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Sivan P, Heinonen E, Escudero L, Gandla ML, Jiménez-Quero A, Jönsson LJ, Mellerowicz EJ, Vilaplana F. Unraveling the unique structural motifs of glucuronoxylan from hybrid aspen wood. Carbohydr Polym 2024; 343:122434. [PMID: 39174079 DOI: 10.1016/j.carbpol.2024.122434] [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: 05/07/2024] [Revised: 06/11/2024] [Accepted: 06/24/2024] [Indexed: 08/24/2024]
Abstract
Xylan is a fundamental structural polysaccharide in plant secondary cell walls and a valuable resource for biorefinery applications. Deciphering the molecular motifs of xylans that mediate their interaction with cellulose and lignin is fundamental to understand the structural integrity of plant cell walls and to design lignocellulosic materials. In the present study, we investigated the pattern of acetylation and glucuronidation substitution in hardwood glucuronoxylan (GX) extracted from aspen wood using subcritical water and alkaline conditions. Enzymatic digestions of GX with β-xylanases from glycosyl hydrolase (GH) families GH10, GH11 and GH30 generated xylo-oligosaccharides with controlled structures amenable for mass spectrometric glycan sequencing. We identified the occurrence of intramolecular motifs in aspen GX with block repeats of even glucuronidation (every 2 xylose units) and consecutive glucuronidation, which are unique features for hardwood xylans. The acetylation pattern of aspen GX shows major domains with evenly-spaced decorations, together with minor stretches of highly acetylated domains. These heterogenous patterns of GX can be correlated with its extractability and with its potential interaction with lignin and cellulose. Our study provides new insights into the molecular structure of xylan in hardwood species, which has fundamental implications for overcoming lignocellulose recalcitrance during biochemical conversion.
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Affiliation(s)
- Pramod Sivan
- Division of Glycoscience, Department of Chemistry, KTH Royal Institute of Technology, AlbaNova University Centre, 106 91 Stockholm, Sweden
| | - Emilia Heinonen
- Division of Glycoscience, Department of Chemistry, KTH Royal Institute of Technology, AlbaNova University Centre, 106 91 Stockholm, Sweden; Wallenberg Wood Science Centre (WWSC), KTH Royal Institute of Technology, 100 44 Stockholm, Sweden
| | - Louis Escudero
- Division of Glycoscience, Department of Chemistry, KTH Royal Institute of Technology, AlbaNova University Centre, 106 91 Stockholm, Sweden
| | | | - Amparo Jiménez-Quero
- Division of Glycoscience, Department of Chemistry, KTH Royal Institute of Technology, AlbaNova University Centre, 106 91 Stockholm, Sweden
| | - Leif J Jönsson
- Department of Chemistry, Umeå University, 901 87 Umeå, Sweden
| | - Ewa J Mellerowicz
- Umeå Plant Science Centre, Swedish University of Agricultural Sciences, Department of Forest Genetics and Plant Physiology, 901 83 Umeå, Sweden
| | - Francisco Vilaplana
- Division of Glycoscience, Department of Chemistry, KTH Royal Institute of Technology, AlbaNova University Centre, 106 91 Stockholm, Sweden; Wallenberg Wood Science Centre (WWSC), KTH Royal Institute of Technology, 100 44 Stockholm, Sweden.
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2
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Zheng B, Zhang L, Zhou Z, Chen S, Chen L, Li Y, Wu A, Li H. Understanding the dynamic evolution of hemicellulose during Pinus taeda L. growth. Int J Biol Macromol 2024; 273:132914. [PMID: 38844290 DOI: 10.1016/j.ijbiomac.2024.132914] [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: 12/05/2023] [Revised: 05/31/2024] [Accepted: 06/03/2024] [Indexed: 06/13/2024]
Abstract
Pinus taeda L. is a fast-growing softwood with significant commercial value. Understanding structural changes in hemicellulose during growth is essential to understanding the biosynthesis processes occurring in the cell walls of this tree. In this study, alkaline extraction is applied to isolate hemicellulose from Pinus taeda L. stem segments of different ages (1, 2, 3, and 4 years old). The results show that the extracted hemicellulose is mainly comprised of O-acetylgalactoglucomannan (GGM) and 4-O-methylglucuronoarabinoxylan (GAX), with the molecular weights and ratios (i.e., GGM:GAX) of GGM and GAX increasing alongside Pinus taeda L. age. Mature Pinus taeda L. hemicellulose is mainly composed of GGM, and the ratio of (mannose:glucose) in the GGM main chain gradually increases from 2.45 to 3.60 with growth, while the galactose substitution of GGM decreases gradually from 21.36% to 14.65%. The acetylation of GGM gradually increases from 0.33 to 0.45 with the acetyl groups mainly substituting into the O-3 position in the mannan. Furthermore, the contents of arabinose and glucuronic acid in GAX gradually decrease with growth. This study can provide useful information to the research in genetic breeding and high-value utilization of Pinus taeda L.
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Affiliation(s)
- Biao Zheng
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China
| | - Liuyang Zhang
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China
| | - Zibin Zhou
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China
| | - Siyi Chen
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China
| | - Luoting Chen
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China
| | - Yuanhua Li
- School of Chemistry and Materials Engineering, Huizhou University, Huizhou 516007, China
| | - Aimin Wu
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China.
| | - Huiling Li
- Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China.
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3
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Martins JR, Llanos JHR, Abe MM, Costa ML, Brienzo M. New blend of renewable bioplastic based on starch and acetylated xylan with high resistance to oil and water vapor. Carbohydr Res 2024; 537:109068. [PMID: 38417199 DOI: 10.1016/j.carres.2024.109068] [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: 10/09/2023] [Revised: 02/17/2024] [Accepted: 02/21/2024] [Indexed: 03/01/2024]
Abstract
Renewable materials of biological origin exhibit attractive properties in relation to traditional plastics, as they can be partially or completely replaced, thereby reducing environmental impacts. Hemicelluloses are a group of polysaccharides that have expanded applications when acetylated. Acetylation can improve the mechanical strength and water vapor barrier properties of xylan-based bioplastics. By partially acetylating xylan in the present study, it was possible to use water as a solvent for the film-forming solution and starch as a second polysaccharide in the formation of bioplastics. Xylan was modified via partial chemical acetylation by varying the reaction time, solvent, and catalyst content. The bioplastics were formed by non-acetylated xylan and acetylated xylan with degrees of substitution (DS) of 0.45 and 0.9, respectively, with starch to form blends using glycerol as a plasticizer. Acetylation with DS 0.45 showed better results in increasing the hydrophilicity of the bioplastic. On the other hand, acetylation influenced the thermal stability of bioplastics, increasing the maximum temperature of the degradation rate from 302 °C to 329 °C and 315 °C, owing to changes in the crystallinity of the polymers. In addition to the modulus of elasticity 2.99 to 290.61 and 274.67 MPa for the non-acetylated bioplastic and the bioplastic with DS of 0.45 and 0.90, respectively. Thus, the films obtained presented suitable physicochemical properties for use in various industrial applications, such as active and intelligent packaging in the food sector.
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Affiliation(s)
- Julia Ribeiro Martins
- Institute for Research in Bioenergy (IPBEN), São Paulo State University (Unesp), 13500-230, Rio Claro, SP, Brazil
| | | | - Mateus Manabu Abe
- Institute for Research in Bioenergy (IPBEN), São Paulo State University (Unesp), 13500-230, Rio Claro, SP, Brazil
| | - Michelle Leali Costa
- Materials and Technology Department, School of Engineering, São Paulo State University (Unesp), Av. Dr. Ariberto Pereira da Cunha 333, Guaratinguetá, 12516-410, Brazil; Lightweight Structures Laboratory (LEL/IPT), Rod. Presidente Dutra, s/n, 137, 8 km - Eugenio de Melo, São José dos Campos, 12247-004, Brazil
| | - Michel Brienzo
- Institute for Research in Bioenergy (IPBEN), São Paulo State University (Unesp), 13500-230, Rio Claro, SP, Brazil.
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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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Zheng B, Yang H, Xu X, Xiang Z, Hong Z, Zheng H, Wu A, Li H. Characterization of hemicellulose in Cunninghamia lanceolata stem during xylogenesis. Int J Biol Macromol 2023; 246:125530. [PMID: 37355061 DOI: 10.1016/j.ijbiomac.2023.125530] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 06/18/2023] [Accepted: 06/21/2023] [Indexed: 06/26/2023]
Abstract
In this study, hemicellulose was isolated from the apical, middle and basal segments of C. lanceolata stem to investigate the dynamic change of its structure during xylogenesis. Results showed that the C. lanceolata hemicellulose is mainly consisted of O-acetylgalactoglucomannan (GGM) which backbone is alternately linked by β-d-mannopyranosyl (Manp) and β-d-glucopyranosyl (Glcp) via (1 → 4)-glycosidic bond, while the side chains are α-d-galactopyranosyl (Galp) and acetyl. In addition, 4-O-methylglucuronoarabinoxylan (GAX) is another dominant structure of C. lanceolata hemicellulose which contains a linear backbone of (1 → 4)-β-d-xylopyranosyl (Xylp) and side chains of 4-O-Me-α-d-glucuronic acid (MeGlcpA) and α-L-arabinofuranose (Araf). The thickness of the cell wall, the ratio of GGM/GAX and the molecular weight of hemicellulose were increased as the extension of growth time. The degree of glycosyl substitutions of xylan and mannan was decreased from 10.34 % (apical) to 8.38 % (basal) and from 15.63 % (apical) to 10.49 % (basal), respectively. However, the total degree of acetylation was enhanced from 0.28 (apical) to 0.37 (basal). Transcriptome analysis showed that genes (CSLA9, IRX9H1, IRX10L, IRX15L, GMGT1, TBL19, TBL25, GUX2, GUX3, GXM1, F8H1 and F8H2) related to hemicellulose biosynthesis are mainly expressed in mature part. This study is of great significance for genetic breeding and high-value utilization of C. lanceolata.
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Affiliation(s)
- Biao Zheng
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou 510642, China; Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China
| | - Haoqiang Yang
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou 510642, China; Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China
| | - Xiaoli Xu
- Instrumental Analysis and Research Center, South China Agricultural University, Guangzhou 510642, China
| | - Zhouyang Xiang
- State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou 510640, China
| | - Zhou Hong
- Research institute of tropical Forestry, Chinese Academy of Forestry, Guangzhou 510520, China
| | - Huiquan Zheng
- Guangdong Provincial Key Laboratory of Silviculture, Protection and Utilization, Guangdong Academy of Forestry, Guangzhou 510520, China.
| | - Aimin Wu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou 510642, China; Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China.
| | - Huiling Li
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, South China Agricultural University, Guangzhou 510642, China; Guangdong Key Laboratory for Innovative Development and Utilization of Forest Plant Germplasm, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou 510642, China.
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Spatial correlation of water distribution and fine structure of arabinoxylans in the developing wheat grain. Carbohydr Polym 2022; 294:119738. [DOI: 10.1016/j.carbpol.2022.119738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Revised: 05/27/2022] [Accepted: 06/12/2022] [Indexed: 11/21/2022]
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7
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Ward NE. Debranching enzymes in corn/soybean meal-based poultry feeds: a review. Poult Sci 2021; 100:765-775. [PMID: 33518131 PMCID: PMC7858153 DOI: 10.1016/j.psj.2020.10.074] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Revised: 07/24/2020] [Accepted: 10/27/2020] [Indexed: 12/25/2022] Open
Abstract
This review discusses the complex nature of the primary nonstarch polysaccharide (NSP) in corn with respect to the merit of debranching enzymes. Celluloses, hemicelluloses, and pectins comprise the 3 major categories of NSP that make up nearly 90% of plant cell walls. Across cereals, the hemicellulose arabinoxylan exists as the primary NSP, followed by cellulose, glucans, and others. Differences in arabinoxylan structure among cereals and cereal fractions are facilitated by cereal type, degree and pattern of substitution along the xylan backbone, phenol content, and cross-linkages. In particular, arabinoxylan (also called glucuronoarabinoxylan) in corn is heavily fortified with substituents, being more populated than in wheat and other cereal grains. Feed-grade xylanases - almost solely of the glycoside hydrolase (GH) 10 and GH 11 families - require at least 2 or 3 contiguous xylose units to be free of attachments to effectively attack the xylan chain. This canopy of attachments, along with a high phenol content and the insoluble nature of corn glucuronoarabinoxylan, confers a significant resistance to xylanase attack. Both in vitro and in vivo studies demonstrate that debranching enzymes appreciably increase xylanase access and fiber degradability by removing these attachments and breaking phenolic linkages. The enzymatic degradation of the highly branched arabinoxylan can facilitate disassembly of other fibers by increasing exposure to pertinent carbohydrases. For cereals, the arabinofuranosidases, α-glucuronidases, and esterases are some of the more germane debranching enzymes. Enzyme composites beyond the simple core mixes of xylanases, cellulases, and glucanases can exploit synergistic benefits generated by this class of enzymes. A broad scope of enzymatic activity in customized mixes can more effectively target the resilient NSP construct of cereal grains in commercial poultry diets, particularly those in corn-based feeds.
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Affiliation(s)
- Nelson E Ward
- Animal Nutrition and Health Group, DSM Nutritional Products Inc., Ringoes, NJ 08551, USA.
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Bio-based films from wheat bran feruloylated arabinoxylan: Effect of extraction technique, acetylation and feruloylation. Carbohydr Polym 2020; 250:116916. [DOI: 10.1016/j.carbpol.2020.116916] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2020] [Revised: 08/04/2020] [Accepted: 08/05/2020] [Indexed: 01/05/2023]
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Wood hemicelluloses exert distinct biomechanical contributions to cellulose fibrillar networks. Nat Commun 2020; 11:4692. [PMID: 32943624 PMCID: PMC7499266 DOI: 10.1038/s41467-020-18390-z] [Citation(s) in RCA: 67] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 08/20/2020] [Indexed: 12/03/2022] Open
Abstract
Hemicelluloses, a family of heterogeneous polysaccharides with complex molecular structures, constitute a fundamental component of lignocellulosic biomass. However, the contribution of each hemicellulose type to the mechanical properties of secondary plant cell walls remains elusive. Here we homogeneously incorporate different combinations of extracted and purified hemicelluloses (xylans and glucomannans) from softwood and hardwood species into self-assembled networks during cellulose biosynthesis in a bacterial model, without altering the morphology and the crystallinity of the cellulose bundles. These composite hydrogels can be therefore envisioned as models of secondary plant cell walls prior to lignification. The incorporated hemicelluloses exhibit both a rigid phase having close interactions with cellulose, together with a flexible phase contributing to the multiscale architecture of the bacterial cellulose hydrogels. The wood hemicelluloses exhibit distinct biomechanical contributions, with glucomannans increasing the elastic modulus in compression, and xylans contributing to a dramatic increase of the elongation at break under tension. These diverging effects cannot be explained solely from the nature of their direct interactions with cellulose, but can be related to the distinct molecular structure of wood xylans and mannans, the multiphase architecture of the hydrogels and the aggregative effects amongst hemicellulose-coated fibrils. Our study contributes to understanding the specific roles of wood xylans and glucomannans in the biomechanical integrity of secondary cell walls in tension and compression and has significance for the development of lignocellulosic materials with controlled assembly and tailored mechanical properties. Hemicelluloses are an essential constituent of plant cell walls, but the individual biomechanical roles remain elusive. Here the authors report on the interaction of wood hemicellulose with bacterial cellulose during deposition and explore the resultant fibrillar architecture and mechanical properties.
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Carvalho DMD, Berglund J, Marchand C, Lindström ME, Vilaplana F, Sevastyanova O. Improving the thermal stability of different types of xylan by acetylation. Carbohydr Polym 2019; 220:132-140. [DOI: 10.1016/j.carbpol.2019.05.063] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Revised: 05/22/2019] [Accepted: 05/22/2019] [Indexed: 12/19/2022]
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Affiliation(s)
- Saina Kishani
- School of Chemical Science and Engineering, Fibre and Polymer Technology, Royal Institute of Technology, Teknikringen 56-58, SE-10044 Stockholm, Sweden
- Wallenberg
Wood
Science Centre (WWSC), Teknikringen 56-58, SE-10044 Stockholm, Sweden
| | - Francisco Vilaplana
- Wallenberg
Wood
Science Centre (WWSC), Teknikringen 56-58, SE-10044 Stockholm, Sweden
- School of Biotechnology, Division of Glycoscience, Royal Institute of Technology, Albanova University Centre, SE-10691 Stockholm, Sweden
| | - Wenyang Xu
- Johan Gadolin Process Chemistry Centre, Laboratory of Wood and Paper Chemistry, Åbo Akademi University, FI-20500 Turku/Åbo, Finland
| | - Chunlin Xu
- Johan Gadolin Process Chemistry Centre, Laboratory of Wood and Paper Chemistry, Åbo Akademi University, FI-20500 Turku/Åbo, Finland
| | - Lars Wågberg
- School of Chemical Science and Engineering, Fibre and Polymer Technology, Royal Institute of Technology, Teknikringen 56-58, SE-10044 Stockholm, Sweden
- Wallenberg
Wood
Science Centre (WWSC), Teknikringen 56-58, SE-10044 Stockholm, Sweden
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12
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Arnling Bååth J, Martínez-Abad A, Berglund J, Larsbrink J, Vilaplana F, Olsson L. Mannanase hydrolysis of spruce galactoglucomannan focusing on the influence of acetylation on enzymatic mannan degradation. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:114. [PMID: 29713374 PMCID: PMC5907293 DOI: 10.1186/s13068-018-1115-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 04/10/2018] [Indexed: 05/14/2023]
Abstract
BACKGROUND Galactoglucomannan (GGM) is the most abundant hemicellulose in softwood, and consists of a backbone of mannose and glucose units, decorated with galactose and acetyl moieties. GGM can be hydrolyzed into fermentable sugars, or used as a polymer in films, gels, and food additives. Endo-β-mannanases, which can be found in the glycoside hydrolase families 5 and 26, specifically cleave the mannan backbone of GGM into shorter oligosaccharides. Information on the activity and specificity of different mannanases on complex and acetylated substrates is still lacking. The aim of this work was to evaluate and compare the modes of action of two mannanases from Cellvibrio japonicus (CjMan5A and CjMan26A) on a variety of mannan substrates, naturally and chemically acetylated to varying degrees, including naturally acetylated spruce GGM. Both enzymes were evaluated in terms of cleavage patterns and their ability to accommodate acetyl substitutions. RESULTS CjMan5A and CjMan26A demonstrated different substrate preferences on mannan substrates with distinct backbone and decoration structures. CjMan5A action resulted in higher amounts of mannotriose and mannotetraose than that of CjMan26A, which mainly generated mannose and mannobiose as end products. Mass spectrometric analysis of products from the enzymatic hydrolysis of spruce GGM revealed that an acetylated hexotriose was the shortest acetylated oligosaccharide produced by CjMan5A, whereas CjMan26A generated acetylated hexobiose as well as diacetylated oligosaccharides. A low degree of native acetylation did not significantly inhibit the enzymatic action. However, a high degree of chemical acetylation resulted in decreased hydrolyzability of mannan substrates, where reduced substrate solubility seemed to reduce enzyme activity. CONCLUSIONS Our findings demonstrate that the two mannanases from C. japonicus have different cleavage patterns on linear and decorated mannan polysaccharides, including the abundant and industrially important resource spruce GGM. CjMan26A released higher amounts of fermentable sugars suitable for biofuel production, while CjMan5A, producing higher amounts of oligosaccharides, could be a good candidate for the production of oligomeric platform chemicals and food additives. Furthermore, chemical acetylation of mannan polymers was found to be a potential strategy for limiting the biodegradation of mannan-containing materials.
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Affiliation(s)
- Jenny Arnling Bååth
- Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden
- Wallenberg Wood Science Center, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Antonio Martínez-Abad
- Division of Glycoscience, Department of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, 100 44 Stockholm, Sweden
- Present Address: Department of Analytical Chemistry, Nutrition and Food Sciences, University of Alicante, 03690 Alicante, Spain
| | - Jennie Berglund
- Wallenberg Wood Science Center, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, 100 44 Stockholm, Sweden
| | - Johan Larsbrink
- Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden
- Wallenberg Wood Science Center, Chalmers University of Technology, 412 96 Gothenburg, Sweden
| | - Francisco Vilaplana
- Division of Glycoscience, Department of Chemistry, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, 100 44 Stockholm, Sweden
- Wallenberg Wood Science Center, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, 100 44 Stockholm, Sweden
| | - Lisbeth Olsson
- Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, 412 96 Gothenburg, Sweden
- Wallenberg Wood Science Center, Chalmers University of Technology, 412 96 Gothenburg, Sweden
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