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Fujita K, Tsunomachi H, Lixia P, Maruyama S, Miyake M, Dakeshita A, Kitahara K, Tanaka K, Ito Y, Ishiwata A, Fushinobu S. Bifidobacterial GH146 β-L-arabinofuranosidase for the removal of β1,3-L-arabinofuranosides on plant glycans. Appl Microbiol Biotechnol 2024; 108:199. [PMID: 38324037 PMCID: PMC10850190 DOI: 10.1007/s00253-024-13014-8] [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: 11/16/2023] [Revised: 12/29/2023] [Accepted: 01/14/2024] [Indexed: 02/08/2024]
Abstract
L-Arabinofuranosides with β-linkages are present in several plant molecules, such as arabinogalactan proteins (AGPs), extensin, arabinan, and rhamnogalacturonan-II. We previously characterized a β-L-arabinofuranosidase from Bifidobacterium longum subsp. longum JCM 1217, Bll1HypBA1, which was found to belong to the glycoside hydrolase (GH) family 127. This strain encodes two GH127 genes and two GH146 genes. In the present study, we characterized a GH146 β-L-arabinofuranosidase, Bll3HypBA1 (BLLJ_1848), which was found to constitute a gene cluster with AGP-degrading enzymes. This recombinant enzyme degraded AGPs and arabinan, which contain Araf-β1,3-Araf structures. In addition, the recombinant enzyme hydrolyzed oligosaccharides containing Araf-β1,3-Araf structures but not those containing Araf-β1,2-Araf and Araf-β1,5-Araf structures. The crystal structures of Bll3HypBA1 were determined at resolutions up to 1.7 Å. The monomeric structure of Bll3HypBA1 comprised a catalytic (α/α)6 barrel and two β-sandwich domains. A hairpin structure with two β-strands was observed in Bll3HypBA1, to extend from a β-sandwich domain and partially cover the active site. The active site contains a Zn2+ ion coordinated by Cys3-Glu and exhibits structural conservation of the GH127 cysteine glycosidase Bll1HypBA1. This is the first study to report on a β1,3-specific β-L-arabinofuranosidase. KEY POINTS: • β1,3-l-Arabinofuranose residues are present in arabinogalactan proteins and arabinans as a terminal sugar. • β-l-Arabinofuranosidases are widely present in intestinal bacteria. • Bll3HypBA1 is the first enzyme characterized as a β1,3-linkage-specific β-l-arabinofuranosidase.
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Affiliation(s)
- Kiyotaka Fujita
- Faculty of Agriculture, Kagoshima University, 1-21-24 Korimoto, Kagoshima, Kagoshima, 890-0065, Japan.
- The United Graduate School of Agricultural Sciences, Kagoshima University, 1-21-24 Korimoto, Kagoshima, Kagoshima, 890-0065, Japan.
| | - Hanako Tsunomachi
- Faculty of Agriculture, Kagoshima University, 1-21-24 Korimoto, Kagoshima, Kagoshima, 890-0065, Japan
| | - Pan Lixia
- Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-Ku, Tokyo, 113-8657, Japan
- National Key Laboratory of Non-food Biomass Energy Technology, Guangxi Key Laboratory of Marine Natural Products and Combinatorial Biosynthesis Chemistry, Guangxi Academy of Sciences, Nanning, 530007, China
| | - Shun Maruyama
- Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-Ku, Tokyo, 113-8657, Japan
| | - Masayuki Miyake
- Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-Ku, Tokyo, 113-8657, Japan
| | - Aimi Dakeshita
- Faculty of Agriculture, Kagoshima University, 1-21-24 Korimoto, Kagoshima, Kagoshima, 890-0065, Japan
| | - Kanefumi Kitahara
- Faculty of Agriculture, Kagoshima University, 1-21-24 Korimoto, Kagoshima, Kagoshima, 890-0065, Japan
- The United Graduate School of Agricultural Sciences, Kagoshima University, 1-21-24 Korimoto, Kagoshima, Kagoshima, 890-0065, Japan
| | - Katsunori Tanaka
- RIKEN, Cluster for Pioneering Research, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
- Department of Chemical Science and Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-Ku, Tokyo, 152-8552, Japan
| | - Yukishige Ito
- RIKEN, Cluster for Pioneering Research, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
- Graduate School of Science, Osaka University, 1-1 Machikaneyama-Cho, Toyonaka, Osaka, 560-0043, Japan
| | - Akihiro Ishiwata
- RIKEN, Cluster for Pioneering Research, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan
| | - Shinya Fushinobu
- Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-Ku, Tokyo, 113-8657, Japan.
- Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-Ku, Tokyo, 113-8657, Japan.
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Zhu XY, Li Y, Xue CX, Lidbury IDEA, Todd JD, Lea-Smith DJ, Tian J, Zhang XH, Liu J. Deep-sea Bacteroidetes from the Mariana Trench specialize in hemicellulose and pectin degradation typically associated with terrestrial systems. MICROBIOME 2023; 11:175. [PMID: 37550707 PMCID: PMC10405439 DOI: 10.1186/s40168-023-01618-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 07/11/2023] [Indexed: 08/09/2023]
Abstract
BACKGROUND Hadal trenches (>6000 m) are the deepest oceanic regions on Earth and depocenters for organic materials. However, how these enigmatic microbial ecosystems are fueled is largely unknown, particularly the proportional importance of complex polysaccharides introduced through deposition from the photic surface waters above. In surface waters, Bacteroidetes are keystone taxa for the cycling of various algal-derived polysaccharides and the flux of carbon through the photic zone. However, their role in the hadal microbial loop is almost unknown. RESULTS Here, culture-dependent and culture-independent methods were used to study the potential of Bacteroidetes to catabolize diverse polysaccharides in Mariana Trench waters. Compared to surface waters, the bathypelagic (1000-4000 m) and hadal (6000-10,500 m) waters harbored distinct Bacteroidetes communities, with Mesoflavibacter being enriched at ≥ 4000 m and Bacteroides and Provotella being enriched at 10,400-10,500 m. Moreover, these deep-sea communities possessed distinct gene pools encoding for carbohydrate active enzymes (CAZymes), suggesting different polysaccharide sources are utilised in these two zones. Compared to surface counterparts, deep-sea Bacteroidetes showed significant enrichment of CAZyme genes frequently organized into polysaccharide utilization loci (PULs) targeting algal/plant cell wall polysaccharides (i.e., hemicellulose and pectin), that were previously considered an ecological trait associated with terrestrial Bacteroidetes only. Using a hadal Mesoflavibacter isolate (MTRN7), functional validation of this unique genetic potential was demonstrated. MTRN7 could utilize pectic arabinans, typically associated with land plants and phototrophic algae, as the carbon source under simulated deep-sea conditions. Interestingly, a PUL we demonstrate is likely horizontally acquired from coastal/land Bacteroidetes was activated during growth on arabinan and experimentally shown to encode enzymes that hydrolyze arabinan at depth. CONCLUSIONS Our study implies that hadal Bacteroidetes exploit polysaccharides poorly utilized by surface populations via an expanded CAZyme gene pool. We propose that sinking cell wall debris produced in the photic zone can serve as an important carbon source for hadal heterotrophs and play a role in shaping their communities and metabolism. Video Abstract.
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Affiliation(s)
- Xiao-Yu Zhu
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, College of Marine Life Sciences, Ocean University of China, 5 Yushan Road, Qingdao, 266003, China
- Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao, 266273, China
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003, China
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
| | - Yang Li
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, College of Marine Life Sciences, Ocean University of China, 5 Yushan Road, Qingdao, 266003, China
- Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao, 266273, China
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003, China
| | - Chun-Xu Xue
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, College of Marine Life Sciences, Ocean University of China, 5 Yushan Road, Qingdao, 266003, China
- Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao, 266273, China
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003, China
| | - Ian D E A Lidbury
- Molecular Microbiology: Biochemistry to Disease, School of Biosciences, The University of Sheffield, Sheffield, S10 2TN, UK
| | - Jonathan D Todd
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
| | - David J Lea-Smith
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
| | - Jiwei Tian
- Key Laboratory of Physical Oceanography, Ministry of Education, Ocean University of China, Qingdao, 266100, China
| | - Xiao-Hua Zhang
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, College of Marine Life Sciences, Ocean University of China, 5 Yushan Road, Qingdao, 266003, China
- Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao, 266273, China
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003, China
| | - Jiwen Liu
- Frontiers Science Center for Deep Ocean Multispheres and Earth System, College of Marine Life Sciences, Ocean University of China, 5 Yushan Road, Qingdao, 266003, China.
- Laboratory for Marine Ecology and Environmental Science, Laoshan Laboratory, Qingdao, 266273, China.
- Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003, China.
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Dionisi HM, Lozada M, Campos E. Diversity of GH51 α-L-arabinofuranosidase homolog sequences from subantarctic intertidal sediments. Biologia (Bratisl) 2023. [DOI: 10.1007/s11756-023-01382-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023]
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Liu Y, Angelov A, Feiler W, Baudrexl M, Zverlov V, Liebl W, Vanderhaeghen S. Arabinan saccharification by biogas reactor metagenome-derived arabinosyl hydrolases. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2022; 15:121. [PMID: 36371193 PMCID: PMC9655821 DOI: 10.1186/s13068-022-02216-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Accepted: 10/19/2022] [Indexed: 06/16/2023]
Abstract
BACKGROUND Plant cell walls represent the most plentiful renewable organic resource on earth, but due to their heterogeneity, complex structure and partial recalcitrance, their use as biotechnological feedstock is still limited. RESULTS In order to identify efficient enzymes for polysaccharide breakdown, we have carried out functional screening of metagenomic fosmid libraries from biogas fermenter microbial communities grown on sugar beet pulp, an arabinan-rich agricultural residue, or other sources containing microbes that efficiently depolymerize polysaccharides, using CPH (chromogenic polysaccharide hydrogel) or ICB (insoluble chromogenic biomass) labeled polysaccharide substrates. Seventy-one depolymerase-encoding genes were identified from 55 active fosmid clones by using Illumina and Sanger sequencing and dbCAN CAZyme (carbohydrate-active enzyme) annotation. An around 56 kb assembled DNA fragment putatively originating from Xylanivirga thermophila strain or a close relative was analyzed in detail. It contained 48 ORFs (open reading frames), of which 31 were assigned to sugar metabolism. Interestingly, a large number of genes for enzymes putatively involved in degradation and utilization of arabinose-containing carbohydrates were found. Seven putative arabinosyl hydrolases from this DNA fragment belonging to glycoside hydrolase (GH) families GH51 and GH43 were biochemically characterized, revealing two with endo-arabinanase activity and four with exo-α-L-arabinofuranosidase activity but with complementary cleavage properties. These enzymes were found to act synergistically and can completely hydrolyze SBA (sugar beet arabinan) and DA (debranched arabinan). CONCLUSIONS We screened 32,776 fosmid clones from several metagenomic libraries with chromogenic lignocellulosic substrates for functional enzymes to advance the understanding about the saccharification of recalcitrant lignocellulose. Seven putative X. thermophila arabinosyl hydrolases were characterized for pectic substrate degradation. The arabinosyl hydrolases displayed maximum activity and significant long-term stability around 50 °C. The enzyme cocktails composed in this study fully degraded the arabinan substrates and thus could serve for arabinose production in food and biofuel industries.
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Affiliation(s)
- Yajing Liu
- Chair of Microbiology, Technical University of Munich, Emil-Ramann-Straβe 4, 85354 Freising-Weihenstephan, Germany
- Present Address: Chair of Chemistry of Biogenic Resources, Technical University of Munich, Schulgasse 16, 94315 Straubing, Germany
| | - Angel Angelov
- Chair of Microbiology, Technical University of Munich, Emil-Ramann-Straβe 4, 85354 Freising-Weihenstephan, Germany
- Present Address: NGS Competence Center Tübingen, Universitätsklinikum Tübingen, Calwerstraße 7, 72076 Tübingen, Germany
| | - Werner Feiler
- Chair of Microbiology, Technical University of Munich, Emil-Ramann-Straβe 4, 85354 Freising-Weihenstephan, Germany
| | - Melanie Baudrexl
- Chair of Microbiology, Technical University of Munich, Emil-Ramann-Straβe 4, 85354 Freising-Weihenstephan, Germany
| | - Vladimir Zverlov
- Chair of Microbiology, Technical University of Munich, Emil-Ramann-Straβe 4, 85354 Freising-Weihenstephan, Germany
| | - Wolfgang Liebl
- Chair of Microbiology, Technical University of Munich, Emil-Ramann-Straβe 4, 85354 Freising-Weihenstephan, Germany
| | - Sonja Vanderhaeghen
- Chair of Microbiology, Technical University of Munich, Emil-Ramann-Straβe 4, 85354 Freising-Weihenstephan, Germany
- Present Address: IMGM Laboratories, Lochhamer Straße 29a, 82152 Planegg, Germany
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Yun EJ, Yu S, Kim YA, Liu JJ, Kang NJ, Jin YS, Kim KH. In Vitro Prebiotic and Anti-Colon Cancer Activities of Agar-Derived Sugars from Red Seaweeds. Mar Drugs 2021; 19:md19040213. [PMID: 33921308 PMCID: PMC8070132 DOI: 10.3390/md19040213] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2021] [Revised: 04/04/2021] [Accepted: 04/07/2021] [Indexed: 01/09/2023] Open
Abstract
Numerous health benefits of diets containing red seaweeds or agar-derived sugar mixtures produced by enzymatic or acid hydrolysis of agar have been reported. However, among various agar-derived sugars, the key components that confer health-beneficial effects, such as prebiotic and anti-colon cancer activities, remain unclear. Here, we prepared various agar-derived sugars by multiple enzymatic reactions using an endo-type and an exo-type of β-agarase and a neoagarobiose hydrolase and tested their in vitro prebiotic and anti-colon cancer activities. Among various agar-derived sugars, agarotriose exhibited prebiotic activity that was verified based on the fermentability of agarotriose by probiotic bifidobacteria. Furthermore, we demonstrated the anti-colon cancer activity of 3,6-anhydro-l-galactose, which significantly inhibited the proliferation of human colon cancer cells and induced their apoptosis. Our results provide crucial information regarding the key compounds derived from red seaweeds that confer beneficial health effects, including prebiotic and anti-colon cancer activities, to the host.
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Affiliation(s)
- Eun Ju Yun
- Department of Biotechnology, Graduate School, Korea University, Seoul 02841, Korea; (E.J.Y.); (S.Y.)
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA;
| | - Sora Yu
- Department of Biotechnology, Graduate School, Korea University, Seoul 02841, Korea; (E.J.Y.); (S.Y.)
| | - Young-Ah Kim
- School of Food Science and Biotechnology, Kyungpook National University, Daegu 41566, Korea; (Y.-A.K.); (N.J.K.)
| | - Jing-Jing Liu
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA;
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Nam Joo Kang
- School of Food Science and Biotechnology, Kyungpook National University, Daegu 41566, Korea; (Y.-A.K.); (N.J.K.)
| | - Yong-Su Jin
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA;
- Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Correspondence: (Y.-S.J.); (K.H.K.)
| | - Kyoung Heon Kim
- Department of Biotechnology, Graduate School, Korea University, Seoul 02841, Korea; (E.J.Y.); (S.Y.)
- Correspondence: (Y.-S.J.); (K.H.K.)
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Cann I, Pereira GV, Abdel-Hamid AM, Kim H, Wefers D, Kayang BB, Kanai T, Sato T, Bernardi RC, Atomi H, Mackie RI. Thermophilic Degradation of Hemicellulose, a Critical Feedstock in the Production of Bioenergy and Other Value-Added Products. Appl Environ Microbiol 2020; 86:e02296-19. [PMID: 31980431 PMCID: PMC7082577 DOI: 10.1128/aem.02296-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Renewable fuels have gained importance as the world moves toward diversifying its energy portfolio. A critical step in the biomass-to-bioenergy initiative is deconstruction of plant cell wall polysaccharides to their unit sugars for subsequent fermentation to fuels. To acquire carbon and energy for their metabolic processes, diverse microorganisms have evolved genes encoding enzymes that depolymerize polysaccharides to their carbon/energy-rich building blocks. The microbial enzymes mostly target the energy present in cellulose, hemicellulose, and pectin, three major forms of energy storage in plants. In the effort to develop bioenergy as an alternative to fossil fuel, a common strategy is to harness microbial enzymes to hydrolyze cellulose to glucose for fermentation to fuels. However, the conversion of plant biomass to renewable fuels will require both cellulose and hemicellulose, the two largest components of the plant cell wall, as feedstock to improve economic feasibility. Here, we explore the enzymes and strategies evolved by two well-studied bacteria to depolymerize the hemicelluloses xylan/arabinoxylan and mannan. The sets of enzymes, in addition to their applications in biofuels and value-added chemical production, have utility in animal feed enzymes, a rapidly developing industry with potential to minimize adverse impacts of animal agriculture on the environment.
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Affiliation(s)
- Isaac Cann
- Department of Animal Science, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Energy Biosciences Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Microbiome Metabolic Engineering Theme, Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Kyoto, Japan
| | - Gabriel V Pereira
- Department of Animal Science, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Energy Biosciences Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Microbiome Metabolic Engineering Theme, Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Ahmed M Abdel-Hamid
- Energy Biosciences Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Microbiome Metabolic Engineering Theme, Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Heejin Kim
- Microbiome Metabolic Engineering Theme, Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Daniel Wefers
- Karlsruhe Institute of Technology, Institute of Applied Biosciences, Department of Food Chemistry and Phytochemistry, Karlsruhe, Germany
| | - Boniface B Kayang
- Department of Animal Science, School of Agriculture, University of Ghana, Legon, Ghana
| | - Tamotsu Kanai
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Kyoto, Japan
| | - Takaaki Sato
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Kyoto, Japan
- JST, CREST, Tokyo, Japan
| | - Rafael C Bernardi
- NIH Center for Macromolecular Modeling and Bioinformatics, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Haruyuki Atomi
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Kyoto, Japan
- JST, CREST, Tokyo, Japan
| | - Roderick I Mackie
- Department of Animal Science, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Division of Nutritional Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Energy Biosciences Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Microbiome Metabolic Engineering Theme, Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
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Bertucci M, Calusinska M, Goux X, Rouland-Lefèvre C, Untereiner B, Ferrer P, Gerin PA, Delfosse P. Carbohydrate Hydrolytic Potential and Redundancy of an Anaerobic Digestion Microbiome Exposed to Acidosis, as Uncovered by Metagenomics. Appl Environ Microbiol 2019; 85:e00895-19. [PMID: 31152018 PMCID: PMC6643232 DOI: 10.1128/aem.00895-19] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 05/26/2019] [Indexed: 12/22/2022] Open
Abstract
Increased hydrolysis of easily digestible biomass may lead to acidosis of anaerobic reactors and decreased methane production. Previously, it was shown that the structure of microbial communities changed during acidosis; however, once the conditions are back to optimal, biogas (initially CO2) production quickly restarts. This suggests the retention of the community functional redundancy during the process failure. In this study, with the use of metagenomics and downstream bioinformatics analyses, we characterize the carbohydrate hydrolytic potential of the microbial community, with a special focus on acidosis. To that purpose, carbohydrate-active enzymes were identified, and to further link the community hydrolytic potential with key microbes, bacterial genomes were reconstructed. In addition, we characterized biochemically the specificity and activity of selected enzymes, thus verifying the accuracy of the in silico predictions. The results confirm the retention of the community hydrolytic potential during acidosis and indicate Bacteroidetes to be largely involved in biomass degradation. Bacteroidetes showed higher diversity and genomic content of carbohydrate hydrolytic enzymes that might favor the dominance of this phylum over other bacteria in some anaerobic reactors. The combination of bioinformatic analyses and activity tests enabled us to propose a model of acetylated glucomannan degradation by BacteroidetesIMPORTANCE The enzymatic hydrolysis of lignocellulosic biomass is mainly driven by the action of carbohydrate-active enzymes. By characterizing the gene profiles at the different stages of the anaerobic digestion experiment, we showed that the microbiome retains its hydrolytic functional redundancy even during severe acidosis, despite significant changes in taxonomic composition. By analyzing reconstructed bacterial genomes, we demonstrate that Bacteroidetes hydrolytic gene diversity likely favors the abundance of this phylum in some anaerobic digestion systems. Further, we observe genetic redundancy within the Bacteroidetes group, which accounts for the preserved hydrolytic potential during acidosis. This work also uncovers new polysaccharide utilization loci involved in the deconstruction of various biomasses and proposes the model of acetylated glucomannan degradation by Bacteroidetes Acetylated glucomannan-enriched biomass is a common substrate for many industries, including pulp and paper production. Using naturally evolved cocktails of enzymes for biomass pretreatment could be an interesting alternative to the commonly used chemical pretreatments.
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Affiliation(s)
- Marie Bertucci
- Environmental Research and Innovation Department, Luxembourg Institute of Science and Technology, Belvaux, Luxembourg
- Laboratory of Bioengineering, Earth and Life Institute, Applied Microbiology, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Magdalena Calusinska
- Environmental Research and Innovation Department, Luxembourg Institute of Science and Technology, Belvaux, Luxembourg
| | - Xavier Goux
- Environmental Research and Innovation Department, Luxembourg Institute of Science and Technology, Belvaux, Luxembourg
| | - Corinne Rouland-Lefèvre
- Institute of Ecology and Environmental Sciences, Research Institute Development, Sorbonne Universités, Bondy, France
| | - Boris Untereiner
- Environmental Research and Innovation Department, Luxembourg Institute of Science and Technology, Belvaux, Luxembourg
| | - Pau Ferrer
- Environmental Research and Innovation Department, Luxembourg Institute of Science and Technology, Belvaux, Luxembourg
| | - Patrick A Gerin
- Laboratory of Bioengineering, Earth and Life Institute, Applied Microbiology, Université Catholique de Louvain, Louvain-la-Neuve, Belgium
| | - Philippe Delfosse
- Environmental Research and Innovation Department, Luxembourg Institute of Science and Technology, Belvaux, Luxembourg
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