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Search Results: 1 - 10 of 12388 matches for " Eleni Gomes "
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Ribonuclease Production by Aspergillus species
Gomes, Eleni;Silva, Roberto da;Serzedello, Alcides;
Revista de Microbiologia , 1998, DOI: 10.1590/S0001-37141998000300008
Abstract: ribonuclease production by aspergillus flavipes, a. sulphureus and a. fischeri in semi-synthetic medium, after 24-144 hours at 30oc under shaking, was studied. after cultivation, the medium was separated from micelia by filtration and the resultant solution was used as enzymatic extract. the highest amount of biomass and rnase was obtained after 96 hours of cultivation. the enzymes produced by three species presented similar characteristics, with optimum temperature at 55oc and two peaks of activity at ph 4.5 and 7.0. a. flavipes rnases were more sensitive to temperature: 50% of the initial activity was lost after 1 hour at 70oc. after this heat treatment, rnase of a. sulphureus lost 30% of this activity and that of a. fischeri only 16%. the nucleotides released by enzimatic hydrolysis of rna were separated by ion exchange chromatography in a ag-1x8-formiate column and identified by paper chromatography. this procedure indicated that the raw enzymatic extract of aspergillus flavipes is able to hydrolyze rna, releasing 3'-nucleotides monophosphate at ph 4.5 and 3' and 5'-nucleotides monophosphate at ph 7.0 and 8.5. this result suggests that this strain produces two different types of rnase, one acidic and other alcaline, with different specificities.
Ribonuclease Production by Aspergillus species
Gomes Eleni,Silva Roberto da,Serzedello Alcides
Revista de Microbiologia , 1998,
Abstract: Ribonuclease production by Aspergillus flavipes, A. sulphureus and A. fischeri in semi-synthetic medium, after 24-144 hours at 30oC under shaking, was studied. After cultivation, the medium was separated from micelia by filtration and the resultant solution was used as enzymatic extract. The highest amount of biomass and RNase was obtained after 96 hours of cultivation. The enzymes produced by three species presented similar characteristics, with optimum temperature at 55oC and two peaks of activity at pH 4.5 and 7.0. A. flavipes RNases were more sensitive to temperature: 50% of the initial activity was lost after 1 hour at 70oC. After this heat treatment, RNase of A. sulphureus lost 30% of this activity and that of A. fischeri only 16%. The nucleotides released by enzimatic hydrolysis of RNA were separated by ion exchange chromatography in a AG-1X8-formiate column and identified by paper chromatography. This procedure indicated that the raw enzymatic extract of Aspergillus flavipes is able to hydrolyze RNA, releasing 3'-nucleotides monophosphate at pH 4.5 and 3' and 5'-nucleotides monophosphate at pH 7.0 and 8.5. This result suggests that this strain produces two different types of RNase, one acidic and other alcaline, with different specificities.
Production of Pectate Lyase by Penicillium viridicatum RFC3 in Solid-State and Submerged Fermentation
Viviani Ferreira,Roberto da Silva,Dênis Silva,Eleni Gomes
International Journal of Microbiology , 2010, DOI: 10.1155/2010/276590
Abstract: Pectate lyase (PL) was produced by the filamentous fungus Penicillium viridicatum RFC3 in solid-state cultures of a mixture of orange bagasse and wheat bran (1 : 1 w/w), or orange bagasse, wheat bran and sugarcane bagasse (1 : 1 : 0.5 w/w), and in a submerged liquid culture with orange bagasse and wheat bran (3%) as the carbon source. PL production was highest (1,500 U  mL?1 or 300 Ug?1 of substrate) in solid-state fermentation (SSF) on wheat bran and orange bagasse at 96 hours. PL production in submerged fermentation (SmF) was influenced by the initial pH of the medium. With the initial pH adjusted to 4.5, 5.0, and 5.5, the peak activity was observed after 72, 48, and 24 hours of fermentation, respectively, when the pH of the medium reached the value 5.0. PL from SSF and SmF were loaded on Sephadex-G75 columns and six activity peaks were obtained from crude enzyme from SSF and designated PL I, II, III, IV, V, and VI, while five peaks were obtained from crude enzyme from SmF and labeled PLI, II, III, IV, and VII. Crude enzyme and fraction III from each fermentative process were tested further. The optimum pH for crude PL from either process was 5.5, while that for PL III was 8.0. The maximum activity of enzymes from SSF was observed at 35°C, but crude enzyme was more thermotolerant than PL III, maintaining its maximum activity up to 45°C. Crude enzyme from SmF and PL III showed thermophilic profiles of activity, with maximum activity at 60 and 55°C, respectively. In the absence of substrate, the crude enzyme from SSF was stable over the pH range 3.0–10.0 and PL III was most stable in the pH range 4.0–7.0. Crude enzyme from SmF retained 70%–80% of its maximum activity in the acid-neutral pH range (4.0–7.0), but PIII showed high stability at alkaline pH (7.5–9.5). PL from SSF was more thermolabile than that from SmF. The latter maintained 60% of its initial activity after 1 h at 55°C. The differing behavior of the enzymes with respect to pH and temperature suggests that they are different isozymes.
Production and characterization of glucoamylase from fungus Aspergillus awamori expressed in yeast Saccharomyces cerevisiae using different carbon sources
Pavezzi, Fabiana Carina;Gomes, Eleni;Silva, Roberto da;
Brazilian Journal of Microbiology , 2008, DOI: 10.1590/S1517-83822008000100024
Abstract: glucoamylase is widely used in the food industry to produce high glucose syrup, and also in fermentation processes for production beer and ethanol. in this work the productivity of the glucoamylase of aspergillus awamori expressed by the yeast saccharomyces cerevisiae, produced in submerged fermentation using different starches, was evaluated and characterized physico-chemically. the enzyme presented high specific activity, 13.8 u/mgprotein or 2.9 u/mgbiomass, after 48 h of fermentation using soluble starch as substrate. glucoamylase presented optimum activity at temperature of 55oc, and, in the substratum absence, the thermostability was for 1h at 50oc. the optimum ph of activity was ph 3.5 - 4.0 and the ph stability between 5.0 and 7.0. the half life at 65oc was at 30.2 min, and the thermal energy of denaturation was 234.3 kj mol-1. the hydrolysis of different substrate showed the enzyme's preference for the substrate with a larger polymerization degree. the gelatinized corn starch was the substratum most susceptible to the enzymatic action.
Produ??o de geléia de jambol?o (Syzygium cumini Lamarck): processamento, parametros físico - químicos e avalia??o sensorial
Lago, Ellen Silva;Gomes, Eleni;Silva, Roberto da;
Ciência e Tecnologia de Alimentos , 2006, DOI: 10.1590/S0101-20612006000400021
Abstract: jambolan (syzygium cumini lamarck) is a purple colored and very tasty fruit. since there are no reports of its industrial use, the production of this jelly has become a matter of interest for research. the purpose of this work is to develop and evaluate the physical-chemical and sensory characteristics of the jelly made of jambolan. the fruit showed the following chemical composition: ash, 0.34%; lipids, 0.30%; proteins, 0.67%; carbohydrates, 10.07%; fibers, 0.28%; moisture, 87.75%; fructose, 0.4%; glucose, 0.6%; total anthocyanins, 0.276%; pectic substances, 0.245%; acidity (direct titration), 5.91%; soluble solids, 9.00% and ph 3.9. the jelly showed the following composition: reducing sugars, 20.99%; non-reducing, 18.01%; total sugars, 39.00%; ph, 3.42; soluble solids, 67 °brix; acidity (direct titration), 5.47% and moisture, 29.63%. the sensory analysis was made by a non-trained-50 member panel who evaluated the color of the attributes, appearance, aroma, texture, taste and overall evaluation on a 9-point hedonic scale. the results showed that color was the most appreciated attribute while aroma was the least appreciated. in conclusion, the sensory analysis study revealed satisfactory acceptance of jambolan jelly.
Poliporóides (Basidiomycota) em fragmentos de mata no perímetro urbano de S?o José do Rio Preto, S?o Paulo, Brasil
Abrah?o, Maira Cortellini;Gugliotta, Adriana De Mello;Gomes, Eleni;
Brazilian Journal of Botany , 2009, DOI: 10.1590/S0100-84042009000300004
Abstract: a survey of polyporoid fungi from forest fragments of s?o josé do rio preto urban perimeter (20°49'12" s, 49°22'44" w), s?o paulo state, brazil was carried out. eighteen taxa belonging to 11 genera of agaricales (schizophyllaceae), hymenochaetales (hymenochaetaceae) and polyporales (ganodermataceae, gloeophyllaceae, meruliaceae and polyporaceae) were identified: coriolopsis floccosa (jungh.) ryvarden, c. polyzona (pers.) ryvarden, datronia caperata (berk.) ryvarden, d. mollis (somf.:fr.) donk., ganoderma australe (fr.) pat., gloeophyllum striatum (sw.) murrill, gloeoporus thelephoroides (hook.) g. cunn., hexagonia hirta (p. beauv.) fr., h. hydnoides (sw.) m. fidalgo, h. papyracea berk., polyporus tenuiculus (p. beauv.) fr., phellinus callimorphus (lév.) ryvarden, p. gilvus (schwein.) pat., p. umbrinellus (bres.) herrera & bondartseva, pycnoporus sanguineus (l.) murrill, schizophyllum commune fr., s. umbrinum berk. and trametes modesta (kunze:fr.) ryvarden. datronia mollis is a new record for s?o paulo state. identification key, descriptions and comments of the taxa studied are provided.
Production of Pectate Lyase by Penicillium viridicatum RFC3 in Solid-State and Submerged Fermentation
Viviani Ferreira,Roberto da Silva,Dênis Silva,Eleni Gomes
International Journal of Microbiology , 2010, DOI: 10.1155/2010/276590
Abstract: Pectate lyase (PL) was produced by the filamentous fungus Penicillium viridicatum RFC3 in solid-state cultures of a mixture of orange bagasse and wheat bran (1?:?1?w/w), or orange bagasse, wheat bran and sugarcane bagasse (1?:?1?:?0.5?w/w), and in a submerged liquid culture with orange bagasse and wheat bran (3%) as the carbon source. PL production was highest (1,500?U? or 300? of substrate) in solid-state fermentation (SSF) on wheat bran and orange bagasse at 96 hours. PL production in submerged fermentation (SmF) was influenced by the initial pH of the medium. With the initial pH adjusted to 4.5, 5.0, and 5.5, the peak activity was observed after 72, 48, and 24 hours of fermentation, respectively, when the pH of the medium reached the value 5.0. PL from SSF and SmF were loaded on Sephadex-G75 columns and six activity peaks were obtained from crude enzyme from SSF and designated PL I, II, III, IV, V, and VI, while five peaks were obtained from crude enzyme from SmF and labeled , , , , and . Crude enzyme and fraction III from each fermentative process were tested further. The optimum pH for crude PL from either process was 5.5, while that for PL III was 8.0. The maximum activity of enzymes from SSF was observed at , but crude enzyme was more thermotolerant than PL III, maintaining its maximum activity up to . Crude enzyme from SmF and PL showed thermophilic profiles of activity, with maximum activity at 60 and , respectively. In the absence of substrate, the crude enzyme from SSF was stable over the pH range 3.0–10.0 and PL III was most stable in the pH range 4.0–7.0. Crude enzyme from SmF retained 70%–80% of its maximum activity in the acid-neutral pH range (4.0–7.0), but PIII showed high stability at alkaline pH (7.5–9.5). PL from SSF was more thermolabile than that from SmF. The latter maintained 60% of its initial activity after 1?h at . The differing behavior of the enzymes with respect to pH and temperature suggests that they are different isozymes. 1. Introduction The pectinolytic enzyme group includes protopectinases that degrade insoluble pectin, esterases that catalyse the de-esterification of pectin by removing the methoxyl esters groups and depolymerases that cleave - ( -) glycosidic bonds by hydrolysis and transelimination mechanisms. The lyases break down the glycosidic bonds of the pectates or pectins at C-4 and eliminate H from C-5, releasing a 4,5-unsaturated product [1]. These enzymes belong to various classes: pectate disaccharide lyase (exopectate lyase—ExoPGL) E.C. 4.2.2.9, pectin lyase (Endo-pectin lyase—EndoPMGL) E.C. 4.2.2.10,
Partial purification, immobilization and preliminary biochemical characterization of lipases from Rhizomucor pusillus  [PDF]
Ana Lúcia Ferrarezi, Daniele H. Pivetta, Gustavo Orlando Bonilla-Rodriguez, Roberto da Silva, José Manuel Guisan, Eleni Gomes, Benevides Costa Pessela
Advances in Enzyme Research (AER) , 2013, DOI: 10.4236/aer.2013.14009
Abstract: Lipases have important applications in biotechnological processes, motivating us to produce, purify, immobilize and perform a biochemical characterization of the lipase from Rhizomucor pusillus. The fungus was cultivated by solid state fermentation producing lipolytic activity of about 0.5 U/mL(4U/g). A partial purification by gel filtration chromatography in Se-phacryl S-100 allowed obtaining a yield of about 85% and a purification factor of 5.7. Our results revealed that the purified enzyme is very stable with some significant differences in its properties when compared to crude extract. The crude enzyme extract has an optimum pH and temperature of 7.5 ° C and 40 ° C, respectively. After purification, a shift of the optimum pH from 7 to 8 was observed, as well as a rise in optimumtemperature to 60 ° C and an increase in stability. The enzyme was immobilized on CNBr-Agarose and Octyl-Agarose supports, having the highest immobilization yield of 94% in the second resin. The major advantage of immobilization in hydrophobic media such as Octyl is in its hyper activation, which in this case was over 200%, a very interesting finding. Another advantage of this type of immobilization is the possibility of using the derivatives in biotechnological applications, such as in oil enriched with omega-3 as the results obtained in this study display the hydrolysis of 40% EPA and 7% DHA from sardine oil, promising results compared to the literature.
Effect of Storage Conditions on the Sensory Quality, Colour and Texture of Fresh-Cut Minimally Processed Cabbage with the Addition of Ascorbic Acid, Citric Acid and Calcium Chloride  [PDF]
Eleni Manolopoulou, Theodoros Varzakas
Food and Nutrition Sciences (FNS) , 2011, DOI: 10.4236/fns.2011.29130
Abstract: The aim of this study was to investigate the effect of storage conditions on the sensory quality, colour and texture of fresh-cut cabbage during the addition of ascorbic acid, citric acid and calcium chloride. Ascorbic acid maintained the overall quality for 14 days at 0℃ and 7 days at 5℃; no difference, however, was observed regarding browning of cut surface compared to the control sample at both storage temperatures. Calcium chloride maintained the overall quality and cut surface browning for 14 days at both storage temperatures. It was also found that citric acid 1% can be used for minimally processed cabbage. Soaking with citric acid helped retain the color and increased the overall acceptance and organoleptic quality of fresh cut cabbage; it reduced browning of the cut surface and protected against formation of black specks. Citric acid treatment combined with low temperature storage (0℃) prolonged the shelf life of minimally processed cabbage for 22 days, time sufficient for acceptable marketing of the product. The lightness of minimally processed cabbage decreased linearly from 70.94 ± 6 to 63.8 ± 8.5 - 61.3 ± 8 units for the chemical treatments during 22 days of storage at 0℃. Hue angle values during storage time were also significantly influenced by chemical treatments mainly at 0℃.
School Effects on Adolescent Substance Use: Prevention through Interactive and Social Learning Strategies  [PDF]
Eleni Stefanidi, George Tsitsas
Creative Education (CE) , 2015, DOI: 10.4236/ce.2015.65050
Abstract: This study aimed to examine: a) the factors in Greek schools that are related to the school course of the adolescent drug abusers; b) the effectiveness of new interactive and social learning strategies in preventing drug use. Data were drawn from a face-to-face survey carried out on population of ex-drug abusers that were attending therapeutic programs of STROFI-KETHEA and in other places such as private with psychiatrists. The sample was 22 boys and 8 girls aged 16 to 21 years. All participants had a drug use experience and high rates of school drop out. The results suggest that factors related to the Greek school environment-meaning its culture, sense of community, education strategies–have negatively affected the school course of the participants. The poor school connectedness and dropping out effect negatively on young people’s behavior and drug use problems. Prevention should be considered through a new approach of the education system.
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