1
|
Sousa J, Santos-Pereira C, Gomes JS, Costa ÂMA, Santos AO, Franco-Duarte R, Linhares JMM, Sousa SF, Silvério SC, Rodrigues LR. Heterologous expression and structure prediction of a xylanase identified from a compost metagenomic library. Appl Microbiol Biotechnol 2024; 108:329. [PMID: 38727750 PMCID: PMC11087322 DOI: 10.1007/s00253-024-13169-4] [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: 01/10/2024] [Revised: 04/22/2024] [Accepted: 05/02/2024] [Indexed: 05/13/2024]
Abstract
Xylanases are key biocatalysts in the degradation of the β-1,4-glycosidic linkages in the xylan backbone of hemicellulose. These enzymes are potentially applied in a wide range of bioprocessing industries under harsh conditions. Metagenomics has emerged as powerful tools for the bioprospection and discovery of interesting bioactive molecules from extreme ecosystems with unique features, such as high temperatures. In this study, an innovative combination of function-driven screening of a compost metagenomic library and automatic extraction of halo areas with in-house MATLAB functions resulted in the identification of a promising clone with xylanase activity (LP4). The LP4 clone proved to be an effective xylanase producer under submerged fermentation conditions. Sequence and phylogenetic analyses revealed that the xylanase, Xyl4, corresponded to an endo-1,4-β-xylanase belonging to glycosyl hydrolase family 10 (GH10). When xyl4 was expressed in Escherichia coli BL21(DE3), the enzyme activity increased about 2-fold compared to the LP4 clone. To get insight on the interaction of the enzyme with the substrate and establish possible strategies to improve its activity, the structure of Xyl4 was predicted, refined, and docked with xylohexaose. Our data unveiled, for the first time, the relevance of the amino acids Glu133 and Glu238 for catalysis, and a close inspection of the catalytic site suggested that the replacement of Phe316 by a bulkier Trp may improve Xyl4 activity. Our current findings contribute to enhancing the catalytic performance of Xyl4 towards industrial applications. KEY POINTS: • A GH10 endo-1,4-β-xylanase (Xyl4) was isolated from a compost metagenomic library • MATLAB's in-house functions were developed to identify the xylanase-producing clones • Computational analysis showed that Glu133 and Glu238 are crucial residues for catalysis.
Collapse
Affiliation(s)
- Joana Sousa
- CEB - Centre of Biological Engineering, Universidade do Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - Cátia Santos-Pereira
- CEB - Centre of Biological Engineering, Universidade do Minho, Campus de Gualtar, 4710-057, Braga, Portugal
- LABBELS - Associate Laboratory, Braga/Guimarães, Portugal
| | - Joana S Gomes
- CEB - Centre of Biological Engineering, Universidade do Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - Ângela M A Costa
- CEB - Centre of Biological Engineering, Universidade do Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - Andréia O Santos
- CEB - Centre of Biological Engineering, Universidade do Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - Ricardo Franco-Duarte
- CBMA - Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
- IB-S - Institute of Science and Innovation for Bio-Sustainability, University of Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - João M M Linhares
- Physics Center of Minho and Porto Universities (CF-UM-UP), Universidade do Minho, Campus de Gualtar, 4710-057, Braga, Portugal
| | - Sérgio F Sousa
- LAQV/REQUIMTE BioSIM - Department of Biomedicine, Faculty of Medicine, University of Porto, 4200-319, Porto, Portugal
| | - Sara C Silvério
- CEB - Centre of Biological Engineering, Universidade do Minho, Campus de Gualtar, 4710-057, Braga, Portugal.
- LABBELS - Associate Laboratory, Braga/Guimarães, Portugal.
| | - Lígia R Rodrigues
- CEB - Centre of Biological Engineering, Universidade do Minho, Campus de Gualtar, 4710-057, Braga, Portugal
- LABBELS - Associate Laboratory, Braga/Guimarães, Portugal
| |
Collapse
|
2
|
Salzano F, Aulitto M, Fiorentino G, Cannella D, Peeters E, Limauro D. A novel endo-1,4-β-xylanase from Alicyclobacillus mali FL18: Biochemical characterization and its synergistic action with β-xylosidase in hemicellulose deconstruction. Int J Biol Macromol 2024; 264:130550. [PMID: 38432267 DOI: 10.1016/j.ijbiomac.2024.130550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 02/20/2024] [Accepted: 02/28/2024] [Indexed: 03/05/2024]
Abstract
A novel endo-1,4-β-xylanase-encoding gene was identified in Alicyclobacillus mali FL18 and the recombinant protein, named AmXyn, was purified and biochemically characterized. The monomeric enzyme worked optimally at pH 6.6 and 80 °C on beechwood xylan with a specific activity of 440.00 ± 0.02 U/mg and a good catalytic efficiency (kcat/KM = 91.89 s-1mLmg-1). In addition, the enzyme did not display any activity on cellulose, suggesting a possible application in paper biobleaching processes. To develop an enzymatic mixture for xylan degradation, the association between AmXyn and the previously characterized β-xylosidase AmβXyl, deriving from the same microorganism, was assessed. The two enzymes had similar temperature and pH optima and showed the highest degree of synergy when AmXyn and AmβXyl were added sequentially to beechwood xylan, making this mixture cost-competitive and suitable for industrial use. Therefore, this enzymatic cocktail was also employed for the hydrolysis of wheat bran residue. TLC and HPAEC-PAD analyses revealed a high conversion rate to xylose (91.56 %), placing AmXyn and AmβXyl among the most promising biocatalysts for the saccharification of agricultural waste.
Collapse
Affiliation(s)
- Flora Salzano
- Dipartimento di Biologia, Università di Napoli Federico II, Complesso Universitario Monte S. Angelo, Via Cinthia, 80126 Naples, Italy
| | - Martina Aulitto
- Dipartimento di Biologia, Università di Napoli Federico II, Complesso Universitario Monte S. Angelo, Via Cinthia, 80126 Naples, Italy
| | - Gabriella Fiorentino
- Dipartimento di Biologia, Università di Napoli Federico II, Complesso Universitario Monte S. Angelo, Via Cinthia, 80126 Naples, Italy
| | - David Cannella
- PhotoBiocatalysis Unit, Biomass Transformation lab - BTL, and Crop production and Biostimulation Lab - CPBL, Universitè libre de Brussels, ULB, Belgium
| | - Eveline Peeters
- Department of Bioengineering Sciences Faculty of Sciences and Bioengineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium
| | - Danila Limauro
- Dipartimento di Biologia, Università di Napoli Federico II, Complesso Universitario Monte S. Angelo, Via Cinthia, 80126 Naples, Italy.
| |
Collapse
|
3
|
Wei H, Liu M, Zhang K, Li J, Ouyang X. Heterologous expression of family GH11 Aspergillus niger xylanase B (AnXylB11) in Pichia pastoris and competitive inhibition by riceXIP: An experimental and simulation study. Colloids Surf B Biointerfaces 2022; 220:112907. [DOI: 10.1016/j.colsurfb.2022.112907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 10/03/2022] [Accepted: 10/07/2022] [Indexed: 11/27/2022]
|
4
|
Tang K, Cui Y, Xiao J, Ding M, Chao H, Wu J, Han Z, Liu J, Li X, Yan D. Molecular cloning and characterization of a novel xylanase from Microbacterium imperiale YD-01. J Food Biochem 2021; 45:e13988. [PMID: 34730252 DOI: 10.1111/jfbc.13988] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 09/25/2021] [Accepted: 10/13/2021] [Indexed: 11/27/2022]
Abstract
Xylaneses are very common xylanolytic enzymes, which are widely used in food, papermaking, and other industries. In this study, a xylanase-encoding gene xyn1923, which encodes a protein of 1352 amino acids, was identified through the whole genome analysis of Microbacterium imperiale YD-01. Bioinformatics analysis showed that Xyn1923 only had maximum similarity of 37% with the reported xylanase from Alkalihalobacillus halodurans C-125, indicating that Xyn1923 was a novel xylanase. The enzymatic properties of Xyn1923 were systematically analyzed after purification. The results showed that the specific activity of the enzyme was 10.582 ± 0.413 U/mg, while the optimum pH and temperature of the enzyme were 7.0 and 70°C, respectively. The enzyme is stable in the pH range of 6.0-9.0, and the enzyme activity could maintain more than 85% of the original activity after 16 hr incubation at pH 9.0. The enzyme activity is relatively stable in the range of 30-60°C, and its enzyme activity could maintain more than 89% of the original activity after treatment at 60°C for 30 min. Low concentrations (≤1 mM) of Co2+ , Ba2+ , Fe2+ , and Fe3+ metal ions exerted a stimulatory effect on the activity of Xyn1923. And in contrast, high concentrations (≥2 mM) of the above metal ions inhibit the activity of Xyn1923. Mg2+ , Ag+ , Cu2+ , Ca2+ , Mn2+ , and Pb2+ ions showed a negative effect on the activity of Xyn1923. Enzyme kinetic studies showed that Km and Vmax values for xylan were 7.842 ± 0.538 mg/ml and 15.208 ± 0.822 U/mg, respectively. Xyn1923 was found to be a weakly alkaline thermophilic xylanase through an enzymatic property analysis. PRACTICAL APPLICATIONS: Xylanases are widely used in food and feed, biofuels, papermaking, and other industries. However, their use is limited by poor performance under the conditions of pH and temperature. Therefore, the discovery of xylanases with the capability of working efficiently at alkaline pH and high temperature is the priority for its industrial applications. In this study, a novel xylanase-encoding gene xyn1923 from Microbacterium imperiale YD-01 was cloned and heterologously expressed in Escherichia coli. Enzymatic properties of this novel xylanase were investigated, indicating that the robust thermal stability and alkali resistance of Xyn1923 make it a potential candidate for the food and paper industries.
Collapse
Affiliation(s)
- Keqin Tang
- Hubei Key Laboratory of Animal Nutrition and Feed Science, Wuhan Polytechnic University, Wuhan, China.,School of life science and technology, Wuhan Polytechnic University, Wuhan, China
| | - Yin Cui
- School of life science and technology, Wuhan Polytechnic University, Wuhan, China
| | - Jingyi Xiao
- City University of Hong Kong, Kowloon, China
| | - Mengyao Ding
- School of life science and technology, Wuhan Polytechnic University, Wuhan, China
| | - Hongjun Chao
- School of life science and technology, Wuhan Polytechnic University, Wuhan, China
| | - Jing Wu
- School of life science and technology, Wuhan Polytechnic University, Wuhan, China
| | - Zhenggang Han
- School of life science and technology, Wuhan Polytechnic University, Wuhan, China
| | - Jun Liu
- School of life science and technology, Wuhan Polytechnic University, Wuhan, China
| | - Xin Li
- School of life science and technology, Wuhan Polytechnic University, Wuhan, China
| | - Dazhong Yan
- Hubei Key Laboratory of Animal Nutrition and Feed Science, Wuhan Polytechnic University, Wuhan, China.,School of life science and technology, Wuhan Polytechnic University, Wuhan, China
| |
Collapse
|
5
|
Teze D, Zhao J, Wiemann M, Kazi ZGA, Lupo R, Zeuner B, Vuillemin M, Rønne ME, Carlström G, Duus JØ, Sanejouand YH, O'Donohue MJ, Nordberg Karlsson E, Fauré R, Stålbrand H, Svensson B. Rational Enzyme Design without Structural Knowledge: A Sequence-Based Approach for Efficient Generation of Transglycosylases. Chemistry 2021; 27:10323-10334. [PMID: 33914359 DOI: 10.1002/chem.202100110] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Indexed: 12/22/2022]
Abstract
Glycobiology is dogged by the relative scarcity of synthetic, defined oligosaccharides. Enzyme-catalysed glycosylation using glycoside hydrolases is feasible but is hampered by the innate hydrolytic activity of these enzymes. Protein engineering is useful to remedy this, but it usually requires prior structural knowledge of the target enzyme, and/or relies on extensive, time-consuming screening and analysis. Here, a straightforward strategy that involves rational rapid in silico analysis of protein sequences is described. The method pinpoints 6-12 single-mutant candidates to improve transglycosylation yields. Requiring very little prior knowledge of the target enzyme other than its sequence, the method is generic and procures catalysts for the formation of glycosidic bonds involving various d/l-, α/β-pyranosides or furanosides, and exo or endo action. Moreover, mutations validated in one enzyme can be transposed to others, even distantly related enzymes.
Collapse
Affiliation(s)
- David Teze
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, building 224, DK-2800, Kongens Lyngby, Denmark
| | - Jiao Zhao
- Toulouse Biotechnology Institute, Université de Toulouse, CNRS, INRAE, INSA, 135 avenue de Rangueil, 31077, Toulouse CEDEX 04, France
| | - Mathias Wiemann
- Department of Biochemistry and Structural Biology, Lund University, 221 00, Lund, Sweden
| | - Zubaida G A Kazi
- Department of Chemistry, Lund University, PO Box 124, 22100, Lund, Sweden
| | - Rossana Lupo
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, building 224, DK-2800, Kongens Lyngby, Denmark
| | - Birgitte Zeuner
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, building 224, DK-2800, Kongens Lyngby, Denmark
| | - Marlène Vuillemin
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, building 224, DK-2800, Kongens Lyngby, Denmark
| | - Mette E Rønne
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, building 224, DK-2800, Kongens Lyngby, Denmark
| | - Göran Carlström
- Department of Chemistry, Lund University, PO Box 124, 22100, Lund, Sweden
| | - Jens Ø Duus
- Department of Chemistry, Technical University of Denmark, Kemitorvet, bulding 207, DK-2800, Kongens Lyngby, Denmark
| | - Yves-Henri Sanejouand
- UFIP, UMR 6286, Université de Nantes, CNRS, 2, chemin de la Houssiniere, Nantes, France
| | - Michael J O'Donohue
- Toulouse Biotechnology Institute, Université de Toulouse, CNRS, INRAE, INSA, 135 avenue de Rangueil, 31077, Toulouse CEDEX 04, France
| | | | - Régis Fauré
- Toulouse Biotechnology Institute, Université de Toulouse, CNRS, INRAE, INSA, 135 avenue de Rangueil, 31077, Toulouse CEDEX 04, France
| | - Henrik Stålbrand
- Department of Biochemistry and Structural Biology, Lund University, 221 00, Lund, Sweden
| | - Birte Svensson
- Department of Biotechnology and Biomedicine, Technical University of Denmark, Søltofts Plads, building 224, DK-2800, Kongens Lyngby, Denmark
| |
Collapse
|
6
|
Meng Q, Wang S, Niu Q, Yan H, Li Q. The influences of illite/smectite clay on lignocellulose decomposition and maturation process revealed by metagenomics analysis during cattle manure composting. WASTE MANAGEMENT (NEW YORK, N.Y.) 2021; 127:1-9. [PMID: 33910097 DOI: 10.1016/j.wasman.2021.04.033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 03/21/2021] [Accepted: 04/12/2021] [Indexed: 06/12/2023]
Abstract
The purpose of this study was to analyze the effects of illite/smectite clay (I/S) on lignocellulosic degradation and humification process via metagenomics analysis during cattle manure composting. The test group (TG) with 10% I/S and the reference group (RG) were established. The results indicated that the addition of I/S made the degradation rate of cellulose, hemicellulose and lignin in TG (1.56%, 29.01%, 19.95%) was higher than that in RG (1.16%, 17.24%, 13.14%). Compared with RG, the abundance values of AA2, AA10, GH1 and GH10 in TG increased by 15.18%, 29.28%, 31.08%, 21.65%, respectively. Meanwhile, humic substance (HS) content was increased by 3.49% and 7.16% during RG and TG composting. Furthermore, the microbial community in TG changed, in which the relative abundance of Actinobacteria increased and Proteobacteria decreased. Redundancy analysis (RDA) showed that the temperature was positively correlated with the abundance of AA2, AA10, GH1 and GH10, whereas the organic matter content was negatively correlated. Overall, adding I/S to the composting could stimulate microbial activity, promote the degradation of lignocellulose and humification process.
Collapse
Affiliation(s)
- Qingran Meng
- School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China
| | - Susu Wang
- School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China
| | - Qiuqi Niu
- School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China
| | - Hailong Yan
- School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China
| | - Qunliang Li
- School of Chemistry and Chemical Engineering, Guangxi University, Nanning 530004, China.
| |
Collapse
|
7
|
From by- to bioproducts: selection of a nanofiltration membrane for biotechnological xylitol purification and process optimization. FOOD AND BIOPRODUCTS PROCESSING 2021. [DOI: 10.1016/j.fbp.2020.10.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
8
|
Characterization of a novel xylanase from an extreme temperature hot spring metagenome for xylooligosaccharide production. Appl Microbiol Biotechnol 2020; 104:4889-4901. [DOI: 10.1007/s00253-020-10562-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 03/12/2020] [Accepted: 03/20/2020] [Indexed: 10/24/2022]
|
9
|
Velasco J, Oliva B, Mulinari EJ, Quintero LP, da Silva Lima A, Gonçalves AL, Gonçalves TA, Damasio A, Squina FM, Ferreira Milagres AM, Abdella A, Wilkins MR, Segato F. Heterologous expression and functional characterization of a GH10 endoxylanase from Aspergillus fumigatus var. niveus with potential biotechnological application. BIOTECHNOLOGY REPORTS (AMSTERDAM, NETHERLANDS) 2019; 24:e00382. [PMID: 31799141 PMCID: PMC6881608 DOI: 10.1016/j.btre.2019.e00382] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/28/2019] [Revised: 08/26/2019] [Accepted: 09/26/2019] [Indexed: 10/25/2022]
Abstract
Xylanases decrease the xylan content in pretreated biomass releasing it from hemicellulose, thus improving the accessibility of cellulose for cellulases. In this work, an endo-β-1,4-xylanase from Aspergillus fumigatus var. niveus (AFUMN-GH10) was successfully expressed. The structural analysis and biochemical characterization showed this AFUMN-GH10 does not contain a carbohydrate-binding module. The enzyme retained its activity in a pH range from 4.5 to 7.0, with an optimal temperature at 60 °C. AFUMN-GH10 showed the highest activity in beechwood xylan. The mode of action of AFUMN-GH10 was investigated by hydrolysis of APTS-labeled xylohexaose, which resulted in xylotriose and xylobiose as the main products. AFUMN-GH10 released 27% of residual xylan from hydrothermally-pretreated corn stover and 14% of residual xylan from hydrothermally-pretreated sugarcane bagasse. The results showed that environmentally friendly pretreatment followed by enzymatic hydrolysis with AFUMN-GH10 in low concentration is a suitable method to remove part of residual and recalcitrant hemicellulose from biomass.
Collapse
Affiliation(s)
- Josman Velasco
- Department of Biotechnology, Lorena School of Engineering, University of São Paulo, Lorena, SP, Brazil
| | - Bianca Oliva
- Department of Biotechnology, Lorena School of Engineering, University of São Paulo, Lorena, SP, Brazil
| | - Evandro José Mulinari
- Department of Physics and Applied Sciences, São Carlos Institute of Physics, University of São Paulo, São Carlos, SP, Brazil
| | - Leidy Patricia Quintero
- Department of Biotechnology, Lorena School of Engineering, University of São Paulo, Lorena, SP, Brazil
| | - Awana da Silva Lima
- Department of Biotechnology, Lorena School of Engineering, University of São Paulo, Lorena, SP, Brazil
| | - Aline Larissa Gonçalves
- Department of Biotechnology, Lorena School of Engineering, University of São Paulo, Lorena, SP, Brazil
| | - Thiago Augusto Gonçalves
- Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas, Campinas, SP, Brazil
- Programa de Processos Tecnológicos e Ambientais, Universidade de Sorocaba, Sorocaba, SP, Brazil
| | - André Damasio
- Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas, Campinas, SP, Brazil
| | - Fabio Marcio Squina
- Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas, Campinas, SP, Brazil
- Programa de Processos Tecnológicos e Ambientais, Universidade de Sorocaba, Sorocaba, SP, Brazil
| | | | - Asmaa Abdella
- Department of Biological Systems Engineering, University of Nebraska-Lincoln, Lincoln, NE, USA
- Industrial Agricultural Products Center, University of Nebraska-Lincoln, Lincoln, NE, USA
- Department of Industrial Biotechnology, Genetic Engineering and Biotechnology Research Institute, University of Sadat City, Sadat City, Egypt
| | - Mark R. Wilkins
- Department of Biological Systems Engineering, University of Nebraska-Lincoln, Lincoln, NE, USA
- Industrial Agricultural Products Center, University of Nebraska-Lincoln, Lincoln, NE, USA
- Department of Food Science and Technology, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Fernando Segato
- Department of Biotechnology, Lorena School of Engineering, University of São Paulo, Lorena, SP, Brazil
| |
Collapse
|
10
|
Biochemical characterization and low-resolution SAXS shape of a novel GH11 exo-1,4-β-xylanase identified in a microbial consortium. Appl Microbiol Biotechnol 2019; 103:8035-8049. [PMID: 31407040 DOI: 10.1007/s00253-019-10033-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Revised: 07/15/2019] [Accepted: 07/15/2019] [Indexed: 10/26/2022]
Abstract
Biotechnologies that aim to produce renewable fuels, chemicals, and bioproducts from residual ligno(hemi)cellulosic biomass mostly rely on enzymatic depolymerization of plant cell walls (PCW). This process requires an arsenal of diverse enzymes, including xylanases, which synergistically act on the hemicellulose, reducing the long and complex xylan chains to oligomers and simple sugars. Thus, xylanases play a crucial role in PCW depolymerization. Until recently, the largest xylanase family, glycoside hydrolase family 11 (GH11) has been exclusively represented by endo-catalytic β-1,4- and β-1,3-xylanases. Analysis of a metatranscriptome library from a microbial lignocellulose community resulted in the identification of an unusual exo-acting GH11 β-1,4-xylanase (MetXyn11). Detailed characterization has been performed on recombinant MetXyn11 including determination of its low-resolution small-angle X-ray scattering (SAXS) molecular envelope in solution. Our results reveal that MetXyn11 is a monomeric globular enzyme that liberates xylobiose from heteroxylans as the only product. MetXyn11 has an optimal activity in a pH range from 6 to 9 and an optimal temperature of 50 °C. The enzyme maintained above 65% of its original activity in the pH range 5 to 6 after being incubated for 72 h at 50 °C. Addition of the enzyme to a commercial enzymatic cocktail (CelicCtec3) promoted a significant increase of enzymatic hydrolysis yields of hydrothermally pretreated sugarcane bagasse (16% after 24 h of hydrolysis).
Collapse
|
11
|
Characterizing a Halo-Tolerant GH10 Xylanase from Roseithermus sacchariphilus Strain RA and Its CBM-Truncated Variant. Int J Mol Sci 2019; 20:ijms20092284. [PMID: 31075847 PMCID: PMC6539836 DOI: 10.3390/ijms20092284] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2019] [Revised: 04/22/2019] [Accepted: 05/07/2019] [Indexed: 11/26/2022] Open
Abstract
A halo-thermophilic bacterium, Roseithermus sacchariphilus strain RA (previously known as Rhodothermaceae bacterium RA), was isolated from a hot spring in Langkawi, Malaysia. A complete genome analysis showed that the bacterium harbors 57 glycoside hydrolases (GHs), including a multi-domain xylanase (XynRA2). The full-length XynRA2 of 813 amino acids comprises a family 4_9 carbohydrate-binding module (CBM4_9), a family 10 glycoside hydrolase catalytic domain (GH10), and a C-terminal domain (CTD) for type IX secretion system (T9SS). This study aims to describe the biochemical properties of XynRA2 and the effects of CBM truncation on this xylanase. XynRA2 and its CBM-truncated variant (XynRA2ΔCBM) was expressed, purified, and characterized. The purified XynRA2 and XynRA2ΔCBM had an identical optimum temperature at 70 °C, but different optimum pHs of 8.5 and 6.0 respectively. Furthermore, XynRA2 retained 94% and 71% of activity at 4.0 M and 5.0 M NaCl respectively, whereas XynRA2ΔCBM showed a lower activity (79% and 54%). XynRA2 exhibited a turnover rate (kcat) of 24.8 s−1, but this was reduced by 40% for XynRA2ΔCBM. Both the xylanases hydrolyzed beechwood xylan predominantly into xylobiose, and oat-spelt xylan into a mixture of xylo-oligosaccharides (XOs). Collectively, this work suggested CBM4_9 of XynRA2 has a role in enzyme performance.
Collapse
|
12
|
Ariaeenejad S, Hosseini E, Maleki M, Kavousi K, Moosavi-Movahedi AA, Salekdeh GH. Identification and characterization of a novel thermostable xylanase from camel rumen metagenome. Int J Biol Macromol 2019; 126:1295-1302. [DOI: 10.1016/j.ijbiomac.2018.12.041] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 11/19/2018] [Accepted: 12/02/2018] [Indexed: 11/25/2022]
|