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| Yan,Xu; Souza,Maria Aparecida; Pontes,Marcela Z. R.; Vitolo,Michele; Pessoa Júnior,Adalberto. |
| From analytical to commercial scale, aqueous two-phase systems have their application in the purification, characterization and study of biomaterials. In order to improve the selectivity of the systems, the biospecific affinity ligands were introduced. In the affinity partitioning aqueous two-phase system, have many enzymes been purified. This review discusses the partitioning of some enzymes in the affinity aqueous two-phase systems in regard to the different ligands, including reactive dyes, metal ions and other ligands. Some integration of aqueous two-phase system with other techniques for more effective purification of enzymes are also presented. |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Affinity partitioning; Aqueous two-phase systems; Reactive dyes; Ligands; Enzymes. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132003000400030 |
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| Erzinger,Gilmar Sidnei; Silveira,Mauricio Moura da; Costa,José Paulo Castilho Lopes da; Vitolo,Michele; Jonas,Rainer. |
| Previously grown cells of the ethanologenic bacterium Zymomonas mobilis produce sorbitol and gluconic acid, in reactions catalysed by the periplasmic enzymes glucose-fructose oxidoreductase (GFOR) and glucono-delta-lactonase (GL). The GFOR/GL system activity, in cells to be used in this bioconversion, depends on growth conditions. In batch runs, with initial glucose concentrations (S0) from 42 to 230 g/L, the highest specific and total GFOR/GL activities were obtained with S0 = 153 g/L (12.6 U/g cells and 62 U/L). Higher S0 led to decreasing activities in fresh cells. With S0 = 209 g/L, the final specific activity was only 7.0 U/g. After disruption of cells, however, an activity over 15 U/g was revealed. Since growth inhibition with S0 over 153 g/L was... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Zymomonas mobilis; Glucose-fructose oxidoreductase; Glucose. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822003000400008 |
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| Silva,Daniel Pereira da; Pontes,Marcela Zanella Ribeiro; Souza,Maria Aparecida de; Vitolo,Michele; Silva,João Batista de Almeida e; Pessoa-Junior,Adalberto. |
| Glucose-6-phosphate dehydrogenase (G6PDH) and hexokinase (HK) are important enzymes used in biochemical and medical studies and in several analytical methods. Aqueous two-phase system (ATPS) formed by a polymer solution and an electrolyte solution provides a method for the separation and purification of enzymes with several advantages, including biocompatibility and easy scale up of the process. In this work, the effects of different pH values on the storage stability and partitioning behavior (K, partition coefficient) of the enzymes G6PDH and HK from baker's yeast extract were investigated in ATPS. The results, obtained from the 17.5% PEG 400 : 15.0% phosphate system, showed that when the pH was increased from 5.0 to 8.8, the K HK increased 26-fold and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Aqueous two-phase systems; Partition coefficient; Protein purification; Hexokinase; Glucose 6-phosphate dehydrogenase. |
| Ano: 2002 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822002000300002 |
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| Ribeiro,Marcela Zanella; Silva,Daniel Pereira; Vitolo,Michele; Roberto,Inês Conceição; Pessoa-Jr,Adalberto. |
| Glucose-6-phosphate dehydrogenase (G6PDH) is an important enzyme used in biochemical and medical studies and in several analytical methods that have industrial and commercial application. This work evaluated the extraction of G6PDH in aqueous two-phase system (ATPS) of poly(ethyleneglycol) (PEG)/phosphate buffer, using as enzyme source a medium prepared through commercial baker's yeast disruption. Firstly, the effects of PEG molar mass on the enzyme partition and of homogenization and rest on the system equilibrium were investigated. Afterwards, several ATPS were prepared using statistical analysis (2² factorial design). The results, including kinetic and thermodynamic parameters for the G6PDH activity, showed partial purification of this enzyme in ATPS... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Aqueous two-phase systems; Glucose-6-phosphate dehydrogenase; Liquid-liquid extraction; Saccharomyces cerevisiae. |
| Ano: 2007 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822007000100016 |
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| Tomotani,Ester Junko; Vitolo,Michele. |
| Invertase, whether adsorbed on styrene-divinylbenzene copolymers or otherwise, was used for continuous sucrose hydrolysis using a cell-type membrane reactor (CTMR), coupled with an ultra (UF-100kDa), or a microfiltration (MF- pore diameter of 5 µm) membrane. In all tests, the pH (5.5), temperature (30 ºC), reaction volume (10 mL) and agitation (100 rpm) were set constant; whereas, variable parameters were: feeding rate (0.4, 0.8 and 1.6 h-1), inlet sucrose concentration (2.5, 6.5, 50 and 100 mM) and enzyme/resin ratio (1.64 mg or 3.28 mg of protein per 25, 50 or 100 mg of resin). The best result (yield of 100%, steady-state duration over 20h and specific reaction rate over 243 x 10-3 mmol/h.mE) was obtained when insoluble invertase (1.64 mg protein/100 mg... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Sucrose; Invert sugar; Membrane reactor. |
| Ano: 2010 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1984-82502010000300022 |
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| Silva,Aline Ramos da; Tomotani,Ester Junko; Vitolo,Michele. |
| Conversion of sucrose into fructose and gluconic acid using invertase, glucose oxidase and catalase was studied by discontinuous (sequential or simultaneous addition of the enzymes) and continuous (simultaneous addition of the enzymes in a 100 kDa-ultrafiltration membrane reactor) processes. The following parameters were varied: concentration of enzymes, initial concentration of substrates (sucrose and glucose), pH, temperature and feeding rate (for continuous process). The highest yield of conversion (100%) was attained through the discontinuous (batch) process carried out at pH 4.5 and 37 ºC by the sequential addition of invertase (14.3 U), glucose oxidase (10,000 U) and catalase (59,000 U). |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Sucrose/conversion; Fructose; Gluconic acid; Invertase; Glucose oxidase; Catalase. |
| Ano: 2011 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1984-82502011000200022 |
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