1
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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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2
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Li DD, Zhang Z, Wang JN, Zhang P, Liu Y, Li YZ. Estimate of the degradation potentials of cellulose, xylan, and chitin across global prokaryotic communities. Environ Microbiol 2023; 25:397-409. [PMID: 36446618 DOI: 10.1111/1462-2920.16290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Accepted: 11/26/2022] [Indexed: 12/03/2022]
Abstract
Complex polysaccharides (e.g. cellulose, xylan, and chitin), the most abundant renewable biomass resources available on Earth, are mainly degraded by microorganisms in nature. However, little is known about the global distribution of the enzymes and microorganisms responsible for the degradation of cellulose, xylan, and chitin in natural environments. Through large-scale alignments between the sequences released by the Earth Microbiome Project and sequenced prokaryotic genomes, we determined that almost all prokaryotic communities have the functional potentials to degrade cellulose, xylan, and chitin. The median abundances of genes encoding putative cellulases, xylanases, and chitinases in global prokaryotic communities are 0.51 (0.17-1.01), 0.24 (0.05-0.57), and 0.33 (0.11-0.71) genes/cell, respectively, and the composition and abundance of these enzyme systems are environmentally varied. The taxonomic sources of the three enzymes are highly diverse within prokaryotic communities, and the main factor influencing the diversity is the community's alpha diversity index rather than gene abundance. Moreover, there are obvious differences in taxonomic sources among different communities, and most genera with degradation potentials are narrowly distributed. In conclusion, our analysis preliminarily depicts a panorama of cellulose-, xylan-, and chitin-degrading enzymatic systems across global prokaryotic communities.
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Affiliation(s)
- Dan-Dan Li
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
| | - Zheng Zhang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
- Suzhou Research Institute, Shandong University, Suzhou, China
| | - Jia-Ning Wang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
| | - Peng Zhang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
| | - Ya Liu
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
| | - Yue-Zhong Li
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao, China
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3
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Sung JY, Lee YJ, Cho YJ, Shin MN, Lee SJ, Lee HS, Koh H, Bae JW, Shin JH, Kim HJ, Lee DW. A large-scale metagenomic study for enzyme profiles using the focused identification of the NGS-based definitive enzyme research (FINDER) strategy. Biotechnol Bioeng 2021; 118:4360-4374. [PMID: 34309016 DOI: 10.1002/bit.27904] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Revised: 04/23/2021] [Accepted: 07/23/2021] [Indexed: 11/09/2022]
Abstract
Excavating the molecular details of many diverse enzymes from metagenomes remains challenging in agriculture, food, health, and environmental fields. We present a versatile method that accelerates metabolic enzyme discovery for highly selective gene capture in metagenomes using next-generation sequencing. Culture-independent enzyme mining of environmental DNA is based on a set of short identifying degenerate sequences specific for a wide range of enzyme superfamilies, followed by multiplexed DNA barcode sequencing. A strategy of 'focused identification of next-generation sequencing-based definitive enzyme research' enabled us to generate targeted enzyme datasets from metagenomes, resulting in minimal hands-on obtention of high-throughput biological diversity and potential function profiles, without being time-consuming. This method also provided a targeted inventory of predicted proteins and molecular features of metabolic activities from several metagenomic samples. We suggest that the efficiency and sensitivity of this method will accelerate the decryption of microbial diversity and the signature of proteins and their metabolism from environmental samples.
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Affiliation(s)
- Jae-Yoon Sung
- Department of Biotechnology, Yonsei University, Seoul, South Korea
| | - Yong-Jik Lee
- Department of Bio-Cosmetics, Seowon University, Chung-Ju, South Korea
| | - Yong-Joon Cho
- Department of Biological Sciences and Research Institute of Basic Sciences, Seoul National University, Seoul, South Korea
| | - Myeong-Na Shin
- Department of Central Area Crop Science, NICS, RDA, Suwon, South Korea
| | - Sang-Jae Lee
- Major in Food Biotechnology, Silla University, Busan, South Korea
| | - Han-Seung Lee
- Major in Food Biotechnology, Silla University, Busan, South Korea
| | - Hong Koh
- Department of Pediatrics, Yonsei University, Seoul, South Korea
| | - Jin-Woo Bae
- Department of Biology, Kyung Hee University, Seoul, South Korea
| | - Jae-Ho Shin
- Department of Applied Biosciences, Kyungpook National University, Daegu, South Korea
| | - Hyun Jung Kim
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, Texas, USA
| | - Dong-Woo Lee
- Department of Biotechnology, Yonsei University, Seoul, South Korea
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4
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Karnaouri A, Zerva A, Christakopoulos P, Topakas E. Screening of Recombinant Lignocellulolytic Enzymes Through Rapid Plate Assays. Methods Mol Biol 2021; 2178:479-503. [PMID: 33128767 DOI: 10.1007/978-1-0716-0775-6_30] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In the search for novel biomass-degrading enzymes through mining microbial genomes, it is necessary to apply functional tests during high-throughput screenings, which are capable of detecting enzymatic activities directly by way of plate assay. Using the most efficient expression systems of Escherichia coli and Pichia pastoris, the production of a high amount of His-tagged recombinant proteins could be thrived, allowing the one-step isolation by affinity chromatography. Here, we describe simple and efficient assay techniques for the detection of various biomass-degrading enzymatic activities on agar plates, such as cellulolytic, hemicellulolytic, and ligninolytic activities and their isolation using immobilized-metal affinity chromatography.
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Affiliation(s)
- Anthi Karnaouri
- Industrial Biotechnology and Biocatalysis Group, Biotechnology Laboratory, Department of Synthesis and Development of Industrial Processes, School of Chemical Engineering, National Technical University of Athens, Athens, Greece
| | - Anastasia Zerva
- Industrial Biotechnology and Biocatalysis Group, Biotechnology Laboratory, Department of Synthesis and Development of Industrial Processes, School of Chemical Engineering, National Technical University of Athens, Athens, Greece
| | - Paul Christakopoulos
- Biochemical Process Engineering, Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden
| | - Evangelos Topakas
- Industrial Biotechnology and Biocatalysis Group, Biotechnology Laboratory, Department of Synthesis and Development of Industrial Processes, School of Chemical Engineering, National Technical University of Athens, Athens, Greece.
- Biochemical Process Engineering, Chemical Engineering, Department of Civil, Environmental and Natural Resources Engineering, Luleå University of Technology, Luleå, Sweden.
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5
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López-Mondéjar R, Algora C, Baldrian P. Lignocellulolytic systems of soil bacteria: A vast and diverse toolbox for biotechnological conversion processes. Biotechnol Adv 2019; 37:107374. [DOI: 10.1016/j.biotechadv.2019.03.013] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 03/06/2019] [Accepted: 03/21/2019] [Indexed: 12/12/2022]
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6
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Wierzbicka-Woś A, Henneberger R, Batista-García RA, Martínez-Ávila L, Jackson SA, Kennedy J, Dobson ADW. Biochemical Characterization of a Novel Monospecific Endo-β-1,4-Glucanase Belonging to GH Family 5 From a Rhizosphere Metagenomic Library. Front Microbiol 2019; 10:1342. [PMID: 31258522 PMCID: PMC6587912 DOI: 10.3389/fmicb.2019.01342] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 05/29/2019] [Indexed: 11/16/2022] Open
Abstract
Cellulases have a broad range of different industrial applications, ranging from food and beverages to pulp and paper and the biofuels area. Here a metagenomics based strategy was used to identify the cellulolytic enzyme CelRH5 from the rhizosphere. CelRH5 is a novel monospecific endo-β-1,4-glucanase belonging to the glycosyl hydrolase family 5 (GH5). Structural based modeling analysis indicated that CelRH5 is related to endo-β-1,4-glucanases derived from thermophilic microorganisms such as Thermotoga maritima, Fervidobacterium nodosum, and Ruminiclostridium thermocellum sharing 30-40% amino acid sequence identity. The molecular weight of the enzyme was determined as 40.5 kDa. Biochemical analyses revealed that the enzyme displayed good activity with soluble forms of cellulose as a substrate such as ostazin brilliant red hydroxyethyl cellulose (OBR-HEC), carboxymethylcellulose (CMC), hydroxyethyl cellulose (HEC), and insoluble azurine cross-linked hydroxyethylcellulose (AZCL-HEC). The enzyme shows highest enzymatic activity at pH 6.5 with high pH tolerance, remaining stable in the pH range 4.5–8.5. Highest activity was observed at 40°C, but CelRH5 is psychrotolerant being active and stable at temperatures below 30°C. The presence of the final products of cellulose hydrolysis (glucose and cellobiose) or metal ions such as Na+, K+, Li+, and Mg2+, as well as ethylenediaminetetraacetic acid (EDTA), urea, dithiothreitol (DTT), dimethyl sulfoxide (DMSO), 2-mercaptoethanol (2-ME) or glycerol, did not have a marked effect on CelRH5 activity. However, the enzyme is quite sensitive to the presence of 10 mM ions Zn2+, Ni2+, Co2+, Fe3+ and reagents such as 1 M guanidine HCl, 0.1% sodium dodecyl sulfate (SDS) and 20% ethanol. Given that it is psychrotolerant and retains activity in the presence of final cellulose degradation products, metal ions and various reagents, which are common in many technological processes; CelRH5 may be potential suitability for a variety of different biotechnological applications.
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Affiliation(s)
- Anna Wierzbicka-Woś
- Environmental Research Institute, University College Cork, Cork, Ireland.,Department of Microbiology, Faculty of Biology, University of Szczecin, Szczecin, Poland
| | - Ruth Henneberger
- Environmental Research Institute, University College Cork, Cork, Ireland.,Institute for Molecular Health Sciences, ETH Zürich, Zurich, Switzerland
| | - Ramón Alberto Batista-García
- Centro de Investigación en Dinámica Celular, Instituto de Investigación en Ciencias Básicas y Aplicadas, Universidad Autónoma del Estado de Morelos, Cuernavaca, Mexico
| | - Liliana Martínez-Ávila
- Centro de Investigación en Dinámica Celular, Instituto de Investigación en Ciencias Básicas y Aplicadas, Universidad Autónoma del Estado de Morelos, Cuernavaca, Mexico
| | - Stephen A Jackson
- Environmental Research Institute, University College Cork, Cork, Ireland.,School of Microbiology, University College Cork, Cork, Ireland
| | | | - Alan D W Dobson
- Environmental Research Institute, University College Cork, Cork, Ireland.,School of Microbiology, University College Cork, Cork, Ireland
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7
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High-Throughput Recovery and Characterization of Metagenome-Derived Glycoside Hydrolase-Containing Clones as a Resource for Biocatalyst Development. mSystems 2019; 4:4/4/e00082-19. [PMID: 31164449 PMCID: PMC6550366 DOI: 10.1128/msystems.00082-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The generation of new biocatalysts for plant biomass degradation and glycan synthesis has typically relied on the characterization and investigation of one or a few enzymes at a time. By coupling functional metagenomic screening and high-throughput functional characterization, we can progress beyond the current scale of catalyst discovery and provide rapid annotation of catalyst function. By functionally screening environmental DNA from many diverse sources, we have generated a suite of active glycoside hydrolase-containing clones and demonstrated their reaction parameters. We then demonstrated the utility of this collection through the generation of a new catalyst for the formation of azido-modified glycans. Further interrogation of this collection of clones will expand our biocatalytic toolbox, with potential application to biomass deconstruction and synthesis of glycans. Functional metagenomics is a powerful tool for both the discovery and development of biocatalysts. This study presents the high-throughput functional screening of 22 large-insert fosmid libraries containing over 300,000 clones sourced from natural and engineered ecosystems, characterization of active clones, and a demonstration of the utility of recovered genes or gene cassettes in the development of novel biocatalysts. Screening was performed in a 384-well-plate format with the fluorogenic substrate 4-methylumbelliferyl cellobioside, which releases a fluorescent molecule when cleaved by β-glucosidases or cellulases. The resulting set of 164 active clones was subsequently interrogated for substrate preference, reaction mechanism, thermal stability, and optimal pH. The environmental DNA harbored within each active clone was sequenced, and functional annotation revealed a cornucopia of carbohydrate-degrading enzymes. Evaluation of genomic-context information revealed both synteny and polymer-targeting loci within a number of sequenced clones. The utility of these fosmids was then demonstrated by identifying clones encoding activity on an unnatural glycoside (4-methylumbelliferyl 6-azido-6-deoxy-β-d-galactoside) and transforming one of the identified enzymes into a glycosynthase capable of forming taggable disaccharides. IMPORTANCE The generation of new biocatalysts for plant biomass degradation and glycan synthesis has typically relied on the characterization and investigation of one or a few enzymes at a time. By coupling functional metagenomic screening and high-throughput functional characterization, we can progress beyond the current scale of catalyst discovery and provide rapid annotation of catalyst function. By functionally screening environmental DNA from many diverse sources, we have generated a suite of active glycoside hydrolase-containing clones and demonstrated their reaction parameters. We then demonstrated the utility of this collection through the generation of a new catalyst for the formation of azido-modified glycans. Further interrogation of this collection of clones will expand our biocatalytic toolbox, with potential application to biomass deconstruction and synthesis of glycans.
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8
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Characterization of a thermoactive endoglucanase isolated from a biogas plant metagenome. Extremophiles 2019; 23:479-486. [PMID: 31119430 DOI: 10.1007/s00792-019-01099-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 05/02/2019] [Indexed: 12/30/2022]
Abstract
A metagenomic library from DNA isolated from a biogas plant was constructed and screened for thermoactive endoglucanases to gain insight into the enzymatic diversity involved in plant biomass breakdown at elevated temperatures. Two cellulase-encoding genes were identified and the corresponding proteins showed sequence similarities of 59% for Cel5A to a putative cellulase from Anaerolinea thermolimosa and 99% for Cel5B to a characterized endoglucanase isolated from a biogas plant reactor. The cellulase Cel5A consists of one catalytical domain showing sequence similarities to glycoside hydrolase family 5 and comprises 358 amino acids with a predicted molecular mass of 41.2 kDa. The gene coding for cel5A was successfully cloned and expressed in Escherichia coli C43(DE3). The recombinant protein was purified to homogeneity using affinity chromatography with a specific activity of 182 U/mg, and a yield of 74%. Enzymatic activity was detectable towards cellulose and mannan containing substrates and over a broad temperature range from 40 °C to 70 °C and a pH range from 4.0 to 7.0 with maximal activity at 55 °C and pH 5.0. Cel5A showed high thermostability at 60 °C without loss of activity after 24 h. Due to the enzymatic characteristics, Cel5A is an attractive candidate for the degradation of lignocellulosic material.
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9
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Enhancement the Cellulase Activity Induced by Endophytic Bacteria Using Calcium Nanoparticles. Curr Microbiol 2019; 76:346-354. [DOI: 10.1007/s00284-018-1614-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 12/13/2018] [Indexed: 10/27/2022]
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10
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Lepcha K, Ghosh S. Glycoside hydrolases from a thermophilic microbial consortium and their implication in the saccharification of agroresidues. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2018. [DOI: 10.1016/j.bcab.2018.05.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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11
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Schückel J, Kračun SK. Two-Dimensional High-Throughput Endo-Enzyme Screening Assays Based on Chromogenic Polysaccharide Hydrogel and Complex Biomass Substrates. Methods Mol Biol 2018; 1796:201-217. [PMID: 29856056 DOI: 10.1007/978-1-4939-7877-9_15] [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] [Indexed: 06/08/2023]
Abstract
In this chapter, we present a two-dimensional approach for high-throughput screening of endo-cellulases as well as other endo-acting enzymes. The method is based on chromogenic substrates, produced either from purified or complex material, providing valuable information about enzyme activity toward its target as well as that same target in a context of complex natural material normally encountered in bioindustrial settings. The enzymes that can be tested using this assay can be from virtually any source: in purified form, directly from microbial cultures or even from raw materials, enabling study of the interplay between enzyme mixtures such as synergistic or inhibitory effects. By using the method of analysis described in this chapter, enzymes can be screened and evaluated quickly and information pertinent to both the inherent properties of the enzyme itself as well as predictions about its performance on complex biomass samples can be obtained.
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12
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Bozan M, Akyol Ç, Ince O, Aydin S, Ince B. Application of next-generation sequencing methods for microbial monitoring of anaerobic digestion of lignocellulosic biomass. Appl Microbiol Biotechnol 2017; 101:6849-6864. [PMID: 28779289 DOI: 10.1007/s00253-017-8438-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 07/14/2017] [Accepted: 07/17/2017] [Indexed: 10/19/2022]
Abstract
The anaerobic digestion of lignocellulosic wastes is considered an efficient method for managing the world's energy shortages and resolving contemporary environmental problems. However, the recalcitrance of lignocellulosic biomass represents a barrier to maximizing biogas production. The purpose of this review is to examine the extent to which sequencing methods can be employed to monitor such biofuel conversion processes. From a microbial perspective, we present a detailed insight into anaerobic digesters that utilize lignocellulosic biomass and discuss some benefits and disadvantages associated with the microbial sequencing techniques that are typically applied. We further evaluate the extent to which a hybrid approach incorporating a variation of existing methods can be utilized to develop a more in-depth understanding of microbial communities. It is hoped that this deeper knowledge will enhance the reliability and extent of research findings with the end objective of improving the stability of anaerobic digesters that manage lignocellulosic biomass.
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Affiliation(s)
- Mahir Bozan
- Institute of Environmental Sciences, Boğaziçi University, Bebek, 34342, Istanbul, Turkey
| | - Çağrı Akyol
- Institute of Environmental Sciences, Boğaziçi University, Bebek, 34342, Istanbul, Turkey
| | - Orhan Ince
- Department of Environmental Engineering, Istanbul Technical University, Maslak, 34469, Istanbul, Turkey
| | - Sevcan Aydin
- Department of Genetics and Bioengineering, Nişantaşı University, Maslak, 34469, Istanbul, Turkey.
| | - Bahar Ince
- Institute of Environmental Sciences, Boğaziçi University, Bebek, 34342, Istanbul, Turkey
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13
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Badino SF, Christensen SJ, Kari J, Windahl MS, Hvidt S, Borch K, Westh P. Exo-exo synergy between Cel6A and Cel7A fromHypocrea jecorina: Role of carbohydrate binding module and the endo-lytic character of the enzymes. Biotechnol Bioeng 2017; 114:1639-1647. [DOI: 10.1002/bit.26276] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 02/17/2017] [Accepted: 02/21/2017] [Indexed: 01/08/2023]
Affiliation(s)
- Silke F. Badino
- Research Unit for Functional Biomaterials; Department of Science and Environment; INM; Roskilde University; 1 Universitetsvej, Build. 28C, DK-4000 Roskilde Denmark
| | - Stefan J. Christensen
- Research Unit for Functional Biomaterials; Department of Science and Environment; INM; Roskilde University; 1 Universitetsvej, Build. 28C, DK-4000 Roskilde Denmark
| | - Jeppe Kari
- Research Unit for Functional Biomaterials; Department of Science and Environment; INM; Roskilde University; 1 Universitetsvej, Build. 28C, DK-4000 Roskilde Denmark
| | - Michael S. Windahl
- Research Unit for Functional Biomaterials; Department of Science and Environment; INM; Roskilde University; 1 Universitetsvej, Build. 28C, DK-4000 Roskilde Denmark
- Novozymes A/S; Bagsvaerd Denmark
| | - Søren Hvidt
- Research Unit for Functional Biomaterials; Department of Science and Environment; INM; Roskilde University; 1 Universitetsvej, Build. 28C, DK-4000 Roskilde Denmark
| | | | - Peter Westh
- Research Unit for Functional Biomaterials; Department of Science and Environment; INM; Roskilde University; 1 Universitetsvej, Build. 28C, DK-4000 Roskilde Denmark
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14
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Müller CA, Obermeier MM, Berg G. Bioprospecting plant-associated microbiomes. J Biotechnol 2016; 235:171-80. [DOI: 10.1016/j.jbiotec.2016.03.033] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 03/17/2016] [Accepted: 03/21/2016] [Indexed: 10/22/2022]
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15
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Rashamuse K, Sanyika Tendai W, Mathiba K, Ngcobo T, Mtimka S, Brady D. Metagenomic mining of glycoside hydrolases from the hindgut bacterial symbionts of a termite (Trinervitermes trinervoides) and the characterization of a multimodular β-1,4-xylanase (GH11). Biotechnol Appl Biochem 2016; 64:174-186. [DOI: 10.1002/bab.1480] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 12/19/2015] [Indexed: 11/06/2022]
Affiliation(s)
| | - Walter Sanyika Tendai
- Biomanufacturing Centre; CSIR Biosciences; Pretoria South Africa
- Department of Biotechnology; Chinhoyi University of Technology; Chinhoyi Zimbabwe
| | - Kgama Mathiba
- Biomanufacturing Centre; CSIR Biosciences; Pretoria South Africa
| | - Thobile Ngcobo
- Biomanufacturing Centre; CSIR Biosciences; Pretoria South Africa
| | - Sibongile Mtimka
- Biomanufacturing Centre; CSIR Biosciences; Pretoria South Africa
| | - Dean Brady
- Biomanufacturing Centre; CSIR Biosciences; Pretoria South Africa
- Molecular Sciences Institute; School of Chemistry; University of the Witwatersrand; Johannesburg South Africa
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16
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Maruthamuthu M, Jiménez DJ, Stevens P, van Elsas JD. A multi-substrate approach for functional metagenomics-based screening for (hemi)cellulases in two wheat straw-degrading microbial consortia unveils novel thermoalkaliphilic enzymes. BMC Genomics 2016; 17:86. [PMID: 26822785 PMCID: PMC4730625 DOI: 10.1186/s12864-016-2404-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2015] [Accepted: 01/18/2016] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Functional metagenomics is a promising strategy for the exploration of the biocatalytic potential of microbiomes in order to uncover novel enzymes for industrial processes (e.g. biorefining or bleaching pulp). Most current methodologies used to screen for enzymes involved in plant biomass degradation are based on the use of single substrates. Moreover, highly diverse environments are used as metagenomic sources. However, such methods suffer from low hit rates of positive clones and hence the discovery of novel enzymatic activities from metagenomes has been hampered. RESULTS Here, we constructed fosmid libraries from two wheat straw-degrading microbial consortia, denoted RWS (bred on untreated wheat straw) and TWS (bred on heat-treated wheat straw). Approximately 22,000 clones from each library were screened for (hemi)cellulose-degrading enzymes using a multi-chromogenic substrate approach. The screens yielded 71 positive clones for both libraries, giving hit rates of 1:440 and 1:1,047 for RWS and TWS, respectively. Seven clones (NT2-2, T5-5, NT18-17, T4-1, 10BT, NT18-21 and T17-2) were selected for sequence analyses. Their inserts revealed the presence of 18 genes encoding enzymes belonging to twelve different glycosyl hydrolase families (GH2, GH3, GH13, GH17, GH20, GH27, GH32, GH39, GH53, GH58, GH65 and GH109). These encompassed several carbohydrate-active gene clusters traceable mainly to Klebsiella related species. Detailed functional analyses showed that clone NT2-2 (containing a beta-galactosidase of ~116 kDa) had highest enzymatic activity at 55 °C and pH 9.0. Additionally, clone T5-5 (containing a beta-xylosidase of ~86 kDa) showed > 90% of enzymatic activity at 55 °C and pH 10.0. CONCLUSIONS This study employed a high-throughput method for rapid screening of fosmid metagenomic libraries for (hemi)cellulose-degrading enzymes. The approach, consisting of screens on multi-substrates coupled to further analyses, revealed high hit rates, as compared with recent other studies. Two clones, 10BT and T4-1, required the presence of multiple substrates for detectable activity, indicating a new avenue in library activity screening. Finally, clones NT2-2, T5-5 and NT18-17 were found to encode putative novel thermo-alkaline enzymes, which could represent a starting point for further biotechnological applications.
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Affiliation(s)
- Mukil Maruthamuthu
- Department of Microbial Ecology, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747AG, Groningen, The Netherlands.
| | - Diego Javier Jiménez
- Department of Microbial Ecology, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747AG, Groningen, The Netherlands.
| | - Patricia Stevens
- Department of Microbial Ecology, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747AG, Groningen, The Netherlands.
| | - Jan Dirk van Elsas
- Department of Microbial Ecology, Groningen Institute for Evolutionary Life Sciences, University of Groningen, Nijenborgh 7, 9747AG, Groningen, The Netherlands.
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17
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Wei Y, Zhou H, Zhang J, Zhang L, Geng A, Liu F, Zhao G, Wang S, Zhou Z, Yan X. Insight into Dominant Cellulolytic Bacteria from Two Biogas Digesters and Their Glycoside Hydrolase Genes. PLoS One 2015; 10:e0129921. [PMID: 26070087 PMCID: PMC4466528 DOI: 10.1371/journal.pone.0129921] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 05/13/2015] [Indexed: 12/30/2022] Open
Abstract
Diverse cellulolytic bacteria are essential for maintaining high lignocellulose degradation ability in biogas digesters. However, little was known about functional genes and gene clusters of dominant cellulolytic bacteria in biogas digesters. This is the foundation to understand lignocellulose degradation mechanisms of biogas digesters and apply these gene resource for optimizing biofuel production. A combination of metagenomic and 16S rRNA gene clone library methods was used to investigate the dominant cellulolytic bacteria and their glycoside hydrolase (GH) genes in two biogas digesters. The 16S rRNA gene analysis revealed that the dominant cellulolytic bacteria were strains closely related to Clostridium straminisolvens and an uncultured cellulolytic bacterium designated BG-1. To recover GH genes from cellulolytic bacteria in general, and BG-1 in particular, a refined assembly approach developed in this study was used to assemble GH genes from metagenomic reads; 163 GH-containing contigs ≥ 1 kb in length were obtained. Six recovered GH5 genes that were expressed in E. coli demonstrated multiple lignocellulase activities and one had high mannanase activity (1255 U/mg). Eleven fosmid clones harboring the recovered GH-containing contigs were sequenced and assembled into 10 fosmid contigs. The composition of GH genes in the 163 assembled metagenomic contigs and 10 fosmid contigs indicated that diverse GHs and lignocellulose degradation mechanisms were present in the biogas digesters. In particular, a small portion of BG-1 genome information was recovered by PhyloPythiaS analysis. The lignocellulase gene clusters in BG-1 suggested that it might use a possible novel lignocellulose degradation mechanism to efficiently degrade lignocellulose. Dominant cellulolytic bacteria of biogas digester possess diverse GH genes, not only in sequences but also in their functions, which may be applied for production of biofuel in the future.
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Affiliation(s)
- Yongjun Wei
- CAS-Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Haokui Zhou
- Department of Microbiology, the Chinese University of Hong Kong, the Prince of Wales Hospital, Hong Kong, China
| | - Jun Zhang
- CAS-Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Lei Zhang
- CAS-Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Alei Geng
- CAS-Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Fanghua Liu
- CAS-Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Guoping Zhao
- CAS-Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
- Department of Microbiology, the Chinese University of Hong Kong, the Prince of Wales Hospital, Hong Kong, China
- Shanghai-MOST Key Laboratory for Health and Disease Genomics, Chinese National Human Genome Center, Shanghai, China
| | - Shengyue Wang
- Shanghai-MOST Key Laboratory for Health and Disease Genomics, Chinese National Human Genome Center, Shanghai, China
| | - Zhihua Zhou
- CAS-Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
- * E-mail: (XY); (ZZ)
| | - Xing Yan
- CAS-Key Laboratory of Synthetic Biology, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
- * E-mail: (XY); (ZZ)
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Kračun SK, Schückel J, Westereng B, Thygesen LG, Monrad RN, Eijsink VGH, Willats WGT. A new generation of versatile chromogenic substrates for high-throughput analysis of biomass-degrading enzymes. BIOTECHNOLOGY FOR BIOFUELS 2015; 8:70. [PMID: 25969695 PMCID: PMC4428106 DOI: 10.1186/s13068-015-0250-y] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 03/30/2015] [Indexed: 05/02/2023]
Abstract
BACKGROUND Enzymes that degrade or modify polysaccharides are widespread in pro- and eukaryotes and have multiple biological roles and biotechnological applications. Recent advances in genome and secretome sequencing, together with associated bioinformatic tools, have enabled large numbers of carbohydrate-acting enzymes to be putatively identified. However, there is a paucity of methods for rapidly screening the biochemical activities of these enzymes, and this is a serious bottleneck in the development of enzyme-reliant bio-refining processes. RESULTS We have developed a new generation of multi-coloured chromogenic polysaccharide and protein substrates that can be used in cheap, convenient and high-throughput multiplexed assays. In addition, we have produced substrates of biomass materials in which the complexity of plant cell walls is partially maintained. CONCLUSIONS We show that these substrates can be used to screen the activities of glycosyl hydrolases, lytic polysaccharide monooxygenases and proteases and provide insight into substrate availability within biomass. We envisage that the assays we have developed will be used primarily for first-level screening of large numbers of putative carbohydrate-acting enzymes, and the assays have the potential to be incorporated into fully or semi-automated robotic enzyme screening systems.
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Affiliation(s)
- Stjepan Krešimir Kračun
- />Department of Plant and Environmental Sciences, Thorvaldsensvej 40, Frederiksberg, C 1871 Denmark
| | - Julia Schückel
- />Department of Plant and Environmental Sciences, Thorvaldsensvej 40, Frederiksberg, C 1871 Denmark
| | - Bjørge Westereng
- />Department of Plant and Environmental Sciences, Thorvaldsensvej 40, Frederiksberg, C 1871 Denmark
- />Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Chr. M. Falsens vei 1., Aas, 1432 Norway
- />University of Copenhagen, Faculty of Science, Rolighedsvej 23, Frederiksberg, C 1958 Denmark
| | | | | | - Vincent G H Eijsink
- />Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Chr. M. Falsens vei 1., Aas, 1432 Norway
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D'haeseleer P, Gladden JM, Allgaier M, Chain PSG, Tringe SG, Malfatti SA, Aldrich JT, Nicora CD, Robinson EW, Paša-Tolić L, Hugenholtz P, Simmons BA, Singer SW. Proteogenomic analysis of a thermophilic bacterial consortium adapted to deconstruct switchgrass. PLoS One 2013; 8:e68465. [PMID: 23894306 PMCID: PMC3716776 DOI: 10.1371/journal.pone.0068465] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Accepted: 05/29/2013] [Indexed: 12/02/2022] Open
Abstract
Thermophilic bacteria are a potential source of enzymes for the deconstruction of lignocellulosic biomass. However, the complement of proteins used to deconstruct biomass and the specific roles of different microbial groups in thermophilic biomass deconstruction are not well-explored. Here we report on the metagenomic and proteogenomic analyses of a compost-derived bacterial consortium adapted to switchgrass at elevated temperature with high levels of glycoside hydrolase activities. Near-complete genomes were reconstructed for the most abundant populations, which included composite genomes for populations closely related to sequenced strains of Thermus thermophilus and Rhodothermus marinus, and for novel populations that are related to thermophilic Paenibacilli and an uncultivated subdivision of the little-studied Gemmatimonadetes phylum. Partial genomes were also reconstructed for a number of lower abundance thermophilic Chloroflexi populations. Identification of genes for lignocellulose processing and metabolic reconstructions suggested Rhodothermus, Paenibacillus and Gemmatimonadetes as key groups for deconstructing biomass, and Thermus as a group that may primarily metabolize low molecular weight compounds. Mass spectrometry-based proteomic analysis of the consortium was used to identify >3000 proteins in fractionated samples from the cultures, and confirmed the importance of Paenibacillus and Gemmatimonadetes to biomass deconstruction. These studies also indicate that there are unexplored proteins with important roles in bacterial lignocellulose deconstruction.
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Affiliation(s)
- Patrik D'haeseleer
- Joint BioEnergy Institute, Emeryville, California, United States of America.
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20
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Eichorst SA, Varanasi P, Stavila V, Zemla M, Auer M, Singh S, Simmons BA, Singer SW. Community dynamics of cellulose-adapted thermophilic bacterial consortia. Environ Microbiol 2013; 15:2573-87. [DOI: 10.1111/1462-2920.12159] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2013] [Revised: 04/29/2013] [Accepted: 05/15/2013] [Indexed: 12/01/2022]
Affiliation(s)
| | | | - Vatalie Stavila
- Biological and Materials Sciences Center; Sandia National Laboratories; Livermore; CA; 94551; USA
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21
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Wong MT, Zhang D, Li J, Hui RKH, Tun HM, Brar MS, Park TJ, Chen Y, Leung FC. Towards a metagenomic understanding on enhanced biomethane production from waste activated sludge after pH 10 pretreatment. BIOTECHNOLOGY FOR BIOFUELS 2013; 6:38. [PMID: 23506434 PMCID: PMC3607842 DOI: 10.1186/1754-6834-6-38] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2012] [Accepted: 03/06/2013] [Indexed: 05/04/2023]
Abstract
BACKGROUND Understanding the effects of pretreatment on anaerobic digestion of sludge waste from wastewater treatment plants is becoming increasingly important, as impetus moves towards the utilization of sludge for renewable energy production. Although the field of sludge pretreatment has progressed significantly over the past decade, critical questions concerning the underlying microbial interactions remain unanswered. In this study, a metagenomic approach was adopted to investigate the microbial composition and gene content contributing to enhanced biogas production from sludge subjected to a novel pretreatment method (maintaining pH at 10 for 8 days) compared to other documented methods (ultrasonic, thermal and thermal-alkaline). RESULTS Our results showed that pretreated sludge attained a maximum methane yield approximately 4-fold higher than that of the blank un-pretreated sludge set-up at day 17. Both the microbial and metabolic consortium shifted extensively towards enhanced biodegradation subsequent to pretreatment, providing insight for the enhanced methane yield. The prevalence of Methanosaeta thermophila and Methanothermobacter thermautotrophicus, together with the functional affiliation of enzymes-encoding genes suggested an acetoclastic and hydrogenotrophic methanogenesis pathway. Additionally, an alternative enzymology in Methanosaeta was observed. CONCLUSIONS This study is the first to provide a microbiological understanding of improved biogas production subsequent to a novel waste sludge pretreatment method. The knowledge garnered will assist the design of more efficient pretreatment methods for biogas production in the future.
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Affiliation(s)
- Mabel Ting Wong
- 5 N01, Kadoorie Biological Sciences Building, School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, Hong Kong
| | - Dong Zhang
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai, 200092, China
| | - Jun Li
- 5 N01, Kadoorie Biological Sciences Building, School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, Hong Kong
| | - Raymond Kin Hi Hui
- 5 N01, Kadoorie Biological Sciences Building, School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, Hong Kong
| | - Hein Min Tun
- 5 N01, Kadoorie Biological Sciences Building, School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, Hong Kong
| | - Manreetpal Singh Brar
- 5 N01, Kadoorie Biological Sciences Building, School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, Hong Kong
| | - Tae-Jin Park
- 5 N01, Kadoorie Biological Sciences Building, School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, Hong Kong
| | - Yinguang Chen
- State Key Laboratory of Pollution Control and Resources Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai, 200092, China
| | - Frederick C Leung
- 5 N01, Kadoorie Biological Sciences Building, School of Biological Sciences, The University of Hong Kong, Pokfulam Road, Hong Kong, Hong Kong
- Bioinformatics Center, Nanjing Agricultural University, Nanjing, China
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22
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Ghio S, Lorenzo GSD, Lia V, Talia P, Cataldi A, Grasso D, Campos E. Isolation of Paenibacillus sp. and Variovorax sp. strains from decaying woods and characterization of their potential for cellulose deconstruction. INTERNATIONAL JOURNAL OF BIOCHEMISTRY AND MOLECULAR BIOLOGY 2012; 3:352-364. [PMID: 23301200 PMCID: PMC3533884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Accepted: 12/03/2012] [Indexed: 06/01/2023]
Abstract
Prospection of cellulose-degrading bacteria in natural environments allows the identification of novel cellulases and hemicellulases that could be useful in second-generation bioethanol production. In this work, cellulolytic bacteria were isolated from decaying native forest soils by enrichment on cellulose as sole carbon source. There was a predominance of Gram positive isolates that belonged to the phyla Proteobacteria and Firmicutes. Many primary isolates with cellulolytic activity were not pure cultures. From these consortia, isolation of pure constituents was attempted in order to test the hypothesis whether microbial consortia are needed for full degradation of complex substrates. Two isolates, CB1-2-A-5 and VG-4-A-2, were obtained as the pure constituents of CB1-2 and VG-4 consortia, respectively. Based on 16S RNA sequence, they could be classified as Variovorax paradoxus and Paenibacillus alvei. Noteworthy, only VG-4 consortium showed measurable xylan degrading capacity and signs of filter paper degradation. However, no xylan or filter paper degrading capacities were observed for the pure cultures isolated from it, suggesting that other members of this consortium were necessary for these hydrolyzing activities. Our results indicated that Paenibacillus sp. and Variovorax sp. as well as VG-4 consortium, might be a useful source of hydrolytic enzymes. Moreover, although Variovorax sp. had been previously identified in metagenomic studies of cellulolytic communities, this is the first report on the isolation and characterization of this microorganism as a cellulolytic genus.
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Affiliation(s)
- Silvina Ghio
- Instituto de Suelos, CIRN, Inst. Nacional de Tecnología Agropecuaria (INTA)Dr. N. Repetto y Los Reseros s/n, 1686 Hurlingham, Buenos Aires, Argentina
| | - Gonzalo Sabarís Di Lorenzo
- Instituto de Biotecnología, CICVyA, Inst. Nacional de Tecnología Agropecuaria (INTA)Dr. N. Repetto y Los Reseros s/n, 1686 Hurlingham, Buenos Aires, Argentina
| | - Verónica Lia
- Instituto de Biotecnología, CICVyA, Inst. Nacional de Tecnología Agropecuaria (INTA)Dr. N. Repetto y Los Reseros s/n, 1686 Hurlingham, Buenos Aires, Argentina
| | - Paola Talia
- Instituto de Biotecnología, CICVyA, Inst. Nacional de Tecnología Agropecuaria (INTA)Dr. N. Repetto y Los Reseros s/n, 1686 Hurlingham, Buenos Aires, Argentina
| | - Angel Cataldi
- Instituto de Biotecnología, CICVyA, Inst. Nacional de Tecnología Agropecuaria (INTA)Dr. N. Repetto y Los Reseros s/n, 1686 Hurlingham, Buenos Aires, Argentina
| | - Daniel Grasso
- Instituto de Suelos, CIRN, Inst. Nacional de Tecnología Agropecuaria (INTA)Dr. N. Repetto y Los Reseros s/n, 1686 Hurlingham, Buenos Aires, Argentina
| | - Eleonora Campos
- Instituto de Biotecnología, CICVyA, Inst. Nacional de Tecnología Agropecuaria (INTA)Dr. N. Repetto y Los Reseros s/n, 1686 Hurlingham, Buenos Aires, Argentina
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Vey G, Moreno-Hagelsieb G. Metagenomic annotation networks: construction and applications. PLoS One 2012; 7:e41283. [PMID: 22879885 PMCID: PMC3413691 DOI: 10.1371/journal.pone.0041283] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Accepted: 06/19/2012] [Indexed: 12/20/2022] Open
Abstract
The derivation and comparison of biological interaction networks are vital for understanding the functional capacity and hierarchical organization of integrated microbial communities. In the current work we present metagenomic annotation networks as a novel taxonomy-free approach for understanding the functional architecture of metagenomes. Specifically, metagenomic operon predictions are exploited to derive functional interactions that are translated and categorized according to their associated functional annotations. The result is a collection of discrete networks of weighted annotation linkages. These networks are subsequently examined for the occurrence of annotation modules that portray the functional and organizational characteristics of various microbial communities. A variety of network perspectives and annotation categories are applied to recover a diverse range of modules with different degrees of annotative cohesiveness. Applications to biocatalyst discovery and human health issues are discussed, as well as the limitations of the current implementation.
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Affiliation(s)
- Gregory Vey
- Department of Biology, University of Waterloo, Waterloo, Ontario, Canada
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24
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van der Lelie D, Taghavi S, McCorkle SM, Li LL, Malfatti SA, Monteleone D, Donohoe BS, Ding SY, Adney WS, Himmel ME, Tringe SG. The metagenome of an anaerobic microbial community decomposing poplar wood chips. PLoS One 2012; 7:e36740. [PMID: 22629327 PMCID: PMC3357426 DOI: 10.1371/journal.pone.0036740] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2011] [Accepted: 04/11/2012] [Indexed: 02/01/2023] Open
Abstract
This study describes the composition and metabolic potential of a lignocellulosic biomass degrading community that decays poplar wood chips under anaerobic conditions. We examined the community that developed on poplar biomass in a non-aerated bioreactor over the course of a year, with no microbial inoculation other than the naturally occurring organisms on the woody material. The composition of this community contrasts in important ways with biomass-degrading communities associated with higher organisms, which have evolved over millions of years into a symbiotic relationship. Both mammalian and insect hosts provide partial size reduction, chemical treatments (low or high pH environments), and complex enzymatic ‘secretomes’ that improve microbial access to cell wall polymers. We hypothesized that in order to efficiently degrade coarse untreated biomass, a spontaneously assembled free-living community must both employ alternative strategies, such as enzymatic lignin depolymerization, for accessing hemicellulose and cellulose and have a much broader metabolic potential than host-associated communities. This would suggest that such a community would make a valuable resource for finding new catalytic functions involved in biomass decomposition and gaining new insight into the poorly understood process of anaerobic lignin depolymerization. Therefore, in addition to determining the major players in this community, our work specifically aimed at identifying functions potentially involved in the depolymerization of cellulose, hemicelluloses, and lignin, and to assign specific roles to the prevalent community members in the collaborative process of biomass decomposition. A bacterium similar to Magnetospirillum was identified among the dominant community members, which could play a key role in the anaerobic breakdown of aromatic compounds. We suggest that these compounds are released from the lignin fraction in poplar hardwood during the decay process, which would point to lignin-modification or depolymerization under anaerobic conditions.
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Affiliation(s)
- Daniel van der Lelie
- Biology Department, Brookhaven National Laboratory, Upton, New York, United States of America.
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25
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Wei H, Tucker MP, Baker JO, Harris M, Luo Y, Xu Q, Himmel ME, Ding SY. Tracking dynamics of plant biomass composting by changes in substrate structure, microbial community, and enzyme activity. BIOTECHNOLOGY FOR BIOFUELS 2012; 5:20. [PMID: 22490508 PMCID: PMC3384452 DOI: 10.1186/1754-6834-5-20] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Accepted: 04/10/2012] [Indexed: 05/07/2023]
Abstract
BACKGROUND Understanding the dynamics of the microbial communities that, along with their secreted enzymes, are involved in the natural process of biomass composting may hold the key to breaking the major bottleneck in biomass-to-biofuels conversion technology, which is the still-costly deconstruction of polymeric biomass carbohydrates to fermentable sugars.However, the complexity of both the structure of plant biomass and its counterpart microbial degradation communities makes it difficult to investigate the composting process. RESULTS In this study, a composter was set up with a mix of yellow poplar (Liriodendron tulipifera) wood-chips and mown lawn grass clippings (85:15 in dry-weight) and used as a model system. The microbial rDNA abundance data obtained from analyzing weekly-withdrawn composted samples suggested population-shifts from bacteria-dominated to fungus-dominated communities. Further analyses by an array of optical microscopic, transcriptional and enzyme-activity techniques yielded correlated results, suggesting that such population shifts occurred along with early removal of hemicellulose followed by attack on the consequently uncovered cellulose as the composting progressed. CONCLUSION The observed shifts in dominance by representative microbial groups, along with the observed different patterns in the gene expression and enzymatic activities between cellulases, hemicellulases, and ligninases during the composting process, provide new perspectives for biomass-derived biotechnology such as consolidated bioprocessing (CBP) and solid-state fermentation for the production of cellulolytic enzymes and biofuels.
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Affiliation(s)
- Hui Wei
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Melvin P Tucker
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - John O Baker
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Michelle Harris
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Yonghua Luo
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Qi Xu
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Michael E Himmel
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Shi-You Ding
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
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26
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Thomas MF, Li LL, Handley-Pendleton JM, van der Lelie D, Dunn JJ, Wishart JF. Enzyme activity in dialkyl phosphate ionic liquids. BIORESOURCE TECHNOLOGY 2011; 102:11200-11203. [PMID: 22001053 DOI: 10.1016/j.biortech.2011.09.069] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Revised: 09/15/2011] [Accepted: 09/16/2011] [Indexed: 05/31/2023]
Abstract
The activity of four metagenomic enzymes and an enzyme cloned from the straw mushroom, Volvariella volvacea were studied in the following ionic liquids, 1,3-dimethylimidazolium dimethyl phosphate, [mmim][dmp], 1-ethyl-3-methylimidazolium dimethyl phosphate, [emim][dmp], 1-ethyl-3-methylimidazolium diethyl phosphate, [emim][dep] and 1-ethyl-3-methylimidazolium acetate, [emim][OAc]. Activity was determined by analyzing the hydrolysis of para-nitrobenzene carbohydrate derivatives. In general, the enzymes were most active in the dimethyl phosphate ionic liquids, followed by acetate. Generally speaking, activity decreased sharply for concentrations of [emim][dep] above 10% v/v, while the other ionic liquids showed less impact on activity up to 20% v/v.
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Affiliation(s)
- Marie F Thomas
- Department of Chemistry, Brookhaven National Laboratory, P.O. Box 5000, Upton, NY 11973, USA.
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