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Singh S, Singh S, Lukas SB, Machado S, Nouri A, Calderon F, Rieke ER, Cappellazzi SB. Long-term agro-management strategies shape soil bacterial community structure in dryland wheat systems. Sci Rep 2023; 13:13929. [PMID: 37626146 PMCID: PMC10457325 DOI: 10.1038/s41598-023-41216-z] [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: 08/28/2022] [Accepted: 08/23/2023] [Indexed: 08/27/2023] Open
Abstract
Soil microbes play a crucial role in soil organic matter decomposition and nutrient cycling and are influenced by management practices. Therefore, quantifying the impacts of various agricultural management practices on soil microbiomes and their activity is crucial for making informed management decisions. This study aimed to assess the impact of various management systems on soil bacterial abundance and diversity, soil enzyme activities and carbon mineralization potential in wheat-based systems. To accomplish this, soil samples from 0 to 15 cm depth were collected from ongoing long-term field trials in eastern Oregon region under wheat (Triticum aestivum L.)-fallow (WF), WF with different tillage (WT), wheat-pea (Pisum sativum L.) (WP), WF under different crop residue management (CR) and natural undisturbed/unmanaged grassland pasture (GP). These trials consisted of an array of treatments like tillage intensities, nitrogen rates, organic amendments, and seasonal residue burning. This study was a part of the Soil Health Institute's North American Project to Evaluate Soil Health measurements (NAPESHM). Bacterial community structure was determined using amplicon sequencing of the V4 region of 16SrRNA genes and followed the protocols of the Earth Microbiome Project. In addition, extracellular enzyme activities, and carbon mineralization potential (1d-CO2) were measured. Among different trials, 1d-CO2 in WT, WP, and CR studies averaged 53%, 51% and 87% lower than GP systems, respectively. Enzyme activities were significantly greater in GP compared to the other managements and followed similar trend as respiration. We observed higher evenness in GP and higher richness in spring residue burning treatment of CR study. Our results indicated that species evenness is perhaps a better indicator of soil health in comparison to other indices in dryland wheat systems.
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Affiliation(s)
- Shikha Singh
- Hermiston Agricultural Research and Extension Center, Oregon State University, 2121 S 1St, Hermiston, OR, 97838, USA
| | - Surendra Singh
- Columbia Basin Agricultural Research Center, Oregon State University, 48037 Tubbs Ranch Rd., Adams, OR, 97810, USA
| | - Scott B Lukas
- Hermiston Agricultural Research and Extension Center, Oregon State University, 2121 S 1St, Hermiston, OR, 97838, USA.
| | - Stephen Machado
- Columbia Basin Agricultural Research Center, Oregon State University, 48037 Tubbs Ranch Rd., Adams, OR, 97810, USA
| | - Amin Nouri
- Hermiston Agricultural Research and Extension Center, Oregon State University, 2121 S 1St, Hermiston, OR, 97838, USA
| | - Francisco Calderon
- Columbia Basin Agricultural Research Center, Oregon State University, 48037 Tubbs Ranch Rd., Adams, OR, 97810, USA
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Zhu K, Jia W, Mei Y, Wu S, Huang P. Shift from flooding to drying enhances the respiration of soil aggregates by changing microbial community composition and keystone taxa. Front Microbiol 2023; 14:1167353. [PMID: 37250047 PMCID: PMC10214030 DOI: 10.3389/fmicb.2023.1167353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2023] [Accepted: 04/19/2023] [Indexed: 05/31/2023] Open
Abstract
Changes in the water regime are among the crucial factors controlling soil carbon dynamics. However, at the aggregate scale, the microbial mechanisms that regulate soil respiration under flooding and drying conditions are obscure. In this research, we investigated how the shift from flooding to drying changes the microbial respiration of soil aggregates by affecting microbial community composition and their co-occurrence patterns. Soils collected from a riparian zone of the Three Gorges Reservoir, China, were subjected to a wet-and-dry incubation experiment. Our data illustrated that the shift from flooding to drying substantially enhanced soil respiration for all sizes of aggregate fractions. Moreover, soil respiration declined with aggregate size in both flooding and drying treatments. The keystone taxa in bacterial networks were found to be Acidobacteriales, Gemmatimonadales, Anaerolineales, and Cytophagales during the flooding treatment, and Rhizobiales, Gemmatimonadales, Sphingomonadales, and Solirubrobacterales during the drying treatment. For fungal networks, Hypocreales and Agaricalesin were the keystone taxa in the flooding and drying treatments, respectively. Furthermore, the shift from flooding to drying enhanced the microbial respiration of soil aggregates by changing keystone taxa. Notably, fungal community composition and network properties dominated the changes in the microbial respiration of soil aggregates during the shift from flooding to drying. Thus, our study highlighted that the shift from flooding to drying changes keystone taxa, hence increasing aggregate-scale soil respiration.
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Verma D, Satyanarayana T. Xylanolytic Extremozymes Retrieved From Environmental Metagenomes: Characteristics, Genetic Engineering, and Applications. Front Microbiol 2020; 11:551109. [PMID: 33042057 PMCID: PMC7527525 DOI: 10.3389/fmicb.2020.551109] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Accepted: 08/21/2020] [Indexed: 01/29/2023] Open
Abstract
Xylanolytic enzymes have extensive applications in paper, food, and feed, pharmaceutical, and biofuel industries. These industries demand xylanases that are functional under extreme conditions, such as high temperature, acidic/alkaline pH, and others, which are prevailing in bioprocessing industries. Despite the availability of several xylan-hydrolyzing enzymes from cultured microbes, there is a huge gap between what is available and what industries require. DNA manipulations as well as protein-engineering techniques are also not quite satisfactory in generating xylan-hydrolyzing extremozymes. With a compound annual growth rate of 6.6% of xylan-hydrolyzing enzymes in the global market, there is a need for xylanolytic extremozymes. Therefore, metagenomic approaches have been employed to uncover hidden xylanolytic genes that were earlier inaccessible in culture-dependent approaches. Appreciable success has been achieved in retrieving several unusual xylanolytic enzymes with novel and desirable characteristics from different extreme environments using functional and sequence-based metagenomic approaches. Moreover, the Carbohydrate Active Enzymes database includes approximately 400 GH-10 and GH-11 unclassified xylanases. This review discusses sources, characteristics, and applications of xylanolytic enzymes obtained through metagenomic approaches and their amelioration by genetic engineering techniques.
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Affiliation(s)
- Digvijay Verma
- Department of Microbiology, Babasaheb Bhimrao Ambedkar (Central) University, Lucknow, India
| | - Tulasi Satyanarayana
- Department of Biological Sciences and Engineering, Netaji Subhas University of Technology, Dwarka, New Delhi, India
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Berger T, Poyntner C, Margesin R. Culturable bacteria from an Alpine coniferous forest site: biodegradation potential of organic polymers and pollutants. Folia Microbiol (Praha) 2020; 66:87-98. [PMID: 32975726 PMCID: PMC7854452 DOI: 10.1007/s12223-020-00825-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 09/16/2020] [Indexed: 01/16/2023]
Abstract
The potential of the culturable bacterial community from an Alpine coniferous forest site for the degradation of organic polymers and pollutants at low (5 °C) and moderate (20 °C) temperatures was evaluated. The majority of the 68 strains belonged to the phylum Proteobacteria (77%). Other strains were related to Bacteroidetes (12%), Alphaproteobacteria (4%), Actinobacteria (3%), and Firmicutes (3%). The strains were grouped into 42 different OTUs. The highest bacterial diversity was found within the phylum Bacteroidetes. All strains, except one, could grow at temperatures from 5 to 25 °C. The production of enzyme activities involved in the degradation of organic polymers present in plant litter (carboxymethyl cellulose, microgranular cellulose, xylan, polygalacturonic acid) was almost comparable at 5 °C (68%) and 20 °C (63%). Utilizers of lignin compounds (lignosulfonic acid, lignin alkali) as sole carbon source were found to a higher extent at 20 °C (57%) than at 5 °C (24%), but the relative fractions among positively tested strains utilizing these compounds were almost identical at the two temperatures. Similar results were noted for utilizers of organic pollutants (n-hexadecane, diesel oil, phenol, glyphosate) as sole carbon source. More than two-thirds showed constitutively expressed catechol-1,2-dioxygenase activity both at 5 °C (74%) and 20 °C (66%). Complete phenol (2.5 mmol/L) degradation by strain Paraburkholderia aromaticivorans AR20-38 was demonstrated at 0-30 °C, amounts up to 7.5 mmol/L phenol were fully degraded at 10-30 °C. These results are useful to better understand the effect of changing temperatures on microorganisms involved in litter degradation and nutrient turnover in Alpine forest soils.
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Affiliation(s)
- Tanja Berger
- Institute of Microbiology, University of Innsbruck, Technikerstrasse 25, 6020, Innsbruck, Austria
| | - Caroline Poyntner
- Institute of Microbiology, University of Innsbruck, Technikerstrasse 25, 6020, Innsbruck, Austria
| | - Rosa Margesin
- Institute of Microbiology, University of Innsbruck, Technikerstrasse 25, 6020, Innsbruck, Austria.
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Donhauser J, Frey B. Alpine soil microbial ecology in a changing world. FEMS Microbiol Ecol 2019; 94:5017441. [PMID: 30032189 DOI: 10.1093/femsec/fiy099] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 05/25/2018] [Indexed: 01/22/2023] Open
Abstract
Climate change has a disproportionally large impact on alpine soil ecosystems, leading to pronounced changes in soil microbial diversity and function associated with effects on biogeochemical processes at the local and supraregional scales. However, due to restricted accessibility, high-altitude soils remain largely understudied and a considerable heterogeneity hampers the comparability of different alpine studies. Here, we highlight differences and similarities between alpine and arctic ecosystems, and we discuss the impact of climatic variables and associated vegetation and soil properties on microbial ecology. We consider how microbial alpha-diversity, community structures and function change along altitudinal gradients and with other topographic features such as slope aspect. In addition, we focus on alpine permafrost soils, harboring a surprisingly large unknown microbial diversity and on microbial succession along glacier forefield chronosequences constituting the most thoroughly studied alpine habitat. Finally, highlighting experimental approaches, we present climate change studies showing shifts in microbial community structures and function in response to warming and altered moisture, interestingly with some contradiction. Collectively, despite harsh environmental conditions, many specially adapted microorganisms are able to thrive in alpine environments. Their community structures strongly correlate with climatic, vegetation and soil properties and thus closely mirror the complexity and small-scale heterogeneity of alpine soils.
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Affiliation(s)
| | - Beat Frey
- Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
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High-throughput amplicon sequencing demonstrates extensive diversity of xylanase genes in the sediment of soda lake Dabusu. Biotechnol Lett 2019; 41:409-418. [PMID: 30644013 DOI: 10.1007/s10529-019-02646-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 01/09/2019] [Indexed: 10/27/2022]
Abstract
OBJECTIVE To explore the diversity of glycoside hydrolase family 10 xylanase genes in the sediment of soda lake Dabusu by using high-throughput amplicon sequencing based on the Illumina HiSeq2500 platform. RESULTS A total of 227,420 clean reads, representing approximately 49.5 M bp, were obtained. Operational taxonomic unit (OTU) classification, with a 95% sequence identity cut-off, resulted in 467 OTUs with 392 annotated as GH10 xylanase, exhibiting 35-99% protein sequence identity with their closest-related xylanases in GenBank. Above 75% of the total OTUs demonstrated less than 80% identity with known xylanases. In addition, xylanases derived from the sediment were found to be affiliated to 12 different phyla, with Bacteroidetes, Proteobacteria, Actinobacteria, Firmicutes, Verrucomicrobia, and Basidiomycota being the dominant phyla. Moreover, barcode sequence had a major effect on abundance with only a minor effect on diversity. CONCLUSIONS High-throughput amplicon sequencing offers insight into xylanase gene diversity at a substantially higher resolution and lesser cost than library cloning and Sanger sequencing, facilitating a more thorough understanding of xylanase distribution and ecology.
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Wu J, Qiu C, Ren Y, Yan R, Ye X, Wang G. Novel Salt-Tolerant Xylanase from a Mangrove-Isolated Fungus Phoma sp. MF13 and Its Application in Chinese Steamed Bread. ACS OMEGA 2018; 3:3708-3716. [PMID: 30023876 PMCID: PMC6045339 DOI: 10.1021/acsomega.8b00345] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 03/22/2018] [Indexed: 05/28/2023]
Abstract
A novel glycosyl hydrolase family 11 xylanase gene, xynMF13A, was cloned from Phoma sp. MF13, a xylanase-producing fungus isolated from mangrove sediment. xynMF13A was heterologously expressed in Pichia pastoris, and the recombinant XynMF13A (rXynMF13A) was purified by Ni-affinity chromatography. The temperature and pH optima of purified rXynMF13A were 45 °C and pH 5.0, respectively. rXynMF13A showed a high level of salt tolerance, with maximal enzyme activity being seen at 0.5 M NaCl and as much as 53% of maximal activity at 4 M NaCl. The major rXynMF13A hydrolysis products from corncob xylan were xylobiose, xylotriose, xylotetraose, and xylopentaose, but no xylose was found. These hydrolysis products suggest an important potential for XynMF13A in the production of xylooligosaccharides (XOs). Furthermore, rXynMF13A had beneficial effects on Chinese steamed bread production, by increasing specific volume and elasticity while decreasing hardness and chewiness. These results demonstrate XynMF13A to be a novel xylanase with potentially significant applications in baking, XOs production, and seafood processing.
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8
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Genetic diversity detection and gene discovery of novel glycoside hydrolase family 48 from soil environmental genomic DNA. ANN MICROBIOL 2018. [DOI: 10.1007/s13213-018-1327-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
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Heterologous expression in Pichia pastoris and characterization of a novel GH11 xylanase from saline-alkali soil with excellent tolerance to high pH, high salt concentrations and ethanol. Protein Expr Purif 2017; 139:71-77. [DOI: 10.1016/j.pep.2017.06.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Revised: 05/17/2017] [Accepted: 06/06/2017] [Indexed: 11/22/2022]
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10
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Qiu H, Li Z, Wang H, Zhang H, Li S, Luo X, Song Y, Wang N, He H, Zhou H, Ma W, Zhang T. Molecular and biochemical characterization of a novel cold-active and metal ion-tolerant GH10 xylanase from frozen soil. BIOTECHNOL BIOTEC EQ 2017. [DOI: 10.1080/13102818.2017.1359667] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Affiliation(s)
- Haiyan Qiu
- Key Lab of Industrial Fermentation Microbiology (Tianjin University of Science and Technology), Ministry of Education, Tianjin, P.R. China
- Tianjin Key Lab of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, P.R. China
| | - Zhongyuan Li
- Key Lab of Industrial Fermentation Microbiology (Tianjin University of Science and Technology), Ministry of Education, Tianjin, P.R. China
- Tianjin Key Lab of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, P.R. China
- Key laboratory of Feed Biotechnology, The Ministry of Agriculture of the People's Republic of China, Beijing, 100081, P.R. China
| | - Hui Wang
- Key Lab of Industrial Fermentation Microbiology (Tianjin University of Science and Technology), Ministry of Education, Tianjin, P.R. China
- Tianjin Key Lab of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, P.R. China
| | - Haiying Zhang
- Key Lab of Industrial Fermentation Microbiology (Tianjin University of Science and Technology), Ministry of Education, Tianjin, P.R. China
- Tianjin Key Lab of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, P.R. China
| | - Shuang Li
- Key Lab of Industrial Fermentation Microbiology (Tianjin University of Science and Technology), Ministry of Education, Tianjin, P.R. China
- Tianjin Key Lab of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, P.R. China
| | - Xuegang Luo
- Key Lab of Industrial Fermentation Microbiology (Tianjin University of Science and Technology), Ministry of Education, Tianjin, P.R. China
- Tianjin Key Lab of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, P.R. China
| | - Yajian Song
- Key Lab of Industrial Fermentation Microbiology (Tianjin University of Science and Technology), Ministry of Education, Tianjin, P.R. China
- Tianjin Key Lab of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, P.R. China
| | - Nan Wang
- Key Lab of Industrial Fermentation Microbiology (Tianjin University of Science and Technology), Ministry of Education, Tianjin, P.R. China
- Tianjin Key Lab of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, P.R. China
| | - Hongpeng He
- Key Lab of Industrial Fermentation Microbiology (Tianjin University of Science and Technology), Ministry of Education, Tianjin, P.R. China
- Tianjin Key Lab of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, P.R. China
| | - Hao Zhou
- Key Lab of Industrial Fermentation Microbiology (Tianjin University of Science and Technology), Ministry of Education, Tianjin, P.R. China
- Tianjin Key Lab of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, P.R. China
| | - Wenjian Ma
- Key Lab of Industrial Fermentation Microbiology (Tianjin University of Science and Technology), Ministry of Education, Tianjin, P.R. China
- Tianjin Key Lab of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, P.R. China
| | - Tongcun Zhang
- Key Lab of Industrial Fermentation Microbiology (Tianjin University of Science and Technology), Ministry of Education, Tianjin, P.R. China
- Tianjin Key Lab of Industrial Microbiology, College of Biotechnology, Tianjin University of Science and Technology, Tianjin, P.R. China
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Wang G, Wu J, Yan R, Lin J, Ye X. A Novel Multi-domain High Molecular, Salt-Stable Alkaline Xylanase from Alkalibacterium sp. SL3. Front Microbiol 2017; 7:2120. [PMID: 28101084 PMCID: PMC5209378 DOI: 10.3389/fmicb.2016.02120] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 12/15/2016] [Indexed: 11/13/2022] Open
Abstract
A novel multi-domain high molecular xylanase coding gene (xynSL3) was cloned from Alkalibacterium sp. SL3, an alkaliphilic bacterial strain isolated from the sediment of soda lake Dabusu. The deduced XynSL3 is composed of a putative signal peptide, three tandem domains of carbohydrate binding module (CBM) family 22, a catalytic domain of glycosyl hydrolase (GH) family 10 and a domain of CBM9. XynSL3 shares the highest identity of 66% to a hypothetical protein from Alkalibacterium sp. AK22 and has low identities (33-45%) with other functionally characterized xylanases. The gene xynSL3 was expressed heterologously in Escherichia coli and the recombinant enzyme demonstrated some particular characteristics. Purified recombinant XynSL3 (rXynSL3) was highly active and stable over the neutral and alkaline pH ranges from 7.0 to 12.0, with maximum activity at pH 9.0 and around 45% activity at pH 12.0. It had an apparent temperature optimum of 55°C and was stable at 50°C. The rXynSL3 was highly halotolerant, retaining more than 60% activity with 3 M NaCl and was stable at up to a 4 M concentration of NaCl. The hydrolysis products of rXynSL3 from corncob xylan were mainly xylobiose and xylotetraose. The activity of rXynSL3 was enhanced by Ca2+ and it has strong resistance to sodium dodecyl sulfate (SDS). This multi-domain, alkaline and salt-tolerant enzyme has great potential for basic research and industrial applications such as the biobleaching of paper pulp and production of xylo-oligosaccharides (XOS).
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Affiliation(s)
- Guozeng Wang
- Fujian Key Laboratory of Marine Enzyme Engineering, Fuzhou UniversityFuzhou, China; College of Biological Science and Technology, Fuzhou UniversityFuzhou, China
| | - Jingjing Wu
- Fujian Key Laboratory of Marine Enzyme Engineering, Fuzhou UniversityFuzhou, China; College of Biological Science and Technology, Fuzhou UniversityFuzhou, China
| | - Renxiang Yan
- College of Biological Science and Technology, Fuzhou University Fuzhou, China
| | - Juan Lin
- Fujian Key Laboratory of Marine Enzyme Engineering, Fuzhou UniversityFuzhou, China; College of Biological Science and Technology, Fuzhou UniversityFuzhou, China
| | - Xiuyun Ye
- Fujian Key Laboratory of Marine Enzyme Engineering, Fuzhou UniversityFuzhou, China; College of Biological Science and Technology, Fuzhou UniversityFuzhou, China
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13
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Manoharan L, Kushwaha SK, Hedlund K, Ahrén D. Captured metagenomics: large-scale targeting of genes based on 'sequence capture' reveals functional diversity in soils. DNA Res 2015; 22:451-60. [PMID: 26490729 PMCID: PMC4675713 DOI: 10.1093/dnares/dsv026] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Accepted: 09/28/2015] [Indexed: 01/09/2023] Open
Abstract
Microbial enzyme diversity is a key to understand many ecosystem processes. Whole metagenome sequencing (WMG) obtains information on functional genes, but it is costly and inefficient due to large amount of sequencing that is required. In this study, we have applied a captured metagenomics technique for functional genes in soil microorganisms, as an alternative to WMG. Large-scale targeting of functional genes, coding for enzymes related to organic matter degradation, was applied to two agricultural soil communities through captured metagenomics. Captured metagenomics uses custom-designed, hybridization-based oligonucleotide probes that enrich functional genes of interest in metagenomic libraries where only probe-bound DNA fragments are sequenced. The captured metagenomes were highly enriched with targeted genes while maintaining their target diversity and their taxonomic distribution correlated well with the traditional ribosomal sequencing. The captured metagenomes were highly enriched with genes related to organic matter degradation; at least five times more than similar, publicly available soil WMG projects. This target enrichment technique also preserves the functional representation of the soils, thereby facilitating comparative metagenomics projects. Here, we present the first study that applies the captured metagenomics approach in large scale, and this novel method allows deep investigations of central ecosystem processes by studying functional gene abundances.
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Affiliation(s)
| | - Sandeep K Kushwaha
- Department of Biology, Lund University, Lund 223 62, Sweden Bioinformatics Infrastructure for Life Sciences (BILS), Lund University, Lund, Sweden PlantLink, Swedish University of Agriculture Sciences, Alnarp, Sweden
| | | | - Dag Ahrén
- Department of Biology, Lund University, Lund 223 62, Sweden Bioinformatics Infrastructure for Life Sciences (BILS), Lund University, Lund, Sweden
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Liu Y, Rainey PB, Zhang XX. Molecular mechanisms of xylose utilization by Pseudomonas fluorescens: overlapping genetic responses to xylose, xylulose, ribose and mannitol. Mol Microbiol 2015; 98:553-70. [PMID: 26194109 DOI: 10.1111/mmi.13142] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/17/2015] [Indexed: 02/03/2023]
Abstract
Bacterial degradation of xylose is sequentially mediated by two enzymes - an isomerase (XutA) and a xylulokinase (XutB) - with xylulose as an intermediate. Pseudomonas fluorescens SBW25, though capable of growth on xylose as a sole carbon source, encodes only one degradative enzyme XutA at the xylose utilization (xut) locus. Here, using site-directed mutagenesis and transcriptional assays, we have identified two functional xylulokinase-encoding genes (xutB1 and xutB2) and further show that expression of xutB1 is specifically induced by xylose. Surprisingly, xylose-induced xutB1 expression is mediated by the mannitol-responsive regulator MtlR, using xylulose rather than xylose as the direct inducer. In contrast, expression of the xutA operon is regulated by XutR - a transcriptional activator of the AraC family - in a xylose-, xylulose- and ribose-dependent manner. Detailed genetic and biochemical analyses of XutR, including DNase I footprinting assays, suggest an unconventional model of XutR regulation that does not involve DNA-looping, a mechanism typically found for AraC-type regulators from enteric bacteria. XutR functions as a dimer and recognizes two inverted repeat sequences, but binding to one half site is weak thus requiring an inducer molecule such as xylose for activation.
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Affiliation(s)
- Yunhao Liu
- Institute of Natural and Mathematical Sciences, Massey University, Auckland, 0745, New Zealand.,NZ Institute for Advanced Study, Massey University, Auckland, 0745, New Zealand
| | - Paul B Rainey
- NZ Institute for Advanced Study, Massey University, Auckland, 0745, New Zealand.,Max Planck Institute for Evolutionary Biology, Plön, 24306, Germany
| | - Xue-Xian Zhang
- Institute of Natural and Mathematical Sciences, Massey University, Auckland, 0745, New Zealand
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15
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High Genetic Diversity of Microbial Cellulase and Hemicellulase Genes in the Hindgut of Holotrichia parallela Larvae. Int J Mol Sci 2015. [PMID: 26197317 PMCID: PMC4519965 DOI: 10.3390/ijms160716545] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
In this study, we used a culture-independent method based on library construction and sequencing to analyze the genetic diversity of the cellulase and hemicellulase genes of the bacterial community resident in the hindgut of Holotrichia parallela larvae. The results indicate that there is a large, diverse set of bacterial genes encoding lignocellulose hydrolysis enzymes in the hindgut of H. parallela. The total of 101 distinct gene fragments (similarity <95%) of glycosyl hydrolase families including GH2 (24 genes), GH8 (27 genes), GH10 (19 genes), GH11 (14 genes) and GH36 (17 genes) families was retrieved, and certain sequences of GH2 (10.61%), GH8 (3.33%), and GH11 (18.42%) families had <60% identities with known sequences in GenBank, indicating their novelty. Based on phylogenetic analysis, sequences from hemicellulase families were related to enzymes from Bacteroidetes and Firmicutes. Fragments from cellulase family were most associated with the phylum of Proteobacteria. Furthermore, a full-length endo-xylanase gene was obtained, and the enzyme exhibited activity over a broad range of pH levels. Our results indicate that there are large number of cellulolytic and xylanolytic bacteria in the hindgut of H. parallela larvae, and these symbiotic bacteria play an important role in the degradation of roots and other organic matter for the host insect.
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16
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Sun MZ, Zheng HC, Meng LC, Sun JS, Song H, Bao YJ, Pei HS, Yan Z, Zhang XQ, Zhang JS, Liu YH, Lu FP. Direct cloning, expression of a thermostable xylanase gene from the metagenomic DNA of cow dung compost and enzymatic production of xylooligosaccharides from corncob. Biotechnol Lett 2015; 37:1877-86. [DOI: 10.1007/s10529-015-1857-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 05/06/2015] [Indexed: 10/23/2022]
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17
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Wang G, Huang X, Ng TB, Lin J, Ye XY. High phylogenetic diversity of glycosyl hydrolase family 10 and 11 xylanases in the sediment of Lake Dabusu in China. PLoS One 2014; 9:e112798. [PMID: 25392912 PMCID: PMC4231106 DOI: 10.1371/journal.pone.0112798] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 10/15/2014] [Indexed: 11/19/2022] Open
Abstract
Soda lakes are one of the most stable naturally occurring alkaline and saline environments, which harbor abundant microorganisms with diverse functions. In this study, culture-independent molecular methods were used to explore the genetic diversity of glycoside hydrolase (GH) family 10 and GH11 xylanases in Lake Dabusu, a soda lake with a pH value of 10.2 and salinity of 10.1%. A total of 671 xylanase gene fragments were obtained, representing 78 distinct GH10 and 28 GH11 gene fragments respectively, with most of them having low homology with known sequences. Phylogenetic analysis revealed that the GH10 xylanase sequences mainly belonged to Bacteroidetes, Proteobacteria, Actinobacteria, Firmicutes and Verrucomicrobia, while the GH11 sequences mainly consisted of Actinobacteria, Firmicutes and Fungi. A full-length GH10 xylanase gene (xynAS10-66) was directly cloned and expressed in Escherichia coli, and the recombinant enzymes showed high activity at alkaline pH. These results suggest that xylanase gene diversity within Lake Dabusu is high and that most of the identified genes might be novel, indicating great potential for applications in industry and agriculture.
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Affiliation(s)
- Guozeng Wang
- College of Biological Science and Technology, Fuzhou University, Fuzhou 350108, P.R. China
- National Engineering Laboratory for High-efficiency Enzyme Expression, Fuzhou 350002, P. R. China
| | - Xiaoyun Huang
- College of Biological Science and Technology, Fuzhou University, Fuzhou 350108, P.R. China
| | - Tzi Bun Ng
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, China
| | - Juan Lin
- College of Biological Science and Technology, Fuzhou University, Fuzhou 350108, P.R. China
- National Engineering Laboratory for High-efficiency Enzyme Expression, Fuzhou 350002, P. R. China
- * E-mail: (JL); (XYY)
| | - Xiu Yun Ye
- College of Biological Science and Technology, Fuzhou University, Fuzhou 350108, P.R. China
- National Engineering Laboratory for High-efficiency Enzyme Expression, Fuzhou 350002, P. R. China
- * E-mail: (JL); (XYY)
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Zhao L, Meng K, Shi P, Bai Y, Luo H, Huang H, Wang Y, Yang P, Yao B. A novel thermophilic xylanase from Achaetomium sp. Xz-8 with high catalytic efficiency and application potentials in the brewing and other industries. Process Biochem 2013. [DOI: 10.1016/j.procbio.2013.08.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Satyanarayana DVT. Improvement in thermostability of metagenomic GH11 endoxylanase (Mxyl) by site-directed mutagenesis and its applicability in paper pulp bleaching process. J Ind Microbiol Biotechnol 2013; 40:1373-81. [PMID: 24100791 DOI: 10.1007/s10295-013-1347-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2013] [Accepted: 09/12/2013] [Indexed: 11/28/2022]
Abstract
An attempt has been made for enhancing the thermostability of xylanase (Mxyl) retrieved from a compost-soil-based metagenomic library. The analysis of the structure of xylanase by molecular dynamics simulation revealed more structural fluctuations in β-sheets. When the surface of β-sheets was enriched with arginine residues by substituting serine/threonine by site-directed mutagenesis, the enzyme with four arginine substitutions (MxylM4) exhibited enhanced thermostability at 80 °C. The T 1/2 of MxylM4 at 80 °C, in the presence of birchwood xylan, increased from 130 to 150 min at 80 °C without any alteration in optimum pH and temperature and molecular mass. Improvement in thermostability of MxylM4 was corroborated by increase in T m by 6 °C over that of Mxyl. The K m of MxylM4, however, increased from 8.01 ± 0.56 of Mxyl to 12.5 ± 0.32 mg ml(-1), suggesting a decrease in the affinity as well as specific enzyme activity. The Mxyl as well as MxylM4 liberated chromophores and lignin-derived compounds from kraft pulp, indicating their applicability in pulp bleaching.
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Wu Q, Li Y, Li Y, Gao S, Wang M, Zhang T, Chen J. Identification of a novel fungus, Leptosphaerulina chartarum SJTU59 and characterization of its xylanolytic enzymes. PLoS One 2013; 8:e73729. [PMID: 24040044 PMCID: PMC3767624 DOI: 10.1371/journal.pone.0073729] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 07/20/2013] [Indexed: 11/19/2022] Open
Abstract
Xylanolytic enzymes are widely used in processing industries, e.g., pulp and paper, food, livestock feeds, and textile. Furthermore, certain xylanotic enzymes have demonstrated the capability to improve the resistance and immunity of plants. Screening of high-yield microbial xylanolytic enzyme producers is significant for improving large-scale cost-effective xylanolytic enzyme production. This study provided new evidence of high-level xylanolytic enzyme production by a novel fungus, designated Leptosphaerulina chartarum SJTU59. Under laboratory conditions, L. chartarum SJTU59 produced xylanolytic enzymes of up to 17.566 U/mL (i.e., 878.307 U/g substrate). The enzyme solution was relatively stable over a wide range of pH (pH 3.0 to pH 9.0) and temperature (40°C to 65°C) while showing high resistance to the majority of metal ions tested. Composition analysis of the hydrolytic products of xylan showed sufficient degradation by xylanolytic enzymes from L. chartarum SJTU59, mainly the monosaccharide xylose, and a small amount of xylobiose were enzymatically produced; whereas in the presence of sufficient xylan substrates, mainly xylooligosaccharides, an emerging prebiotic used in food industry, were produced. In addition, the xylanolytic enzyme preparation from L. chartarum SJTU59 could initiate tissue necrosis and oxidative burst in tobacco leaves, which may be related to enhanced plant defense to adversity and disease. L. chartarum SJTU59 possessed a complex xylanolytic enzyme system, from which two novel endo-β-1,4-xylanases of the glycoside hydrolase (GH) family 10, one novel endo-β-1,4-xylanase of the GH family 11, and one novel β-xylosidase of the GH family 43 were obtained via rapid amplification of complementary DNA ends. Given the high yield and stable properties of xylanolytic enzymes produced by L. chartarum SJTU59, future studies will be conducted to characterize the properties of individual xylanolytic enzymes from L. chartarum SJTU59. xylanolytic enzymes-encoding gene(s) of potential use for industrial and agricultural applications will be screened to construct genetically engineered strains.
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MESH Headings
- Amino Acid Sequence
- Ascomycota/enzymology
- Ascomycota/genetics
- Ascomycota/isolation & purification
- Base Sequence
- Biocatalysis/drug effects
- DNA, Complementary/chemistry
- DNA, Complementary/genetics
- DNA, Ribosomal/chemistry
- DNA, Ribosomal/classification
- DNA, Ribosomal/genetics
- DNA, Ribosomal Spacer/genetics
- Endo-1,4-beta Xylanases/classification
- Endo-1,4-beta Xylanases/genetics
- Endo-1,4-beta Xylanases/metabolism
- Enzyme Stability
- Fungal Proteins/genetics
- Fungal Proteins/metabolism
- Hydrogen-Ion Concentration
- Hydrolysis
- Isoenzymes/classification
- Isoenzymes/genetics
- Isoenzymes/metabolism
- Metals/pharmacology
- Molecular Sequence Data
- Phylogeny
- Plant Leaves/microbiology
- RNA, Ribosomal/genetics
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
- Sequence Homology, Nucleic Acid
- Temperature
- Nicotiana/microbiology
- Xylans/metabolism
- Xylose/metabolism
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Affiliation(s)
- Qiong Wu
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Yaqian Li
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Yingying Li
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Shigang Gao
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Meng Wang
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Tailong Zhang
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
| | - Jie Chen
- School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China
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22
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Alvarez TM, Goldbeck R, dos Santos CR, Paixão DAA, Gonçalves TA, Franco Cairo JPL, Almeida RF, de Oliveira Pereira I, Jackson G, Cota J, Büchli F, Citadini AP, Ruller R, Polo CC, de Oliveira Neto M, Murakami MT, Squina FM. Development and biotechnological application of a novel endoxylanase family GH10 identified from sugarcane soil metagenome. PLoS One 2013; 8:e70014. [PMID: 23922891 PMCID: PMC3726488 DOI: 10.1371/journal.pone.0070014] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Accepted: 06/13/2013] [Indexed: 01/26/2023] Open
Abstract
Metagenomics has been widely employed for discovery of new enzymes and pathways to conversion of lignocellulosic biomass to fuels and chemicals. In this context, the present study reports the isolation, recombinant expression, biochemical and structural characterization of a novel endoxylanase family GH10 (SCXyl) identified from sugarcane soil metagenome. The recombinant SCXyl was highly active against xylan from beechwood and showed optimal enzyme activity at pH 6,0 and 45°C. The crystal structure was solved at 2.75 Å resolution, revealing the classical (β/α)8-barrel fold with a conserved active-site pocket and an inherent flexibility of the Trp281-Arg291 loop that can adopt distinct conformational states depending on substrate binding. The capillary electrophoresis analysis of degradation products evidenced that the enzyme displays unusual capacity to degrade small xylooligosaccharides, such as xylotriose, which is consistent to the hydrophobic contacts at the +1 subsite and low-binding energies of subsites that are distant from the site of hydrolysis. The main reaction products from xylan polymers and phosphoric acid-pretreated sugarcane bagasse (PASB) were xylooligosaccharides, but, after a longer incubation time, xylobiose and xylose were also formed. Moreover, the use of SCXyl as pre-treatment step of PASB, prior to the addition of commercial cellulolytic cocktail, significantly enhanced the saccharification process. All these characteristics demonstrate the advantageous application of this enzyme in several biotechnological processes in food and feed industry and also in the enzymatic pretreatment of biomass for feedstock and ethanol production.
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Affiliation(s)
- Thabata M. Alvarez
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Campinas, São Paulo, Brasil
- Departamento de Bioquímica, Instituto de Biologia (IB), Universidade Estadual de Campinas (UNICAMP), Campinas, São Paulo, Brasil
| | - Rosana Goldbeck
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Campinas, São Paulo, Brasil
| | - Camila Ramos dos Santos
- Laboratório Nacional de Biociências (LNBio), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Campinas, São Paulo, Brasil
| | - Douglas A. A. Paixão
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Campinas, São Paulo, Brasil
| | - Thiago A. Gonçalves
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Campinas, São Paulo, Brasil
- Departamento de Bioquímica, Instituto de Biologia (IB), Universidade Estadual de Campinas (UNICAMP), Campinas, São Paulo, Brasil
| | - João Paulo L. Franco Cairo
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Campinas, São Paulo, Brasil
- Departamento de Bioquímica, Instituto de Biologia (IB), Universidade Estadual de Campinas (UNICAMP), Campinas, São Paulo, Brasil
| | - Rodrigo Ferreira Almeida
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Campinas, São Paulo, Brasil
| | - Isabela de Oliveira Pereira
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Campinas, São Paulo, Brasil
| | - George Jackson
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Campinas, São Paulo, Brasil
| | - Junio Cota
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Campinas, São Paulo, Brasil
| | - Fernanda Büchli
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Campinas, São Paulo, Brasil
- Departamento de Bioquímica, Instituto de Biologia (IB), Universidade Estadual de Campinas (UNICAMP), Campinas, São Paulo, Brasil
| | - Ana Paula Citadini
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Campinas, São Paulo, Brasil
| | - Roberto Ruller
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Campinas, São Paulo, Brasil
| | - Carla Cristina Polo
- Laboratório Nacional de Biociências (LNBio), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Campinas, São Paulo, Brasil
| | - Mario de Oliveira Neto
- Departamento de Física e Biofísica, Instituto de Biociências, Universidade Estadual Paulista (UNESP), Botucatu, São Paulo, Brasil
| | - Mário T. Murakami
- Laboratório Nacional de Biociências (LNBio), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Campinas, São Paulo, Brasil
- * E-mail: (FMS); (MTM)
| | - Fabio M. Squina
- Laboratório Nacional de Ciência e Tecnologia do Bioetanol (CTBE), Centro Nacional de Pesquisa em Energia e Materiais (CNPEM), Campinas, São Paulo, Brasil
- * E-mail: (FMS); (MTM)
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Zhao L, Meng K, Bai Y, Shi P, Huang H, Luo H, Wang Y, Yang P, Song W, Yao B. Two family 11 xylanases from Achaetomium sp. Xz-8 with high catalytic efficiency and application potentials in the brewing industry. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2013; 61:6880-6889. [PMID: 23790084 DOI: 10.1021/jf4001296] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
This study identified two family-11 xylanase genes (xynC81 and xynC83) in Achaetomium sp. Xz-8, a thermophilic strain from a desert area with substantial xylanase activity, and successfully expressed them in Pichia pastoris . Their deduced amino acid sequences showed the highest identity of ≤90% to known fungal xylanases and of ≤62% with each other. The purified recombinant xylanases showed optimal activities at pH 5.5 and 60-65 °C and exhibited stability over pH 5.0-10.0 and temperatures at 55 °C and below. XynC81 had high catalytic efficiency (6082 mL/s/mg), and XynC83 was favorable for xylooligosaccharide production. Under simulated mashing conditions, combination of XynC83 and a commercial β-glucanase improved the filtration rate by 34.76%, which is much better than that of Novozymes Ultraflo (20.71%). XynC81 and XynC83 had a synergistic effect on viscosity reduction (7.08%), which is comparable with that of Ultraflo (8.47%). Thus, XynC81 and XynC83 represent good candidates for application in the brewing industry.
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Affiliation(s)
- Liang Zhao
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing 100081, People's Republic of China
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24
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Cloning, expression and characteristics of a novel alkalistable and thermostable xylanase encoding gene (Mxyl) retrieved from compost-soil metagenome. PLoS One 2013; 8:e52459. [PMID: 23382818 PMCID: PMC3561394 DOI: 10.1371/journal.pone.0052459] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Accepted: 11/19/2012] [Indexed: 11/19/2022] Open
Abstract
Background The alkalistable and thermostable xylanases are in high demand for pulp bleaching in paper industry and generating xylooligosaccharides by hydrolyzing xylan component of agro-residues. The compost-soil samples, one of the hot environments, are expected to be a rich source of microbes with thermostable enzymes. Methodology/Principal Findings Metagenomic DNA from hot environmental samples could be a rich source of novel biocatalysts. While screening metagenomic library constructed from DNA extracted from the compost-soil in the p18GFP vector, a clone (TSDV-MX1) was detected that exhibited clear zone of xylan hydrolysis on RBB xylan plate. The sequencing of 6.321 kb DNA insert and its BLAST analysis detected the presence of xylanase gene that comprised 1077 bp. The deduced protein sequence (358 amino acids) displayed homology with glycosyl hydrolase (GH) family 11 xylanases. The gene was subcloned into pET28a vector and expressed in E. coli BL21 (DE3). The recombinant xylanase (rMxyl) exhibited activity over a broad range of pH and temperature with optima at pH 9.0 and 80°C. The recombinant xylanase is highly thermostable having T1/2 of 2 h at 80°C and 15 min at 90°C. Conclusion/Significance This is the first report on the retrieval of xylanase gene through metagenomic approach that encodes an enzyme with alkalistability and thermostability. The recombinant xylanase has a potential application in paper and pulp industry in pulp bleaching and generating xylooligosaccharides from the abundantly available agro-residues.
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25
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Gulvik CA, Effler TC, Wilhelm SW, Buchan A. De-MetaST-BLAST: a tool for the validation of degenerate primer sets and data mining of publicly available metagenomes. PLoS One 2012. [PMID: 23189198 PMCID: PMC3506598 DOI: 10.1371/journal.pone.0050362] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Development and use of primer sets to amplify nucleic acid sequences of interest is fundamental to studies spanning many life science disciplines. As such, the validation of primer sets is essential. Several computer programs have been created to aid in the initial selection of primer sequences that may or may not require multiple nucleotide combinations (i.e., degeneracies). Conversely, validation of primer specificity has remained largely unchanged for several decades, and there are currently few available programs that allows for an evaluation of primers containing degenerate nucleotide bases. To alleviate this gap, we developed the program De-MetaST that performs an in silico amplification using user defined nucleotide sequence dataset(s) and primer sequences that may contain degenerate bases. The program returns an output file that contains the in silico amplicons. When De-MetaST is paired with NCBI’s BLAST (De-MetaST-BLAST), the program also returns the top 10 nr NCBI database hits for each recovered in silico amplicon. While the original motivation for development of this search tool was degenerate primer validation using the wealth of nucleotide sequences available in environmental metagenome and metatranscriptome databases, this search tool has potential utility in many data mining applications.
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Affiliation(s)
- Christopher A. Gulvik
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, United States of America
| | - T. Chad Effler
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, United States of America
- Department of Electrical Engineering and Computer Science, University of Tennessee, Knoxville, Tennessee, United States of America
| | - Steven W. Wilhelm
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, United States of America
| | - Alison Buchan
- Department of Microbiology, University of Tennessee, Knoxville, Tennessee, United States of America
- * E-mail:
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26
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Verma D, Satyanarayana T. Molecular approaches for ameliorating microbial xylanases. BIORESOURCE TECHNOLOGY 2012; 117:360-367. [PMID: 22595098 DOI: 10.1016/j.biortech.2012.04.034] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2012] [Revised: 04/09/2012] [Accepted: 04/11/2012] [Indexed: 05/31/2023]
Abstract
In industrial processes, chemical catalysis is being replaced by enzyme catalysis, since the latter is environmentally benign, non-persistent and cost effective. Microbial xylanases have significant applications in textile, baking, food and feed industries, and in paper and pulp industries for reducing the chlorine requirement. The hazardous chlorine required for bleaching can be reduced up to 25-30% by including an enzymatic step in the pulp bleaching process. The paper pulp bleaching requires xylanases that are active at alkaline pH and elevated temperatures. The enzymes from the cultured microbes do not perform optimally in the paper industry due to their inadequate stability under the process conditions of high temperature and alkaline pH. This review, therefore, deals with the rationale of molecular approaches such as protein engineering for designing xylanases with improved characteristics to suit the process conditions in industries, and prospects and problems.
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Affiliation(s)
- Digvijay Verma
- Department of Microbiology, University of Delhi South Campus, New Delhi 110 021, India
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27
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Baek CU, Lee SG, Chung YR, Cho I, Kim JH. Cloning of a Family 11 Xylanase Gene from Bacillus amyloliquefaciens CH51 Isolated from Cheonggukjang. Indian J Microbiol 2012; 52:695-700. [PMID: 24293733 DOI: 10.1007/s12088-012-0260-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2012] [Accepted: 03/01/2012] [Indexed: 10/28/2022] Open
Abstract
Bacillus amyloliquefaciens CH51, an isolate from cheonggukjang, Korean fermented soyfood, secretes several enzymes into culture medium. A gene encoding 19 kDa xylanase was cloned by PCR. Sequencing showed that the gene encoded a glycohydrolase family 11 xylanase and named xynA. xynAHis, xynA with additional codons for his-tag, was overexpressed in Escherichia coli BL21(DE3) using pET-26b(+). XynAHis was purified using HisTrap affinity column. Km and Vmax of XynAHis were 0.363 mg/ml and 701.1 μmol/min/mg, respectively with birchwood xylan as a substrate. The optimum pH and temperature were pH 4 and 25 °C, respectively. When xynA was introduced into Bacillus subtilis WB600, active XynA was secreted into culture medium.
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Affiliation(s)
- C U Baek
- Division of Applied Life Science (Bk21), Graduate School, Research Institute of Life Sciences, Gyeongsang National University, Jinju, Korea
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28
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Soares FL, Melo IS, Dias ACF, Andreote FD. Cellulolytic bacteria from soils in harsh environments. World J Microbiol Biotechnol 2012; 28:2195-203. [DOI: 10.1007/s11274-012-1025-2] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Accepted: 02/05/2012] [Indexed: 10/28/2022]
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29
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Characterization of a thermostable and alkaline xylanase from Bacillus sp. and its bleaching impact on wheat straw pulp. World J Microbiol Biotechnol 2011; 28:513-22. [DOI: 10.1007/s11274-011-0842-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Accepted: 07/08/2011] [Indexed: 10/18/2022]
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30
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Van Gool MP, Vancsó I, Schols HA, Toth K, Szakacs G, Gruppen H. Screening for distinct xylan degrading enzymes in complex shake flask fermentation supernatants. BIORESOURCE TECHNOLOGY 2011; 102:6039-47. [PMID: 21440435 DOI: 10.1016/j.biortech.2011.02.105] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2010] [Revised: 02/15/2011] [Accepted: 02/27/2011] [Indexed: 05/02/2023]
Abstract
The efficient degradation of complex xylans needs collaboration of many xylan degrading enzymes. Assays for xylan degrading activities based on reducing sugars or PNP substrates are not indicative for the presence of enzymes able to degrade complex xylans: They do not provide insight into the possible presence of xylanase-accessory enzymes within enzyme mixtures. A new screening method is described, by which specific xylan modifying enzymes can be detected. Fermentation supernatants of 78 different fungal soil isolates grown on wheat straw were analyzed by HPLC and MS. This strategy is powerful in recognizing xylanases, arabinoxylan hydrolases, acetyl xylan esterases and glucuronidases. No fungus produced all enzymes necessary to totally degrade the substrates tested. Some fungi produce high levels of xylanase active against linear xylan, but are unable to degrade complex xylans. Other fungi producing relative low levels of xylanase secrete many useful accessory enzyme component(s).
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Affiliation(s)
- M P Van Gool
- Wageningen University, Laboratory of Food Chemistry, Bomenweg 2, 6703 HD Wageningen, The Netherlands
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31
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Zhao Y, Luo H, Meng K, Shi P, Wang G, Yang P, Yuan T, Yao B. A xylanase gene directly cloned from the genomic DNA of alkaline wastewater sludge showing application potential in the paper industry. Appl Biochem Biotechnol 2011; 165:35-46. [PMID: 21484273 DOI: 10.1007/s12010-011-9231-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Accepted: 03/21/2011] [Indexed: 11/25/2022]
Abstract
A xylanase gene, aws-2x, was directly cloned from the genomic DNA of the alkaline wastewater sludge using degenerated PCR and modified TAIL-PCR. The deduced amino acid sequence of AWS-2x shared the highest identity (60%) with the xylanase from Chryseobacterium gleum belonging to the glycosyl hydrolase GH family 10. Recombinant AWS-2x was expressed in Escherichia coli BL21 (DE3) and purified to electrophoretic homogeneity. The enzyme showed maximal activity at pH 7.5 and 55 °C, maintained more than 50% of maximal activity when assayed at pH 9.0, and was stable over a wide pH range from 4.0 to 11.0. The specific activity of AWS-2x towards hardwood xylan (beechwood and birchwood xylan) was significantly higher than that to cereal xylan (oat spelt xylan and wheat arabinoxylan). These properties make AWS-2x a potential candidate for application in the pulp and paper industry.
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Affiliation(s)
- Yanyu Zhao
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, No. 12 Zhongguancun South Street, Beijing, 100081, People's Republic of China.
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Wang G, Luo H, Meng K, Wang Y, Huang H, Shi P, Pan X, Yang P, Diao Q, Zhang H, Yao B. High genetic diversity and different distributions of glycosyl hydrolase family 10 and 11 xylanases in the goat rumen. PLoS One 2011; 6:e16731. [PMID: 21304822 PMCID: PMC3033422 DOI: 10.1371/journal.pone.0016731] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2010] [Accepted: 12/24/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The rumen harbors a complex microbial ecosystem for efficient hydrolysis of plant polysaccharides which are the main constituent of the diet. Xylanase is crucial for hemicellulose hydrolysis and plays an important role in the plant cell wall degradation. Xylanases of ruminal strains were widely studied, but few studies have focused on their diversity in rumen microenvironment. METHODOLOGY/PRINCIPAL FINDINGS We explored the genetic diversity of xylanases belonging to two major glycosyl hydrolase families (GH 10 and 11) in goat rumen contents by analyzing the amplicons generated with two degenerate primer sets. Fifty-two distinct GH 10 and 35 GH 11 xylanase gene fragments (similarity <95%) were retrieved, and most had low identities with known sequences. Based on phylogenetic analysis, all GH 10 xylanase sequences fell into seven clusters, and 88.5% of them were related to xylanases from Bacteroidetes. Five clusters of GH 11 xylanase sequences were identified. Of these, 85.7% were related to xylanases from Firmicutes, and 14.3% were related to those of rumen fungi. Two full-length xylanase genes (one for each family) were directly cloned and expressed in Escherichia coli. Both the recombinant enzymes showed substantial xylanase activity, and were purified and characterized. Combined with the results of sheep rumen, Bacteroidetes and Firmicutes are the two major phyla of xylan-degrading microorganisms in rumen, which is distinct from the representatives of other environments such as soil and termite hindgut, suggesting that xylan-degrading microorganisms are environment specific. CONCLUSION/SIGNIFICANCE The numerous new xylanase genes suggested the functional diversity of xylanase in the rumen microenvironment which may have great potential applications in industry and agriculture. The phylogenetic diversity and different distributions of xylanase genes will help us understand their roles in plant cell wall degradation in the rumen microenvironment.
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Affiliation(s)
- Guozeng Wang
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China
| | - Huiying Luo
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China
| | - Kun Meng
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China
| | - Yaru Wang
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China
| | - Huoqing Huang
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China
| | - Pengjun Shi
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China
| | - Xia Pan
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China
| | - Peilong Yang
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China
| | - Qiyu Diao
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China
| | - Hongfu Zhang
- State Key Lab of Animal Nutrition, Institute of Animal Science, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China
| | - Bin Yao
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China
- * E-mail:
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Wang G, Luo H, Wang Y, Huang H, Shi P, Yang P, Meng K, Bai Y, Yao B. A novel cold-active xylanase gene from the environmental DNA of goat rumen contents: direct cloning, expression and enzyme characterization. BIORESOURCE TECHNOLOGY 2011; 102:3330-3336. [PMID: 21106368 DOI: 10.1016/j.biortech.2010.11.004] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2010] [Revised: 10/28/2010] [Accepted: 11/01/2010] [Indexed: 05/30/2023]
Abstract
A xylanase-coding gene, xynGR40, was cloned directly from the environmental DNA of goat rumen contents and expressed in Escherichia coli BL21 (DE3). The 1446-bp full-length gene encodes a 481-residue polypeptide (XynGR40) containing a catalytic domain belonging to glycosyl hydrolase (GH) family 10. Phylogenetic analysis indicated that XynGR40 was closely related with microbial xylanases of gastrointestinal source. Purified recombinant XynGR40 exhibited high activity at low temperatures, and remained active (∼10% of the activity) even at 0°C. The optimal temperature of XynGR40 was 30°C, much lower than other xylanases from rumen. Compared with mesophilic and thermophilic counterparts, XynGR40 had fewer hydrogen bonds and salt bridges, and lengthened loops in the catalytic domain. The enzyme also had relatively better stability at mesophilic temperatures and a higher catalytic efficiency than other known GH 10 cold active xylanases. These properties suggest that XynGR40 is a novel cold active xylanase and has great potential for basic research and industrial applications.
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Affiliation(s)
- Guozeng Wang
- Key Laboratory for Feed Biotechnology of the Ministry of Agriculture, Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, People's Republic of China
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