1
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McDonough R, Williams CC, Hartley CJ, French N, Scott C, Lewis DA. Kinetic Model for the Heterogeneous Biocatalytic Reactions Using Tethered Cofactors. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:6685-6693. [PMID: 38525517 DOI: 10.1021/acs.langmuir.3c02958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/26/2024]
Abstract
Understanding the mechanism of interfacial enzyme kinetics is critical to the development of synthetic biological systems for the production of value-added chemicals. Here, the interfacial kinetics of the catalysis of β-nicotinamide adenine dinucleotide (NAD+)-dependent enzymes acting on NAD+ tethered to the surface of silica nanoparticles (SiNPs) has been investigated using two complementary and supporting kinetic approaches: enzyme excess and reactant (NAD+) excess. Kinetic models developed for these two approaches characterize several critical reaction steps including reversible enzyme adsorption, complexation, decomplexation, and catalysis of the surface-bound enzyme/NAD+ complex. The analysis reveals a concentrating effect resulting in a very high local concentration of enzyme and cofactor on the particle surface, in which the enzyme is saturated by surface-bound NAD, facilitating a rate enhancement of enzyme/NAD+ complexation and catalysis. This resulted in high enzyme efficiency within the tethered NAD+ system compared to that of the free enzyme/NAD+ system, which increases with decreasing enzyme concentration. The role of enzyme adsorption onto solid substrates with a tethered catalyst (such as NAD+) has potential for creating highly efficient flow biocatalytic systems.
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Affiliation(s)
- Rowan McDonough
- Institute for Nanoscale Science and Technology, School of Chemical and Physical Sciences, Flinders University, Bedford Park, SA 5042, Australia
| | | | | | - Nigel French
- CSIRO Environment, Black Mountain, ACT 2601, Australia
| | - Colin Scott
- CSIRO Environment, Black Mountain, ACT 2601, Australia
| | - David A Lewis
- Institute for Nanoscale Science and Technology, School of Chemical and Physical Sciences, Flinders University, Bedford Park, SA 5042, Australia
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2
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Wasilewska M, Dąbkowska M, Pomorska A, Batys P, Kowalski B, Michna A, Adamczyk Z. Mechanisms of Fibroblast Growth Factor 21 Adsorption on Macroion Layers: Molecular Dynamics Modeling and Kinetic Measurements. Biomolecules 2023; 13:1709. [PMID: 38136581 PMCID: PMC10741725 DOI: 10.3390/biom13121709] [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: 10/27/2023] [Revised: 11/20/2023] [Accepted: 11/21/2023] [Indexed: 12/24/2023] Open
Abstract
Molecular dynamic modeling and various experimental techniques, including multi-angle dynamic light scattering (MADLS), streaming potential, optical waveguide light spectroscopy (OWLS), quartz crystal microbalance with dissipation (QCM), and atomic force microscopy (AFM), were applied to determine the basic physicochemical parameters of fibroblast growth factor 21 in electrolyte solutions. The protein size and shape, cross-section area, dependence of the nominal charge on pH, and isoelectric point of 5.3 were acquired. These data enabled the interpretation of the adsorption kinetics of FGF 21 on bare and macrocation-covered silica investigated by OWLS and QCM. It was confirmed that the protein molecules irreversibly adsorbed on the latter substrate, forming layers with controlled coverage up to 0.8 mg m-2, while their adsorption on bare silica was much smaller. The viability of two cell lines, CHO-K1 and L-929, on both bare and macrocation/FGF 21-covered substrates was also determined. It is postulated that the acquired results can serve as useful reference systems for designing complexes that can extend the half-life of FGF 21 in its active state.
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Affiliation(s)
- Monika Wasilewska
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Niezapominajek 8, 30-239 Krakow, Poland; (M.W.); (A.P.); (P.B.)
| | - Maria Dąbkowska
- Independent Laboratory of Pharmacokinetic and Clinical Pharmacy, Pomeranian Medical University, Rybacka 1, 70-204 Szczecin, Poland; (M.D.); (B.K.)
| | - Agata Pomorska
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Niezapominajek 8, 30-239 Krakow, Poland; (M.W.); (A.P.); (P.B.)
| | - Piotr Batys
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Niezapominajek 8, 30-239 Krakow, Poland; (M.W.); (A.P.); (P.B.)
| | - Bogusław Kowalski
- Independent Laboratory of Pharmacokinetic and Clinical Pharmacy, Pomeranian Medical University, Rybacka 1, 70-204 Szczecin, Poland; (M.D.); (B.K.)
| | - Aneta Michna
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Niezapominajek 8, 30-239 Krakow, Poland; (M.W.); (A.P.); (P.B.)
| | - Zbigniew Adamczyk
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Niezapominajek 8, 30-239 Krakow, Poland; (M.W.); (A.P.); (P.B.)
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3
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Michna A, Pomorska A, Ozcan O. Biocompatible Macroion/Growth Factor Assemblies for Medical Applications. Biomolecules 2023; 13:biom13040609. [PMID: 37189357 DOI: 10.3390/biom13040609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Revised: 03/24/2023] [Accepted: 03/26/2023] [Indexed: 03/31/2023] Open
Abstract
Growth factors are a class of proteins that play a role in the proliferation (the increase in the number of cells resulting from cell division) and differentiation (when a cell undergoes changes in gene expression becoming a more specific type of cell) of cells. They can have both positive (accelerating the normal healing process) and negative effects (causing cancer) on disease progression and have potential applications in gene therapy and wound healing. However, their short half-life, low stability, and susceptibility to degradation by enzymes at body temperature make them easily degradable in vivo. To improve their effectiveness and stability, growth factors require carriers for delivery that protect them from heat, pH changes, and proteolysis. These carriers should also be able to deliver the growth factors to their intended destination. This review focuses on the current scientific literature concerning the physicochemical properties (such as biocompatibility, high affinity for binding growth factors, improved bioactivity and stability of the growth factors, protection from heat, pH changes or appropriate electric charge for growth factor attachment via electrostatic interactions) of macroions, growth factors, and macroion-growth factor assemblies, as well as their potential uses in medicine (e.g., diabetic wound healing, tissue regeneration, and cancer therapy). Specific attention is given to three types of growth factors: vascular endothelial growth factors, human fibroblast growth factors, and neurotrophins, as well as selected biocompatible synthetic macroions (obtained through standard polymerization techniques) and polysaccharides (natural macroions composed of repeating monomeric units of monosaccharides). Understanding the mechanisms by which growth factors bind to potential carriers could lead to more effective delivery methods for these proteins, which are of significant interest in the diagnosis and treatment of neurodegenerative and civilization diseases, as well as in the healing of chronic wounds.
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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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Anuganti M, Fu H, Ekatan S, Kumar CV, Lin Y. Kinetic Study on Enzymatic Hydrolysis of Cellulose in an Open, Inhibition-Free System. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:5180-5192. [PMID: 33872034 DOI: 10.1021/acs.langmuir.1c00115] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Due to the complexity of cellulases and the requirement of enzyme adsorption on cellulose prior to reactions, it is difficult to evaluate their reaction with a general mechanistic scheme. Nevertheless, it is of great interest to come up with an approximate analytic description of a valid model for the purpose of developing an intuitive understanding of these complex enzyme systems. Herein, we used the surface plasmonic resonance method to monitor the action of a cellobiohydrolase by itself, as well as its mixture with a synergetic endoglucanase, on the surface of a regenerated model cellulose film, under continuous flow conditions. We found a phenomenological approach by taking advantage of the long steady state of cellulose hydrolysis in the open, inhibition-free system. This provided a direct and reliable way to analyze the adsorption and reaction processes with a minimum number of fitting parameters. We investigated a generalized Langmuir-Michaelis-Menten model to describe a full set of kinetic results across a range of enzyme concentrations, compositions, and temperatures. The overall form of the equations describing the pseudo-steady-state kinetics of the flow-system shares some interesting similarities with the Michaelis-Menten equation. The use of familiar Michaelis-Menten parameters in the analysis provides a unifying framework to study cellulase kinetics. The strategy may provide a shortcut for approaching a quantitative while intuitive understanding of enzymatic degradation of cellulose from top to bottom. The open system approach and the kinetic analysis should be applicable to a variety of cellulases and reaction systems to accelerate the progress in the field.
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Affiliation(s)
- Murali Anuganti
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Hailin Fu
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Stephen Ekatan
- Polymer Program, Institute of Material Sciences, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Challa V Kumar
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
| | - Yao Lin
- Department of Chemistry, University of Connecticut, Storrs, Connecticut 06269, United States
- Polymer Program, Institute of Material Sciences, University of Connecticut, Storrs, Connecticut 06269, United States
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6
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Zheng P, Xiang L, Chang J, Lin Q, Xie L, Lan T, Liu J, Gong Z, Tang T, Shuai L, Luo X, Chen N, Zeng H. Nanomechanics of Lignin-Cellulase Interactions in Aqueous Solutions. Biomacromolecules 2021; 22:2033-2042. [PMID: 33880924 DOI: 10.1021/acs.biomac.1c00140] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Efficient enzymatic hydrolysis of cellulose in lignocellulose to glucose is one of the most critical steps for the production of biofuels. The nonproductive adsorption of lignin to expensive cellulase highly impedes the development of biorefinery. Understanding the lignin-cellulase interaction mechanism serves as a vital basis for reducing such nonproductive adsorption in their practical applications. Yet, limited report is available on the direct characterization of the lignin-cellulase interactions. Herein, for the first time, the nanomechanics of the biomacromolecules including lignin, cellulase, and cellulose were systematically investigated by using a surface force apparatus (SFA) at the nanoscale in aqueous solutions. Interestingly, a cation-π interaction was discovered and demonstrated between lignin and cellulase molecules through SFA measurements with the addition of different cations (Na+, K+, etc.). The complementary adsorption tests and theoretical calculations further confirmed the validity of the force measurement results. This finding further inspired the investigation of the interaction between lignin and other noncatalytic-hydrolysis protein (i.e., soy protein). Soy protein was demonstrated as an effective, biocompatible, and inexpensive lignin-blocker based on the molecular force measurements through the combined effects of electrostatic, cation-π, and hydrophobic interactions, which significantly improved the enzymatic hydrolysis efficiencies of cellulose in pretreated lignocellulosic substrates. Our results offer quantitative information on the fundamental understanding of the lignin-cellulase interaction mechanism. Such unraveled nanomechanics provides new insights into the development of advanced biotechnologies for addressing the nonproductive adsorption of lignin to cellulase, with great implications on improving the economics of lignocellulosic biorefinery.
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Affiliation(s)
- Peitao Zheng
- College of Material Engineering, Fujian Agriculture and Forestry University, 15 Shangxiadian Road, Fuzhou, Fujian 350002, P. R. China.,Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2V4, Canada
| | - Li Xiang
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2V4, Canada
| | - Jian Chang
- Department of Materials Science & Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Qiaojia Lin
- College of Material Engineering, Fujian Agriculture and Forestry University, 15 Shangxiadian Road, Fuzhou, Fujian 350002, P. R. China
| | - Lei Xie
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2V4, Canada
| | - Tu Lan
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2V4, Canada.,Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Jing Liu
- College of Material Engineering, Fujian Agriculture and Forestry University, 15 Shangxiadian Road, Fuzhou, Fujian 350002, P. R. China
| | - Zhenggang Gong
- College of Material Engineering, Fujian Agriculture and Forestry University, 15 Shangxiadian Road, Fuzhou, Fujian 350002, P. R. China
| | - Tian Tang
- Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta T6G 1H9, Canada
| | - Li Shuai
- College of Material Engineering, Fujian Agriculture and Forestry University, 15 Shangxiadian Road, Fuzhou, Fujian 350002, P. R. China
| | - Xiaolin Luo
- College of Material Engineering, Fujian Agriculture and Forestry University, 15 Shangxiadian Road, Fuzhou, Fujian 350002, P. R. China.,Jiangsu Provincial Key Laboratory of Pulp and Paper Science and Technology, Nanjing Forestry University, Nanjing, Jiangsu 210037, China
| | - Nairong Chen
- College of Material Engineering, Fujian Agriculture and Forestry University, 15 Shangxiadian Road, Fuzhou, Fujian 350002, P. R. China
| | - Hongbo Zeng
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2V4, Canada
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7
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Zhang P, Su R, Duan Y, Cui M, Huang R, Qi W, He Z, Thielemans W. Synergy between endo/exo-glucanases and expansin enhances enzyme adsorption and cellulose conversion. Carbohydr Polym 2021; 253:117287. [DOI: 10.1016/j.carbpol.2020.117287] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Revised: 10/01/2020] [Accepted: 10/17/2020] [Indexed: 10/23/2022]
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8
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Baig KS. Interaction of enzymes with lignocellulosic materials: causes, mechanism and influencing factors. BIORESOUR BIOPROCESS 2020. [DOI: 10.1186/s40643-020-00310-0] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AbstractFor the production of biofuel (bioethanol), enzymatic adsorption onto a lignocellulosic biomass surface is a prior condition for the enzymatic hydrolysis process to occur. Lignocellulosic substances are mainly composed of cellulose, hemicellulose and lignin. The polysaccharide matrix (cellulose and hemicellulose) is capable of producing bioethanol. Therefore, lignin is removed or its concentration is reduced from the adsorption substrates by pretreatments. Selected enzymes are used for the production of reducing sugars from cellulosic materials, which in turn are converted to bioethanol. Adsorption of enzymes onto the substrate surface is a complicated process. A large number of research have been performed on the adsorption process, but little has been done to understand the mechanism of adsorption process. This article reviews the mechanisms of adsorption of enzymes onto the biomass surfaces. A conceptual adsorption mechanism is presented which will fill the gaps in literature and help researchers and industry to use adsorption more efficiently. The process of enzymatic adsorption starts with the reciprocal interplay of enzymes and substrates and ends with the establishment of molecular and cellular binding. The kinetics of an enzymatic reaction is almost the same as that of a characteristic chemical catalytic reaction. The influencing factors discussed in detail are: surface characteristics of the participating materials, the environmental factors, such as the associated flow conditions, temperature, concentration, etc. Pretreatment of lignocellulosic materials and optimum range of shear force and temperature for getting better results of adsorption are recommended.
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9
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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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10
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Studies of adsorptive capacity of bacterial β-glucosidases on lignocresol aiming the enzymatic recycling in bioprocesses. ACTA ACUST UNITED AC 2019; 23:e00326. [PMID: 30984571 PMCID: PMC6444126 DOI: 10.1016/j.btre.2019.e00326] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 03/11/2019] [Accepted: 03/19/2019] [Indexed: 11/30/2022]
Abstract
Lignocresol has great capacity for use in recovery and enzymatic recycling in bioprocesses due to its adsorptive capacity. The adsorption of TpBgl3 to Lignocresol is higher compared to TpBgl1. The interactions between lignocresol and enzymes are influenced by electrostatic characteristics, and surface hydrophobicity. Glucose does not affect the adsorption of enzymes onto lignocresol. TpBgl1 bound to lignocresol maintains a residual enzymatic activity.
Enzymes are essential in many biological processes, including second-generation ethanol production. However, enzymes are one of the main expenses for the industrial process in these days. Several studies have been done to maximize cost savings, however, many processes are still economically infeasible. In this study, we report the synthesis of a suspension of lignocresol for recycling or reuse of enzymes in bioprocesses. In this way, it was performed the adsorption assays between lignocresol and β-glucosidases from Thermotoga petrophila, belonging to the families GH1 and GH3, for the development of a lignocresol-enzyme complex. Our results show that lignocresol maintains greater adsorptive capacity for β-glucosidases than lignin. This capacity can be explained both by its great hydrophobicity and also by electrostatic characteristics. Therefore, all these results demonstrate good adsorption of the enzymes to the lignocresol, demonstrating great potential for enzymatic recycling.
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11
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Petrášek Z, Eibinger M, Nidetzky B. Modeling the activity burst in the initial phase of cellulose hydrolysis by the processive cellobiohydrolase Cel7A. Biotechnol Bioeng 2019; 116:515-525. [PMID: 30515756 PMCID: PMC6590443 DOI: 10.1002/bit.26889] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 11/16/2018] [Accepted: 11/29/2018] [Indexed: 01/05/2023]
Abstract
The hydrolysis of cellulose by processive cellulases, such as exocellulase TrCel7A from Trichoderma reesei, is typically characterized by an initial burst of high activity followed by a slowdown, often leading to incomplete hydrolysis of the substrate. The origins of these limitations to cellulose hydrolysis are not yet fully understood. Here, we propose a new model for the initial phase of cellulose hydrolysis by processive cellulases, incorporating a bound but inactive enzyme state. The model, based on ordinary differential equations, accurately reproduces the activity burst and the subsequent slowdown of the cellulose hydrolysis and describes the experimental data equally well or better than the previously suggested model. We also derive steady‐state expressions that can be used to describe the pseudo‐steady state reached after the initial activity burst. Importantly, we show that the new model predicts the existence of an optimal enzyme‐substrate affinity at which the pseudo‐steady state hydrolysis rate is maximized. The model further allows the calculation of glucose production rate from the first cut in the processive run and reproduces the second activity burst commonly observed upon new enzyme addition. These results are expected to be applicable also to other processive enzymes.
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Affiliation(s)
- Zdeneˇk Petrášek
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, NAWI Graz, Graz, Austria
| | - Manuel Eibinger
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, NAWI Graz, Graz, Austria
| | - Bernd Nidetzky
- Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, NAWI Graz, Graz, Austria.,Austrian Centre of Industrial Biotechnology, Graz, Austria
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12
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Zhang P, Chen M, Duan Y, Huang R, Su R, Qi W, Thielemans W, He Z. Real-Time Adsorption of Exo- and Endoglucanases on Cellulose: Effect of pH, Temperature, and Inhibitors. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:13514-13522. [PMID: 30372079 DOI: 10.1021/acs.langmuir.8b02260] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Effective regulation of cellulase adsorption is key to improving the efficiencies of the two major bottlenecks of lignocellulose hydrolysis and cellulase recovery. In this work, we investigated the effect of inhibitors, pH, and temperature on the adsorption of exo- and endoglucanases (Cel7A and Cel7B, respectively) on cellulose using quartz crystal microgravimetry with dissipation. The addition of glucose and cellobiose can both inhibit the hydrolysis activity of Cel7A, whereas only cellobiose can inhibit that of Cel7B. Notably, the adsorption was favored by acidic conditions (pH ≤ 4.8) and low temperature, whereas alkaline conditions (pH 9 and 10) facilitated enzyme desorption, which is useful to guide the process of cellulase recovery. The adsorption and hydrolysis activity of Cel7A and Cel7B were both higher at 45 °C than at 25 °C. These findings pave the way to effective regulation of cellulase adsorption and thus improve lignocellulose conversion and cellulase recovery.
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Affiliation(s)
| | | | | | | | - Rongxin Su
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) , Tianjin 300072 , PR China
| | - Wei Qi
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin) , Tianjin 300072 , PR China
| | - Wim Thielemans
- Renewable Materials and Nanotechnology Group, Department of Chemical Engineering , KU Leuven , Campus Kortrijk, Etienne Sabbelaan 53 , 8500 Kortrijk , Belgium
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13
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Kari J, Olsen JP, Jensen K, Badino SF, Krogh KBRM, Borch K, Westh P. Sabatier Principle for Interfacial (Heterogeneous) Enzyme Catalysis. ACS Catal 2018. [DOI: 10.1021/acscatal.8b03547] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Jeppe Kari
- Research Unit for Functional Biomaterials, Roskilde University, 1 Universitetsvej, DK-4000 Roskilde, Denmark
| | - Johan P. Olsen
- Novozymes A/S, Krogshøjvej 36, DK-2880 Bagsværd, Denmark
| | - Kenneth Jensen
- Novozymes A/S, Krogshøjvej 36, DK-2880 Bagsværd, Denmark
| | - Silke F. Badino
- Research Unit for Functional Biomaterials, Roskilde University, 1 Universitetsvej, DK-4000 Roskilde, Denmark
| | | | - Kim Borch
- Novozymes A/S, Krogshøjvej 36, DK-2880 Bagsværd, Denmark
| | - Peter Westh
- Research Unit for Functional Biomaterials, Roskilde University, 1 Universitetsvej, DK-4000 Roskilde, Denmark
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14
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Gebreyohannes AY, Dharmjeet M, Swusten T, Mertens M, Verspreet J, Verbiest T, Courtin CM, Vankelecom IFJ. Simultaneous glucose production from cellulose and fouling reduction using a magnetic responsive membrane reactor with superparamagnetic nanoparticles carrying cellulolytic enzymes. BIORESOURCE TECHNOLOGY 2018; 263:532-540. [PMID: 29778024 DOI: 10.1016/j.biortech.2018.05.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 04/27/2018] [Accepted: 05/01/2018] [Indexed: 06/08/2023]
Abstract
This work aimed at investigating simultaneous hydrolysis of cellulose and in-situ foulant degradation in a cellulose fed superparamagnetic biocatalytic membrane reactor (BMRSP). In this reactor, a dynamic layer of superparamagnetic bionanocomposites with immobilized cellulolytic enzymes were reversibly immobilized on superparamagnetic polymeric membrane using an external magnetic field. The formation of a dynamic layer of bionanocomposites on the membrane helped to prevent direct membrane-foulant interaction. Due to in-situ biocatalysis, there was limited filtration resistance. Simultaneous separation of the product helped to avoid enzyme product inhibition, achieve constant reaction rate over time and 50% higher enzyme efficiency than batch reactor. Stable enzyme immobilization and the ability to keep enzyme in the system for long period helped to achieve continuous productivity at very low enzyme but high solid loading, while also reducing the extent of membrane fouling. Hence, the BMRSP paves a path for sustainable production of bioethanol from the cheaply available lignocellulose.
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Affiliation(s)
- Abaynesh Yihdego Gebreyohannes
- Centre for Surface Chemistry and Catalysis KU Leuven Chem & Tech, Celestijnenlaan 200F, Postbus 2461 3001 Leuven, Belgium
| | | | - Tom Swusten
- Molecular Imaging and Photonics, Faculty of Bioengineering Sciences, KU Leuven, Celestijnenlaan 200d - Box 2425, 3001 Leuven, Belgium
| | - Matthias Mertens
- Centre for Surface Chemistry and Catalysis KU Leuven Chem & Tech, Celestijnenlaan 200F, Postbus 2461 3001 Leuven, Belgium
| | - Joran Verspreet
- Laboratory of Food Chemistry and Biochemistry & Leuven Food Science and Nutrition Research Centre (LFoRCe), Faculty of Bioengineering Sciences, KU Leuven, Kasteelpark Arenberg 22, PO Box 2463, 3001 Leuven, Belgium
| | - Thierry Verbiest
- Molecular Imaging and Photonics, Faculty of Bioengineering Sciences, KU Leuven, Celestijnenlaan 200d - Box 2425, 3001 Leuven, Belgium
| | - Christophe M Courtin
- Laboratory of Food Chemistry and Biochemistry & Leuven Food Science and Nutrition Research Centre (LFoRCe), Faculty of Bioengineering Sciences, KU Leuven, Kasteelpark Arenberg 22, PO Box 2463, 3001 Leuven, Belgium
| | - Ivo F J Vankelecom
- Centre for Surface Chemistry and Catalysis KU Leuven Chem & Tech, Celestijnenlaan 200F, Postbus 2461 3001 Leuven, Belgium.
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15
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Kansou K, Rémond C, Paës G, Bonnin E, Tayeb J, Bredeweg B. Testing scientific models using Qualitative Reasoning: Application to cellulose hydrolysis. Sci Rep 2017; 7:14122. [PMID: 29074872 PMCID: PMC5658447 DOI: 10.1038/s41598-017-14281-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Accepted: 10/06/2017] [Indexed: 12/17/2022] Open
Abstract
With the accumulation of scientific information in natural science, even experts can find difficult to keep integrating new piece of information. It is critical to explore modelling solutions able to capture information scattered in publications as a computable representation form. Traditional modelling techniques are important in that regard, but relying on numerical information comes with limitations for integrating results from distinct studies, high-level representations can be more suited. We present an approach to stepwise construct mechanistic explanation from selected scientific papers using the Qualitative Reasoning framework. As a proof of concept, we apply the approach to modelling papers about cellulose hydrolysis mechanism, focusing on the causal explanations for the decreasing of hydrolytic rate. Two explanatory QR models are built to capture classical explanations for the phenomenon. Our results show that none of them provides sufficient explanation for a set of basic experimental observations described in the literature. Combining the two explanations into a third one allowed to get a new and sufficient explanation for the experimental results. In domains where numerical data are scarce and strongly related to the experimental conditions, this approach can aid assessing the conceptual validity of an explanation and support integration of knowledge from different sources.
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Affiliation(s)
- Kamal Kansou
- INRA, Biopolymères Interactions Assemblages, BP 71267, 44316, Nantes, France.
| | - Caroline Rémond
- FARE laboratory, INRA, University of Reims Champagne-Ardenne, 51100, Reims, France
| | - Gabriel Paës
- FARE laboratory, INRA, University of Reims Champagne-Ardenne, 51100, Reims, France
| | - Estelle Bonnin
- INRA, Biopolymères Interactions Assemblages, BP 71267, 44316, Nantes, France
| | - Jean Tayeb
- FARE laboratory, INRA, University of Reims Champagne-Ardenne, 51100, Reims, France
| | - Bert Bredeweg
- Informatics Institute, University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands
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16
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Badino SF, Bathke JK, Sørensen TH, Windahl MS, Jensen K, Peters GHJ, Borch K, Westh P. The influence of different linker modifications on the catalytic activity and cellulose affinity of cellobiohydrolase Cel7A from Hypocrea jecorina. Protein Eng Des Sel 2017; 30:495-501. [PMID: 28873985 DOI: 10.1093/protein/gzx036] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 07/04/2017] [Indexed: 12/13/2022] Open
Abstract
Various cellulases consist of a catalytic domain connected to a carbohydrate-binding module (CBM) by a flexible linker peptide. The linker if often strongly O-glycosylated and typically has a length of 20-50 amino acid residues. Functional roles, other than connecting the two folded domains, of the linker and its glycans, have been widely discussed, but experimental evidence remains sparse. One of the most studied cellulose degrading enzymes is the multi-domain cellobiohydrolase Cel7A from Hypocrea jecorina. Here, we designed variants of Cel7A with mutations in the linker region to elucidate the role of the linker. We found that moderate modification of the linker could result in significant changes in substrate affinity and catalytic efficacy. These changes were quite different for different linker variants. Thus, deletion of six residues near the catalytic domain had essentially no effects on enzyme function. Conversely, a substitution of four glycosylation sites near the middle of the linker reduced substrate affinity and increased maximal turnover. The observation of weaker binding provides some support of recent suggestions that linker glycans may be directly involved in substrate interactions. However, a variant with several inserted glycosylation sites near the CBM also showed lower affinity for the substrate compared to the wild-type, and we suggest that substrate interactions of the glycans depend on their exact location as well as other factors such as changes in structure and dynamics of the linker peptide.
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Affiliation(s)
- Silke Flindt Badino
- Research Unit for Functional Biomaterials, Department of Science and Environment, INM, Roskilde University, 1 Universitetsvej, Build. 28 C, DK-4000, Roskilde, Denmark
| | - Jenny Kim Bathke
- Department of Chemistry, Technical University of Denmark, Kemitorvet, Build. 207, DK-2800 Kgs. Lyngby, Denmark
| | - Trine Holst Sørensen
- Research Unit for Functional Biomaterials, Department of Science and Environment, INM, Roskilde University, 1 Universitetsvej, Build. 28 C, DK-4000, Roskilde, Denmark
| | - Michael Skovbo Windahl
- Research Unit for Functional Biomaterials, Department of Science and Environment, INM, Roskilde University, 1 Universitetsvej, Build. 28 C, DK-4000, Roskilde, Denmark
| | - Kenneth Jensen
- Novozymes A/S, Krogshøjvej 36, DK-2880, Bagsværd, Denmark
| | - Günther H J Peters
- Department of Chemistry, Technical University of Denmark, Kemitorvet, Build. 207, DK-2800 Kgs. Lyngby, Denmark
| | - Kim Borch
- Novozymes A/S, Krogshøjvej 36, DK-2880, Bagsværd, Denmark
| | - Peter Westh
- Research Unit for Functional Biomaterials, Department of Science and Environment, INM, Roskilde University, 1 Universitetsvej, Build. 28 C, DK-4000, Roskilde, Denmark
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17
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Jeoh T, Cardona MJ, Karuna N, Mudinoor AR, Nill J. Mechanistic kinetic models of enzymatic cellulose hydrolysis-A review. Biotechnol Bioeng 2017; 114:1369-1385. [PMID: 28244589 DOI: 10.1002/bit.26277] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 02/10/2017] [Accepted: 02/22/2017] [Indexed: 01/05/2023]
Abstract
Bioconversion of lignocellulose forms the basis for renewable, advanced biofuels, and bioproducts. Mechanisms of hydrolysis of cellulose by cellulases have been actively studied for nearly 70 years with significant gains in understanding of the cellulolytic enzymes. Yet, a full mechanistic understanding of the hydrolysis reaction has been elusive. We present a review to highlight new insights gained since the most recent comprehensive review of cellulose hydrolysis kinetic models by Bansal et al. (2009) Biotechnol Adv 27:833-848. Recent models have taken a two-pronged approach to tackle the challenge of modeling the complex heterogeneous reaction-an enzyme-centric modeling approach centered on the molecularity of the cellulase-cellulose interactions to examine rate limiting elementary steps and a substrate-centric modeling approach aimed at capturing the limiting property of the insoluble cellulose substrate. Collectively, modeling results suggest that at the molecular-scale, how rapidly cellulases can bind productively (complexation) and release from cellulose (decomplexation) is limiting, while the overall hydrolysis rate is largely insensitive to the catalytic rate constant. The surface area of the insoluble substrate and the degrees of polymerization of the cellulose molecules in the reaction both limit initial hydrolysis rates only. Neither enzyme-centric models nor substrate-centric models can consistently capture hydrolysis time course at extended reaction times. Thus, questions of the true reaction limiting factors at extended reaction times and the role of complexation and decomplexation in rate limitation remain unresolved. Biotechnol. Bioeng. 2017;114: 1369-1385. © 2017 Wiley Periodicals, Inc.
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Affiliation(s)
- Tina Jeoh
- Biological and Agricultural Engineering, University of California, Davis, California
| | - Maria J Cardona
- Chemical Engineering, University of California, Davis, California.,Intel Corporation, Hillsboro, Oregon
| | - Nardrapee Karuna
- Biological and Agricultural Engineering, University of California, Davis, California.,Department of Biotechnology, Faculty of Engineering and Industrial Technology, Silpakorn University, Nakhon Pathom, Thailand
| | - Akshata R Mudinoor
- Biological and Agricultural Engineering, University of California, Davis, California
| | - Jennifer Nill
- Chemical Engineering, University of California, Davis, California
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18
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Cruys-Bagger N, Alasepp K, Andersen M, Ottesen J, Borch K, Westh P. Rate of Threading a Cellulose Chain into the Binding Tunnel of a Cellulase. J Phys Chem B 2016; 120:5591-600. [DOI: 10.1021/acs.jpcb.6b01877] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Nicolaj Cruys-Bagger
- Department
of Science and Environment, Roskilde University, 1 Universitetsvej, DK-4000 Roskilde, Denmark
- Novozymes A/S, Krogshøjvej
36, DK-2880 Bagsværd, Denmark
| | - Kadri Alasepp
- Department
of Science and Environment, Roskilde University, 1 Universitetsvej, DK-4000 Roskilde, Denmark
| | - Morten Andersen
- Department
of Science and Environment, Roskilde University, 1 Universitetsvej, DK-4000 Roskilde, Denmark
| | - Johnny Ottesen
- Department
of Science and Environment, Roskilde University, 1 Universitetsvej, DK-4000 Roskilde, Denmark
| | - Kim Borch
- Novozymes A/S, Krogshøjvej
36, DK-2880 Bagsværd, Denmark
| | - Peter Westh
- Department
of Science and Environment, Roskilde University, 1 Universitetsvej, DK-4000 Roskilde, Denmark
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19
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Rosales-Calderon O, Trajano HL, Posarac D, Duff SJ. Modeling of Oxygen Delignified Wheat Straw Enzymatic Hydrolysis as a Function of Hydrolysis Time, Enzyme Concentration, and Lignin Content. Ind Biotechnol (New Rochelle N Y) 2016. [DOI: 10.1089/ind.2015.0037] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Oscar Rosales-Calderon
- Department of Chemical and Biological Engineering, University of British Columbia, Vancouver, BC, Canada
| | - Heather L. Trajano
- Department of Chemical and Biological Engineering, University of British Columbia, Vancouver, BC, Canada
| | - Dusko Posarac
- Department of Chemical and Biological Engineering, University of British Columbia, Vancouver, BC, Canada
| | - Sheldon J.B. Duff
- Department of Chemical and Biological Engineering, University of British Columbia, Vancouver, BC, Canada
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20
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Arslan B, Colpan M, Ju X, Zhang X, Kostyukova A, Abu-Lail NI. The Effects of Noncellulosic Compounds on the Nanoscale Interaction Forces Measured between Carbohydrate-Binding Module and Lignocellulosic Biomass. Biomacromolecules 2016; 17:1705-15. [PMID: 27065303 DOI: 10.1021/acs.biomac.6b00129] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The lack of fundamental understanding of the types of forces that govern how cellulose-degrading enzymes interact with cellulosic and noncellulosic components of lignocellulosic surfaces limits the design of new strategies for efficient conversion of biomass to bioethanol. In a step to improve our fundamental understanding of such interactions, nanoscale forces acting between a model cellulase-a carbohydrate-binding module (CBM) of cellobiohydrolase I (CBH I)-and a set of lignocellulosic substrates with controlled composition were measured using atomic force microscopy (AFM). The three model substrates investigated were kraft (KP), sulfite (SP), and organosolv (OPP) pulped substrates. These substrates varied in their surface lignin coverage, lignin type, and xylan and acetone extractives' content. Our results indicated that the overall adhesion forces of biomass to CBM increased linearly with surface lignin coverage with kraft lignin showing the highest forces among lignin types investigated. When the overall adhesion forces were decoupled into specific and nonspecific component forces via the Poisson statistical model, hydrophobic and Lifshitz-van der Waals (LW) forces dominated the binding forces of CBM to kraft lignin, whereas permanent dipole-dipole interactions and electrostatic forces facilitated the interactions of lignosulfonates to CBM. Xylan and acetone extractives' content increased the attractive forces between CBM and lignin-free substrates, most likely through hydrogen bonding forces. When the substrates treated differently were compared, it was found that both the differences in specific and nonspecific forces between lignin-containing and lignin-free substrates were the least for OPP. Therefore, cellulase enzymes represented by CBM would weakly bind to organosolv lignin. This will facilitate an easy enzyme recovery compared to other substrates treated with kraft or sulfite pulping. Our results also suggest that altering the surface hydrophobicity and the surface energy of lignin that facilitates the LW forces should be a priori to avoid nonproductive binding of cellulase to kraft lignin.
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Affiliation(s)
- Baran Arslan
- Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University , Pullman, Washington 99164-6515, United States
| | - Mert Colpan
- Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University , Pullman, Washington 99164-6515, United States
| | - Xiaohui Ju
- Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Bioproducts' Science and Engineering Laboratory, Washington State University , Richland, Washington 99354-1670, United States
| | - Xiao Zhang
- Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Bioproducts' Science and Engineering Laboratory, Washington State University , Richland, Washington 99354-1670, United States
| | - Alla Kostyukova
- Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University , Pullman, Washington 99164-6515, United States
| | - Nehal I Abu-Lail
- Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University , Pullman, Washington 99164-6515, United States
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21
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Eibinger M, Zahel T, Ganner T, Plank H, Nidetzky B. Cellular automata modeling depicts degradation of cellulosic material by a cellulase system with single-molecule resolution. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:56. [PMID: 26962329 PMCID: PMC4784381 DOI: 10.1186/s13068-016-0463-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 02/19/2016] [Indexed: 05/15/2023]
Abstract
BACKGROUND Enzymatic hydrolysis of cellulose involves the spatiotemporally correlated action of distinct polysaccharide chain cleaving activities confined to the surface of an insoluble substrate. Because cellulases differ in preference for attacking crystalline compared to amorphous cellulose, the spatial distribution of structural order across the cellulose surface imposes additional constraints on the dynamic interplay between the enzymes. Reconstruction of total system behavior from single-molecule activity parameters is a longstanding key goal in the field. RESULTS We have developed a stochastic, cellular automata-based modeling approach to describe degradation of cellulosic material by a cellulase system at single-molecule resolution. Substrate morphology was modeled to represent the amorphous and crystalline phases as well as the different spatial orientations of the polysaccharide chains. The enzyme system model consisted of an internally chain-cleaving endoglucanase (EG) as well as two processively acting, reducing and non-reducing chain end-cleaving cellobiohydrolases (CBHs). Substrate preference (amorphous: EG, CBH II; crystalline: CBH I) and characteristic frequencies for chain cleavage, processive movement, and dissociation were assigned from biochemical data. Once adsorbed, enzymes were allowed to reach surface-exposed substrate sites through "random-walk" lateral diffusion or processive motion. Simulations revealed that slow dissociation of processive enzymes at obstacles obstructing further movement resulted in local jamming of the cellulases, with consequent delay in the degradation of the surface area affected. Exploiting validation against evidence from atomic force microscopy imaging as a unique opportunity opened up by the modeling approach, we show that spatiotemporal characteristics of cellulose surface degradation by the system of synergizing cellulases were reproduced quantitatively at the nanometer resolution of the experimental data. This in turn gave useful prediction of the soluble sugar release rate. CONCLUSIONS Salient dynamic features of cellulose surface degradation by different cellulases acting in synergy were reproduced in simulations in good agreement with evidence from high-resolution visualization experiments. Due to the single-molecule resolution of the modeling approach, the utility of the presented model lies not only in predicting system behavior but also in elucidating inherently complex (e.g., stochastic) phenomena involved in enzymatic cellulose degradation. Thus, it creates synergy with experiment to advance the mechanistic understanding for improved application.
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Affiliation(s)
- Manuel Eibinger
- />Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, NAWI Graz, Petersgasse 12, 8010 Graz, Austria
| | - Thomas Zahel
- />Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, NAWI Graz, Petersgasse 12, 8010 Graz, Austria
| | - Thomas Ganner
- />Institute for Electron Microscopy and Nanoanalysis, Graz University of Technology, Steyrergasse 17, 8010 Graz, Austria
| | - Harald Plank
- />Institute for Electron Microscopy and Nanoanalysis, Graz University of Technology, Steyrergasse 17, 8010 Graz, Austria
- />Graz Centre for Electron Microscopy, Steyrergasse 17, 8010 Graz, Austria
| | - Bernd Nidetzky
- />Institute of Biotechnology and Biochemical Engineering, Graz University of Technology, NAWI Graz, Petersgasse 12, 8010 Graz, Austria
- />Austrian Centre of Industrial Biotechnology, Petersgasse 14, 8010 Graz, Austria
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22
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Hamid SBA, Islam MM, Das R. Cellulase biocatalysis: key influencing factors and mode of action. CELLULOSE 2015; 22:2157-2182. [DOI: 10.1007/s10570-015-0672-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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23
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Sørensen TH, Cruys-Bagger N, Borch K, Westh P. Free Energy Diagram for the Heterogeneous Enzymatic Hydrolysis of Glycosidic Bonds in Cellulose. J Biol Chem 2015; 290:22203-11. [PMID: 26183776 DOI: 10.1074/jbc.m115.659656] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Indexed: 01/25/2023] Open
Abstract
Kinetic and thermodynamic data have been analyzed according to transition state theory and a simplified reaction scheme for the enzymatic hydrolysis of insoluble cellulose. For the cellobiohydrolase Cel7A from Hypocrea jecorina (Trichoderma reesei), we were able to measure or collect relevant values for all stable and activated complexes defined by the reaction scheme and hence propose a free energy diagram for the full heterogeneous process. For other Cel7A enzymes, including variants with and without carbohydrate binding module (CBM), we obtained activation parameters for the association and dissociation of the enzyme-substrate complex. The results showed that the kinetics of enzyme-substrate association (i.e. formation of the Michaelis complex) was almost entirely entropy-controlled and that the activation entropy corresponded approximately to the loss of translational and rotational degrees of freedom of the dissolved enzyme. This implied that the transition state occurred early in the path where the enzyme has lost these degrees of freedom but not yet established extensive contact interactions in the binding tunnel. For dissociation, a similar analysis suggested that the transition state was late in the path where most enzyme-substrate contacts were broken. Activation enthalpies revealed that the rate of dissociation was far more temperature-sensitive than the rates of both association and the inner catalytic cycle. Comparisons of one- and two-domain variants showed that the CBM had no influence on the transition state for association but increased the free energy barrier for dissociation. Hence, the CBM appeared to promote the stability of the complex by delaying dissociation rather than accelerating association.
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Affiliation(s)
- Trine Holst Sørensen
- From Roskilde University, NSM, Research Unit for Functional Biomaterials, 1 Universitetsvej, Building 28, DK-4000 Roskilde, Denmark and
| | - Nicolaj Cruys-Bagger
- From Roskilde University, NSM, Research Unit for Functional Biomaterials, 1 Universitetsvej, Building 28, DK-4000 Roskilde, Denmark and
| | - Kim Borch
- Novozymes A/S, Krogshøjvej 36, DK-2880 Bagsværd, Denmark
| | - Peter Westh
- From Roskilde University, NSM, Research Unit for Functional Biomaterials, 1 Universitetsvej, Building 28, DK-4000 Roskilde, Denmark and
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24
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Michna A, Adamczyk Z, Batys P. Mapping single macromolecule chains using the colloid deposition method: PDADMAC on mica. J Colloid Interface Sci 2015; 450:82-90. [PMID: 25801136 DOI: 10.1016/j.jcis.2015.02.057] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 02/20/2015] [Accepted: 02/20/2015] [Indexed: 10/23/2022]
Abstract
Monolayers of the cationic polyelectrolyte poly(diallyldimethylammonium chloride) (PDADMAC) on mica were thoroughly characterized using the streaming potential and the colloid deposition methods. Initially, the stability of the monolayers was determined by performing desorption experiments carried out under diffusion-controlled regime. It was shown that the desorption of the polyelectrolyte at the ionic strength range 0.01-0.15 M is negligible over the time of 20 h. The structure of PDADMAC monolayers and orientation of molecules were evaluated using the colloid deposition measurements involving negatively charged polystyrene latex microspheres, 820 nm in diameter. The functional relationships between the polyelectrolyte coverage and latex coverage deposited within 20 h were acquired by direct optical microscope. In this way the influence of ionic strength varied in the range 0.15-0.01 M on the molecule orientation in monolayers was determined. It was shown that for ionic strength of 0.15 M nearly one to one mapping of polyelectrolyte chains by colloid particles can be achieved for PDADMAC coverage below 0.1%. In this way, because of a considerable surface area ratio between the macromolecule and the colloid particle, an enhancement factor of 10(3) can be attained. This behavior was quantitatively interpreted in terms of the random site adsorption model whereas the classical mean-field theory proved inadequate. On the other hand, for lower ionic strength, it was confirmed that an irreversible immobilization of latex particles can only occur at a few closely spaced PDADMAC chains. It was shown that these experimental results were consistent with the side-on adsorption mechanisms of PDADMAC at mica for the above ionic strength.
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Affiliation(s)
- Aneta Michna
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Niezapominajek 8, 30-239 Cracow, Poland.
| | - Zbigniew Adamczyk
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Niezapominajek 8, 30-239 Cracow, Poland.
| | - Piotr Batys
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Niezapominajek 8, 30-239 Cracow, Poland.
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25
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Abstract
PURPOSE We developed an in vitro model-blink cell that reproduces the mechanism of in vivo fouling of soft contact lenses. In the model-blink cell, model tear lipid directly contacts the lens surface after forced aqueous rupture, mirroring the pre-lens tear-film breakup during interblink. METHODS Soft contact lenses are attached to a Teflon holder and immersed in artificial tear solution with protein, salts, and mucins. Artificial tear-lipid solution is spread over the air/tear interface as a duplex lipid layer. The aqueous tear film is periodically ruptured and reformed by withdrawing and reinjecting tear solution into the cell, mimicking the blink-rupture process. Fouled deposits appear on the lenses after cycling, and their compositions and spatial distributions are subsequently analyzed by optical microscopy, laser ablation electrospray ionization mass spectrometry, and two-photon fluorescence confocal scanning laser microscopy. RESULTS Discrete deposit (white) spots with an average size of 20 to 300 μm are observed on the studied lenses, confirming what is seen in vivo and validating the in vitro model-blink cell. Targeted lipids (cholesterol) and proteins (albumin from bovine serum) are identified in the discrete surface deposits. Both lipid and protein occur simultaneously in the surface deposits and overlap with the white spots observed by optical microscopy. Additionally, lipid and protein penetrate into the bulk of tested silicone-hydrogel lenses, likely attributed to the bicontinuous microstructure of oleophilic silicone and hydrophilic polymer phases of the lens. CONCLUSIONS In vitro spoilation of soft contact lenses is successfully achieved by the model-blink cell confirming the tear rupture/deposition mechanism of lens fouling. The model-blink cell provides a reliable laboratory tool for screening new antifouling lens materials, surface coatings, and care solutions.
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26
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Wang C, Venditti RA, Zhang K. Tailor-made functional surfaces based on cellulose-derived materials. Appl Microbiol Biotechnol 2015; 99:5791-9. [PMID: 26084889 DOI: 10.1007/s00253-015-6722-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2015] [Revised: 05/21/2015] [Accepted: 05/25/2015] [Indexed: 01/30/2023]
Abstract
As one of the most abundant natural materials in nature, cellulose has revealed enormous potential for the construction of functional materials thanks to its sustainability, non-toxicity, biocompatibility, and biodegradability. Among many fascinating applications, functional surfaces based on cellulose-derived materials have attracted increasing interest recently, as platforms for diagnostics, sensoring, robust catalysis, water treatment, ultrafiltration, and anti-microbial surfaces. This mini-review attempts to cover the general methodology for the fabrication of functional cellulose surface and a few popular applications including bioactive and non-adhesive (i.e., anti-fouling and anti-microbial) surfaces.
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Affiliation(s)
- Chao Wang
- Department of Forest Biomaterials, North Carolina State University, Raleigh, NC, 27695, USA
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27
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Machado DL, Moreira Neto J, da Cruz Pradella JG, Bonomi A, Rabelo SC, da Costa AC. Adsorption characteristics of cellulase and β-glucosidase on Avicel, pretreated sugarcane bagasse, and lignin. Biotechnol Appl Biochem 2015; 62:681-9. [DOI: 10.1002/bab.1307] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 10/10/2014] [Indexed: 01/27/2023]
Affiliation(s)
- Daniele Longo Machado
- Laboratory of Fermentative and Enzymatic Process Engineering; School of Chemical Engineering, University of Campinas; Campinas SP Brazil
| | - João Moreira Neto
- Laboratory of Fermentative and Enzymatic Process Engineering; School of Chemical Engineering, University of Campinas; Campinas SP Brazil
| | | | - Antonio Bonomi
- Laboratory of Fermentative and Enzymatic Process Engineering; School of Chemical Engineering, University of Campinas; Campinas SP Brazil
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE)--CTBE/CNPEM; Campinas SP Brazil
| | - Sarita Cândida Rabelo
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE)--CTBE/CNPEM; Campinas SP Brazil
| | - Aline Carvalho da Costa
- Laboratory of Fermentative and Enzymatic Process Engineering; School of Chemical Engineering, University of Campinas; Campinas SP Brazil
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28
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Influence of ionic strength on poly(diallyldimethylammonium chloride) macromolecule conformations in electrolyte solutions. J Colloid Interface Sci 2014; 435:182-90. [DOI: 10.1016/j.jcis.2014.07.037] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 07/24/2014] [Accepted: 07/25/2014] [Indexed: 02/02/2023]
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Kari J, Olsen J, Borch K, Cruys-Bagger N, Jensen K, Westh P. Kinetics of cellobiohydrolase (Cel7A) variants with lowered substrate affinity. J Biol Chem 2014; 289:32459-68. [PMID: 25271162 DOI: 10.1074/jbc.m114.604264] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cellobiohydrolases are exo-active glycosyl hydrolases that processively convert cellulose to soluble sugars, typically cellobiose. They effectively break down crystalline cellulose and make up a major component in industrial enzyme mixtures used for deconstruction of lignocellulosic biomass. Identification of the rate-limiting step for cellobiohydrolases remains controversial, and recent reports have alternately suggested either association (on-rate) or dissociation (off-rate) as the overall bottleneck. Obviously, this uncertainty hampers both fundamental mechanistic understanding and rational design of enzymes with improved industrial applicability. To elucidate the role of on- and off-rates, respectively, on the overall kinetics, we have expressed a variant in which a tryptophan residue (Trp-38) in the middle of the active tunnel has been replaced with an alanine. This mutation weakens complex formation, and the population of substrate-bound W38A was only about half of the wild type. Nevertheless, the maximal, steady-state rate was twice as high for the variant enzyme. It is argued that these opposite effects on binding and activity can be reconciled if the rate-limiting step is after the catalysis (i.e. in the dissociation process).
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Affiliation(s)
- Jeppe Kari
- From Department of Science, Systems and Models, Research Unit for Functional Biomaterials, Roskilde University, 1 Universitetsvej, DK-4000 Roskilde, Denmark and
| | - Johan Olsen
- From Department of Science, Systems and Models, Research Unit for Functional Biomaterials, Roskilde University, 1 Universitetsvej, DK-4000 Roskilde, Denmark and
| | - Kim Borch
- Novozymes A/S, Krogshøjvej 36, Bagsværd DK-2880, Denmark
| | - Nicolaj Cruys-Bagger
- From Department of Science, Systems and Models, Research Unit for Functional Biomaterials, Roskilde University, 1 Universitetsvej, DK-4000 Roskilde, Denmark and
| | - Kenneth Jensen
- Novozymes A/S, Krogshøjvej 36, Bagsværd DK-2880, Denmark
| | - Peter Westh
- From Department of Science, Systems and Models, Research Unit for Functional Biomaterials, Roskilde University, 1 Universitetsvej, DK-4000 Roskilde, Denmark and
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30
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Michna A, Adamczyk Z, Kubiak K, Jamroży K. Formation of PDADMAC monolayers evaluated in situ by QCM and streaming potential measurements. J Colloid Interface Sci 2014; 428:170-7. [DOI: 10.1016/j.jcis.2014.04.013] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Revised: 04/03/2014] [Accepted: 04/05/2014] [Indexed: 12/26/2022]
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31
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A graphene screen-printed carbon electrode for real-time measurements of unoccupied active sites in a cellulase. Anal Biochem 2014; 447:162-8. [DOI: 10.1016/j.ab.2013.11.024] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 11/13/2013] [Accepted: 11/22/2013] [Indexed: 11/17/2022]
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32
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Cruys-Bagger N, Tatsumi H, Ren GR, Borch K, Westh P. Transient kinetics and rate-limiting steps for the processive cellobiohydrolase Cel7A: effects of substrate structure and carbohydrate binding domain. Biochemistry 2013; 52:8938-48. [PMID: 24228828 DOI: 10.1021/bi401210n] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cellobiohydrolases are exoacting, processive enzymes that effectively hydrolyze crystalline cellulose. They have attracted considerable interest because of their role in both natural carbon cycling and industrial enzyme cocktails used for the deconstruction of cellulosic biomass, but many mechanistic and regulatory aspects of their heterogeneous catalysis remain poorly understood. Here, we address this by applying a deterministic model to real-time kinetic data with high temporal resolution. We used two variants of the cellobiohydrolase Cel7A from Hypocrea jecorina , and three types of cellulose as substrate. Analysis of the pre-steady-state regime allowed delineation rate constants for both fast and slow steps in the enzymatic cycle and assessment of how these constants influenced the rate of hydrolysis at quasi-steady state. Processive movement on the cellulose strand advanced with characteristic times of 0.15-0.7 s per step at 25 °C, and the rate was highest on amorphous substrate. The cellulose binding module was found to raise this rate on crystalline, but not on amorphous, substrate. The rapid processive movement signified high intrinsic reactivity, but this parameter had marginal influence on the steady-state rate. This was because dissociation and association were slower and, hence, rate limiting. Specifically, the dissociation from the strand was found to occur with characteristic times of 45-100 s. This meant that dissociation was the bottleneck, except at very low substrate loads (0.5-1 g/L), where association became slower.
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Affiliation(s)
- Nicolaj Cruys-Bagger
- Research Unit for Functional Biomaterials, NSM, Roskilde University , Universitetsvej 1, DK-4000 Roskilde, Denmark
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33
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Shang BZ, Chang R, Chu JW. Systems-level modeling with molecular resolution elucidates the rate-limiting mechanisms of cellulose decomposition by cellobiohydrolases. J Biol Chem 2013; 288:29081-9. [PMID: 23950182 DOI: 10.1074/jbc.m113.497412] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Interprotein and enzyme-substrate couplings in interfacial biocatalysis induce spatial correlations beyond the capabilities of classical mass-action principles in modeling reaction kinetics. To understand the impact of spatial constraints on enzyme kinetics, we developed a computational scheme to simulate the reaction network of enzymes with the structures of individual proteins and substrate molecules explicitly resolved in the three-dimensional space. This methodology was applied to elucidate the rate-limiting mechanisms of crystalline cellulose decomposition by cellobiohydrolases. We illustrate that the primary bottlenecks are slow complexation of glucan chains into the enzyme active site and excessive enzyme jamming along the crowded substrate. Jamming could be alleviated by increasing the decomplexation rate constant but at the expense of reduced processivity. We demonstrate that enhancing the apparent reaction rate required a subtle balance between accelerating the complexation driving force and simultaneously avoiding enzyme jamming. Via a spatiotemporal systems analysis, we developed a unified mechanistic framework that delineates the experimental conditions under which different sets of rate-limiting behaviors emerge. We found that optimization of the complexation-exchange kinetics is critical for overcoming the barriers imposed by interfacial confinement and accelerating the apparent rate of enzymatic cellulose decomposition.
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Affiliation(s)
- Barry Z Shang
- From the Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720
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34
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Teugjas H, Väljamäe P. Product inhibition of cellulases studied with 14C-labeled cellulose substrates. BIOTECHNOLOGY FOR BIOFUELS 2013; 6:104. [PMID: 23883520 PMCID: PMC3726336 DOI: 10.1186/1754-6834-6-104] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Accepted: 07/11/2013] [Indexed: 05/02/2023]
Abstract
BACKGROUND As a green alternative for the production of transportation fuels, the enzymatic hydrolysis of lignocellulose and subsequent fermentation to ethanol are being intensively researched. To be economically feasible, the hydrolysis of lignocellulose must be conducted at a high concentration of solids, which results in high concentrations of hydrolysis end-products, cellobiose and glucose, making the relief of product inhibition of cellulases a major challenge in the process. However, little quantitative information on the product inhibition of individual cellulases acting on cellulose substrates is available because it is experimentally difficult to assess the hydrolysis of the heterogeneous polymeric substrate in the high background of added products. RESULTS The cellobiose and glucose inhibition of thermostable cellulases from Acremonium thermophilum, Thermoascus aurantiacus, and Chaetomium thermophilum acting on uniformly 14C-labeled bacterial cellulose and its derivatives, 14C-bacterial microcrystalline cellulose and 14C-amorphous cellulose, was studied. Cellulases from Trichoderma reesei were used for comparison. The enzymes most sensitive to cellobiose inhibition were glycoside hydrolase (GH) family 7 cellobiohydrolases (CBHs), followed by family 6 CBHs and endoglucanases (EGs). The strength of glucose inhibition followed the same order. The product inhibition of all enzymes was relieved at higher temperatures. The inhibition strength measured for GH7 CBHs with low molecular-weight model substrates did not correlate with that measured with 14C-cellulose substrates. CONCLUSIONS GH7 CBHs are the primary targets for product inhibition of the synergistic hydrolysis of cellulose. The inhibition must be studied on cellulose substrates instead of on low molecular-weight model substrates when selecting enzymes for lignocellulose hydrolysis. The advantages of using higher temperatures are an increase in the catalytic efficiency of enzymes and the relief of product inhibition.
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Affiliation(s)
- Hele Teugjas
- Institute of Molecular and Cell Biology, University of Tartu, Riia 23b – 202, Tartu 51010, Estonia
| | - Priit Väljamäe
- Institute of Molecular and Cell Biology, University of Tartu, Riia 23b – 202, Tartu 51010, Estonia
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35
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Martín-Sampedro R, Rahikainen JL, Johansson LS, Marjamaa K, Laine J, Kruus K, Rojas OJ. Preferential Adsorption and Activity of Monocomponent Cellulases on Lignocellulose Thin Films with Varying Lignin Content. Biomacromolecules 2013; 14:1231-9. [DOI: 10.1021/bm400230s] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Raquel Martín-Sampedro
- Department of Forest Products
Technology, School of Chemical Technology, Aalto University, FI-00076 Aalto, Espoo, Finland
| | - Jenni L. Rahikainen
- VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044 VTT, Espoo,
Finland
| | - Leena-Sisko Johansson
- Department of Forest Products
Technology, School of Chemical Technology, Aalto University, FI-00076 Aalto, Espoo, Finland
| | - Kaisa Marjamaa
- VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044 VTT, Espoo,
Finland
| | - Janne Laine
- Department of Forest Products
Technology, School of Chemical Technology, Aalto University, FI-00076 Aalto, Espoo, Finland
| | - Kristiina Kruus
- VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044 VTT, Espoo,
Finland
| | - Orlando J. Rojas
- Department of Forest Products
Technology, School of Chemical Technology, Aalto University, FI-00076 Aalto, Espoo, Finland
- Departments of Forest
and Biomaterials
and Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695, United
States
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Maurer S, Brady N, Fajardo N, Radke C. Surface kinetics for cooperative fungal cellulase digestion of cellulose from quartz crystal microgravimetry. J Colloid Interface Sci 2013; 394:498-508. [DOI: 10.1016/j.jcis.2012.12.022] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Revised: 12/07/2012] [Accepted: 12/08/2012] [Indexed: 10/27/2022]
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37
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Maurer SA, Bedbrook CN, Radke CJ. Competitive sorption kinetics of inhibited endo- and exoglucanases on a model cellulose substrate. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:14598-608. [PMID: 22966968 DOI: 10.1021/la3024524] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
For the first time, the competitive adsorption of inhibited cellobiohydrolase I (Cel7A, an exoglucanase) and endoglucanase I (Cel7B) from T. longibrachiatum is studied on cellulose. Using quartz crystal microgravimetry (QCM), sorption histories are measured for individual types of cellulases and their mixtures adsorbing to and desorbing from a model cellulose surface. We find that Cel7A has a higher adsorptive affinity for cellulose than does Cel7B. The adsorption of both cellulases becomes irreversible on time scales of 30-60 min, which are much shorter than those typically used for industrial cellulose hydrolysis. A multicomponent Langmuir kinetic model including first-order irreversible binding is proposed. Although adsorption and desorption rate constants differ between the two enzymes, the rate at which each surface enzyme irreversibly binds is identical. Because of the higher affinity of Cel7A for the cellulose surface, when Cel7A and Cel7B compete for surface sites, a significantly higher bulk concentration of Cel7B is required to achieve comparable surface enzyme concentrations. Because cellulose deconstruction benefits significantly from the cooperative activity of endoglucanases and cellobiohydrolases on the cellulose surface, accounting for competitive adsorption is crucial to developing effective cellulase mixtures.
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Affiliation(s)
- Samuel A Maurer
- Department of Chemical and Biomolecular Engineering, University of California-Berkeley, Berkeley, California 94720-1462, USA
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