1
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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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Kim DW, Lim ES, Lee GH, Son HF, Sung C, Jung JH, Park HJ, Gong G, Ko JK, Um Y, Han SO, Ahn JH. Biodegradation of oxidized low density polyethylene by Pelosinus fermentans lipase. BIORESOURCE TECHNOLOGY 2024; 403:130871. [PMID: 38782190 DOI: 10.1016/j.biortech.2024.130871] [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: 03/13/2024] [Revised: 04/28/2024] [Accepted: 05/20/2024] [Indexed: 05/25/2024]
Abstract
Polyethylene (PE) exhibits high resistance to degradation, contributing to plastic pollution. PE discarded into the environment is photo-oxidized by sunlight and oxygen. In this study, a key enzyme capable of degrading oxidized PE is reported for the first time. Twenty different enzymes from various lipase families were evaluated for hydrolytic activity using substrates mimicking oxidized PE. Among them, Pelosinus fermentans lipase 1 (PFL1) specifically cleaved the ester bonds within the oxidized carbon-carbon backbone. Moreover, PFL1 (6 μM) degraded oxidized PE film, reducing the weight average and number average molecular weights by 44.6 and 11.3 %, respectively, within five days. Finally, structural analysis and molecular docking simulations were performed to elucidate the degradation mechanism of PFL1. The oxidized PE-degrading enzyme reported here will provide the groundwork for advancing PE waste treatment technology and for engineering microbes to repurpose PE waste into valuable chemicals.
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Affiliation(s)
- Do-Wook Kim
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
| | - Eui Seok Lim
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea; Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Ga Hyun Lee
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea; Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Hyeoncheol Francis Son
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
| | - Changmin Sung
- Doping Control Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea
| | - Jong-Hyun Jung
- Radiation Biotechnology Division, Korea Atomic Energy Research Institute, Jeongeup 56212, Republic of Korea
| | - Hyun June Park
- Department of Biotechnology, Duksung Women's University, Seoul 01369, Republic of Korea
| | - Gyeongtaek Gong
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea; Division of Energy and Environment Technology, KIST School, University of Science and Technology (UST), Daejeon 34113, Republic of Korea
| | - Ja Kyong Ko
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea; Division of Energy and Environment Technology, KIST School, University of Science and Technology (UST), Daejeon 34113, Republic of Korea
| | - Youngsoon Um
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea; Division of Energy and Environment Technology, KIST School, University of Science and Technology (UST), Daejeon 34113, Republic of Korea
| | - Sung Ok Han
- Department of Biotechnology, Korea University, Seoul 02841, Republic of Korea
| | - Jung Ho Ahn
- Clean Energy Research Center, Korea Institute of Science and Technology, Seoul 02792, Republic of Korea; Division of Energy and Environment Technology, KIST School, University of Science and Technology (UST), Daejeon 34113, Republic of Korea.
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3
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Aer L, Jiang Q, Zhong L, Si Q, Liu X, Pan Y, Feng J, Zeng H, Tang L. Optimization of polyethylene terephthalate biodegradation using a self-assembled multi-enzyme cascade strategy. JOURNAL OF HAZARDOUS MATERIALS 2024; 476:134887. [PMID: 38901251 DOI: 10.1016/j.jhazmat.2024.134887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2024] [Revised: 06/04/2024] [Accepted: 06/10/2024] [Indexed: 06/22/2024]
Abstract
Although many efforts have been devoted to the modification of polyethylene terephthalate (PET) hydrolases for improving the efficiency of PET degradation, the catalytic performance of these enzymes at near-ambient temperatures remains a challenge. Herein, a multi-enzyme cascade system (PT-EC) was developed and validated by assembling three well-developed PETases, PETaseEHA, Fast-PETase, and Z1-PETase, respectively, together with carboxylesterase TfCa, and hydrophobic binding module CBM3a using scaffold proteins. The resulting PT-ECEHA, PT-ECFPE, PT-ECZPE all demonstrated outstanding PET degradation efficacy. Notably, PT-ECEHA exhibited a 16.5-fold increase in product release compared to PETaseEHA, and PT-ECZPE yielded the highest amount of product. Subsequently, PT-ECs were displayed on the surface of Escherichia coli, respectively, and their degradation efficiency toward three PET types was investigated. The displayed PT-ECEHA exhibited a 20-fold increase in degradation efficiency with PET film compared to the surface-displayed PETaseEHA. Remarkably, an almost linear increase in product release was observed for the displayed PT-ECZPE over a one-week degradation period, reaching 11.56 ± 0.64 mM after 7 days. TfCaI69W/L281Y evolved using a docking-based virtual screening strategy showed a further 2.5-fold increase in the product release of PET degradation. Collectively, these advantages of PT-EC demonstrated the potential of a multi-enzyme cascade system for PET bio-cycling.
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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
| | - Linling Zhong
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Qiuyue Si
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Xianghong Liu
- School of Life Science and Technology, University of Electronic Science and Technology of China, Chengdu 610054, China
| | - Yan Pan
- Medical School of 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
| | - Hongjuan Zeng
- 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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4
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Zhang X, Zhang X, Shi H, Zhang H, Zhang J, Yue C, Li D, Yao L, Tang C. Combining Flexible Region Design and Automatic Design to Enhance the Thermal Stability and Catalytic Efficiency of Leucine Dehydrogenase. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024. [PMID: 38838197 DOI: 10.1021/acs.jafc.4c02152] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2024]
Abstract
Leucine dehydrogenase (LeuDH, EC 1.4.1.9) can reversibly catalyze the oxidative deamination of l-leucine and some other specific α-amino acids to form the corresponding α-ketoacids. This reaction has great significance in the field of food additives and the pharmaceutical industry. The LeuDH from Exiguobacterium sibiricum (EsLeuDH) has high catalytic efficiency but limited thermal stability, hindering its widespread industrial application. In this study, a mutant N5F/I12L/A352Y of EsLeuDH (referred to as M2) was developed with enhanced thermal stability and catalytic activity through rational modification. The M2 mutant exhibits a half-life at 60 °C (t1/2(60 °C)) of 975.7 min and a specific activity of 69.6 U mg-1, which is 5.4 and 2.1 times higher than those of EsLeuDH, respectively. This research may facilitate the utilization of EsLeuDH at elevated temperatures, enhancing its potential for industrial applications. The findings offer a practical and efficient approach for optimizing LeuDH and other industrial enzymes.
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Affiliation(s)
- Xiang Zhang
- College of Life Science, Nanyang Normal University, 1638 Wolong Road, Nanyang, Henan 473061, People's Republic of China
| | - Xichuan Zhang
- College of Life Science, Nanyang Normal University, 1638 Wolong Road, Nanyang, Henan 473061, People's Republic of China
| | - Hongling Shi
- College of Life Science, Nanyang Normal University, 1638 Wolong Road, Nanyang, Henan 473061, People's Republic of China
| | - Huimin Zhang
- College of Animal Science and Technology, Yangzhou University, 88 South Daxue Road, Yangzhou, Jiangsu 225009, People's Republic of China
| | - Jianhui Zhang
- Postdoctoral Innovation Training Base, She Dian Lao Jiu Co. Ltd., 2 Liquor Avenue, Nanyang, Henan 473300, People's Republic of China
| | - Chao Yue
- College of Life Science, Nanyang Normal University, 1638 Wolong Road, Nanyang, Henan 473061, People's Republic of China
| | - Dandan Li
- College of Life Science, Nanyang Normal University, 1638 Wolong Road, Nanyang, Henan 473061, People's Republic of China
| | - Lunguang Yao
- College of Life Science, Nanyang Normal University, 1638 Wolong Road, Nanyang, Henan 473061, People's Republic of China
| | - Cunduo Tang
- College of Life Science, Nanyang Normal University, 1638 Wolong Road, Nanyang, Henan 473061, People's Republic of China
- Postdoctoral Innovation Training Base, She Dian Lao Jiu Co. Ltd., 2 Liquor Avenue, Nanyang, Henan 473300, People's Republic of China
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5
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Zheng Y, Zhang J, You S, Lin W, Su R, Qi W. Efficient thermophilic polyethylene terephthalate hydrolase enhanced by cross correlation-based accumulated mutagenesis strategy. BIORESOURCE TECHNOLOGY 2024; 406:130929. [PMID: 38838832 DOI: 10.1016/j.biortech.2024.130929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 05/22/2024] [Accepted: 06/02/2024] [Indexed: 06/07/2024]
Abstract
Polyethylene terephthalate (PET) has caused significant pollution issues. Compared to chemical degradation with high energy consumption and cost, enzymatic degradation offers a sustainable solution for PET waste recycling. However, the hydrolytic activity of current PET hydrolases still requires improvement. In this study, a cross-correlation-based accumulated mutagenesis (CAM) strategy was developed to enhance the hydrolysis activity. By mitigating epistatic effect and combinational mutations, we achieved a highly active variant LCC-YGA (H183Y/L124G/S29A) with 2.1-fold hydrolytic activity on amorphous PET films of LCC-ICCG. Conformational analysis elucidated how the introduction of distal mutations enhanced activity. The dynamic correlation among different regions facilitated a synergistic effect, enhancing binding pocket flexibility through remote interactions. Totally, this work offers novel insights and methods for PET hydrolases engineering and provides an efficient enzyme for PET degradation and recycling.
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Affiliation(s)
- Yunxin Zheng
- State Key Laboratory of Chemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China
| | - Jiaxing Zhang
- State Key Laboratory of Chemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China
| | - Shengping You
- State Key Laboratory of Chemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China
| | - Wei Lin
- State Key Laboratory of Chemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China
| | - Rongxin Su
- State Key Laboratory of Chemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China; Collaborative Innovation Centre 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
| | - Wei Qi
- State Key Laboratory of Chemical Engineering, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China; Collaborative Innovation Centre 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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6
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Qi X, Wu Y, Zhang ST, Yin CF, Ji M, Liu Y, Xu Y, Zhou NY. The unique salt bridge network in GlacPETase: a key to its stability. Appl Environ Microbiol 2024; 90:e0224223. [PMID: 38358247 PMCID: PMC10952487 DOI: 10.1128/aem.02242-23] [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: 12/12/2023] [Accepted: 01/25/2024] [Indexed: 02/16/2024] Open
Abstract
The extensive accumulation of polyethylene terephthalate (PET) has become a critical environmental issue. PET hydrolases can break down PET into its building blocks. Recently, we identified a glacial PET hydrolase GlacPETase sharing less than 31% amino acid identity with any known PET hydrolases. In this study, the crystal structure of GlacPETase was determined at 1.8 Å resolution, revealing unique structural features including a distinctive N-terminal disulfide bond and a specific salt bridge network. Site-directed mutagenesis demonstrated that the disruption of the N-terminal disulfide bond did not reduce GlacPETase's thermostability or its catalytic activity on PET. However, mutations in the salt bridges resulted in changes in melting temperature ranging from -8°C to +2°C and the activity on PET ranging from 17.5% to 145.5% compared to the wild type. Molecular dynamics simulations revealed that these salt bridges stabilized the GlacPETase's structure by maintaining their surrounding structure. Phylogenetic analysis indicated that GlacPETase represented a distinct branch within PET hydrolases-like proteins, with the salt bridges and disulfide bonds in this branch being relatively conserved. This research contributed to the improvement of our comprehension of the structural mechanisms that dictate the thermostability of PET hydrolases, highlighting the diverse characteristics and adaptability observed within PET hydrolases.IMPORTANCEThe pervasive problem of polyethylene terephthalate (PET) pollution in various terrestrial and marine environments is widely acknowledged and continues to escalate. PET hydrolases, such as GlacPETase in this study, offered a solution for breaking down PET. Its unique origin and less than 31% identity with any known PET hydrolases have driven us to resolve its structure. Here, we report the correlation between its unique structure and biochemical properties, focusing on an N-terminal disulfide bond and specific salt bridges. Through site-directed mutagenesis experiments and molecular dynamics simulations, the roles of the N-terminal disulfide bond and salt bridges were elucidated in GlacPETase. This research enhanced our understanding of the role of salt bridges in the thermostability of PET hydrolases, providing a valuable reference for the future engineering of PET hydrolases.
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Affiliation(s)
- Xiaoyan Qi
- 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, China
| | - Yanfei Wu
- 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, China
| | - Shu-Ting Zhang
- 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, China
| | - Chao-Fan Yin
- 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, China
| | - Mukan Ji
- Center for Pan-third Pole Environment, Lanzhou University, Lanzhou, China
| | - Yongqin Liu
- Center for Pan-third Pole Environment, Lanzhou University, Lanzhou, China
| | - Ying Xu
- 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, 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, China
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7
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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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8
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Zhang J, Wang H, Luo Z, Yang Z, Zhang Z, Wang P, Li M, Zhang Y, Feng Y, Lu D, Zhu Y. Computational design of highly efficient thermostable MHET hydrolases and dual enzyme system for PET recycling. Commun Biol 2023; 6:1135. [PMID: 37945666 PMCID: PMC10636135 DOI: 10.1038/s42003-023-05523-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Accepted: 10/30/2023] [Indexed: 11/12/2023] Open
Abstract
Recently developed enzymes for the depolymerization of polyethylene terephthalate (PET) such as FAST-PETase and LCC-ICCG are inhibited by the intermediate PET product mono(2-hydroxyethyl) terephthalate (MHET). Consequently, the conversion of PET enzymatically into its constituent monomers terephthalic acid (TPA) and ethylene glycol (EG) is inefficient. In this study, a protein scaffold (1TQH) corresponding to a thermophilic carboxylesterase (Est30) was selected from the structural database and redesigned in silico. Among designs, a double variant KL-MHETase (I171K/G130L) with a similar protein melting temperature (67.58 °C) to that of the PET hydrolase FAST-PETase (67.80 °C) exhibited a 67-fold higher activity for MHET hydrolysis than FAST-PETase. A fused dual enzyme system comprising KL-MHETase and FAST-PETase exhibited a 2.6-fold faster PET depolymerization rate than FAST-PETase alone. Synergy increased the yield of TPA by 1.64 fold, and its purity in the released aromatic products reached 99.5%. In large reaction systems with 100 g/L substrate concentrations, the dual enzyme system KL36F achieved over 90% PET depolymerization into monomers, demonstrating its potential applicability in the industrial recycling of PET plastics. Therefore, a dual enzyme system can greatly reduce the reaction and separation cost for sustainable enzymatic PET recycling.
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Affiliation(s)
- Jun Zhang
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, China
- Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China
| | - Hongzhao Wang
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Zhaorong Luo
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Zhenwu Yang
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Zixuan Zhang
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Pengyu Wang
- Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China
| | - Mengyu Li
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Yi Zhang
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Yue Feng
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing, 100029, China
| | - Diannan Lu
- Department of Chemical Engineering, Tsinghua University, Beijing, 100084, China.
| | - Yushan Zhu
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, China.
- National Energy R&D Center for Biorefinery, Beijing University of Chemical Technology, Beijing, 100029, China.
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9
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Qu Z, Chen K, Zhang L, Sun Y. Computation-Based Design of Salt Bridges in PETase for Enhanced Thermostability and Performance for PET Degradation. Chembiochem 2023; 24:e202300373. [PMID: 37639367 DOI: 10.1002/cbic.202300373] [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: 05/19/2023] [Revised: 08/28/2023] [Accepted: 08/28/2023] [Indexed: 08/31/2023]
Abstract
Polyethylene terephthalate (PET) is one of the most widely used plastics, and the accumulation of PET poses a great threat to the environment. IsPETase can degrade PET rapidly at moderate temperatures, but its application is greatly limited by the low stability. Herein, molecular dynamics (MD) simulations combined with a sequence alignment strategy were adopted to introduce salt bridges into the flexible region of IsPETase to improve its thermal stability. In the designed variants, the Tm values of IsPETaseI168R/S188D and IsPETaseI168R/S188E were 7.4 and 8.7 °C higher than that of the wild type, respectively. The release of products degraded by IsPETaseI168R/S188E was 4.3 times that of the wild type. Tertiary structure characterization demonstrated that the structure of the variants IsPETaseI168R/S188D and IsPETaseI168R/S188E became more compact. Extensive MD simulations verified that a stable salt bridge was formed between the residue R168 and D186 in IsPETaseI168R/S188D , while in IsPETaseI168R/S188E an R168-D186-E188 salt bridge network was observed. These results confirmed that the proposed computation-based salt bridge design strategy could efficiently generate variants with enhanced thermal stability for the long-term degradation of PET, which would be helpful for the design of enzymes with improved stability.
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Affiliation(s)
- Zhi Qu
- Department of Biochemical Engineering, School of Chemical Engineering and Technology and, Key Laboratory of Systems Bioengineering and, Frontiers Science Center for Synthetic Biology (Ministry of Education), Tianjin University, Tianjin, 300350, China
| | - Kun Chen
- Department of Biochemical Engineering, School of Chemical Engineering and Technology and, Key Laboratory of Systems Bioengineering and, Frontiers Science Center for Synthetic Biology (Ministry of Education), Tianjin University, Tianjin, 300350, China
| | - Lin Zhang
- Department of Biochemical Engineering, School of Chemical Engineering and Technology and, Key Laboratory of Systems Bioengineering and, Frontiers Science Center for Synthetic Biology (Ministry of Education), Tianjin University, Tianjin, 300350, China
| | - Yan Sun
- Department of Biochemical Engineering, School of Chemical Engineering and Technology and, Key Laboratory of Systems Bioengineering and, Frontiers Science Center for Synthetic Biology (Ministry of Education), Tianjin University, Tianjin, 300350, China
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10
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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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11
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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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12
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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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13
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Son J, Lim SH, Kim YJ, Lim HJ, Lee JY, Jeong S, Park C, Park SJ. Customized valorization of waste streams by Pseudomonas putida: State-of-the-art, challenges, and future trends. BIORESOURCE TECHNOLOGY 2023; 371:128607. [PMID: 36638894 DOI: 10.1016/j.biortech.2023.128607] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/07/2023] [Accepted: 01/09/2023] [Indexed: 06/17/2023]
Abstract
Preventing catastrophic climate events warrants prompt action to delay global warming, which threatens health and food security. In this context, waste management using engineered microbes has emerged as a long-term eco-friendly solution for addressing the global climate crisis and transitioning to clean energy. Notably, Pseudomonas putida can valorize industry-derived synthetic wastes including plastics, oils, food, and agricultural waste into products of interest, and it has been extensively explored for establishing a fully circular bioeconomy through the conversion of waste into bio-based products, including platform chemicals (e.g., cis,cis-muconic and adipic acid) and biopolymers (e.g., medium-chain length polyhydroxyalkanoate). However, the efficiency of waste pretreatment technologies, capability of microbial cell factories, and practicability of synthetic biology tools remain low, posing a challenge to the industrial application of P. putida. The present review discusses the state-of-the-art, challenges, and future prospects for divergent biosynthesis of versatile products from waste-derived feedstocks using P. putida.
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Affiliation(s)
- Jina Son
- Department of Chemical Engineering and Materials Science, Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Seo Hyun Lim
- Department of Chemical Engineering and Materials Science, Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Yu Jin Kim
- Department of Chemical Engineering and Materials Science, Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Hye Jin Lim
- Department of Chemical Engineering and Materials Science, Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Ji Yeon Lee
- Department of Chemical Engineering and Materials Science, Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Seona Jeong
- Department of Chemical Engineering and Materials Science, Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Chulhwan Park
- Department of Chemical Engineering, Kwangwoon University, Seoul 01897, Republic of Korea
| | - Si Jae Park
- Department of Chemical Engineering and Materials Science, Graduate Program in System Health Science and Engineering, Ewha Womans University, Seoul 03760, Republic of Korea.
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