41 research outputs found

    Optimal Conditions for Continuous Immobilization of Pseudozyma hubeiensis (Strain HB85A) Lipase by Adsorption in a Packed-Bed Reactor by Response Surface Methodology

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    This study aimed to develop an optimal continuous process for lipase immobilization in a bed reactor in order to investigate the possibility of large-scale production. An extracellular lipase of Pseudozyma hubeiensis (strain HB85A) was immobilized by adsorption onto a polystyrene-divinylbenzene support. Furthermore, response surface methodology (RSM) was employed to optimize enzyme immobilization and evaluate the optimum temperature and pH for free and immobilized enzyme. The optimal immobilization conditions observed were 150 min incubation time, pH 4.76, and an enzyme/support ratio of 1282 U/g support. Optimal activity temperature for free and immobilized enzyme was found to be 68°C and 52°C, respectively. Optimal activity pH for free and immobilized lipase was pH 4.6 and 6.0, respectively. Lipase immobilization resulted in improved enzyme stability in the presence of nonionic detergents, at high temperatures, at acidic and neutral pH, and at high concentrations of organic solvents such as 2-propanol, methanol, and acetone

    Immobilization of Peroxidase onto Magnetite Modified Polyaniline

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    The present study describes the immobilization of horseradish peroxidase (HRP) on magnetite-modified polyaniline (PANImG) activated with glutaraldehyde. After the optimization of the methodology, the immobilization of HRP on PANImG produced the same yield (25%) obtained for PANIG with an efficiency of 100% (active protein). The optimum pH for immobilization was displaced by the effect of the partition of protons produced in the microenvironment by the magnetite. The tests of repeated use have shown that PANImG-HRP can be used for 13 cycles with maintenance of 50% of the initial activity

    Antioxidant and anitoperoxidative effect of polypeptides from common beans (Phaseolus vulgaris, cv BRS Pontal) / Efeito antioxidante e anitoperoxidativo dos polipéptidos do feijão comum (Phaseolus vulgaris, cv BRS Pontal)

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    Common beans have high content of protein and can be used as source for obtaining bioactive peptides which are compounds that exhibit an effect on body functions or conditions and may influence human health. This study was undertaken to examine the antioxidant and antiperoxidative potential of naturally-occurring peptides from easy-to-cook (ETC) and hard-to-cook (HTC) beans (Phaseolus vulgaris, cv BRS Pontal). The extracted proteins were partially purified using ultrafiltration membranes. Thereafter, the antioxidant activity of the produced fractions was analyzed by DPPH and FRAP methods. The lipid peroxidation was measured by thiobarbituric acid reactive substances (TBARS) analysis. Results evidenced that the antioxidant potential was highly improved after ultrafiltration, especially for those fractions containing molecules with low molecular weight. Peptide fractions (F3-10kDa) from ETC beans exhibited a better ability to inhibit the reactive oxygen species formation when compared to the synthetic antioxidant BHT, which corroborates their antioxidant role and protection against lipid peroxidation. Regarding the peptide fractions from HTC beans, the samples had similar lipid peroxidation to BHT in the tested concentration range (200 to 600?g). The HTC phenomenon did not seem to affect definitively the bioactivity of the bioactive peptides, suggesting that it is possible to use these components as an alternative for the use of the grains affected by the hardening process

    Educomunicação e suas áreas de intervenção: Novos paradigmas para o diálogo intercultural

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    oai:omp.abpeducom.org.br:publicationFormat/1O material aqui divulgado representa, em essência, a contribuição do VII Encontro Brasileiro de Educomunicação ao V Global MIL Week, da UNESCO, ocorrido na ECA/USP, entre 3 e 5 de novembro de 2016. Estamos diante de um conjunto de 104 papers executivos, com uma média de entre 7 e 10 páginas, cada um. Com este rico e abundante material, chegamos ao sétimo e-book publicado pela ABPEducom, em seus seis primeiros anos de existência. A especificidade desta obra é a de trazer as “Áreas de Intervenção” do campo da Educomunicação, colocando-as a serviço de uma meta essencial ao agir educomunicativo: o diálogo intercultural, trabalhado na linha do tema geral do evento internacional: Media and Information Literacy: New Paradigms for Intercultural Dialogue

    Immobilized Horseradish Peroxidase on Discs of Polyvinyl Alcohol-Glutaraldehyde Coated with Polyaniline

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    Discs of network polyvinyl alcohol-glutaraldehyde (PVAG) were synthesized and coated with polyaniline (PANI) using glutaraldehyde as a chemical arm (PVAG-PANIG-HRP disc). The best conditions for the immobilization were established as about 1.0 mg mL−1 of protein, for 60 min and pH 5.5. The soluble enzyme lost all of its activity after incubation at 70°C for 15 min, whereas the PVAG-PANIG-HRP disc retained about half of the initial activity for pyrogallol. The same PVAG-PANIG-HRP disc was used consecutively three times without any activity lossbut presented 25% of the initial activity after the 7th use. PVAG-PANIG-HRP disc retained approximately 80% and 60% of its initial activity after 60 and 80 days of storage, respectively. Resorcinol, m-cresol, catechol, pyrogallol, α-naphthol, βnaphthol, and 4, 4′-diaminodiphenyl benzidine were efficiently oxidized by the PVAG-PANIG-HRP disc (from about 70% to 90%), and it was less efficient towards aniline, phenol, and 2-nitrosonaphthol
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