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Chen H, Jiang B, Zou C, Lou Z, Song J, Wu W, Jin Y. Exploring how lignin structure influences the interaction between carbohydrate-binding module and lignin using AFM. Int J Biol Macromol 2023; 232:123313. [PMID: 36682668 DOI: 10.1016/j.ijbiomac.2023.123313] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 12/23/2022] [Accepted: 01/13/2023] [Indexed: 01/22/2023]
Abstract
Nonproductive adsorption of cellulase onto the residual lignin in substrate seriously hinders the enzymatic hydrolysis. To understand how lignin structure affects lignin-cellulase interaction, the carbohydrate-binding module (CBM) functionalized atomic force microscope tip was used to measure CBM-lignin interaction by single-molecule dynamic force spectroscopy in this work. The results showed that sulfonated lignin (SL) has the greatest adhesion force to CBM (4.74 nN), while those of masson pine milled wood lignin (MWL), poplar MWL and herbaceous MWLs were 2.85, 1.03 and 0.27-0.61 nN, respectively. It provides direct quantitative evidence for the significance of lignin structure on lignin-cellulase interaction. The CBM-MWLs interaction decreased sharply to 0.054-0.083 nN while SL was added, indicating the primary mechanism of SL promoting lignocellulose hydrolysis was significantly reducing the nonproductive adsorption of substrate lignin on cellulase. Finally, the "competitive adsorption" mechanism was proposed to interpret why SL effectively promotes the enzymatic hydrolysis of lignin-containing substrates.
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Affiliation(s)
- Hui Chen
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Light Industry and Food Engineering, Nanjing Forestry University, Nanjing 210037, China; Joint International Research Lab of Lignocellulosic Functional Materials, International Innovation Center for Forest Chemicals and Materials, Nanjing Forestry University, Nanjing 210037, China
| | - Bo Jiang
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Light Industry and Food Engineering, Nanjing Forestry University, Nanjing 210037, China; Joint International Research Lab of Lignocellulosic Functional Materials, International Innovation Center for Forest Chemicals and Materials, Nanjing Forestry University, Nanjing 210037, China
| | - Chunyang Zou
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Light Industry and Food Engineering, Nanjing Forestry University, Nanjing 210037, China
| | - Zhichao Lou
- Joint International Research Lab of Lignocellulosic Functional Materials, International Innovation Center for Forest Chemicals and Materials, Nanjing Forestry University, Nanjing 210037, China
| | - Junlong Song
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Light Industry and Food Engineering, Nanjing Forestry University, Nanjing 210037, China; Joint International Research Lab of Lignocellulosic Functional Materials, International Innovation Center for Forest Chemicals and Materials, Nanjing Forestry University, Nanjing 210037, China
| | - Wenjuan Wu
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Light Industry and Food Engineering, Nanjing Forestry University, Nanjing 210037, China.
| | - Yongcan Jin
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Light Industry and Food Engineering, Nanjing Forestry University, Nanjing 210037, China; Joint International Research Lab of Lignocellulosic Functional Materials, International Innovation Center for Forest Chemicals and Materials, Nanjing Forestry University, Nanjing 210037, China.
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2
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Cellulose-degrading enzymes: key players in biorefinery development. Biologia (Bratisl) 2022. [DOI: 10.1007/s11756-022-01274-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Acoustic force spectroscopy reveals subtle differences in cellulose unbinding behavior of carbohydrate-binding modules. Proc Natl Acad Sci U S A 2022; 119:e2117467119. [PMID: 36215467 PMCID: PMC9586272 DOI: 10.1073/pnas.2117467119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Protein adsorption to solid carbohydrate interfaces is critical to many biological processes, particularly in biomass deconstruction. To engineer more-efficient enzymes for biomass deconstruction into sugars, it is necessary to characterize the complex protein-carbohydrate interfacial interactions. A carbohydrate-binding module (CBM) is often associated with microbial surface-tethered cellulosomes or secreted cellulase enzymes to enhance substrate accessibility. However, it is not well known how CBMs recognize, bind, and dissociate from polysaccharides to facilitate efficient cellulolytic activity, due to the lack of mechanistic understanding and a suitable toolkit to study CBM-substrate interactions. Our work outlines a general approach to study the unbinding behavior of CBMs from polysaccharide surfaces using a highly multiplexed single-molecule force spectroscopy assay. Here, we apply acoustic force spectroscopy (AFS) to probe a Clostridium thermocellum cellulosomal scaffoldin protein (CBM3a) and measure its dissociation from nanocellulose surfaces at physiologically relevant, low force loading rates. An automated microfluidic setup and method for uniform deposition of insoluble polysaccharides on the AFS chip surfaces are demonstrated. The rupture forces of wild-type CBM3a, and its Y67A mutant, unbinding from nanocellulose surfaces suggests distinct multimodal CBM binding conformations, with structural mechanisms further explored using molecular dynamics simulations. Applying classical dynamic force spectroscopy theory, the single-molecule unbinding rate at zero force is extrapolated and found to agree with bulk equilibrium unbinding rates estimated independently using quartz crystal microbalance with dissipation monitoring. However, our results also highlight critical limitations of applying classical theory to explain the highly multivalent binding interactions for cellulose-CBM bond rupture forces exceeding 15 pN.
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Liu Y, Wang P, Tian J, Seidi F, Guo J, Zhu W, Xiao H, Song J. Carbohydrate-Binding Modules of Potential Resources: Occurrence in Nature, Function, and Application in Fiber Recognition and Treatment. Polymers (Basel) 2022; 14:polym14091806. [PMID: 35566977 PMCID: PMC9100146 DOI: 10.3390/polym14091806] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 04/21/2022] [Accepted: 04/24/2022] [Indexed: 02/04/2023] Open
Abstract
Great interests have recently been aroused in the independent associative domain of glycoside hydrolases that utilize insoluble polysaccharides-carbohydrate-binding module (CBM), which responds to binding while the catalytic domain reacts with the substrate. In this mini-review, we first provide a brief introduction on CBM and its subtypes including the classifications, potential sources, structures, and functions. Afterward, the applications of CBMs in substrate recognition based on different types of CBMs have been reviewed. Additionally, the progress of CBMs in paper industry as a new type of environmentally friendly auxiliary agent for fiber treatment is summarized. At last, other applications of CBMs and the future outlook have prospected. Due to the specificity in substrate recognition and diversity in structures, CBM can be a prosperous and promising ‘tool’ for wood and fiber processing in the future.
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Affiliation(s)
- Yena Liu
- International Innovation Center for Forest Chemicals and Materials and Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, China; (Y.L.); (P.W.); (J.T.); (F.S.); (J.G.); (W.Z.)
| | - Peipei Wang
- International Innovation Center for Forest Chemicals and Materials and Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, China; (Y.L.); (P.W.); (J.T.); (F.S.); (J.G.); (W.Z.)
| | - Jing Tian
- International Innovation Center for Forest Chemicals and Materials and Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, China; (Y.L.); (P.W.); (J.T.); (F.S.); (J.G.); (W.Z.)
| | - Farzad Seidi
- International Innovation Center for Forest Chemicals and Materials and Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, China; (Y.L.); (P.W.); (J.T.); (F.S.); (J.G.); (W.Z.)
| | - Jiaqi Guo
- International Innovation Center for Forest Chemicals and Materials and Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, China; (Y.L.); (P.W.); (J.T.); (F.S.); (J.G.); (W.Z.)
| | - Wenyuan Zhu
- International Innovation Center for Forest Chemicals and Materials and Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, China; (Y.L.); (P.W.); (J.T.); (F.S.); (J.G.); (W.Z.)
| | - Huining Xiao
- Department of Chemical Engineering, University of New Brunswick, Fredericton, NB E3B 5A3, Canada;
| | - Junlong Song
- International Innovation Center for Forest Chemicals and Materials and Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing 210037, China; (Y.L.); (P.W.); (J.T.); (F.S.); (J.G.); (W.Z.)
- Correspondence: ; Tel.: +86-25-8542-8163; Fax: +86-25-8542-8689
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Wang Z, Fan C, Zheng X, Jin Z, Bei K, Zhao M, Kong H. Roles of Surfactants in Oriented Immobilization of Cellulase on Nanocarriers and Multiphase Hydrolysis System. Front Chem 2022; 10:884398. [PMID: 35402378 PMCID: PMC8983819 DOI: 10.3389/fchem.2022.884398] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 03/09/2022] [Indexed: 11/16/2022] Open
Abstract
Surfactants, especially non-ionic surfactants, play an important role in the preparation of nanocarriers and can also promote the enzymatic hydrolysis of lignocellulose. A broad overview of the current status of surfactants on the immobilization of cellulase is provided in this review. In addition, the restricting factors in cellulase immobilization in the complex multiphase hydrolysis system are discussed, including the carrier structure characteristics, solid-solid contact obstacles, external diffusion resistance, limited recycling frequency, and nonproductive combination of enzyme active centers. Furthermore, promising prospects of cellulase-oriented immobilization are proposed, including the hydrophilic-hydrophobic interaction of surfactants and cellulase in the oil-water reaction system, the reversed micelle system of surfactants, and the possible oriented immobilization mechanism.
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Affiliation(s)
- Zhiquan Wang
- School of Life and Environmental Science, Wenzhou University, Wenzhou, China
- State and Local Joint Engineering Research Center for Ecological Treatment Technology of Urban Water Pollution, Wenzhou, China
- Zhejiang Provincial Key Lab for Water Environment and Marine Biological Resources Protection, Wenzhou, China
| | - Chunzhen Fan
- School of Life and Environmental Science, Wenzhou University, Wenzhou, China
- State and Local Joint Engineering Research Center for Ecological Treatment Technology of Urban Water Pollution, Wenzhou, China
- Zhejiang Provincial Key Lab for Water Environment and Marine Biological Resources Protection, Wenzhou, China
| | - Xiangyong Zheng
- School of Life and Environmental Science, Wenzhou University, Wenzhou, China
- State and Local Joint Engineering Research Center for Ecological Treatment Technology of Urban Water Pollution, Wenzhou, China
- Zhejiang Provincial Key Lab for Water Environment and Marine Biological Resources Protection, Wenzhou, China
| | - Zhan Jin
- School of Life and Environmental Science, Wenzhou University, Wenzhou, China
- State and Local Joint Engineering Research Center for Ecological Treatment Technology of Urban Water Pollution, Wenzhou, China
- Zhejiang Provincial Key Lab for Water Environment and Marine Biological Resources Protection, Wenzhou, China
| | - Ke Bei
- School of Life and Environmental Science, Wenzhou University, Wenzhou, China
- State and Local Joint Engineering Research Center for Ecological Treatment Technology of Urban Water Pollution, Wenzhou, China
- Zhejiang Provincial Key Lab for Water Environment and Marine Biological Resources Protection, Wenzhou, China
| | - Min Zhao
- School of Life and Environmental Science, Wenzhou University, Wenzhou, China
- State and Local Joint Engineering Research Center for Ecological Treatment Technology of Urban Water Pollution, Wenzhou, China
- Zhejiang Provincial Key Lab for Water Environment and Marine Biological Resources Protection, Wenzhou, China
| | - Hainan Kong
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai, China
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Yuan Y, Jiang B, Chen H, Wu W, Wu S, Jin Y, Xiao H. Recent advances in understanding the effects of lignin structural characteristics on enzymatic hydrolysis. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:205. [PMID: 34670604 PMCID: PMC8527784 DOI: 10.1186/s13068-021-02054-1] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 10/10/2021] [Indexed: 05/19/2023]
Abstract
Enzymatic hydrolysis of lignocellulose for bioethanol production shows a great potential to remit the rapid consumption of fossil fuels, given the fact that lignocellulose feedstocks are abundant, cost-efficient, and renewable. Lignin results in low enzymatic saccharification by forming the steric hindrance, non-productive adsorption of cellulase onto lignin, and deactivating the cellulase. In general, the non-productive binding of cellulase on lignin is widely known as the major cause for inhibiting the enzymatic hydrolysis. Pretreatment is an effective way to remove lignin and improve the enzymatic digestibility of lignocellulose. Along with removing lignin, the pretreatment can modify the lignin structure, which significantly affects the non-productive adsorption of cellulase onto lignin. To relieve the inhibitory effect of lignin on enzymatic hydrolysis, enormous efforts have been made to elucidate the correlation of lignin structure with lignin-enzyme interactions but with different views. In addition, contrary to the traditional belief that lignin inhibits enzymatic hydrolysis, in recent years, the addition of water-soluble lignin such as lignosulfonate or low molecular-weight lignin exerts a positive effect on enzymatic hydrolysis, which gives a new insight into the lignin-enzyme interactions. For throwing light on their structure-interaction relationship during enzymatic hydrolysis, the effect of residual lignin in substrate and introduced lignin in hydrolysate on enzymatic hydrolysis are critically reviewed, aiming at realizing the targeted regulation of lignin structure for improving the saccharification of lignocellulose. The review is also focused on exploring the lignin-enzyme interactions to mitigate the negative impact of lignin and reducing the cost of enzymatic hydrolysis of lignocellulose.
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Affiliation(s)
- Yufeng Yuan
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing, 210037, China
| | - Bo Jiang
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing, 210037, China
| | - Hui Chen
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing, 210037, China
| | - Wenjuan Wu
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing, 210037, China
| | - Shufang Wu
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing, 210037, China
| | - Yongcan Jin
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, Nanjing Forestry University, Nanjing, 210037, China.
- Laboratory of Wood Chemistry, Nanjing Forestry University, 159 Longpan Rd, Nanjing, 210037, China.
| | - Huining Xiao
- Department of Chemical Engineering, University of New Brunswick, Fredericton, NB, E3B 11 5A3, Canada
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7
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Zhao X, Meng X, Ragauskas AJ, Lai C, Ling Z, Huang C, Yong Q. Unlocking the secret of lignin-enzyme interactions: Recent advances in developing state-of-the-art analytical techniques. Biotechnol Adv 2021; 54:107830. [PMID: 34480987 DOI: 10.1016/j.biotechadv.2021.107830] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 08/07/2021] [Accepted: 08/29/2021] [Indexed: 02/08/2023]
Abstract
Bioconversion of renewable lignocellulosics to produce liquid fuels and chemicals is one of the most effective ways to solve the problem of fossil resource shortage, energy security, and environmental challenges. Among the many biorefinery pathways, hydrolysis of lignocellulosics to fermentable monosaccharides by cellulase is arguably the most critical step of lignocellulose bioconversion. In the process of enzymatic hydrolysis, the direct physical contact between enzymes and cellulose is an essential prerequisite for the hydrolysis to occur. However, lignin is considered one of the most recalcitrant factors hindering the accessibility of cellulose by binding to cellulase unproductively, which reduces the saccharification rate and yield of sugars. This results in high costs for the saccharification of carbohydrates. The various interactions between enzymes and lignin have been explored from different perspectives in literature, and a basic lignin inhibition mechanism has been proposed. However, the exact interaction between lignin and enzyme as well as the recently reported promotion of some types of lignin on enzymatic hydrolysis is still unclear at the molecular level. Multiple analytical techniques have been developed, and fully unlocking the secret of lignin-enzyme interactions would require a continuous improvement of the currently available analytical techniques. This review summarizes the current commonly used advanced research analytical techniques for investigating the interaction between lignin and enzyme, including quartz crystal microbalance with dissipation (QCM-D), surface plasmon resonance (SPR), attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, atomic force microscopy (AFM), nuclear magnetic resonance (NMR) spectroscopy, fluorescence spectroscopy (FLS), and molecular dynamics (MD) simulations. Interdisciplinary integration of these analytical methods is pursued to provide new insight into the interactions between lignin and enzymes. This review will serve as a resource for future research seeking to develop new methodologies for a better understanding of the basic mechanism of lignin-enzyme binding during the critical hydrolysis process.
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Affiliation(s)
- Xiaoxue Zhao
- Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Department of Bioengineering, Nanjing Forestry University, Nanjing 210037, China
| | - Xianzhi Meng
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996, USA
| | - Arthur J Ragauskas
- Department of Chemical and Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996, USA; Center for Renewable Carbon, Department of Forestry, Wildlife and Fisheries, University of Tennessee, Knoxville, TN 37996, USA; Joint Institute for Biological Sciences, Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Chenhuan Lai
- Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Department of Bioengineering, Nanjing Forestry University, Nanjing 210037, China
| | - Zhe Ling
- Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Department of Bioengineering, Nanjing Forestry University, Nanjing 210037, China
| | - Caoxing Huang
- Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Department of Bioengineering, Nanjing Forestry University, Nanjing 210037, China.
| | - Qiang Yong
- Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, Department of Bioengineering, Nanjing Forestry University, Nanjing 210037, China.
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NMR Analysis on Molecular Interaction of Lignin with Amino Acid Residues of Carbohydrate-Binding Module from Trichoderma reesei Cel7A. Sci Rep 2019; 9:1977. [PMID: 30760856 PMCID: PMC6374431 DOI: 10.1038/s41598-018-38410-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 12/12/2018] [Indexed: 12/20/2022] Open
Abstract
Lignocellulosic biomass is anticipated to serve as a platform for green chemicals and fuels. Nonproductive binding of lignin to cellulolytic enzymes should be avoided for conversion of lignocellulose through enzymatic saccharification. Although carbohydrate-binding modules (CBMs) of cellulolytic enzymes strongly bind to lignin, the adsorption mechanism at molecular level is still unclear. Here, we report NMR-based analyses of binding sites on CBM1 of cellobiohydrolase I (Cel7A) from a hyper-cellulase-producing fungus, Trichoderma reesei, with cellohexaose and lignins from Japanese cedar (C-MWL) and Eucalyptus globulus (E-MWL). A method was established to obtain properly folded TrCBM1. Only TrCBM1 that was expressed in freshly transformed E. coli had intact conformation. Chemical shift perturbation analyses revealed that TrCBM1 adsorbed cellohexaose in highly specific manner via two subsites, flat plane surface and cleft, which were located on the opposite side of the protein surface. Importantly, MWLs were adsorbed at multiple binding sites, including the subsites, having higher affinity than cellohexaose. G6 and Q7 were involved in lignin binding on the flat plane surface of TrCBM1, while cellohexaose preferentially interacted with N29 and Q34. TrCBM1 used much larger surface area to bind with C-MWL than E-MWL, indicating the mechanisms of adsorption toward hardwood and softwood lignins are different.
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Lu X, Feng X, Li X, Zhao J. Binding and hydrolysis properties of engineered cellobiohydrolases and endoglucanases. BIORESOURCE TECHNOLOGY 2018; 267:235-241. [PMID: 30025319 DOI: 10.1016/j.biortech.2018.06.047] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2018] [Revised: 06/14/2018] [Accepted: 06/17/2018] [Indexed: 05/03/2023]
Abstract
Because cellulase was the main enzyme used in bioconversion of lignocellulose, it was a valid way to reduce the hydrolysis cost by increasing the adsorption and hydrolysis efficiency of cellulase. In this study, modified cellobiohydrolases (CBHs) and endoglucanases (EGs) were constructed. Two engineered cellulases CBH-TrCBMV27E,P30D,Link1 and EG-TrCBMV27E,P30D,Link1 well-performed during hydrolysis. Compared to wild-type enzymes, EG-TrCBMV27E,P30D,Link1 had relatively less adsorption ability to lignin and greater affinity to cellulose, especially Avicel. However, for CBH-TrCBMV27E,P30D,Link1, the hydrolysis manner was changed and in favor to hydrolysis process, although the adsorption properties were unexpected. It suggested that various binding conformations of polysaccharide on CBMs hypothetically resulted in different functions of CBMs, including binding ability, processive and digestive properties on fiber surface. Fusion of T. r-CBMV27E,P30D,Link1 to cellulase, both CBH and EG, gave the destruction ability of enzyme and increased the accessible surface of substrate to cellulase, enhanced the adsorption and hydrolysis efficiency of cellulase.
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Affiliation(s)
- Xianqin Lu
- State Key Laboratory of Microbial Technology, Shandong University, No. 72, Binhai Road, Qingdao 266237, PR China
| | - Xiaoting Feng
- State Key Laboratory of Microbial Technology, Shandong University, No. 72, Binhai Road, Qingdao 266237, PR China
| | - Xuezhi Li
- State Key Laboratory of Microbial Technology, Shandong University, No. 72, Binhai Road, Qingdao 266237, PR China
| | - Jian Zhao
- State Key Laboratory of Microbial Technology, Shandong University, No. 72, Binhai Road, Qingdao 266237, PR China.
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10
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Role of ionic strength in the retention and initial attachment ofPseudomonas putidato quartz sand. Biointerphases 2018; 13:041005. [DOI: 10.1116/1.5027735] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Arslan B, Colpan M, Gray KT, Abu-Lail NI, Kostyukova AS. Characterizing interaction forces between actin and proteins of the tropomodulin family reveals the presence of the N-terminal actin-binding site in leiomodin. Arch Biochem Biophys 2017; 638:18-26. [PMID: 29223925 DOI: 10.1016/j.abb.2017.12.005] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 11/18/2017] [Accepted: 12/05/2017] [Indexed: 11/18/2022]
Abstract
Tropomodulin family of proteins includes several isoforms of tropomodulins (Tmod) and leiomodins (Lmod). These proteins can sequester actin monomers or nucleate actin polymerization. Although it is known that their actin-binding properties are isoform-dependent, knowledge on how they vary in strengths of interactions with G-actin is missing. While it is confirmed in many studies that Tmods have two actin-binding sites, information on number and location of actin-binding sites in Lmod2 is controversial. We used atomic force microscopy to study interactions between G-actin and proteins of the tropomodulin family. Unbinding forces between G-actin and Tmod1, Tmod2, Tmod3, or Lmod2 were quantified. Our results indicated that Tmod1 and Tmod3 had unimodal force distributions, Tmod2 had a bimodal distribution and Lmod2 had a trimodal distribution. The number of force distributions correlates with the proteins' abilities to sequester actin or to nucleate actin polymerization. We assigned specific unbinding forces to the individual actin-binding sites of Tmod2 and Lmod2 using mutations that destroy actin-binding sites of Tmod2 and truncated Lmod2. Our results confirm the existence of the N-terminal actin-binding site in Lmod2. Altogether, our data demonstrate how the differences between the number and the strength of actin-binding sites of Tmod or Lmod translate to their functional abilities.
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Affiliation(s)
- Baran Arslan
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164-6515, United States
| | - Mert Colpan
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164-6515, United States; Department of Cellular and Molecular Medicine and Sarver Molecular Cardiovascular Research Program, University of Arizona, Tucson, AZ 85721, United States
| | - Kevin T Gray
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164-6515, United States
| | - Nehal I Abu-Lail
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164-6515, United States.
| | - Alla S Kostyukova
- The Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University, Pullman, WA 99164-6515, United States.
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Lu X, Wang C, Li X, Zhao J. Temperature and pH influence adsorption of cellobiohydrolase onto lignin by changing the protein properties. BIORESOURCE TECHNOLOGY 2017; 245:819-825. [PMID: 28926914 DOI: 10.1016/j.biortech.2017.08.139] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 08/21/2017] [Accepted: 08/22/2017] [Indexed: 05/03/2023]
Abstract
Non-productive adsorption of cellulase onto lignin restricted the movement of cellulase and also hindered the cellulase recycling in bioconversion of lignocellulose. In this study, effect of temperature and pH on adsorption and desorption of cellobiohydrolase (CBH) on lignin and its possible mechanism were discussed. It found that pH value and temperature influenced the adsorption and desorption behaviors of CBH on lignin. Different thermodynamic models suggested that the action between lignin and CBH was physical action. More CBH was adsorbed onto lignin, but lower initial adsorption velocity was detected at 50°C comparing with 4°C. Elevating pH value could improve desorption of cellulase from lignin. The changes of hydrophobicity and electric potential on protein surface may partially explain the impact of environmental conditions on the adsorption and desorption behaviors of CBH on lignin, and comparing to electrical interaction, the hydrophobicity may be the dominating factor influencing the behaviors.
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Affiliation(s)
- Xianqin Lu
- State Key Laboratory of Microbial Technology, Shandong University, Jinan City, Shandong Province 250100, China
| | - Can Wang
- State Key Laboratory of Microbial Technology, Shandong University, Jinan City, Shandong Province 250100, China
| | - Xuezhi Li
- State Key Laboratory of Microbial Technology, Shandong University, Jinan City, Shandong Province 250100, China
| | - Jian Zhao
- State Key Laboratory of Microbial Technology, Shandong University, Jinan City, Shandong Province 250100, China.
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Arslan B, Egerton K, Zhang X, Abu-Lail NI. Effects of the Surface Morphology and Conformations of Lignocellulosic Biomass Biopolymers on Their Nanoscale Interactions with Hydrophobic Self-Assembled Monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2017; 33:6857-6868. [PMID: 28617601 DOI: 10.1021/acs.langmuir.7b01470] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
The effects of the morphology and conformations of the surface biopolymers present on lignocellulosic biomass as well as their steric hindrance on enzymatic adsorption to biomass surfaces remain elusive. In a step to better understand these effects, nanoscale steric forces between a model surface that represents the hydrophobic residues of a cellulase enzyme and a set of reference lignocellulosic substrates were measured using atomic force microscopy (AFM) in liquid media. The reference substrates investigated were prepared by kraft, sulfite, and organosolv pulping pretreatment methods and varied in their surface lignin, xylan, and acetone extractives' contents. Measured steric forces were quantified through fitting to a model developed to describe polyelectrolytes brushes in terms of a brush thickness and a brush grafting density. Our data indicated that cellulose microfibrils extend from the microfibril matrix leading to a long-range steric repulsion and low attractive forces to the hydrophobic model of the enzyme, suggesting that steric hindering can be a possible mechanism for nonproductive binding of enzymes to cellulose. When the amount of xylan increased in the absence of lignin, steric repulsions between the hydrophobic model of the enzyme, and biomass biopolymers decreased as a result of collapsed cellulose microfibrils and adhesion forces increased. This suggests that leaving a small amount of xylan after biomass pretreatment can help improve enzymatic binding to cellulose. Irrespective of the type of lignin present on biomass, grafting densities increased and brush thicknesses decreased compared to those of lignin-free substrates. When compared to lignin-free substrates, lignin-containing substrates had higher attractive forces and lower steric repulsive forces. In addition, AFM images of the reference substrates in the wet and dry states showed that lignin precipitates on the biomass surface where kraft lignin had the highest particle size leading to a limited accessibility of the enzyme to the cellulose in biomass. When the effects of lignin precipitate size, the adhesion force, and steric forces on nonproductive enzymatic binding were all considered, our results indicate that organosolv pretreatment should be the treatment of choice to minimize enzymatic nonproductive binding to 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
| | - Kirstin Egerton
- Gene and Linda Voiland School of Chemical Engineering and Bioengineering, Washington State University , Pullman, Washington 99164-6515, 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
| | - 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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Huang Y, Sun S, Huang C, Yong Q, Elder T, Tu M. Stimulation and inhibition of enzymatic hydrolysis by organosolv lignins as determined by zeta potential and hydrophobicity. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:162. [PMID: 28652863 PMCID: PMC5483266 DOI: 10.1186/s13068-017-0853-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 06/16/2017] [Indexed: 05/24/2023]
Abstract
BACKGROUND Lignin typically inhibits enzymatic hydrolysis of cellulosic biomass, but certain organosolv lignins or lignosulfonates enhance enzymatic hydrolysis. The hydrophobic and electrostatic interactions between lignin and cellulases play critical roles in the enzymatic hydrolysis process. However, how to incorporate these two interactions into the consideration of lignin effects has not been investigated. RESULTS We examined the physicochemical properties and the structures of ethanol organosolv lignins (EOL) from hardwood and softwood and ascertained the association between lignin properties and their inhibitory and stimulatory effects on enzymatic hydrolysis. The zeta potential and hydrophobicity of EOL lignin samples, isolated from organosolv pretreatment of cottonwood (CW), black willow (BW), aspen (AS), eucalyptus (EH), and loblolly pine (LP), were determined and correlated with their effects on enzymatic hydrolysis of Avicel. EOLs from CW, BW, and AS improved the 72 h hydrolysis yield by 8-12%, while EOLs from EH and LP decreased the 72 h hydrolysis yield by 6 and 16%, respectively. The results showed a strong correlation between the 72 h hydrolysis yield with hydrophobicity and zeta potential. The correlation indicated that the hydrophobicity of EOL had a negative effect and the negative zeta potential of EOL had a positive effect. HSQC NMR spectra showed that β-O-4 linkages in lignin react with ethanol to form an α-ethoxylated β-O-4' substructure (A') during organosolv pretreatment. Considerable amounts of C2,6-H2,6 correlation in p-hydroxybenzoate (PB) units were observed for EOL-CW, EOL-BW, and EOL-AS, but not for EOL-EH and EOL-LP. CONCLUSIONS This study revealed that the effect of lignin on enzymatic hydrolysis is a function of both hydrophobic interactions and electrostatic repulsions. The lignin inhibition is controlled by lignin hydrophobicity and the lignin stimulation is governed by the negative zeta potential. The net effect of lignin depends on the combined influence of hydrophobicity and zeta potential. This study has potential implications in biomass pretreatment for the reduction of lignin inhibition by increasing lignin negative zeta potential and decreasing hydrophobicity.
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Affiliation(s)
- Yang Huang
- College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037 China
| | - Shaolong Sun
- Department of Biomedical, Chemical and Environmental Engineering, University of Cincinnati, 2901 Woodside Drive, Cincinnati, OH 45221 USA
| | - Chen Huang
- College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037 China
| | - Qiang Yong
- College of Chemical Engineering, Nanjing Forestry University, Nanjing, 210037 China
| | - Thomas Elder
- USDA-Forest Service, Southern Research Station, 521 Devall Drive, Auburn, AL 36849 USA
| | - Maobing Tu
- Department of Biomedical, Chemical and Environmental Engineering, University of Cincinnati, 2901 Woodside Drive, Cincinnati, OH 45221 USA
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