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Wang T, Yang WT, Gong YM, Zhang YK, Fan XX, Wang GC, Lu ZH, Liu F, Liu XH, Zhu YS. Molecular engineering of PETase for efficient PET biodegradation. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2024; 280:116540. [PMID: 38833982 DOI: 10.1016/j.ecoenv.2024.116540] [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: 02/23/2024] [Revised: 05/29/2024] [Accepted: 05/31/2024] [Indexed: 06/06/2024]
Abstract
The widespread utilization of polyethylene terephthalate (PET) has caused a variety of environmental and health problems. Compared with traditional thermomechanical or chemical PET cycling, the biodegradation of PET may offer a more feasible solution. Though the PETase from Ideonalla sakaiensis (IsPETase) displays interesting PET degrading performance under mild conditions; the relatively low thermal stability of IsPETase limits its practical application. In this study, enzyme-catalysed PET degradation was investigated with the promising IsPETase mutant HotPETase (HP). On this basis, a carbohydrate-binding module from Bacillus anthracis (BaCBM) was fused to the C-terminus of HP to construct the PETase mutant (HLCB) for increased PET degradation. Furthermore, to effectively improve PET accessibility and PET-degrading activity, the truncated outer membrane hybrid protein (FadL) was used to expose PETase and BaCBM on the surface of E. coli (BL21with) to develop regenerable whole-cell biocatalysts (D-HLCB). Results showed that, among the tested small-molecular weight ester compounds (p-nitrophenyl phosphate (pNPP), p-Nitrophenyl acetate (pNPA), 4-Nitrophenyl butyrate (pNPB)), PETase displayed the highest hydrolysing activity against pNPP. HP displayed the highest catalytic activity (1.94 μM(p-NP)/min) at 50 °C and increased longevity at 40 °C. The fused BaCBM could clearly improve the catalytic performance of PETase by increasing the optimal reaction temperature and improving the thermostability. When HLCB was used for PET degradation, the yield of monomeric products (255.7 μM) was ∼25.5 % greater than that obtained after 50 h of HP-catalysed PET degradation. Moreover, the highest yield of monomeric products from the D-HLCB-mediated system reached 1.03 mM. The whole-cell catalyst D-HLCB displayed good reusability and stability and could maintain more than 54.6 % of its initial activity for nine cycles. Finally, molecular docking simulations were utilized to investigate the binding mechanism and the reaction mechanism of HLCB, which may provide theoretical evidence to further increase the PET-degrading activities of PETases through rational design. The proposed strategy and developed variants show potential for achieving complete biodegradation of PET under mild conditions.
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Affiliation(s)
- Tao Wang
- School of Biological Science, Jining Medical University, Jining, China
| | - Wen-Tao Yang
- School of Biological Science, Jining Medical University, Jining, China
| | - Yu-Ming Gong
- School of Biological Science, Jining Medical University, Jining, China
| | - Ying-Kang Zhang
- School of Biological Science, Jining Medical University, Jining, China
| | - Xin-Xin Fan
- School of Biological Science, Jining Medical University, Jining, China
| | - Guo-Cheng Wang
- School of Biological Science, Jining Medical University, Jining, China
| | - Zhen-Hua Lu
- College of Chemical and Biological Engineering, Zhejiang University, Hangzhou 310027, China
| | - Fei Liu
- School of Biological Science, Jining Medical University, Jining, China
| | - Xiao-Huan Liu
- School of Biological Science, Jining Medical University, Jining, China
| | - You-Shuang Zhu
- School of Biological Science, Jining Medical University, Jining, China.
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2
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Schreiber S, Gercke D, Lenz F, Jose J. Application of an alchemical free energy method for the prediction of thermostable DuraPETase variants. Appl Microbiol Biotechnol 2024; 108:305. [PMID: 38643427 PMCID: PMC11033240 DOI: 10.1007/s00253-024-13144-z] [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: 01/16/2024] [Revised: 03/25/2024] [Accepted: 04/09/2024] [Indexed: 04/22/2024]
Abstract
Non-equilibrium (NEQ) alchemical free energy calculations are an emerging tool for accurately predicting changes in protein folding free energy resulting from amino acid mutations. In this study, this method in combination with the Rosetta ddg monomer tool was applied to predict more thermostable variants of the polyethylene terephthalate (PET) degrading enzyme DuraPETase. The Rosetta ddg monomer tool efficiently enriched promising mutations prior to more accurate prediction by NEQ alchemical free energy calculations. The relative change in folding free energy of 96 single amino acid mutations was calculated by NEQ alchemical free energy calculation. Experimental validation of ten of the highest scoring variants identified two mutations (DuraPETaseS61M and DuraPETaseS223Y) that increased the melting temperature (Tm) of the enzyme by up to 1 °C. The calculated relative change in folding free energy showed an excellent correlation with experimentally determined Tm resulting in a Pearson's correlation coefficient of r = - 0.84. Limitations in the prediction of strongly stabilizing mutations were, however, encountered and are discussed. Despite these challenges, this study demonstrates the practical applicability of NEQ alchemical free energy calculations in prospective enzyme engineering projects. KEY POINTS: • Rosetta ddg monomer enriches stabilizing mutations in a library of DuraPETase variants • NEQ free energy calculations accurately predict changes in Tm of DuraPETase • The DuraPETase variants S223Y, S42M, and S61M have increased Tm.
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Affiliation(s)
- Sebastian Schreiber
- University of Münster, Institute of Pharmaceutical and Medicinal Chemistry, PharmaCampus, Corrensstr. 48, 48149, Münster, Germany
| | - David Gercke
- University of Münster, Institute of Pharmaceutical and Medicinal Chemistry, PharmaCampus, Corrensstr. 48, 48149, Münster, Germany
| | - Florian Lenz
- University of Münster, Institute of Pharmaceutical and Medicinal Chemistry, PharmaCampus, Corrensstr. 48, 48149, Münster, Germany
| | - Joachim Jose
- University of Münster, Institute of Pharmaceutical and Medicinal Chemistry, PharmaCampus, Corrensstr. 48, 48149, Münster, Germany.
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3
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Taxeidis G, Djapovic M, Nikolaivits E, Maslak V, Nikodinovic-Runic J, Topakas E. New Labeled PET Analogues Enable the Functional Screening and Characterization of PET-Degrading Enzymes. ACS SUSTAINABLE CHEMISTRY & ENGINEERING 2024; 12:5943-5952. [PMID: 38903150 PMCID: PMC11187625 DOI: 10.1021/acssuschemeng.4c00143] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 03/14/2024] [Accepted: 03/15/2024] [Indexed: 06/22/2024]
Abstract
The discovery and engineering of novel biocatalysts capable of depolymerizing polyethylene terephthalate (PET) have gained significant attention since the need for green technologies to combat plastic pollution has become increasingly urgent. This study focuses on the development of novel substrates that can indicate enzymes with PET hydrolytic activity, streamlining the process of enzyme evaluation and selection. Four novel substrates, mimicking the structure of PET, were chemically synthesized and labeled with fluorogenic or chromogenic moieties, enabling the direct analysis of candidate enzymes without complex preparatory or analysis steps. The fluorogenic substrates, mUPET1, mUPET2, and mUPET3, not only identify enzymes capable of PET breakdown but also differentiate those with exceptional performance on the polymer, such as the benchmark PETase, LCCICCG. Among the substrates, the chromogenic p-NPhPET3 stands out as a reliable tool for screening both pure and crude enzymes, offering advantages over fluorogenic substrates such as ease of assay using UV-vis spectroscopy and compatibility with crude enzyme samples. However, ferulic acid esterases and mono-(2-hydroxyethyl) terephthalate esterases (MHETases), which exhibit remarkably high affinity for PET oligomers, also show high catalytic activity on these substrates. The substrates introduced in this study hold significant value in the function-based screening and characterization of enzymes that degrade PET, as well as the the potential to be used in screening mutant libraries derived from directed evolution experiments. Following this approach, a rapid and dependable assay method can be carried out using basic laboratory infrastructure, eliminating the necessity for intricate preparatory procedures before analysis.
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Affiliation(s)
- George Taxeidis
- Industrial
Biotechnology & Biocatalysis Group, Biotechnology Laboratory,
School of Chemical Engineering, National
Technical University of Athens, Heroon Polytechniou 9, Zografou, 15772 Athens, Greece
| | - Milica Djapovic
- Faculty
of Chemistry, University of Belgrade, Studentski trg 12-16, 11000 Belgrade, Belgrade, Serbia
| | - Efstratios Nikolaivits
- Industrial
Biotechnology & Biocatalysis Group, Biotechnology Laboratory,
School of Chemical Engineering, National
Technical University of Athens, Heroon Polytechniou 9, Zografou, 15772 Athens, Greece
| | - Veselin Maslak
- Faculty
of Chemistry, University of Belgrade, Studentski trg 12-16, 11000 Belgrade, Belgrade, Serbia
| | - Jasmina Nikodinovic-Runic
- Institute
of Molecular Genetics and Genetic Engineering, University of Belgrade, Vojvode Stepe 444a, 11000 Belgrade, Serbia
| | - Evangelos Topakas
- Industrial
Biotechnology & Biocatalysis Group, Biotechnology Laboratory,
School of Chemical Engineering, National
Technical University of Athens, Heroon Polytechniou 9, Zografou, 15772 Athens, Greece
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4
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Joho Y, Vongsouthi V, Gomez C, Larsen JS, Ardevol A, Jackson CJ. Improving plastic degrading enzymes via directed evolution. Protein Eng Des Sel 2024; 37:gzae009. [PMID: 38713696 PMCID: PMC11091475 DOI: 10.1093/protein/gzae009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2023] [Revised: 04/30/2024] [Accepted: 05/05/2024] [Indexed: 05/09/2024] Open
Abstract
Plastic degrading enzymes have immense potential for use in industrial applications. Protein engineering efforts over the last decade have resulted in considerable enhancement of many properties of these enzymes. Directed evolution, a protein engineering approach that mimics the natural process of evolution in a laboratory, has been particularly useful in overcoming some of the challenges of structure-based protein engineering. For example, directed evolution has been used to improve the catalytic activity and thermostability of polyethylene terephthalate (PET)-degrading enzymes, although its use for the improvement of other desirable properties, such as solvent tolerance, has been less studied. In this review, we aim to identify some of the knowledge gaps and current challenges, and highlight recent studies related to the directed evolution of plastic-degrading enzymes.
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Affiliation(s)
- Yvonne Joho
- Manufacturing, Commonwealth Scientific and Industrial Research Organisation, Research Way, Clayton, Victoria 3168, Australia
- Research School of Chemistry, Australian National University, Sullivans Creek Rd, Canberra, ACT 2601, Australia
- CSIRO Advanced Engineering Biology Future Science Platform, GPO Box 1700, Canberra, ACT 2601, Australia
| | - Vanessa Vongsouthi
- Research School of Chemistry, Australian National University, Sullivans Creek Rd, Canberra, ACT 2601, Australia
| | - Chloe Gomez
- Research School of Chemistry, Australian National University, Sullivans Creek Rd, Canberra, ACT 2601, Australia
| | - Joachim S Larsen
- Research School of Chemistry, Australian National University, Sullivans Creek Rd, Canberra, ACT 2601, Australia
- ARC Centre of Excellence for Synthetic Biology, Research School of Chemistry, Australian National University, Sullivans Creek Rd, Canberra, ACT 2601, Australia
| | - Albert Ardevol
- Manufacturing, Commonwealth Scientific and Industrial Research Organisation, Research Way, Clayton, Victoria 3168, Australia
- CSIRO Advanced Engineering Biology Future Science Platform, GPO Box 1700, Canberra, ACT 2601, Australia
| | - Colin J Jackson
- Research School of Chemistry, Australian National University, Sullivans Creek Rd, Canberra, ACT 2601, Australia
- ARC Centre of Excellence for Synthetic Biology, Research School of Chemistry, Australian National University, Sullivans Creek Rd, Canberra, ACT 2601, Australia
- ARC Centre of Excellence for Innovations in Peptide & Protein Science, Research School of Chemistry, Australian National University, Sullivans Creek Rd, Canberra, ACT 2601, Australia
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5
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Shi L, Zhu L. Recent Advances and Challenges in Enzymatic Depolymerization and Recycling of PET Wastes. Chembiochem 2024; 25:e202300578. [PMID: 37960968 DOI: 10.1002/cbic.202300578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Revised: 11/12/2023] [Accepted: 11/13/2023] [Indexed: 11/15/2023]
Abstract
Poly (ethylene terephthalate) (PET) is one of the most commonly used plastics in daily life and various industries. Enzymatic depolymerization and recycling of post-consumer PET (pc-PET) provides a promising strategy for the sustainable circular economy of polymers. Great protein engineering efforts have been devoted to improving the depolymerization performance of PET hydrolytic enzymes (PHEs). In this review, we first discuss the mechanisms and challenges of enzymatic PET depolymerization. Subsequently, we summarize the state-of-the-art engineering of PHEs including rational design, machine learning, and directed evolution for improved depolymerization performance, and highlight the advances in screening methods of PHEs. We further discuss several factors that affect the enzymatic depolymerization efficiency. We conclude with our perspective on the opportunities and challenges in bio-recycling and bio-upcycling of PET wastes.
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Affiliation(s)
- Lixia Shi
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, China
- National Technology Innovation Center of Synthetic Biology, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, China
| | - Leilei Zhu
- Key Laboratory of Engineering Biology for Low-Carbon Manufacturing, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, China
- National Technology Innovation Center of Synthetic Biology, 32 West 7th Avenue, Tianjin Airport Economic Area, Tianjin, 300308, China
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6
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Sana B, Ding K, Siau JW, Pasula RR, Chee S, Kharel S, Lena JBH, Goh E, Rajamani L, Lam YM, Lim S, Ghadessy JF. Thermostability enhancement of polyethylene terephthalate degrading PETase using self- and nonself-ligating protein scaffolding approaches. Biotechnol Bioeng 2023; 120:3200-3209. [PMID: 37555384 DOI: 10.1002/bit.28523] [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: 06/05/2023] [Revised: 07/17/2023] [Accepted: 07/23/2023] [Indexed: 08/10/2023]
Abstract
Polyethylene terephthalate (PET) hydrolase enzymes show promise for enzymatic PET degradation and green recycling of single-use PET vessels representing a major source of global pollution. Their full potential can be unlocked with enzyme engineering to render activities on recalcitrant PET substrates commensurate with cost-effective recycling at scale. Thermostability is a highly desirable property in industrial enzymes, often imparting increased robustness and significantly reducing quantities required. To date, most engineered PET hydrolases show improved thermostability over their parental enzymes. Here, we report engineered thermostable variants of Ideonella sakaiensis PET hydrolase enzyme (IsPETase) developed using two scaffolding strategies. The first employed SpyCatcher-SpyTag technology to covalently cyclize IsPETase, resulting in increased thermostability that was concomitant with reduced turnover of PET substrates compared to native IsPETase. The second approach using a GFP-nanobody fusion protein (vGFP) as a scaffold yielded a construct with a melting temperature of 80°C. This was further increased to 85°C when a thermostable PETase variant (FAST PETase) was scaffolded into vGFP, the highest reported so far for an engineered PET hydrolase derived from IsPETase. Thermostability enhancement using the vGFP scaffold did not compromise activity on PET compared to IsPETase. These contrasting results highlight potential topological and dynamic constraints imposed by scaffold choice as determinants of enzyme activity.
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Affiliation(s)
- Barindra Sana
- Disease Intervention Technology Laboratory, Institute of Molecular and Cell Biology, Agency for Science Technology and Research, Singapore, Singapore
| | - Ke Ding
- Disease Intervention Technology Laboratory, Institute of Molecular and Cell Biology, Agency for Science Technology and Research, Singapore, Singapore
| | - Jia Wei Siau
- Disease Intervention Technology Laboratory, Institute of Molecular and Cell Biology, Agency for Science Technology and Research, Singapore, Singapore
| | - Rupali Reddy Pasula
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological Univeristy, Singapore, Singapore
| | - Sharon Chee
- Disease Intervention Technology Laboratory, Institute of Molecular and Cell Biology, Agency for Science Technology and Research, Singapore, Singapore
| | - Sharad Kharel
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore
| | - Jean-Baptise Henri Lena
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore
| | - Eunice Goh
- Singapore Eye Research Institute, The Academia, Singapore, Singapore
| | | | - Yeng Ming Lam
- School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore
| | - Sierin Lim
- School of Chemistry, Chemical Engineering and Biotechnology, Nanyang Technological Univeristy, Singapore, Singapore
| | - John F Ghadessy
- Disease Intervention Technology Laboratory, Institute of Molecular and Cell Biology, Agency for Science Technology and Research, Singapore, Singapore
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7
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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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8
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Holst LH, Madsen NG, Toftgård FT, Rønne F, Moise IM, Petersen EI, Fojan P. De novo design of a polycarbonate hydrolase. Protein Eng Des Sel 2023; 36:gzad022. [PMID: 38035789 DOI: 10.1093/protein/gzad022] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 10/31/2023] [Accepted: 11/14/2023] [Indexed: 12/02/2023] Open
Abstract
Enzymatic degradation of plastics is currently limited to the use of engineered natural enzymes. As of yet, all engineering approaches applied to plastic degrading enzymes retain the natural $\alpha /\beta $-fold. While mutations can be used to increase thermostability, an inherent maximum likely exists for the $\alpha /\beta $-fold. It is thus of interest to introduce catalytic activity toward plastics in a different protein fold to escape the sequence space of plastic degrading enzymes. Here, a method for designing highly thermostable enzymes that can degrade plastics is described. With the help of Rosetta an active site catalysing the hydrolysis of polycarbonate is introduced into a set of thermostable scaffolds. Through computational evaluation, a potential PCase was selected and produced recombinantly in Escherichia coli. Thermal analysis suggests that the design has a melting temperature of >95$^{\circ }$C. Activity toward polycarbonate was confirmed using atomic force spectroscopy (AFM), proving the successful design of a PCase.
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Affiliation(s)
- Laura H Holst
- Material Science and Engineering Group, Department of Materials and Production, Aalborg University, 9000 Aalborg, Denmark
| | - Niklas G Madsen
- Material Science and Engineering Group, Department of Materials and Production, Aalborg University, 9000 Aalborg, Denmark
| | - Freja T Toftgård
- Material Science and Engineering Group, Department of Materials and Production, Aalborg University, 9000 Aalborg, Denmark
| | - Freja Rønne
- Material Science and Engineering Group, Department of Materials and Production, Aalborg University, 9000 Aalborg, Denmark
| | - Ioana-Malina Moise
- Material Science and Engineering Group, Department of Materials and Production, Aalborg University, 9000 Aalborg, Denmark
| | - Evamaria I Petersen
- Material Science and Engineering Group, Department of Materials and Production, Aalborg University, 9000 Aalborg, Denmark
| | - Peter Fojan
- Material Science and Engineering Group, Department of Materials and Production, Aalborg University, 9000 Aalborg, Denmark
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