1
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Dahiya D, Koitto T, Kutvonen K, Wang Y, Haddad Momeni M, de Ruijter S, Master ER. Fungal loosenin-like proteins boost the cellulolytic enzyme conversion of pretreated wood fiber and cellulosic pulps. BIORESOURCE TECHNOLOGY 2024; 394:130188. [PMID: 38104665 DOI: 10.1016/j.biortech.2023.130188] [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: 11/03/2023] [Revised: 12/06/2023] [Accepted: 12/07/2023] [Indexed: 12/19/2023]
Abstract
Microbial expansin-related proteins, including loosenins, can disrupt cellulose networks and increase enzyme accessibility to cellulosic substrates. Herein, four loosenins from Phanerochaete carnosa (PcaLOOLs), and a PcaLOOL fused to a family 63 carbohydrate-binding module, were compared for ability to boost the cellulolytic deconstruction of steam pretreated softwood (SSW) and kraft pulps from softwood (ND-BSKP) and hardwood (ND-BHKP). Amending the Cellic® CTec-2 cellulase cocktail with PcaLOOLs increased reducing products from SSW by up to 40 %, corresponding to 28 % higher glucose yield. Amending Cellic® CTec-2 with PcaLOOLs also increased the release of glucose from ND-BSKP and ND-BHKP by 82 % and 28 %, respectively. Xylose release from ND-BSKP and ND-BHKP increased by 47 % and 57 %, respectively, highlighting the potential of PcaLOOLs to enhance hemicellulose recovery. Scanning electron microscopy and fiber image analysis revealed fibrillation and curlation of ND-BSKP after PcaLOOL treatment, consistent with increasing enzyme accessibility to targeted substrates.
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Affiliation(s)
- Deepika Dahiya
- Department of Bioproducts and Biosystems, Aalto University, Kemistintie 1, 02150 Espoo, Finland
| | - Taru Koitto
- Department of Bioproducts and Biosystems, Aalto University, Kemistintie 1, 02150 Espoo, Finland
| | - Kim Kutvonen
- Department of Bioproducts and Biosystems, Aalto University, Kemistintie 1, 02150 Espoo, Finland
| | - Yan Wang
- Biorefining Business Development & Production, St1 Oy, Firdonkatu 2, 00520 Helsinki, Finland
| | - Majid Haddad Momeni
- Department of Bioproducts and Biosystems, Aalto University, Kemistintie 1, 02150 Espoo, Finland
| | - Siiri de Ruijter
- Biorefining Business Development & Production, St1 Oy, Firdonkatu 2, 00520 Helsinki, Finland
| | - Emma R Master
- Department of Bioproducts and Biosystems, Aalto University, Kemistintie 1, 02150 Espoo, Finland; Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, M5S 3E5 Toronto, Ontario, Canada.
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2
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Xu C, Xia T, Peng H, Liu P, Wang Y, Wang Y, Kang H, Tang J, Nauman Aftab M, Peng L. BsEXLX of engineered Trichoderma reesei strain as dual-active expansin to boost cellulases secretion for synergistic enhancement of biomass enzymatic saccharification in corn and Miscanthus straws. BIORESOURCE TECHNOLOGY 2023; 376:128844. [PMID: 36906237 DOI: 10.1016/j.biortech.2023.128844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 03/03/2023] [Accepted: 03/04/2023] [Indexed: 06/18/2023]
Abstract
In this study, bacterial BsEXLE1 gene was overexpressed into T. reesei (Rut-C30) to generate a desirable engineered TrEXLX10 strain. While incubated with alkali-pretreated Miscanthus straw as carbon source, the TrEXLX10 secreted the β-glucosidases, cellobiohydrolases and xylanses with activities raised by 34%, 82% and 159% compared to the Rut-C30. Supplying EXLX10-secreted crude enzymes and commercial mixed-cellulases for two-step lignocellulose hydrolyses of corn and Miscanthus straws after mild alkali pretreatments, this work measured consistently higher hexoses yields released by the EXLX10-secreted enzymes for synergistic enhancements of biomass saccharification in all parallel experiments examined. Meanwhile, this study detected that the expansin, purified from EXLX10-secreted solution, was of exceptionally high binding activities with wall polymers, and further determined its independent enhancement for cellulose hydrolysis. Therefore, this study raised a mechanism model to highlight EXLX/expansin dual-activation roles for both secretion of stable biomass-degradation enzymes at high activity and biomass enzymatic saccharification in bioenergy crops.
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Affiliation(s)
- Chengbao Xu
- Key Laboratory of Fermentation Engineering (Ministry of Education), National "111" Center for Cellular Regulation & Molecular Pharmaceutics, Cooperative Innovation Center of Industrial Fermentation (Ministry of Education & Hubei Province), Hubei Key Laboratory of Industrial Microbiology, College of Biotechnology & Food Science, Hubei University of Technology, Wuhan 430068, China; Biomass & Bioenergy Research Centre, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, China; School of Basic Medical Sciences, Hubei University of Medicine, Shiyan 442000, China
| | - Tao Xia
- Biomass & Bioenergy Research Centre, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, China; College of Life Science & Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Hao Peng
- Key Laboratory of Fermentation Engineering (Ministry of Education), National "111" Center for Cellular Regulation & Molecular Pharmaceutics, Cooperative Innovation Center of Industrial Fermentation (Ministry of Education & Hubei Province), Hubei Key Laboratory of Industrial Microbiology, College of Biotechnology & Food Science, Hubei University of Technology, Wuhan 430068, China; Biomass & Bioenergy Research Centre, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Peng Liu
- Key Laboratory of Fermentation Engineering (Ministry of Education), National "111" Center for Cellular Regulation & Molecular Pharmaceutics, Cooperative Innovation Center of Industrial Fermentation (Ministry of Education & Hubei Province), Hubei Key Laboratory of Industrial Microbiology, College of Biotechnology & Food Science, Hubei University of Technology, Wuhan 430068, China; Biomass & Bioenergy Research Centre, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Yihong Wang
- Biomass & Bioenergy Research Centre, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Yanting Wang
- Key Laboratory of Fermentation Engineering (Ministry of Education), National "111" Center for Cellular Regulation & Molecular Pharmaceutics, Cooperative Innovation Center of Industrial Fermentation (Ministry of Education & Hubei Province), Hubei Key Laboratory of Industrial Microbiology, College of Biotechnology & Food Science, Hubei University of Technology, Wuhan 430068, China; Biomass & Bioenergy Research Centre, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Heng Kang
- Key Laboratory of Fermentation Engineering (Ministry of Education), National "111" Center for Cellular Regulation & Molecular Pharmaceutics, Cooperative Innovation Center of Industrial Fermentation (Ministry of Education & Hubei Province), Hubei Key Laboratory of Industrial Microbiology, College of Biotechnology & Food Science, Hubei University of Technology, Wuhan 430068, China; Biomass & Bioenergy Research Centre, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Jingfeng Tang
- Key Laboratory of Fermentation Engineering (Ministry of Education), National "111" Center for Cellular Regulation & Molecular Pharmaceutics, Cooperative Innovation Center of Industrial Fermentation (Ministry of Education & Hubei Province), Hubei Key Laboratory of Industrial Microbiology, College of Biotechnology & Food Science, Hubei University of Technology, Wuhan 430068, China
| | | | - Liangcai Peng
- Key Laboratory of Fermentation Engineering (Ministry of Education), National "111" Center for Cellular Regulation & Molecular Pharmaceutics, Cooperative Innovation Center of Industrial Fermentation (Ministry of Education & Hubei Province), Hubei Key Laboratory of Industrial Microbiology, College of Biotechnology & Food Science, Hubei University of Technology, Wuhan 430068, China; Biomass & Bioenergy Research Centre, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan 430070, China.
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3
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Ding S, Liu X, Hakulinen N, Taherzadeh MJ, Wang Y, Wang Y, Qin X, Wang X, Yao B, Luo H, Tu T. Boosting enzymatic degradation of cellulose using a fungal expansin: Structural insight into the pretreatment mechanism. BIORESOURCE TECHNOLOGY 2022; 358:127434. [PMID: 35680086 DOI: 10.1016/j.biortech.2022.127434] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 06/03/2022] [Accepted: 06/04/2022] [Indexed: 06/15/2023]
Abstract
The recalcitrance of cellulosic biomass greatly hinders its enzymatic degradation. Expansins induce cell wall loosening and promote efficient cellulose utilization; however, the molecular mechanism underlying their action is not well understood. In this study, TlEXLX1, a fungal expansin from Talaromyces leycettanus JCM12802, was characterized in terms of phylogeny, synergy, structure, and mechanism of action. TlEXLX1 displayed varying degrees of synergism with commercial cellulase in the pretreatment of corn straw and filter paper. TlEXLX1 binds to cellulose via domain 2, mediated by CH-π interactions with residues Tyr291, Trp292, and Tyr327. Residues Asp237, Glu238, and Asp248 in domain 1 form hydrogen bonds with glucose units and break the inherent hydrogen bonding within the cellulose matrix. This study identified the expansin amino acid residues crucial for cellulose binding, and elucidated the structure and function of expansins in cell wall networks; this has potential applications in biomass utilization.
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Affiliation(s)
- Sunjia Ding
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Xiaoqing Liu
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Nina Hakulinen
- Department of Chemistry, University of Eastern Finland, Joensuu 80130, Finland
| | | | - Yaru Wang
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Yuan Wang
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Xing Qin
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Xiaolu Wang
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Bin Yao
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Huiying Luo
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Tao Tu
- State Key Laboratory of Animal Nutrition, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
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4
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Zhang P, Cui M, Huang R, Qi W, Thielemans W, He Z, Su R. Enhanced enzymatic hydrolysis of cellulose by endoglucanase via expansin pretreatment and the addition of zinc ions. BIORESOURCE TECHNOLOGY 2021; 333:125139. [PMID: 33882384 DOI: 10.1016/j.biortech.2021.125139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Revised: 04/01/2021] [Accepted: 04/02/2021] [Indexed: 06/12/2023]
Abstract
One of the major limitations of lignocellulose conversion is the relatively low efficiency of cellulases. Expansins can act as an accessory protein to loosen the rigid cellulose structure and promote cellulose hydrolysis. However, the synergistic action of expansin is not well understood. In this study, we employed quartz crystal microbalance with dissipation to real-time monitor the adsorption of Bacillus subtilis expansin (BsEXLX1) and endoglucanase I (Cel7B) and the hydrolysis of cellulose. The effects of pH, temperature, and zinc ions on the initial adsorption rate and adsorption capacity of BsEXLX1 were examined. When 36.5 mM of zinc ions was added, the irreversible adsorption ratio of BsEXLX1 further increased to 4.63 times the value in the absence of zinc ions, whereas the initial adsorption rate and the hydrolysis rate constants of Cel7B could reach 2.16 times and 2.05 times the values in the absence of zinc ions, respectively.
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Affiliation(s)
- Peiqian Zhang
- State Key Laboratory of Chemical Engineering, Tianjin Key Laboratory of Membrane Science and Desalination Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China; Sustainable Materials Lab, Department of Chemical Engineering, KU Leuven, campus Kulak Kortrijk, Etienne Sabbelaan 53, 8500 Kortrijk, Belgium
| | - Mei Cui
- State Key Laboratory of Chemical Engineering, Tianjin Key Laboratory of Membrane Science and Desalination Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China
| | - Renliang Huang
- School of Marine Science and Technology, Tianjin University, Tianjin 300072, PR China
| | - Wei Qi
- State Key Laboratory of Chemical Engineering, Tianjin Key Laboratory of Membrane Science and Desalination Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, PR China
| | - Wim Thielemans
- Sustainable Materials Lab, Department of Chemical Engineering, KU Leuven, campus Kulak Kortrijk, Etienne Sabbelaan 53, 8500 Kortrijk, Belgium
| | - Zhimin He
- State Key Laboratory of Chemical Engineering, Tianjin Key Laboratory of Membrane Science and Desalination Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China
| | - Rongxin Su
- State Key Laboratory of Chemical Engineering, Tianjin Key Laboratory of Membrane Science and Desalination Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, PR China; School of Marine Science and Technology, Tianjin University, Tianjin 300072, PR China; Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, PR China.
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5
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Herburger K, Franková L, Pičmanová M, Loh JW, Valenzuela-Ortega M, Meulewaeter F, Hudson AD, French CE, Fry SC. Hetero-trans-β-Glucanase Produces Cellulose-Xyloglucan Covalent Bonds in the Cell Walls of Structural Plant Tissues and Is Stimulated by Expansin. MOLECULAR PLANT 2020; 13:1047-1062. [PMID: 32376294 PMCID: PMC7339142 DOI: 10.1016/j.molp.2020.04.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 04/17/2020] [Accepted: 04/28/2020] [Indexed: 05/19/2023]
Abstract
Current cell-wall models assume no covalent bonding between cellulose and hemicelluloses such as xyloglucan or mixed-linkage β-d-glucan (MLG). However, Equisetum hetero-trans-β-glucanase (HTG) grafts cellulose onto xyloglucan oligosaccharides (XGOs) - and, we now show, xyloglucan polysaccharide - in vitro, thus exhibiting CXE (cellulose:xyloglucan endotransglucosylase) activity. In addition, HTG also catalyzes MLG-to-XGO bonding (MXE activity). In this study, we explored the CXE action of HTG in native plant cell walls and tested whether expansin exposes cellulose to HTG by disrupting hydrogen bonds. To quantify and visualize CXE and MXE action, we assayed the sequential release of HTG products from cell walls pre-labeled with substrate mimics. We demonstrated covalent cellulose-xyloglucan bonding in plant cell walls and showed that CXE and MXE action was up to 15% and 60% of total transglucanase action, respectively, and peaked in aging, strengthening tissues: CXE in xylem and cells bordering intercellular canals and MXE in sclerenchyma. Recombinant bacterial expansin (EXLX1) strongly augmented CXE activity in vitro. CXE and MXE action in living Equisetum structural tissues potentially strengthens stems, while expansin might augment the HTG-catalyzed CXE reaction, thereby allowing efficient CXE action in muro. Our methods will enable surveys for comparable reactions throughout the plant kingdom. Furthermore, engineering similar hetero-polymer formation into angiosperm crop plants may improve certain agronomic traits such as lodging tolerance.
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Affiliation(s)
- Klaus Herburger
- The Edinburgh Cell Wall Group, Institute of Molecular Plant Sciences, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3BF, United Kingdom.
| | - Lenka Franková
- The Edinburgh Cell Wall Group, Institute of Molecular Plant Sciences, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3BF, United Kingdom
| | - Martina Pičmanová
- The Edinburgh Cell Wall Group, Institute of Molecular Plant Sciences, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3BF, United Kingdom
| | - Jia Wooi Loh
- The Edinburgh Cell Wall Group, Institute of Molecular Plant Sciences, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3BF, United Kingdom
| | - Marcos Valenzuela-Ortega
- Institute of Quantitative Biology, Biochemistry and Biotechnology, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3BF, United Kingdom
| | - Frank Meulewaeter
- BASF, BBCC Innovation Center Gent - Trait Research, 9052 Gent (Zwijnaarde), Belgium
| | - Andrew D Hudson
- The Edinburgh Cell Wall Group, Institute of Molecular Plant Sciences, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3BF, United Kingdom
| | - Christopher E French
- Institute of Quantitative Biology, Biochemistry and Biotechnology, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3BF, United Kingdom; Zhejiang University-University of Edinburgh Joint Research Centre for Engineering Biology, Zhejiang University, Haining, Zhejiang 314400, China
| | - Stephen C Fry
- The Edinburgh Cell Wall Group, Institute of Molecular Plant Sciences, School of Biological Sciences, The University of Edinburgh, Edinburgh EH9 3BF, United Kingdom
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6
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Cui M, Duan Y, Ma Y, Al-Shwafy KWA, Liu Y, Zhao X, Huang R, Qi W, He Z, Su R. Real-Time QCM-D Monitoring of the Adsorption-Desorption of Expansin on Lignin. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:4503-4510. [PMID: 32241112 DOI: 10.1021/acs.langmuir.0c00104] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Expansin has nonhydrolytic disruptive activity and synergistically acts with cellulases to enhance the hydrolysis of cellulose. The adsorption-desorption of expansin on noncellulosic lignin can greatly affect the action of expansin on lignocellulose. In this study, three lignins with different sources (kraft lignin (KL), sodium lignin sulfonate (SLS), and enzymatic hydrolysis lignin (EHL)) were selected as the substrates. The real-time adsorption-desorption of Bacillus subtilis expansin (BsEXLX1) on lignins was monitored using quartz crystal microgravimetry with dissipation (QCM-D). The effects of temperature and Tween 80 on the adsorption-desorption behaviors were also investigated. The results show that BsEXLX1 exhibited high binding ability on lignin and achieved maximum adsorption of 283.2, 273.8, and 266.9 ng cm-2 at 25 °C on KL, SLS, and EHL, respectively. The maximum adsorption decreased to 148.2-192.8 ng cm-2 when the temperature increased from 25 to 45 °C. Moreover, Tween 80 competitively bound to lignin and significantly prevented expansin adsorption. After irreversible adsorption of Tween 80, the maximum adsorption of BsEXLX1 greatly decreased to 33.3, 37.2, and 10.3 ng cm-2 at 25 °C on KL, SLS, and EHL, respectively. Finally, a kinetic model was developed to analyze the adsorption-desorption process of BsEXLX1. BsEXLX1 has a higher adsorption rate constant (kA) and a lower desorption rate constant (kD) on KL than on SLS and EHL. The findings of this study provide useful insights into the adsorption-desorption of expansin on lignin.
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Affiliation(s)
- Mei Cui
- State Key Laboratory of Chemical Engineering, Tianjin Key Laboratory of Membrane Science and Desalination Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Yuhao Duan
- State Key Laboratory of Chemical Engineering, Tianjin Key Laboratory of Membrane Science and Desalination Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Yuanyuan Ma
- Biomass Conversion Laboratory of Tianjin University R&D Center for Petrochemical Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Khaled W A Al-Shwafy
- State Key Laboratory of Chemical Engineering, Tianjin Key Laboratory of Membrane Science and Desalination Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Yudong Liu
- State Key Laboratory of Chemical Engineering, Tianjin Key Laboratory of Membrane Science and Desalination Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Xudong Zhao
- State Key Laboratory of Chemical Engineering, Tianjin Key Laboratory of Membrane Science and Desalination Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Renliang Huang
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, China
| | - Wei Qi
- State Key Laboratory of Chemical Engineering, Tianjin Key Laboratory of Membrane Science and Desalination Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, China
| | - Zhimin He
- State Key Laboratory of Chemical Engineering, Tianjin Key Laboratory of Membrane Science and Desalination Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
| | - Rongxin Su
- State Key Laboratory of Chemical Engineering, Tianjin Key Laboratory of Membrane Science and Desalination Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin 300072, China
- School of Marine Science and Technology, Tianjin University, Tianjin 300072, China
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7
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Zhang P, Ma Y, Cui M, Wang J, Huang R, Su R, Qi W, He Z, Thielemans W. Effect of Sugars on the Real-Time Adsorption of Expansin on Cellulose. Biomacromolecules 2020; 21:1776-1784. [DOI: 10.1021/acs.biomac.9b01694] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Peiqian Zhang
- State Key Laboratory of Chemical Engineering, Tianjin Key Laboratory of Membrane Science and Desalination Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, P.R. China
- Sustainable Materials Lab, Department of Chemical Engineering, KU Leuven, Campus Kulak Kortrijk, Etienne Sabbelaan 53, 8500 Kortrijk, Belgium
| | - Yuanyuan Ma
- Tianjin R&D Center for Petrochemical Technology, Tianjin University, Tianjin 300072, P.R. China
| | - Mei Cui
- State Key Laboratory of Chemical Engineering, Tianjin Key Laboratory of Membrane Science and Desalination Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, P.R. China
| | - Jieying Wang
- State Key Laboratory of Chemical Engineering, Tianjin Key Laboratory of Membrane Science and Desalination Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, P.R. China
| | - Renliang Huang
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, P.R. China
| | - Rongxin Su
- State Key Laboratory of Chemical Engineering, Tianjin Key Laboratory of Membrane Science and Desalination Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, P.R. China
- Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, P.R. China
- School of Marine Science and Technology, Tianjin University, Tianjin 300072, P.R. China
| | - Wei Qi
- State Key Laboratory of Chemical Engineering, Tianjin Key Laboratory of Membrane Science and Desalination Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, P.R. China
- Collaborative Innovation Center of Chemical Science and Engineering, Tianjin 300072, P.R. China
| | - Zhimin He
- State Key Laboratory of Chemical Engineering, Tianjin Key Laboratory of Membrane Science and Desalination Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, P.R. China
| | - Wim Thielemans
- Sustainable Materials Lab, Department of Chemical Engineering, KU Leuven, Campus Kulak Kortrijk, Etienne Sabbelaan 53, 8500 Kortrijk, Belgium
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8
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Duan Y, Ma Y, Zhao X, Huang R, Su R, Qi W, He Z. Real-time adsorption and action of expansin on cellulose. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:317. [PMID: 30479662 PMCID: PMC6249958 DOI: 10.1186/s13068-018-1318-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Accepted: 11/13/2018] [Indexed: 05/02/2023]
Abstract
BACKGROUND Biological pretreatment is an environmentally safe method for disrupting recalcitrant structures of lignocellulose and thereby improving their hydrolysis efficiency. Expansin and expansin-like proteins act synergistically with cellulases during hydrolysis. A systematic analysis of the adsorption behavior and mechanism of action of expansin family proteins can provide a basis for the development of highly efficient pretreatment methods for cellulosic substrates using expansins. RESULTS Adsorption of Bacillus subtilis expansin (BsEXLX1) onto cellulose film under different conditions was monitored in real time using a quartz crystal microbalance with dissipation. A model was established to describe the adsorption of BsEXLX1 onto the film. High temperatures increased the initial adsorption rate while reducing the maximum amount of BsEXLX1 adsorbed onto the cellulose. Non-ionic surfactants (polyethylene glycol 4000 and Tween 80) at low concentrations enhanced BsEXLX1 adsorption; whereas, high concentrations had the opposite effect. However, sodium dodecyl sulfate inhibited adsorption at both low and high concentrations. We also investigated the structural changes of cellulose upon BsEXLX1 adsorption and found that BsEXLX1 adsorption decreased the crystallinity index, disrupted hydrogen bonding, and increased the surface area of cellulose, indicating greater accessibility of the substrate to the protein. CONCLUSIONS These results increase our understanding of the interaction between expansin and cellulose, and provide evidence for expansin treatment as a promising strategy to enhance enzymatic hydrolysis of lignocellulose.
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Affiliation(s)
- Yuhao Duan
- State Key Laboratory of Chemical Engineering, Tianjin Key Laboratory of Membrane Science and Desalination Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 China
| | - Yuanyuan Ma
- Biomass Conversion Laboratory of Tianjin University R&D Center for Petrochemical Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 China
| | - Xudong Zhao
- State Key Laboratory of Chemical Engineering, Tianjin Key Laboratory of Membrane Science and Desalination Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 China
| | - Renliang Huang
- School of Environmental Science and Engineering, Tianjin University, Tianjin, 300072 China
| | - Rongxin Su
- State Key Laboratory of Chemical Engineering, Tianjin Key Laboratory of Membrane Science and Desalination Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, 300072 China
| | - Wei Qi
- State Key Laboratory of Chemical Engineering, Tianjin Key Laboratory of Membrane Science and Desalination Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 China
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, 300072 China
| | - Zhimin He
- State Key Laboratory of Chemical Engineering, Tianjin Key Laboratory of Membrane Science and Desalination Technology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, 300072 China
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9
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Knapp A, Ripphahn M, Volkenborn K, Skoczinski P, Jaeger KE. Activity-independent screening of secreted proteins using split GFP. J Biotechnol 2017; 258:110-116. [PMID: 28619616 DOI: 10.1016/j.jbiotec.2017.05.024] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Revised: 05/31/2017] [Accepted: 05/31/2017] [Indexed: 01/16/2023]
Abstract
The large-scale industrial production of proteins requires efficient secretion, as provided, for instance, by the Sec system of Gram-positive bacteria. Protein engineering approaches to optimize secretion often involve the screening of large libraries, e.g. comprising a target protein fused to many different signal peptides. Respective high-throughput screening methods are usually based on photometric or fluorimetric assays enabling fast and simple determination of enzymatic activities. Here, we report on an alternative method for quantification of secreted proteins based on the split GFP assay. We analyzed the secretion by Bacillus subtilis of a homologous lipase and a heterologous cutinase by determination of GFP fluorescence and enzyme activity assays. Furthermore, we identified from a signal peptide library a variant of the biotechnologically relevant B. subtilis protein swollenin EXLX1 with up to 5-fold increased secretion. Our results demonstrate that the split GFP assay can be used to monitor secretion of enzymatic and non-enzymatic proteins in B. subtilis in a high-throughput manner.
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Affiliation(s)
- Andreas Knapp
- Institute of Molecular Enzyme Technology, Heinrich -Heine -University Düsseldorf, Forschungszentrum Jülich, D-52426 Jülich, Germany
| | - Myriam Ripphahn
- Institute of Molecular Enzyme Technology, Heinrich -Heine -University Düsseldorf, Forschungszentrum Jülich, D-52426 Jülich, Germany
| | - Kristina Volkenborn
- Institute of Molecular Enzyme Technology, Heinrich -Heine -University Düsseldorf, Forschungszentrum Jülich, D-52426 Jülich, Germany
| | - Pia Skoczinski
- Institute of Molecular Enzyme Technology, Heinrich -Heine -University Düsseldorf, Forschungszentrum Jülich, D-52426 Jülich, Germany
| | - Karl-Erich Jaeger
- Institute of Molecular Enzyme Technology, Heinrich -Heine -University Düsseldorf, Forschungszentrum Jülich, D-52426 Jülich, Germany; Institute of Bio- and Geosciences IBG-1: Biotechnology, Forschungszentrum Jülich GmbH, D-52428 Jülich, Germany.
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10
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Wang Q, Chen L, Lin H, Yu D, Shen Q, Wan L, Zhao Y. The binding, synergistic and structural characteristics of BsEXLX1 for loosening the main components of lignocellulose: Lignin, xylan, and cellulose. Enzyme Microb Technol 2016; 92:67-75. [DOI: 10.1016/j.enzmictec.2016.06.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 06/27/2016] [Accepted: 06/27/2016] [Indexed: 01/03/2023]
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11
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Sun P, Lin H, Wang G, Zhang X, Zhang Q, Zhao Y. Wheat Bran Enhances the Cytotoxicity of Immobilized Alcaligenes aquatilis F8 against Microcystis aeruginosa. PLoS One 2015; 10:e0136429. [PMID: 26295573 PMCID: PMC4546564 DOI: 10.1371/journal.pone.0136429] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Accepted: 08/03/2015] [Indexed: 12/02/2022] Open
Abstract
Algicidal bacteria offer a promising option for killing cyanobacteria. Therefore, a new Alcaligenes aquatilis strain F8 was isolated to control Microcystis aeruginosa in this study. The algicidal activity of strain F8 was dependent on the cell density of M. aeruginosa, and the maximal algicidal rate of the free bacterium reached 88.45% within 72 h. With a view to its application to the control of M. aeruginosa in the natural environment, strain F8 was immobilized in sodium alginate beads, but immobilization of the strain decreased its algicidal rate compared to that of the free bacterium. However, addition of wheat bran to the sodium alginate matrix used to immobilize strain F8 not only eliminated the adverse effects of immobilization on the bacteria but also resulted in an 8.83% higher algicidal rate of the immobilized than free bacteria. Exclusion and recovery methods were used to identify key ingredients of wheat bran and gain insight into the mechanism underlying the observed enhancement of algicidal activity. This analysis indicated that certain factors in wheat bran, including vitamins B1, B2, B9, and E were responsible for promoting bacterial growth and thereby improving the algicidal rate of immobilized strain F8. Our findings indicate that wheat bran is able to improve the algicidal efficiency of A. aquatilis strain F8 for killing M. aeruginosa and is a good source of not only carbon and nitrogen but also vitamins for bacteria.
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Affiliation(s)
- Pengfei Sun
- College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Hui Lin
- Institute of Environment Resource and Soil Fertilizer, Zhejiang Academy of Agriculture Science, Hangzhou, Zhejiang, China
| | - Guan Wang
- College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Ximing Zhang
- College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
| | - Qichun Zhang
- College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, Zhejiang, China
- * E-mail: (QCZ); (YHZ)
| | - Yuhua Zhao
- College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
- * E-mail: (QCZ); (YHZ)
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12
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Junior AT, Dolce LG, de Oliveira Neto M, Polikarpov I. Xanthomonas campestris expansin-like X domain is a structurally disordered beta-sheet macromolecule capable of synergistically enhancing enzymatic efficiency of cellulose hydrolysis. Biotechnol Lett 2015; 37:2419-26. [DOI: 10.1007/s10529-015-1927-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2015] [Accepted: 08/04/2015] [Indexed: 01/30/2023]
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13
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Research advances in expansins and expansion-like proteins involved in lignocellulose degradation. Biotechnol Lett 2015; 37:1541-51. [DOI: 10.1007/s10529-015-1842-0] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Accepted: 04/29/2015] [Indexed: 12/12/2022]
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14
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Kim IJ, Nam KH, Yun EJ, Kim S, Youn HJ, Lee HJ, Choi IG, Kim KH. Optimization of synergism of a recombinant auxiliary activity 9 from Chaetomium globosum with cellulase in cellulose hydrolysis. Appl Microbiol Biotechnol 2015; 99:8537-47. [PMID: 25936375 PMCID: PMC4768223 DOI: 10.1007/s00253-015-6592-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2015] [Revised: 03/14/2015] [Accepted: 04/01/2015] [Indexed: 01/16/2023]
Abstract
Auxiliary activity family 9 (AA9, formerly known as glycoside hydrolase family 61 or polysaccharide monooxygenase) is a group of fungal proteins that were recently found to have a significant synergism with cellulase in cellulose hydrolysis via the oxidative cleavage of glycosidic bonds of cellulose chains. In this study, we report the active expression of a recombinant fungal AA9 from Chaetomium globosum (CgAA9) in a bacterial host, Escherichia coli, and the optimization of its synergistic activity in cellulose hydrolysis by using cellulase. The recombinant CgAA9 (0.9 mg/g cellulose) exhibited 1.7-fold synergism in the hydrolysis of Avicel when incubated with 0.9 filter paper units of Celluclast 1.5 L/g cellulose. The first study of the active expression of AA9 using a bacterial host and its synergistic optimization could be useful for the industrial application of AA9 for the saccharification of lignocellulose.
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Affiliation(s)
- In Jung Kim
- Department of Biotechnology, Korea University Graduate School, Seoul, 136-713, Republic of Korea
| | - Ki Hyun Nam
- Pohang Accelerator Laboratory, Pohang University of Science and Technology, Pohang, 790-784, Republic of Korea
| | - Eun Ju Yun
- Department of Biotechnology, Korea University Graduate School, Seoul, 136-713, Republic of Korea
| | - Sooah Kim
- Department of Biotechnology, Korea University Graduate School, Seoul, 136-713, Republic of Korea
| | - Hak Jin Youn
- Department of Biotechnology, Korea University Graduate School, Seoul, 136-713, Republic of Korea
| | - Hee Jin Lee
- Department of Biotechnology, Korea University Graduate School, Seoul, 136-713, Republic of Korea
| | - In-Geol Choi
- Department of Biotechnology, Korea University Graduate School, Seoul, 136-713, Republic of Korea
| | - Kyoung Heon Kim
- Department of Biotechnology, Korea University Graduate School, Seoul, 136-713, Republic of Korea.
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15
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Georgelis N, Nikolaidis N, Cosgrove DJ. Bacterial expansins and related proteins from the world of microbes. Appl Microbiol Biotechnol 2015; 99:3807-23. [PMID: 25833181 PMCID: PMC4427351 DOI: 10.1007/s00253-015-6534-0] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Revised: 03/05/2015] [Accepted: 03/09/2015] [Indexed: 12/31/2022]
Abstract
The discovery of microbial expansins emerged from studies of the mechanism of plant cell growth and the molecular basis of plant cell wall extensibility. Expansins are wall-loosening proteins that are universal in the plant kingdom and are also found in a small set of phylogenetically diverse bacteria, fungi, and other organisms, most of which colonize plant surfaces. They loosen plant cell walls without detectable lytic activity. Bacterial expansins have attracted considerable attention recently for their potential use in cellulosic biomass conversion for biofuel production, as a means to disaggregate cellulosic structures by nonlytic means ("amorphogenesis"). Evolutionary analysis indicates that microbial expansins originated by multiple horizontal gene transfers from plants. Crystallographic analysis of BsEXLX1, the expansin from Bacillus subtilis, shows that microbial expansins consist of two tightly packed domains: the N-terminal domain D1 has a double-ψ β-barrel fold similar to glycosyl hydrolase family-45 enzymes but lacks catalytic residues usually required for hydrolysis; the C-terminal domain D2 has a unique β-sandwich fold with three co-linear aromatic residues that bind β-1,4-glucans by hydrophobic interactions. Genetic deletion of expansin in Bacillus and Clavibacter cripples their ability to colonize plant tissues. We assess reports that expansin addition enhances cellulose breakdown by cellulase and compare expansins with distantly related proteins named swollenin, cerato-platanin, and loosenin. We end in a speculative vein about the biological roles of microbial expansins and their potential applications. Advances in this field will be aided by a deeper understanding of how these proteins modify cellulosic structures.
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Affiliation(s)
| | - Nikolas Nikolaidis
- Department of Biological Science, California State University, Fullerton, CA 92831, USA
| | - Daniel J. Cosgrove
- Department of Biology, Penn State University, University Park, PA 16802, USA
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16
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Payne CM, Knott BC, Mayes HB, Hansson H, Himmel ME, Sandgren M, Ståhlberg J, Beckham GT. Fungal Cellulases. Chem Rev 2015; 115:1308-448. [DOI: 10.1021/cr500351c] [Citation(s) in RCA: 533] [Impact Index Per Article: 59.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Christina M. Payne
- Department
of Chemical and Materials Engineering and Center for Computational
Sciences, University of Kentucky, 177 F. Paul Anderson Tower, Lexington, Kentucky 40506, United States
| | - Brandon C. Knott
- National
Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver
West Parkway, Golden, Colorado 80401, United States
| | - Heather B. Mayes
- Department
of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Henrik Hansson
- Department
of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, Uppsala BioCenter, Almas allé 5, SE-75651 Uppsala, Sweden
| | - Michael E. Himmel
- Biosciences
Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States
| | - Mats Sandgren
- Department
of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, Uppsala BioCenter, Almas allé 5, SE-75651 Uppsala, Sweden
| | - Jerry Ståhlberg
- Department
of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, Uppsala BioCenter, Almas allé 5, SE-75651 Uppsala, Sweden
| | - Gregg T. Beckham
- National
Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver
West Parkway, Golden, Colorado 80401, United States
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17
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Seki Y, Kikuchi Y, Yoshimoto R, Aburai K, Kanai Y, Ruike T, Iwabata K, Goitsuka R, Sugawara F, Abe M, Sakaguchi K. Promotion of crystalline cellulose degradation by expansins from Oryza sativa. PLANTA 2015; 241:83-93. [PMID: 25218793 DOI: 10.1007/s00425-014-2163-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Accepted: 08/22/2014] [Indexed: 06/03/2023]
Abstract
Enzymatic activities of Oryza sativa expansins, which were heterologously overexpressed in Escherichia coli , were analyzed. Results suggested that expansins promote degradation of cellulose by cellulase in a synergistic manner. Sustainable production of future biofuels is dependent on efficient saccharification of lignocelluloses. Expansins have received a lot of attention as proteins promoting biological degradation of cellulose using cellulase. The expansins are a class of plant cell wall proteins that induce cell wall loosening without hydrolysis. In this study, the expansins from Oryza sativa were classified using phylogenetic analysis and five proteins were selected for functional evaluation. At low cellulose loading, the cellulase in expansin mixtures was up to 2.4 times more active than in mixtures containing only cellulase, but at high cellulose loading the activity of cellulase in expansin mixtures and cellulase only mixtures did not differ. Furthermore, expansin activity was greater in cellulase mixtures compared with cellulase-deficient mixtures. Therefore, the expansins showed significant synergistic activity with cellulase. Expansin may play an important role in efficient saccharification of cellulose.
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Affiliation(s)
- Yasutaka Seki
- Department of Applied Biological Science, Faculty of Science and Technology, Tokyo University of Science, 2641 Yamazaki, Noda-shi, Chiba-Ken, 278-8510, Japan,
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18
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Extracellular secretion of noncatalytic plant cell wall-binding proteins by the cellulolytic thermophile Caldicellulosiruptor bescii. J Bacteriol 2014; 196:3784-92. [PMID: 25157080 DOI: 10.1128/jb.01897-14] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Caldicellulosiruptor bescii efficiently degrades cellulose, xylan, and native grasses at high temperatures above 70°C under anaerobic conditions. C. bescii extracellularly secretes multidomain glycoside hydrolases along with proteins of unknown function. In this study, we analyzed the C. bescii proteins that bind to the cell walls of timothy grass by using mass spectrometry, and we identified four noncatalytic plant cell wall-binding proteins (PWBPs) with high pI values (9.2 to 9.6). A search of a conserved domain database showed that these proteins possess a common domain related to solute-binding proteins. In addition, 12 genes encoding PWBP-like proteins were detected in the C. bescii genomic sequence. To analyze the binding properties of PWBPs, recombinant PWBP57 and PWBP65, expressed in Escherichia coli, were prepared. The PWBPs displayed a wide range of binding specificities: they bound to cellulose, lichenan, xylan, arabinoxylan, glucuronoxylan, mannan, glucomannan, pectin, oligosaccharides, and the cell walls of timothy grass. The proteins showed the highest binding affinity for the plant cell wall, with association constant (Ka) values of 5.2 × 10(6) to 44 × 10(6) M(-1) among the insoluble polysaccharides tested, as measured using depletion binding isotherms. Affinity gel electrophoresis demonstrated that the proteins bound to the acidic polymer pectin most strongly among the soluble polysaccharides tested. Fluorescence microscopic analysis showed that the proteins bound preferentially to the cell wall in a section of grass leaf. Binding of noncatalytic PWBPs with high pI values might be necessary for efficient utilization of polysaccharides by C. bescii at high temperatures.
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19
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Kim IJ, Lee HJ, Choi IG, Kim KH. Synergistic proteins for the enhanced enzymatic hydrolysis of cellulose by cellulase. Appl Microbiol Biotechnol 2014; 98:8469-80. [PMID: 25129610 DOI: 10.1007/s00253-014-6001-3] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Revised: 07/28/2014] [Accepted: 07/29/2014] [Indexed: 01/09/2023]
Abstract
Reducing the enzyme loadings for enzymatic saccharification of lignocellulose is required for economically feasible production of biofuels and biochemicals. One strategy is addition of small amounts of synergistic proteins to cellulase mixtures. Synergistic proteins increase the activity of cellulase without causing significant hydrolysis of cellulose. Synergistic proteins exert their activity by inducing structural modifications in cellulose. Recently, synergistic proteins from various biological sources, including bacteria, fungi, and plants, were identified based on genomic data, and their synergistic activities were investigated. Currently, an up-to-date overview of several aspects of synergistic proteins, such as their functions, action mechanisms and synergistic activity, are important for future industrial application. In this review, we summarize the current state of research on four synergistic proteins: carbohydrate-binding modules, plant expansins, expansin-like proteins, and Auxiliary Activity family 9 (formerly GH61) proteins. This review provides critical information to aid in promoting research on the development of efficient and industrially feasible synergistic proteins.
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Affiliation(s)
- In Jung Kim
- Department of Biotechnology, Korea University Graduate School, Seoul, 136-713, Republic of Korea
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20
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Heterologous expression and functional characterization of a novel cellulose-disruptive protein LeEXP2 from Lycopersicum esculentum. J Biotechnol 2014; 186:148-55. [PMID: 25041860 DOI: 10.1016/j.jbiotec.2014.07.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 06/01/2014] [Accepted: 07/08/2014] [Indexed: 01/01/2023]
Abstract
There has been little research reported on the synergism of plant expansins in cellulose hydrolysis because of the difficulty of heterologous expression. In this study, the expansin gene LeExp2 of Lycopersicum esculentum was expressed for the first time in Pichia pastoris to identify its function in vitro. The optimal expression level was obtained by adding PMSF and a commercial protease inhibitor, and the maximum expression level was 70.9 mg/L. The affinity-purified LeEXP2 displayed cellulose-weakening activity and synergism with cellulase, and the reducing sugar yield in the reaction mixture with LeEXP2 was 1.4-9.8-fold that of control. The optimum pH and temperature for reducing-sugar liberation by LeEXP2 and endoglucanase were pH 4.8 and 50 °C. Cu(2+) and Fe(2+) notably increased the synergistic activity of LeEXP2, and Co(2+) enhanced the activity of endoglucanase but failed to improve synergism. LeEXP2 exhibited a high level of robustness to reagents and heat, indicating its potential application for cellulose decomposition. LeEXP2 preferentially bound to cellulose over lignin, and the binding capability to given substrates was not related to the crystallinity. This is the first study to characterize the functional role of LeEXP2 in cellulose degradation.
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21
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Olarte-Lozano M, Mendoza-Nuñez MA, Pastor N, Segovia L, Folch-Mallol J, Martínez-Anaya C. PcExl1 a novel acid expansin-like protein from the plant pathogen Pectobacterium carotovorum, binds cell walls differently to BsEXLX1. PLoS One 2014; 9:e95638. [PMID: 24755657 PMCID: PMC3995998 DOI: 10.1371/journal.pone.0095638] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Accepted: 03/28/2014] [Indexed: 12/20/2022] Open
Abstract
Microbial expansins act on plant cell walls similarly to plant expansins, albeit their loosening activity levels are tenfold lesser compared to plant expansins. We report the characterization of an expansin-like gene from the plant pathogen Pectobacterium carotovorum, named exl1. PcExl1 is an acidic protein that binds cellulose (Avicel), and weakens filter paper. The acidic nature of PcExl1 confers different binding properties when compared to Bacillus subtilis BsEXLX1, which is a basic protein. PcExl1 binding to wheat cell wall increased when acidic components were depleted, reaching a similar level to the binding to Avicel, indicating that cellulose is the target of PcExl1.
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Affiliation(s)
- Miguel Olarte-Lozano
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
- Centro de Investigación en Biotecnología, Universidad Autónoma del Estado de Morelos, Cuernavaca, Morelos, México
| | - Mario A. Mendoza-Nuñez
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Nina Pastor
- Facultad de Ciencias, Universidad Autónoma del Estado de Morelos, Cuernavaca, Morelos, México
| | - Lorenzo Segovia
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Jorge Folch-Mallol
- Centro de Investigación en Biotecnología, Universidad Autónoma del Estado de Morelos, Cuernavaca, Morelos, México
| | - Claudia Martínez-Anaya
- Departamento de Ingeniería Celular y Biocatálisis, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
- * E-mail:
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