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An H, Ching XH, Cheah WJ, Lim WL, Ee KY, Chong CS, Lam MQ. Genomic analysis of a halophilic bacterium Nesterenkonia sp. CL21 with ability to produce a diverse group of lignocellulolytic enzymes. Folia Microbiol (Praha) 2024:10.1007/s12223-024-01178-9. [PMID: 38842626 DOI: 10.1007/s12223-024-01178-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2023] [Accepted: 05/26/2024] [Indexed: 06/07/2024]
Abstract
Halophilic bacteria are extremophiles that thrive in saline environment. Their ability to withstand such harsh conditions makes them an ideal choice for industrial applications such as lignocellulosic biomass degradation. In this study, a halophilic bacterium with the ability to produce extracellular cellulases and hemicellulases, designated as Nesterenkonia sp. CL21, was isolated from mangrove sediment in Tanjung Piai National Park, Malaysia. Thus far, studies on lignocellulolytic enzymes concerning bacterial species under this genus are limited. To gain a comprehensive understanding of its lignocellulose-degrading potential, the whole genome was sequenced using the Illumina NovaSeq 6000 platform. The genome of strain CL21 was assembled into 25 contigs with 3,744,449 bp and a 69.74% GC content and was predicted to contain 3,348 coding genes. Based on taxonomy analysis, strain CL21 shares 73.8 to 82.0% average nucleotide identity with its neighbouring species, below the 95% threshold, indicating its possible status as a distinct species in Nesterenkonia genus. Through in-depth genomic mining, a total of 81 carbohydrate-active enzymes were encoded. Among these, 24 encoded genes were identified to encompass diverse cellulases (GH3), xylanases (GH10, GH11, GH43, GH51, GH127 and CE4), mannanases (GH38 and GH106) and pectinases (PL1, PL9, and PL11). The production of lignocellulolytic enzymes was tested in the presence of several substrates. This study revealed that strain CL21 can produce a diverse array of enzymes which are active at different time points. By combining experimental data with genomic information, the ability of strain CL21 to produce lignocellulolytic enzymes has been elucidated, with potential applications in biorefinery industry.
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Affiliation(s)
- Hongxuan An
- Department of Biological Science, Faculty of Science, Universiti Tunku Abdul Rahman, Jalan Universiti, Bandar Barat, 31900, Kampar, Perak, Malaysia
| | - Xin Huey Ching
- Department of Biosciences, Faculty of Science, Universiti Teknologi Malaysia, 81310, Skudai, Johor, Malaysia
| | - Wai Jun Cheah
- Department of Biosciences, Faculty of Science, Universiti Teknologi Malaysia, 81310, Skudai, Johor, Malaysia
| | - Wei Lun Lim
- Faculty of Chemical Engineering Technology, Universiti Malaysia Perlis (UniMAP), 02600, Arau, Perlis, Malaysia
| | - Kah Yaw Ee
- Department of Agricultural and Food Science, Faculty of Science, Universiti Tunku Abdul Rahman, Jalan Universiti, Bandar Barat, 31900, Kampar, Perak, Malaysia
- Centre for Agriculture and Food Research, Universiti Tunku Abdul Rahman, Jalan Universiti, Bandar Barat, 31900, Kampar, Perak, Malaysia
| | - Chun Shiong Chong
- Department of Biosciences, Faculty of Science, Universiti Teknologi Malaysia, 81310, Skudai, Johor, Malaysia.
| | - Ming Quan Lam
- Department of Biological Science, Faculty of Science, Universiti Tunku Abdul Rahman, Jalan Universiti, Bandar Barat, 31900, Kampar, Perak, Malaysia.
- Centre for Agriculture and Food Research, Universiti Tunku Abdul Rahman, Jalan Universiti, Bandar Barat, 31900, Kampar, Perak, Malaysia.
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Ben Hmad I, Gargouri A. Halophilic filamentous fungi and their enzymes: Potential biotechnological applications. J Biotechnol 2024; 381:11-18. [PMID: 38159888 DOI: 10.1016/j.jbiotec.2023.12.008] [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: 09/28/2023] [Revised: 12/12/2023] [Accepted: 12/15/2023] [Indexed: 01/03/2024]
Abstract
Recently, interest in the study of microorganisms growing under extreme conditions, particularly halophiles, has increased due to their potential use in industrial processes. Halophiles are the class of microorganisms that grow optimally at high NaCl concentrations and are capable of producing halophilic enzymes capable of catalyzing reactions under harsh conditions. So far, fungi are the least studied halophilic microorganisms, even though they have been shown to counteract these extreme conditions by producing secondary metabolites with very interesting properties. This review highlights mechanisms that allow halophilic fungi to adapt high salinity and the specificity of their enzymes to a spectrum of action in industrial and environmental applications. The peculiarities of these enzymes justify the urgent need to apply green alternative compounds in industries.
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Affiliation(s)
- Ines Ben Hmad
- Laboratory of Molecular Biology of Eukaryotes, Centre of Biotechnology of Sfax (CBS), University of Sfax, B.P "1177", Sfax 3018, Tunisia.
| | - Ali Gargouri
- Laboratory of Molecular Biology of Eukaryotes, Centre of Biotechnology of Sfax (CBS), University of Sfax, B.P "1177", Sfax 3018, Tunisia
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Ariaeenejad S, Gharechahi J, Foroozandeh Shahraki M, Fallah Atanaki F, Han JL, Ding XZ, Hildebrand F, Bahram M, Kavousi K, Hosseini Salekdeh G. Precision enzyme discovery through targeted mining of metagenomic data. NATURAL PRODUCTS AND BIOPROSPECTING 2024; 14:7. [PMID: 38200389 PMCID: PMC10781932 DOI: 10.1007/s13659-023-00426-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2023] [Accepted: 12/19/2023] [Indexed: 01/12/2024]
Abstract
Metagenomics has opened new avenues for exploring the genetic potential of uncultured microorganisms, which may serve as promising sources of enzymes and natural products for industrial applications. Identifying enzymes with improved catalytic properties from the vast amount of available metagenomic data poses a significant challenge that demands the development of novel computational and functional screening tools. The catalytic properties of all enzymes are primarily dictated by their structures, which are predominantly determined by their amino acid sequences. However, this aspect has not been fully considered in the enzyme bioprospecting processes. With the accumulating number of available enzyme sequences and the increasing demand for discovering novel biocatalysts, structural and functional modeling can be employed to identify potential enzymes with novel catalytic properties. Recent efforts to discover new polysaccharide-degrading enzymes from rumen metagenome data using homology-based searches and machine learning-based models have shown significant promise. Here, we will explore various computational approaches that can be employed to screen and shortlist metagenome-derived enzymes as potential biocatalyst candidates, in conjunction with the wet lab analytical methods traditionally used for enzyme characterization.
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Affiliation(s)
- Shohreh Ariaeenejad
- Department of Systems and Synthetic Biology, Agricultural Biotechnology Research Institute of Iran (ABRII), Agricultural Research Education and Extension Organization (AREEO), Karaj, Iran
| | - Javad Gharechahi
- Human Genetics Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Mehdi Foroozandeh Shahraki
- Laboratory of Complex Biological Systems and Bioinformatics (CBB), Institute of Biochemistry and Biophysics (IBB), University of Tehran, Tehran, Iran
| | - Fereshteh Fallah Atanaki
- Laboratory of Complex Biological Systems and Bioinformatics (CBB), Institute of Biochemistry and Biophysics (IBB), University of Tehran, Tehran, Iran
| | - Jian-Lin Han
- Livestock Genetics Program, International Livestock Research, Institute (ILRI), Nairobi, 00100, Kenya
- CAAS-ILRI Joint Laboratory On Livestock and Forage Genetic Resources, Institute of Animal Science, Chinese Academy of Agricultural Sciences (CAAS), Beijing, 100193, China
| | - Xue-Zhi Ding
- Key Laboratory of Yak Breeding Engineering, Lanzhou Institute of Husbandry and Pharmaceutical Sciences, Chinese Academy of Agricultural Sciences (CAAS), Lanzhou, 730050, China
| | - Falk Hildebrand
- Gut Microbes and Health, Quadram Institute Bioscience, Norwich, Norfolk, UK
- Digital Biology, Earlham Institute, Norwich, Norfolk, UK
| | - Mohammad Bahram
- Department of Ecology, Swedish University of Agricultural Sciences, Ulls Väg 16, 756 51, Uppsala, Sweden
- Department of Botany, Institute of Ecology and Earth Sciences, University of Tartu, 40 Lai St, Tartu, Estonia
| | - Kaveh Kavousi
- Laboratory of Complex Biological Systems and Bioinformatics (CBB), Institute of Biochemistry and Biophysics (IBB), University of Tehran, Tehran, Iran.
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Yin YR, Li XW, Long CH, Li L, Hang YY, Rao MD, Yan X, Liu QL, Sang P, Li WJ, Yang LQ. Characterization of a GH10 extremely thermophilic xylanase from the metagenome of hot spring for prebiotic production. Sci Rep 2023; 13:16053. [PMID: 37749183 PMCID: PMC10520001 DOI: 10.1038/s41598-023-42920-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2023] [Accepted: 09/16/2023] [Indexed: 09/27/2023] Open
Abstract
A xylanase gene (named xyngmqa) was identified from the metagenomic data of the Gumingquan hot spring (92.5 °C, pH 9.2) in Tengchong City, Yunnan Province, southwest China. It showed the highest amino acid sequence identity (82.70%) to endo-1,4-beta-xylanase from Thermotoga caldifontis. A constitutive expression plasmid (denominated pSHY211) and double-layer plate (DLP) method were constructed for cloning, expression, and identification of the XynGMQA gene. The XynGMQA gene was synthesized and successfully expressed in Escherichia coli DH5α. XynGMQA exhibited optimal activity at 90 °C and pH 4.6, being thermostable by maintaining 100% of its activity after 2 h incubated at 80 °C. Interestingly, its enzyme activity was enhanced by high temperatures (70 and 80 °C) and low pH (3.0-6.0). About 150% enzyme activity was detected after incubation at 70 °C for 20 to 60 min or 80 °C for 10 to 40 min, and more than 140% enzyme activity after incubation at pH 3.0 to 6.0 for 12 h. Hydrolytic products of beechwood xylan with XynGMQA were xylooligosaccharides, including xylobiose (X2), xylotriose (X3), and xylotetraose (X4). These properties suggest that XynGMQA as an extremely thermophilic xylanase, may be exploited for biofuel and prebiotic production from lignocellulosic biomass.
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Affiliation(s)
- Yi-Rui Yin
- College of Agriculture and Biological Science, Dali University, Dali, 671003, People's Republic of China.
| | - Xin-Wei Li
- College of Agriculture and Biological Science, Dali University, Dali, 671003, People's Republic of China
- Key Laboratory of Bioinformatics and Computational Biology, Department of Education of Yunnan Province, Dali University, Dali, 671003, People's Republic of China
| | - Chao-Hua Long
- College of Agriculture and Biological Science, Dali University, Dali, 671003, People's Republic of China
| | - Lei Li
- College of Agriculture and Biological Science, Dali University, Dali, 671003, People's Republic of China
| | - Yu-Ying Hang
- College of Agriculture and Biological Science, Dali University, Dali, 671003, People's Republic of China
| | - Meng-Di Rao
- College of Agriculture and Biological Science, Dali University, Dali, 671003, People's Republic of China
| | - Xin Yan
- College of Agriculture and Biological Science, Dali University, Dali, 671003, People's Republic of China
| | - Quan-Lin Liu
- College of Agriculture and Biological Science, Dali University, Dali, 671003, People's Republic of China
| | - Peng Sang
- College of Agriculture and Biological Science, Dali University, Dali, 671003, People's Republic of China
- Key Laboratory of Bioinformatics and Computational Biology, Department of Education of Yunnan Province, Dali University, Dali, 671003, People's Republic of China
| | - Wen-Jun Li
- College of Agriculture and Biological Science, Dali University, Dali, 671003, People's Republic of China.
- State Key Laboratory of Biocontrol, Guangdong Provincial Key Laboratory of Plant Resources and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, People's Republic of China.
| | - Li-Quan Yang
- College of Agriculture and Biological Science, Dali University, Dali, 671003, People's Republic of China.
- Key Laboratory of Bioinformatics and Computational Biology, Department of Education of Yunnan Province, Dali University, Dali, 671003, People's Republic of China.
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La Cono V, Messina E, Reva O, Smedile F, La Spada G, Crisafi F, Marturano L, Miguez N, Ferrer M, Selivanova EA, Golyshina OV, Golyshin PN, Rohde M, Krupovic M, Merkel AY, Sorokin DY, Hallsworth JE, Yakimov MM. Nanohaloarchaea as beneficiaries of xylan degradation by haloarchaea. Microb Biotechnol 2023; 16:1803-1822. [PMID: 37317055 PMCID: PMC10443357 DOI: 10.1111/1751-7915.14272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 04/18/2023] [Accepted: 04/28/2023] [Indexed: 06/16/2023] Open
Abstract
Climate change, desertification, salinisation of soils and the changing hydrology of the Earth are creating or modifying microbial habitats at all scales including the oceans, saline groundwaters and brine lakes. In environments that are saline or hypersaline, the biodegradation of recalcitrant plant and animal polysaccharides can be inhibited by salt-induced microbial stress and/or by limitation of the metabolic capabilities of halophilic microbes. We recently demonstrated that the chitinolytic haloarchaeon Halomicrobium can serve as the host for an ectosymbiont, nanohaloarchaeon 'Candidatus Nanohalobium constans'. Here, we consider whether nanohaloarchaea can benefit from the haloarchaea-mediated degradation of xylan, a major hemicellulose component of wood. Using samples of natural evaporitic brines and anthropogenic solar salterns, we describe genome-inferred trophic relations in two extremely halophilic xylan-degrading three-member consortia. We succeeded in genome assembly and closure for all members of both xylan-degrading cultures and elucidated the respective food chains within these consortia. We provide evidence that ectosymbiontic nanohaloarchaea is an active ecophysiological component of extremely halophilic xylan-degrading communities (although by proxy) in hypersaline environments. In each consortium, nanohaloarchaea occur as ectosymbionts of Haloferax, which in turn act as scavenger of oligosaccharides produced by xylan-hydrolysing Halorhabdus. We further obtained and characterised the nanohaloarchaea-host associations using microscopy, multi-omics and cultivation approaches. The current study also doubled culturable nanohaloarchaeal symbionts and demonstrated that these enigmatic nano-sized archaea can be readily isolated in binary co-cultures using an appropriate enrichment strategy. We discuss the implications of xylan degradation by halophiles in biotechnology and for the United Nation's Sustainable Development Goals.
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Affiliation(s)
| | | | - Oleg Reva
- Department of Biochemistry, Genetics and Microbiology, Faculty of Natural and Agricultural Sciences, Centre for Bioinformatics and Computational BiologyUniversity of PretoriaPretoriaSouth Africa
| | | | | | | | | | - Noa Miguez
- Instituto de Catalisis y Petroleoquimica (ICP), CSICMadridSpain
| | - Manuel Ferrer
- Instituto de Catalisis y Petroleoquimica (ICP), CSICMadridSpain
| | - Elena A. Selivanova
- Institute for Cellular and Intracellular SymbiosisUral Branch, Russian Academy of SciencesOrenburgRussia
| | | | | | - Manfred Rohde
- Central Facility for MicrobiologyHelmholtz Centre for Infection ResearchBraunschweigGermany
| | - Mart Krupovic
- Institut PasteurUniversité Paris Cité, Archaeal Virology UnitParisFrance
| | - Alexander Y. Merkel
- Winogradsky Institute of MicrobiologyResearch Centre of Biotechnology, Russian Academy of SciencesMoscowRussia
| | - Dimitry Y. Sorokin
- Winogradsky Institute of MicrobiologyResearch Centre of Biotechnology, Russian Academy of SciencesMoscowRussia
- Department of BiotechnologyDelft University of TechnologyDelftThe Netherlands
| | - John E. Hallsworth
- Institute for Global Food Security, School of Biological SciencesQueen's University BelfastNorthern IrelandUK
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Gharechahi J, Vahidi MF, Sharifi G, Ariaeenejad S, Ding XZ, Han JL, Salekdeh GH. Lignocellulose degradation by rumen bacterial communities: New insights from metagenome analyses. ENVIRONMENTAL RESEARCH 2023; 229:115925. [PMID: 37086884 DOI: 10.1016/j.envres.2023.115925] [Citation(s) in RCA: 23] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 03/26/2023] [Accepted: 04/15/2023] [Indexed: 05/03/2023]
Abstract
Ruminant animals house a dense and diverse community of microorganisms in their rumen, an enlarged compartment in their stomach, which provides a supportive environment for the storage and microbial fermentation of ingested feeds dominated by plant materials. The rumen microbiota has acquired diverse and functionally overlapped enzymes for the degradation of plant cell wall polysaccharides. In rumen Bacteroidetes, enzymes involved in degradation are clustered into polysaccharide utilization loci to facilitate coordinated expression when target polysaccharides are available. Firmicutes use free enzymes and cellulosomes to degrade the polysaccharides. Fibrobacters either aggregate lignocellulose-degrading enzymes on their cell surface or release them into the extracellular medium in membrane vesicles, a mechanism that has proven extremely effective in the breakdown of recalcitrant cellulose. Based on current metagenomic analyses, rumen Bacteroidetes and Firmicutes are categorized as generalist microbes that can degrade a wide range of polysaccharides, while other members adapted toward specific polysaccharides. Particularly, there is ample evidence that Verrucomicrobia and Spirochaetes have evolved enzyme systems for the breakdown of complex polysaccharides such as xyloglucans, peptidoglycans, and pectin. It is concluded that diversity in degradation mechanisms is required to ensure that every component in feeds is efficiently degraded, which is key to harvesting maximum energy by host animals.
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Affiliation(s)
- Javad Gharechahi
- Human Genetics Research Center, Baqiyatallah University of Medical Sciences, Tehran, Iran
| | - Mohammad Farhad Vahidi
- Animal Science Research Department, Qom Agricultural and Natural Resources Research and Education Center, Agricultural Research, Education and Extension Organization (AREEO), Qom, Iran
| | - Golandam Sharifi
- Department of Basic Sciences, Encyclopedia Research Center, Institute for Humanities and Cultural Studies, Tehran, Iran
| | - Shohreh Ariaeenejad
- Department of Systems Biology, Agricultural Biotechnology Research Institute of Iran, Agricultural Research, Education, And Extension Organization, Karaj, Iran
| | - Xue-Zhi Ding
- Key Laboratory of Yak Breeding Engineering, Lanzhou Institute of Husbandry and Pharmaceutical Sciences, Chinese Academy of Agricultural Sciences (CAAS), Lanzhou, 730050, China
| | - Jian-Lin Han
- Livestock Genetics Program, International Livestock Research, Institute (ILRI), 00100, Nairobi, Kenya; CAAS-ILRI Joint Laboratory on Livestock and Forage Genetic Resources, Institute of Animal Science, Chinese Academy of Agricultural Sciences (CAAS), Beijing, 100193, China.
| | - Ghasem Hosseini Salekdeh
- Department of Systems Biology, Agricultural Biotechnology Research Institute of Iran, Agricultural Research, Education, And Extension Organization, Karaj, Iran; School of Natural Sciences, Macquarie University, North Ryde, NSW, Australia.
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Meng Z, Yang C, Leng J, Zhu W, Cheng Y. Production, purification, characterization and application of two novel endoglucanases from buffalo rumen metagenome. J Anim Sci Biotechnol 2023; 14:16. [PMID: 36740711 PMCID: PMC9900955 DOI: 10.1186/s40104-022-00814-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2022] [Accepted: 12/02/2022] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Lignocellulose biomass is the most abundant and renewable material in nature. The objectives of this study were to characterize two endoglucanases TrepCel3 and TrepCel4, and determine the effect of the combination of them (1.2 mg TrepCel3, 0.8 mg TrepCel4) on in vitro rumen fermentation characteristics. In this study, three nature lignocellulosic substrates (rice straw, RS; wheat straw, WS; leymus chinensis, LC) were evaluated for their in vitro digestibility, gas, NH3-N and volatile fatty acid (VFA) production, and microbial protein (MCP) synthesis by adding enzymatic combination. METHODS Two endoglucanases' genes were successfully expressed in Escherichia coli (E. coli) BL21 (DE3), and enzymatic characteristics were further characterized. The combination of TrepCel3 and TrepCel4 was incubated with lignocellulosic substrates to evaluate its hydrolysis ability. RESULTS The maximum enzymatic activity of TrepCel3 was determined at pH 5.0 and 40 °C, while TrepCel4 was at pH 6.0 and 50 °C. They were stable over the temperature range of 30 to 60 °C, and active within the pH range of 4.0 to 9.0. The TrepCel3 and TrepCel4 had the highest activity in lichenan 436.9 ± 8.30 and 377.6 ± 6.80 U/mg, respectively. The combination of TrepCel3 and TrepCel4 exhibited the highest efficiency at the ratio of 60:40. Compared to maximum hydrolysis of TrepCel3 or TrepCel4 separately, this combination was shown to have a superior ability to maximize the saccharification yield from lignocellulosic substrates up to 188.4% for RS, 236.7% for wheat straw WS, 222.4% for LC and 131.1% for sugar beet pulp (SBP). Supplemental this combination enhanced the dry matter digestion (DMD), gas, NH3-N and VFA production, and MCP synthesis during in vitro rumen fermentation. CONCLUSIONS The TrepCel3 and TrepCel4 exhibited the synergistic relationship (60:40) and significantly increased the saccharification yield of lignocellulosic substrates. The combination of them stimulated in vitro rumen fermentation of lignocellulosic substrates. This combination has the potential to be a feed additive to improve agricultural residues utilization in ruminants. If possible, in the future, experiments in vivo should be carried out to fully evaluate its effect.
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Affiliation(s)
- Zhenxiang Meng
- Laboratory of Gastrointestinal Microbiology, National Center for International Research On Animal Gut Nutrition, Nanjing Agricultural University, Nanjing, 210095, China
| | - Chengjian Yang
- Buffalo Research Institute, Chinese Academy of Agricultural, Nanning, 530000, China
| | - Jing Leng
- Key Laboratory of Animal Nutrition and Feed Science of Yunnan Province, Yunnan Agricultural University, Kunming, 650000, China
| | - Weiyun Zhu
- Laboratory of Gastrointestinal Microbiology, National Center for International Research On Animal Gut Nutrition, Nanjing Agricultural University, Nanjing, 210095, China
| | - Yanfen Cheng
- Laboratory of Gastrointestinal Microbiology, National Center for International Research On Animal Gut Nutrition, Nanjing Agricultural University, Nanjing, 210095, China.
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Characterization of a novel bifunctional enzyme from buffalo rumen metagenome and its effect on in vitro ruminal fermentation and microbial community composition. ANIMAL NUTRITION 2023; 13:137-149. [PMID: 37123618 PMCID: PMC10130076 DOI: 10.1016/j.aninu.2023.01.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 12/26/2022] [Accepted: 01/09/2023] [Indexed: 01/15/2023]
Abstract
To efficiently use lignocellulosic materials in ruminants, it is crucial to explore effective enzymes, especially bifunctional enzymes. In this study, a novel stable bifunctional cellulase-xylanase protein from buffalo rumen metagenome was expressed and characterized, CelXyn2. The enzyme displayed optimal activity at pH 6.0 and 45 °C. The residual endoglucanase and xylanase activities were 90.6% and 86.4% after a 60-min pre-incubation at 55 °C. Hydrolysis of rice straw, wheat straw, sheepgrass and sugar beet pulp by CelXyn2 showed its ability to degrade both cellulose and hemicellulose polymers. Treatment with CelXyn2 improved the hydrolysis of agricultural residues with an evident increase in production of total gas, lactate and volatile fatty acids. The results of 16S rRNA and real-time PCR showed that the effect on in vitro ruminal microbial community depended on fermentation substrates. This study demonstrated that CelXyn2 could strengthen lignocellulose hydrolysis and in vitro ruminal fermentation. These characteristics of CelXyn2 distinguish it as a promising candidate for agricultural application.
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Zhu L, Liu LWC, Li Y, Pan K, Ouyang K, Song X, Xiong X, Qu M, Zhao X. Characteristics of recombinant xylanase from camel rumen metagenome and its effects on wheat bran hydrolysis. Int J Biol Macromol 2022; 220:1309-1317. [PMID: 36027987 DOI: 10.1016/j.ijbiomac.2022.08.146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 08/08/2022] [Accepted: 08/22/2022] [Indexed: 11/16/2022]
Abstract
In the present study, we explored the effects of a novel xylanase from camel rumen metagenome (CrXyn) on wheat bran hydrolysis. CrXyn was heterologously expressed in Escherichia coli and showed maximum activity at 40 °C and pH 7.0. Furthermore, CrXyn exhibited preferential hydrolysis of xylan, but no obvious activity toward other substrates, including carboxymethylcellulose and Avicel. Using wheat straw xylan as a substrate, the Km and Vmax values for CrXyn were 5.98 g/L and 179.9 μmol xylose/min/mg protein, respectively. Mn2+ was a strong accelerator and significantly enhanced CrXyn activity. However, CrXyn activity was inhibited (~50 %) by 1 mM and 5 mM ethylenediaminetetraacetic acid (EDTA) and completely inactivated by 5 mM Cu2+. CrXyn tolerated 5 mM sodium dodecyl sulphate (SDS) and 15 % methanol, ethanol, and dimethyl sulfoxide (DMSO), with >50 % residual activity. CrXyn effectively hydrolyzed wheat bran, with xylobiose and xylotetraose accounting for 79.1 % of total sugars produced. A remarkable synergistic effect was found between CrXyn and protease, leading to an obvious increase in amino acids released from wheat bran compared with the control. CrXyn also enhanced the in vitro hydrolysis of wheat bran. Thus, CrXyn exhibits great potential as a feed additive to improve the utilization of wheat bran in monogastric animal production.
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Affiliation(s)
- Linli Zhu
- Jiangxi Province Key Laboratory of Animal Nutrition/Engineering Research Center of Feed Development, Jiangxi Agricultural University, Nanchang, Jiangxi 330045, China
| | - Lei Wang Chanjuan Liu
- Jiangxi Province Key Laboratory of Animal Nutrition/Engineering Research Center of Feed Development, Jiangxi Agricultural University, Nanchang, Jiangxi 330045, China
| | - Yanjiao Li
- Jiangxi Province Key Laboratory of Animal Nutrition/Engineering Research Center of Feed Development, Jiangxi Agricultural University, Nanchang, Jiangxi 330045, China
| | - Ke Pan
- Jiangxi Province Key Laboratory of Animal Nutrition/Engineering Research Center of Feed Development, Jiangxi Agricultural University, Nanchang, Jiangxi 330045, China
| | - Kehui Ouyang
- Jiangxi Province Key Laboratory of Animal Nutrition/Engineering Research Center of Feed Development, Jiangxi Agricultural University, Nanchang, Jiangxi 330045, China
| | - Xiaozhen Song
- Jiangxi Province Key Laboratory of Animal Nutrition/Engineering Research Center of Feed Development, Jiangxi Agricultural University, Nanchang, Jiangxi 330045, China
| | - Xiaowen Xiong
- Jiangxi Province Key Laboratory of Animal Nutrition/Engineering Research Center of Feed Development, Jiangxi Agricultural University, Nanchang, Jiangxi 330045, China
| | - Mingren Qu
- Jiangxi Province Key Laboratory of Animal Nutrition/Engineering Research Center of Feed Development, Jiangxi Agricultural University, Nanchang, Jiangxi 330045, China
| | - Xianghui Zhao
- Jiangxi Province Key Laboratory of Animal Nutrition/Engineering Research Center of Feed Development, Jiangxi Agricultural University, Nanchang, Jiangxi 330045, China.
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Rajabi M, Nourisanami F, Ghadikolaei KK, Changizian M, Noghabi KA, Zahiri HS. Metagenomic psychrohalophilic xylanase from camel rumen investigated for bioethanol production from wheat bran using Bacillus subtilis AP. Sci Rep 2022; 12:8152. [PMID: 35581279 PMCID: PMC9114127 DOI: 10.1038/s41598-022-11412-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2021] [Accepted: 04/25/2022] [Indexed: 11/09/2022] Open
Abstract
Bioethanol produced from lignocellulosic biomass is regarded as a clean and sustainable energy source. The recalcitrant structure of lignocellulose is a major drawback to affordable bioethanol production from plant biomass. In this study, a novel endo-1,4-xylanase, named Xyn-2, from the camel rumen metagenome, was characterized and evaluated for hydrolysis of agricultural wastes. The enzyme was identified as a psychrohalophilic xylanase with maximum activity at 20 °C, keeping 58% of the activity at 0 °C, and exhibiting twice as much activity in 0.5–4 M NaCl concentrations. Xyn-2 was able to hydrolyze wheat bran (100%), sunflower-seed shell (70%), wheat straw (56%), rice straw (56%), and rice bran (41%), in the relative order of efficiency. Besides, the ethanologenic B. subtilis AP was evaluated without and with Xyn-2 for bioethanol production from wheat bran. The strain was able to produce 5.5 g/L ethanol with a yield of 22.6% in consolidated bioprocessing (CBP). The contribution of Xyn-2 to ethanol production of B. subtilis AP was studied in an SSF system (simultaneous saccharification and fermentation) giving rise to a significant increase in ethanol production (p ≤ 0.001) to a final concentration of 7.3 g/L with a yield of 26.8%. The results revealed that the camel rumen metagenome might be an invaluable source of novel xylanolytic enzymes with potential application in lignocellulosic biomass valorization. At the same time, the results suggest that B. subtilis with a diverse carbon-source preference and sophisticated systems for production and secretion of enzymes might be a promising candidate for strain development for bioethanol production from plant biomass. It might be assumed that the fortification of B. subtilis enzymatic arsenal with select xylanolytic enzymes from camel rumen metagenome may have a great impact on bioethanol production.
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Affiliation(s)
- Marzieh Rajabi
- Department of Energy and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran
| | - Farahdokht Nourisanami
- Department of Energy and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran
| | - Kamran Khalili Ghadikolaei
- Department of Energy and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran
| | - Mohammad Changizian
- Department of Energy and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran
| | - Kambiz Akbari Noghabi
- Department of Energy and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran
| | - Hossein Shahbani Zahiri
- Department of Energy and Environmental Biotechnology, National Institute of Genetic Engineering and Biotechnology (NIGEB), Tehran, Iran.
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11
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You S, Zhang YX, Shi F, Zhang WX, Li J, Zhang S, Chen ZL, Zhao WG, Wang J. Lowering energy consumption for fermentable sugar production from Ramulus mori: Engineered xylanase synergy and improved pretreatment strategy. BIORESOURCE TECHNOLOGY 2022; 344:126368. [PMID: 34808317 DOI: 10.1016/j.biortech.2021.126368] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 11/12/2021] [Accepted: 11/13/2021] [Indexed: 06/13/2023]
Abstract
Biorefinery of Ramulus mori with lower energy consumption through improved enzyme and pretreatment strategies was reported. Directed evolution and saturation mutagenesis were used for the modification of xylanase, the yield of fermentable sugars and the degree of synergy (DS) were determined for different pretreatment (seawater/non-seawater) and enzyme treatment groups (xylanase/cellulase/co-treatment). The dominant mutant I133A/Q143Y of Bispora sp. xylanase XYL10C_ΔN was obtained with improved specific activity (1860 U/mg), catalytic efficiency (1150 mL/s∙mg) at 40 °C, and thermostability (T50 increased by 7 °C). With the pretreatment of seawater immersion, the highest yield of fermentable sugars for Ramulus mori at 40 °C reached 199 μmol/g when hydrolyzed with cellulase and I133A/Q143Y, with the highest DS of 2.6; this was 4.5-fold that of the group hydrolyzed by cellulase alone with non-seawater pretreatment. Thus, bioconversion of reducing sugar from Ramulus mori was improved significantly at lower temperatures, which provides an efficient and energy-saving wayfor biofuel production.
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Affiliation(s)
- Shuai You
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212100, PR China; Key Laboratory of Silkworm and Mulberry Gene tic Improvement, Ministry of Agriculture and Rural Affairs, Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang, Jiangsu 212100, PR China
| | - Yi-Xin Zhang
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212100, PR China
| | - Fan Shi
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212100, PR China
| | - Wen-Xin Zhang
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212100, PR China
| | - Jing Li
- Department of Nephrology, Affiliated Hospital of Jiangsu University, Zhenjiang 212001, PR China
| | - Sheng Zhang
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212100, PR China
| | - Zhong-Li Chen
- Xinyuan Cocoon Silk Group Co., Ltd., Nantong 226600, PR China
| | - Wei-Guo Zhao
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212100, PR China; Key Laboratory of Silkworm and Mulberry Gene tic Improvement, Ministry of Agriculture and Rural Affairs, Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang, Jiangsu 212100, PR China
| | - Jun Wang
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu 212100, PR China; Key Laboratory of Silkworm and Mulberry Gene tic Improvement, Ministry of Agriculture and Rural Affairs, Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang, Jiangsu 212100, PR China.
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12
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Understanding the Role of Prevotella Genus in the Digestion of Lignocellulose and Other Substrates in Vietnamese Native Goats' Rumen by Metagenomic Deep Sequencing. Animals (Basel) 2021; 11:ani11113257. [PMID: 34827987 PMCID: PMC8614338 DOI: 10.3390/ani11113257] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 11/03/2021] [Accepted: 11/12/2021] [Indexed: 12/03/2022] Open
Abstract
Simple Summary Prevotella is an abundant genus which plays an important role for lignocellulose digestion in goat rumen and is significant to the yield and quality of milk and meat in cows. In a previous study, we sequenced bacterial metagenome from Vietnamese native goat rumen to get 8.4 GB clean data and found very diverse genes related to lignocellulose degradation. However, due to the limitation in the metagenomic size, low amount of complete lignocellulase genes, and high bacterial diversity, further analysis was restricted. In this study, metagenomic deep sequencing was used to obtain 48.66 GB of reliable data, thus some lignocellulolytic enzymes were first seen and a picture of bacterial enzymes involved in lignocellulose digestion in the goat rumen was drawn. The loci for galactan-, xylan-, and arabinan-processing in Prevotella were observed for the first time. We confirm that Prevotella plays pivotal role for hemicellulose digestion and significantly participates in starch, cellulose, hemicellulose, and pectin conversion in the goat rumen. A gene coding endoxylanase was expressed in E. coli. The recombinant enzyme was tolerant with some salts, detergents, and had high activity, thus is a good candidate for lignocellulose processing and as an animal feed food additive to effectively improve xylooligosaccharide production. Abstract Bacteria in rumen play pivotal roles in the digestion of nutrients to support energy for the host. In this study, metagenomic deep sequencing of bacterial metagenome extracted from the goats’ rumen generated 48.66 GB of data with 3,411,867 contigs and 5,367,270 genes. The genes were mainly functionally annotated by Kyoto Encyclopedia of Genes and Genomes (KEGG) Carbohydrate-Active enZYmes (CAZy), and HMMER database, and taxonomically classified by MEGAN. As a result, 65,554 genes encoding for 30 enzymes/proteins related to lignocellulose conversion were exploited, in which nine enzymes were seen for the first time in goat rumen. Prevotella was the most abundant genus, contributing 30% hemicellulases and 36% enzymes/proteins for lignocellulose pretreatment, and supporting 98.8% of feruloyl esterases and 71.7% acetylxylan esterases. In addition, 18 of the 22 most lignocellulose digesting- potential contigs belonged to Prevotella. Besides, Prevotella possessed many genes coding for amylolytic enzymes. One gene encoding for endoxylanase was successfully expressed in E. coli. The recombinant enzyme had high Vmax, was tolerant to some salts and detergents, worked better at pH 5.5–6.5, temperature 40–50 °C, and was capable to be used in practices. Based on these findings, we confirm that Prevotella plays a pivotal role for hemicellulose digestion and significantly participates in starch, cellulose, hemicellulose, and pectin digestion in the goat rumen.
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Verma D. Extremophilic Prokaryotic Endoxylanases: Diversity, Applicability, and Molecular Insights. Front Microbiol 2021; 12:728475. [PMID: 34566933 PMCID: PMC8458939 DOI: 10.3389/fmicb.2021.728475] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 08/06/2021] [Indexed: 11/13/2022] Open
Abstract
Extremophilic endoxylanases grabbed attention in recent years due to their applicability under harsh conditions of several industrial processes. Thermophilic, alkaliphilic, and acidophilic endoxylanases found their employability in bio-bleaching of paper pulp, bioconversion of lignocellulosic biomass into xylooligosaccharides, bioethanol production, and improving the nutritious value of bread and other bakery products. Xylanases obtained from extremophilic bacteria and archaea are considered better than fungal sources for several reasons. For example, enzymatic activity under broad pH and temperature range, low molecular weight, cellulase-free activity, and longer stability under extreme conditions of prokaryotic derived xylanases make them a good choice. In addition, a short life span, easy cultivation/harvesting methods, higher yield, and rapid DNA manipulations of bacterial and archaeal cells further reduces the overall cost of the product. This review focuses on the diversity of prokaryotic endoxylanases, their characteristics, and their functional attributes. Besides, the molecular mechanisms of their extreme behavior have also been presented here.
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Affiliation(s)
- Digvijay Verma
- Department of Environmental Microbiology, Babasaheb Bhimrao Ambedkar University, Lucknow, India
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Chauhan AK, Choudhury B. Synthetic dyes degradation using lignolytic enzymes produced from Halopiger aswanensis strain ABC_IITR by Solid State Fermentation. CHEMOSPHERE 2021; 273:129671. [PMID: 33517115 DOI: 10.1016/j.chemosphere.2021.129671] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2020] [Revised: 11/01/2020] [Accepted: 01/13/2021] [Indexed: 06/12/2023]
Abstract
The present work focuses on studying the degradation of industrial synthetic dyes, which poses serious health hazards and a drastic impact on the environment. Currently available enzymatic processes have higher production and operational costs. However, most enzymes are active at acidic pH, which limits its application in textile dye degradation. This problem can be overcome by lignolytic enzymes obtained from halo-alkaliphile through Solid State Fermentation (SSF) using wheat bran (agro-byproduct) as a substrate. The major lignolytic enzymes studied were Lignin Peroxidase (LiP), Manganese Peroxidase (MnP), and laccase. The results demonstrated the highest activity of 215.4 ± 1.57 of LiP, 36.8 ± 2.38 of MnP, and 8.34 ± 0.21 IU/gds of laccase. Crude enzymes were used to treat synthetic dyes (mainly azo dyes), and their potential for its degradation was confirmed by spectrophotometric, GC-MS, and HPLC analysis. The highest decolorization of 82-93% of Malachite Green (MG) was achieved in LiP and MnP mediated reaction system within 2 hours. The laccase reaction system showed degradation of 53.87% of methyl orange without adding any redox mediator. After obtaining these results, the crude LiP and MnP in the reaction system were further subjected to decolorization at a higher MG concentration of 100-600 mg/L without a redox mediator. As a result, both LiP and MnP decolorized MG by 72-89%. Further, GC-MS analysis of MG biodegradation products confirmed the formation of less toxic low molecular weight products such as benzaldehyde and methanone.
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Affiliation(s)
- Ajay Kumar Chauhan
- Department of Biotechnology, Indian Institute of Technology, Roorkee, Uttarakhand, 24667, India
| | - Bijan Choudhury
- Department of Biotechnology, Indian Institute of Technology, Roorkee, Uttarakhand, 24667, India.
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15
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Pavarina GC, Lemos EGDM, Lima NSM, Pizauro JM. Characterization of a new bifunctional endo-1,4-β-xylanase/esterase found in the rumen metagenome. Sci Rep 2021; 11:10440. [PMID: 34001974 PMCID: PMC8128909 DOI: 10.1038/s41598-021-89916-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 04/26/2021] [Indexed: 12/13/2022] Open
Abstract
Metagenomic data mining of the Nellore cattle rumen microbiota identified a new bifunctional enzyme, endo-1,4-β-xylanase/esterase, which was subsequently overexpressed in E. coli BL21 (DE3). This enzyme was stable at pH intervals of 5 to 6.5 and temperatures between 30 and 45 °C, and under the test conditions, it had a Vmax of 30.959 ± 2.334 µmol/min/mg, Km of 3.6 ± 0.6 mM and kcat of 2.323 ± 175 s-1. Additionally, the results showed that the enzyme is tolerant to NaCl and organic solvents and therefore is suitable for industrial environments. Xylanases are widely applicable, and the synergistic activity of endo-1,4-β-xylanase/esterase in a single molecule will improve the degradation efficiency of heteroxylans via the creation of xylanase binding sites. Therefore, this new molecule has the potential for use in lignocellulosic biomass processing and as an animal feed food additive and could improve xylooligosaccharide production efficiency.
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Affiliation(s)
- Gabriella Cavazzini Pavarina
- Technology Department, School of Agricultural and Veterinarian Sciencess, Sao Paulo State University (Unesp), Via de Acesso Prof. Paulo Donato Castellane S/N, km 5, Sao Paulo, Brazil.,Graduate Program in Agricultural and Livestock Microbiology, School of Agricultural and Veterinarian Sciences, Sao Paulo State University (Unesp), Jaboticabal, Sao Paulo, Brazil
| | - Eliana Gertrudes de Macedo Lemos
- Technology Department, School of Agricultural and Veterinarian Sciencess, Sao Paulo State University (Unesp), Via de Acesso Prof. Paulo Donato Castellane S/N, km 5, Sao Paulo, Brazil.,Molecular Biology Laboratory, Bioenergy Research Institute (IPBEN), Jaboticabal, Sao Paulo, Brazil
| | - Natália Sarmanho Monteiro Lima
- Technology Department, School of Agricultural and Veterinarian Sciencess, Sao Paulo State University (Unesp), Via de Acesso Prof. Paulo Donato Castellane S/N, km 5, Sao Paulo, Brazil.,Graduate Program in Agricultural and Livestock Microbiology, School of Agricultural and Veterinarian Sciences, Sao Paulo State University (Unesp), Jaboticabal, Sao Paulo, Brazil
| | - João Martins Pizauro
- Technology Department, School of Agricultural and Veterinarian Sciencess, Sao Paulo State University (Unesp), Via de Acesso Prof. Paulo Donato Castellane S/N, km 5, Sao Paulo, Brazil.
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Wang J, Liang J, Li Y, Tian L, Wei Y. Characterization of efficient xylanases from industrial-scale pulp and paper wastewater treatment microbiota. AMB Express 2021; 11:19. [PMID: 33464408 PMCID: PMC7815853 DOI: 10.1186/s13568-020-01178-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 12/31/2020] [Indexed: 02/08/2023] Open
Abstract
Xylanases are widely used enzymes in the food, textile, and paper industries. Most efficient xylanases have been identified from lignocellulose-degrading microbiota, such as the microbiota of the cow rumen and the termite hindgut. Xylanase genes from efficient pulp and paper wastewater treatment (PPWT) microbiota have been previously recovered by metagenomics, assigning most of the xylanase genes to the GH10 family. In this study, a total of 40 GH10 family xylanase genes derived from a certain PPWT microbiota were cloned and expressed in Escherichia coli BL21 (DE3). Among these xylanase genes, 14 showed xylanase activity on beechwood substrate. Two of these, PW-xyl9 and PW-xyl37, showed high activities, and were purified to evaluate their xylanase properties. Values of optimal pH and temperature for PW-xyl9 were pH 7 and 60 ℃, respectively, while those for PW-xyl37 were pH 7 and 55 ℃, respectively; their specific xylanase activities under optimal conditions were 470.1 U/mg protein and 113.7 U/mg protein, respectively. Furthermore, the Km values of PW-xyl9 and PW-xyl37 were determined as 8.02 and 18.8 g/L, respectively. The characterization of these two xylanases paves the way for potential application in future pulp and paper production and other industries, indicating that PPWT microbiota has been an undiscovered reservoir of efficient lignocellulase genes. This study demonstrates that a metagenomic approach has the potential to screen efficient xylanases of uncultured microorganisms from lignocellulose-degrading microbiota. In a similar way, other efficient lignocellulase genes might be identified from PPWT treatment microbiota in the future.
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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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Yu H, Zhao S, Fan Y, Hu C, Lu W, Guo L. Cloning and heterologous expression of a novel halo/alkali-stable multi-domain xylanase (XylM18) from a marine bacterium Marinimicrobium sp. strain LS-A18. Appl Microbiol Biotechnol 2019; 103:8899-8909. [DOI: 10.1007/s00253-019-10140-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 08/06/2019] [Accepted: 09/12/2019] [Indexed: 10/25/2022]
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