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1.
Toxicon ; 180: 43-48, 2020 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-32298663

RESUMO

Zearalenone, an oestogenic mycotoxin produced by Fusarium sp., occurs naturally in agricultural commodities. Economic losses and health concerns associated to mycotoxins has attracted research interest towards exploring novel approaches to detoxify mycotoxin-contaminated food and feed. The aim of the present work was to study the ability of 11 aflatoxin-degrading Bacillus strains to degrade ZEA. In addition, a qualitative assessment of protease, amylase and cellulase activity of the studied Bacillus strains was made. All strains were able to degrade 58-96.9% ZEA after 72 h. Toxicity towards Artemia salina was significantly reduced (P < 0.0001). Degradation extracts fluorescence decreased 50% indicating a probable cleavage of the lactone ring. Strains RC1A, RC3A and RC6A showed a remarkable enzymatic activity, showing potential to be used as feed additives.


Assuntos
Aflatoxinas/metabolismo , Amilases/metabolismo , Bacillus/metabolismo , Celulases/metabolismo , Peptídeo Hidrolases/metabolismo , Zearalenona/metabolismo , Agricultura , Inativação Metabólica
2.
Arch Microbiol ; 202(5): 1117-1126, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32060600

RESUMO

Gayal (Bos frontalis) of the Yunnan region is well adapted to harsh environmental conditions. Its diet consists predominantly of bamboo, reeds, and woody plants, suggesting that the rumen of this species contains many fiber-degrading bacteria and cellulases. The aim of this study was to identify and modify specific cellulases found in the gayal rumen. In the present study, a directed evolution strategy of error-prone PCR was employed to improve the activity or optimal temperature of a cellulase gene (CMC-1) isolated from gayal rumen. The CMC-1 gene was heterologously expressed in Escherichia coli (E. coli) BL21, and the recombinant CMC-1 protein hydrolyzed carboxyl methyl cellulose (CMC) with an optimal activity at pH 5.0 and 50 °C. A library of mutated ruminal CMC-1 genes was constructed and a mutant EP-15 gene was identified. Sequencing analysis revealed that EP-15 and CMC-1 belonged to the glycosyl hydrolase family 5 (GHF5) and had the highest homology to a cellulase (Accession No. WP_083429257.1) from Prevotellaceae bacterium, HUN156. There were similar predicted GH5 domains in EP-15 and CMC-1. The EP-15 gene was heterologously expressed and exhibited cellulase activity in E. coli BL21 at pH 5.0, but the optimum temperature for its activity was reduced from that of CMC-1 (50 °C) to 45 °C, which was closer to the physiological temperature of the rumen (40 °C). The cellulase activity of EP-15 was about two times higher than CMC-1 at 45 °C or PH 5.0, and also was more stable in response to temperature and pH changes compared to CMC-1. This study successfully isolated and modified a ruminal cellulase gene from metagenomics library of Yunnan gayal. Our findings may obtain a useful cellulase in future applications and present the first evidence of modified cellulases in the gayal rumen.


Assuntos
Bactérias/genética , Carboximetilcelulose Sódica/metabolismo , Celulases/genética , Glicosídeo Hidrolases/genética , Rúmen/microbiologia , Animais , Bovinos , Celulases/metabolismo , China , Clonagem Molecular , Biblioteca Gênica , Concentração de Íons de Hidrogênio , Metagenoma , Metagenômica , Proteínas Recombinantes/metabolismo , Especificidade por Substrato
3.
Appl Biochem Biotechnol ; 190(2): 448-463, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31378843

RESUMO

Cellulases, as environmentally appropriate catalysts specifically acting on cellulosic substrates, are important for the industrial conversion of lignocellulose and modification of cellulose products. After decades of research, a fundamental understanding of cellulase-mediated hydrolysis of cellulose is that its ability to processively act as a key for the complete enzymatic hydrolysis of natural crystalline cellulose. Two types of processive cellulases are known: exoglucanases and processive endoglucanases. Exoglucanases are typical processive enzymes, and they have been studied in detail so that their modes of action and mechanisms are reasonably well characterized. Conversely, endoglucanases are less well characterized because of the non-universality and structural diversity. However, processive endoglucanases have certain characteristics that exoglucanases lack such as hydrolysis product diversity and independent hydrolyze natural crystalline cellulose. Therefore, besides the conversion of cellulose to monosaccharide, they might be useful for modification of fibrous substrates and preparation of cellulose oligosaccharides. Herein, we review in detail the sources, hydrolysis products, application, and possible hydrolysis mechanisms of processive endoglucanases.


Assuntos
Celulase/metabolismo , Bactérias/enzimologia , Catálise , Celulases/metabolismo , Celulose/metabolismo , Fungos/enzimologia
4.
Biosci Biotechnol Biochem ; 84(2): 238-246, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31625450

RESUMO

The Cel genes from Bacillus licheniformis MSB03 were cloned and expressed to investigate binding ability on clay minerals and sea sand at pH ranging 3 to 9. FTIR analysis has been done to characterize bound enzymes on clay minerals. Subsequent, surveying of NCBI database for extracellular enzymes of soil bacteria was carried out. Among the five cloned Cel enzymes assayed for binding to clay minerals, only Cel5H enzyme had the binding ability. Enzyme Cel5H exhibited highest binding to montmorillonite followed by kaolinite and sea sand. Interestingly, Cel5H had higher pI value of 9.24 than other proteins (5.2-5.7). Cel5H binding to montmorillonite was shown to be negatively affected below pH 3 and above pH 9. Infrared absorption spectra of the Cel5H-montmorillonite complexes showed distinct peaks for clay minerals and bound proteins. Furthermore, database survey of soil bacterial extracellular enzymes revealed that Bacillus species enzymes had higher pI than other soil bacterial enzymes.


Assuntos
Bacillus licheniformis/enzimologia , Celulases/metabolismo , Argila , Bases de Dados de Proteínas , Ponto Isoelétrico , Minerais/metabolismo , Microbiologia do Solo , Celulases/genética , Clonagem Molecular , Hidrólise , Ligação Proteica , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo
5.
ChemSusChem ; 13(1): 106-110, 2020 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-31593363

RESUMO

The activity of ß-glucosidases-the enzymes responsible for the final step in the enzymatic conversion of cellulose to glucose-can be maintained and manipulated under mechanochemical conditions in the absence of bulk solvent, either through an unexpected stabilization effect of inert surfaces, or by altering the enzymatic equilibrium. The reported results illustrate unique aspects of mechanoenzymatic reactions that are not observable in conventional aqueous solutions. They also represent the first reported strategies to enhance activity and favor either direction of the reaction under mechanochemical conditions.


Assuntos
Celulases/metabolismo , Catálise , Celulose/química , Cinética , Fenômenos Mecânicos , Polímeros/química , Propriedades de Superfície
6.
PLoS One ; 14(11): e0224803, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31730665

RESUMO

Talaromyces leycettanus JCM12802 is a great producer of thermophilic glycoside hydrolases (GHs). In this study, two cellulases (TlCel5A and TlCel6A) belonging to GH5 and GH6 respectively were expressed in Pichia pastoris and functionally characterized. The enzymes had acidic and thermophilic properties, showing optimal activities at pH 3.5-4.5 and 75-80°C, and retained stable at temperatures up to 60°C and over a broad pH range of 2.0-8.0. TlCel5A and TlCel6A acted against several cellulose substrates with varied activities (3,101.1 vs. 92.9 U/mg to barley ß-glucan, 3,905.6 U/mg vs. 109.0 U/mg to lichenan, and 840.3 and 0.09 U/mg to CMC-Na). When using Avicel, phosphoric acid swollen cellulose (PASC) or steam-exploded corn straw (SECS) as the substrate, combination of TlCel5A and TlCel6A showed significant synergistic action, releasing more reduced sugars (1.08-2.87 mM) than the individual enzymes. These two cellulases may represent potential enzyme additives for the efficient biomass conversion and bioethanol production.


Assuntos
Celulases/metabolismo , Celulose/metabolismo , Talaromyces/enzimologia , Temperatura , Sequência de Aminoácidos , Celulases/química , Estabilidade Enzimática , Concentração de Íons de Hidrogênio , Hidrólise , Cinética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Especificidade por Substrato
7.
Proc Natl Acad Sci U S A ; 116(49): 24729-24737, 2019 12 03.
Artigo em Inglês | MEDLINE | ID: mdl-31740605

RESUMO

The order Coleoptera (beetles) is arguably the most speciose group of animals, but the evolutionary history of beetles, including the impacts of plant feeding (herbivory) on beetle diversification, remain poorly understood. We inferred the phylogeny of beetles using 4,818 genes for 146 species, estimated timing and rates of beetle diversification using 89 genes for 521 species representing all major lineages and traced the evolution of beetle genes enabling symbiont-independent digestion of lignocellulose using 154 genomes or transcriptomes. Phylogenomic analyses of these uniquely comprehensive datasets resolved previously controversial beetle relationships, dated the origin of Coleoptera to the Carboniferous, and supported the codiversification of beetles and angiosperms. Moreover, plant cell wall-degrading enzymes (PCWDEs) obtained from bacteria and fungi via horizontal gene transfers may have been key to the Mesozoic diversification of herbivorous beetles-remarkably, both major independent origins of specialized herbivory in beetles coincide with the first appearances of an arsenal of PCWDEs encoded in their genomes. Furthermore, corresponding (Jurassic) diversification rate increases suggest that these novel genes triggered adaptive radiations that resulted in nearly half of all living beetle species. We propose that PCWDEs enabled efficient digestion of plant tissues, including lignocellulose in cell walls, facilitating the evolution of uniquely specialized plant-feeding habits, such as leaf mining and stem and wood boring. Beetle diversity thus appears to have resulted from multiple factors, including low extinction rates over a long evolutionary history, codiversification with angiosperms, and adaptive radiations of specialized herbivorous beetles following convergent horizontal transfers of microbial genes encoding PCWDEs.


Assuntos
Biodiversidade , Evolução Biológica , Besouros/genética , Transferência Genética Horizontal , Genoma de Inseto , Animais , Bactérias/enzimologia , Bactérias/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Parede Celular/química , Parede Celular/metabolismo , Celulases/genética , Celulases/metabolismo , Besouros/enzimologia , Besouros/microbiologia , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Fungos/enzimologia , Fungos/genética , Herbivoria/genética , Proteínas de Insetos/genética , Proteínas de Insetos/metabolismo , Lignina/química , Lignina/metabolismo , Filogenia , Plantas/química , Polissacarídeo-Liase/genética , Polissacarídeo-Liase/metabolismo , Polissacarídeos/química , Polissacarídeos/metabolismo
8.
Proc Natl Acad Sci U S A ; 116(46): 23061-23067, 2019 11 12.
Artigo em Inglês | MEDLINE | ID: mdl-31666327

RESUMO

Cellulase enzymes deconstruct recalcitrant cellulose into soluble sugars, making them a biocatalyst of biotechnological interest for use in the nascent lignocellulosic bioeconomy. Cellobiohydrolases (CBHs) are cellulases capable of liberating many sugar molecules in a processive manner without dissociating from the substrate. Within the complete processive cycle of CBHs, dissociation from the cellulose substrate is rate limiting, but the molecular mechanism of this step is unknown. Here, we present a direct comparison of potential molecular mechanisms for dissociation via Hamiltonian replica exchange molecular dynamics of the model fungal CBH, Trichoderma reesei Cel7A. Computational rate estimates indicate that stepwise cellulose dethreading from the binding tunnel is 4 orders of magnitude faster than a clamshell mechanism, in which the substrate-enclosing loops open and release the substrate without reversing. We also present the crystal structure of a disulfide variant that covalently links substrate-enclosing loops on either side of the substrate-binding tunnel, which constitutes a CBH that can only dissociate via stepwise dethreading. Biochemical measurements indicate that this variant has a dissociation rate constant essentially equivalent to the wild type, implying that dethreading is likely the predominant mechanism for dissociation.


Assuntos
Celulases/química , Proteínas Fúngicas/química , Trichoderma/enzimologia , Sítios de Ligação , Domínio Catalítico , Celulases/metabolismo , Celulose/química , Celulose/metabolismo , Proteínas Fúngicas/metabolismo , Cinética , Simulação de Dinâmica Molecular , Trichoderma/química
9.
Appl Microbiol Biotechnol ; 103(21-22): 8711-8724, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31628521

RESUMO

Biocatalysts provide a major advantage to bio-based economy over chemical catalysts by catalyzing various useful transformations in an environment friendly manner along with other major benefits of selectivity, specificity, and low energy consumption. Since last decade, cellulase is the 3rd highest used enzyme in industry in various processes. Xylanase is also one amongst the widely used enzymes, and many industrial applications require synergistic action of both of these enzymes. These applications predominantly include bioethanol production, deinking of waste paper, animal feed processing, food processing, paper and pulp production, removal of fine fibers from textile material (biostoning), and pharmaceuticals. These enzymes are produced by microorganisms (fungi and bacteria), and hence, the microorganisms producing both cellulases and xylanases are in high demand by these industries. This review focuses on the synergistic applications of cellulase and xylanase enzymes across various industrial sectors. It also discusses the potential applications and the need of the microbial systems (fungi and bacteria) secreting both of these enzymes and the future prospects of their development into an integral part of various industrial processes.


Assuntos
Bactérias/enzimologia , Reatores Biológicos/microbiologia , Celulases/metabolismo , Endo-1,4-beta-Xilanases/metabolismo , Fungos/enzimologia , Bactérias/metabolismo , Biocombustíveis/microbiologia , Fungos/metabolismo , Indústrias
10.
Proc Natl Acad Sci U S A ; 116(45): 22545-22551, 2019 11 05.
Artigo em Inglês | MEDLINE | ID: mdl-31636211

RESUMO

Two fluorescence-tagged carbohydrate-binding modules (CBMs), which specifically bind to crystalline (CBM2a-RRedX) and paracrystalline (CBM17-FITC) cellulose, were used to differentiate the supramolecular cellulose structures in bleached softwood Kraft fibers during enzyme-mediated hydrolysis. Differences in CBM adsorption were elucidated using confocal laser scanning microscopy (CLSM), and the structural changes occurring during enzyme-mediated deconstruction were quantified via the relative fluorescence intensities of the respective probes. It was apparent that a high degree of order (i.e., crystalline cellulose) occurred at the cellulose fiber surface, which was interspersed by zones of lower structural organization and increased cellulose accessibility. Quantitative image analysis, supported by 13C NMR, scanning electron microscopy (SEM) imaging, and fiber length distribution analysis, showed that enzymatic degradation predominates at these zones during the initial phase of the reaction, resulting in rapid fiber fragmentation and an increase in cellulose surface crystallinity. By applying this method to elucidate the differences in the enzyme-mediated deconstruction mechanisms, this work further demonstrated that drying decreased the accessibility of enzymes to these disorganized zones, resulting in a delayed onset of degradation and fragmentation. The use of fluorescence-tagged CBMs with specific recognition sites provided a quantitative way to elucidate supramolecular substructures of cellulose and their impact on enzyme accessibility. By designing a quantitative method to analyze the cellulose ultrastructure and accessibility, this study gives insights into the degradation mechanism of cellulosic substrates.


Assuntos
Proteínas de Bactérias/química , Celulases/química , Cellulomonas/enzimologia , Celulose/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Biocatálise , Celulases/genética , Celulases/metabolismo , Cellulomonas/química , Cellulomonas/genética , Celulose/metabolismo , Fluorescência , Hidrólise , Cinética , Microscopia Confocal
11.
Carbohydr Res ; 485: 107811, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31526927

RESUMO

The use of Zophobas morio extracts in the aspect of cellulose hydrolysis is presented for the first time. The aim of this study was to investigate the action of enzymes obtained from Z. morio on cellulose hydrolysis and to determine their influence on the structural properties of cellulose with use the Fourier transform infrared spectroscopy (FTIR) and gel permeation chromatography (GPC). Cellulose hydrolysis products were analyzed by high performance liquid chromatography (HPLC). This analysis indicated that microcrystalline cellulose with smaller particle size was more susceptible to enzymatically treatment. Moreover, our investigation of cellulase activity showed a different profile of the used enzyme during particular developmental stages of Z. morio. Midgut extracts obtained from adult insects are more effective in degrading cellulose than extracts from larvae. The analysis of cellulose hydrolysis confirms that the efficiency of this reaction also depends on the structure of cellulosic materials and internal conditions of enzymatic reaction. In this study the cellulolytic activity of Z. morio midgut extracts showed that these insects could be valuable sources of cellulases.


Assuntos
Celulases/metabolismo , Celulose/química , Besouros/enzimologia , Animais , Hidrólise
12.
Enzyme Microb Technol ; 130: 109370, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31421724

RESUMO

Secretome evaluations of lignocellulose-decay basidiomycetes can reveal new enzymes in selected fungal species that degrade specific substrates. Proteins discovered in such studies can support biorefinery development. Brown-rot (Gloeophyllum trabeum) and white-rot (Pleurotus ostreatus) fungi growing in sugarcane bagasse solid-state cultures produced 119 and 63 different extracellular proteins, respectively. Several of the identified enzymes are suitable for in vitro biomass conversion, including a range of cellulases (endoglucanases, cellobiohydrolases and ß-glucosidases), hemicellulases (endoxylanases, α-arabinofuranosidases, α-glucuronidases and acetylxylan esterases) and carbohydrate-active auxiliary proteins, such as AA9 lytic polysaccharide monooxygenase, AA1 laccase and AA2 versatile peroxidase. Extracellular oxalate decarboxylase was also detected in both fungal species, exclusively in media containing sugarcane bagasse. Interestingly, intracellular AA6 quinone oxidoreductases were also exclusively produced under sugarcane bagasse induction in both fungi. These enzymes promote quinone redox cycling, which is used to produce Fenton's reagents by lignocellulose-decay fungi. Hitherto undiscovered hypothetical proteins that are predicted in lignocellulose-decay fungi genomes appeared in high relative abundance in the cultures containing sugarcane bagasse, which suggests undisclosed, new biochemical mechanisms that are used by lignocellulose-decay fungi to degrade sugarcane biomass. In general, lignocellulose-decay fungi produce a number of canonical hydrolases, as well as some newly observed enzymes, that are suitable for in vitro biomass digestion in a biorefinery context.


Assuntos
Basidiomycota/metabolismo , Celulose/metabolismo , Lignina/metabolismo , Metaboloma , Pleurotus/metabolismo , Saccharum/metabolismo , Biomassa , Celulases/metabolismo , Celulose 1,4-beta-Celobiosidase/metabolismo , Proteínas Fúngicas/metabolismo , Glucose/metabolismo , Madeira/metabolismo , Madeira/microbiologia
13.
Int J Mol Sci ; 20(17)2019 Aug 22.
Artigo em Inglês | MEDLINE | ID: mdl-31443450

RESUMO

Trichoderma reesei is a biotechnologically important filamentous fungus with the remarkable ability to secrete large amounts of enzymes, whose production is strongly affected by both the carbon and nitrogen sources. While the carbon metabolism regulators are extensively studied, the regulation of enzyme production by the nitrogen metabolism regulators is still poorly understood. In this study, the GATA transcription factor Are1, which is an orthologue of the Aspergillus global nitrogen regulator AREA, was identified and characterized for its functions in regulation of both protease and cellulase production in T. reesei. Deletion of the are1 gene abolished the capability to secrete proteases, and complementation of the are1 gene rescued the ability to produce proteases. Quantitative RT-PCR analysis revealed that the transcripts of protease genes apw1 and apw2 were also significantly reduced in the Δare1 strain when grown in the medium with peptone as the nitrogen source. In addition, deletion of are1 resulted in decreased cellulase production in the presence of (NH4)2SO4. Consistent with the reduction of cellulase production, the transcription levels of the major cellulase genes, including cbh1, cbh2, egl1, and egl2, were dramatically decreased in Δare1. Sequence analysis showed that all promoter regions of the tested protease and cellulase genes contain the consensus GATA elements. However, the expression levels of the major cellulase transcription activator Xyr1 and the repressor Cre1 had no significant difference between Δare1 and the parental strain QM9414, indicating that the regulatory mechanism deserves further investigation. Taken together, these results demonstrate the important role of Are1 in the regulation of protease and cellulase production in T. reesei, although these processes depend on the kind of nitrogen sources. The findings in this study contribute to the understanding of the regulation network of carbon and nitrogen sources in filamentous fungi.


Assuntos
Celulases/genética , Regulação Fúngica da Expressão Gênica , Peptídeo Hidrolases/genética , Esterol O-Aciltransferase/metabolismo , Fatores de Transcrição/metabolismo , Trichoderma/genética , Trichoderma/metabolismo , Celulases/metabolismo , Espaço Extracelular , Deleção de Genes , Peptídeo Hidrolases/metabolismo , Fenótipo , Filogenia , Trichoderma/classificação
14.
An Acad Bras Cienc ; 91(3): e20180583, 2019 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-31365652

RESUMO

Isolation and screening of new fungal strains from extreme and understudied environments, such as caves, is a promising approach to find higher yields enzyme producers. Cellulolytic fungal strains isolated from a Brazilian cave were evaluated for their enzymatic production after submerged (SmF) and solid-state fermentation (SSF). After SmF, three strains were selected for their high enzymatic activities: Aspergillus ustus for endoglucanase (4.76 U/mg), Talaromyces bruneus for ß-glucosidase (11.71 U/mg) and Aspergillus sp. (CBMAI 1926) for total cellulase (1.70 U/mg). After SSF, these strains, showed better yields compared to the reference strain Aspergillus niger 3T5B8. Aspergillus sp. (CBMAI 1926) stood out as a new species that expressed activity of total cellulases (0.10 U/mg) and low protein concentration (0.44 mg/mL). In conclusion, these isolated strains have a more efficient and promising cellulolytic enzyme complex that can be used in fermentation and saccharification processes with a lower protein concentration and a higher enzymatic activity than the reference strain. Therefore, beside the new genetic material characterized, our study highlights the benefits of cave extreme environments exploitation to find new potentially valuable strains.


Assuntos
Cavernas , Celulases/metabolismo , Ambientes Extremos , Fungos/metabolismo , Brasil , Fungos/classificação
15.
Arch Microbiol ; 201(10): 1385-1397, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31338542

RESUMO

Rumen microbial community harbors a distinct genetic reservoir of potent carbohydrate-active enzymes (CAZyme) that functions efficiently for the deconstruction of plant biomass. Based on this premise, metagenomics approach was applied to characterize the rumen microbial community and identify carbohydrate-active genes of Bos taurus (cow) and Bubalus bubalis (buffalo) fed on green or dry roughage. Metadata was generated from the samples: green roughage-fed cow (NDC_GR), buffalo (NDB_GR) and dry roughage-fed cow (NDC_DR), buffalo (NDB_DR). Phylogenetic analysis revealed the dominance of Bacteroidetes, Firmicutes, Proteobacteria, Actinobacteria and Fibrobacter in all the four samples, covering 90-96% of the total bacterial population. On finer resolution, higher abundance of bacterial genera Fibrobacter, Bacteroides, Clostridium, Prevotella and Ruminococcus involved in plant biomass hydrolysis was observed in NDB_DR. Functional annotation using dbCAN annotation algorithm identified 28.13%, 8.08% 10.93% and 12.53% of the total contigs as putatively carbohydrate-active against NDC_GR, NDB_GR, NDC_DR and NDB_DR, respectively. Additional profiling of CAZymes revealed an over representation and diversity of putative glycoside hydrolases (GHs) in the animals fed on dry roughage with substantial enrichments of genes encoding GHs from families GH2, GH3, GH13 and GH43. GHs of families GH45, GH12, GH113, GH128, GH54 and GH27 were observed exclusively in NDB_DR metagenome. A higher abundance of cellulases, hemicellulases, debranching and oligosaccharide hydrolyzing enzymes was revealed in NDB_DR metagenome. Accordingly, it can be concluded that buffalo rumen microbiome are more efficient in plant biomass hydrolysis. The present study provides a deep understanding of the shifts in microbial community and plant polysaccharide deconstructing capabilities of rumen microbiome in response to changes in the feed type and host animal. Activity-specific microbial consortia procured from these animals can be used further for efficient plant biomass hydrolysis. The study also establishes the utility of rumen microbiome as a unique resource for mining diverse lignocellulolytic enzymes.


Assuntos
Bactérias/classificação , Bactérias/enzimologia , Búfalos , Bovinos , Dieta , Microbiota/fisiologia , Rúmen/microbiologia , Animais , Bactérias/genética , Bacteroidetes/genética , Búfalos/microbiologia , Bovinos/microbiologia , Celulases/metabolismo , Dieta/veterinária , Fibras na Dieta , Glicosídeo Hidrolases/metabolismo , Metagenoma , Metagenômica , Consórcios Microbianos/genética , Filogenia
16.
J Biosci Bioeng ; 128(6): 637-654, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31204199

RESUMO

Cellulolytic enzymes play a key role on conversion of lignocellulosic plant biomass to biofuels and biochemicals in sugar platform biorefineries. In this review, we survey composite carbohydrate-active enzymes (CAZymes) among groups of cellulolytic fungi and bacteria that exist under aerobic and anaerobic conditions. Recent advances in designing effective cellulase mixtures are described, starting from the most complex microbial consortium-based enzyme preparations, to single-origin enzymes derived from intensively studied cellulase producers such as Trichoderma reesei, Talaromyces cellulolyticus, and Penicellium funiculosum, and the simplest minimal enzyme systems comprising selected sets of mono-component enzymes tailor-made for specific lignocellulosic substrates. We provide a comprehensive update on studies in developing high-performance cellulases for biorefineries.


Assuntos
Celulases/metabolismo , Biocombustíveis , Biomassa , Penicillium/enzimologia , Talaromyces/enzimologia , Trichoderma/enzimologia
17.
Microb Cell Fact ; 18(1): 97, 2019 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-31151435

RESUMO

BACKGROUND: Transglycosylation represents one of the most promising approaches for obtaining novel glycosides, and plant phenols and polyphenols are emerging as one of the best targets for creating new molecules with enhanced capacities. These compounds can be found in diet and exhibit a wide range of bioactivities, such as antioxidant, antihypertensive, antitumor, neuroprotective and anti-inflammatory, and the eco-friendly synthesis of glycosides from these molecules can be a suitable alternative for increasing their health benefits. RESULTS: Transglycosylation experiments were carried out using different GH3 ß-glucosidases from the fungus Talaromyces amestolkiae. After a first screening with a wide variety of potential transglycosylation acceptors, mono-glucosylated derivatives of hydroxytyrosol, vanillin alcohol, 4-hydroxybenzyl alcohol, and hydroquinone were detected. The reaction products were analyzed by thin-layer chromatography, high-pressure liquid chromatography, and mass spectrometry. Hydroxytyrosol and vanillyl alcohol were selected as the best options for transglycosylation optimization, with a final conversion yield of 13.8 and 19% of hydroxytyrosol and vanillin glucosides, respectively. NMR analysis confirmed the structures of these compounds. The evaluation of the biological effect of these glucosides using models of breast cancer cells, showed an enhancement in the anti-proliferative capacity of the vanillin derivative, and an improved safety profile of both glucosides. CONCLUSIONS: GH3 ß-glucosidases from T. amestolkiae expressed in P. pastoris were able to transglycosylate a wide variety of acceptors. Between them, phenolic molecules like hydroxytyrosol, vanillin alcohol, 4-hydroxybenzyl alcohol, and hydroquinone were the most suitable for its interesting biological properties. The glycosides of hydroxytyrosol and vanillin were tested, and they improved the biological activities of the original aglycons on breast cancer cells.


Assuntos
Neoplasias da Mama , Celulases/metabolismo , Glicosídeos/farmacologia , Talaromyces/enzimologia , Benzaldeídos/metabolismo , Álcoois Benzílicos/metabolismo , Celulases/química , Celulases/isolamento & purificação , Glicosídeos/química , Glicosídeos/isolamento & purificação , Glicosilação , Humanos , Hidroquinonas/metabolismo , Células MCF-7 , Álcool Feniletílico/análogos & derivados , Álcool Feniletílico/metabolismo , Especificidade por Substrato
18.
Pol J Microbiol ; 68(1): 105-114, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31050258

RESUMO

Bacteria from the genus Bacillus are a rich source of commercial enzymes, including amylases, proteases, cellulases, glucose isomerase, and pullulanase. Cellulases account for 15% of the global market of industrial enzymes; thus, new microorganisms producing cellulases in a higher concentration and new ingredients, which can enhance the level of enzyme synthesis, are still needed. Many of cellulose-degrading microorganisms have been isolated so far and characterized in various regions of the world. In this study, we were looking for the bacteria isolated from the natural environment with the high cellulolytic potential, which could be used as components of a biopreparation to accelerate decomposition of postharvest leftovers in agriculture. The 214 bacterial strains were isolated from environmental samples rich in cellulose and their ability to synthesize cellulases were examined using the diffusion method. Six strains, which have the highest diameter of clearing zone both for biomass and supernatant, were selected for identification. Optimization of biosynthesis of the cellulose-degrading enzymes indicated that optimal temperature of this process fluctuated in the range of 21-42°C (depending on the strain and carbon source). The highest cellulolytic activity was observed for the isolates designed as 4/7 (identified as Bacillus subtilis) and 4/18 (identified as Bacillus licheniformis) in a temperature of 32°C. With the use of a desirability function methodology, the optimal medium composition to achieve a simple, cost-efficient process of cellulases production was developed for both strains. These experiments show that microorganisms isolated from natural environmental samples have unique properties and potential for commercial applications (e.g. for biopreparations production).Bacteria from the genus Bacillus are a rich source of commercial enzymes, including amylases, proteases, cellulases, glucose isomerase, and pullulanase. Cellulases account for 15% of the global market of industrial enzymes; thus, new microorganisms producing cellulases in a higher concentration and new ingredients, which can enhance the level of enzyme synthesis, are still needed. Many of cellulose-degrading microorganisms have been isolated so far and characterized in various regions of the world. In this study, we were looking for the bacteria isolated from the natural environment with the high cellulolytic potential, which could be used as components of a biopreparation to accelerate decomposition of postharvest leftovers in agriculture. The 214 bacterial strains were isolated from environmental samples rich in cellulose and their ability to synthesize cellulases were examined using the diffusion method. Six strains, which have the highest diameter of clearing zone both for biomass and supernatant, were selected for identification. Optimization of biosynthesis of the cellulose-degrading enzymes indicated that optimal temperature of this process fluctuated in the range of 21­42°C (depending on the strain and carbon source). The highest cellulolytic activity was observed for the isolates designed as 4/7 (identified as Bacillus subtilis) and 4/18 (identified as Bacillus licheniformis) in a temperature of 32°C. With the use of a desirability function methodology, the optimal medium composition to achieve a simple, cost-efficient process of cellulases production was developed for both strains. These experiments show that microorganisms isolated from natural environmental samples have unique properties and potential for commercial applications (e.g. for biopreparations production).


Assuntos
Bacillus licheniformis/enzimologia , Bacillus licheniformis/metabolismo , Bacillus subtilis/enzimologia , Bacillus subtilis/metabolismo , Celulases/metabolismo , Celulose/metabolismo , Bacillus licheniformis/crescimento & desenvolvimento , Bacillus licheniformis/isolamento & purificação , Bacillus subtilis/crescimento & desenvolvimento , Bacillus subtilis/isolamento & purificação , Biomassa , Nitrogênio/metabolismo , Microbiologia do Solo , Temperatura
19.
Protoplasma ; 256(4): 1093-1107, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30927084

RESUMO

The presence of articulated laticifers in the Moraceae family was recently discovered, which means that the location of pectinase and cellulase activities must be of great importance for their growth. Thus, the present study aimed to determine the role of these enzymes in the laticifer growth in Ficus montana and Maclura tinctoria. Reproductive meristems were collected and fixed in Karnovsky. Pectinase and cellulase labeling was performed in part of the samples, while another part was processed for usual TEM analyses. Pectinase and cellulase activities were detected in the vacuole and close to the middle lamella in both species. The presence of cellulases in the laticifers supports their articulated origin. Therefore, the occurrence of pectinase and cellulase activity in the laticifers points out that these enzymes could act in the dissolution of the transverse walls and in the processes of intrusive growth (through the dissolution of the middle lamella) and cell elongation (through the partial disassembly of components of the wall making it more plastic). Both enzymes are synthesized in the endoplasmic reticulum and transported to the cell wall by exocytosis or stored in the vacuole. The species studied showed a diverse subcellular composition, which is probably related to the species and not to the laticifer type (they present the same type) and to the composition of the latex (they show similar latex composition). We conclude that the presence of pectinases and cellulases can be used as a diagnostic condition for the laticifer types (articulated vs. non-articulated).


Assuntos
Celulases/metabolismo , Ficus/metabolismo , Maclura/metabolismo , Poligalacturonase/metabolismo , Parede Celular/metabolismo , Parede Celular/ultraestrutura , Ficus/citologia , Látex/metabolismo , Maclura/citologia , Meristema/metabolismo , Microscopia Eletrônica de Transmissão , Células Vegetais/metabolismo , Células Vegetais/ultraestrutura , Vacúolos/metabolismo
20.
Physiol Plant ; 166(1): 105-119, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30834537

RESUMO

The maximum quantum yield of photosystem II (as reflected by variable to maximum chlorophyll a fluorescence, Fv /Fm ) is regarded as one of the most important photosynthetic parameters. The genetic basis underlying natural variation in Fv /Fm , which shows low level of variations in plants under non-stress conditions, is not easy to be exploited using the conventional gene cloning approaches. Thus, in order to answer this question, we have followed another strategy: we used genome-wide association study (GWAS) and transgenic analysis in a rice mini-core collection. We report here that four single-nucleotide polymorphisms, located in the promoter region of ß-glucosidase 5 (BGlu-5), are associated with observed variation in Fv /Fm . Indeed, our transgenic analysis showed a good correlation between BGlu-5 and Fv /Fm . Thus, our work demonstrates the feasibility of using GWAS to study natural variation in Fv /Fm , suggesting that cis-element polymorphism, affecting the BGlu-5 expression level, may, indirectly, contribute to Fv /Fm variation in rice through the gibberellin signaling pathway. Further research is needed to understand the mechanism of our novel observation.


Assuntos
Estudo de Associação Genômica Ampla/métodos , Glucosidases/metabolismo , Complexo de Proteína do Fotossistema II/metabolismo , Celulases/genética , Celulases/metabolismo , Giberelinas/metabolismo , Glucosidases/genética , Complexo de Proteína do Fotossistema II/genética , Polimorfismo de Nucleotídeo Único/genética
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