Sample records for immobilized enzymes
from WorldWideScience.org

Sample records 1 - 14 shown.



1

Imobilização de enzimas de milho maltado em gel/ Gel immobilization of enzymes from malted corn

Silva, Rosa Luísa de Farias Oliveira Bezerra e; Souza, Roberto Rodrigues de; Santana, José Carlos Curvelo; Tambourgi, Elias Basile
2008-09-01

Resumo em português Este trabalho objetivou a otimização da imobilização das enzimas amilases extraídas do malte do milho, usando alginato de sódio. A concentração do malte no extrato, a porcentagem de alginato de sódio e o pH foram usados como fatores que influenciam na imobilização das enzimas. Os resultados mostraram que as melhores condições de imobilização foram obtidas quando se usou as soluções de malte de milho em duas faixas de concentrações, uma entre 3,75 a 5 g. (mais) L-1 e outra entre 15 a 16,25 g.L-1, em pH entre 4,83 a 6,6 e 4% (m/v) de alginato de sódio, condições nas quais se conseguiu imobilizar 100% das enzimas com baixa perda de atividade. Este trabalho mostrou como se obter amilases de malte de milho imobilizadas por oclusão em alginato de sódio e que podem ser usadas em processos industriais de hidrólise de amido. Resumo em inglês This work aimed at optimizing the immobilization of amylases obtained from corn malt by the occlusion method with sodium alginate. Corn malt concentration, sodium alginate mass percentage and pH were used as factors that influence enzyme immobilization. The results showed that the best immobilization conditions were obtained at two ranges of corn malt concentration, one between 3.75-5 g.L-1 and the other between 15-16.25 g.L-1, at pH between 4.83-6.6 and at 4% (m/m) sodiu (mais) m alginate. In these conditions, 100% of the enzymes were immobilized with a low loss of activity. This work showed how to obtain immobilized corn malt amylases that can be used in industrial processes of starch hydrolysis by occlusion in sodium alginate.

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2

Estimulação elétrica neuromuscular em cães com atrofia muscular induzida/ Neuromuscular electric stimulation in dogs with induced muscle atrophy

Pelizzari, C.; Mazzanti, A.; Raiser, A.G.; Lopes, S.T.A.; Graça, D.L.; Ramos, A.T.; Salbego, F.Z.; Festugatto, R.; Beckmann, D.V.; Souza, L.B.; Cunha, M.G.M.C.M.; Santos, R.P.; Garmatz, B.; Silva, A.P.; Sturza, D.A.F.
2008-02-01

Resumo em português Empregou-se a estimulação elétrica neuromuscular (EENM) de baixa freqüência no músculo quadríceps femoral de cães com atrofia induzida e avaliou-se a ocorrência de ganho de massa nessa musculatura. Foram utilizados oito cães com pesos entre 15 e 30kg, distribuídos aleatoriamente em dois grupos denominados de I ou controle e II ou tratado. A articulação femorotibiopatelar esquerda foi imobilizada por 30 dias pelo método de transfixação percutânea tipo II, (mais) com retirada de aparelho de imobilização após esse período. Decorridas 48 horas da remoção, foi realizada a EENM nos cães do grupo II, cinco vezes por semana, com intervalo de 24 horas cada sessão, pelo período de 60 dias. Foram avaliadas a circunferência da coxa, a goniometria do joelho, a análise clínica da marcha, as enzimas creatina-quinase (CK) e aspartato-amino-transferase (AST) e a morfometria das fibras musculares em cortes transversais do músculo vasto lateral colhido mediante biópsia muscular. A EENM foi empregada no músculo quadríceps femoral na freqüência de 50Hz, duração de pulso de 300 milisegundos e relação de tempo on/off de 1:2. Quanto à morfometria das fibras do músculo vasto lateral, no grupo tratado houve aumento significativo (P Resumo em inglês Low frequency neuromuscular electrical stimulation (NMES) was used on the femoral quadriceps of dogs with induced muscular atrophy and the occurrence of gain in mass in these muscles was evaluated. Eight dogs from 15 to 30kg were randomly distributed in two groups named I, or control; and II, or treated. For the induction of muscular atrophy, the left femoral-tibial-patellar joint was immobilized for 30 days by percutaneous transfixation type II. After 30 days, the immobi (mais) lization device was removed. The NMES treatment began 48 hours after the removal of the immobilization device of the dogs of group II, and it was carried out five times per week with an interval of 24 hours between each session, for 60 days. The following parameters were measured: thigh circumference, goniometry of the knee, clinical gait analysis, creatine kinase (CK) and aspartate aminotransferase (AST) enzymes, and morphometry of the muscular fibers in transversal cuts of the vastus lateralis muscle collected through muscular biopsy. The NMES was applied on the femoral quadriceps at a frequency of 50 Hz, with pulse duration of 300 milliseconds, and the on/off time was at a proportion of 1:2. Regarding the morphometry of the vastus lateralis fibers, a significant increase (P

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3

Estimulação elétrica neuromuscular de média freqüência (russa) em cães com atrofia muscular induzida/ Medium frequency neuromuscular electrical stimulation (russian) in dogs with induced muscle atrophy

Pelizzari, Charles; Mazzanti, Alexandre; Raiser, Alceu Gaspar; Lopes, Sonia Terezinha dos Anjos; Graça, Dominguita Lühers; Salbego, Fabiano Zaninni; Ramos, Adriano Tony; Festugatto, Rafael; Beckmann, Diego Vilibaldo; Cunha, Marina Mori da; Santos, Rosmarini Passos dos; Cargnelutti, Juliana Filipeto; Pereira, Desydere Trindade; Martins, Tessie Beck
2008-06-01

Resumo em português A estimulação elétrica neuromuscular (EENM) de média freqüência (Russa) ou de Kotz pode ser empregada para a recuperação de massa muscular em animais apresentando atrofia muscular por desuso. Assim, o objetivo deste trabalho foi empregar a EENM de média freqüência no quadríceps femoral de cães com atrofia muscular induzida, avaliando-se a ocorrência de ganho de massa. Foram utilizados oito cães em dois grupos denominados de GI ou controle e de GII ou tratad (mais) o. Para a indução da atrofia muscular, a articulação fêmoro-tíbio-patelar esquerda foi imobilizada por 30 dias. Após 48 horas da remoção, foi realizada a EENM nos cães do grupo II, três vezes por semana, com intervalo de 48 horas cada sessão, pelo período de 60 dias. Foram avaliadas a mensuração da perimetria da coxa, da goniometria do joelho, as enzimas creatina-quinase (CK) e morfometria das fibras musculares em cortes transversais do músculo vasto lateral, colhido mediante a biópsia muscular. A EENM foi empregada no músculo quadríceps femoral numa freqüência de 2.500Hz, largura de pulso de 50% e relação de tempo on/off de 1:2. Não houve diferença significativa quanto aos valores de perimetria da coxa e a atividade da enzima CK entre os grupos I e II. Na goniometria, houve diminuição significativa (P Resumo em inglês The medium frequency neuromuscular electrical stimulation (NMES) (Russa) or Kotz is designed for recuperation of muscle mass in dogs with muscular atrophy in disuse. This study aims to utilize medium frequency NMES on the femoral quadriceps of dogs with induced muscular atrophy and evaluate the occurrence of gain in mass. Eight dogs in two groups denominated GI, or control, and GII, or treated were used. For the induction of muscular atrophy, the left femoral-tibial-patel (mais) lar joint was immobilized for 30 days. NMES treatment began 48 hours after the removal of the immobilization device on dogs from group II and was carried out three times per week, with an interval of 48 hours between each session, during 60 days. The following parameters were measured: thigh perimeter, goniometry of the knee, creatine kinase (CK) enzymes and morphometry of the muscular fibers in transversal cuts of the vastus lateralis muscle, collected through a muscular biopsy. EENM was utilized on the femoral quadriceps at a frequency of 2500 Hz, with pulse duration of 50%, and the time on/off was at a proportion of 1:2. There was no significant difference between the thigh perimeter and the activity of enzyme CK between groups I and II. As for the goniometry a significant increase (P

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4

Imobilização de lipases produzidas por fermentação em estado sólido utilizando Penicillium verrucosum em suportes hidrofóbicos/ Immobilization of lipases produced by solid state fermentation from Penicillium verrucosum on hydrophobic supports

Menoncin, Silvana; Domingues, Natalia Molossi; Freire, Denise Maria Guimarães; Oliveira, José Vladimir; Di Luccio, Marco; Treichel, Helen; Oliveira, Débora de
2009-06-01

Resumo em português O principal interesse em imobilizar uma enzima é obter um biocatalisador com atividade e estabilidade que não sejam afetadas durante o processo, em comparação à sua forma livre. Aliado ao potencial biotecnológico que as lipases apresentam, a aplicação destas em nível industrial requer a investigação de técnicas viáveis para reutilização e aumento da estabilidade, conferindo relevância aos processos de imobilização. Neste trabalho investigou-se a imobiliz (mais) ação da lipase produzida por fermentação em estado sólido utilizando Penicillium verrucosum em dois suportes hidrofóbicos; Accurel EP 1000 e Carvão Ativo. Para a imobilização das lipases foi adicionado 1 g de suporte a 50 mL de uma solução enzimática, estes permaneceram em contato por 2 horas em banho de gelo. Depois de decorrido este tempo, a solução foi filtrada e a enzima imobilizada colocada em dessecador por 48 horas e então feita a medida da atividade lipásica, proteína e cálculo da atividade específica. Através dos resultados obtidos, verificou-se que lipase imobilizada em carvão ativo apresentou valores de atividade específica superiores aos obtidos quando da utilização de Accurel EP 1000 como suporte. Utilizando carvão ativo como suporte, a atividade específica foi de 1533422,5 U/mg de proteína, rendimento de 30,4% e retenção de 382,5%. Resumo em inglês The major interest in the immobilization of enzymes is obtaining a biocatalyst with activity and stability that are not affected during the process when compared to the free enzyme. The application of lipases in industries requires the study of techniques suitable for reuse and stability increase such as immobilization strategies. This work studied the immobilization of lipases produced by solid state fermentation from Penicillium verrucosum using two hydrophobic supports (mais) : Accurel EP 1000 and activated carbon. For the lipase immobilization, 1 g of support was added to 50 mL of an enzyme solution and kept for 2 hour in an ice bath. The solution was then filtered and the immobilized enzyme was stored in a dissecator for 48 hour before the assays for lipase activity, protein, and specific lipase activity. The results showed that the lipase immobilized in activated carbon presented higher specific activity than the lipase immobilized in Accurel EP 1000. The use of activated carbon as support led to a specific activity of 1.5 × 10(6) U/mg of protein, yield of 30.42%, and retention of 382.516%.

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5

Síntese enzimática de butirato de isoamila empregando lipases microbianas comerciais/ Enzymatic synthesis isoamyl butyrate employing commercial microbial lipases

Aragão, Vitor Cardoso; Anschau, Andréia; Porciuncula, Barbara Daniele Almeida; Thiesen, Cleidi; Kalil, Susana Juliano; Burkert, Carlos André Veiga; Burkert, Janaína Fernandes de Medeiros
2009-01-01

Resumo em inglês Isoamyl butyrate production was investigated using free and immobilized lipases by esterification of butyric acid with isoamyl alcohol in a solvent-free system and in an organic media. Among the enzymes studied, Lipozyme TL IM was found to be the most active catalyst in n-hexane as a solvent. The effects of different solvents and the amount of water added on conversion rates were studied. A maximum conversion yield of 80% in n-hexano at 48 h was obtained under the followi (mais) ng conditions: 3 g L-1 of Lipozyme TL IM, 30 ºC, 180 rpm of agitation, isoamyl alcohol to butyric acid molar ratio of 1:1 and acid substrate concentration of 0.06 M.

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6

Organo-gel: um novo sistema para a imobilização de lipases e sua aplicação em síntese orgânica/ Organogels: a new system for lipases immobilization and its application in organic synthesis

Jesus, Paulo Cesar de; João, Jair Juarez; Silva, Pedro Luiz Ferreira da; Burlin, Giovani; Nascimento, Maria da Graça
1997-12-01

Resumo em inglês Lipases have been immobilized in microemulsion-based organogels (MBG's) and successfully utilized for the enantioselective esterification, diesterification and transesterification reactions, in organic solvents at 25ºC. This methodology is described as a new alternative for the use of enzymes in organic solvents. High enzymic stability has been observed. We have also used this methodology for the successful resolution of chiral secondary alcohols. This is a convenient way of using this catalyst in organic solvents which employs small amounts of the enzyme (250mg/mL).

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7

Imobilização de lipases em filme de caseinato de sódio/glicerol: aplicação na síntese de ésteres/ Lipase immobilization in sodium caseinate/glycerol film: application in ester synthesis

Sebrão, Damianni; Silva, Vanessa Dutra; Nascimento, Maria da Graça; Moreira, Marcelo Alves
2007-10-01

Resumo em inglês Lipases from different sources were immobilized in sodium caseinate/glycerol film and used in the esterification reactions of aliphatic acids with alcohols in the presence of organic solvents. Lipases from Pseudomonas sp and Rhizopus oryzae were selected and the influence of several parameters was analyzed, including: lipase loading, organic solvent polarity, reaction temperature, chain length of alcohol and acid and enzyme/support reuse. For comparison, free enzymes were used under similar experimental conditions.

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8

Imobilização de enzimas em suportes cromatográficos: uma ferramenta na busca por substâncias bioativas/ Immobilization of the enzymes on chromatographic supports: a tool to research of inhibitor compounds

Cardoso, Carmen Lúcia; Moraes, Marcela C. de; Cass, Quezia B.
2009-01-01

Resumo em inglês The development and characterization of bioreactors or IMER (immobilized enzyme reactors) as research tools are important in the scope of medicinal chemistry and constitute an alternative for the rational development of drugs. This approach does not require highly purified enzymes or a great amount of protein, but increase the enzymatic stability against heat, organic solvents and pH, without too much loss of catalyst activity. Immobilized enzyme reactors (IMER) can be us (mais) ed for the accomplishment of high efficiency screening on-line and, thus inhibitors can be quickly identified. Here, we emphasize the development of IMER by use of different methods of immobilization and chromatographic supports. Their applications, in different areas of research, are also fully discussed.

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9

Imobilização de enzimas a partir de "kit" comercial: determinação de parâmetros metabólicos em sangue animal empregando multicomutação em fluxo/ Enzyme immobilization using a commercial kit: determination of metabolic parameters in animal blood employing a multicommutation flow system

Pires, Cherrine Kelce; Reis, Boaventura Freire dos
2005-06-01

Resumo em inglês Automatic flow procedures based on the multicommutation concept, dedicated to the determination of 3-hydroxybutyrate, glucose and cholesterol are proposed. The enzymes were immobilized on glass beads and packed into mini-columns that were coupled to a flow system. Sampling throughputs of 55, 40 and 40 determinations per hour, linear response from 10 to 150, 50 to 600, 25 to 125 mg L-1, detection limits of 1.5, 14 and 4 mg L-1 and relative standard deviations of 1, 2 and 2% for 3-hydroxybutyrate, glucose and cholesterol, respectively, were achieved.

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10

Biossensores baseados no processo de inibição enzimática/ Biosensors based on the enzymatic inhibition process

Marques, Paulo Roberto Brasil de Oliveira; Yamanaka, Hideko
2008-01-01

Resumo em inglês Fast, selective, reproducible and reliable detections have been carried out by using enzymatic biosensors in several areas. The enzymatic biosensors based on the inhibition represent an important role in analytical chemistry. Enzymes like cholinesterases, peroxidases, tyrosinases, etc. have been immobilized on electrochemical and optical transducers and the enzymatic activity decreasing in the presence of the inhibitor is related with its concentrations. This article pres (mais) ents a review on the enzymes used on the construction of these sensors, emphasizing the respective applications.

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11

Biodiesel: visão crítica do status atual e perspectivas na academia e na indústria/ Biodiesel: a critical overview on the current status and perspectives at the academy and industry

Dabdoub, Miguel J.; Bronzel, João L.; Rampin, Márcia A.
2009-01-01

Resumo em inglês This article presents a bibliographic review of research carried out on different alternative processes for biodiesel production. The supercritical and subcritical (non catalytic) reaction conditions, the use of solid basic, solid acid and other heterogeneous catalysts, including the use of immobilized enzymes and whole-cell catalysts are also critically compared with the traditional homogeneous alkaline or acid catalysts that are common on industrial applications. Advant (mais) ages and limitations of all these processes for the transference from the laboratory to the industry are discussed. A correlation of the chemical composition with the quality parameters of the produced biodiesel is done with aim to stablish adequate procedures for the right selection of the raw-material. Castor bean oil is used as an example of inappropriate oil in order to produce a B100 that fulfill all the international physico-chemical quality standards. In this article are presented research results to adequate the values of viscosity, density and iodine number of the castor and soybean biodiesel to the international standard limits by means blending these both biodiesels at the right ratio.

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12

Bioacetilação de álcoois catalisada por Saccharum officinarum/ Bioacetylation of alcohols catalysed by Saccharum officinarum

Assunção, João Carlos C.; Lemos, Telma Leda G.; Monte, Francisco José Q.
2009-01-01

Resumo em inglês Lipase-catalysed esterifications of alcohols using immobilized enzyme system from sugar cane (Saccharum officinarum) as biocatalyst afforded the corresponding esters in considerable yields (68-93%). Under optimized conditions, the material was utilized for reactions of acetylation with several advantage. It also investigated the possibility of reuse of immobilized enzymes of S. officinarum as biocatalyst under optimal reaction conditions.

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13

Aplicações sintéticas de lipases imobilizadas em polímeros/ Synthetic applications of immobilized lipases in polymers

Dalla-Vecchia, Roberto; Nascimento, Maria da Graça; Soldi, Valdir
2004-08-01

Resumo em inglês The application of biocatalysis is a promising field related to new technologies for organic synthesis. The development of immobilization techniques is very important due to the multiple or repetitive use of a single batch of enzymes and the ability to stop the reaction rapidly, at any stage, by removing the enzymes. In most cases, after immobilization, enzymes and microorganisms maintain or even increase their activity and stability. This work presents an overview of the (mais) common methods for lipase immobilization in polymers and applications of these systems to obtain compounds of synthetic interest.

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14

Alternativa potencial para aproveitamento do glicerol gerado na produção de biodiesel: síntese enzimática de monolaurina por esterificação/ Potential alternative for using the glycerol generated in the biodiesel production: enzymatic synthesis of monolaurin by esterification

Freitas, Larissa; Santos, Julio C.; Barcza, Marcos V.; Castro, Heizir F. de
2009-01-01

Resumo em inglês Esterification reactions of glycerol with lauric acid in solvent free system were carried out using lipases from several sources. All lipases were immobilized on polysiloxane-polyvinyl alcohol particles by covalent binding with high activity recovered. Among the tested enzymes, the Candida antarctica lipase allowed to attain the highest molar conversion (76%), giving similar proportions of monolaurin, dilaurin and low amount of trilaurin. To further improve the process, t (mais) he Response Surface Methodology (RSM) was used and optima temperature and molar ratio glycerol to lauric acid were found to be 45 ºC and 5:1, respectively. Under these conditions, 31.35% of monolaurin concentrations were attained and this result was in close agreement with the statistical model prediction.

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