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| Registros recuperados: 54 | |
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| Slivinski,Christiane Trevisan; Machado,Alex Vinicius Lopes; Iulek,Jorge; Ayub,Ricardo Antônio; Almeida,Mareci Mendes de. |
| In this work, glucoamylase was produced by Aspergillus niger in solid-state fermentation. The enzyme was partially purified by ammonium sulphate precipitation and ion exchange and gel filtration chromatographies. Its molecular mass was estimated as 118.17 kDa by electrophoresis. The partially purified enzyme had an optimum pH range of 4.5-5.0 and an optimum temperature of 60 °C, with average activity 152.85 U mL-1. Thermal and pH stability assays with the crude extract showed that more than 60 % of the activity remained at pH 4.6 and 60 °C, even after an exposition to these conditions longer than 24 h. Yet, after purification, the enzyme was stable at these for at least 4 h, which indicated that its purification for use in starch saccharification was... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Glucoamylase; Aspergillus niger; Solid-state fermentation; Biochemical characterization; Purification. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132011000300018 |
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| Jin,Wei; Nie,Guangjun; Liu,Hui; Xiaoran,Yang; Gong,Guohong; Wang,Li; Zheng,Zhiming. |
| This work aimed to improve tannase yield of Aspergillus niger through N+ ion beam implantation in submerged fermentation. The energy and dose of N+ ion beam implantation were investigated. The results indicated that an excellent mutant was obtained through nine successive implantations under the conditions of 10 keV and 30-40 (×2.6×10(13)) ions/cm², and its tannase yield reached 38.5 U/mL, which was about five-time higher than the original strain. The study on the genetic stability of the mutant showed that its promising performance in tannase production could be stable. The studies of metal ions and surfactants affecting tannase yield indicated that manganese ions, stannum ions, xylene and SDS contained in the culture medium had positive effects on... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Aspergillus niger; N+ ion implantation; Tannase. |
| Ano: 2013 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132013000100018 |
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| Martos,María A.; Martinez Vazquez,Francisco; Benassi,Fernando O.; Hours,Roque A.. |
| Response surface methodology was used for optimization of polygalacturonase (PG) and pectinesterase (PE) production in submerged fermentation by A.niger. A Central Composite Experimental Design was applied, consisting of 22 experiments, including eight central points. Variables studied were: fermentation time (24 to 120 h), pH (3.5 to 6.5) and initial concentration of pectin (5 to 20 g/l). Maximum PE production was 220 U/l, after 74 h of culture, in a medium containing 20 g/l of pectin (pH 6.5). The optimal conditions for PG production were pH: 4.1, 20 g/l of pectin and 94 h of fermentation with a maximum value of 1032 U/l. Under these conditions, the PE production was low (15 U/l). A liquid extract with high PG activity and low PE activity could be... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Pectinases; Polygalacturonase; Pectinesterase; Aspergillus niger; Response surface methodology; Citrus pectin. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132009000300007 |
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| Vandenberghe,Luciana P. S; Soccol,Carlos R; Pandey,Ashok; Lebeault,Jean-Michel. |
| Citric acid is the most important organic acid produced in tonnage and is extensively used in food and pharmaceutical industries. It is produced mainly by submerged fermentation using Aspergillus niger or Candida sp. from different sources of carbohydrates, such as molasses and starch based media. However, other fermentation techniques, e.g. solid state fermentation and surface fermentation, and alternative sources of carbon such as agro-industrial residues have been intensively studied showing great perspective to its production. This paper reviews recent developments on citric acid production by presenting a brief summary of the subject, describing micro-organisms, production techniques, and substrates, etc. |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Citric acid; Aspergillus niger; Submerged fermentation; Solid state fermentation; Substrates. |
| Ano: 1999 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89131999000300001 |
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| Cruz,Vinícius D'Arcadia; Belote,Juliana Gisele; Dorta,Claudia; Santos,Luíza Helena Oliveira dos; Andriolo,Cláudia Regina; Khenayfes,Marcelo de Oliveira; Cruz,Rubens. |
| Aspergillus niger - 245, a strain isolated from soil samples showed good β-fructosidase activity when inoculated in medium formulated with dahlia extract tubers. The enzyme was purified by precipitation in ammonium sulphate and percolated in DEAE-Sephadex A-50 and CM-cellulose columns, witch showed a single peack in all the purification steps, maintaining the I/S ratio between 0.32 to, 0.39. Optimum pH for inulinase activity (I) was between 4.0 - 4.5 and for invertase activity (S) between 2.5 and 5.0. The optimum temperature was 60O.C for both activities and no loss in activity was observed when it was maintained at this temperature for 30 min. The Km value was 1.44 and 5.0, respectively, for I and S and Vm value 10.48 and 30.55, respectively. The I... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Inulinase; Invertase; Β-fructosidase; Inulin; Fructose syrup; Aspergillus niger. |
| Ano: 1998 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89131998000300003 |
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| Srivastava,Anita; Kar,Rita. |
| Extracellular tannase and gallic acid were produced optimally under submerged fermentation at 37 0C, 72 h, pH 5.0, 10 %(v/v) inoculum and 4 %(w/v) of the agroresidue pomegranate rind (PR) powder by an Aspergillus niger isolate. Tannic acid (1 %) stimulated the enzyme production by 245.9 % while with 0.5 % glucose, increase was marginal. Tannase production was inhibited by gallic acid and nitrogen sources such as NH4NO3, NH4Cl, KNO3, asparatic acid, urea and EDTA. The partially purified enzyme showed temperature and pH optima of 35 0C and 6.2 respectively which shifted to 40 0C and 5.8 on immobilization in alginate beads. Activity of the enzyme was inhibited by Zn+2, Ca+, Mn+2, Mg+2, Ba+2and Ag+. The immobilized enzyme removed 68.8 % tannin from juice of... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Tannase; Pomegranate rind; Myrobalan; Aspergillus niger. |
| Ano: 2009 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822009000400008 |
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| Goulart,Rosangela de Carvalho; Marin,José Moacir. |
| Some filamentous fungi present the phenomenon of dimorphism, their morphological structure alterations being capable of inducing metabolism changes. The Aspergillus niger strain 10v10, a producer of citric acid, was submitted to the mutagenic action of ultraviolet irradiation which respectively selects mutants sensitive or resistant to the antifungi agent 5 fluorocytosine (5-FC). 5-FC sensitive mutants presented a morphological alteration to a yeast-like form. The effects of pH changes, addition of salts (KH2PO4, NH4NO3, MgSO4 and MgCl2), the presence of osmotic stabilizers, as well as of calcium chloride, on morphological reversal and acid production were studied. Morphological reversal to the filamentous form was observed only in the presence of CaCl2... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Aspergillus niger; 5-fluorocytosine; Yeast-like; Calcium; Acid production; Dimorphism. |
| Ano: 2005 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822005000300018 |
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| Kanan,Ghassan J. M.; Al-Najjar,Heyam E.. |
| We aimed her mainly to evaluate the contribution of newly employed bromate selection system, in obtaining new Aspergillus niger nitrate/nitrite assimilation defective mutants, through Ultraviolet treatment (UV), 1, 2, 7, 8-Diepoxyoctane (DEO), phenols mixture (Phx)) and spontaneous treatments. The newly employed bromate selection system was able to specify only two putative novel mutant types designated brn (bromate resistant but chlorate sensitive (RS) strain, which may specify nitrite specific transporter) and cbrn mutants (bromate resistant and chlorate resistant strain, which may specify nitrate/nitrite bispecific system). The most relevant and innovative findings of this research work involve the isolation of the RR (cbrn) mutants (a new type of... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Aspergillus niger; Chlorate; Bromate; Mutagenesis. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822010000400032 |
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| Dobrev,Georgi Todorov; Zhekova,Boriana Yordanova. |
| An extracellular endoglucanase was isolated from the culture liquid of xylanase producing strain Aspergillus niger B03. The enzyme was purified to a homogenous form, using consecutive ultrafiltration, anion exchange chromatography, and gel filtration. Endoglucanase was a monomer protein with a molecular weight of 26,900 Da determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and 28,800 Da determined by gel filtration. The optimal pH and temperature values for the enzyme action were 3.5 and 65ºC respectively. Endoglucanase was stable at 40ºC, pH 3.0 for 210 min. The substrate specificity of the enzyme was determined with carboxymethyl cellulose, filter paper, and different glycosides. Endoglucanase displayed maximum activity in the case... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Endoglucanase; Purification; Characterization; Aspergillus niger; Endoxylanase. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822012000100008 |
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| Gajera,H. P.; Vakharia,D. N. |
| Twelve isolates of Trichoderma (six of T. harzianum, five of T. viride, one of T. virens), which reduced variably the incidence of collar rot disease caused in peanut by Aspergillus niger Van Tieghem, were evaluated for their potential to produce lytic enzymes during in vitro antagonism. T. viride 60 inhibited highest (86.2%) growth of test fungus followed by T. harzianum 2J (80.4%) at 6 days after inoculation (DAI) on PDA media. The specific activities of chitinase, β-1,3-glucanase and protease were 11, 3.46 and 9 folds higher in T6 antagonist (T. viride 60 and A. niger interactions) followed by 8.72, 2.85 and 9 folds in T8 antagonist (T. harzianum 2J and A. niger interactions), respectively, compared to the activity produced by control petri plate T13... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Trichoderma isolates; Aspergillus niger; Lytic enzymes; Antagonistic interaction. |
| Ano: 2012 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822012000100005 |
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| Registros recuperados: 54 | |
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