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Pesquisa : G02.111.835 [Categoria DeCS]
Referências encontradas : 73 [refinar]
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Id: biblio-886801
Autor: MARCO, ÉVILIN G DE; HECK, KARINA; MARTOS, EMERSON T; VAN DER SAND, SUELI T.
Título: Purification and characterization of a thermostable alkaline cellulase produced by Bacillus licheniformis 380 isolated from compost
Fonte: An. acad. bras. ciênc;89(3,supl):2359-2370, 2017. tab, graf.
Idioma: en.
Resumo: ABSTRACT During composting processes, the degradation of organic waste is accomplished and driven by a succession of microbial populations exhibiting a broad range of functional competencies. A total of 183 bacteria, isolated from a composting process, were evaluated for cellulase activity at different temperatures (37, 50, 60, and 70°C) and pH values. Out of the 22 isolates that showed activity, isolate 380 showed the highest cellulase activity. Its ability to produce cellulase was evaluated in culture medium supplemented with carboxymethyl cellulose, microcrystalline cellulose, wheat straw, and rice husk. The culture medium supplemented with carboxymethyl cellulose induced higher enzyme activity after 6 hours of incubation (0.12 UEA mL-1 min-1). For wheat straw and rice husk, the results were 0.08 UEA mL-1 min-1 for both, while for microcrystalline cellulose, 0.04 UEA mL-1 min-1 were observed. The highest carboxymethyl cellulase activity was observed at 60°C (0.14 UEA mL-1 min-1) for both crude and partially purified enzyme after 30 and 120 min of incubation, respectively. Alkalinization of the medium was observed during cultivation in all substrates. The cellulase had a molecular mass of 20 kDa determined by SDS-Page. Isolate 380 was identified as Bacillus licheniformis. This work provides a basis for further studies on composting optimization.
Descritores: Carboximetilcelulose Sódica/farmacologia
Celulase/isolamento & purificação
Celulase/biossíntese
Meios de Cultura/farmacologia
Bacillus licheniformis/enzimologia
-Especificidade por Substrato
Eletroforese em Gel de Poliacrilamida
Bacillus licheniformis/efeitos dos fármacos
Temperatura Alta
Responsável: BR1.1 - BIREME


  2 / 73 LILACS  
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Id: biblio-886937
Autor: MARQUES NETTO, CATERINA G C; PALMEIRA, DAYVSON J; BRONDANI, PATRÍCIA B; ANDRADE, LEANDRO H.
Título: Enzymatic reactions involving the heteroatoms from organic substrates
Fonte: An. acad. bras. ciênc;90(1,supl.1):943-992, 2018. tab, graf.
Idioma: en.
Resumo: ABSTRACT Several enzymatic reactions of heteroatom-containing compounds have been explored as unnatural substrates. Considerable advances related to the search for efficient enzymatic systems able to support a broader substrate scope with high catalytic performance are described in the literature. These reports include mainly native and mutated enzymes and whole cells biocatalysis. Herein, we describe the historical background along with the progress of biocatalyzed reactions involving the heteroatom(S, Se, B, P and Si) from hetero-organic substrates.
Descritores: Bactérias/metabolismo
Biotransformação
Enzimas/metabolismo
Biocatálise
Fungos/metabolismo
-Especificidade por Substrato
Técnicas Biossensoriais
Enzimas/química
Tipo de Publ: Revisão
Responsável: BR1.1 - BIREME


  3 / 73 LILACS  
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Lebrun, I
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Id: lil-303314
Autor: Anéas, M. A. F; Portaro, F. C. V; Lebrun, I; Juliano, L; Palma, M. S; Fernandes, B. L.
Título: ZapA, a possible virulence factor from Proteus mirabilis exhibits broad protease substrate specificity
Fonte: Braz. j. med. biol. res = Rev. bras. pesqui. méd. biol;34(11):1397-1403, Nov. 2001. ilus, tab.
Idioma: en.
Resumo: The opportunistic bacterium Proteus mirabilis secretes a metalloprotease, ZapA, considered to be one of its virulence factors due to its IgA-degrading activity. However, the substrate specificity of this enzyme has not yet been fully characterized. In the present study we used fluorescent peptides derived from bioactive peptides and the oxidized ß-chain of insulin to determine the enzyme specificity. The bradykinin- and dynorphin-derived peptides were cleaved at the single bonds Phe-Ser and Phe-Leu, with catalytic efficiencies of 291 and 13 mM/s, respectively. Besides confirming already published cleavage sites, a novel cleavage site was determined for the ß-chain of insulin (Val-Asn). Both the natural and the recombinant enzyme displayed the same broad specificity, demonstrated by the presence of hydrophobic, hydrophilic, charged and uncharged amino acid residues at the scissile bonds. Native IgA, however, was resistant to hydrolysis by ZapA
Descritores: Proteus mirabilis
Metaloendopeptidases
Proteínas de Bactérias
-Proteus mirabilis
Espectrometria de Massas
Especificidade por Substrato
Virulência
Metaloendopeptidases
Hidrólise
Proteínas de Bactérias/análise
Responsável: BR1.1 - BIREME


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Lebrun, I
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Id: lil-262675
Autor: Fernandes, B. L; Anéas, M. A. F; Juliano, L; Palma, M. S; Lebrun, I; Portaro, F. C. V.
Título: Development of an operational substrate for ZapA, a metalloprotease secreted by the bacterium Proteus mirabilis
Fonte: Braz. j. med. biol. res = Rev. bras. pesqui. méd. biol;33(7):765-70, July 2000. tab, graf.
Idioma: en.
Resumo: The protease ZapA, secreted by Proteus mirabilis, has been considered to be a virulence factor of this opportunistic bacterium. The control of its expression requires the use of an appropriate methodology, which until now has not been developed. The present study focused on the replacement of azocasein with fluorogenic substrates, and on the definition of enzyme specificity. Eight fluorogenic substrates were tested, and the peptide Abz-Ala-Phe-Arg-Ser-Ala-Ala-Gln-EDDnp was found to be the most convenient for use as an operational substrate for ZapA. A single peptide bond (Arg-Ser) was cleaved with a Km of 4.6 µM, a k cat of 1.73 s-1, and a catalytic efficiency of 376 (mM s)-1. Another good substrate for ZapA was peptide 6 (Abz-Arg-Pro-Pro-Gly-Phe-Ser-Pro-Phe-Arg-Gln-EDDnp) which was cleaved at a single bond (Phe-Ser) with a Km of 13.6 µM, a k cat of 3.96 s-1 and a catalytic efficiency of 291 (mM s)-1. The properties of the amino acids flanking the scissile bonds were also evaluated, and no clear requirement for the amino acid residue at P1 was found, although the enzyme seems to have a preference for a hydrophobic residue at P2.
Descritores: Peptídeos/análise
Proteus mirabilis/enzimologia
Proteínas de Bactérias
Metaloendopeptidases
-Endopeptidases/isolamento & purificação
Infecções por Proteus/microbiologia
Proteus mirabilis/genética
Proteus mirabilis/patogenicidade
Espectrometria de Fluorescência
Espectrometria de Massas
Especificidade por Substrato
Proteínas de Bactérias/análise
Metaloendopeptidases/análise
Cinética
Caseínas/análise
Hidrólise
Tipo de Publ: Research Support, Non-U.S. Gov't
Responsável: BR1.1 - BIREME


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Id: biblio-951810
Autor: Rungrattanakasin, Budsayachat; Premjet, Siripong; Thanonkeo, Sudarat; Klanrit, Preekamol; Thanonkeo, Pornthap.
Título: Cloning and expression of an endoglucanase gene from the thermotolerant fungus Aspergillus fumigatus DBiNU-1 in Kluyveromyces lactis
Fonte: Braz. j. microbiol;49(3):647-655, July-Sept. 2018. graf.
Idioma: en.
Resumo: Abstract An intronless endoglucanase from thermotolerant Aspergillus fumigatus DBINU-1 was cloned, characterized and expressed in the yeast Kluyveromyces lactis. The full-length open reading frame of the endoglucanase gene from A. fumigatus DBiNU-1, designated Cel7, was 1383 nucleotides in length and encoded a protein of 460 amino acid residues. The predicted molecular weight and the isoelectric point of the A. fumigatus Cel7 gene product were 48.19 kDa and 5.03, respectively. A catalytic domain in the N-terminal region and a fungal type cellulose-binding domain/module in the C-terminal region were detected in the predicted polypeptide sequences. Furthermore, a signal peptide with 20 amino acid residues at the N-terminus was also detected in the deduced amino acid sequences of the endoglucanase from A. fumigatus DBiNU-1. The endoglucanase from A. fumigatus DBiNU-1 was successfully expressed in K. lactis, and the purified recombinant enzyme exhibited its maximum activity at pH 5.0 and 60 °C. The enzyme was very stable in a pH range from 4.0 to 8.0 and a temperature range from 30 to 60 °C. These features make it suitable for application in the paper, biofuel, and other chemical production industries that use cellulosic materials.
Descritores: Aspergillus fumigatus/enzimologia
Proteínas Fúngicas/genética
Proteínas Fúngicas/química
Expressão Gênica
Celulase/genética
Celulase/química
Clonagem Molecular
-Aspergillus fumigatus/genética
Especificidade por Substrato
Estabilidade Enzimática
Kluyveromyces/genética
Kluyveromyces/metabolismo
Proteínas Recombinantes/genética
Proteínas Recombinantes/metabolismo
Proteínas Recombinantes/química
Proteínas Fúngicas/metabolismo
Celulase/metabolismo
Temperatura Alta
Concentração de Íons de Hidrogênio
Responsável: BR1.1 - BIREME


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Id: lil-788974
Autor: Gururaj, P; Ramalingam, Subramanian; Devi, Ganesan Nandhini; Gautam, Pennathur.
Título: Process optimization for production and purification of a thermostable, organic solvent tolerant lipase from Acinetobacter sp. AU07
Fonte: Braz. j. microbiol;47(3):647-657, July-Sept. 2016. tab, graf.
Idioma: en.
Projeto: Department of Biotechnology, Government of India.
Resumo: ABSTRACT The purpose of this study was to isolate, purify and optimize the production conditions of an organic solvent tolerant and thermostable lipase from Acinetobacter sp. AU07 isolated from distillery waste. The lipase production was optimized by response surface methodology, and a maximum production of 14.5 U/mL was observed at 30 ºC and pH 7, using a 0.5% (v/v) inoculum, 2% (v/v) castor oil (inducer), and agitation 150 rpm. The optimized conditions from the shake flask experiments were validated in a 3 L lab scale bioreactor, and the lipase production increased to 48 U/mL. The enzyme was purified by ammonium sulfate precipitation and ion exchange chromatography and the overall yield was 36%. SDS-PAGE indicated a molecular weight of 45 kDa for the purified protein, and Matrix assisted laser desorption/ionization time of flight analysis of the purified lipase showed sequence similarity with GDSL family of lipases. The optimum temperature and pH for activity of the enzyme was found to be 50 ºC and 8.0, respectively. The lipase was completely inhibited by phenylmethylsulfonyl fluoride but minimal inhibition was observed when incubated with ethylenediaminetetraacetic acid and dithiothreitol. The enzyme was stable in the presence of non-polar hydrophobic solvents. Detergents like SDS inhibited enzyme activity; however, there was minimal loss of enzyme activity when incubated with hydrogen peroxide, Tween 80 and Triton X-100. The kinetic constants (Km and Vmax) revealed that the hydrolytic activity of the lipase was specific to moderate chain fatty acid esters. The Vmax, Km and Vmax/Km ratio of the enzyme were 16.98 U/mg, 0.51 mM, and 33.29, respectively when 4-nitrophenyl palmitate was used as a substrate.
Descritores: Compostos Orgânicos
Solventes
Proteínas de Bactérias/isolamento & purificação
Proteínas de Bactérias/biossíntese
Acinetobacter/enzimologia
Lipase/isolamento & purificação
Lipase/biossíntese
-Compostos Orgânicos/química
Solventes/química
Especificidade por Substrato
Temperatura
Proteínas de Bactérias/química
Estabilidade Enzimática
Cinética
Cromatografia por Troca Iônica
Ativação Enzimática
Espaço Extracelular/enzimologia
Concentração de Íons de Hidrogênio
Íons
Lipase/química
Lipólise
Metais
Peso Molecular
Responsável: BR1.1 - BIREME


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Id: lil-788964
Autor: Corrêa, Juliana Moço; Christi, Divair; Torre, Carla Lieko Della; Henn, Caroline; Conceição-Silva, José Luis da; Kadowaki, Marina Kimiko; Simão, Rita de Cássia Garcia.
Título: High levels of ß-xylosidase in Thermomyces lanuginosus: potential use for saccharification
Fonte: Braz. j. microbiol;47(3):680-690, July-Sept. 2016. tab, graf.
Idioma: en.
Projeto: CAPES; . Araucária Foundation; . National Council for Scientific and Technological Development.
Resumo: ABSTRACT A new strain of Thermomyces lanuginosus was isolated from the Atlantic Forest biome, and its β-xylosidases optimization in response to agro-industrial residues was performed. Using statistical approach as a strategy for optimization, the induction of β-xylosidases activity was evaluated in residual corn straw, and improved so that the optimum condition achieved high β-xylosidases activities 1003 U/mL. According our known, this study is the first to show so high levels of β-xylosidases activities induction. In addition, the application of an experimental design with this microorganism to induce β-xylosidases has not been reported until the present work. The optimal conditions for the crude enzyme extract were pH 5.5 and 60 °C showing better thermostability at 55 °C. The saccharification ability of β-xylosidase in the presence of hemicellulose obtained from corn straw raw and xylan from beechwood substrates showed a xylo-oligosaccharide to xylose conversion yield of 80 and 50%, respectively, at 50 °C. Our data strongly indicated that the β-xylosidases activities was not subjected to the effects of potential enzyme inhibitors often produced during fermentation process. These data suggest the application of this enzyme studied for saccharification of hemicellulose, an abundant residue in the American continents, thus providing an interesting alternative for future tests for energy production.
Descritores: Ascomicetos/enzimologia
Xilosidases/metabolismo
Fermentação
-Polissacarídeos/metabolismo
Polissacarídeos/química
Especificidade por Substrato
Temperatura
Xilose/metabolismo
Biomassa
Zea mays/química
Ativação Enzimática
Concentração de Íons de Hidrogênio
Hidrólise
Responsável: BR1.1 - BIREME


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Id: biblio-839339
Autor: Wanderley, Maria Carolina de Albuquerque; Duarte Neto, José Manoel Wanderley; Lima Filho, José Luiz de; Lima, Carolina de Albuquerque; Teixeira, José António Couto; Porto, Ana Lúcia Figueiredo.
Título: Collagenolytic enzymes produced by fungi: a systematic review
Fonte: Braz. j. microbiol;48(1):13-24, Jan.-Mar. 2017. tab, graf.
Idioma: en.
Resumo: Abstract Specific proteases capable of degrading native triple helical or denatured collagen have been required for many years and have a large spectrum of applications. There are few complete reports that fully uncover production, characterization and purification of fungi collagenases. In this review, authors searched through four scientific on line data bases using the following keywords (collagenolytic OR collagenase) AND (fungi OR fungus OR fungal) AND (production OR synthesis OR synthesize) AND (characterization). Scientific criteria were adopted in this review to classify found articles by score (from 0 to 10). After exclusion criteria, 21 articles were selected. None obtained the maximum of 10 points defined by the methodology, which indicates a deficiency in studies dealing simultaneously with production, characterization and purification of collagenase by fungi. Among microorganisms studied the non-pathogenic fungi Penicillium aurantiogriseum and Rhizoctonia solani stood out in volumetric and specific collagenase activity. The only article found that made sequencing of a true collagenase showed 100% homology with several metalloproteinases fungi. A clear gap in literature about collagenase production by fungi was verified, which prevents further development in the area and increases the need for further studies, particularly full characterization of fungal collagenases with high specificity to collagen.
Descritores: Colágeno/metabolismo
Colagenases/metabolismo
Fungos/metabolismo
-Especificidade por Substrato
Colágeno/química
Colagenases/isolamento & purificação
Colagenases/biossíntese
Colagenases/química
Meios de Cultura
Ativação Enzimática
Proteólise
Fungos/classificação
Responsável: BR1.1 - BIREME


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Id: biblio-1010283
Autor: Niu, Dandan; Tian, Xiaojing; Peace Mchunu, Nokuthula; Jia, Chao; Singh, Suren; Liu, Xiaoguang; Prior, Bernard A; Lu, Fuping.
Título: Biochemical characterization of three Aspergillus niger ß-galactosidases
Fonte: Electron. j. biotechnol;27:37-43, May. 2017. tab, ilus, graf.
Idioma: en.
Projeto: National Natural Science Foundation of China; . National Natural Science Foundation of Fujian Province, China; . Priming Scientific Research Foundation of Fuzhou University.
Resumo: Background: ß-Galactosidases catalyze both hydrolytic and transgalactosylation reactions and therefore have many applications in food, medical, and biotechnological fields. Aspergillus niger has been a main source of ß-galactosidase, but the properties of this enzyme are incompletely studied. Results: Three new ß-galactosidases belonging to glycosyl hydrolase family 35 from A. niger F0215 were cloned, expressed, and biochemically characterized. In addition to the known activity of LacA encoded by lacA, three putative ß-galactosidases, designated as LacB, LacC, and LacE encoded by the genes lacB, lacC, and lacE, respectively, were successfully cloned, sequenced, and expressed and secreted by Pichia pastoris. These three proteins and LacA have N-terminal signal sequences and are therefore predicted to be extracellular enzymes. They have the typical structure of fungal ß-galactosidases with defined hydrolytic and transgalactosylation activities on lactose. However, their activity properties differed. In particular, LacB and lacE displayed maximum hydrolytic activity at pH 4­5 and 50°C, while LacC exhibited maximum activity at pH 3.5 and 60°C. All ß-galactosidases performed transgalactosylation activity optimally in an acidic environment. Conclusions: Three new ß-galactosidases belonging to glycosyl hydrolase family 35 from A. niger F0215 were cloned and biochemically characterized. In addition to the known LacA, A. niger has at least three ß-galactosidase family members with remarkably different biochemical properties.
Descritores: Aspergillus niger/enzimologia
beta-Galactosidase/química
-Especificidade por Substrato
Cinética
Sequência de Aminoácidos
Clonagem Molecular
beta-Galactosidase/genética
beta-Galactosidase/metabolismo
Responsável: CL1.1 - Biblioteca Central


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Id: biblio-889226
Autor: Thomas, Lebin; Ram, Hari; Singh, Ved Pal.
Título: Inducible cellulase production from an organic solvent tolerant Bacillus sp. SV1 and evolutionary divergence of endoglucanase in different species of the genus Bacillus
Fonte: Braz. j. microbiol;49(2):429-442, Apr.-June 2018. tab, graf.
Idioma: en.
Resumo: Abstract Bacteria are important sources of cellulases with various industrial and biotechnological applications. In view of this, a non-hemolytic bacterial strain, tolerant to various environmental pollutants (heavy metals and organic solvents), showing high cellulolytic index (7.89) was isolated from cattle shed soil and identified as Bacillus sp. SV1 (99.27% pairwise similarity with Bacillus korlensis). Extracellular cellulases showed the presence of endoglucanase, total cellulase and β-glucosidase activities. Cellulase production was induced in presence of cellulose (3.3 times CMCase, 2.9 times FPase and 2.1 times β-glucosidase), and enhanced (115.1% CMCase) by low-cost corn steep solids. An in silico investigation of endoglucanase (EC 3.2.1.4) protein sequences of three Bacillus spp. as query, revealed their similarities with members of nine bacterial phyla and to Eukaryota (represented by Arthropoda and Nematoda), and also highlighted of a convergent and divergent evolution from other enzymes of different substrate [(1,3)-linked beta-d-glucans, xylan and chitosan] specificities. Characteristic conserved signature indels were observed among members of Actinobacteria (7 aa insert) and Firmicutes (9 aa insert) that served as a potential tool in support of their relatedness in phylogenetic trees.
Descritores: Bacillus/enzimologia
Celulase/genética
Celulase/metabolismo
Evolução Molecular
-Bacillus/crescimento & desenvolvimento
Bacillus/isolamento & purificação
Celulose/metabolismo
Biologia Computacional
Fezes/microbiologia
Regulação Bacteriana da Expressão Gênica
Regulação Enzimológica da Expressão Gênica
Mutação INDEL
Análise de Sequência de DNA
Homologia de Sequência
Especificidade por Substrato
Zea mays/metabolismo
Limites: Animais
Bovinos
Responsável: BR1.1 - BIREME



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