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Mafa MS, Malgas S. Towards an understanding of the enzymatic degradation of complex plant mannan structures. World J Microbiol Biotechnol 2023; 39:302. [PMID: 37688610 PMCID: PMC10492685 DOI: 10.1007/s11274-023-03753-7] [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: 07/06/2023] [Accepted: 09/04/2023] [Indexed: 09/11/2023]
Abstract
Plant cell walls are composed of a heterogeneous mixture of polysaccharides that require several different enzymes to degrade. These enzymes are important for a variety of biotechnological processes, from biofuel production to food processing. Several classical mannanolytic enzyme functions of glycoside hydrolases (GH), such as β-mannanase, β-mannosidase and α-galactosidase activities, are helpful for efficient mannan hydrolysis. In this light, we bring three enzymes into the model of mannan degradation that have received little or no attention. By linking their three-dimensional structures and substrate specificities, we have predicted the interactions and cooperativity of these novel enzymes with classical mannanolytic enzymes for efficient mannan hydrolysis. The novel exo-β-1,4-mannobiohydrolases are indispensable for the production of mannobiose from the terminal ends of mannans, this product being the preferred product for short-chain mannooligosaccharides (MOS)-specific β-mannosidases. Second, the side-chain cleaving enzymes, acetyl mannan esterases (AcME), remove acetyl decorations on mannan that would have hindered backbone cleaving enzymes, while the backbone cleaving enzymes liberate MOS, which are preferred substrates of the debranching and sidechain cleaving enzymes. The nonhydrolytic expansins and swollenins disrupt the crystalline regions of the biomass, improving their accessibility for AcME and GH activities. Finally, lytic polysaccharide monooxygenases have also been implicated in promoting the degradation of lignocellulosic biomass or mannan degradation by classical mannanolytic enzymes, possibly by disrupting adsorbed mannan residues. Modelling effective enzymatic mannan degradation has implications for improving the saccharification of biomass for the synthesis of value-added and upcycling of lignocellulosic wastes.
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Affiliation(s)
- Mpho Stephen Mafa
- Carbohydrates and Enzymology Laboratory (CHEM-LAB), Department of Plant Sciences, University of the Free State, Bloemfontein, 9300 South Africa
| | - Samkelo Malgas
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Hatfield, 0028 South Africa
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Malgas S, Thoresen M, Moses V, Prinsloo E, Susan van Dyk J, Pletschke BI. Analysis of the galactomannan binding ability of β-mannosidases, BtMan2A and CmMan5A, regarding their activity and synergism with a β-mannanase. Comput Struct Biotechnol J 2022; 20:3140-3150. [PMID: 35782739 PMCID: PMC9232400 DOI: 10.1016/j.csbj.2022.06.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 06/14/2022] [Accepted: 06/14/2022] [Indexed: 11/28/2022] Open
Abstract
BtMan2A preferred short manno-oligomers, while CmMan5A preferred longer ones; DP >2. BtMan2A displayed stronger irreversible binding to galactomannan than CmMan5A. BtMan2A binding to galactomannan did not affect its activity, while CmMan5A lost activity. BtMan2A binding was pH-dependent, with increased binding ability at lower pH. CmMan5A synergised with CcManA, while BtMan2A did not – even though the enzyme was active. High loadings of BtMan2A abolished CcManA activity; at protein ratios ≥ 5:1.
Both β-mannanases and β-mannosidases are required for mannan-backbone degradation into mannose. In this study, two β-mannosidases of glycoside hydrolase (GH) families 2 (BtMan2A) and 5 (CmMan5A) were evaluated for their substrate specificities and galactomannan binding ability. BtMan2A preferred short manno-oligomers, while CmMan5A preferred longer ones; DP >2, and galactomannans. BtMan2A displayed irreversible galactomannan binding, which was pH-dependent, with higher binding observed at low pH, while CmMan5A had limited binding. Docking and molecular dynamics (MD) simulations showed that BtMan2A galactomannan binding was stronger under acidic conditions (-8.4 kcal/mol) than in a neutral environment (-7.6 kcal/mol), and the galactomannan ligand was more unstable under neutral conditions than acidic conditions. Qualitative surface plasmon resonance (SPR) experimentally confirmed the reduced binding capacity of BtMan2A at pH 7. Finally, synergistic β-mannanase to β-mannosidase (BtMan2A or CmMan5A) ratios required for maximal galactomannan hydrolysis were determined. All CcManA to CmMan5A combinations were synergistic (≈1.2-fold), while combinations of CcManA with BtMan2A (≈1.0-fold) yielded no hydrolysis improvement. In conclusion, the low specific activity of BtMan2A towards long and galactose-containing oligomers and its non-catalytic galactomannan binding ability led to no synergy with the mannanase, making GH2 mannosidases ineffective for use in cocktails for mannan degradation.
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Affiliation(s)
- Samkelo Malgas
- Enzyme Science Programme (ESP), Department of Biochemistry and Microbiology, Rhodes University, Makhanda, Eastern Cape 6140, South Africa
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Hatfield, Gauteng 0028, South Africa
- Corresponding author at: Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Hatfield, Gauteng 0028, South Africa.
| | - Mariska Thoresen
- Enzyme Science Programme (ESP), Department of Biochemistry and Microbiology, Rhodes University, Makhanda, Eastern Cape 6140, South Africa
| | - Vuyani Moses
- Research Unit in Bioinformatics (RUBi), Department of Biochemistry and Microbiology, Rhodes University, Makhanda, Eastern Cape 6140, South Africa
| | - Earl Prinsloo
- Biotechnology Innovation Centre, Rhodes University, Makhanda, Eastern Cape 6140, South Africa
| | - J. Susan van Dyk
- Forest Products Biotechnology, University of British Columbia, 2424 Main Mall, Vancouver, British Columbia V6T1Z4, Canada
| | - Brett I. Pletschke
- Enzyme Science Programme (ESP), Department of Biochemistry and Microbiology, Rhodes University, Makhanda, Eastern Cape 6140, South Africa
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Combination of CTec2 and GH5 or GH26 Endo-Mannanases for Effective Lignocellulosic Biomass Degradation. Catalysts 2020. [DOI: 10.3390/catal10101193] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Among endo-mannanases, glycoside hydrolase (GH) family 26 enzymes have been shown to be more catalytically active than GH5 enzymes on mannans. However, only GH5 endo-mannanases have been used for the formulation of enzyme cocktails. In this study, Bacillus sp.-derived GH5 and GH26 endo-mannanases were comparatively analysed biochemically for their synergistic action with a commercial cellulase blend, CTec2, during pre-treated lignocellulose degradation. Substrate specificity and thermo-stability studies on mannan substrates showed that GH26 endo-mannanase was more catalytically active and stable than GH5. GH26 also exhibited higher binding affinity for mannan than GH5, while GH5 showed more affinity for lignocellulosic substrates than GH26. Applying the endo-mannanases in combination with CTec2 for lignocellulose degradation led to synergism with a 1.3-fold increase in reducing sugar release compared to when CTec2 was used alone. This study showed that using the activity of endo-mannanases displayed with model substrates is a poor predictor of their activity and synergism on complex lignocelluloses.
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The Second-Generation Biomethane from Mandarin Orange Peel under Cocultivation with Methanogens and the Armed Clostridium cellulovorans. FERMENTATION-BASEL 2019. [DOI: 10.3390/fermentation5040095] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
This study demonstrates that the consortium, which consists of the microbial flora of methane production (MFMP) and Clostridium cellulovorans grown with cellulose, can perform the direct conversion of cellulosic biomass to methane. The MFMP was taken from a commercial methane fermentation tank and was extremely complicated. Therefore, C. cellulovorans grown with cellobiose could not perform high degradation ability on cellulosic biomass due to competition by various microorganisms in MFMP. Focusing on the fact that C. cellulovorans was cultivated with cellulose, which is armed with cellulosome, so that it is now armed C. cellulovorans; the direct conversion was carried out by the consortium which consisted of MFMP and the armed C. cellulovorans. As a result, the consortium of C. cellulovorans grown with cellobiose and MFMP (CCeM) could not degrade the purified cellulose and mandarin orange peel. However, MFMP and the armed C. cellulovorans reduced 78.4% of the total sugar of the purified cellulose such as MN301, and produced 6.89 mL of methane simultaneously. Furthermore, the consortium consisted of MFMP and the armed C. cellulovorans degraded mandarin orange peel without any pretreatments and produced methane that was accounting for 66.2% of the total produced gas.
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Tomita H, Okazaki F, Tamaru Y. Biomethane production from sugar beet pulp under cocultivation with Clostridium cellulovorans and methanogens. AMB Express 2019; 9:28. [PMID: 30778890 PMCID: PMC6379495 DOI: 10.1186/s13568-019-0752-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Accepted: 02/08/2019] [Indexed: 12/11/2022] Open
Abstract
This study was demonstrated with a coculture fermentation system using sugar beet pulp (SBP) as a carbon source combining the cellulose-degrading bacterium Clostridium cellulovorans with microbial flora of methane production (MFMP) for the direct conversion of cellulosic biomass to methane (CH4). The MFMP was taken from a commercial methane fermentation plant and extremely complicated. Therefore, the MFMP was analyzed by a next-generation sequencing system and the microbiome was identified and classified based on several computer programs. As a result, Methanosarcina mazei (1.34% of total counts) and the other methanogens were found in the MFMP. Interestingly, the simultaneous utilization of hydrogen (H2) and carbon dioxide (CO2) for methanogenesis was observed in the coculture with Consortium of C. cellulovorans with the MFMP (CCeM) including M. mazei. Furthermore, the CCeM degraded 87.3% of SBP without any pretreatment and produced 34.0 L of CH4 per 1 kg of dry weight of SBP. Thus, a gas metabolic shift in the fermentation pattern of C. cellulovorans was observed in the CCeM coculture. These results indicated that degradation of agricultural wastes was able to be carried out simultaneously with CH4 production by C. cellulovorans and the MFMP.
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Kucharska K, Rybarczyk P, Hołowacz I, Łukajtis R, Glinka M, Kamiński M. Pretreatment of Lignocellulosic Materials as Substrates for Fermentation Processes. Molecules 2018; 23:E2937. [PMID: 30423814 PMCID: PMC6278514 DOI: 10.3390/molecules23112937] [Citation(s) in RCA: 146] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Revised: 11/01/2018] [Accepted: 11/08/2018] [Indexed: 11/17/2022] Open
Abstract
Lignocellulosic biomass is an abundant and renewable resource that potentially contains large amounts of energy. It is an interesting alternative for fossil fuels, allowing the production of biofuels and other organic compounds. In this paper, a review devoted to the processing of lignocellulosic materials as substrates for fermentation processes is presented. The review focuses on physical, chemical, physicochemical, enzymatic, and microbiologic methods of biomass pretreatment. In addition to the evaluation of the mentioned methods, the aim of the paper is to understand the possibilities of the biomass pretreatment and their influence on the efficiency of biofuels and organic compounds production. The effects of different pretreatment methods on the lignocellulosic biomass structure are described along with a discussion of the benefits and drawbacks of each method, including the potential generation of inhibitory compounds for enzymatic hydrolysis, the effect on cellulose digestibility, the generation of compounds that are toxic for the environment, and energy and economic demand. The results of the investigations imply that only the stepwise pretreatment procedure may ensure effective fermentation of the lignocellulosic biomass. Pretreatment step is still a challenge for obtaining cost-effective and competitive technology for large-scale conversion of lignocellulosic biomass into fermentable sugars with low inhibitory concentration.
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Affiliation(s)
- Karolina Kucharska
- Department of Process Engineering and Chemical Technology, Faculty of Chemistry, Gdańsk University of Technology, 80-233 Gdańsk, Poland.
| | - Piotr Rybarczyk
- Department of Process Engineering and Chemical Technology, Faculty of Chemistry, Gdańsk University of Technology, 80-233 Gdańsk, Poland.
| | - Iwona Hołowacz
- Department of Process Engineering and Chemical Technology, Faculty of Chemistry, Gdańsk University of Technology, 80-233 Gdańsk, Poland.
| | - Rafał Łukajtis
- Department of Process Engineering and Chemical Technology, Faculty of Chemistry, Gdańsk University of Technology, 80-233 Gdańsk, Poland.
| | - Marta Glinka
- Department of Process Engineering and Chemical Technology, Faculty of Chemistry, Gdańsk University of Technology, 80-233 Gdańsk, Poland.
- Department of Analytical Chemistry, Faculty of Chemistry, Gdańsk University of Technology, 80-233 Gdańsk, Poland.
| | - Marian Kamiński
- Department of Process Engineering and Chemical Technology, Faculty of Chemistry, Gdańsk University of Technology, 80-233 Gdańsk, Poland.
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Alves LDF, Meleiro LP, Silva RN, Westmann CA, Guazzaroni ME. Novel Ethanol- and 5-Hydroxymethyl Furfural-Stimulated β-Glucosidase Retrieved From a Brazilian Secondary Atlantic Forest Soil Metagenome. Front Microbiol 2018; 9:2556. [PMID: 30420843 PMCID: PMC6215845 DOI: 10.3389/fmicb.2018.02556] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Accepted: 10/08/2018] [Indexed: 11/13/2022] Open
Abstract
Beta-glucosidases are key enzymes involved in lignocellulosic biomass degradation for bioethanol production, which complete the final step during cellulose hydrolysis by converting cellobiose into glucose. Currently, industry requires enzymes with improved catalytic performance or tolerance to process-specific parameters. In this sense, metagenomics has become a powerful tool for accessing and exploring the biochemical biodiversity present in different natural environments. Here, we report the identification of a novel β-glucosidase from metagenomic DNA isolated from soil samples enriched with decaying plant matter from a Secondary Atlantic Forest region. For this, we employed a functional screening approach using an optimized and synthetic broad host-range vector for library production. The novel β-glucosidase – named Lfa2 – displays three GH3-family conserved domains and conserved catalytic amino acids D283 and E487. The purified enzyme was most active in pH 5.5 and at 50°C, and showed hydrolytic activity toward several pNP synthetic substrates containing β-glucose, β-galactose, β-xylose, β-fucose, and α-arabinopyranose, as well as toward cellobiose. Lfa2 showed considerable glucose tolerance, exhibiting an IC50 of 300 mM glucose and 30% of remaining activity in 600 mM glucose. In addition, Lfa2 retained full or slightly enhanced activity in the presence of several metal ions. Further, β-glucosidase activity was increased by 1.7-fold in the presence of 10% (v/v) ethanol, a concentration that can be reached in conventional fermentation processes. Similarly, Lfa2 showed 1.7-fold enhanced activity at high concentrations of 5-hydroxymethyl furfural, one of the most important cellulase inhibitors in pretreated sugarcane bagasse hydrolysates. Moreover, the synergistic effect of Lfa2 on Bacillus subtilis GH5-CBM3 endoglucanase activity was demonstrated by the increased production of glucose (1.6-fold). Together, these results indicate that β-glucosidase Lfa2 is a promissory enzyme candidate for utilization in diverse industrial applications, such as cellulosic biomass degradation or flavor enhancement in winemaking and grape processing.
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Affiliation(s)
- Luana de Fátima Alves
- Department of Biochemistry and Immunology, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Luana Parras Meleiro
- Department of Chemistry, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Roberto N Silva
- Department of Biochemistry and Immunology, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - Cauã Antunes Westmann
- Department of Cellular and Molecular Biology, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
| | - María-Eugenia Guazzaroni
- Department of Biology, Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto, Universidade de São Paulo, São Paulo, Brazil
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Nakajima D, Shibata T, Tanaka R, Kuroda K, Ueda M, Miyake H. Characterization of the cellulosomal scaffolding protein CbpC from Clostridium cellulovorans 743B. J Biosci Bioeng 2017; 124:376-380. [PMID: 28533157 DOI: 10.1016/j.jbiosc.2017.04.014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 04/18/2017] [Accepted: 04/20/2017] [Indexed: 12/15/2022]
Abstract
Clostridium cellulovorans 743B, an anaerobic and mesophilic bacterium, produces an extracellular enzyme complex called the cellulosome on the cell surface. Recently, we have reported the whole genome sequence of C. cellulovorans, which revealed that a total of 4 cellulosomal scaffolding proteins: CbpA, HbpA, CbpB, and CbpC were encoded in the C. cellulovorans genome. In particular, cbpC encoded a 429-residue polypeptide that includes a carbohydrate-binding module (CBM), an S-layer homology module, and a cohesin. CbpC was also detected in the culture supernatant of C. cellulovorans. Genomic DNA coding for CbpC was subcloned into a pET-22b+ vector in order to express and produce the recombinant protein in Escherichia coli BL21(DE3). Measurement of CbpC adsorption to crystalline cellulose indicated a dissociation constant of 0.60 μM, which is a similar to that of CBM from CbpA. We also subcloned the region encoding xylanase B (XynB) with the dockerin from C. cellulovorans and analyzed the interaction between XynB and CbpC by GST pull-down assay. It was observed that GST-CbpC assembles with XynB to form a minimal cellulosome. The activity of XynB against rice straw tended to be increased in the presence of CbpC. These results showed a synergistic effect on rice straw as a representative cellulosic biomass through the formation of a minimal cellulosome containing XynB bound to CbpC. Thus, our findings provide a foundation for the development of cellulosic biomass saccharification using a minimal cellulosome.
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Affiliation(s)
- Daichi Nakajima
- Graduate School of Bioresources, Mie University, 1577 Kurimamachiya-cho, Tsu, Mie 514-8507, Japan
| | - Toshiyuki Shibata
- Graduate School of Bioresources, Mie University, 1577 Kurimamachiya-cho, Tsu, Mie 514-8507, Japan
| | - Reiji Tanaka
- Graduate School of Bioresources, Mie University, 1577 Kurimamachiya-cho, Tsu, Mie 514-8507, Japan
| | - Kouichi Kuroda
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Mitsuyoshi Ueda
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan
| | - Hideo Miyake
- Graduate School of Bioresources, Mie University, 1577 Kurimamachiya-cho, Tsu, Mie 514-8507, Japan; Life Science Research Center, Mie University, 1577 Kurimamachiya-cho, Tsu, Mie 514-8507, Japan.
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Gama R, Van Dyk JS, Burton MH, Pletschke BI. Using an artificial neural network to predict the optimal conditions for enzymatic hydrolysis of apple pomace. 3 Biotech 2017; 7:138. [PMID: 28593522 DOI: 10.1007/s13205-017-0754-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 01/23/2017] [Indexed: 10/19/2022] Open
Abstract
The enzymatic degradation of lignocellulosic biomass such as apple pomace is a complex process influenced by a number of hydrolysis conditions. Predicting optimal conditions, including enzyme and substrate concentration, temperature and pH can improve conversion efficiency. In this study, the production of sugar monomers from apple pomace using commercial enzyme preparations, Celluclast 1.5L, Viscozyme L and Novozyme 188 was investigated. A limited number of experiments were carried out and then analysed using an artificial neural network (ANN) to model the enzymatic hydrolysis process. The ANN was used to simulate the enzymatic hydrolysis process for a range of input variables and the optimal conditions were successfully selected as was indicated by the R 2 value of 0.99 and a small MSE value. The inputs for the ANN were substrate loading, enzyme loading, temperature, initial pH and a combination of these parameters, while release profiles of glucose and reducing sugars were the outputs. Enzyme loadings of 0.5 and 0.2 mg/g substrate and a substrate loading of 30% were optimal for glucose and reducing sugar release from apple pomace, respectively, resulting in concentrations of 6.5 g/L glucose and 28.9 g/L reducing sugars. Apple pomace hydrolysis can be successfully carried out based on the predicted optimal conditions from the ANN.
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Katsimpouras C, Dimarogona M, Petropoulos P, Christakopoulos P, Topakas E. A thermostable GH26 endo-β-mannanase from Myceliophthora thermophila capable of enhancing lignocellulose degradation. Appl Microbiol Biotechnol 2016; 100:8385-97. [PMID: 27193267 DOI: 10.1007/s00253-016-7609-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Revised: 04/24/2016] [Accepted: 05/01/2016] [Indexed: 10/21/2022]
Abstract
The endomannanase gene em26a from the thermophilic fungus Myceliophthora thermophila, belonging to the glycoside hydrolase family 26, was functionally expressed in the methylotrophic yeast Pichia pastoris. The putative endomannanase, dubbed MtMan26A, was purified to homogeneity (60 kDa) and subsequently characterized. The optimum pH and temperature for the enzymatic activity of MtMan26A were 6.0 and 60 °C, respectively. MtMan26A showed high specific activity against konjac glucomannan and carob galactomannan, while it also exhibited high thermal stability with a half-life of 14.4 h at 60 °C. Thermostability is of great importance, especially in industrial processes where harsh conditions are employed. With the aim of better understanding its structure-function relationships, a homology model of MtMan26A was constructed, based on the crystallographic structure of a close homologue. Finally, the addition of MtMan26A as a supplement to the commercial enzyme mixture Celluclast® 1.5 L and Novozyme® 188 resulted in enhanced enzymatic hydrolysis of pretreated beechwood sawdust, improving the release of total reducing sugars and glucose by 13 and 12 %, respectively.
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Affiliation(s)
- Constantinos Katsimpouras
- Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, 9 Iroon Polytechniou Str., Zografou Campus, Athens, 15780, Greece
| | - Maria Dimarogona
- Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, 9 Iroon Polytechniou Str., Zografou Campus, Athens, 15780, Greece
| | - Pericles Petropoulos
- Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, 9 Iroon Polytechniou Str., Zografou Campus, Athens, 15780, Greece
| | - Paul Christakopoulos
- Biochemical and Chemical Process Engineering, Division of Sustainable Process Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, SE-97187, Luleå, Sweden
| | - Evangelos Topakas
- Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, 9 Iroon Polytechniou Str., Zografou Campus, Athens, 15780, Greece.
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11
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The inhibitory effects of various substrate pre-treatment by-products and wash liquors on mannanolytic enzymes. ACTA ACUST UNITED AC 2016. [DOI: 10.1016/j.molcatb.2015.11.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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12
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Identification of glycosyl hydrolases from a metagenomic library of microflora in sugarcane bagasse collection site and their cooperative action on cellulose degradation. J Biosci Bioeng 2015; 119:384-91. [DOI: 10.1016/j.jbiosc.2014.09.010] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2014] [Revised: 08/12/2014] [Accepted: 09/13/2014] [Indexed: 11/19/2022]
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13
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Malgas S, van Dyk SJ, Pletschke BI. β-Mannanase (Man26A) and α-galactosidase (Aga27A) synergism – A key factor for the hydrolysis of galactomannan substrates. Enzyme Microb Technol 2015; 70:1-8. [DOI: 10.1016/j.enzmictec.2014.12.007] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Revised: 12/08/2014] [Accepted: 12/14/2014] [Indexed: 11/29/2022]
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14
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Khelil O, Choubane S, Cheba BA. Co-production of Cellulases and Manganese Peroxidases by Bacillus sp. R2 and Bacillus Cereus 11778 on Waste Newspaper: Application in Dyes Decolourization. ACTA ACUST UNITED AC 2015. [DOI: 10.1016/j.protcy.2015.02.140] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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15
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Lozano Goné AM, Dinorín Téllez Girón J, Jiménez Montejo FE, Hidalgo-Lara ME, López y López VE. Behavior of Transition State Regulator AbrB in Batch Cultures of Bacillus thuringiensis. Curr Microbiol 2014; 69:725-32. [DOI: 10.1007/s00284-014-0650-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 05/20/2014] [Indexed: 10/25/2022]
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16
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Kumar R, Wyman CE. Strong cellulase inhibition by Mannan polysaccharides in cellulose conversion to sugars. Biotechnol Bioeng 2014; 111:1341-53. [PMID: 24522973 DOI: 10.1002/bit.25218] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2013] [Revised: 01/24/2014] [Accepted: 02/06/2014] [Indexed: 11/08/2022]
Abstract
Cellulase enzymes contribute a major fraction of the total cost for biological conversion of lignocellulosic biomass to fuels and chemicals. Although a several fold reduction in cellulase production costs and enhancement of cellulase activity and stability have been reported in recent years, sugar yields are still lower at low enzyme doses than desired commercially. We recently reported that hemicellulose xylan and its oligomers strongly inhibit cellulase and that supplementation of cellulase with xylanase and β-xylosidase would significantly reduce such inhibition. In this study, mannan polysaccharides and their enzymatically prepared hydrolyzates were discovered to be strongly inhibitory to fungal cellulase in cellulose conversion (>50% drop in % relative conversion), even at a small concentration of 0.1 g/L, and inhibition was much greater than experienced by other known inhibitors such as cellobiose, xylooligomers, and furfural. Furthermore, cellulase inhibition dramatically increased with heteromannan loading and mannan substitution with galactose side units. In general, enzymatically prepared hydrolyzates were less inhibitory than their respective mannan polysaccharides except highly substituted ones. Supplementation of cellulase with commercial accessory enzymes such as xylanase, pectinase, and β-glucosidase was effective in greatly relieving inhibition but only for less substituted heteromannans. However, cellulase supplementation with purified heteromannan specific enzymes relieved inhibition by these more substituted heteromannans as well, suggesting that commercial preparations need to have higher amounts of such activities to realize high sugar yields at the low enzyme protein loadings needed for low cost fuels production.
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Affiliation(s)
- Rajeev Kumar
- Center for Environmental Research and Technology (CE-CERT), Bourns College of Engineering, University of California, Riverside, 1084 Columbia Avenue, Riverside, California, 92507; BioEnergy Science Center (BESC), Oak Ridge National Laboratory, Oak Ridge, Tennessee, 37831-6422.
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Uçkun Kiran E, Akpinar O, Bakir U. Improvement of enzymatic xylooligosaccharides production by the co-utilization of xylans from different origins. FOOD AND BIOPRODUCTS PROCESSING 2013. [DOI: 10.1016/j.fbp.2012.12.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Van Dyk JS, Pletschke BI. A review of lignocellulose bioconversion using enzymatic hydrolysis and synergistic cooperation between enzymes--factors affecting enzymes, conversion and synergy. Biotechnol Adv 2012; 30:1458-80. [PMID: 22445788 DOI: 10.1016/j.biotechadv.2012.03.002] [Citation(s) in RCA: 476] [Impact Index Per Article: 39.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Revised: 02/10/2012] [Accepted: 03/06/2012] [Indexed: 02/04/2023]
Abstract
Lignocellulose is a complex substrate which requires a variety of enzymes, acting in synergy, for its complete hydrolysis. These synergistic interactions between different enzymes have been investigated in order to design optimal combinations and ratios of enzymes for different lignocellulosic substrates that have been subjected to different pretreatments. This review examines the enzymes required to degrade various components of lignocellulose and the impact of pretreatments on the lignocellulose components and the enzymes required for degradation. Many factors affect the enzymes and the optimisation of the hydrolysis process, such as enzyme ratios, substrate loadings, enzyme loadings, inhibitors, adsorption and surfactants. Consideration is also given to the calculation of degrees of synergy and yield. A model is further proposed for the optimisation of enzyme combinations based on a selection of individual or commercial enzyme mixtures. The main area for further study is the effect of and interaction between different hemicellulases on complex substrates.
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Affiliation(s)
- J S Van Dyk
- Department of Biochemistry, Microbiology and Biotechnology, Rhodes University, PO Box 94, Grahamstown, 6140, South Africa
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Pavón-Orozco P, Santiago-Hernández A, Rosengren A, Hidalgo-Lara ME, Stålbrand H. The family II carbohydrate-binding module of xylanase CflXyn11A from Cellulomonas flavigena increases the synergy with cellulase TrCel7B from Trichoderma reesei during the hydrolysis of sugar cane bagasse. BIORESOURCE TECHNOLOGY 2012; 104:622-30. [PMID: 22169213 DOI: 10.1016/j.biortech.2011.11.068] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Revised: 10/20/2011] [Accepted: 11/18/2011] [Indexed: 05/25/2023]
Abstract
Synergy between Cellulomonas flavigena xylanase CflXyn11A and Trichoderma reesei endoglucanase TrCel7B was assessed during hydrolysis of alkaline pretreated sugar cane bagasse (SCB) after 12-48 h, applying the individual enzymes and mixtures of the enzymes. A high degree of synergy (6.3) between CflXyn11A and TrCel7B in hydrolysis of SCB was observed after 12h in the equimolar mixture. A threefold decrease in the degree of synergy was observed with TrCel7B and the catalytic module of CflXyn11A; suggesting an important role played by the carbohydrate-binding module of CflXyn11A (CflXyn11A-CBM) in the observed synergy. Affinity electrophoresis and binding assays showed that CflXyn11A-CBM binds to xylans and to a lesser extent to cellulose. Our results suggest that synergy is more pronounced at early stages of hydrolysis. Furthermore, for the first time it is described that a CBM carried by a xylanase significantly enhances the synergy with a cellulase (threefold increase in synergy).
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Affiliation(s)
- Patricia Pavón-Orozco
- Departamento de Biotecnología y Bioingeniería, CINVESTAV, Av. Instituto Politécnico Nacional No. 2508, CP 07360, México DF, Mexico
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Olver B, Van Dyk JS, Beukes N, Pletschke BI. Synergy between EngE, XynA and ManA from Clostridium cellulovorans on corn stalk, grass and pineapple pulp substrates. 3 Biotech 2011; 1:187-192. [PMID: 22558536 PMCID: PMC3339617 DOI: 10.1007/s13205-011-0011-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2011] [Accepted: 05/24/2011] [Indexed: 11/24/2022] Open
Abstract
The synergistic interaction between various hemi/cellulolytic enzymes has become more important in order to achieve effective and optimal degradation of complex lignocellulose substrates for biofuel production. This study investigated the synergistic effect of three enzymes endoglucanase (EngE), mannanase (ManA) and xylanase (XynA) on the degradation of corn stalk, grass, and pineapple fruit pulp and determined the optimal degree of synergy between combinations of these enzymes. It was established that EngE was essential for degradation of all of the substrates, while the hemicellulases were able to contribute in a synergistic fashion to increase the activity on these substrates. Maximum specific activity and degree of synergy on the corn stalk and grass was found with EngE:XynA in a ratio of 75:25%, with a specific activity of 41.1 U/mg protein and a degree of synergy of 6.3 for corn stalk, and 44.1 U/mg protein and 3.4 for grass, respectively. The pineapple fruit pulp was optimally digested using a ManA:EngE combination in a 50:50% ratio; the specific activity and degree of synergy achieved were 52.4 U/mg protein and 2.7, respectively. This study highlights the importance of hemicellulases for the synergistic degradation of complex lignocellulose. The inclusion of a mannanase in an enzyme consortium for biomass degradation should be examined further as this study suggests that it may play an important, although mostly overlooked, role in the synergistic saccharification of lignocellulose.
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Affiliation(s)
- B. Olver
- Department of Biochemistry, Microbiology and Biotechnology, Rhodes University, Grahamstown, 6139 South Africa
| | - J. S. Van Dyk
- Department of Biochemistry, Microbiology and Biotechnology, Rhodes University, Grahamstown, 6139 South Africa
| | - N. Beukes
- Department of Biochemistry, Microbiology and Biotechnology, Rhodes University, Grahamstown, 6139 South Africa
| | - B. I. Pletschke
- Department of Biochemistry, Microbiology and Biotechnology, Rhodes University, Grahamstown, 6139 South Africa
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Lime pretreatment of sugar beet pulp and evaluation of synergy between ArfA, ManA and XynA from Clostridium cellulovorans on the pretreated substrate. 3 Biotech 2011; 1:151-159. [PMID: 22611526 PMCID: PMC3339618 DOI: 10.1007/s13205-011-0019-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Accepted: 07/16/2011] [Indexed: 11/20/2022] Open
Abstract
Sugar beet pulp (SBP) is a waste product from the sugar beet industry and could be used as a potential biomass feedstock for second generation biofuel technology. Pretreatment of SBP with ‘slake lime’ (calcium hydroxide) was investigated using a 23 factorial design and the factors examined included lime loading, temperature and time. The pretreatment was evaluated for its ability to enhance enzymatic degradation using a combination of three hemicellulases, namely ArfA (an arabinofuranosidase), ManA (an endo-mannanase) and XynA (an endo-xylanase) from C. cellulovorans to determine the conditions under which optimal activity was facilitated. Optimal pretreatment conditions were found to be 0.4 g lime/g SBP, with 36 h digestion at 40 °C. The synergistic interactions between ArfA, ManA and XynA from C. cellulovorans were subsequently investigated on the pretreated SBP. The highest degree of synergy was observed at a protein ratio of 75% ArfA to 25% ManA, with a specific activity of 2.9 U/g protein. However, the highest activity was observed at 4.2 U/g protein at 100% ArfA. This study demonstrated that lime treatment enhanced enzymatic hydrolysis of SBP. The ArfA was the most effective hemicellulase for release of sugars from pretreated SBP, but the synergy with the ManA indicated that low levels of mannan in SBP were probably masking the access of the ArfA to its substrate. XynA displayed no synergy with the other two hemicellulases, indicating that the xylan in the SBP was not hampering the access of ArfA or ManA to their substrates and was not closely associated with the mannan and arabinan in the SBP.
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Beukes N, Pletschke BI. Effect of alkaline pre-treatment on enzyme synergy for efficient hemicellulose hydrolysis in sugarcane bagasse. BIORESOURCE TECHNOLOGY 2011; 102:5207-5213. [PMID: 21353533 DOI: 10.1016/j.biortech.2011.01.090] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 01/25/2011] [Accepted: 01/29/2011] [Indexed: 05/30/2023]
Abstract
This aim of this study was to investigate the effect of ammonium hydroxide (NH(4)OH) and sodium hydroxide (NaOH) pre-treatment on the digestibility of sugarcane bagasse (SCB) by hemicellulase action. It was found that pre-treatment of SCB with NH(4)OH removed a larger percentage of the SCB lignin and effectively increased SCB digestibility 13.13 fold. The greatest amount of reducing sugar (1194.88 μmol/min) and largest degree of synergy (2.85) was obtained using a combination of two enzymes (25% ManA and 75% XynA) with NH(4)OH pre-treated SCB. In this study, NH(4)OH therefore appeared to be a more effective pre-treatment step for subsequent hydrolysis by hemicellulases.
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Affiliation(s)
- Natasha Beukes
- Department of Biochemistry, Microbiology and Biotechnology, Rhodes University, Grahamstown 6140, South Africa
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Wongwilaiwalin S, Rattanachomsri U, Laothanachareon T, Eurwilaichitr L, Igarashi Y, Champreda V. Analysis of a thermophilic lignocellulose degrading microbial consortium and multi-species lignocellulolytic enzyme system. Enzyme Microb Technol 2010. [DOI: 10.1016/j.enzmictec.2010.07.013] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Beukes N, Pletschke BI. Effect of lime pre-treatment on the synergistic hydrolysis of sugarcane bagasse by hemicellulases. BIORESOURCE TECHNOLOGY 2010; 101:4472-4478. [PMID: 20156678 DOI: 10.1016/j.biortech.2010.01.081] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2009] [Revised: 01/14/2010] [Accepted: 01/19/2010] [Indexed: 05/28/2023]
Abstract
Agricultural crop wastes are typically lignocellulosic in composition and thus partially recalcitrant to enzymatic degradation. The recalcitrant nature of plant biomass and the inability to obtain complete enzymatic hydrolysis has led to the establishment of various pre-treatment strategies. Alkaline pre-treatments increase the accessibility of the exposed surface to enzymatic hydrolysis through the removal of acetyl and uronic acid substituents on hemicelluloses. Unlike the use of steam and acid pre-treatments, alkaline pre-treatments (e.g. lime) solubilise lignin and a small percentage of the hemicelluloses. The most common alkaline pre-treatments that are employed make use of sodium hydroxide and lime. This study compared the synergistic degradation of un-treated and lime pre-treated sugarcane bagasse using cellulosomal and non-cellulosomal hemicellulases as free enzymes. The enzyme combination of 37.5% ArfA and 62.5% ManA produced the highest amount of reducing sugar of 91.834 micromol/min for the degradation of un-treated bagasse. This enzyme combination produced a degree of synergy of 1.87. The free enzymes displayed an approximately 6-fold increase in the enzyme activity, i.e. the total amount of reducing sugar released (593.65 micromol/min) with the enzyme combination of 37.5% ArfA, 25% ManA and 37.5% XynA for the lime pre-treated substrate and a degree of synergy of 2.14. To conclude, this study indicated that pre-treating the sugarcane bagasse is essential, in order to increase the efficiency of lignocellulose enzymatic hydrolysis by disruption of the lignin sheath, that the lime pre-treatment did not have any dramatic effect on the synergistic relationship between the free enzymes, and that time may play an important role in the establishment of synergistic relationships between enzymes.
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Affiliation(s)
- Natasha Beukes
- Department of Biochemistry, Microbiology and Biotechnology, Rhodes University, Grahamstown 6140, South Africa
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