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Ristinmaa AS, Korotkova E, Arntzen MØ, G H Eijsink V, Xu C, Sundberg A, Hasani M, Larsbrink J. Analyses of long-term fungal degradation of spruce bark reveals varying potential for catabolism of polysaccharides and extractive compounds. BIORESOURCE TECHNOLOGY 2024; 402:130768. [PMID: 38697367 DOI: 10.1016/j.biortech.2024.130768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 04/26/2024] [Accepted: 04/29/2024] [Indexed: 05/05/2024]
Abstract
The bark represents the outer protective layer of trees. It contains high concentrations of antimicrobial extractives, in addition to regular wood polymers. It represents a huge underutilized side stream in forestry, but biotechnological valorization is hampered by a lack of knowledge on microbial bark degradation. Many fungi are efficient lignocellulose degraders, and here, spruce bark degradation by five species, Dichomitus squalens, Rhodonia placenta, Penicillium crustosum, Trichoderma sp. B1, and Trichoderma reesei, was mapped, by continuously analyzing chemical changes in the bark over six months. The study reveals how fungi from different phyla degrade bark using diverse strategies, regarding both wood polymers and extractives, where toxic resin acids were degraded by Basidiomycetes but unmodified/tolerated by Ascomycetes. Proteome analyses of the white-rot D. squalens revealed several proteins, with both known and unknown functions, that were specifically upregulated during growth on bark. This knowledge can accelerate improved utilization of an abundant renewable resource.
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Affiliation(s)
- Amanda S Ristinmaa
- Chalmers University of Technology, Department of Life Sciences, Division of Industrial Biotechnology, SE-412 96 Gothenburg, Sweden
| | - Ekaterina Korotkova
- Åbo Akademi University, Laboratory of Natural Materials Technology, FI-20500 Åbo, Finland
| | - Magnus Ø Arntzen
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), NO-1433 Ås, Norway
| | - Vincent G H Eijsink
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences (NMBU), NO-1433 Ås, Norway
| | - Chunlin Xu
- Åbo Akademi University, Laboratory of Natural Materials Technology, FI-20500 Åbo, Finland
| | - Anna Sundberg
- Åbo Akademi University, Laboratory of Natural Materials Technology, FI-20500 Åbo, Finland
| | - Merima Hasani
- Department Chemistry and Chemical Engineering, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden; Wallenberg Wood Science Center, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden
| | - Johan Larsbrink
- Chalmers University of Technology, Department of Life Sciences, Division of Industrial Biotechnology, SE-412 96 Gothenburg, Sweden; Wallenberg Wood Science Center, Chalmers University of Technology, SE-412 96 Gothenburg, Sweden.
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Chaudhari AA, Sharma AM, Rastogi L, Dewangan BP, Sharma R, Singh D, Sah RK, Das S, Bhattacharjee S, Mellerowicz EJ, Pawar PAM. Modifying lignin composition and xylan O-acetylation induces changes in cell wall composition, extractability, and digestibility. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2024; 17:73. [PMID: 38822388 PMCID: PMC11141020 DOI: 10.1186/s13068-024-02513-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Accepted: 05/01/2024] [Indexed: 06/03/2024]
Abstract
BACKGROUND Lignin and xylan are important determinants of cell wall structure and lignocellulosic biomass digestibility. Genetic manipulations that individually modify either lignin or xylan structure improve polysaccharide digestibility. However, the effects of their simultaneous modifications have not been explored in a similar context. Here, both individual and combinatorial modification in xylan and lignin was studied by analysing the effect on plant cell wall properties, biotic stress responses and integrity sensing. RESULTS Arabidopsis plant co-harbouring mutation in FERULATE 5-HYDROXYLASE (F5H) and overexpressing Aspergillus niger acetyl xylan esterase (35S:AnAXE1) were generated and displayed normal growth attributes with intact xylem architecture. This fah1-2/35S:AnAXE1 cross was named as hyper G lignin and hypoacetylated (HrGHypAc) line. The HrGHypAc plants showed increased crystalline cellulose content with enhanced digestibility after chemical and enzymatic pre-treatment. Moreover, both parents and HrGHypAc without and after pre-treating with glucuronyl esterase and alpha glucuronidase exhibited an increase in xylose release after xylanase digestion as compared to wild type. The de-pectinated fraction in HrGHypAc displayed elevated levels of xylan and cellulose. Furthermore, the transcriptomic analysis revealed differential expression in cell wall biosynthetic, transcription factors and wall-associated kinases genes implying the role of lignin and xylan modification on cellular regulatory processes. CONCLUSIONS Simultaneous modification in xylan and lignin enhances cellulose content with improved saccharification efficiency. These modifications loosen cell wall complexity and hence resulted in enhanced xylose and xylobiose release with or without pretreatment after xylanase digestion in both parent and HrGHypAc. This study also revealed that the disruption of xylan and lignin structure is possible without compromising either growth and development or defense responses against Pseudomonas syringae infection.
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Affiliation(s)
- Aniket Anant Chaudhari
- Regional Centre for Biotechnology, Laboratory of Plant Cell Wall Biology, NCR Biotech Science, Cluster 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad-121001, Haryana, India
| | - Anant Mohan Sharma
- Regional Centre for Biotechnology, Laboratory of Plant Cell Wall Biology, NCR Biotech Science, Cluster 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad-121001, Haryana, India
| | - Lavi Rastogi
- Regional Centre for Biotechnology, Laboratory of Plant Cell Wall Biology, NCR Biotech Science, Cluster 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad-121001, Haryana, India
| | - Bhagwat Prasad Dewangan
- Regional Centre for Biotechnology, Laboratory of Plant Cell Wall Biology, NCR Biotech Science, Cluster 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad-121001, Haryana, India
| | - Raunak Sharma
- Regional Centre for Biotechnology, Laboratory of Plant Cell Wall Biology, NCR Biotech Science, Cluster 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad-121001, Haryana, India
| | - Deepika Singh
- Regional Centre for Biotechnology, Laboratory of Plant Cell Wall Biology, NCR Biotech Science, Cluster 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad-121001, Haryana, India
| | - Rajan Kumar Sah
- Regional Centre for Biotechnology, Laboratory of Plant Cell Wall Biology, NCR Biotech Science, Cluster 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad-121001, Haryana, India
| | - Shouvik Das
- Regional Centre for Biotechnology, Laboratory of Plant Cell Wall Biology, NCR Biotech Science, Cluster 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad-121001, Haryana, India
| | - Saikat Bhattacharjee
- Regional Centre for Biotechnology, Laboratory of Plant Cell Wall Biology, NCR Biotech Science, Cluster 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad-121001, Haryana, India
| | - Ewa J Mellerowicz
- Department of Forest Genetics and Plant Physiology, Umea Plant Science Centre, Swedish University of Agricultural Sciences, Umea, Sweden
| | - Prashant Anupama-Mohan Pawar
- Regional Centre for Biotechnology, Laboratory of Plant Cell Wall Biology, NCR Biotech Science, Cluster 3rd Milestone, Faridabad-Gurgaon Expressway, Faridabad-121001, Haryana, India.
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Carbonaro M, Mazurkewich S, Fiorentino G, Lo Leggio L, Larsbrink J. Exploration of three Dyadobacter fermentans enzymes uncovers molecular activity determinants in CE15. Appl Microbiol Biotechnol 2024; 108:335. [PMID: 38747981 PMCID: PMC11096219 DOI: 10.1007/s00253-024-13175-6] [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: 02/01/2024] [Revised: 04/29/2024] [Accepted: 05/04/2024] [Indexed: 05/18/2024]
Abstract
Glucuronoyl esterases (GEs) are serine-type hydrolase enzymes belonging to carbohydrate esterase family 15 (CE15), and they play a central role in the reduction of recalcitrance in plant cell walls by cleaving ester linkages between glucuronoxylan and lignin in lignocellulose. Recent studies have suggested that bacterial CE15 enzymes are more heterogeneous in terms of sequence, structure, and substrate preferences than their fungal counterparts. However, the sequence space of bacterial GEs has still not been fully explored, and further studies on diverse enzymes could provide novel insights into new catalysts of biotechnological interest. To expand our knowledge on this family of enzymes, we investigated three unique CE15 members encoded by Dyadobacter fermentans NS114T, a Gram-negative bacterium found endophytically in maize/corn (Zea mays). The enzymes are dissimilar, sharing ≤ 39% sequence identity to each other' and were considerably different in their activities towards synthetic substrates. Combined analysis of their primary sequences and structural predictions aided in establishing hypotheses regarding specificity determinants within CE15, and these were tested using enzyme variants attempting to shift the activity profiles. Together, the results expand our existing knowledge of CE15, shed light into the molecular determinants defining specificity, and support the recent thesis that diverse GEs encoded by a single microorganism may have evolved to fulfil different physiological functions. KEY POINTS: • D. fermentans encodes three CE15 enzymes with diverse sequences and specificities • The Region 2 inserts in bacterial GEs may directly influence enzyme activity • Rational amino acid substitutions improved the poor activity of the DfCE15A enzyme.
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Affiliation(s)
- Miriam Carbonaro
- Department of Biology, University of Naples Federico II, 80126, Naples, Italy
| | - Scott Mazurkewich
- Wallenberg Wood Science Center, Division of Industrial Biotechnology, Department of Life Sciences, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden.
| | | | - Leila Lo Leggio
- Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100, Copenhagen, Denmark
| | - Johan Larsbrink
- Wallenberg Wood Science Center, Division of Industrial Biotechnology, Department of Life Sciences, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden.
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Czerwiec Q, Chabbert B, Crônier D, Kurek B, Rakotoarivonina H. Combined hemicellulolytic and phenoloxidase activities of Thermobacillus xylanilyticus enable growth on lignin-rich substrates and the release of phenolic molecules. BIORESOURCE TECHNOLOGY 2024; 397:130507. [PMID: 38423483 DOI: 10.1016/j.biortech.2024.130507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Revised: 02/26/2024] [Accepted: 02/26/2024] [Indexed: 03/02/2024]
Abstract
Major challenge in biorefineries is the use of all lignocellulosic components, particularly lignins. In this study, Thermobacillus xylanilyliticus grew on kraft lignin, steam-exploded and native wheat straws produced different sets of phenoloxidases and xylanases, according to the substrate. After growth, limited lignin structural modifications, mainly accompanied by a decrease in phenolic acids was observed by Nuclear Magnetic Resonance spectroscopy. The depletion of p-coumaric acid, vanillin and p-hydroxybenzaldehyde combined to vanillin production in the culture media indicated that the bacterium can transform some phenolic compounds. Proteomic approaches allowed the identification of 29 to 33 different hemicellulases according to the substrates. Twenty oxidoreductases were differentially expressed between kraft lignin and steam-exploded wheat straw. These oxidoreductases may be involved in lignin and aromatic compound utilization and detoxification. This study highlights the potential value of Thermobacillus xylanilyticus and its enzymes in the simultaneous valorization of hemicellulose and phenolic compounds from lignocelluloses.
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Affiliation(s)
- Quentin Czerwiec
- Université de Reims Champagne-Ardenne, INRAE, FARE, UMR A 614, Reims, France; Université de Reims Champagne-Ardenne, INRAE, FARE, UMR A 614, AFERE, Reims, France.
| | - Brigitte Chabbert
- Université de Reims Champagne-Ardenne, INRAE, FARE, UMR A 614, Reims, France.
| | - David Crônier
- Université de Reims Champagne-Ardenne, INRAE, FARE, UMR A 614, Reims, France.
| | - Bernard Kurek
- Université de Reims Champagne-Ardenne, INRAE, FARE, UMR A 614, Reims, France.
| | - Harivony Rakotoarivonina
- Université de Reims Champagne-Ardenne, INRAE, FARE, UMR A 614, Reims, France; Université de Reims Champagne-Ardenne, INRAE, FARE, UMR A 614, AFERE, Reims, France.
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Franzén CJ, Olsson L, Johansen KS. The lignocellulosic biorefinery concept is sound: a commentary on Zhao et al. Trends Biotechnol 2024; 42:395-396. [PMID: 38129215 DOI: 10.1016/j.tibtech.2023.12.005] [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: 12/09/2023] [Accepted: 12/11/2023] [Indexed: 12/23/2023]
Abstract
In the opinion paper by Zhao et al. 'Making the biochemical conversion of lignocellulose more robust', the authors claim that '…lignocellulose biorefinery is conceptually wrong'. In response, we argue that this claim itself has already been proved wrong by several companies.
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Affiliation(s)
- Carl Johan Franzén
- Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, 412 96 Gothenburg, Sweden
| | - Lisbeth Olsson
- Division of Industrial Biotechnology, Department of Biology and Biological Engineering, Chalmers University of Technology, Kemivägen 10, 412 96 Gothenburg, Sweden
| | - Katja Salomon Johansen
- Department of Geosciences and Natural Resource Management, Copenhagen University, DK-1958 Frederiksberg, Denmark.
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Perna V, Agger JW. Transesterification with CE15 glucuronoyl esterase from Cerrena unicolor reveals substrate preferences. Biotechnol Lett 2024; 46:107-114. [PMID: 38150097 PMCID: PMC10787888 DOI: 10.1007/s10529-023-03456-x] [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: 06/26/2023] [Revised: 11/21/2023] [Accepted: 11/25/2023] [Indexed: 12/28/2023]
Abstract
PURPOSE Glucuronoyl esterases (GE, family CE15) catalyse the cleavage of ester linkages in lignin-carbohydrate complexes (LCCs), and this study demonstrate how transesterification reactions with a fungal GE from Cerrena unicolor (CuGE) can reveal the enzyme's preference for the alcohol-part of the ester-bond. METHODS This alcohol-preference relates to where the ester-LCCs are located on the lignin molecule, and has consequences for how the enzymes potentially interact with lignin. It is unknown exactly what the enzymes prefer; either the α-benzyl or the γ-benzyl position. By providing the enzyme with a donor substrate (the methyl ester of either glucuronate or 4-O-methyl-glucuronate) and either one of two acceptor molecules (benzyl alcohol or 3-phenyl-1-propanol) we demonstrate that the enzyme can perform transesterification and it serves as a method for assessing the enzyme's alcohol preferences. CONCLUSION CuGE preferentially forms the γ-ester from the methyl ester of 4-O-methyl-glucuronate and 3-phenyl-1-propanol and the enzyme's substrate preferences are primarily dictated by the presence of the 4-O-methylation on the glucuronoyl donor, and secondly on the type of alcohol.
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Affiliation(s)
- Valentina Perna
- Department of Biotechnology and Biomedicine, Technical University of Denmark, 2800, Kgs Lyngby, Denmark
| | - Jane Wittrup Agger
- Department of Biotechnology and Biomedicine, Technical University of Denmark, 2800, Kgs Lyngby, Denmark.
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Seveso A, Mazurkewich S, Banerjee S, Poulsen JCN, Lo Leggio L, Larsbrink J. Polysaccharide utilization loci from Bacteroidota encode CE15 enzymes with possible roles in cleaving pectin-lignin bonds. Appl Environ Microbiol 2024; 90:e0176823. [PMID: 38179933 PMCID: PMC10807430 DOI: 10.1128/aem.01768-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Accepted: 11/23/2023] [Indexed: 01/06/2024] Open
Abstract
Lignocellulose is a renewable but complex material exhibiting high recalcitrance to enzymatic hydrolysis, which is attributed, in part, to the presence of covalent linkages between lignin and polysaccharides in the plant cell wall. Glucuronoyl esterases from carbohydrate esterase family 15 (CE15) have been proposed as an aid in reducing this recalcitrance by cleaving ester bonds found between lignin and glucuronoxylan. In the Bacteroidota phylum, some species organize genes related to carbohydrate metabolism in polysaccharide utilization loci (PULs) which encode all necessary proteins to bind, deconstruct, and respond to a target glycan. Bioinformatic analyses identified CE15 members in some PULs that appear to not target the expected glucuronoxylan. Here, five CE15 members from such PULs were investigated with the aim of gaining insights on their biological roles. The selected targets were characterized using glucuronoyl esterase model substrates and with a new synthetic molecule mimicking a putative ester linkage between pectin and lignin. The CE15 enzyme from Phocaeicola vulgatus was structurally determined by X-ray crystallography both with and without carbohydrate ligands with galacturonate binding in a distinct conformation than that of glucuronate. We further explored whether these CE15 enzymes could act akin to pectin methylesterases on pectin-rich biomass but did not find evidence to support the proposed activity. Based on the evidence gathered, the CE15 enzymes in the PULs expected to degrade pectin could be involved in cleavage of uronic acid esters in rhamnogalacturonans.IMPORTANCEThe plant cell wall is a highly complex matrix, and while most of its polymers interact non-covalently, there are also covalent bonds between lignin and carbohydrates. Bonds between xylan and lignin are known, such as the glucuronoyl ester bonds that are cleavable by CE15 enzymes. Our work here indicates that enzymes from CE15 may also have other activities, as we have discovered enzymes in PULs proposed to target other polysaccharides, including pectin. Our study represents the first investigation of such enzymes. Our first hypothesis that the enzymes would act as pectin methylesterases was shown to be false, and we instead propose that they may cleave other esters on complex pectins such as rhamnogalacturonan II. The work presents both the characterization of five novel enzymes and can also provide indirect information about the components of the cell wall itself, which is a highly challenging material to chemically analyze in fine detail.
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Affiliation(s)
- Andrea Seveso
- Wallenberg Wood Science Center, Division of Industrial Biotechnology, Department of Life Sciences, Chalmers University of Technology, Gothenburg, Sweden
| | - Scott Mazurkewich
- Wallenberg Wood Science Center, Division of Industrial Biotechnology, Department of Life Sciences, Chalmers University of Technology, Gothenburg, Sweden
| | - Sanchari Banerjee
- Department of Chemistry, University of Copenhagen, Copenhagen, Denmark
| | | | - Leila Lo Leggio
- Department of Chemistry, University of Copenhagen, Copenhagen, Denmark
| | - Johan Larsbrink
- Wallenberg Wood Science Center, Division of Industrial Biotechnology, Department of Life Sciences, Chalmers University of Technology, Gothenburg, Sweden
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