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Leadbeater DR, Bruce NC. Functional characterisation of a new halotolerant seawater active glycoside hydrolase family 6 cellobiohydrolase from a salt marsh. Sci Rep 2024; 14:3205. [PMID: 38332324 PMCID: PMC10853513 DOI: 10.1038/s41598-024-53886-4] [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: 10/18/2023] [Accepted: 02/06/2024] [Indexed: 02/10/2024] Open
Abstract
Realising a fully circular bioeconomy requires the valorisation of lignocellulosic biomass. Cellulose is the most attractive component of lignocellulose but depolymerisation is inefficient, expensive and resource intensive requiring substantial volumes of potable water. Seawater is an attractive prospective replacement, however seawater tolerant enzymes are required for the development of seawater-based biorefineries. Here, we report a halophilic cellobiohydrolase SMECel6A, identified and isolated from a salt marsh meta-exo-proteome dataset with high sequence divergence to previously characterised cellobiohydrolases. SMECel6A contains a glycoside hydrolase family 6 (GH6) domain and a carbohydrate binding module family 2 (CBM2) domain. Characterisation of recombinant SMECel6A revealed SMECel6A to be active upon crystalline and amorphous cellulose. Mono- and oligosaccharide product profiles revealed cellobiose as the major hydrolysis product confirming SMECel6A as a cellobiohydrolase. We show SMECel6A to be halophilic with optimal activity achieved in 0.5X seawater displaying 80.6 ± 6.93% activity in 1 × seawater. Structural predictions revealed similarity to a characterised halophilic cellobiohydrolase despite sharing only 57% sequence identity. Sequential thermocycling revealed SMECel6A had the ability to partially reversibly denature exclusively in seawater retaining significant activity. Our study confirms that salt marsh ecosystems harbour enzymes with attractive traits with biotechnological potential for implementation in ionic solution based bioprocessing systems.
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Affiliation(s)
- Daniel R Leadbeater
- Centre for Novel Agricultural Products, Department of Biology, University of York, Heslington, York, YO10 5DD, UK.
| | - Neil C Bruce
- Centre for Novel Agricultural Products, Department of Biology, University of York, Heslington, York, YO10 5DD, UK.
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2
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Li P, Wang X, Zhang C, Xu D. Processive binding mechanism of Cel9G from Clostridium cellulovorans: molecular dynamics and free energy landscape investigations. Phys Chem Chem Phys 2023; 25:646-657. [DOI: 10.1039/d2cp04830b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The processive binding mechanism of cellulose by Cel9G from C. cellulovorans was investigated by MD and metadynamics simulations.
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Affiliation(s)
- Penghui Li
- College of Chemistry, MOE Key Laboratory of Green Chemistry and Technology, Sichuan University, Sichuan, Chengdu, 610064, P. R. China
| | - Xin Wang
- College of Chemistry, MOE Key Laboratory of Green Chemistry and Technology, Sichuan University, Sichuan, Chengdu, 610064, P. R. China
| | - Chunchun Zhang
- Analytical & Testing Center, Sichuan University, Sichuan, Chengdu, 610064, P. R. China
| | - Dingguo Xu
- College of Chemistry, MOE Key Laboratory of Green Chemistry and Technology, Sichuan University, Sichuan, Chengdu, 610064, P. R. China
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3
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A processive GH9 family endoglucanase of Bacillus licheniformis and the role of its carbohydrate-binding domain. Appl Microbiol Biotechnol 2022; 106:6059-6075. [PMID: 35948851 DOI: 10.1007/s00253-022-12117-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Revised: 07/23/2022] [Accepted: 07/27/2022] [Indexed: 11/02/2022]
Abstract
One of the critical steps in lignocellulosic deconstruction is the hydrolysis of crystalline cellulose by cellulases. Endoglucanases initially facilitate the breakdown of cellulose in lignocellulosic biomass and are further aided by other cellulases to produce fermentable sugars. Furthermore, if the endoglucanase is processive, it can adsorb to the smooth surface of crystalline cellulose and release soluble sugars during repeated cycles of catalysis before dissociating. Most glycoside hydrolase family 9 (GH9) endoglucanases have catalytic domains linked to a CBM (carbohydrate-binding module) (mostly CBM3) and present the second-largest cellulase family after GH5. GH9 endoglucanases are relatively less characterized. Bacillus licheniformis is a mesophilic soil bacterium containing many glycoside hydrolase (GH) enzymes. We identified an endoglucanase gene, gh9A, encoding the GH9 family enzyme H1AD14 in B. licheniformis and cloned and overexpressed H1AD14 in Escherichia coli. The purified H1AD14 exhibited very high enzymatic activity on endoglucanase substrates, such as β-glucan, lichenan, Avicel, CMC-Na (sodium carboxymethyl cellulose) and PASC (phosphoric acid swollen cellulose), across a wide pH range. The enzyme is tolerant to 2 M sodium chloride and retains 74% specific activity on CMC after 10 days, the highest amongst the reported GH9 endoglucanases. The full-length H1AD14 is a processive endoglucanase and efficiently saccharified sugarcane bagasse. The deletion of the CBM reduces the catalytic activity and processivity. The results add to the sparse knowledge of GH9 endoglucanases and offer the possibility of characterizing and engineering additional enzymes from B. licheniformis toward developing a cellulase cocktail for improved biomass deconstruction. KEY POINTS: • H1AD14 is a highly active and processive GH9 endoglucanase from B. licheniformis. • H1AD14 is thermostable and has a very long half-life. • H1AD14 showed higher saccharification efficiency than commercial endoglucanase.
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4
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Kendrick EG, Bhatia R, Barbosa FC, Goldbeck R, Gallagher JA, Leak DJ. Enzymatic generation of short chain cello-oligosaccharides from Miscanthus using different pretreatments. BIORESOURCE TECHNOLOGY 2022; 358:127399. [PMID: 35640812 DOI: 10.1016/j.biortech.2022.127399] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 05/26/2022] [Accepted: 05/27/2022] [Indexed: 06/15/2023]
Abstract
Enzyme combinations producing short-chain cello-oligosaccharides (COS) as major bio-products from cellulose of Miscanthus Mx2779 accessed through different pretreatment methods were compared. Over short hydrolysis times, processive endoglucanase TfCel9a produced a high percentage of cellotetraose and cellopentaose and is synergistic with endoglucanase CcCel9m for producing short oligomers from amorphous cellulose but had low activity on untreated Miscanthus. Hydrolysis of the latter improved when these were combined with a mutant cellobio/triohydrolase OsCelC7(-105) and a lytic polysaccharide monooxygenase TrCel61a, a combination which also produced the highest COS yields from phosphoric acid swollen cellulose. Steam explosion pretreatment of Miscanthus increased COS yields, with/without phosphoric acid swelling, while increased swelling time (from 20 to 45 min) also increased yields but decreased the need for TrCel61a. The highest COS yields (933 mg/g glucan) and most stable product profile were obtained using ionic liquid [C2mim][OAc] pretreatment and the three enzyme mixture TfCel9a, Cel9m and OsCel7a(-105).
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Affiliation(s)
| | - Rakesh Bhatia
- Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, Plas Gogerddan, Aberystwyth SY23 3EE, UK; Department of Agronomy and Plant Breeding, Justus Liebig University Giessen, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany
| | - Fernando C Barbosa
- Bioprocess and Metabolic Engineering Laboratory, School of Food Engineering, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Rosana Goldbeck
- Bioprocess and Metabolic Engineering Laboratory, School of Food Engineering, University of Campinas (UNICAMP), Campinas, SP, Brazil
| | - Joe A Gallagher
- Institute of Biological, Environmental and Rural Sciences (IBERS), Aberystwyth University, Plas Gogerddan, Aberystwyth SY23 3EE, UK
| | - David J Leak
- Department of Biology & Biochemistry, University of Bath, Bath BA2 7AY, UK.
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5
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Wu M, Lv K, Li J, Wu B, He B. Coevolutionary analysis reveals a distal amino acid residue pair affecting the catalytic activity of GH5 processive endoglucanase from Bacillus subtilis BS-5. Biotechnol Bioeng 2022; 119:2105-2114. [PMID: 35438195 DOI: 10.1002/bit.28113] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 04/05/2022] [Accepted: 04/08/2022] [Indexed: 11/06/2022]
Abstract
EG5C-1, processive endoglucanase from Bacillus subtilis, is a typical bifunctional cellulase with endoglucanase and exoglucanase activities. The engineering of processive endoglucanase focuses on the catalytic pocket or carbohydrate-binding module tailoring based on sequence/structure information. Herein, a computational strategy was applied to identify the desired mutants in the enzyme molecule by evolutionary coupling analysis; subsequently, four residue pairs were selected as evolutionary mutational hotspots. Based on iterative-saturation mutagenesis and subsequent enzymatic activity analysis, a superior mutant K51T/L93T was identified away from the active center. This variant had increased specific activity from 4170 U/µmol of wild-type (WT) to 5678 U/µmol towards CMC-Na and an increase towards the substrate Avicel from 320 U/µmol in WT to 521 U/µmol. In addition, kinetic measurements suggested that superior mutant K51T/L93T had a high substrate affinity (Km ) and a remarkable improvement in catalytic efficiency (kcat /Km ). Furthermore, molecular dynamics simulations revealed that the K51T/L93T mutation altered the spatial conformation at the active site cleft, enhancing the interaction frequency between active site residues and substrate, improving catalytic efficiency and substrate affinity. The current studies provided some perspectives on the effects of distal residue substitution, which might assist in the engineering of processive endoglucanase or other glycoside hydrolases. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Mujunqi Wu
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, 30 Puzhunan road, Nanjing, 211816, Jiangsu, China
| | - Kemin Lv
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, 30 Puzhunan road, Nanjing, 211816, Jiangsu, China
| | - Jiahuang Li
- School of Biopharmacy, China Pharmaceutical University, Nanjing, 211198, Jiangsu, China
| | - Bin Wu
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, 30 Puzhunan road, Nanjing, 211816, Jiangsu, China
| | - Bingfang He
- School of Pharmaceutical Sciences, Nanjing Tech University, 30 Puzhunan road, Nanjing, 211816, Jiangsu, China
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6
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Møller MS, El Bouaballati S, Henrissat B, Svensson B. Functional diversity of three tandem C-terminal carbohydrate-binding modules of a β-mannanase. J Biol Chem 2021; 296:100638. [PMID: 33838183 PMCID: PMC8121702 DOI: 10.1016/j.jbc.2021.100638] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 03/29/2021] [Accepted: 04/05/2021] [Indexed: 11/16/2022] Open
Abstract
Carbohydrate active enzymes, such as those involved in plant cell wall and storage polysaccharide biosynthesis and deconstruction, often contain repeating noncatalytic carbohydrate-binding modules (CBMs) to compensate for low-affinity binding typical of protein–carbohydrate interactions. The bacterium Saccharophagus degradans produces an endo-β-mannanase of glycoside hydrolase family 5 subfamily 8 with three phylogenetically distinct family 10 CBMs located C-terminally from the catalytic domain (SdGH5_8-CBM10x3). However, the functional roles and cooperativity of these CBM domains in polysaccharide binding are not clear. To learn more, we studied the full-length enzyme, three stepwise CBM family 10 (CBM10) truncations, and GFP fusions of the individual CBM10s and all three domains together by pull-down assays, affinity gel electrophoresis, and activity assays. Only the C-terminal CBM10-3 was found to bind strongly to microcrystalline cellulose (dissociation constant, Kd = 1.48 μM). CBM10-3 and CBM10-2 bound galactomannan with similar affinity (Kd = 0.2–0.4 mg/ml), but CBM10-1 had 20-fold lower affinity for this substrate. CBM10 truncations barely affected specific activity on carob galactomannan and konjac glucomannan. Full-length SdGH5_8-CBM10x3 was twofold more active on the highly galactose-decorated viscous guar gum galactomannan and crystalline ivory nut mannan at high enzyme concentrations, but the specific activity was fourfold to ninefold reduced at low enzyme and substrate concentrations compared with the enzyme lacking CBM10-2 and CBM10-3. Comparison of activity and binding data for the different enzyme forms indicates unproductive and productive polysaccharide binding to occur. We conclude that the C-terminal-most CBM10-3 secures firm binding, with contribution from CBM10-2, which with CBM10-1 also provides spatial flexibility.
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Affiliation(s)
- Marie Sofie Møller
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark.
| | - Souad El Bouaballati
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
| | - Bernard Henrissat
- Architecture et Fonction des Macromolécules Biologiques, CNRS, Aix-Marseille Université, Marseille, France; Department of Biological Sciences, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Birte Svensson
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Lyngby, Denmark
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7
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Chen J, Zhang A, Xiang Z, Lu M, Huang P, Gong T, Pan Y, Lin Y, Zhou X, Li Y. EpsR Negatively Regulates Streptococcus mutans Exopolysaccharide Synthesis. J Dent Res 2021; 100:968-976. [PMID: 33749354 DOI: 10.1177/00220345211000668] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Streptococcus mutans is considered the primary etiological agent of human dental caries. Glucosyltransferases (Gtfs) from S. mutans play important roles in the formation of biofilm matrix and the development of cariogenic oral biofilm. Therefore, Gtfs are considered an important target to prevent the development of dental caries. However, the role of transcription factors in regulating gtf expression is not yet clear. Here, we identify a MarR (multiple antibiotic resistance regulator) family transcription factor named EpsR (exopolysaccharide synthesis regulator), which negatively regulates gtfB expression and exopolysaccharide (EPS) production in S. mutans. The epsR in-frame deletion strain grew slowly, aggregated more easily in the presence of dextran, and displayed different colony morphology and biofilm structure. Notably, epsR deletion resulted in altered 3-dimensional biofilm architecture, increased water-insoluble EPS production, and upregulated GtfB protein content and activity. In addition, global gene expression profiling revealed differences in the expression levels of 69 genes in which gtfB was markedly upregulated. The conserved DNA motif for EpsR binding was determined by electrophoretic mobility shift assay and DNase I footprinting assays. Moreover, analysis of β-galactosidase activity suggested that EpsR acted as a repressor and inhibited gtfB expression. Taken together, our findings indicate that EpsR is an important transcription factor that regulates gtfB expression and EPS production in S. mutans. These results add new aspects to the complexity of regulating the expression of genes involved in the cariogenicity of S. mutans, which might lead to novel strategies to prevent the formation of cariogenic biofilm that may favor diseases.
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Affiliation(s)
- J Chen
- Department of Operative Dentistry and Endodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - A Zhang
- Department of Operative Dentistry and Endodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Z Xiang
- Department of Operative Dentistry and Endodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - M Lu
- Department of Operative Dentistry and Endodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - P Huang
- Department of Operative Dentistry and Endodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - T Gong
- Department of Operative Dentistry and Endodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Y Pan
- Department of Operative Dentistry and Endodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Y Lin
- Department of Operative Dentistry and Endodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - X Zhou
- Department of Operative Dentistry and Endodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Y Li
- Department of Operative Dentistry and Endodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
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8
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Raza A, Bashir S, Pothula R, Abdelgaffar H, Tabassum R, Anwar MI, Awais MM, Akhtar M, Jurat-Fuentes JL. Expression and functional characterization in yeast of an endoglucanase from Bacillus sonorensis BD92 and its impact as feed additive in commercial broilers. Int J Biol Macromol 2021; 176:364-375. [PMID: 33549664 DOI: 10.1016/j.ijbiomac.2021.02.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 02/02/2021] [Accepted: 02/02/2021] [Indexed: 11/26/2022]
Abstract
Some ingredients used in poultry feed formulation contain carbohydrate polymers which are difficult to digest and thus hinder nutritional feed value. Toward overcoming this limitation, exogenous enzymes have been added to poultry feed to improve its nutritive value. The present study was designed to provide first enzymatic characterization of endoglucanase (BsEgl) from the genome of B. sonorensis BD92 expressed in Pichia pastoris. Further, we tested its impact alone and in combination with a β-glucosidase (Bteqβgluc) on growth in commercial broilers as feed additive. The expressed enzyme displayed features of GH5 family and had optimum activity against carboxymethyl cellulose at pH 5 and 50 °C. The BsEgl was stable at a range of pH from 4 to 8 for 60 min and at 50 °C for 180 min. Supplementing broilers diet with BsEgl alone or in combination with Bteqβgluc resulted in better feed conversion ratio among treatments during a five weeks testing period. Moreover, meat percentage was also highest for this treatment, and all treatments with recombinant enzymes increased intestinal length in birds compared to treatment control group. Blood parameters and serum biochemistry profile showed non-significant difference among groups. These results support that recombinant cellulolytic enzymes supplement high fiber diets improve their nutritional performance.
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Affiliation(s)
- Ahmad Raza
- National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan; Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad, Pakistan
| | - Saira Bashir
- National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan; Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad, Pakistan.
| | - Ratnasri Pothula
- Department of Entomology and Plant Pathology, University of Tennessee, Knoxville, TN, USA
| | - Heba Abdelgaffar
- Department of Entomology and Plant Pathology, University of Tennessee, Knoxville, TN, USA
| | - Romana Tabassum
- National Institute for Biotechnology and Genetic Engineering (NIBGE), Faisalabad, Pakistan; Pakistan Institute of Engineering and Applied Sciences (PIEAS), Islamabad, Pakistan
| | - Muhammad Irfan Anwar
- Department of Pathobiology, Faculty of Veterinary Sciences, Bahauddin Zakariya University, Multan, Pakistan
| | - Mian Muhammad Awais
- Department of Pathobiology, Faculty of Veterinary Sciences, Bahauddin Zakariya University, Multan, Pakistan
| | - Masood Akhtar
- Department of Pathobiology, Faculty of Veterinary Sciences, Bahauddin Zakariya University, Multan, Pakistan
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9
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A Need for Improved Cellulase Identification from Metagenomic Sequence Data. Appl Environ Microbiol 2020; 87:AEM.01928-20. [PMID: 33067195 DOI: 10.1128/aem.01928-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Improved sequencing technologies and the maturation of metagenomic approaches allow the identification of gene variants with potential industrial applications, including cellulases. Cellulase identification from metagenomic environmental surveys is complicated by inconsistent nomenclature and multiple categorization systems. Here, we summarize the current classification and nomenclature systems, with recommendations for improvements to these systems. Addressing the issues described will strengthen the annotation of cellulose-active enzymes from environmental sequence data sets-a rapidly growing resource in environmental and applied microbiology.
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10
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Lv K, Shao W, Pedroso MM, Peng J, Wu B, Li J, He B, Schenk G. Enhancing the catalytic activity of a GH5 processive endoglucanase from Bacillus subtilis BS-5 by site-directed mutagenesis. Int J Biol Macromol 2020; 168:442-452. [PMID: 33310097 DOI: 10.1016/j.ijbiomac.2020.12.060] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 12/02/2020] [Accepted: 12/07/2020] [Indexed: 11/16/2022]
Abstract
Processive endoglucanases possess both endo- and exoglucanase activity, making them attractive discovery and engineering targets. Here, a processive endoglucanase EG5C-1 from Bacillus subtilis was employed as the starting point for enzyme engineering. Referring to the complex structure information of EG5C-1 and cellohexaose, the amino acid residues in the active site architecture were identified and subjected to alanine scanning mutagenesis. The residues were chosen for a saturation mutagenesis since their variants showed similar activities to EG5C-1. Variants D70Q and S235W showed increased activity towards the substrates CMC and Avicel, an increase was further enhanced in D70Q/S235W double mutant, which displayed a 2.1- and 1.7-fold improvement in the hydrolytic activity towards CMC and Avicel, respectively. In addition, kinetic measurements showed that double mutant had higher substrate affinity (Km) and a significantly higher catalytic efficiency (kcat/Km). The binding isotherms of wild-type EG5C-1 and double mutant D70Q/S235W suggested that the binding capability of EG5C-1 for the insoluble substrate was weaker than that of D70Q/S235W. Molecular dynamics simulations suggested that the collaborative substitutions of D70Q and S235W altered the hydrogen bonding network within the active site architecture and introduced new hydrogen bonds between the enzyme and cellohexaose, thus enhancing both substrate affinity and catalytic efficiency.
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Affiliation(s)
- Kemin Lv
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, 30 Puzhunan road, Nanjing 211816, Jiangsu, China
| | - Wenyu Shao
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, 30 Puzhunan road, Nanjing 211816, Jiangsu, China
| | - Marcelo Monteiro Pedroso
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia
| | - Jiayu Peng
- School of Pharmaceutical Sciences, Nanjing Tech University, 30 Puzhunan road, Nanjing 211816, Jiangsu, China
| | - Bin Wu
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, 30 Puzhunan road, Nanjing 211816, Jiangsu, China.
| | - Jiahuang Li
- School of Life Science, Nanjing University, Nanjing 210023, Jiangsu, China.
| | - Bingfang He
- School of Pharmaceutical Sciences, Nanjing Tech University, 30 Puzhunan road, Nanjing 211816, Jiangsu, China
| | - Gerhard Schenk
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Brisbane, QLD 4072, Australia
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11
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Glycoside hydrolase family 18 chitinases: The known and the unknown. Biotechnol Adv 2020; 43:107553. [DOI: 10.1016/j.biotechadv.2020.107553] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 03/09/2020] [Accepted: 04/20/2020] [Indexed: 12/13/2022]
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12
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Haske-Cornelius O, Hartmann A, Brunner F, Pellis A, Bauer W, Nyanhongo GS, Guebitz GM. Effects of enzymes on the refining of different pulps. J Biotechnol 2020; 320:1-10. [PMID: 32553829 DOI: 10.1016/j.jbiotec.2020.06.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 05/29/2020] [Accepted: 06/09/2020] [Indexed: 11/30/2022]
Abstract
Comparative studies of the effects of two commercial enzyme formulations on fiber refining were conducted. Extensive basic characterisation of the enzymes involved, assessment of their hydrolytic activities on different model substrates as well as on different pulps (softwood sulfate, softwood sulfite, hardwood sulfate) were evaluated. Both enzyme formulations showed endoglucanase as well as some xylanase and β-glucosidase activity. In addition, Enzyme A reached a CMC end viscosity of 19.5 mPa compared to 11.1 mPa for Enzyme B. Reducing sugar release almost doubled from 695 μmol mL-1 for hardwood sulfate pulp to 1300 μmol mL-1 for softwood sulfite pulp with Enzyme B under the same conditions. Enzyme A increased the degree of refining even under non-ideal conditions from 23 °SR to up to 50 °SR. Further characterization of hand sheets, made from enzyme pre-treated and refined cellulose fibers with Enzyme A and B, showed that Enzyme A had the best effects leading to hand sheets with increased tensile strength and low air permeability. In summary, the increase in the degree of refining seen for Enzyme A correlated to higher xylanase and β-glucosidase activity and lower endoglucanase activity.
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Affiliation(s)
- Oskar Haske-Cornelius
- Institute of Environmental Biotechnology, University of Natural Resources and Life Sciences Vienna, Konrad-Lorenz-Strasse 20, 3430, Tulln an der Donau, Austria
| | - Alexandra Hartmann
- Graz University of Technology, Institute of Paper, Pulp and Fiber Technology, Inffeldgasse 23, Graz, 8010, Austria
| | - Florian Brunner
- Institute of Environmental Biotechnology, University of Natural Resources and Life Sciences Vienna, Konrad-Lorenz-Strasse 20, 3430, Tulln an der Donau, Austria
| | - Alessandro Pellis
- Institute of Environmental Biotechnology, University of Natural Resources and Life Sciences Vienna, Konrad-Lorenz-Strasse 20, 3430, Tulln an der Donau, Austria
| | - Wolfgang Bauer
- Graz University of Technology, Institute of Paper, Pulp and Fiber Technology, Inffeldgasse 23, Graz, 8010, Austria
| | - Gibson S Nyanhongo
- Institute of Environmental Biotechnology, University of Natural Resources and Life Sciences Vienna, Konrad-Lorenz-Strasse 20, 3430, Tulln an der Donau, Austria.
| | - Georg M Guebitz
- Institute of Environmental Biotechnology, University of Natural Resources and Life Sciences Vienna, Konrad-Lorenz-Strasse 20, 3430, Tulln an der Donau, Austria; Austrian Centre of Industrial Biotechnology, Konrad-Lorenz-Strasse 20, 3430, Tulln an der Donau, Austria
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Massarente VS, de Araujo Zanoni J, Gomes E, Bonilla-Rodriguez GO. Biochemical characterization of endoglucanases produced by Myceliophthora thermophila M.7.7 in solid-state culture. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2020. [DOI: 10.1016/j.bcab.2020.101684] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Keller MB, Sørensen TH, Krogh KBRM, Wogulis M, Borch K, Westh P. Activity of fungal β-glucosidases on cellulose. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:121. [PMID: 32670408 PMCID: PMC7350674 DOI: 10.1186/s13068-020-01762-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 07/04/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Fungal beta-glucosidases (BGs) from glucoside hydrolase family 3 (GH3) are industrially important enzymes, which convert cellooligosaccharides into glucose; the end product of the cellulolytic process. They are highly active against the β-1,4 glycosidic bond in soluble substrates but typically reported to be inactive against insoluble cellulose. RESULTS We studied the activity of four fungal GH3 BGs on cellulose and found significant activity. At low temperatures (10 ℃), we derived the approximate kinetic parameters k cat = 0.3 ± 0.1 s-1 and K M = 80 ± 30 g/l for a BG from Aspergillus fumigatus (AfBG) acting on Avicel. Interestingly, this maximal turnover is higher than reported values for typical cellobiohydrolases (CBH) at this temperature and comparable to those of endoglucanases (EG). The specificity constant of AfGB on Avicel was only moderately lowered compared to values for EGs and CBHs. CONCLUSIONS Overall these observations suggest a significant promiscuous side activity of the investigated GH3 BGs on insoluble cellulose. This challenges the traditional definition of a BG and supports suggestions that functional classes of cellulolytic enzymes may represent a continuum of overlapping modes of action.
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Affiliation(s)
- Malene B. Keller
- Department of Geosciences and Natural Resource Management, University of Copenhagen, 23 Rolighedsvej, 1958 Frederiksberg, Denmark
- Department of Science and Environment, Roskilde University, 1 Universitetsvej, 4000 Roskilde, Denmark
| | - Trine H. Sørensen
- Department of Science and Environment, Roskilde University, 1 Universitetsvej, 4000 Roskilde, Denmark
- Novozymes A/S, 2 Biologiens Vej, 2800 Kgs. Lyngby, Denmark
| | | | - Mark Wogulis
- Novozymes Ltd, 1445 Drew Ave, Davis, CA 95618 USA
| | - Kim Borch
- Novozymes A/S, 2 Biologiens Vej, 2800 Kgs. Lyngby, Denmark
| | - Peter Westh
- Department of Biotechnology and Biomedicine, Technical University of Denmark, 221 Søltofts Plads, 2800 Kgs. Lyngby, Denmark
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15
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Sørlie M, Horn SJ, Vaaje-Kolstad G, Eijsink VG. Using chitosan to understand chitinases and the role of processivity in the degradation of recalcitrant polysaccharides. REACT FUNCT POLYM 2020. [DOI: 10.1016/j.reactfunctpolym.2020.104488] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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16
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Wang W, Archbold T, Lam JS, Kimber MS, Fan MZ. A processive endoglucanase with multi-substrate specificity is characterized from porcine gut microbiota. Sci Rep 2019; 9:13630. [PMID: 31541154 PMCID: PMC6754456 DOI: 10.1038/s41598-019-50050-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 09/05/2019] [Indexed: 02/08/2023] Open
Abstract
Cellulases play important roles in the dietary fibre digestion in pigs, and have multiple industrial applications. The porcine intestinal microbiota display a unique feature in rapid cellulose digestion. Herein, we have expressed a cellulase gene, p4818Cel5_2A, which singly encoded a catalytic domain belonging to glycoside hydrolase family 5 subfamily 2, and was previously identified from a metagenomic expression library constructed from porcine gut microbiome after feeding grower pigs with a cellulose-supplemented diet. The activity of purified p4818Cel5_2A was maximal at pH 6.0 and 50 °C and displayed resistance to trypsin digestion. This enzyme exhibited activities towards a wide variety of plant polysaccharides, including cellulosic substrates of avicel and solka-Floc®, and the hemicelluloses of β-(1 → 4)/(1 → 3)-glucans, xyloglucan, glucomannan and galactomannan. Viscosity, reducing sugar distribution and hydrolysis product analyses further revealed that this enzyme was a processive endo-β-(1 → 4)-glucanase capable of hydrolyzing cellulose into cellobiose and cellotriose as the primary end products. These catalytic features of p4818Cel5_2A were further explored in the context of a three-dimensional homology model. Altogether, results of this study report a microbial processive endoglucanase identified from the porcine gut microbiome, and it may be tailored as an efficient biocatalyst candidate for potential industrial applications.
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Affiliation(s)
- Weijun Wang
- Department of Animal Biosciences, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
| | - Tania Archbold
- Department of Animal Biosciences, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
| | - Joseph S Lam
- Department of Cellular and Molecular Biology, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
| | - Matthew S Kimber
- Department of Cellular and Molecular Biology, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
| | - Ming Z Fan
- Department of Animal Biosciences, University of Guelph, Guelph, Ontario, N1G 2W1, Canada.
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17
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Processivity and the Mechanisms of Processive Endoglucanases. Appl Biochem Biotechnol 2019; 190:448-463. [DOI: 10.1007/s12010-019-03096-w] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 07/18/2019] [Indexed: 11/26/2022]
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18
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Karnaouri A, Matsakas L, Krikigianni E, Rova U, Christakopoulos P. Valorization of waste forest biomass toward the production of cello-oligosaccharides with potential prebiotic activity by utilizing customized enzyme cocktails. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:285. [PMID: 31827613 PMCID: PMC6902470 DOI: 10.1186/s13068-019-1628-z] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 12/04/2019] [Indexed: 05/19/2023]
Abstract
BACKGROUND Production of value-added materials from lignocellulosic biomass residues is an emerging sector that has attracted much attention as it offers numerous benefits from an environmental and economical point of view. Non-digestible oligosaccharides represent a group of carbohydrates that are resistant to gastrointestinal digestion, and therefore, they are considered as potential prebiotic candidates. Such oligosaccharides can derive from the biomass cellulose fraction through a controlled enzymatic hydrolysis that eliminates the yield of monomers. RESULTS In the present study, hydrolysis of organosolv-pretreated forest residues (birch and spruce) was tested in the presence of four cellulases (EG5, CBH7, CBH6, EG7) and one accessory enzyme (LPMO). The optimal enzyme combinations were comprised of 20% EG5, 43% CBH7, 22% TtLPMO, 10% PaCbh6a and 5% EG7 in the case of birch and 35% EG5, 45% CBH7, 10% TtLPMO, 10% PaCbh6a and 5% EG7 in the case of spruce, leading to 22.3% and 19.1 wt% cellulose conversion into cellobiose, respectively. Enzymatic hydrolysis was applied on scale-up reactions, and the produced oligosaccharides (consisted of > 90% cellobiose) were recovered and separated from glucose through nanofiltration at optimized temperature (50 °C) and pressure (10 bar) conditions, yielding a final product with cellobiose-to-glucose ratio of 21.1 (birch) and 20.2 (spruce). Cellobiose-rich hydrolysates were tested as fermentative substrates for different lactic acid bacteria. It was shown that they can efficiently stimulate the growth of two Lactobacilli strains. CONCLUSIONS Controlled enzymatic hydrolysis with processive cellulases, combined with product recovery and purification, as well as enzyme recycling can potentially support the sustainable production of food-grade oligosaccharides from forest biomass.
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Affiliation(s)
- Anthi Karnaouri
- Biochemical Process Engineering, Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden
| | - Leonidas Matsakas
- Biochemical Process Engineering, Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden
| | - Eleni Krikigianni
- Biochemical Process Engineering, Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden
| | - Ulrika Rova
- Biochemical Process Engineering, Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden
| | - Paul Christakopoulos
- Biochemical Process Engineering, Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden
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Proteomic Dissection of the Cellulolytic Machineries Used by Soil-Dwelling Bacteroidetes. mSystems 2018; 3:mSystems00240-18. [PMID: 30505945 PMCID: PMC6247017 DOI: 10.1128/msystems.00240-18] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 11/02/2018] [Indexed: 11/20/2022] Open
Abstract
Bacteria of the phylum Bacteroidetes are regarded as highly efficient carbohydrate metabolizers, but most species are limited to (semi)soluble glycans. The soil Bacteroidetes species Cytophaga hutchinsonii and Sporocytophaga myxococcoides have long been known as efficient cellulose metabolizers, but neither species conforms to known cellulolytic mechanisms. Both species require contact with their substrate but do not encode cellulosomal systems of cell surface-attached enzyme complexes or the polysaccharide utilization loci found in many other Bacteroidetes species. Here, we have fractionated the cellular compartments of each species from cultures growing on crystalline cellulose and pectin, respectively, and analyzed them using label-free quantitative proteomics as well as enzymatic activity assays. The combined results enabled us to highlight enzymes likely to be important for cellulose conversion and to infer their cellular localization. The combined proteomes represent a wide array of putative cellulolytic enzymes and indicate specific and yet highly redundant mechanisms for cellulose degradation. Of the putative endoglucanases, especially enzymes of hitherto-unstudied glycoside hydrolase family, 8 were abundant, indicating an overlooked important role during cellulose metabolism. Furthermore, both species generated a large number of abundant hypothetical proteins during cellulose conversion, providing a treasure trove of targets for future enzymology studies. IMPORTANCE Cellulose is the most abundant renewable polymer on earth, but its recalcitrance limits highly efficient conversion methods for energy-related and material applications. Though microbial cellulose conversion has been studied for decades, recent advances showcased that large knowledge gaps still exist. Bacteria of the phylum Bacteroidetes are regarded as highly efficient carbohydrate metabolizers, but most species are limited to (semi)soluble glycans. A few species, including the soil bacteria C. hutchinsonii and S. myxococcoides, are regarded as cellulose specialists, but their cellulolytic mechanisms are not understood, as they do not conform to the current models for enzymatic cellulose turnover. By unraveling the proteome setups of these two bacteria during growth on both crystalline cellulose and pectin, we have taken a significant step forward in understanding their idiosyncratic mode of cellulose conversion. This report provides a plethora of new enzyme targets for improved biomass conversion.
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20
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Tsuji A, Yuasa K, Asada C. Cellulose-binding activity of a 21-kDa endo-ß-1,4-glucanase lacking cellulose-binding domain and its synergy with other cellulases in the digestive fluid of Aplysia kurodai. PLoS One 2018; 13:e0205915. [PMID: 30412581 PMCID: PMC6226162 DOI: 10.1371/journal.pone.0205915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 10/03/2018] [Indexed: 12/05/2022] Open
Abstract
Endo-ß-1,4-glucanase AkEG21 belonging to glycosyl hydrolase family 45 (GHF45) is the most abundant cellulase in the digestive fluid of sea hare (Aplysia kurodai). The specific activity of this 21-kDa enzyme is considerably lower than those of other endo ß-1,4-glucanases in the digestive fluid of A. kurodai, therefore its role in whole cellulose hydrolysis by sea hare is still uncertain. Although AkEG21 has a catalytic domain without a cellulose binding domain, it demonstrated stable binding to cellulose fibers, similar to that of fungal cellobiohydrolase (CBH) 1 and CBH 2, which is strongly inhibited by cellohexaose, suggesting the involvement of the catalytic site in cellulose binding. Cellulose-bound AkEG21 hydrolyzed cellulose to cellobiose, cellotriose and cellotetraose, but could not digest an external substrate, azo-carboxymethyl cellulose. Cellulose hydrolysis was considerably stimulated by the synergistic action of cellulose-bound AkEG21 and AkEG45, another ß-1,4-endoglucanase present in the digestive fluid of sea hare; however no synergy in carboxymethylcellulose hydrolysis was observed. When AkEG21 was removed from the digestive fluid by immunoprecipitation, the cellulose hydrolyzing activity of the fluid was significantly reduced, indicating a critical role of AkEG21 in cellulose hydrolysis by A. kurodai. These findings suggest that AkEG21 is a processive endoglucanase functionally equivalent to the CBH, which provides a CBH-independent mechanism for the mollusk to digest seaweed cellulose to glucose.
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Affiliation(s)
- Akihiko Tsuji
- Department of Biomolecular Function and Technology, Graduate School of Bioscience & Bioindustry, Tokushima University, Minamijosanjima, Tokushima, Japan
- * E-mail:
| | - Keizo Yuasa
- Department of Biomolecular Function and Technology, Graduate School of Bioscience & Bioindustry, Tokushima University, Minamijosanjima, Tokushima, Japan
| | - Chikako Asada
- Department of Bioresource Chemistry and Technology, Graduate School of Bioscience & Bioindustry, Tokushima University, Minamijosanjima, Tokushima, Japan
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Kouzuma S, Fujii K. Biochemical characteristics of cellulose and a green alga degradation by Gilvimarinus japonicas 12-2 T, and its application potential for seaweed saccharification. Biosci Biotechnol Biochem 2018; 82:2198-2204. [PMID: 30198387 DOI: 10.1080/09168451.2018.1516542] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Cellulose is one of the major constituents of seaweeds, but reports of mechanisms in microbial seaweed degradation in marine environment are limited, in contrast to the multitude of reports for lignocellulose degradation in terrestrial environment. We studied the biochemical characteristics for marine cellulolytic bacterium Gilvimarinus japonicas 12-2T in seaweed degradation. The bacterial strain was found to degrade green and red algae, but not brown algae. It was shown that the bacterial strain employs various polysaccharide hydrolases (endocellulase, agarase, carrageenanase, xylanase, and laminarinase) to degrade seaweed polysaccharides. Electrophoretic analysis and peptide sequencing showed that the major protein bands on the electrophoresis gel were homologous to known glucanases and glycoside hydrolases. A seaweed hydrolysate harvested from the bacterial culture was found useful as a substrate for yeasts to produce ethanol. These findings will provide insights into possible seaweed decomposition mechanisms of Gilvimarinus, and its biotechnological potential for ethanol production from inedible seaweeds.
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Affiliation(s)
- Shousei Kouzuma
- a Faculty of Agriculture , Yamaguchi University , Yoshida , Japan
| | - Katsuhiko Fujii
- a Faculty of Agriculture , Yamaguchi University , Yoshida , Japan.,b Graduate School of Science and Technology for Innovation , Yamaguchi University , Yoshida , Japan
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22
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Guerriero G, Sergeant K, Legay S, Hausman JF, Cauchie HM, Ahmad I, Siddiqui KS. Novel Insights from Comparative In Silico Analysis of Green Microalgal Cellulases. Int J Mol Sci 2018; 19:E1782. [PMID: 29914107 PMCID: PMC6032398 DOI: 10.3390/ijms19061782] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 06/08/2018] [Accepted: 06/08/2018] [Indexed: 11/24/2022] Open
Abstract
The assumption that cellulose degradation and assimilation can only be carried out by heterotrophic organisms was shattered in 2012 when it was discovered that the unicellular green alga, Chlamydomonas reinhardtii (Cr), can utilize cellulose for growth under CO₂-limiting conditions. Publications of genomes/transcriptomes of the colonial microalgae, Gonium pectorale (Gp) and Volvox carteri (Vc), between 2010⁻2016 prompted us to look for cellulase genes in these algae and to compare them to cellulases from bacteria, fungi, lower/higher plants, and invertebrate metazoans. Interestingly, algal catalytic domains (CDs), belonging to the family GH9, clustered separately and showed the highest (33⁻42%) and lowest (17⁻36%) sequence identity with respect to cellulases from invertebrate metazoans and bacteria, respectively, whereas the identity with cellulases from plants was only 27⁻33%. Based on comparative multiple alignments and homology models, the domain arrangement and active-site architecture of algal cellulases are described in detail. It was found that all algal cellulases are modular, consisting of putative novel cysteine-rich carbohydrate-binding modules (CBMs) and proline/serine-(PS) rich linkers. Two genes were found to encode a protein with a putative Ig-like domain and a cellulase with an unknown domain, respectively. A feature observed in one cellulase homolog from Gp and shared by a spinach cellulase is the existence of two CDs separated by linkers and with a C-terminal CBM. Dockerin and Fn-3-like domains, typically found in bacterial cellulases, are absent in algal enzymes. The targeted gene expression analysis shows that two Gp cellulases consisting, respectively, of a single and two CDs were upregulated upon filter paper addition to the medium.
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Affiliation(s)
- Gea Guerriero
- Environmental Research and Innovation (ERIN) Department, Luxembourg Institute of Science and Technology (LIST), 5 Avenue des Hauts-Fourneaux, L-4362 Esch/Alzette, Luxembourg.
| | - Kjell Sergeant
- Environmental Research and Innovation (ERIN) Department, Luxembourg Institute of Science and Technology (LIST), 5 Avenue des Hauts-Fourneaux, L-4362 Esch/Alzette, Luxembourg.
| | - Sylvain Legay
- Environmental Research and Innovation (ERIN) Department, Luxembourg Institute of Science and Technology (LIST), 5 Avenue des Hauts-Fourneaux, L-4362 Esch/Alzette, Luxembourg.
| | - Jean-Francois Hausman
- Environmental Research and Innovation (ERIN) Department, Luxembourg Institute of Science and Technology (LIST), 5 Avenue des Hauts-Fourneaux, L-4362 Esch/Alzette, Luxembourg.
| | - Henry-Michel Cauchie
- Environmental Research and Innovation (ERIN) Department, Luxembourg Institute of Science and Technology (LIST), 5 Avenue des Hauts-Fourneaux, L-4362 Esch/Alzette, Luxembourg.
| | - Irshad Ahmad
- Life Sciences Department, King Fahd University of Petroleum and Minerals (KFUPM), Dhahran 31261, Saudi Arabia.
| | - Khawar Sohail Siddiqui
- Life Sciences Department, King Fahd University of Petroleum and Minerals (KFUPM), Dhahran 31261, Saudi Arabia.
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Basit A, Akhtar MW. Truncation of the processive Cel5A ofThermotoga maritimaresults in soluble expression and several fold increase in activity. Biotechnol Bioeng 2018; 115:1675-1684. [DOI: 10.1002/bit.26602] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 02/16/2018] [Accepted: 03/19/2018] [Indexed: 11/10/2022]
Affiliation(s)
- Abdul Basit
- School of Biological Sciences; University of the Punjab; Lahore Pakistan
| | - Muhammad W. Akhtar
- School of Biological Sciences; University of the Punjab; Lahore Pakistan
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24
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Karnaouri A, Topakas E, Matsakas L, Rova U, Christakopoulos P. Fine-Tuned Enzymatic Hydrolysis of Organosolv Pretreated Forest Materials for the Efficient Production of Cellobiose. Front Chem 2018; 6:128. [PMID: 29725590 PMCID: PMC5917092 DOI: 10.3389/fchem.2018.00128] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 04/04/2018] [Indexed: 11/23/2022] Open
Abstract
Non-digestible oligosaccharides (NDOs) are likely prebiotic candidates that have been related to the prevention of intestinal infections and other disorders for both humans and animals. Lignocellulosic biomass is the largest carbon source in the biosphere, therefore cello-oligosacharides (COS), especially cellobiose, are potentially the most widely available choice of NDOs. Production of COS and cellobiose with enzymes offers numerous benefits over acid-catalyzed processes, as it is milder, environmentally friendly and produces fewer by-products. Cellobiohydrolases (CBHs) and a class of endoglucanases (EGs), namely processive EGs, are key enzymes for the production of COS, as they have higher preference toward glycosidic bonds near the end of cellulose chains and are able to release soluble products. In this work, we describe the heterologous expression and characterization of two CBHs from the filamentous fungus Thermothelomyces thermophila, as well as their synergism with proccessive EGs for cellobiose release from organosolv pretreated spruce and birch. The properties, inhibition kinetics and substrate specific activities for each enzyme are described in detail. The results show that a combination of EGs belonging to Glycosyl hydrolase families 5, 6, and 9, with a CBHI and CBHII in appropriate proportions, can enhance the production of COS from forest materials, underpinning the potential of these biocatalysts in the production of NDOs.
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Affiliation(s)
- Anthi Karnaouri
- Biochemical Process Engineering, Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden
| | - Evangelos Topakas
- Biochemical Process Engineering, Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden.,Biotechnology Laboratory, Department of Synthesis and Development of Industrial Processes, School of Chemical Engineering, National Technical University of Athens, Athens, Greece
| | - Leonidas Matsakas
- Biochemical Process Engineering, Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden
| | - Ulrika Rova
- Biochemical Process Engineering, Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden
| | - Paul Christakopoulos
- Biochemical Process Engineering, Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden
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25
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Wu B, Zheng S, Pedroso MM, Guddat LW, Chang S, He B, Schenk G. Processivity and enzymatic mechanism of a multifunctional family 5 endoglucanase from Bacillus subtilis BS-5 with potential applications in the saccharification of cellulosic substrates. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:20. [PMID: 29422948 PMCID: PMC5787917 DOI: 10.1186/s13068-018-1022-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2017] [Accepted: 01/11/2018] [Indexed: 05/28/2023]
Abstract
BACKGROUND Presently, enzymes still constitute a major part of the cost of biofuel production from lignocellulosic biomass. Processive endoglucanases, which possess both endoglucanase and exoglucanase activity, have the potential to reduce the costs of biomass saccharification when used together with commercial cellulases. Therefore, the exploration of new processive endoglucanases has attracted much attention with a view to accelerating the industrialization of biofuels and biochemicals. RESULTS The endoglucanase EG5C and its truncated form EG5C-1 from Bacillus subtilis BS-5 were expressed and characterized. EG5C was a typical endoglucanase, comprised of a family 5 catalytic domain and family 3 carbohydrate-binding domain, and which had high activity toward soluble cellulosic substrates, but low activity toward insoluble cellulosic substrates. Importantly, the truncated form EG5C-1 was a processive endoglucanase that hydrolyzed not only carboxymethyl cellulose (CMC), but also insoluble cellulosic substrates. The hydrolytic activities of EG5C-1 towards CMC, phosphoric acid-swollen cellulose (PASC), p-nitrophenyl-β-d-cellobioside, filter paper and Avicel are 4170, 700, 2550, 405 and 320 U/μmol, respectively. These data demonstrated that EG5C-1 had higher activity ratio of exoglucanase to endoglucanase than other known processive endoglucanases. When PASC was degraded by EG5C-1, the ratio of soluble to insoluble reducing sugars was about 3.7 after 3 h of incubation with cellobiose and cellotriose as the main products. Importantly, EG5C-1 alone was able to hydrolyze filter paper and PASC. At 5% substrate concentration and 10 FPU/g PASC enzyme loading, the saccharification yield was 76.5% after 60 h of incubation. Replacement of a phenylalanine residue (F238) by an alanine at the entrance/exit of the substrate binding cleft significantly reduces the ability of EG5C-1 to degrade filter paper and Avicel, but this mutation has little impact on CMCase activity. The processivity of this mutant was also greatly reduced while its cellulose binding ability was markedly enhanced. CONCLUSIONS The processive endoglucanase EG5C-1 from B. subtilis BS-5 exhibits excellent properties that render it a suitable candidate for use in biofuel and biochemical production from lignocellulosic biomass. In addition, our studies also provide useful information for research on enzyme processivity at the molecular level.
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Affiliation(s)
- Bin Wu
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, 30 Puzhunan road, Nanjing, 211816 Jiangsu China
- China Jiangsu National Synergetic Innovation Center for Advanced Materials, 30 Puzhunan road, Nanjing, 211816 Jiangsu China
| | - Shan Zheng
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Brisbane, QLD 4072 Australia
| | - Marcelo Monteiro Pedroso
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Brisbane, QLD 4072 Australia
| | - Luke W. Guddat
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Brisbane, QLD 4072 Australia
| | - Siyuan Chang
- School of Pharmaceutical Sciences, Nanjing Tech University, 30 Puzhunan road, Nanjing, 211816 Jiangsu China
| | - Bingfang He
- China Jiangsu National Synergetic Innovation Center for Advanced Materials, 30 Puzhunan road, Nanjing, 211816 Jiangsu China
- School of Pharmaceutical Sciences, Nanjing Tech University, 30 Puzhunan road, Nanjing, 211816 Jiangsu China
| | - Gerhard Schenk
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Brisbane, QLD 4072 Australia
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The unusual cellulose utilization system of the aerobic soil bacterium Cytophaga hutchinsonii. Appl Microbiol Biotechnol 2017; 101:7113-7127. [PMID: 28849247 DOI: 10.1007/s00253-017-8467-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 08/05/2017] [Indexed: 10/19/2022]
Abstract
Cellulolytic microorganisms play important roles in global carbon cycling and have evolved diverse strategies to digest cellulose. Some are 'generous,' releasing soluble sugars from cellulose extracellularly to feed both themselves and their neighbors. The gliding soil bacterium Cytophaga hutchinsonii exhibits a more 'selfish' strategy. It digests crystalline cellulose using cell-associated cellulases and releases little soluble sugar outside of the cell. The mechanism of C. hutchinsonii cellulose utilization is still poorly understood. In this review, we discuss novel aspects of the C. hutchinsonii cellulolytic system. Recently developed genetic manipulation tools allowed the identification of proteins involved in C. hutchinsonii cellulose utilization. These include periplasmic and cell-surface endoglucanases and novel cellulose-binding proteins. The recently discovered type IX secretion system is needed for cellulose utilization and appears to deliver some of the cellulolytic enzymes and other proteins to the cell surface. The requirement for periplasmic endoglucanases for cellulose utilization is unusual and suggests that cello-oligomers must be imported across the outer membrane before being further digested. Cellobiohydrolases or other predicted processive cellulases that play important roles in many other cellulolytic bacteria appear to be absent in C. hutchinsonii. Cells of C. hutchinsonii attach to and glide along cellulose fibers, which may allow them to find sites most amenable to attack. A model of C. hutchinsonii cellulose utilization summarizing recent progress is proposed.
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Sawant SS, Tran TK, Salunke BK, Kim BS. Potential of Saccharophagus degradans for production of polyhydroxyalkanoates using cellulose. Process Biochem 2017. [DOI: 10.1016/j.procbio.2017.03.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Karnaouri A, Muraleedharan MN, Dimarogona M, Topakas E, Rova U, Sandgren M, Christakopoulos P. Recombinant expression of thermostable processive MtEG5 endoglucanase and its synergism with MtLPMO from Myceliophthora thermophila during the hydrolysis of lignocellulosic substrates. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:126. [PMID: 28515785 PMCID: PMC5432998 DOI: 10.1186/s13068-017-0813-1] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 05/08/2017] [Indexed: 05/02/2023]
Abstract
BACKGROUND Filamentous fungi are among the most powerful cellulolytic organisms in terrestrial ecosystems. To perform the degradation of lignocellulosic substrates, these microorganisms employ both hydrolytic and oxidative mechanisms that involve the secretion and synergism of a wide variety of enzymes. Interactions between these enzymes occur on the level of saccharification, i.e., the release of neutral and oxidized products, but sometimes also reflected in the substrate liquefaction. Although the synergism regarding the yield of neutral sugars has been extensively studied, further studies should focus on the oxidized sugars, as well as the effect of enzyme combinations on the viscosity properties of the substrates. RESULTS In the present study, the heterologous expression of an endoglucanase (EG) and its combined activity together with a lytic polysaccharide monooxygenase (LPMO), both from the thermophilic fungus Myceliophthora thermophila, are described. The EG gene, belonging to the glycoside hydrolase family 5, was functionally expressed in the methylotrophic yeast Pichia pastoris. The produced MtEG5A (75 kDa) featured remarkable thermal stability and showed high specific activity on microcrystalline cellulose compared to CMC, which is indicative of its processivity properties. The enzyme was capable of releasing high amounts of cellobiose from wheat straw, birch, and spruce biomass. Addition of MtLPMO9 together with MtEG5A showed enhanced enzymatic hydrolysis yields against regenerated amorphous cellulose (PASC) by improving the release not only of the neutral but also of the oxidized sugars. Assessment of activity of MtEG5A on the reduction of viscosity of PASC and pretreated wheat straw using dynamic viscosity measurements revealed that the enzyme is able to perform liquefaction of the model substrate and the natural lignocellulosic material, while when added together with MtLPMO9, no further synergistic effect was observed. CONCLUSIONS The endoglucanase MtEG5A from the thermophilic fungus M. thermophila exhibited excellent properties that render it a suitable candidate for use in biotechnological applications. Its strong synergism with LPMO was reflected in sugars release, but not in substrate viscosity reduction. Based on the level of oxidative sugar formation, this is the first indication of synergy between LPMO and EG reported.
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Affiliation(s)
- Anthi Karnaouri
- Biochemical Process Engineering, Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden
| | - Madhu Nair Muraleedharan
- Biochemical Process Engineering, Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden
| | - Maria Dimarogona
- Biotechnology Laboratory, Department of Synthesis and Development of Industrial Processes, School of Chemical Engineering, National Technical University of Athens, Athens, Greece
| | - Evangelos Topakas
- Biochemical Process Engineering, Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden
- Biotechnology Laboratory, Department of Synthesis and Development of Industrial Processes, School of Chemical Engineering, National Technical University of Athens, Athens, Greece
| | - Ulrika Rova
- Biochemical Process Engineering, Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden
| | - Mats Sandgren
- Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Paul Christakopoulos
- Biochemical Process Engineering, Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden
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Leis B, Held C, Bergkemper F, Dennemarck K, Steinbauer R, Reiter A, Mechelke M, Moerch M, Graubner S, Liebl W, Schwarz WH, Zverlov VV. Comparative characterization of all cellulosomal cellulases from Clostridium thermocellum reveals high diversity in endoglucanase product formation essential for complex activity. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:240. [PMID: 29075324 PMCID: PMC5651568 DOI: 10.1186/s13068-017-0928-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 10/10/2017] [Indexed: 05/06/2023]
Abstract
BACKGROUND Clostridium thermocellum is a paradigm for efficient cellulose degradation and a promising organism for the production of second generation biofuels. It owes its high degradation rate on cellulosic substrates to the presence of supra-molecular cellulase complexes, cellulosomes, which comprise over 70 different single enzymes assembled on protein-backbone molecules of the scaffold protein CipA. RESULTS Although all 24 single-cellulosomal cellulases were described previously, we present the first comparative catalogue of all these enzymes together with a comprehensive analysis under identical experimental conditions, including enzyme activity, binding characteristics, substrate specificity, and product analysis. In the course of our study, we encountered four types of distinct enzymatic hydrolysis modes denoted by substrate specificity and hydrolysis product formation: (i) exo-mode cellobiohydrolases (CBH), (ii) endo-mode cellulases with no specific hydrolysis pattern, endoglucanases (EG), (iii) processive endoglucanases with cellotetraose as intermediate product (pEG4), and (iv) processive endoglucanases with cellobiose as the main product (pEG2). These modes are shown on amorphous cellulose and on model cello-oligosaccharides (with degree of polymerization DP 3 to 6). Artificial mini-cellulosomes carrying combinations of cellulases showed their highest activity when all four endoglucanase-groups were incorporated into a single complex. Such a modeled nonavalent complex (n = 9 enzymes bound to the recombinant scaffolding protein CipA) reached half of the activity of the native cellulosome. Comparative analysis of the protein architecture and structure revealed characteristics that play a role in product formation and enzyme processivity. CONCLUSIONS The identification of a new endoglucanase type expands the list of known cellulase functions present in the cellulosome. Our study shows that the variety of processivities in the enzyme complex is a key enabler of its high cellulolytic efficiency. The observed synergistic effect may pave the way for a better understanding of the enzymatic interactions and the design of more active lignocellulose-degrading cellulase cocktails in the future.
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Affiliation(s)
- Benedikt Leis
- Department of Microbiology, Technische Universität München, Emil-Ramann-Str. 4, 85354 Freising, Germany
| | - Claudia Held
- Department of Microbiology, Technische Universität München, Emil-Ramann-Str. 4, 85354 Freising, Germany
| | - Fabian Bergkemper
- Department of Microbiology, Technische Universität München, Emil-Ramann-Str. 4, 85354 Freising, Germany
| | - Katharina Dennemarck
- Department of Microbiology, Technische Universität München, Emil-Ramann-Str. 4, 85354 Freising, Germany
| | - Robert Steinbauer
- Department of Microbiology, Technische Universität München, Emil-Ramann-Str. 4, 85354 Freising, Germany
| | - Alarich Reiter
- Department of Microbiology, Technische Universität München, Emil-Ramann-Str. 4, 85354 Freising, Germany
| | - Matthias Mechelke
- Department of Microbiology, Technische Universität München, Emil-Ramann-Str. 4, 85354 Freising, Germany
| | - Matthias Moerch
- Department of Microbiology, Technische Universität München, Emil-Ramann-Str. 4, 85354 Freising, Germany
| | - Sigrid Graubner
- Department of Microbiology, Technische Universität München, Emil-Ramann-Str. 4, 85354 Freising, Germany
| | - Wolfgang Liebl
- Department of Microbiology, Technische Universität München, Emil-Ramann-Str. 4, 85354 Freising, Germany
| | - Wolfgang H. Schwarz
- Department of Microbiology, Technische Universität München, Emil-Ramann-Str. 4, 85354 Freising, Germany
| | - Vladimir V. Zverlov
- Department of Microbiology, Technische Universität München, Emil-Ramann-Str. 4, 85354 Freising, Germany
- Institute of Molecular Genetics, Russian Academy of Science, Kurchatov Sq. 2, Moscow, 123182 Russia
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Kari J, Kont R, Borch K, Buskov S, Olsen JP, Cruyz-Bagger N, Väljamäe P, Westh P. Anomeric Selectivity and Product Profile of a Processive Cellulase. Biochemistry 2016; 56:167-178. [PMID: 28026938 DOI: 10.1021/acs.biochem.6b00636] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cellobiohydrolases (CBHs) make up an important group of enzymes for both natural carbon cycling and industrial deconstruction of lignocellulosic biomass. The consecutive hydrolysis of one cellulose strand relies on an intricate pattern of enzyme-substrate interactions in the long, tunnel-shaped binding site of the CBH. In this work, we have investigated the initial complexation mode with cellulose of the most thoroughly studied CBH, Cel7A from Hypocrea jecorina (HjCel7A). We found that HjCel7A predominantly produces glucose when it initiates a processive run on insoluble microcrystalline cellulose, confirming the validity of an even and odd product ratio as an estimate of processivity. Moreover, the glucose released from cellulose was predominantly α-glucose. A link between the initial binding mode of the enzyme and the reducing end configuration was investigated by inhibition studies with the two anomers of cellobiose. A clear preference for β-cellobiose in product binding site +2 was observed for HjCel7A, but not the homologous endoglucanase, HjCe7B. Possible relationships between this anomeric preference in the product site and the prevalence of odd-numbered initial-cut products are discussed, and a correlation between processivity and anomer selectivity is proposed.
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Affiliation(s)
- Jeppe Kari
- Research Unit for Functional Biomaterials, Roskilde University , Roskilde, Denmark
| | - Riin Kont
- Institute of Molecular and Cell Biology, University of Tartu , Tartu, Estonia
| | - Kim Borch
- Novozymes A/S , Krogshøjvej 36, DK-2880 Bagsværd, Denmark
| | - Steen Buskov
- Novozymes A/S , Krogshøjvej 36, DK-2880 Bagsværd, Denmark
| | - Johan Pelck Olsen
- Research Unit for Functional Biomaterials, Roskilde University , Roskilde, Denmark
| | | | - Priit Väljamäe
- Institute of Molecular and Cell Biology, University of Tartu , Tartu, Estonia
| | - Peter Westh
- Research Unit for Functional Biomaterials, Roskilde University , Roskilde, Denmark
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Lee HJ, Kim IJ, Youn HJ, Yun EJ, Choi IG, Kim KH. Cellotriose-hydrolyzing activity conferred by truncating the carbohydrate-binding modules of Cel5 from Hahella chejuensis. Bioprocess Biosyst Eng 2016; 40:241-249. [PMID: 27761654 DOI: 10.1007/s00449-016-1692-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 10/07/2016] [Indexed: 01/30/2023]
Abstract
Processivity is a typical characteristic of cellobiohydrolases (CBHs); it enables the enzyme to successively hydrolyze the ends of cellulose chains and to produce cellobiose as the major product. Some microbes, which do not have CBHs, utilize endoglucanases (EGs) that exhibit processivity, commonly referred to as processive EGs. A processive EG identified from Hahella chejuensis, HcCel5, has a catalytic domain (CD) belonging to the glycoside hydrolase family 5 (GH5) and two carbohydrate-binding modules (CBM6s). In this study, we compared HcCel5-CD with the CD of Saccharophagus degradans Cel5H (SdCel5H-CD), which is a processive EG reported previously. Our results showed that in comparison to SdCel5H-CD, HcCel5-CD has more suitable characteristics for cellulose hydrolysis, such as higher hydrolytic activity, thermostability (40-80 °C), and processivity. Noticeably, HcCel5-CD is capable of hydrolyzing cellotriose, unlike HcCel5. These features of HcCel5-CD for cellulose hydrolysis could be employed for efficient saccharification of lignocellulose to produce cellobiose and glucose, which may be used to produce renewable fuels and chemicals.
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Affiliation(s)
- Hee Jin Lee
- Department of Biotechnology, Graduate School, Korea University, Seoul, 02841, South Korea.,Ildong Pharmaceutical, Hwaseong, 18449, South Korea
| | - In Jung Kim
- Department of Biotechnology, Graduate School, Korea University, Seoul, 02841, South Korea
| | - Hak Jin Youn
- Department of Biotechnology, Graduate School, Korea University, Seoul, 02841, South Korea
| | - Eun Ju Yun
- Department of Biotechnology, Graduate School, Korea University, Seoul, 02841, South Korea
| | - In-Geol Choi
- Department of Biotechnology, Graduate School, Korea University, Seoul, 02841, South Korea
| | - Kyoung Heon Kim
- Department of Biotechnology, Graduate School, Korea University, Seoul, 02841, South Korea.
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Extra carbohydrate binding module contributes to the processivity and catalytic activity of a non-modular hydrolase family 5 endoglucanase from Fomitiporia mediterranea MF3/22. Enzyme Microb Technol 2016; 91:42-51. [DOI: 10.1016/j.enzmictec.2016.06.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 04/12/2016] [Accepted: 06/01/2016] [Indexed: 11/23/2022]
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Periplasmic Cytophaga hutchinsonii Endoglucanases Are Required for Use of Crystalline Cellulose as the Sole Source of Carbon and Energy. Appl Environ Microbiol 2016; 82:4835-4845. [PMID: 27260354 DOI: 10.1128/aem.01298-16] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 05/25/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The soil bacterium Cytophaga hutchinsonii actively digests crystalline cellulose by a poorly understood mechanism. Genome analyses identified nine genes predicted to encode endoglucanases with roles in this process. No predicted cellobiohydrolases, which are usually involved in the utilization of crystalline cellulose, were identified. Chromosomal deletions were performed in eight of the endoglucanase-encoding genes: cel5A, cel5B, cel5C, cel9A, cel9B, cel9C, cel9E, and cel9F Each mutant retained the ability to digest crystalline cellulose, although the deletion of cel9C caused a modest decrease in cellulose utilization. Strains with multiple deletions were constructed to identify the critical cellulases. Cells of a mutant lacking both cel5B and cel9C were completely deficient in growth on cellulose. Cell fractionation and biochemical analyses indicate that Cel5B and Cel9C are periplasmic nonprocessive endoglucanases. The requirement of periplasmic endoglucanases for cellulose utilization suggests that cellodextrins are transported across the outer membrane during this process. Bioinformatic analyses predict that Cel5A, Cel9A, Cel9B, Cel9D, and Cel9E are secreted across the outer membrane by the type IX secretion system, which has been linked to cellulose utilization. These secreted endoglucanases may perform the initial digestion within amorphous regions on the cellulose fibers, releasing oligomers that are transported into the periplasm for further digestion by Cel5B and Cel9C. The results suggest that both cell surface and periplasmic endoglucanases are required for the growth of C. hutchinsonii on cellulose and that novel cell surface proteins may solubilize and transport cellodextrins across the outer membrane. IMPORTANCE The bacterium Cytophaga hutchinsonii digests crystalline cellulose by an unknown mechanism. It lacks processive cellobiohydrolases that are often involved in cellulose digestion. Critical cellulolytic enzymes were identified by genetic analyses. Intracellular (periplasmic) nonprocessive endoglucanases performed an important role in cellulose utilization. The results suggest a model involving partial digestion at the cell surface, solubilization and uptake of cellodextrins across the outer membrane by an unknown mechanism, and further digestion within the periplasm. The ability to sequester cellodextrins and digest them intracellularly may limit losses of soluble cellobiose to other organisms. C. hutchinsonii uses an unusual approach to digest cellulose and is a potential source of novel proteins to increase the efficiency of conversion of cellulose into soluble sugars and biofuels.
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Lafond M, Sulzenbacher G, Freyd T, Henrissat B, Berrin JG, Garron ML. The Quaternary Structure of a Glycoside Hydrolase Dictates Specificity toward β-Glucans. J Biol Chem 2016; 291:7183-94. [PMID: 26755730 DOI: 10.1074/jbc.m115.695999] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2015] [Indexed: 02/05/2023] Open
Abstract
In the Carbohydrate-Active Enzyme (CAZy) database, glycoside hydrolase family 5 (GH5) is a large family with more than 6,000 sequences. Among the 51 described GH5 subfamilies, subfamily GH5_26 contains members that display either endo-β(1,4)-glucanase or β(1,3;1,4)-glucanase activities. In this study, we focused on the GH5_26 enzyme fromSaccharophagus degradans(SdGluc5_26A), a marine bacterium known for its capacity to degrade a wide diversity of complex polysaccharides.SdGluc5_26A displays lichenase activity toward β(1,3;1,4)-glucans with a side cellobiohydrolase activity toward β(1,4)-glucans. The three-dimensional structure ofSdGluc5_26A adopts a stable trimeric quaternary structure also observable in solution. The N-terminal region ofSdGluc5_26A protrudes into the active site of an adjacent monomer. To understand whether this occupation of the active site could influence its activity, we conducted a comprehensive enzymatic characterization ofSdGluc5_26A and of a mutant truncated at the N terminus. Ligand complex structures and kinetic analyses reveal that the N terminus governs the substrate specificity ofSdGluc5_26A. Its deletion opens the enzyme cleft at the -3 subsite and turns the enzyme into an endo-β(1,4)-glucanase. This study demonstrates that experimental approaches can reveal structure-function relationships out of reach of current bioinformatic predictions.
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Affiliation(s)
- Mickael Lafond
- From the Institut des Sciences Moléculaires de Marseille-BiosCiences, UMR7313 CNRS, Aix-Marseille University, Pôle de l'Etoile, 13284 Marseille, France, the INRA, UMR1163, Biodiversité et Biotechnologie Fongiques, Aix-Marseille University, Polytech'Marseille, F-13288 Marseille, France
| | - Gerlind Sulzenbacher
- the Architecture et Fonction des Macromolécules Biologiques, UMR7257 CNRS, Aix-Marseille University, F-13288 Marseille, France, the INRA, USC1408 Architecture et Fonction des Macromolécules Biologiques, F-13288 Marseille, France, and
| | - Thibaud Freyd
- the Architecture et Fonction des Macromolécules Biologiques, UMR7257 CNRS, Aix-Marseille University, F-13288 Marseille, France
| | - Bernard Henrissat
- the Architecture et Fonction des Macromolécules Biologiques, UMR7257 CNRS, Aix-Marseille University, F-13288 Marseille, France, the INRA, USC1408 Architecture et Fonction des Macromolécules Biologiques, F-13288 Marseille, France, and the Department of Biological Sciences, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Jean-Guy Berrin
- the INRA, UMR1163, Biodiversité et Biotechnologie Fongiques, Aix-Marseille University, Polytech'Marseille, F-13288 Marseille, France,
| | - Marie-Line Garron
- the Architecture et Fonction des Macromolécules Biologiques, UMR7257 CNRS, Aix-Marseille University, F-13288 Marseille, France, the INRA, USC1408 Architecture et Fonction des Macromolécules Biologiques, F-13288 Marseille, France, and
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CenC, a multidomain thermostable GH9 processive endoglucanase from Clostridium thermocellum: cloning, characterization and saccharification studies. World J Microbiol Biotechnol 2015; 31:1699-710. [DOI: 10.1007/s11274-015-1920-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 08/03/2015] [Indexed: 01/29/2023]
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36
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Nam YW, Nihira T, Arakawa T, Saito Y, Kitaoka M, Nakai H, Fushinobu S. Crystal Structure and Substrate Recognition of Cellobionic Acid Phosphorylase, Which Plays a Key Role in Oxidative Cellulose Degradation by Microbes. J Biol Chem 2015; 290:18281-92. [PMID: 26041776 DOI: 10.1074/jbc.m115.664664] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Indexed: 01/02/2023] Open
Abstract
The microbial oxidative cellulose degradation system is attracting significant research attention after the recent discovery of lytic polysaccharide mono-oxygenases. A primary product of the oxidative and hydrolytic cellulose degradation system is cellobionic acid (CbA), the aldonic acid form of cellobiose. We previously demonstrated that the intracellular enzyme belonging to glycoside hydrolase family 94 from cellulolytic fungus and bacterium is cellobionic acid phosphorylase (CBAP), which catalyzes reversible phosphorolysis of CbA into glucose 1-phosphate and gluconic acid (GlcA). In this report, we describe the biochemical characterization and the three-dimensional structure of CBAP from the marine cellulolytic bacterium Saccharophagus degradans. Structures of ligand-free and complex forms with CbA, GlcA, and a synthetic disaccharide product from glucuronic acid were determined at resolutions of up to 1.6 Å. The active site is located near the dimer interface. At subsite +1, the carboxylate group of GlcA and CbA is recognized by Arg-609 and Lys-613. Additionally, one residue from the neighboring protomer (Gln-190) is involved in the carboxylate recognition of GlcA. A mutational analysis indicated that these residues are critical for the binding and catalysis of the aldonic and uronic acid acceptors GlcA and glucuronic acid. Structural and sequence comparisons with other glycoside hydrolase family 94 phosphorylases revealed that CBAPs have a unique subsite +1 with a distinct amino acid residue conservation pattern at this site. This study provides molecular insight into the energetically efficient metabolic pathway of oxidized sugars that links the oxidative cellulolytic pathway to the glycolytic and pentose phosphate pathways in cellulolytic microbes.
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Affiliation(s)
- Young-Woo Nam
- From the Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Takanori Nihira
- Faculty of Agriculture, Niigata University, Niigata 950-2181, Japan, and
| | - Takatoshi Arakawa
- From the Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Yuka Saito
- Faculty of Agriculture, Niigata University, Niigata 950-2181, Japan, and
| | - Motomitsu Kitaoka
- National Food Research Institute, National Agriculture and Food Research Organization, Tsukuba, Ibaraki 305-8642, Japan
| | - Hiroyuki Nakai
- Faculty of Agriculture, Niigata University, Niigata 950-2181, Japan, and
| | - Shinya Fushinobu
- From the Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan,
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The directionality of processive enzymes acting on recalcitrant polysaccharides is reflected in the kinetic signatures of oligomer degradation. FEBS Lett 2015; 589:1807-12. [DOI: 10.1016/j.febslet.2015.05.034] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Revised: 04/17/2015] [Accepted: 05/20/2015] [Indexed: 11/18/2022]
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Xu X, Li J, Zhang W, Huang H, Shi P, Luo H, Liu B, Zhang Y, Zhang Z, Fan Y, Yao B. A Neutral Thermostable β-1,4-Glucanase from Humicola insolens Y1 with Potential for Applications in Various Industries. PLoS One 2015; 10:e0124925. [PMID: 25909505 PMCID: PMC4409357 DOI: 10.1371/journal.pone.0124925] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Accepted: 03/10/2015] [Indexed: 01/26/2023] Open
Abstract
We cloned a new glycoside hydrolase family 6 gene, Hicel6C, from the thermophilic fungus Humicola insolens Y1 and expressed it in Pichia pastoris. Using barley β-glucan as a substrate, recombinant HiCel6C protein exhibited neutral pH (6.5) and high temperature (70°C) optima. Distinct from most reported acidic fungal endo-β-1,4-glucanases, HiCel6C was alkali-tolerant, retaining greater than 98.0, 61.2, and 27.6% of peak activity at pH 8.0, 9.0, and 10.0, respectively, and exhibited good stability over a wide pH range (pH 5.0−11.0) and at temperatures up to 60°C. The Km and Vmax values of HiCel6C for barley β-glucan were 1.29 mg/mL and 752 μmol/min·mg, respectively. HiCel6C was strictly specific for the β-1,4-glucoside linkage exhibiting activity toward barley β-glucan, lichenan, and carboxy methylcellulose sodium salt (CMC-Na), but not toward laminarin (1,3-β-glucan). HiCel6C cleaved the internal glycosidic linkages of cellooligosaccharides randomly and thus represents an endo-cleaving enzyme. The predominant product of polysaccharide hydrolysis by HiCel6C was cellobiose, suggesting that it functions by an endo-processive mechanism. The favorable properties of HiCel6C make it a good candidate for basic research and for applications in the textile and brewing industries.
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Affiliation(s)
- Xinxin Xu
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Jinyang Li
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Wei Zhang
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
- * E-mail: (WZ); (BY)
| | - Huoqing Huang
- Key Laboratory of Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Pengjun Shi
- Key Laboratory of Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Huiying Luo
- Key Laboratory of Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Bo Liu
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Yuhong Zhang
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Zhifang Zhang
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Yunliu Fan
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Bin Yao
- Key Laboratory of Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, China
- * E-mail: (WZ); (BY)
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Zhu Y, Kwiatkowski KJ, Yang T, Kharade SS, Bahr CM, Koropatkin NM, Liu W, McBride MJ. Outer membrane proteins related to SusC and SusD are not required for Cytophaga hutchinsonii cellulose utilization. Appl Microbiol Biotechnol 2015; 99:6339-50. [DOI: 10.1007/s00253-015-6555-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 03/13/2015] [Accepted: 03/16/2015] [Indexed: 11/29/2022]
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Payne CM, Knott BC, Mayes HB, Hansson H, Himmel ME, Sandgren M, Ståhlberg J, Beckham GT. Fungal Cellulases. Chem Rev 2015; 115:1308-448. [DOI: 10.1021/cr500351c] [Citation(s) in RCA: 533] [Impact Index Per Article: 59.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Christina M. Payne
- Department
of Chemical and Materials Engineering and Center for Computational
Sciences, University of Kentucky, 177 F. Paul Anderson Tower, Lexington, Kentucky 40506, United States
| | - Brandon C. Knott
- National
Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver
West Parkway, Golden, Colorado 80401, United States
| | - Heather B. Mayes
- Department
of Chemical and Biological Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208, United States
| | - Henrik Hansson
- Department
of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, Uppsala BioCenter, Almas allé 5, SE-75651 Uppsala, Sweden
| | - Michael E. Himmel
- Biosciences
Center, National Renewable Energy Laboratory, 15013 Denver West Parkway, Golden, Colorado 80401, United States
| | - Mats Sandgren
- Department
of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, Uppsala BioCenter, Almas allé 5, SE-75651 Uppsala, Sweden
| | - Jerry Ståhlberg
- Department
of Chemistry and Biotechnology, Swedish University of Agricultural Sciences, Uppsala BioCenter, Almas allé 5, SE-75651 Uppsala, Sweden
| | - Gregg T. Beckham
- National
Bioenergy Center, National Renewable Energy Laboratory, 15013 Denver
West Parkway, Golden, Colorado 80401, United States
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41
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Customized optimization of cellulase mixtures for differently pretreated rice straw. Bioprocess Biosyst Eng 2014; 38:929-37. [DOI: 10.1007/s00449-014-1338-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 12/08/2014] [Indexed: 10/24/2022]
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Gastelum-Arellanez A, Paredes-López O, Olalde-Portugal V. Extracellular endoglucanase activity from Paenibacillus polymyxa BEb-40: production, optimization and enzymatic characterization. World J Microbiol Biotechnol 2014; 30:2953-65. [DOI: 10.1007/s11274-014-1723-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Accepted: 08/14/2014] [Indexed: 10/24/2022]
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Kim IJ, Lee HJ, Choi IG, Kim KH. Synergistic proteins for the enhanced enzymatic hydrolysis of cellulose by cellulase. Appl Microbiol Biotechnol 2014; 98:8469-80. [PMID: 25129610 DOI: 10.1007/s00253-014-6001-3] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2014] [Revised: 07/28/2014] [Accepted: 07/29/2014] [Indexed: 01/09/2023]
Abstract
Reducing the enzyme loadings for enzymatic saccharification of lignocellulose is required for economically feasible production of biofuels and biochemicals. One strategy is addition of small amounts of synergistic proteins to cellulase mixtures. Synergistic proteins increase the activity of cellulase without causing significant hydrolysis of cellulose. Synergistic proteins exert their activity by inducing structural modifications in cellulose. Recently, synergistic proteins from various biological sources, including bacteria, fungi, and plants, were identified based on genomic data, and their synergistic activities were investigated. Currently, an up-to-date overview of several aspects of synergistic proteins, such as their functions, action mechanisms and synergistic activity, are important for future industrial application. In this review, we summarize the current state of research on four synergistic proteins: carbohydrate-binding modules, plant expansins, expansin-like proteins, and Auxiliary Activity family 9 (formerly GH61) proteins. This review provides critical information to aid in promoting research on the development of efficient and industrially feasible synergistic proteins.
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Affiliation(s)
- In Jung Kim
- Department of Biotechnology, Korea University Graduate School, Seoul, 136-713, Republic of Korea
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44
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Towards a molecular-level theory of carbohydrate processivity in glycoside hydrolases. Curr Opin Biotechnol 2014; 27:96-106. [DOI: 10.1016/j.copbio.2013.12.002] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2013] [Accepted: 12/04/2013] [Indexed: 10/25/2022]
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45
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Zhang C, Wang Y, Li Z, Zhou X, Zhang W, Zhao Y, Lu X. Characterization of a multi-function processive endoglucanase CHU_2103 from Cytophaga hutchinsonii. Appl Microbiol Biotechnol 2014; 98:6679-87. [DOI: 10.1007/s00253-014-5640-8] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2014] [Revised: 02/20/2014] [Accepted: 02/23/2014] [Indexed: 11/28/2022]
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46
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47
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Ghatge SS, Telke AA, Kang SH, Arulalapperumal V, Lee KW, Govindwar SP, Um Y, Oh DB, Shin HD, Kim SW. Characterization of modular bifunctional processive endoglucanase Cel5 from Hahella chejuensis KCTC 2396. Appl Microbiol Biotechnol 2013; 98:4421-35. [PMID: 24343767 DOI: 10.1007/s00253-013-5446-0] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2013] [Revised: 11/28/2013] [Accepted: 11/28/2013] [Indexed: 11/29/2022]
Abstract
Cel5 from marine Hahella chejuensis is composed of glycoside hydrolase family-5 (GH5) catalytic domain (CD) and two carbohydrate binding modules (CBM6-2). The enzyme was expressed in Escherichia coli and purified to homogeneity. The optimum endoglucanase and xylanase activities of recombinant Cel5 were observed at 65 °C, pH 6.5 and 55 °C, pH 5.5, respectively. It exhibited K m of 1.8 and 7.1 mg/ml for carboxymethyl cellulose and birchwood xylan, respectively. The addition of Ca(2+) greatly improved thermostability and endoglucanase activity of Cel5. The Cel5 retained 90 % of its endoglucanase activity after 24 h incubation in presence of 5 M concentration of NaCl. Recombinant Cel5 showed production of cellobiose after hydrolysis of cellulosic substrates (soluble/insoluble) and methylglucuronic acid substituted xylooligosaccharides after hydrolysis of glucuronoxylans by endo-wise cleavage. These results indicated that Cel5 as bifunctional enzyme having both processive endoglucanase and xylanase activities. The multidomain structure of Cel5 is clearly distinguished from the GH5 bifunctional glycoside hydrolases characterized to date, which are single domain enzymes. Sequence analysis and homology modeling suggested presence of two conserved binding sites with different substrate specificities in CBM6-2 and a single catalytic site in CD. Residues Glu132 and Glu219 were identified as key catalytic amino acids by sequence alignment and further verified by using site directed mutagenesis. CBM6-2 plays vital role in catalytic activity and thermostability of Cel5. The bifunctional activities and multiple substrate specificities of Cel5 can be utilized for efficient hydrolysis of cellulose and hemicellulose into soluble sugars.
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Affiliation(s)
- Sunil Subhash Ghatge
- Division of Applied Life Sciences (BK21), PMBBRC, Gyeongsang National University, Jinju, Gyeongnam, Republic of Korea
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48
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Deletion of the Cytophaga hutchinsonii type IX secretion system gene sprP results in defects in gliding motility and cellulose utilization. Appl Microbiol Biotechnol 2013; 98:763-75. [PMID: 24257839 DOI: 10.1007/s00253-013-5355-2] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 10/16/2013] [Accepted: 10/21/2013] [Indexed: 10/26/2022]
Abstract
Cytophaga hutchinsonii glides rapidly over surfaces and employs a novel collection of cell-associated proteins to digest crystalline cellulose. HimarEm1 transposon mutagenesis was used to isolate a mutant with an insertion in CHU_0170 (sprP) that was partially deficient in gliding motility and was unable to digest filter paper cellulose. SprP is similar in sequence to the Porphyromonas gingivalis type IX secretion system (T9SS) protein PorP that is involved in the secretion of gingipain protease virulence factors and to the Flavobacterium johnsoniae T9SS protein SprF that is needed to deliver components of the gliding motility machinery to the cell surface. We developed an efficient method to construct targeted nonpolar mutations in C. hutchinsonii and deleted sprP. The deletion mutant was defective in gliding and failed to digest cellulose, and complementation with sprP on a plasmid restored both abilities. Sequence analysis predicted that CHU_3105 is secreted by the T9SS, and deletion of sprP resulted in decreased levels of extracellular CHU_3105. The results suggest that SprP may function in protein secretion. The T9SS may be required for motility and cellulose utilization because cell surface proteins predicted to be involved in both processes have C-terminal domains that are thought to target them to this secretion system. The efficient genetic tools now available for C. hutchinsonii should allow a detailed analysis of the cellulolytic, gliding motility, and protein secretion machineries of this common but poorly understood bacterium.
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Feasibility test of utilizing Saccharophagus degradans 2-40(T) as the source of crude enzyme for the saccharification of lignocellulose. Bioprocess Biosyst Eng 2013; 37:707-10. [PMID: 23990129 DOI: 10.1007/s00449-013-1040-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Accepted: 08/17/2013] [Indexed: 10/26/2022]
Abstract
In the conversion of lignocellulose into high-value products, including fuels and chemicals, the production of cellulase and the enzymatic hydrolysis for producing fermentable sugar are the largest contributors to the cost of production of the final products. The marine bacterium Saccharophagus degradans 2-40(T) can degrade more than ten different complex polysaccharides found in the ocean, including cellulose and xylan. Accordingly, S. degradans has been actively considered as a practical source of crude enzymes needed for the saccharification of lignocellulose to produce ethanol by others including a leading commercial company. However, the overall enzyme system of S. degradans for hydrolyzing cellulose and hemicellulose has not been quantitatively evaluated yet in comparison with commercial enzymes. In this study, the inductions and activities of cellulase and xylanase of cell-free lysate of S. degradans were investigated. The growth of S. degradans cells and the activities of cellulase and xylanase were promoted by adding 2 % of cellulose and xylan mixture (cellulose:xylan = 4:3 in mass ratio) to the aquarium salt medium supplemented with 0.2 % glucose. The specific cellulase activity of the cell-free lysate of S. degradans, as determined by the filter paper activity assay, was approximately 70 times lower than those of commercial cellulases, including Celluclast 1.5 L and Accellerase 1000. These results imply that significant improvement in the cellulase activity of S. degradans is needed for the industrial uses of S. degradans as the enzyme source.
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50
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Sakatoku A, Tanaka D, Kamachi H, Nakamura S. Cloning and Characterizing the Thermophilic and Detergent Stable Cellulase CelMytB from Saccharophagus sp. Myt-1. Indian J Microbiol 2013; 54:20-6. [PMID: 24426162 DOI: 10.1007/s12088-013-0421-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2013] [Accepted: 07/08/2013] [Indexed: 10/26/2022] Open
Abstract
We previously isolated and reported a second species of the Saccharophagus genus, Saccharophagus sp. strain Myt-1. In the present study, a cellulase gene (celMytB) from the genomic DNA of Myt-1 was cloned and characterized. The DNA sequence fragment contained an open reading frame of 1,893 bp that encoded a protein of 631 amino acids with an estimated molecular mass of 66.8 kDa. The deduced protein, CelMytB, had a catalytic domain that contained a conserved signature sequence (VIYEIYNEPL) of glycosyl hydrolase family 5 and a CBM6 cellulose binding module. CelMytB showed optimal activity at 55 °C and pH 6.5, which is similar to the optimal temperature and pH profile of cel5H, an endoglucanase from the closely related S. degradans 2-40. However, the cellulase (degradation of soluble cellulose) and avicelase (degradation of crystalline cellulose) activities of CelMytB were about 3-fold and 100-fold higher, respectively, than the equivalent activities of cel5H. Moreover, CelMytB could degrade xylan. From the zymogram results, we speculated that the catalytic domain of CelMytB had high activity even without the cellulose binding module. The presence of some detergents stimulated the cellulase activity of CelMytB.
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Affiliation(s)
- Akihiro Sakatoku
- Department of Environmental and Energy Science, Faculty of Earth and Environmental Systems, Graduate School of Science and Engineering, University of Toyama, Toyama, 930-8555 Japan
| | - Daisuke Tanaka
- Department of Environmental and Energy Science, Faculty of Earth and Environmental Systems, Graduate School of Science and Engineering, University of Toyama, Toyama, 930-8555 Japan
| | - Hiroyuki Kamachi
- Department of Environmental and Energy Science, Faculty of Earth and Environmental Systems, Graduate School of Science and Engineering, University of Toyama, Toyama, 930-8555 Japan
| | - Shogo Nakamura
- Department of Environmental and Energy Science, Faculty of Earth and Environmental Systems, Graduate School of Science and Engineering, University of Toyama, Toyama, 930-8555 Japan
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