 09/20/2023] [Accepted: 09/24/2023] [Indexed: 10/09/2023]
Abstract
Polyethylene terephthalate (PET) is one of the most used plastics which has caused some environmental pollution and social problems. Although many newly discovered or modified PET hydrolases have been reported at present, there is still a lack of comparison between their hydrolytic capacities, as well as the need for new biotechnology to apply them for the PET treatment. Here, we systematically studied the surface-display technology for PET hydrolysis using several PET hydrolases. It is found that anchoring protein types had little influence on the surface-display result under T7 promoter, while the PET hydrolase types were more important. By contrast, the newly reported FAST-PETase showed the strongest hydrolysis effect, achieving 71.3% PET hydrolysis in 24 h by pGSA-FAST-PETase. Via model calculation, FAST-PETase indeed exhibited higher temperature tolerance and catalytic capacity. Besides, smaller particle size and lower crystallinity favored the hydrolysis of PET pellets. Through protein structure comparison, we summarized the common characteristics of efficient PET-hydrolyzing enzymes and proposed three main crystal structures of PET enzymes via crystal structural analysis, with ISPETase being the representative and main structure. Surface co-display of FAST-PETase and MHETase can promote the hydrolysis of PET, and the C-terminal of the fusion protein is crucial for PET hydrolysis. The results of our research can be helpful for PET contamination removal as well as other areas involving the application of enzymes. SYNOPSIS: This research can promote the development of better PET hydrolase and its applications in PET pollution treatment via bacteria surface-display.
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Affiliation(s)
- Wei Han
- School of Resources and Environment, Northeast Agricultural University, Heilongjiang 150030, PR China
| | - Jun Zhang
- School of Resources and Environment, Northeast Agricultural University, Heilongjiang 150030, PR China
| | - Qi Chen
- School of Resources and Environment, Northeast Agricultural University, Heilongjiang 150030, PR China
| | - Yuzhu Xie
- School of Resources and Environment, Northeast Agricultural University, Heilongjiang 150030, PR China
| | - Meng Zhang
- School of Resources and Environment, Northeast Agricultural University, Heilongjiang 150030, PR China
| | - Jianhua Qu
- School of Resources and Environment, Northeast Agricultural University, Heilongjiang 150030, PR China
| | - Yuanji Tan
- School of Resources and Environment, Northeast Agricultural University, Heilongjiang 150030, PR China
| | - Yiran Diao
- School of Resources and Environment, Northeast Agricultural University, Heilongjiang 150030, PR China
| | - Yixuan Wang
- School of Resources and Environment, Northeast Agricultural University, Heilongjiang 150030, PR China
| | - Ying Zhang
- School of Resources and Environment, Northeast Agricultural University, Heilongjiang 150030, PR China.
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12
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Qiu J, Chen Y, Zhang L, Wu J, Zeng X, Shi X, Liu L, Chen J. A comprehensive review on enzymatic biodegradation of polyethylene terephthalate. ENVIRONMENTAL RESEARCH 2024; 240:117427. [PMID: 37865324 DOI: 10.1016/j.envres.2023.117427] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 10/11/2023] [Accepted: 10/15/2023] [Indexed: 10/23/2023]
Abstract
Polyethylene terephthalate (PET) is a polymer synthesized via the dehydration and condensation reaction between ethylene glycol and terephthalic acid. PET has emerged as one of the most extensively employed plastic materials due to its exceptional plasticity and durability. Nevertheless, PET has a complex structure and is extremely difficult to degrade in nature, causing severe pollution to the global ecological environment and posing a threat to human health. Currently, the methods for PET processing mainly include physical, chemical, and biological methods. Biological enzyme degradation is considered the most promising PET degradation method. In recent years, an increasing number of enzymes that can degrade PET have been identified, and they primarily target the ester bond of PET. This review comprehensively introduced the latest research progress in PET enzymatic degradation from the aspects of PET-degrading enzymes, PET biodegradation pathways, the catalytic mechanism of PET-degrading enzymes, and biotechnological strategies for enhancing PET-degrading enzymes. On this basis, the current challenges within the enzymatic PET degradation process were summarized, and the directions that need to be worked on in the future were pointed out. This review provides a reference and basis for the subsequent effective research on PET biodegradation.
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Affiliation(s)
- Jiarong Qiu
- School of Advanced Manufacturing, Fuzhou University, Jinjiang 362251, China; Development Center of Science and Education Park of Fuzhou University, Jinjiang, 362251, China
| | - Yuxin Chen
- School of Advanced Manufacturing, Fuzhou University, Jinjiang 362251, China
| | - Liangqing Zhang
- School of Advanced Manufacturing, Fuzhou University, Jinjiang 362251, China; Development Center of Science and Education Park of Fuzhou University, Jinjiang, 362251, China.
| | - Jinzhi Wu
- School of Advanced Manufacturing, Fuzhou University, Jinjiang 362251, China
| | - Xianhai Zeng
- College of Energy, Xiamen University, Xiamen 361102, China
| | - Xinguo Shi
- School of Advanced Manufacturing, Fuzhou University, Jinjiang 362251, China
| | - Lemian Liu
- School of Advanced Manufacturing, Fuzhou University, Jinjiang 362251, China
| | - Jianfeng Chen
- School of Advanced Manufacturing, Fuzhou University, Jinjiang 362251, China
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13
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Aer L, Qin H, Wo P, Feng J, Tang L. Signal peptide independent secretion of bifunctional dual-hydrolase to enhance the bio-depolymerization of polyethylene terephthalate. BIORESOURCE TECHNOLOGY 2024; 391:129884. [PMID: 37852506 DOI: 10.1016/j.biortech.2023.129884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 10/16/2023] [Accepted: 10/16/2023] [Indexed: 10/20/2023]
Abstract
The use of polyethylene terephthalate (PET) results in a significant amount of plastic waste, which poses a threat to the environment and human health. Dual-enzyme system is promising candidate for PET depolymerization. However, its production in Escherichia coli is challenging, especially for secretory expression. Herein, a novel bifunctional dual-enzyme, TfH-FPE, was constructed through fusion of FAST-PETase and TfH. TfH modifies cell membrane permeability via phospholipid degradation, thus facilitating the secretion of TfH-FPE into the medium. After systematic optimization, purified secreted TfH-FPE reached 104 ± 5.2 mg/L, which is 32.5-fold higher than that of the secreted enzyme using a signal peptide. TfH-FPE exhibits remarkable PET depolymerization capacity compared to FAST-PETase, releasing 6-fold more product than FAST-PETase and 2-fold more product than an equimolar enzyme mixture. Collectively, this study explores a novel secretory approach for efficient production of TfH-FPE and provides a valuable tool to promote PET bio-depolymerization via multi-enzyme cascades.
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Affiliation(s)
- Lizhu Aer
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Huiling Qin
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Peng Wo
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Juan Feng
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054, China; Center for Informational Biology, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Lixia Tang
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054, China; Center for Informational Biology, University of Electronic Science and Technology of China, Chengdu 610054, China.
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14
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Cribari MA, Unger MJ, Unarta IC, Ogorek AN, Huang X, Martell JD. Ultrahigh-Throughput Directed Evolution of Polymer-Degrading Enzymes Using Yeast Display. J Am Chem Soc 2023; 145:27380-27389. [PMID: 38051911 PMCID: PMC11058326 DOI: 10.1021/jacs.3c08291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2023]
Abstract
Enzymes that degrade synthetic polymers have attracted intense interest for eco-friendly plastic recycling. However, because enzymes did not evolve for the cleavage of abiotic polymers, directed evolution strategies are needed to enhance activity for plastic degradation. Previous directed evolution efforts relied on polymer degradation assays that were limited to screening ∼104 mutants. Here, we report a high-throughput yeast surface display platform to rapidly evaluate >107 enzyme mutants for increased activity in cleaving synthetic polymers. In this platform, individual yeast cells display distinct mutants, and enzyme activity is detected by a change in fluorescence upon the cleavage of a synthetic probe resembling a polymer of interest. Highly active mutants are isolated by fluorescence activated cell sorting and identified through DNA sequencing. To demonstrate this platform, we performed directed evolution of a polyethylene terephthalate (PET)-depolymerizing enzyme, leaf and branch compost cutinase (LCC). We identified activity-boosting mutations that substantially increased the kinetics of degradation of solid PET films. Biochemical assays and molecular dynamics (MD) simulations of the most active variants suggest that the H218Y mutation improves the binding of the enzyme to PET. Overall, this evolution platform increases the screening throughput of polymer-degrading enzymes by 3 orders of magnitude and identifies mutations that enhance kinetics for depolymerizing solid substrates.
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Affiliation(s)
- Mario A. Cribari
- Department of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | - Maxwell J. Unger
- Department of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | - Ilona C. Unarta
- Department of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
- Theoretical Chemistry Institute, Department of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | - Ashley N. Ogorek
- Department of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | - Xuhui Huang
- Department of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
- Theoretical Chemistry Institute, Department of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
| | - Jeffrey D. Martell
- Department of Chemistry, University of Wisconsin−Madison, Madison, Wisconsin 53706, United States
- Carbone Cancer Center, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53705, United States
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15
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Hu F, Wang P, Li Y, Ling J, Ruan Y, Yu J, Zhang L. Bioremediation of environmental organic pollutants by Pseudomonas aeruginosa: Mechanisms, methods and challenges. ENVIRONMENTAL RESEARCH 2023; 239:117211. [PMID: 37778604 DOI: 10.1016/j.envres.2023.117211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2023] [Revised: 09/10/2023] [Accepted: 09/25/2023] [Indexed: 10/03/2023]
Abstract
The development of the chemical industry has led to a boom in daily consumption and convenience, but has also led to the release of large amounts of organic pollutants, such as petroleum hydrocarbons, plastics, pesticides, and dyes. These pollutants are often recalcitrant to degradation in the environment, whereby the most problematic compounds may even lead to carcinogenesis, teratogenesis and mutagenesis in animals and humans after accumulation in the food chain. Microbial degradation of organic pollutants is efficient and environmentally friendly, which is why it is considered an ideal method. Numerous studies have shown that Pseudomonas aeruginosa is a powerful platform for the remediation of environmental pollution with organic chemicals due to its diverse metabolic networks and its ability to secrete biosurfactants to make hydrophobic substrates more bioavailable, thereby facilitating degradation. In this paper, the mechanisms and methods of the bioremediation of environmental organic pollutants (EOPs) by P. aeruginosa are reviewed. The challenges of current studies are highlighted, and new strategies for future research are prospected. Metabolic pathways and critical enzymes must be further deciphered, which is significant for the construction of a bioremediation platform based on this powerful organism.
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Affiliation(s)
- Fanghui Hu
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Jiangsu, Nanjing, 210023, China
| | - Panlin Wang
- School of Bioengineering, East China University of Science and Technology, Shanghai, 200237, China
| | - Yunhan Li
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Jiangsu, Nanjing, 210023, China
| | - Jiahuan Ling
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Jiangsu, Nanjing, 210023, China
| | - Yongqiang Ruan
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Jiangsu, Nanjing, 210023, China
| | - Jiaojiao Yu
- School of Medical Imaging, Tianjin Medical University, Tianjin, 300203, China.
| | - Lihui Zhang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Jiangsu, Nanjing, 210023, China.
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16
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Hu J, Chen Y. Constructing Escherichia coli co-display systems for biodegradation of polyethylene terephthalate. BIORESOUR BIOPROCESS 2023; 10:91. [PMID: 38647917 PMCID: PMC10992762 DOI: 10.1186/s40643-023-00711-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 11/25/2023] [Indexed: 04/25/2024] Open
Abstract
BACKGROUND The accumulation of fast-growing polyethylene terephthalate (PET) wastes has posed numerous threats to the environments and human health. Enzymatic degradation of PET is a promising approach for PET waste treatment. Currently, the efficiency of various PET biodegradation systems requires further improvements. RESULTS In this work, we engineered whole cell systems with co-display of strong adhesive proteins and the most active PETase for PET biodegradation in E. coli cells. Adhesive proteins of cp52k and mfp-3 and Fast-PETase were simultaneously displayed on the surfaces of E. coli cells, and the resulting cells displaying mfp-3 showed 50% increase of adhesion ability compared to those without adhesive proteins. Consequently, the degradation rate of E. coli cells co-displaying mfp-3 and Fast-PETase for amorphous PET exceeded 15% within 24 h, exhibiting fast and thorough PET degradation. CONCLUSIONS Through the engineering of co-display systems in E. coli cells, PET degradation efficiency was significantly increased compared to E. coli cells with sole display of Fast-PETase and free enzyme. This feasible E. coli co-display system could be served as a convenient tool for extending the treatment options for PET biodegradation.
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Affiliation(s)
- Jiayu Hu
- Laboratory of Chemical Biology, School of Life Science and Technology, China Pharmaceutical University, Nanjing, 211198, Jiangsu, People's Republic of China
| | - Yijun Chen
- Laboratory of Chemical Biology, School of Life Science and Technology, China Pharmaceutical University, Nanjing, 211198, Jiangsu, People's Republic of China.
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17
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Choi SY, Lee Y, Yu HE, Cho IJ, Kang M, Lee SY. Sustainable production and degradation of plastics using microbes. Nat Microbiol 2023; 8:2253-2276. [PMID: 38030909 DOI: 10.1038/s41564-023-01529-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 10/16/2023] [Indexed: 12/01/2023]
Abstract
Plastics are indispensable in everyday life and industry, but the environmental impact of plastic waste on ecosystems and human health is a huge concern. Microbial biotechnology offers sustainable routes to plastic production and waste management. Bacteria and fungi can produce plastics, as well as their constituent monomers, from renewable biomass, such as crops, agricultural residues, wood and organic waste. Bacteria and fungi can also degrade plastics. We review state-of-the-art microbial technologies for sustainable production and degradation of bio-based plastics and highlight the potential contributions of microorganisms to a circular economy for plastics.
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Affiliation(s)
- So Young Choi
- Metabolic and Biomolecular Engineering National Research Laboratory, Systems Metabolic Engineering and Systems Healthcare Cross-Generation Collaborative Laboratory, Department of Chemical and Biomolecular Engineering (BK21 Four), Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
- KAIST Institute for BioCentury, KAIST, Daejeon, Republic of Korea
- BioProcess Engineering Research Center, KAIST, Daejeon, Republic of Korea
| | - Youngjoon Lee
- Metabolic and Biomolecular Engineering National Research Laboratory, Systems Metabolic Engineering and Systems Healthcare Cross-Generation Collaborative Laboratory, Department of Chemical and Biomolecular Engineering (BK21 Four), Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
- KAIST Institute for BioCentury, KAIST, Daejeon, Republic of Korea
- BioProcess Engineering Research Center, KAIST, Daejeon, Republic of Korea
| | - Hye Eun Yu
- Metabolic and Biomolecular Engineering National Research Laboratory, Systems Metabolic Engineering and Systems Healthcare Cross-Generation Collaborative Laboratory, Department of Chemical and Biomolecular Engineering (BK21 Four), Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
- KAIST Institute for BioCentury, KAIST, Daejeon, Republic of Korea
| | - In Jin Cho
- Metabolic and Biomolecular Engineering National Research Laboratory, Systems Metabolic Engineering and Systems Healthcare Cross-Generation Collaborative Laboratory, Department of Chemical and Biomolecular Engineering (BK21 Four), Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
- KAIST Institute for BioCentury, KAIST, Daejeon, Republic of Korea
- BioProcess Engineering Research Center, KAIST, Daejeon, Republic of Korea
| | - Minju Kang
- Metabolic and Biomolecular Engineering National Research Laboratory, Systems Metabolic Engineering and Systems Healthcare Cross-Generation Collaborative Laboratory, Department of Chemical and Biomolecular Engineering (BK21 Four), Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
- KAIST Institute for BioCentury, KAIST, Daejeon, Republic of Korea
| | - Sang Yup Lee
- Metabolic and Biomolecular Engineering National Research Laboratory, Systems Metabolic Engineering and Systems Healthcare Cross-Generation Collaborative Laboratory, Department of Chemical and Biomolecular Engineering (BK21 Four), Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea.
- KAIST Institute for BioCentury, KAIST, Daejeon, Republic of Korea.
- BioProcess Engineering Research Center, KAIST, Daejeon, Republic of Korea.
- BioInformatics Research Center, KAIST, Daejeon, Republic of Korea.
- Graduate School of Engineering Biology, KAIST, Daejeon, Republic of Korea.
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18
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Dhaka V, Singh S, Ramamurthy PC, Samuel J, Swamy Sunil Kumar Naik T, Khasnabis S, Prasad R, Singh J. Biological degradation of polyethylene terephthalate by rhizobacteria. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:116488-116497. [PMID: 35460002 DOI: 10.1007/s11356-022-20324-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Accepted: 04/14/2022] [Indexed: 06/14/2023]
Abstract
In view of the growing demand for plastic products, an enormous proportion of plastic waste causing the biological issue is produced. Plants in collaboration with their rhizobacteria partners are also exposed to these contaminants. The study aims to determine the rhizobacterial ability to biodegrade PET plastic. We isolated the rhizobacteria capable of degrading the PET plastic in minimal salt media using it as a sole carbon source. The three rhizospheric isolates, namely Priestia aryabhattai VT 3.12 (GenBank accession No. OK135732.1), Bacillus pseudomycoides VT 3.15 (GenBank accession No. OK135733.1), and Bacillus pumilus VT 3.16 (GenBank accession No. OK1357324.1), showed the highest degradation percentage for PET sheet and powder. The biodegradation end products post 28 days for PET sheet and 18 days of PET powder were studied by Fourier transform infrared spectroscopy (FTIR), high-performance liquid chromatography (HPLC), and scanning electron microscopy (SEM). Our results showed significant biodegradation of PET plastic, and the rate of degradation could account for over 65%. The present study proves soil rhizobacteria's potential and capabilities for efficient degradation of PET plastic occurring at the waste sites. It also implies that rhizobacteria could be beneficial in the remediation of PET waste in future applications.
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Affiliation(s)
- Vaishali Dhaka
- Department of Microbiology, Lovely Professional University, Phagwara, 144411, Punjab, India
| | - Simranjeet Singh
- Interdisciplinary Centre for Water Research (ICWaR), Indian Institute of Science, 56001, Bangalore, India
| | - Praveen C Ramamurthy
- Interdisciplinary Centre for Water Research (ICWaR), Indian Institute of Science, 56001, Bangalore, India
| | - Jastin Samuel
- Department of Microbiology, Lovely Professional University, Phagwara, 144411, Punjab, India
- Waste Valorization Research Lab, Lovely Professional University, Phagwara, 144411, Punjab, India
| | | | - Sutripto Khasnabis
- Department of Materials Engineering, Indian Institute of Science, Bangalore, 560012, India
| | - Ram Prasad
- Department of Botany, Mahatma Gandhi Central University, Motihari, 845401, Bihar, India
| | - Joginder Singh
- Department of Microbiology, Lovely Professional University, Phagwara, 144411, Punjab, India.
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19
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Duan S, Zhang N, Chao T, Wu Y, Wang M. The structural and molecular mechanisms of type II PETases: a mini review. Biotechnol Lett 2023; 45:1249-1263. [PMID: 37535135 DOI: 10.1007/s10529-023-03418-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 07/15/2023] [Indexed: 08/04/2023]
Abstract
The advent of plastics has led to significant advances for humans, although the accompanying pollution has also been a source of concern for countries globally. Consequently, a biological method to effectively degrade polyethylene terephthalate (PET) has been an area of significant scientific interest. Following the report of the highly efficient PET hydrolase from the bacterium Ideonella sakaiensis strain 201-F6 (i.e., IsPETase) in 2016, its structure has been extensively studied, showing that it belongs to the type II PETase group. Unlike type I PETases that include most known cutinases, structural investigations of type II PETases have only been conducted since 2017. Type II PETases are further divided into type IIa and IIb enzymes. Moreover, even less research has been conducted on type IIa plastic-degrading enzymes. Here, we present a review of recent studies of the structure and mechanism of type II PETases, using the known structure of the type IIa PETase PE-H from the marine bacterium Pseudomonas aestusnigri in addition to the type IIb enzyme IsPETase as representatives. These studies have provided new insights into the structural features of type II PETases that exhibit PET catalytic activity. In addition, recent studies investigating the rational design of IsPETases are reviewed and summarized alongside a discussion of controversies surrounding PETase investigations.
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Affiliation(s)
- Shuyan Duan
- College of Food Science and Pharmaceutical Engineering, Zaozhuang University, Zaozhuang, 277160, Shandong, China.
| | - Nan Zhang
- College of Food Science and Pharmaceutical Engineering, Zaozhuang University, Zaozhuang, 277160, Shandong, China
| | - Tianzhu Chao
- College of Food Science and Pharmaceutical Engineering, Zaozhuang University, Zaozhuang, 277160, Shandong, China
| | - Yaoyao Wu
- College of Food Science and Pharmaceutical Engineering, Zaozhuang University, Zaozhuang, 277160, Shandong, China
| | - Mengying Wang
- Department of Materials Science and Engineering, Southern University of Science and Technology, Shenzhen, 518055, Guangdong, China.
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20
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Liu F, Wang T, Yang W, Zhang Y, Gong Y, Fan X, Wang G, Lu Z, Wang J. Current advances in the structural biology and molecular engineering of PETase. Front Bioeng Biotechnol 2023; 11:1263996. [PMID: 37795175 PMCID: PMC10546322 DOI: 10.3389/fbioe.2023.1263996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 08/31/2023] [Indexed: 10/06/2023] Open
Abstract
Poly(ethylene terephthalate) (PET) is a highly useful synthetic polyester plastic that is widely used in daily life. However, the increase in postconsumer PET as plastic waste that is recalcitrant to biodegradation in landfills and the natural environment has raised worldwide concern. Currently, traditional PET recycling processes with thermomechanical or chemical methods also result in the deterioration of the mechanical properties of PET. Therefore, it is urgent to develop more efficient and green strategies to address this problem. Recently, a novel mesophilic PET-degrading enzyme (IsPETase) from Ideonella sakaiensis was found to streamline PET biodegradation at 30°C, albeit with a lower PET-degrading activity than chitinase or chitinase-like PET-degrading enzymes. Consequently, the molecular engineering of more efficient PETases is still required for further industrial applications. This review details current knowledge on IsPETase, MHETase, and IsPETase-like hydrolases, including the structures, ligand‒protein interactions, and rational protein engineering for improved PET-degrading performance. In particular, applications of the engineered catalysts are highlighted, including metabolic engineering of the cell factories, enzyme immobilization or cell surface display. The information is expected to provide novel insights for the biodegradation of complex polymers.
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Affiliation(s)
- Fei Liu
- School of Biological Science, Jining Medical University, Rizhao, China
| | - Tao Wang
- School of Biological Science, Jining Medical University, Rizhao, China
| | - Wentao Yang
- School of Biological Science, Jining Medical University, Rizhao, China
| | - Yingkang Zhang
- School of Biological Science, Jining Medical University, Rizhao, China
| | - Yuming Gong
- School of Biological Science, Jining Medical University, Rizhao, China
| | - Xinxin Fan
- School of Biological Science, Jining Medical University, Rizhao, China
| | - Guocheng Wang
- School of Biological Science, Jining Medical University, Rizhao, China
| | - Zhenhua Lu
- College of Chemical and Biological Engineering, Zhejiang University, Hangzhou, Zhejiang, China
| | - Jianmin Wang
- School of Pharmacy, Jining Medical University, Rizhao, China
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21
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Putman LI, Schaerer LG, Wu R, Kulas DG, Zolghadr A, Ong RG, Shonnard DR, Techtmann SM. Deconstructed Plastic Substrate Preferences of Microbial Populations from the Natural Environment. Microbiol Spectr 2023; 11:e0036223. [PMID: 37260392 PMCID: PMC10433879 DOI: 10.1128/spectrum.00362-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 05/09/2023] [Indexed: 06/02/2023] Open
Abstract
Over half of the world's plastic waste is landfilled, where it is estimated to take hundreds of years to degrade. Given the continued use and disposal of plastic products, it is vital that we develop fast and effective ways to utilize plastic waste. Here, we explore the potential of tandem chemical and biological processing to process various plastics quickly and effectively. Four samples of compost or sediment were used to set up enrichment cultures grown on mixtures of compounds, including disodium terephthalate and terephthalic acid (monomers of polyethylene terephthalate), compounds derived from the chemical deconstruction of polycarbonate, and pyrolysis oil derived from high-density polyethylene plastics. Established enrichment communities were also grown on individual substrates to investigate the substrate preferences of different taxa. Biomass harvested from the cultures was characterized using 16S rRNA gene amplicon sequencing and shotgun metagenomic sequencing. These data reveal low-diversity microbial communities structured by differences in culture inoculum, culture substrate source plastic type, and time. Microbial populations from the classes Alphaproteobacteria, Gammaproteobacteria, Actinobacteria, and Acidobacteriae were significantly enriched when grown on substrates derived from high-density polyethylene and polycarbonate. The metagenomic data contain abundant aromatic and aliphatic hydrocarbon degradation genes relevant to the biodegradation of deconstructed plastic substrates used here. We show that microbial populations from diverse environments are capable of growth on substrates derived from the chemical deconstruction or pyrolysis of multiple plastic types and that paired chemical and biological processing of plastics should be further developed for industrial applications to manage plastic waste. IMPORTANCE The durability and impermeable nature of plastics have made them a popular material for numerous applications, but these same qualities make plastics difficult to dispose of, resulting in massive amounts of accumulated plastic waste in landfills and the natural environment. Since plastic use and disposal are projected to increase in the future, novel methods to effectively break down and dispose of current and future plastic waste are desperately needed. We show that the products of chemical deconstruction or pyrolysis of plastic can successfully sustain the growth of low-diversity microbial communities. These communities were enriched from multiple environmental sources and are capable of degrading complex xenobiotic carbon compounds. This study demonstrates that tandem chemical and biological processing can be used to degrade multiple types of plastics over a relatively short period of time and may be a future avenue for the mitigation of rapidly accumulating plastic waste.
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Affiliation(s)
- Lindsay I. Putman
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan, USA
| | - Laura G. Schaerer
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan, USA
| | - Ruochen Wu
- Department of Chemical Engineering, Michigan Technological University, Houghton, Michigan, USA
| | - Daniel G. Kulas
- Department of Chemical Engineering, Michigan Technological University, Houghton, Michigan, USA
| | - Ali Zolghadr
- Department of Chemical Engineering, Michigan Technological University, Houghton, Michigan, USA
| | - Rebecca G. Ong
- Department of Chemical Engineering, Michigan Technological University, Houghton, Michigan, USA
| | - David R. Shonnard
- Department of Chemical Engineering, Michigan Technological University, Houghton, Michigan, USA
| | - Stephen M. Techtmann
- Department of Biological Sciences, Michigan Technological University, Houghton, Michigan, USA
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22
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Williams GB, Ma H, Khusnutdinova AN, Yakunin AF, Golyshin PN. Harnessing extremophilic carboxylesterases for applications in polyester depolymerisation and plastic waste recycling. Essays Biochem 2023; 67:715-729. [PMID: 37334661 PMCID: PMC10423841 DOI: 10.1042/ebc20220255] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Revised: 06/01/2023] [Accepted: 06/05/2023] [Indexed: 06/20/2023]
Abstract
The steady growth in industrial production of synthetic plastics and their limited recycling have resulted in severe environmental pollution and contribute to global warming and oil depletion. Currently, there is an urgent need to develop efficient plastic recycling technologies to prevent further environmental pollution and recover chemical feedstocks for polymer re-synthesis and upcycling in a circular economy. Enzymatic depolymerization of synthetic polyesters by microbial carboxylesterases provides an attractive addition to existing mechanical and chemical recycling technologies due to enzyme specificity, low energy consumption, and mild reaction conditions. Carboxylesterases constitute a diverse group of serine-dependent hydrolases catalysing the cleavage and formation of ester bonds. However, the stability and hydrolytic activity of identified natural esterases towards synthetic polyesters are usually insufficient for applications in industrial polyester recycling. This necessitates further efforts on the discovery of robust enzymes, as well as protein engineering of natural enzymes for enhanced activity and stability. In this essay, we discuss the current knowledge of microbial carboxylesterases that degrade polyesters (polyesterases) with focus on polyethylene terephthalate (PET), which is one of the five major synthetic polymers. Then, we briefly review the recent progress in the discovery and protein engineering of microbial polyesterases, as well as developing enzyme cocktails and secreted protein expression for applications in the depolymerisation of polyester blends and mixed plastics. Future research aimed at the discovery of novel polyesterases from extreme environments and protein engineering for improved performance will aid developing efficient polyester recycling technologies for the circular plastics economy.
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Affiliation(s)
- Gwion B Williams
- Centre for Environmental Biotechnology, School of Natural Sciences, Bangor University, Deiniol Road, Bangor LL57 2UW, U.K
| | - Hairong Ma
- Centre for Environmental Biotechnology, School of Natural Sciences, Bangor University, Deiniol Road, Bangor LL57 2UW, U.K
| | - Anna N Khusnutdinova
- Centre for Environmental Biotechnology, School of Natural Sciences, Bangor University, Deiniol Road, Bangor LL57 2UW, U.K
| | - Alexander F Yakunin
- Centre for Environmental Biotechnology, School of Natural Sciences, Bangor University, Deiniol Road, Bangor LL57 2UW, U.K
| | - Peter N Golyshin
- Centre for Environmental Biotechnology, School of Natural Sciences, Bangor University, Deiniol Road, Bangor LL57 2UW, U.K
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23
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Fang Y, Chao K, He J, Wang Z, Chen Z. High-efficiency depolymerization/degradation of polyethylene terephthalate plastic by a whole-cell biocatalyst. 3 Biotech 2023; 13:138. [PMID: 37124986 PMCID: PMC10130265 DOI: 10.1007/s13205-023-03557-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Accepted: 04/06/2023] [Indexed: 05/02/2023] Open
Abstract
Polyethylene terephthalate (PET) is the most abundantly produced plastic due to its excellent performance, but is also the primary source of poorly degradable plastic pollution. The development of environment-friendly PET biodegradation is attracting increasing interest. The leaf-branch compost cutinase mutant ICCG (F243I/D238C/S283C/Y127G) exhibits the best hydrolytic activity and thermostability of all known PET hydrolases. However, its superior PET degradation is highly dependent on its preparation as a purified enzyme, which critically reduces its industrial utility. Herein, we report the use of rational design and combinatorial mutagenesis to develop a novel ICCG mutant RITK (D53R/R143I/D193T/E208K) that demonstrated excellent whole-cell biocatalytic activity. Whole cells expressing RITK showed an 8.33-fold increase in biocatalytic activity compared to those expressing ICCG. Thermostability was also improved. After reacting at 85 °C for 3 h, purified RITK exhibited a 12.75-fold increase in depolymerization compared to ICCG. These results will greatly enhance the industrial utility of PET hydrolytic enzymes and further the progress of PET recycling. Supplementary Information The online version contains supplementary material available at 10.1007/s13205-023-03557-4.
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Affiliation(s)
- Yaxuan Fang
- Laboratory of Biocatalysis, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 311121 Zhejiang China
| | - Kexin Chao
- Laboratory of Biocatalysis, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 311121 Zhejiang China
| | - Jin He
- Laboratory of Biocatalysis, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 311121 Zhejiang China
| | - Zhiguo Wang
- Laboratory of Biocatalysis, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 311121 Zhejiang China
- Institute of Ageing Research, School of Basic Medical Sciences, Hangzhou Normal University, Hangzhou, 311121 Zhejiang China
| | - Zhenming Chen
- Laboratory of Biocatalysis, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 311121 Zhejiang China
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Shi L, Liu P, Tan Z, Zhao W, Gao J, Gu Q, Ma H, Liu H, Zhu L. Complete Depolymerization of PET Wastes by an Evolved PET Hydrolase from Directed Evolution. Angew Chem Int Ed Engl 2023; 62:e202218390. [PMID: 36751696 DOI: 10.1002/anie.202218390] [Citation(s) in RCA: 24] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 02/02/2023] [Accepted: 02/07/2023] [Indexed: 02/09/2023]
Abstract
PETase displays great potential in PET depolymerization. Directed evolution has been limited to engineer PETase due to the lack of high-throughput screening assay. In this study, a novel fluorescence-based high-throughput screening assay employing a newly designed substrate, bis (2-hydroxyethyl) 2-hydroxyterephthalate (termed BHET-OH), was developed for PET hydrolases. The best variant DepoPETase produced 1407-fold more products towards amorphous PET film at 50 °C and showed a 23.3 °C higher Tm value than the PETase WT. DepoPETase enabled complete depolymerization of seven untreated PET wastes and 19.1 g PET waste (0.4 % Wenzyme /WPET ) in liter-scale reactor, suggesting that it is a potential candidate for industrial PET depolymerization processes. The molecular dynamic simulations revealed that the distal substitutions stabilized the loops around the active sites and transmitted the stabilization effect to the active sites through enhancing inter-loop interactions network.
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Affiliation(s)
- Lixia Shi
- University of Chinese Academy of Sciences, 19A Yuquan Road, Beijing, 100049, China
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, P. R. China
- National Technology Innovation Center of Synthetic Biology, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, P. R. China
| | - Pi Liu
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, P. R. China
- National Technology Innovation Center of Synthetic Biology, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, P. R. China
| | - Zijian Tan
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, P. R. China
- Jiangsu Collaborative Innovation Centre of Chinese Medicinal Resources Industrialization, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Wei Zhao
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, P. R. China
- National Technology Innovation Center of Synthetic Biology, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, P. R. China
| | - Junfei Gao
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, P. R. China
- National Technology Innovation Center of Synthetic Biology, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, P. R. China
| | - Qun Gu
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, P. R. China
- National Technology Innovation Center of Synthetic Biology, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, P. R. China
| | - Hongwu Ma
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, P. R. China
- National Technology Innovation Center of Synthetic Biology, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, P. R. China
| | - Haifeng Liu
- Jiangsu Collaborative Innovation Centre of Chinese Medicinal Resources Industrialization, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Leilei Zhu
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, P. R. China
- National Technology Innovation Center of Synthetic Biology, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, P. R. China
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25
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Bohre A, Jadhao PR, Tripathi K, Pant KK, Likozar B, Saha B. Chemical Recycling Processes of Waste Polyethylene Terephthalate Using Solid Catalysts. CHEMSUSCHEM 2023:e202300142. [PMID: 36972065 DOI: 10.1002/cssc.202300142] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 03/27/2023] [Accepted: 03/27/2023] [Indexed: 05/28/2023]
Abstract
Polyethylene terephthalate (PET) is a non-degradable single-use plastic and a major component of plastic waste in landfills. Chemical recycling is one of the most widely adopted methods to transform post-consumer PET into PET's building block chemicals. Non-catalytic depolymerization of PET is very slow and requires high temperatures and/or pressures. Recent advancements in the field of material science and catalysis have delivered several innovative strategies to promote PET depolymerization under mild reaction conditions. Particularly, heterogeneous catalysts assisted depolymerization of post-consumer PET to monomers and other value-added chemicals is the most industrially compatible method. This review includes current progresses on the heterogeneously catalyzed chemical recycling of PET. It describes four key pathways for PET depolymerization including, glycolysis, pyrolysis, alcoholysis, and reductive depolymerization. The catalyst function, active sites and structure-activity correlations are briefly outlined in each section. An outlook for future development is also presented.
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Affiliation(s)
- Ashish Bohre
- Department of Chemical Engineering, Indian Institute of Technology Delhi, Delhi, 110016, India
- Biomass and Energy Management Division, Sardar Swaran Singh National Institute of Bio-energy Kapurthala, Punjab, 1440603, India
- Department of Catalysis and Chemical Reaction Engineering, National Institute of Chemistry, Hajdrihova 19, 1001, Ljubljana, Slovenia
| | - Prashant Ram Jadhao
- Department of Chemical Engineering, Indian Institute of Technology Delhi, Delhi, 110016, India
| | - Komal Tripathi
- Department of Chemical Engineering, Indian Institute of Technology Delhi, Delhi, 110016, India
| | - Kamal Kishore Pant
- Department of Chemical Engineering, Indian Institute of Technology Delhi, Delhi, 110016, India
| | - Blaž Likozar
- Department of Catalysis and Chemical Reaction Engineering, National Institute of Chemistry, Hajdrihova 19, 1001, Ljubljana, Slovenia
| | - Basudeb Saha
- RiKarbon, Inc., 550 S. College Ave, Newark, Delaware, DE 19716, USA
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26
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Determinants for an Efficient Enzymatic Catalysis in Poly(Ethylene Terephthalate) Degradation. Catalysts 2023. [DOI: 10.3390/catal13030591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023] Open
Abstract
The enzymatic degradation of the recalcitrant poly(ethylene terephthalate) (PET) has been an important biotechnological goal. The present review focuses on the state of the art in enzymatic degradation of PET, and the challenges ahead. This review covers (i) enzymes acting on PET, (ii) protein improvements through selection or engineering, (iii) strategies to improve biocatalyst–polymer interaction and monomer yields. Finally, this review discusses critical points on PET degradation, and their related experimental aspects, that include the control of physicochemical parameters. The search for, and engineering of, PET hydrolases, have been widely studied to achieve this, and several examples are discussed here. Many enzymes, from various microbial sources, have been studied and engineered, but recently true PET hydrolases (PETases), active at moderate temperatures, were reported. For a circular economy process, terephtalic acid (TPA) production is critical. Some thermophilic cutinases and engineered PETases have been reported to release terephthalic acid in significant amounts. Some bottlenecks in enzyme performance are discussed, including enzyme activity, thermal stability, substrate accessibility, PET microstructures, high crystallinity, molecular mass, mass transfer, and efficient conversion into reusable fragments.
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27
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Schaerer LG, Wu R, Putman LI, Pearce JM, Lu T, Shonnard DR, Ong RG, Techtmann SM. Killing two birds with one stone: chemical and biological upcycling of polyethylene terephthalate plastics into food. Trends Biotechnol 2023; 41:184-196. [PMID: 36058768 DOI: 10.1016/j.tibtech.2022.06.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2022] [Revised: 05/24/2022] [Accepted: 06/21/2022] [Indexed: 01/24/2023]
Abstract
Most polyethylene terephthalate (PET) plastic waste is landfilled or pollutes the environment. Additionally, global food production must increase to support the growing population. This article explores the feasibility of using microorganisms in an industrial system that upcycles PET into edible microbial protein powder to solve both problems simultaneously. Many microorganisms can utilize plastics as feedstock, and the resultant microbial biomass contains fats, nutrients, and proteins similar to those found in human diets. While microbial degradation of PET is promising, biological PET depolymerization is too slow to resolve the global plastic crisis and projected food shortages. Evidence reviewed here suggests that by coupling chemical depolymerization and biological degradation of PET, and using cooperative microbial communities, microbes can efficiently convert PET waste into food.
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Affiliation(s)
- Laura G Schaerer
- Department of Biological Sciences, Michigan Technological University, Houghton, MI, USA
| | - Ruochen Wu
- Department of Chemical Engineering, Michigan Technological University, Houghton, MI, USA
| | - Lindsay I Putman
- Department of Biological Sciences, Michigan Technological University, Houghton, MI, USA
| | - Joshua M Pearce
- Department of Electrical and Computer Engineering, Western University, London, Ontario, Canada
| | - Ting Lu
- Department of Bioengineering, University of Illinois Urbana-Champaign, Champaign, IL, USA
| | - David R Shonnard
- Department of Chemical Engineering, Michigan Technological University, Houghton, MI, USA
| | - Rebecca G Ong
- Department of Chemical Engineering, Michigan Technological University, Houghton, MI, USA
| | - Stephen M Techtmann
- Department of Biological Sciences, Michigan Technological University, Houghton, MI, USA.
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28
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Development of a yeast whole-cell biocatalyst for MHET conversion into terephthalic acid and ethylene glycol. Microb Cell Fact 2022; 21:280. [PMID: 36587193 PMCID: PMC9805092 DOI: 10.1186/s12934-022-02007-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 12/20/2022] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Over the 70 years since the introduction of plastic into everyday items, plastic waste has become an increasing problem. With over 360 million tonnes of plastics produced every year, solutions for plastic recycling and plastic waste reduction are sorely needed. Recently, multiple enzymes capable of degrading PET (polyethylene terephthalate) plastic have been identified and engineered. In particular, the enzymes PETase and MHETase from Ideonella sakaiensis depolymerize PET into the two building blocks used for its synthesis, ethylene glycol (EG) and terephthalic acid (TPA). Importantly, EG and TPA can be re-used for PET synthesis allowing complete and sustainable PET recycling. RESULTS In this study we used Saccharomyces cerevisiae, a species utilized widely in bioindustrial fermentation processes, as a platform to develop a whole-cell catalyst expressing the MHETase enzyme, which converts monohydroxyethyl terephthalate (MHET) into TPA and EG. We assessed six expression architectures and identified those resulting in efficient MHETase expression on the yeast cell surface. We show that the MHETase whole-cell catalyst has activity comparable to recombinant MHETase purified from Escherichia coli. Finally, we demonstrate that surface displayed MHETase is active across a range of pHs, temperatures, and for at least 12 days at room temperature. CONCLUSIONS We demonstrate the feasibility of using S. cerevisiae as a platform for the expression and surface display of PET degrading enzymes and predict that the whole-cell catalyst will be a viable alternative to protein purification-based approaches for plastic degradation.
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Biodegradation of highly crystallized poly(ethylene terephthalate) through cell surface codisplay of bacterial PETase and hydrophobin. Nat Commun 2022; 13:7138. [PMID: 36414665 PMCID: PMC9681837 DOI: 10.1038/s41467-022-34908-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 11/10/2022] [Indexed: 11/23/2022] Open
Abstract
The process of recycling poly(ethylene terephthalate) (PET) remains a major challenge due to the enzymatic degradation of high-crystallinity PET (hcPET). Recently, a bacterial PET-degrading enzyme, PETase, was found to have the ability to degrade the hcPET, but with low enzymatic activity. Here we present an engineered whole-cell biocatalyst to simulate both the adsorption and degradation steps in the enzymatic degradation process of PETase to achieve the efficient degradation of hcPET. Our data shows that the adhesive unit hydrophobin and degradation unit PETase are functionally displayed on the surface of yeast cells. The turnover rate of the whole-cell biocatalyst toward hcPET (crystallinity of 45%) dramatically increases approximately 328.8-fold compared with that of purified PETase at 30 °C. In addition, molecular dynamics simulations explain how the enhanced adhesion can promote the enzymatic degradation of PET. This study demonstrates engineering the whole-cell catalyst is an efficient strategy for biodegradation of PET.
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30
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Yin Q, You S, Zhang J, Qi W, Su R. Enhancement of the polyethylene terephthalate and mono-(2-hydroxyethyl) terephthalate degradation activity of Ideonella sakaiensis PETase by an electrostatic interaction-based strategy. BIORESOURCE TECHNOLOGY 2022; 364:128026. [PMID: 36174890 DOI: 10.1016/j.biortech.2022.128026] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 09/20/2022] [Accepted: 09/21/2022] [Indexed: 06/16/2023]
Abstract
The serious environmental pollution that came up with the continuously growing demand for polyethylene terephthalate (PET) has attracted global concern. The IsPETase which has shown the highest PET degradation activity under ambient temperature is a promising enzyme for PET biodegradation, while poor thermostability limited its practical application. Herein, an electrostatic interaction-based strategy was applied for rational design of IsPETase towards enhanced thermostability. The IsPETaseI139R variant displayed the highest Tm value of 56.4 °C and 3.6-times higher PET degradation activity. Molecular simulations demonstrated that the introduction of salt bridges stabilized the local structures, resulting in robust thermostability. Meanwhile, the IsPETaseS92K/D157E/R251A not only exhibited higher thermostability but also showed a 1.74-fold kcat increase towards mono-(2-hydroxyethyl) terephthalate, which ultimately achieved PET depolymerization to complete monomer TPA. Collectively, the electrostatic interaction-based strategy, together with the derived IsPETase variants, could help promote the bio-recycle of PET, reducing the severe global burden of PET waste.
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Affiliation(s)
- Qingdian Yin
- Chemical Engineering Research Center, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, PR China
| | - Shengping You
- Chemical Engineering Research Center, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, PR China; Tianjin Key Laboratory of Membrane Science and Desalination Technology, Tianjin University, Tianjin 300072, PR China
| | - Jiaxing Zhang
- Chemical Engineering Research Center, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, PR China
| | - Wei Qi
- Chemical Engineering Research Center, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, PR China; State Key Laboratory of Chemical Engineering, Tianjin University, Tianjin 300350, PR China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, PR China; Tianjin Key Laboratory of Membrane Science and Desalination Technology, Tianjin University, Tianjin 300072, PR China.
| | - Rongxin Su
- Chemical Engineering Research Center, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300350, PR China; State Key Laboratory of Chemical Engineering, Tianjin University, Tianjin 300350, PR China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, PR China; Tianjin Key Laboratory of Membrane Science and Desalination Technology, Tianjin University, Tianjin 300072, PR China
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31
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Zhou J, Sun J, Ullah M, Wang Q, Zhang Y, Cao G, Chen L, Ullah MW, Sun S. Polyethylene terephthalate hydrolysate increased bacterial cellulose production. Carbohydr Polym 2022; 300:120301. [DOI: 10.1016/j.carbpol.2022.120301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 10/28/2022] [Accepted: 10/31/2022] [Indexed: 11/06/2022]
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32
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Hwang DH, Lee ME, Cho BH, Oh JW, You SK, Ko YJ, Hyeon JE, Han SO. Enhanced biodegradation of waste poly(ethylene terephthalate) using a reinforced plastic degrading enzyme complex. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 842:156890. [PMID: 35753492 DOI: 10.1016/j.scitotenv.2022.156890] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 05/28/2022] [Accepted: 06/18/2022] [Indexed: 06/15/2023]
Abstract
Poly(ethylene terephthalate) (PET) is synthesized via a rich ester bond between terephthalate (TPA) and ethylene glycol (EG). Because of this, PET degradation takes a long time and PET accumulates in the environment. Many studies have been conducted to improve PET degrading enzyme to increase the efficiency of PET depolymerization. However, enzymatic PET decomposition is still restricted, making upcycling and recycling difficult. Here, we report a novel PET degrading complex composed of Ideonella sakaiensis PETase and Candida antarctica lipase B (CALB) that improves degradability, binding ability and enzyme stability. The reaction mechanism of chimeric PETase (cPETase) and chimeric CALB (cCALB) was confirmed by PET and bis (2-hydroxyethyl terephthalate) (BHET). cPETase generated BHET and mono (2-hydroxyethyl terephthalate (MHET) and cCALB produced terephthalate (TPA). Carbohydrate binding module 3 (CBM3) in the scaffolding protein greatly improved PET film binding affinity. Finally, the final enzyme complex demonstrated a 6.5-fold and 8.0-fold increase in the efficiency of hydrolysis from PET with either high crystalline or waste to TPA than single enzymes, respectively. This complex could effectively break down waste PET while maintaining enzyme stability and would be applied for biological upcycling of TPA.
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Affiliation(s)
- Dong-Hyeok Hwang
- Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Myeong-Eun Lee
- Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Byeong-Hyeon Cho
- Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Jun Won Oh
- Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Seung Kyou You
- Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Young Jin Ko
- Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Jeong Eun Hyeon
- Department of Food Science and Biotechnology, College of Knowledge-Based Services Engineering, Sungshin Women's University, Seoul 01133, Republic of Korea; Department of Next Generation Applied Sciences, The Graduate School of Sungshin University, Seoul 01133, Republic of Korea
| | - Sung Ok Han
- Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea.
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33
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Microbial degradation of polyethylene terephthalate: a systematic review. SN APPLIED SCIENCES 2022. [DOI: 10.1007/s42452-022-05143-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
AbstractPlastic pollution levels have increased rapidly in recent years, due to the accumulation of plastic waste, including polyethylene terephthalate (PET). Both high production and the lack of efficient methods for disposal and recycling affect diverse aquatic and terrestrial ecosystems owing to the high accumulation rates of plastics. Traditional chemical and physical degradation techniques have caused adverse effects on the environment; hence, the use of microorganisms for plastic degradation has gained importance recently. This systematic review was conducted for evaluating the reported findings about PET degradation by wild and genetically modified microorganisms to make them available for future work and to contribute to the eventual implementation of an alternative, an effective, and environmentally friendly method for the management of plastic waste such as PET. Both wild and genetically modified microorganisms with the metabolic potential to degrade this polymer were identified, in addition to the enzymes and genes used for genetic modification. The most prevalent wild-type PET-degrading microorganisms were bacteria (56.3%, 36 genera), followed by fungi (32.4%, 30 genera), microalgae (1.4%; 1 genus, namely Spirulina sp.), and invertebrate associated microbiota (2.8%). Among fungi and bacteria, the most prevalent genera were Aspergillus sp. and Bacillus sp., respectively. About genetically modified microorganisms, 50 strains of Escherichia coli, most of them expressing PETase enzyme, have been used. We emphasize the pressing need for implementing biological techniques for PET waste management on a commercial scale, using consortia of microorganisms. We present this work in five sections: an Introduction that highlights the importance of PET biodegradation as an effective and sustainable alternative, a section on Materials and methods that summarizes how the search for articles and manuscripts in different databases was done, and another Results section where we present the works found on the subject, a final part of Discussion and analysis of the literature found and finally we present a Conclusion and prospects.
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34
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Jia Y, Samak NA, Hao X, Chen Z, Wen Q, Xing J. Hydrophobic cell surface display system of PETase as a sustainable biocatalyst for PET degradation. Front Microbiol 2022; 13:1005480. [PMID: 36246227 PMCID: PMC9559558 DOI: 10.3389/fmicb.2022.1005480] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 09/14/2022] [Indexed: 02/02/2023] Open
Abstract
Remarkably, a hydrolase from Ideonella sakaiensis 201-F6, termed PETase, exhibits great potential in polyethylene terephthalate (PET) waste management due to it can efficiently degrade PET under moderate conditions. However, its low yield and poor accessibility to bulky substrates hamper its further industrial application. Herein a multigene fusion strategy is introduced for constructing a hydrophobic cell surface display (HCSD) system in Escherichia coli as a robust, recyclable, and sustainable whole-cell catalyst. The truncated outer membrane hybrid protein FadL exposed the PETase and hydrophobic protein HFBII on the surface of E. coli with efficient PET accessibility and degradation performance. E. coli containing the HCSD system changed the surface tension of the bacterial solution, resulting in a smaller contact angle (83.9 ± 2° vs. 58.5 ± 1°) of the system on the PET surface, thus giving a better opportunity for PETase to interact with PET. Furthermore, pretreatment of PET with HCSD showed rougher surfaces with greater hydrophilicity (water contact angle of 68.4 ± 1° vs. 106.1 ± 2°) than the non-pretreated ones. Moreover, the HCSD system showed excellent sustainable degradation performance for PET bottles with a higher degradation rate than free PETase. The HCSD degradation system also had excellent stability, maintaining 73% of its initial activity after 7 days of incubation at 40°C and retaining 70% activity after seven cycles. This study indicates that the HCSD system could be used as a novel catalyst for efficiently accelerating PET biodegradation.
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Affiliation(s)
- Yunpu Jia
- CAS Key Laboratory of Green Process and Engineering, State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China
- College of Chemical Engineering, University of Chinese Academy of Sciences, Beijing, China
| | - Nadia A. Samak
- Environmental Microbiology and Biotechnology, Aquatic Microbiology, University of Duisburg-Essen, Essen, Germany
| | - Xuemi Hao
- CAS Key Laboratory of Green Process and Engineering, State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China
- College of Chemical Engineering, University of Chinese Academy of Sciences, Beijing, China
| | - Zheng Chen
- CAS Key Laboratory of Green Process and Engineering, State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China
- College of Chemical Engineering, University of Chinese Academy of Sciences, Beijing, China
| | - Qifeng Wen
- CAS Key Laboratory of Green Process and Engineering, State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China
- College of Chemical Engineering, University of Chinese Academy of Sciences, Beijing, China
| | - Jianmin Xing
- CAS Key Laboratory of Green Process and Engineering, State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China
- College of Chemical Engineering, University of Chinese Academy of Sciences, Beijing, China
- Chemistry and Chemical Engineering Guangdong Laboratory, Shantou, China
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35
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Aer L, Jiang Q, Gul I, Qi Z, Feng J, Tang L. Overexpression and kinetic analysis of Ideonella sakaiensis PETase for polyethylene terephthalate (PET) degradation. ENVIRONMENTAL RESEARCH 2022; 212:113472. [PMID: 35577005 DOI: 10.1016/j.envres.2022.113472] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 05/08/2022] [Accepted: 05/10/2022] [Indexed: 06/15/2023]
Abstract
Ideonella sakaiensis PET hydrolase (IsPETase) is a well-characterized enzyme for effective PET biodegradation. However, the low soluble expression level of the enzyme hampers its practical implementation in the biodegradation of PET. Herein, the expression of IsPETaseMut, one of the most active mutants of IsPETase obtained so far, was systematically explored in E. coli by adopting a series of strategies. A notable improvement of soluble IsPETaseMut was observed by using chaperon co-expression and fusion expression systems. Under the optimized conditions, GroEL/ES co-expression system yielded 75 ± 3.4 mg·L-1 purified soluble IsPETaseMut (GroEL/ES), and NusA fusion expression system yielded 80 ± 3.7 mg·L-1 purified soluble NusA-IsPETaseMut, which are 12.5- and 4.6-fold, respectively, higher than its commonly expression in E. coli. The two purified enzymes were further characterized. The results showed that IsPETaseMut (GroEL/ES) displayed the same catalytic behavior as IsPETaseMut, while the fusion of NusA conferred new enzymatic properties to IsPETaseMut. Although NusA-IsPETaseMut displayed a lower initial hydrolysis capacity than IsPETaseMut, it showed a 1.4-fold higher adsorption constant toward PET. Moreover, the product inhibition effect of terephthalic acid (TPA) on IsPETase was reduced with NusA-IsPETaseMut. Taken together, the latter two catalytic properties of NusA-IsPETaseMut are more likely to contribute to the enhanced product release by NusA-IsPETaseMut PET degradation for two weeks.
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Affiliation(s)
- Lizhu Aer
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Qifa Jiang
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Ijaz Gul
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, 610054, China; Institute of Biopharmaceutical and Health Engineering, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, PR China
| | - Zixuan Qi
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Juan Feng
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, 610054, China; Center for Informational Biology, University of Electronic Science and Technology of China, Chengdu, 610054, China
| | - Lixia Tang
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu, 610054, China; Center for Informational Biology, University of Electronic Science and Technology of China, Chengdu, 610054, China.
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36
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Tang KHD, Lock SSM, Yap PS, Cheah KW, Chan YH, Yiin CL, Ku AZE, Loy ACM, Chin BLF, Chai YH. Immobilized enzyme/microorganism complexes for degradation of microplastics: A review of recent advances, feasibility and future prospects. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 832:154868. [PMID: 35358520 DOI: 10.1016/j.scitotenv.2022.154868] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 03/23/2022] [Accepted: 03/23/2022] [Indexed: 06/14/2023]
Abstract
Environmental prevalence of microplastics has prompted the development of novel methods for their removal, one of which involves immobilization of microplastics-degrading enzymes. Various materials including nanomaterials have been studied for this purpose but there is currently a lack of review to present these studies in an organized manner to highlight the advances and feasibility. This article reviewed more than 100 peer-reviewed scholarly papers to elucidate the latest advances in the novel application of immobilized enzyme/microorganism complexes for microplastics degradation, its feasibility and future prospects. This review shows that metal nanoparticle-enzyme complexes improve biodegradation of microplastics in most studies through creating photogenerated radicals to facilitate polymer oxidation, accelerating growth of bacterial consortia for biodegradation, anchoring enzymes and improving their stability, and absorbing water for hydrolysis. In a study, the antimicrobial property of nanoparticles retarded the growth of microorganisms, hence biodegradation. Carbon particle-enzyme complexes enable enzymes to be immobilized on carbon-based support or matrix through covalent bonding, adsorption, entrapment, encapsulation, and a combination of the mechanisms, facilitated by formation of cross-links between enzymes. These complexes were shown to improve microplastics-degrading efficiency and recyclability of enzymes. Other emerging nanoparticles and/or enzymatic technologies are fusion of enzymes with hydrophobins, polymer binding module, peptide and novel nanoparticles. Nonetheless, the enzymes in the complexes present a limiting factor due to limited understanding of the degradation mechanisms. Besides, there is a lack of studies on the degradation of polypropylene and polyvinyl chloride. Genetic bioengineering and metagenomics could provide breakthrough in this area. This review highlights the optimism of using immobilized enzymes/microorganisms to increase the efficiency of microplastics degradation but optimization of enzymatic or microbial activities and synthesis of immobilized enzymes/microorganisms are crucial to overcome the barriers to their wide application.
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Affiliation(s)
- Kuok Ho Daniel Tang
- Environmental Science Program, Division of Science and Technology, Beijing Normal University-Hong Kong Baptist University United International College, Zhuhai 519087, China.
| | - Serene Sow Mun Lock
- CO2 Research Center (CO2RES), Department of Chemical Engineering, Universiti Teknologi PETRONAS, 32610 Seri Iskandar, Malaysia
| | - Pow-Seng Yap
- Department of Civil Engineering, Xi'an Jiaotong-Liverpool University, Suzhou 215123, China
| | - Kin Wai Cheah
- Computing, Engineering and Digital Technologies, Teesside University, Middlesbrough TS1 3BX, United Kingdom
| | - Yi Herng Chan
- PETRONAS Research Sdn. Bhd. (PRSB), Lot 3288 & 3289, Off Jalan Ayer Itam, Kawasan Institusi Bangi, 43000 Kajang, Selangor, Malaysia
| | - Chung Loong Yiin
- Department of Chemical Engineering and Energy Sustainability, Faculty of Engineering, Universiti Malaysia Sarawak (UNIMAS), Kota Samarahan 94300, Sarawak, Malaysia
| | - Andrian Zi En Ku
- Department of Chemical Engineering and Energy Sustainability, Faculty of Engineering, Universiti Malaysia Sarawak (UNIMAS), Kota Samarahan 94300, Sarawak, Malaysia
| | - Adrian Chun Minh Loy
- Department of Chemical Engineering, Monash University, Clayton, VIC 3800, Australia
| | - Bridgid Lai Fui Chin
- Department of Chemical and Energy Engineering, Faculty of Engineering and Science, Curtin University Malaysia, CDT 250, 98009 Miri, Sarawak, Malaysia
| | - Yee Ho Chai
- HICoE-Centre for Biofuel and Biochemical Research, Institute of Self-Sustainable Building, Department of Chemical Engineering, Universiti Teknologi PETRONAS, 32610 Seri Iskandar, Perak, Malaysia
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Saito H, Ueda M, Aoki W. Enhancement of PET degradation by PET depolymerase with the microbe addition. Biosci Biotechnol Biochem 2022; 86:1482-1484. [PMID: 35881488 DOI: 10.1093/bbb/zbac129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Accepted: 07/20/2022] [Indexed: 11/13/2022]
Abstract
The degradation of polyethylene terephthalate (PET) by modified PET depolymerase has recently attracted much attention. We found that mixing a PET depolymerase with non-genetically modified Thermus sp. can enhance its PET-degrading activity by 7.7-fold. This approach is attractive for constructing a sustainable PET recycling system.
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Affiliation(s)
- Hiroki Saito
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Mitsuyoshi Ueda
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Wataru Aoki
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
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Shilpa, Basak N, Meena SS. Microbial biodegradation of plastics: Challenges, opportunities, and a critical perspective. FRONTIERS OF ENVIRONMENTAL SCIENCE & ENGINEERING 2022; 16:161. [PMID: 35874797 PMCID: PMC9295099 DOI: 10.1007/s11783-022-1596-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Revised: 06/18/2022] [Accepted: 06/20/2022] [Indexed: 05/19/2023]
Abstract
The abundance of synthetic polymers has increased due to their uncontrolled utilization and disposal in the environment. The recalcitrant nature of plastics leads to accumulation and saturation in the environment, which is a matter of great concern. An exponential rise has been reported in plastic pollution during the corona pandemic because of PPE kits, gloves, and face masks made up of single-use plastics. The physicochemical methods have been employed to degrade synthetic polymers, but these methods have limited efficiency and cause the release of hazardous metabolites or by-products in the environment. Microbial species, isolated from landfills and dumpsites, have utilized plastics as the sole source of carbon, energy, and biomass production. The involvement of microbial strains in plastic degradation is evident as a substantial amount of mineralization has been observed. However, the complete removal of plastic could not be achieved, but it is still effective compared to the preexisting traditional methods. Therefore, microbial species and the enzymes involved in plastic waste degradation could be utilized as eco-friendly alternatives. Thus, microbial biodegradation approaches have a profound scope to cope with the plastic waste problem in a cost-effective and environmental-friendly manner. Further, microbial degradation can be optimized and combined with physicochemical methods to achieve substantial results. This review summarizes the different microbial species, their genes, biochemical pathways, and enzymes involved in plastic biodegradation.
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Affiliation(s)
- Shilpa
- Department of Biotechnology, Dr. B. R. Ambedkar National Institute of Technology Jalandhar, Punjab, 144027 India
| | - Nitai Basak
- Department of Biotechnology, Dr. B. R. Ambedkar National Institute of Technology Jalandhar, Punjab, 144027 India
| | - Sumer Singh Meena
- Department of Biotechnology, Dr. B. R. Ambedkar National Institute of Technology Jalandhar, Punjab, 144027 India
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Reinforced distiller’s grains as bio-fillers in environment-friendly poly(ethylene terephthalate) composites. Polym Bull (Berl) 2022. [DOI: 10.1007/s00289-022-04318-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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40
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Li Z, Li W, Wang Y, Chen Z, Nakanishi H, Xu X, Gao XD. Establishment of a Novel Cell Surface Display Platform Based on Natural "Chitosan Beads" of Yeast Spores. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:7479-7489. [PMID: 35678723 DOI: 10.1021/acs.jafc.2c01983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Cell surface display technology, which expresses and anchors proteins on the surface of microbial cells, has broad application prospects in many fields, such as protein library screening, biocatalysis, and biosensor development. However, traditional cell surface display systems have disadvantages: the molecular weight of phage display proteins cannot be too large; bacterial display lacks the post-translational modification process for eukaryotic proteins; yeast display is prone to excessive protein glycosylation and misfolding of multisubunit proteins; and the compatibility of Bacillus subtilis spore display needs to be further improved. Therefore, it is extremely valuable to develop an efficient surface display platform with strong universality and stress resistance properties. Although yeast surface display systems have been extensively investigated, the establishment of a surface display platform using yeast spores has rarely been reported. In this study, a novel cell surface display platform based on natural "chitosan beads" of yeast spores was developed. The target protein in fusion with the chitosan affinity protein (CAP) exhibited strong binding capability with "chitosan beads" of yeast spores in vitro and in vivo. Moreover, this protein display system showed highly preferable enzymatic properties and stability. As an example, the displayed LXYL-P1-2-CAP demonstrated high thermostability and reusability (60% of the initial activity after seven cycles of reuse), high storage stability (75% of original activity after 8 weeks), and excellent tolerance to a concentration up to 75% (v/v) organic reagents. To prove the practicability of this surface display system, the semisynthesis of paclitaxel intermediate was demonstrated and its highest conversion rate was 92% using 0.25 mM substrate. This study provides a novel and useful platform for the surface display of proteins, especially for multimeric macromolecular proteins of eukaryotic origin.
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Affiliation(s)
- Zijie Li
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, Jiangsu, China
| | - Wanjie Li
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, Jiangsu, China
| | - Yasen Wang
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, Jiangsu, China
| | - Zhou Chen
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, Jiangsu, China
| | - Hideki Nakanishi
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, Jiangsu, China
| | - Xiangyang Xu
- Zaozhuang Jienuo Enzyme Co., Ltd., Zaozhuang 277100, China
| | - Xiao-Dong Gao
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi 214122, Jiangsu, China
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Brandenberg OF, Schubert OT, Kruglyak L. Towards synthetic PETtrophy: Engineering Pseudomonas putida for concurrent polyethylene terephthalate (PET) monomer metabolism and PET hydrolase expression. Microb Cell Fact 2022; 21:119. [PMID: 35717313 PMCID: PMC9206389 DOI: 10.1186/s12934-022-01849-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 05/26/2022] [Indexed: 12/27/2022] Open
Abstract
BACKGROUND Biocatalysis offers a promising path for plastic waste management and valorization, especially for hydrolysable plastics such as polyethylene terephthalate (PET). Microbial whole-cell biocatalysts for simultaneous PET degradation and growth on PET monomers would offer a one-step solution toward PET recycling or upcycling. We set out to engineer the industry-proven bacterium Pseudomonas putida for (i) metabolism of PET monomers as sole carbon sources, and (ii) efficient extracellular expression of PET hydrolases. We pursued this approach for both PET and the related polyester polybutylene adipate co-terephthalate (PBAT), aiming to learn about the determinants and potential applications of bacterial polyester-degrading biocatalysts. RESULTS P. putida was engineered to metabolize the PET and PBAT monomer terephthalic acid (TA) through genomic integration of four tphII operon genes from Comamonas sp. E6. Efficient cellular TA uptake was enabled by a point mutation in the native P. putida membrane transporter MhpT. Metabolism of the PET and PBAT monomers ethylene glycol and 1,4-butanediol was achieved through adaptive laboratory evolution. We then used fast design-build-test-learn cycles to engineer extracellular PET hydrolase expression, including tests of (i) the three PET hydrolases LCC, HiC, and IsPETase; (ii) genomic versus plasmid-based expression, using expression plasmids with high, medium, and low cellular copy number; (iii) three different promoter systems; (iv) three membrane anchor proteins for PET hydrolase cell surface display; and (v) a 30-mer signal peptide library for PET hydrolase secretion. PET hydrolase surface display and secretion was successfully engineered but often resulted in host cell fitness costs, which could be mitigated by promoter choice and altering construct copy number. Plastic biodegradation assays with the best PET hydrolase expression constructs genomically integrated into our monomer-metabolizing P. putida strains resulted in various degrees of plastic depolymerization, although self-sustaining bacterial growth remained elusive. CONCLUSION Our results show that balancing extracellular PET hydrolase expression with cellular fitness under nutrient-limiting conditions is a challenge. The precise knowledge of such bottlenecks, together with the vast array of PET hydrolase expression tools generated and tested here, may serve as a baseline for future efforts to engineer P. putida or other bacterial hosts towards becoming efficient whole-cell polyester-degrading biocatalysts.
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Affiliation(s)
- Oliver F Brandenberg
- Department of Human Genetics, Department of Biological Chemistry, and Howard Hughes Medical Institute, University of California Los Angeles, Los Angeles, USA.
| | - Olga T Schubert
- Department of Human Genetics, Department of Biological Chemistry, and Howard Hughes Medical Institute, University of California Los Angeles, Los Angeles, USA.,Department of Environmental Microbiology, EAWAG, 8600, Dübendorf, Switzerland.,Department of Environmental Systems Science, ETH Zurich, 8092, Zürich, Switzerland
| | - Leonid Kruglyak
- Department of Human Genetics, Department of Biological Chemistry, and Howard Hughes Medical Institute, University of California Los Angeles, Los Angeles, USA.
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42
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Barcoto MO, Rodrigues A. Lessons From Insect Fungiculture: From Microbial Ecology to Plastics Degradation. Front Microbiol 2022; 13:812143. [PMID: 35685924 PMCID: PMC9171207 DOI: 10.3389/fmicb.2022.812143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 03/15/2022] [Indexed: 11/13/2022] Open
Abstract
Anthropogenic activities have extensively transformed the biosphere by extracting and disposing of resources, crossing boundaries of planetary threat while causing a global crisis of waste overload. Despite fundamental differences regarding structure and recalcitrance, lignocellulose and plastic polymers share physical-chemical properties to some extent, that include carbon skeletons with similar chemical bonds, hydrophobic properties, amorphous and crystalline regions. Microbial strategies for metabolizing recalcitrant polymers have been selected and optimized through evolution, thus understanding natural processes for lignocellulose modification could aid the challenge of dealing with the recalcitrant human-made polymers spread worldwide. We propose to look for inspiration in the charismatic fungal-growing insects to understand multipartite degradation of plant polymers. Independently evolved in diverse insect lineages, fungiculture embraces passive or active fungal cultivation for food, protection, and structural purposes. We consider there is much to learn from these symbioses, in special from the community-level degradation of recalcitrant biomass and defensive metabolites. Microbial plant-degrading systems at the core of insect fungicultures could be promising candidates for degrading synthetic plastics. Here, we first compare the degradation of lignocellulose and plastic polymers, with emphasis in the overlapping microbial players and enzymatic activities between these processes. Second, we review the literature on diverse insect fungiculture systems, focusing on features that, while supporting insects' ecology and evolution, could also be applied in biotechnological processes. Third, taking lessons from these microbial communities, we suggest multidisciplinary strategies to identify microbial degraders, degrading enzymes and pathways, as well as microbial interactions and interdependencies. Spanning from multiomics to spectroscopy, microscopy, stable isotopes probing, enrichment microcosmos, and synthetic communities, these strategies would allow for a systemic understanding of the fungiculture ecology, driving to application possibilities. Detailing how the metabolic landscape is entangled to achieve ecological success could inspire sustainable efforts for mitigating the current environmental crisis.
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Affiliation(s)
- Mariana O. Barcoto
- Center for the Study of Social Insects, São Paulo State University (UNESP), Rio Claro, Brazil
- Department of General and Applied Biology, São Paulo State University (UNESP), Rio Claro, Brazil
| | - Andre Rodrigues
- Center for the Study of Social Insects, São Paulo State University (UNESP), Rio Claro, Brazil
- Department of General and Applied Biology, São Paulo State University (UNESP), Rio Claro, Brazil
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43
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Liu L, Xu M, Ye Y, Zhang B. On the degradation of (micro)plastics: Degradation methods, influencing factors, environmental impacts. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 806:151312. [PMID: 34743885 DOI: 10.1016/j.scitotenv.2021.151312] [Citation(s) in RCA: 82] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 10/25/2021] [Accepted: 10/25/2021] [Indexed: 06/13/2023]
Abstract
Plastics and microplastics are difficult to degrade in the natural environment due to their hydrophobicity, the presence of stable covalent bonds and functional groups that are not susceptible to attack. In nature, microplastics are more likely to attract other substances due to their large specific surface area, which further prevents degradation from occurring. Some of these substances are toxic and harmful, and can be spread to various organisms through the food chain along with the microplastics to cause harm to them. Degradation is an effective way to eliminate plastic pollution, and a comprehensive understanding of the methods and mechanisms of plastic degradation is necessary, because it is the result of synergistic effects of several degradation methods, both in nature and in consideration of future engineering applications. The authors firstly summarize the degradation methods of (micro)plastics; secondly, review the influence of intrinsic properties and environmental factors during the degradation process; finally, discuss the environmental impact of the degradation products of (micro)plastics. It is evident that the degradation of (micro)plastics still has many challenges to overcome, and there are no mature and effective methods that can be applied in engineering practice or widely used in nature. Therefore, there is an urgent need for research on the degradation of (micro)plastics.
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Affiliation(s)
- Lingchen Liu
- School of Architecture and Civil Engineering of Xihua University, Chengdu 610039, PR China
| | - Mingjie Xu
- School of Architecture and Civil Engineering of Xihua University, Chengdu 610039, PR China
| | - Yuheng Ye
- School of Architecture and Civil Engineering of Xihua University, Chengdu 610039, PR China
| | - Bin Zhang
- School of Architecture and Civil Engineering of Xihua University, Chengdu 610039, PR China; School of Food and Biotechnology of Xihua University, Chengdu 610039, PR China.
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44
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Lin K, Han S, Zheng S. Application of Corynebacterium glutamicum engineering display system in three generations of biorefinery. Microb Cell Fact 2022; 21:14. [PMID: 35090458 PMCID: PMC8796525 DOI: 10.1186/s12934-022-01741-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 01/09/2022] [Indexed: 11/29/2022] Open
Abstract
The fermentation production of platform chemicals in biorefineries is a sustainable alternative to the current petroleum refining process. The natural advantages of Corynebacterium glutamicum in carbon metabolism have led to C. glutamicum being used as a microbial cell factory that can use various biomass to produce value-added platform chemicals and polymers. In this review, we discussed the use of C. glutamicum surface display engineering bacteria in the three generations of biorefinery resources, and analyzed the C. glutamicum engineering display system in degradation, transport, and metabolic network reconstruction models. These engineering modifications show that the C. glutamicum engineering display system has great potential to become a cell refining factory based on sustainable biomass, and further optimizes the inherent properties of C. glutamicum as a whole-cell biocatalyst. This review will also provide a reference for the direction of future engineering transformation.
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Affiliation(s)
- Kerui Lin
- Guangdong Key Laboratory of Fermentation and Enzyme Engineering, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, People's Republic of China.,Guangdong Research Center of Industrial Enzyme and Green Manufacturing Technology, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, People's Republic of China
| | - Shuangyan Han
- Guangdong Key Laboratory of Fermentation and Enzyme Engineering, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, People's Republic of China.,Guangdong Research Center of Industrial Enzyme and Green Manufacturing Technology, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, People's Republic of China
| | - Suiping Zheng
- Guangdong Key Laboratory of Fermentation and Enzyme Engineering, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, People's Republic of China. .,Guangdong Research Center of Industrial Enzyme and Green Manufacturing Technology, School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, People's Republic of China.
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45
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Qi X, Yan W, Cao Z, Ding M, Yuan Y. Current Advances in the Biodegradation and Bioconversion of Polyethylene Terephthalate. Microorganisms 2021; 10:39. [PMID: 35056486 PMCID: PMC8779501 DOI: 10.3390/microorganisms10010039] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 12/15/2021] [Accepted: 12/20/2021] [Indexed: 01/04/2023] Open
Abstract
Polyethylene terephthalate (PET) is a widely used plastic that is polymerized by terephthalic acid (TPA) and ethylene glycol (EG). In recent years, PET biodegradation and bioconversion have become important in solving environmental plastic pollution. More and more PET hydrolases have been discovered and modified, which mainly act on and degrade the ester bond of PET. The monomers, TPA and EG, can be further utilized by microorganisms, entering the tricarboxylic acid cycle (TCA cycle) or being converted into high value chemicals, and finally realizing the biodegradation and bioconversion of PET. Based on synthetic biology and metabolic engineering strategies, this review summarizes the current advances in the modified PET hydrolases, engineered microbial chassis in degrading PET, bioconversion pathways of PET monomers, and artificial microbial consortia in PET biodegradation and bioconversion. Artificial microbial consortium provides novel ideas for the biodegradation and bioconversion of PET or other complex polymers. It is helpful to realize the one-step bioconversion of PET into high value chemicals.
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Affiliation(s)
- Xinhua Qi
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China; (X.Q.); (W.Y.); (Z.C.); (Y.Y.)
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin 300072, China
| | - Wenlong Yan
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China; (X.Q.); (W.Y.); (Z.C.); (Y.Y.)
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin 300072, China
| | - Zhibei Cao
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China; (X.Q.); (W.Y.); (Z.C.); (Y.Y.)
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin 300072, China
| | - Mingzhu Ding
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China; (X.Q.); (W.Y.); (Z.C.); (Y.Y.)
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin 300072, China
| | - Yingjin Yuan
- Frontier Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering (Ministry of Education), School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China; (X.Q.); (W.Y.); (Z.C.); (Y.Y.)
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin 300072, China
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46
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Qi X, Ma Y, Chang H, Li B, Ding M, Yuan Y. Evaluation of PET Degradation Using Artificial Microbial Consortia. Front Microbiol 2021; 12:778828. [PMID: 35003008 PMCID: PMC8733400 DOI: 10.3389/fmicb.2021.778828] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 12/06/2021] [Indexed: 01/30/2023] Open
Abstract
Polyethylene terephthalate (PET) biodegradation is regarded as an environmentally friendly degradation method. In this study, an artificial microbial consortium composed of Rhodococcus jostii, Pseudomonas putida and two metabolically engineered Bacillus subtilis was constructed to degrade PET. First, a two-species microbial consortium was constructed with two engineered B. subtilis that could secrete PET hydrolase (PETase) and monohydroxyethyl terephthalate hydrolase (MHETase), respectively; it could degrade 13.6% (weight loss) of the PET film within 7 days. A three-species microbial consortium was further obtained by adding R. jostii to reduce the inhibition caused by terephthalic acid (TPA), a breakdown product of PET. The weight of PET film was reduced by 31.2% within 3 days, achieving about 17.6% improvement compared with the two-species microbial consortium. Finally, P. putida was introduced to reduce the inhibition caused by ethylene glycol (EG), another breakdown product of PET, obtaining a four-species microbial consortium. With the four-species consortium, the weight loss of PET film reached 23.2% under ambient temperature. This study constructed and evaluated the artificial microbial consortia in PET degradation, which demonstrated the great potential of artificial microbial consortia in the utilization of complex substrates, providing new insights for biodegradation of complex polymers.
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Affiliation(s)
- Xinhua Qi
- Key Laboratory of Systems Bioengineering (Ministry of Education), Frontier Science Center for Synthetic Biology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin, China
| | - Yuan Ma
- Key Laboratory of Systems Bioengineering (Ministry of Education), Frontier Science Center for Synthetic Biology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin, China
| | - Hanchen Chang
- Key Laboratory of Systems Bioengineering (Ministry of Education), Frontier Science Center for Synthetic Biology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin, China
| | - Bingzhi Li
- Key Laboratory of Systems Bioengineering (Ministry of Education), Frontier Science Center for Synthetic Biology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin, China
| | - Mingzhu Ding
- Key Laboratory of Systems Bioengineering (Ministry of Education), Frontier Science Center for Synthetic Biology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin, China
| | - Yingjin Yuan
- Key Laboratory of Systems Bioengineering (Ministry of Education), Frontier Science Center for Synthetic Biology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin University, Tianjin, China
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47
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Magalhães RP, Cunha JM, Sousa SF. Perspectives on the Role of Enzymatic Biocatalysis for the Degradation of Plastic PET. Int J Mol Sci 2021; 22:11257. [PMID: 34681915 PMCID: PMC8540959 DOI: 10.3390/ijms222011257] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 10/13/2021] [Accepted: 10/16/2021] [Indexed: 12/25/2022] Open
Abstract
Plastics are highly durable and widely used materials. Current methodologies of plastic degradation, elimination, and recycling are flawed. In recent years, biodegradation (the usage of microorganisms for material recycling) has grown as a valid alternative to previously used methods. The evolution of bioengineering techniques and the discovery of novel microorganisms and enzymes with degradation ability have been key. One of the most produced plastics is PET, a long chain polymer of terephthalic acid (TPA) and ethylene glycol (EG) repeating monomers. Many enzymes with PET degradation activity have been discovered, characterized, and engineered in the last few years. However, classification and integrated knowledge of these enzymes are not trivial. Therefore, in this work we present a summary of currently known PET degrading enzymes, focusing on their structural and activity characteristics, and summarizing engineering efforts to improve activity. Although several high potential enzymes have been discovered, further efforts to improve activity and thermal stability are necessary.
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Affiliation(s)
- Rita P. Magalhães
- UCIBIO—Applied Molecular Biosciences Unit, BioSIM—Departamento de Biomedicina, Faculdade de Medicina, Universidade do Porto, 4200-319 Porto, Portugal; (R.P.M.); (J.M.C.)
- Associate Laboratory i4HB—Institute for Health and Bioeconomy, Faculdade de Medicina, Universidade do Porto, 4200-319 Porto, Portugal
| | - Jorge M. Cunha
- UCIBIO—Applied Molecular Biosciences Unit, BioSIM—Departamento de Biomedicina, Faculdade de Medicina, Universidade do Porto, 4200-319 Porto, Portugal; (R.P.M.); (J.M.C.)
- Associate Laboratory i4HB—Institute for Health and Bioeconomy, Faculdade de Medicina, Universidade do Porto, 4200-319 Porto, Portugal
| | - Sérgio F. Sousa
- UCIBIO—Applied Molecular Biosciences Unit, BioSIM—Departamento de Biomedicina, Faculdade de Medicina, Universidade do Porto, 4200-319 Porto, Portugal; (R.P.M.); (J.M.C.)
- Associate Laboratory i4HB—Institute for Health and Bioeconomy, Faculdade de Medicina, Universidade do Porto, 4200-319 Porto, Portugal
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48
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Kumari A, Bano N, Bag SK, Chaudhary DR, Jha B. Transcriptome-Guided Insights Into Plastic Degradation by the Marine Bacterium. Front Microbiol 2021; 12:751571. [PMID: 34646260 PMCID: PMC8503683 DOI: 10.3389/fmicb.2021.751571] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Accepted: 08/30/2021] [Indexed: 11/13/2022] Open
Abstract
Polyethylene terephthalate (PET) is a common single-use plastic that accumulated in the environment because of its non-degradable characteristics. In recent years, microbes from different environments were found to degrade plastics and suggested their capability to degrade plastics under varying environmental conditions. However, complete degradation of plastics is still a void for large-scale implications using microbes because of the lack of knowledge about genes and pathways intricate in the biodegradation process. In the present study, the growth and adherence of marine Bacillus species AIIW2 on PET surface instigating structural deterioration were confirmed through weight loss and hydrophobicity reduction, as well as analyzing the change in bond indexes. The genome-wide comparative transcriptomic analysis of strain AIIW2 was completed to reveal the genes during PET utilization. The expression level of mRNA in the strain AIIW2 was indexed based on the log-fold change between the presence and absence of PET in the culture medium. The genes represent carbon metabolism, and the cell transport system was up-regulated in cells growing with PET, whereas sporulation genes expressed highly in the absence of PET. This indicates that the strain AIIW2 hydrolyzes PET and assimilated via cellular carbon metabolism. A protein-protein interaction network was built to obtain the interaction between genes during PET utilization. The genes traced to degrade PET were confirmed by detecting the hydrolytic product of PET, and genes were cloned to improve PET utilization by microbial system as an eco-friendly solution.
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Affiliation(s)
- Alka Kumari
- Plant Omics Division, CSIR-Central Salt and Marine Chemical Research Institute, Bhavnagar, India
| | - Nasreen Bano
- Academy of Scientific and Innovative Research (AcSIR), CSIR, Ghaziabad, India.,Molecular Biology and Biotechnology, CSIR-National Botanical Research Institute, Lucknow, India
| | - Sumit Kumar Bag
- Academy of Scientific and Innovative Research (AcSIR), CSIR, Ghaziabad, India.,Molecular Biology and Biotechnology, CSIR-National Botanical Research Institute, Lucknow, India
| | - Doongar R Chaudhary
- Plant Omics Division, CSIR-Central Salt and Marine Chemical Research Institute, Bhavnagar, India.,Academy of Scientific and Innovative Research (AcSIR), CSIR, Ghaziabad, India
| | - Bhavanath Jha
- Plant Omics Division, CSIR-Central Salt and Marine Chemical Research Institute, Bhavnagar, India
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49
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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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50
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Ghodke VM, Punekar NS. Environmental role of aromatic carboxylesterases. Environ Microbiol 2021; 24:2657-2668. [PMID: 34528362 DOI: 10.1111/1462-2920.15774] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 09/08/2021] [Accepted: 09/10/2021] [Indexed: 01/14/2023]
Abstract
The carboxylesterases (EC 3.1.1.x) are widely distributed and form an important yet diverse group of hydrolases catalysing the ester bond cleavage in a variety of substrates. Besides acting on plant cell wall components like cutin, tannin and feruloyl esters, they are often the first line of defence to metabolize drugs, xenobiotics, pesticides, insecticides and plastic. But for the promiscuity of some carboxylesterases and cutinases, very few enzymes act exclusively on aromatic carboxylic acid esters. Infrequent occurrence of aromatic carboxylesterases suggests that aromatic carboxylesters are inherently more difficult to hydrolyse than the regular carboxylesters because of both steric and polar effects. Naturally occurring aromatic carboxylesters were rare before the anthropogenic activity augmented their environmental presence and diversity. An appraisal of the literature shows that the hydrolysis of aromatic carboxylic esters is a uniquely difficult endeavour and hence deserves special attention. Enzymes to hydrolyse such esters are evolving rapidly in nature. Very few such enzymes are known and they often display much lower catalytic efficiencies. Obviously, the esters of aromatic carboxylic acids, including polyethylene terephthalate waste, pose an environmental challenge. In this review, we highlight the uniqueness of aromatic carboxylesters and then underscore the importance of relevant carboxylesterases.
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Affiliation(s)
- Venkatesh M Ghodke
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
| | - Narayan S Punekar
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
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