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Oliveira DM. Glucuronic acid: not just another brick in the cell wall. THE NEW PHYTOLOGIST 2023; 238:8-10. [PMID: 36862529 DOI: 10.1111/nph.18804] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Affiliation(s)
- Dyoni M Oliveira
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 71, 9052, Ghent, Belgium
- VIB Center for Plant Systems Biology, Technologiepark 71, 9052, Ghent, Belgium
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2
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Derba-Maceluch M, Mitra M, Hedenström M, Liu X, Gandla ML, Barbut FR, Abreu IN, Donev EN, Urbancsok J, Moritz T, Jönsson LJ, Tsang A, Powlowski J, Master ER, Mellerowicz EJ. Xylan glucuronic acid side chains fix suberin-like aliphatic compounds to wood cell walls. THE NEW PHYTOLOGIST 2023; 238:297-312. [PMID: 36600379 DOI: 10.1111/nph.18712] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Accepted: 11/30/2022] [Indexed: 06/17/2023]
Abstract
Wood is the most important repository of assimilated carbon in the biosphere, in the form of large polymers (cellulose, hemicelluloses including glucuronoxylan, and lignin) that interactively form a composite, together with soluble extractives including phenolic and aliphatic compounds. Molecular interactions among these compounds are not fully understood. We have targeted the expression of a fungal α-glucuronidase to the wood cell wall of aspen (Populus tremula L. × tremuloides Michx.) and Arabidopsis (Arabidopsis thaliana (L.) Heynh), to decrease contents of the 4-O-methyl glucuronopyranose acid (mGlcA) substituent of xylan, to elucidate mGlcA's functions. The enzyme affected the content of aliphatic insoluble cell wall components having composition similar to suberin, which required mGlcA for binding to cell walls. Such suberin-like compounds have been previously identified in decayed wood, but here, we show their presence in healthy wood of both hardwood and softwood species. By contrast, γ-ester bonds between mGlcA and lignin were insensitive to cell wall-localized α-glucuronidase, supporting the intracellular formation of these bonds. These findings challenge the current view of the wood cell wall composition and reveal a novel function of mGlcA substituent of xylan in fastening of suberin-like compounds to cell wall. They also suggest an intracellular initiation of lignin-carbohydrate complex assembly.
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Affiliation(s)
- Marta Derba-Maceluch
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, 901 83, Umeå, Sweden
| | - Madhusree Mitra
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, 901 83, Umeå, Sweden
| | | | - Xiaokun Liu
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, 901 83, Umeå, Sweden
| | | | - Félix R Barbut
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, 901 83, Umeå, Sweden
| | - Ilka N Abreu
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, 901 83, Umeå, Sweden
| | - Evgeniy N Donev
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, 901 83, Umeå, Sweden
| | - János Urbancsok
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, 901 83, Umeå, Sweden
| | - Thomas Moritz
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, 901 83, Umeå, Sweden
| | - Leif J Jönsson
- Department of Chemistry, Umeå University, 901 87, Umeå, Sweden
| | - Adrian Tsang
- Centre for Structural and Functional Genomics, Concordia University, Montreal, QC, H4B 1R6, Canada
| | - Justin Powlowski
- Centre for Structural and Functional Genomics, Concordia University, Montreal, QC, H4B 1R6, Canada
| | - Emma R Master
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, ON, M5S 3E5, Canada
| | - Ewa J Mellerowicz
- Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, 901 83, Umeå, Sweden
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3
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Benatti ALT, Polizeli MDLTDM. Lignocellulolytic Biocatalysts: The Main Players Involved in Multiple Biotechnological Processes for Biomass Valorization. Microorganisms 2023; 11:microorganisms11010162. [PMID: 36677454 PMCID: PMC9864444 DOI: 10.3390/microorganisms11010162] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 12/11/2022] [Accepted: 12/26/2022] [Indexed: 01/10/2023] Open
Abstract
Human population growth, industrialization, and globalization have caused several pressures on the planet's natural resources, culminating in the severe climate and environmental crisis which we are facing. Aiming to remedy and mitigate the impact of human activities on the environment, the use of lignocellulolytic enzymes for biofuel production, food, bioremediation, and other various industries, is presented as a more sustainable alternative. These enzymes are characterized as a group of enzymes capable of breaking down lignocellulosic biomass into its different monomer units, making it accessible for bioconversion into various products and applications in the most diverse industries. Among all the organisms that produce lignocellulolytic enzymes, microorganisms are seen as the primary sources for obtaining them. Therefore, this review proposes to discuss the fundamental aspects of the enzymes forming lignocellulolytic systems and the main microorganisms used to obtain them. In addition, different possible industrial applications for these enzymes will be discussed, as well as information about their production modes and considerations about recent advances and future perspectives in research in pursuit of expanding lignocellulolytic enzyme uses at an industrial scale.
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Deralia PK, Jensen A, Felby C, Thygesen LG. Chemistry of lignin and hemicellulose structures interacts with hydrothermal pretreatment severity and affects cellulose conversion. Biotechnol Prog 2021; 37:e3189. [PMID: 34176230 DOI: 10.1002/btpr.3189] [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: 10/10/2020] [Revised: 06/06/2021] [Accepted: 06/23/2021] [Indexed: 11/09/2022]
Abstract
Understanding of how the plant cell walls of different plant species respond to pretreatment can help improve saccharification in bioconversion processes. Here, we studied the chemical and structural modifications in lignin and hemicellulose in hydrothermally pretreated poplar and wheat straw using wet chemistry and 2D heteronuclear single quantum coherence nuclear magnetic resonance (NMR) and their effects on cellulose conversion. Increased pretreatment severity reduced the levels of β─O─4 linkages with concomitant relatively increased levels of β─5 and β─β structures in the NMR spectra. β─5 structures appeared at medium and high severities for wheat straw while only β─β structures were observed at all pretreatment severities for poplar. These structural differences accounted for the differences in cellulose conversion for these biomasses at different severities. Changes in the hemicellulose component include a complete removal of arabinosyl and 4-O-methyl glucuronosyl substituents at low and medium pretreatment severities while acetyl groups were found to be relatively resistant toward hydrothermal pretreatment. This illustrates the importance of these groups, rather than xylan content, in the detrimental role of xylan in cellulose saccharification and helps explain the higher poplar recalcitrance compared to wheat straw. The results point toward the need for both enzyme preparation development and pretreatment technologies to target specific plant species.
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Affiliation(s)
- Parveen Kumar Deralia
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Frederiksberg, Denmark
| | - Anders Jensen
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Frederiksberg, Denmark
| | - Claus Felby
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Frederiksberg, Denmark
| | - Lisbeth Garbrecht Thygesen
- Department of Geosciences and Natural Resource Management, University of Copenhagen, Frederiksberg, Denmark
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5
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Expression of Cell Wall-Modifying Enzymes in Aspen for Improved Lignocellulose Processing. Methods Mol Biol 2020. [PMID: 32617934 DOI: 10.1007/978-1-0716-0621-6_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Wood is an important source of biomass for materials and chemicals, and a target for genetic engineering of its properties for different applications or for research. Wood properties can be altered by using different enzymes acting on cell wall polymers postsynthetically in cell walls. This approach allows for a precise polymer structure modification thanks to the specificity of enzymes used. Such enzymes can originate from all kinds of organisms, or even be modified in a desired way for novel attributes. Here we present a general strategy for expressing a microbial enzyme in aspen and targeting it to cell wall, using an example of fungal glucuronoyl esterase. We describe methods of vector cloning, plant transformation, transgenic line selection and multiplication, testing for the presence of enzymatic activity in different cell compartments, and finally the method of plant transferring from sterile culture to the greenhouse conditions.
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6
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Alonso-Serra J, Safronov O, Lim KJ, Fraser-Miller SJ, Blokhina OB, Campilho A, Chong SL, Fagerstedt K, Haavikko R, Helariutta Y, Immanen J, Kangasjärvi J, Kauppila TJ, Lehtonen M, Ragni L, Rajaraman S, Räsänen RM, Safdari P, Tenkanen M, Yli-Kauhaluoma JT, Teeri TH, Strachan CJ, Nieminen K, Salojärvi J. Tissue-specific study across the stem reveals the chemistry and transcriptome dynamics of birch bark. THE NEW PHYTOLOGIST 2019; 222:1816-1831. [PMID: 30724367 DOI: 10.1111/nph.15725] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 01/25/2019] [Indexed: 05/09/2023]
Abstract
Tree bark is a highly specialized array of tissues that plays important roles in plant protection and development. Bark tissues develop from two lateral meristems; the phellogen (cork cambium) produces the outermost stem-environment barrier called the periderm, while the vascular cambium contributes with phloem tissues. Although bark is diverse in terms of tissues, functions and species, it remains understudied at higher resolution. We dissected the stem of silver birch (Betula pendula) into eight major tissue types, and characterized these by a combined transcriptomics and metabolomics approach. We further analyzed the varying bark types within the Betulaceae family. The two meristems had a distinct contribution to the stem transcriptomic landscape. Furthermore, inter- and intraspecies analyses illustrated the unique molecular profile of the phellem. We identified multiple tissue-specific metabolic pathways, such as the mevalonate/betulin biosynthesis pathway, that displayed differential evolution within the Betulaceae. A detailed analysis of suberin and betulin biosynthesis pathways identified a set of underlying regulators and highlighted the important role of local, small-scale gene duplication events in the evolution of metabolic pathways. This work reveals the transcriptome and metabolic diversity among bark tissues and provides insights to its development and evolution, as well as its biotechnological applications.
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Affiliation(s)
- Juan Alonso-Serra
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, 00014, Helsinki, Finland
- Viikki Plant Science Centre, University of Helsinki, Helsinki, 00014, Helsinki, Finland
- Institute of Biotechnology, University of Helsinki, Helsinki, 00014, Helsinki, Finland
| | - Omid Safronov
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, 00014, Helsinki, Finland
- Viikki Plant Science Centre, University of Helsinki, Helsinki, 00014, Helsinki, Finland
| | - Kean-Jin Lim
- Viikki Plant Science Centre, University of Helsinki, Helsinki, 00014, Helsinki, Finland
- Department of Agricultural Sciences, University of Helsinki, Helsinki, 00014, Helsinki, Finland
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Lin'an, 311300, Hangzhou, China
| | - Sara J Fraser-Miller
- Drug Research Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, 00014, Helsinki, Finland
- The Dodd-Walls Centre for Photonic and Quantum Technologies, Department of Chemistry, University of Otago, 9054, Dunedin, New Zealand
| | - Olga B Blokhina
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, 00014, Helsinki, Finland
- Viikki Plant Science Centre, University of Helsinki, Helsinki, 00014, Helsinki, Finland
| | - Ana Campilho
- Research Center in Biodiversity and Genetic Resources, Department of Biology, Faculty of Sciences, University of Porto, 4485-661, Porto, Portugal
| | - Sun-Li Chong
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Lin'an, 311300, Hangzhou, China
- Department of Food and Nutrition, University of Helsinki, 00014, Helsinki, Finland
| | - Kurt Fagerstedt
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, 00014, Helsinki, Finland
- Viikki Plant Science Centre, University of Helsinki, Helsinki, 00014, Helsinki, Finland
| | - Raisa Haavikko
- Drug Research Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, 00014, Helsinki, Finland
| | - Ykä Helariutta
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, 00014, Helsinki, Finland
- Viikki Plant Science Centre, University of Helsinki, Helsinki, 00014, Helsinki, Finland
- Institute of Biotechnology, University of Helsinki, Helsinki, 00014, Helsinki, Finland
- Sainsbury Laboratory, University of Cambridge, Cambridge, CB2 1LR, UK
| | - Juha Immanen
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, 00014, Helsinki, Finland
- Viikki Plant Science Centre, University of Helsinki, Helsinki, 00014, Helsinki, Finland
- Institute of Biotechnology, University of Helsinki, Helsinki, 00014, Helsinki, Finland
- Natural Resources Institute Finland (Luke), 00710, Helsinki, Finland
| | - Jaakko Kangasjärvi
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, 00014, Helsinki, Finland
- Viikki Plant Science Centre, University of Helsinki, Helsinki, 00014, Helsinki, Finland
| | - Tiina J Kauppila
- Drug Research Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, 00014, Helsinki, Finland
| | - Mari Lehtonen
- Laboratory Center, Finnish Environment Institute (SYKE), 00790, Helsinki, Finland
| | - Laura Ragni
- ZMBP-Center for Plant Molecular Biology, University of Tübingen, D-72076, Tübingen, Germany
| | - Sitaram Rajaraman
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, 00014, Helsinki, Finland
- Viikki Plant Science Centre, University of Helsinki, Helsinki, 00014, Helsinki, Finland
| | - Riikka-Marjaana Räsänen
- Drug Research Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, 00014, Helsinki, Finland
| | - Pezhman Safdari
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, 00014, Helsinki, Finland
- Viikki Plant Science Centre, University of Helsinki, Helsinki, 00014, Helsinki, Finland
| | - Maija Tenkanen
- Department of Food and Nutrition, University of Helsinki, 00014, Helsinki, Finland
| | - Jari T Yli-Kauhaluoma
- Drug Research Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, 00014, Helsinki, Finland
| | - Teemu H Teeri
- Viikki Plant Science Centre, University of Helsinki, Helsinki, 00014, Helsinki, Finland
- Department of Agricultural Sciences, University of Helsinki, Helsinki, 00014, Helsinki, Finland
| | - Clare J Strachan
- Drug Research Program, Division of Pharmaceutical Chemistry and Technology, Faculty of Pharmacy, University of Helsinki, 00014, Helsinki, Finland
| | - Kaisa Nieminen
- Natural Resources Institute Finland (Luke), 00710, Helsinki, Finland
| | - Jarkko Salojärvi
- Organismal and Evolutionary Biology Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, 00014, Helsinki, Finland
- Viikki Plant Science Centre, University of Helsinki, Helsinki, 00014, Helsinki, Finland
- School of Biological Sciences, Nanyang Technological University, 637551, Singapore, Singapore
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, 637551, Singapore, Singapore
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7
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Wierzbicki MP, Maloney V, Mizrachi E, Myburg AA. Xylan in the Middle: Understanding Xylan Biosynthesis and Its Metabolic Dependencies Toward Improving Wood Fiber for Industrial Processing. FRONTIERS IN PLANT SCIENCE 2019; 10:176. [PMID: 30858858 PMCID: PMC6397879 DOI: 10.3389/fpls.2019.00176] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Accepted: 02/04/2019] [Indexed: 05/14/2023]
Abstract
Lignocellulosic biomass, encompassing cellulose, lignin and hemicellulose in plant secondary cell walls (SCWs), is the most abundant source of renewable materials on earth. Currently, fast-growing woody dicots such as Eucalyptus and Populus trees are major lignocellulosic (wood fiber) feedstocks for bioproducts such as pulp, paper, cellulose, textiles, bioplastics and other biomaterials. Processing wood for these products entails separating the biomass into its three main components as efficiently as possible without compromising yield. Glucuronoxylan (xylan), the main hemicellulose present in the SCWs of hardwood trees carries chemical modifications that are associated with SCW composition and ultrastructure, and affect the recalcitrance of woody biomass to industrial processing. In this review we highlight the importance of xylan properties for industrial wood fiber processing and how gaining a greater understanding of xylan biosynthesis, specifically xylan modification, could yield novel biotechnology approaches to reduce recalcitrance or introduce novel processing traits. Altering xylan modification patterns has recently become a focus of plant SCW studies due to early findings that altered modification patterns can yield beneficial biomass processing traits. Additionally, it has been noted that plants with altered xylan composition display metabolic differences linked to changes in precursor usage. We explore the possibility of using systems biology and systems genetics approaches to gain insight into the coordination of SCW formation with other interdependent biological processes. Acetyl-CoA, s-adenosylmethionine and nucleotide sugars are precursors needed for xylan modification, however, the pathways which produce metabolic pools during different stages of fiber cell wall formation still have to be identified and their co-regulation during SCW formation elucidated. The crucial dependence on precursor metabolism provides an opportunity to alter xylan modification patterns through metabolic engineering of one or more of these interdependent pathways. The complexity of xylan biosynthesis and modification is currently a stumbling point, but it may provide new avenues for woody biomass engineering that are not possible for other biopolymers.
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Affiliation(s)
| | | | | | - Alexander A. Myburg
- Department of Biochemistry, Genetics and Microbiology, Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
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8
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Pawar PMA, Ratke C, Balasubramanian VK, Chong SL, Gandla ML, Adriasola M, Sparrman T, Hedenström M, Szwaj K, Derba-Maceluch M, Gaertner C, Mouille G, Ezcurra I, Tenkanen M, Jönsson LJ, Mellerowicz EJ. Downregulation of RWA genes in hybrid aspen affects xylan acetylation and wood saccharification. THE NEW PHYTOLOGIST 2017; 214:1491-1505. [PMID: 28257170 DOI: 10.1111/nph.14489] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Accepted: 01/23/2017] [Indexed: 05/17/2023]
Abstract
High acetylation of angiosperm wood hinders its conversion to sugars by glycoside hydrolases, subsequent ethanol fermentation and (hence) its use for biofuel production. We studied the REDUCED WALL ACETYLATION (RWA) gene family of the hardwood model Populus to evaluate its potential for improving saccharification. The family has two clades, AB and CD, containing two genes each. All four genes are expressed in developing wood but only RWA-A and -B are activated by master switches of the secondary cell wall PtNST1 and PtMYB21. Histochemical analysis of promoter::GUS lines in hybrid aspen (Populus tremula × tremuloides) showed activation of RWA-A and -B promoters in the secondary wall formation zone, while RWA-C and -D promoter activity was diffuse. Ectopic downregulation of either clade reduced wood xylan and xyloglucan acetylation. Suppressing both clades simultaneously using the wood-specific promoter reduced wood acetylation by 25% and decreased acetylation at position 2 of Xylp in the dimethyl sulfoxide-extracted xylan. This did not affect plant growth but decreased xylose and increased glucose contents in the noncellulosic monosaccharide fraction, and increased glucose and xylose yields of wood enzymatic hydrolysis without pretreatment. Both RWA clades regulate wood xylan acetylation in aspen and are promising targets to improve wood saccharification.
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Affiliation(s)
- Prashant Mohan-Anupama Pawar
- Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå, S-901 83, Sweden
| | - Christine Ratke
- Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå, S-901 83, Sweden
| | - Vimal K Balasubramanian
- Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå, S-901 83, Sweden
| | - Sun-Li Chong
- Department of Food and Environmental Sciences, University of Helsinki, PO Box 27, FI-Helsinki, 00014, Finland
| | | | - Mathilda Adriasola
- School of Biotechnology, Royal Institute of Technology (KTH), AlbaNova University Centre, SE-106 91, Stockholm, Sweden
| | - Tobias Sparrman
- Department of Chemistry, Umeå University, Umeå, S-901 87, Sweden
| | | | - Klaudia Szwaj
- Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå, S-901 83, Sweden
| | - Marta Derba-Maceluch
- Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå, S-901 83, Sweden
| | - Cyril Gaertner
- Institut Jean-Pierre Bourgin, UMR1318 INRA-AgroParisTech, ERL3559 CNRS, Saclay Plant Sciences, INRA, Versailles, 78026, France
| | - Gregory Mouille
- Institut Jean-Pierre Bourgin, UMR1318 INRA-AgroParisTech, ERL3559 CNRS, Saclay Plant Sciences, INRA, Versailles, 78026, France
| | - Ines Ezcurra
- School of Biotechnology, Royal Institute of Technology (KTH), AlbaNova University Centre, SE-106 91, Stockholm, Sweden
| | - Maija Tenkanen
- Department of Food and Environmental Sciences, University of Helsinki, PO Box 27, FI-Helsinki, 00014, Finland
| | - Leif J Jönsson
- Department of Chemistry, Umeå University, Umeå, S-901 87, Sweden
| | - Ewa J Mellerowicz
- Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå, S-901 83, Sweden
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9
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Lyczakowski JJ, Wicher KB, Terrett OM, Faria-Blanc N, Yu X, Brown D, Krogh KBRM, Dupree P, Busse-Wicher M. Removal of glucuronic acid from xylan is a strategy to improve the conversion of plant biomass to sugars for bioenergy. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:224. [PMID: 28932265 PMCID: PMC5606085 DOI: 10.1186/s13068-017-0902-1] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 09/07/2017] [Indexed: 05/04/2023]
Abstract
BACKGROUND Plant lignocellulosic biomass can be a source of fermentable sugars for the production of second generation biofuels and biochemicals. The recalcitrance of this plant material is one of the major obstacles in its conversion into sugars. Biomass is primarily composed of secondary cell walls, which is made of cellulose, hemicelluloses and lignin. Xylan, a hemicellulose, binds to the cellulose microfibril and is hypothesised to form an interface between lignin and cellulose. Both softwood and hardwood xylan carry glucuronic acid side branches. As xylan branching may be important for biomass recalcitrance and softwood is an abundant, non-food competing, source of biomass it is important to investigate how conifer xylan is synthesised. RESULTS Here, we show using Arabidopsis gux mutant biomass that removal of glucuronosyl substitutions of xylan can allow 30% more glucose and over 700% more xylose to be released during saccharification. Ethanol yields obtained through enzymatic saccharification and fermentation of gux biomass were double those obtained for non-mutant material. Our analysis of additional xylan branching mutants demonstrates that absence of GlcA is unique in conferring the reduced recalcitrance phenotype. As in hardwoods, conifer xylan is branched with GlcA. We use transcriptomic analysis to identify conifer enzymes that might be responsible for addition of GlcA branches onto xylan in industrially important softwood. Using a combination of in vitro and in vivo activity assays, we demonstrate that a white spruce (Picea glauca) gene, PgGUX, encodes an active glucuronosyl transferase. Glucuronic acid introduced by PgGUX reduces the sugar release of Arabidopsis gux mutant biomass to wild-type levels indicating that it can fulfil the same biological function as native glucuronosylation. CONCLUSION Removal of glucuronic acid from xylan results in the largest increase in release of fermentable sugars from Arabidopsis plants that grow to the wild-type size. Additionally, plant material used in this work did not undergo any chemical pretreatment, and thus increased monosaccharide release from gux biomass can be achieved without the use of environmentally hazardous chemical pretreatment procedures. Therefore, the identification of a gymnosperm enzyme, likely to be responsible for softwood xylan glucuronosylation, provides a mutagenesis target for genetically improved forestry trees.
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Affiliation(s)
- Jan J. Lyczakowski
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW UK
- Natural Material Innovation Centre, University of Cambridge, 1 Scroope Terrace, Cambridge, CB2 1PX UK
- OpenPlant Synthetic Biology Research Centre, Department of Plant Sciences, University of Cambridge, Downing Site, Cambridge, CB2 3EA UK
| | - Krzysztof B. Wicher
- The Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QN UK
- Ossianix, Stevenage Bioscience Catalyst, Gunnels Wood Rd, Stevenage, Hertfordshire, SG1 2FX UK
| | - Oliver M. Terrett
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW UK
| | - Nuno Faria-Blanc
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW UK
| | - Xiaolan Yu
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW UK
| | - David Brown
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW UK
- Present Address: Shell Global Solutions International BV, Lange Kleiweg 40, 2288 GK Rijswijk, The Netherlands
| | - Kristian B. R. M. Krogh
- Department of Protein Biochemistry and Stability, Novozymes A/S, Krogshøjvej 36, 2880 Bagsværd, Denmark
| | - Paul Dupree
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW UK
- Natural Material Innovation Centre, University of Cambridge, 1 Scroope Terrace, Cambridge, CB2 1PX UK
- OpenPlant Synthetic Biology Research Centre, Department of Plant Sciences, University of Cambridge, Downing Site, Cambridge, CB2 3EA UK
| | - Marta Busse-Wicher
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QW UK
- Natural Material Innovation Centre, University of Cambridge, 1 Scroope Terrace, Cambridge, CB2 1PX UK
- OpenPlant Synthetic Biology Research Centre, Department of Plant Sciences, University of Cambridge, Downing Site, Cambridge, CB2 3EA UK
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