RESUMO
The interaction of tannase (TAH) with chitosan, polyethyleneimine and Eudragit(®)E100 was studied. It was found that TAH selectively binds to these polycations (PC), probably due to the acid nature of the target protein. TAH could interact with these PC depending on the medium conditions. The effect of the interaction on the secondary and tertiary structure of TAH was assayed through circular dichroism and fluorescence spectroscopy. TAH was recovered from Aspergillus niger culture broth by means of precipitation and adsorption using chitosan.
Assuntos
Acrilatos/química , Aspergillus niger/enzimologia , Hidrolases de Éster Carboxílico/química , Quitosana/química , Polietilenoimina/química , Polímeros/química , Acrilatos/metabolismo , Hidrolases de Éster Carboxílico/metabolismo , Cátions/química , Cátions/metabolismo , Quitosana/metabolismo , Dicroísmo Circular , Polietilenoimina/metabolismo , Polímeros/metabolismo , Cloreto de Sódio/química , Espectrometria de FluorescênciaRESUMO
Interactions between catalase and the cationic polyelectrolytes: chitosan and Eudragit E100 have been investigated owing to their scientific and technological importance. These interactions have been characterized by turbidimetry, circular dichroism and fluorescence spectroscopy. It was found that the catalase conformation does not change significantly during the chain entanglements between the protein and the polyelectrolytes. The effects of pH, ionic strength and anions which modify the water structure were evaluated on the polymer-protein complex formation. A net coulombic interaction force between them was found since the insoluble complex formation decreased after the NaCl addition. Both polymers were found to precipitate around 80% of the protein in solution. No modification of the tertiary and secondary protein structure or the enzymatic activity was observed when the precipitate was dissolved by changing the pH of the medium. Chitosan and Eudragit E100 proved to be a useful framework to isolate catalase or proteins with a slightly acid isoelectrical pH by means of precipitation.
Assuntos
Acrilatos/química , Catalase/química , Quitosana/química , Poliaminas/química , Polímeros/química , Acrilatos/metabolismo , Animais , Catalase/isolamento & purificação , Catalase/metabolismo , Bovinos , Precipitação Química , Quitosana/metabolismo , Dicroísmo Circular , Estabilidade Enzimática , Humanos , Concentração de Íons de Hidrogênio , Nefelometria e Turbidimetria , Poliaminas/metabolismo , Polieletrólitos , Polímeros/metabolismo , Ligação Proteica , Solubilidade , Espectrometria de Fluorescência , Temperatura , TitulometriaRESUMO
In biotechnological processes, a great number of factors can influence the income productivity and conversion. Normally, it is not evident which of these factors are the most important and how they interact. In this work, multivariate analysis techniques are used as experimental design coupled to a detailed deterministic model to identify the parameters with the most significant impact on the model to represent well the acrylic acid production process. It is proposed as an alternative process, having sugarcane as feedstock, to the petrochemical-based ones that have significant environmental impacts for their production. To increase the competitiveness of renewable acrylic-acid-based process, it is necessary to find out working conditions near the optimal region, which is not an easy task, as the process is multivariable and non-linear. The mapping of the dynamics of the developed process is made using techniques of factorial design together with the methodology of Plackett-Burman. It is shown that it is possible to increase the process performance by choosing optimized conditions for the reactor operation.
Assuntos
Acrilatos/metabolismo , Algoritmos , Glucose/metabolismo , Modelos Biológicos , Ácido Pirúvico/metabolismo , Saccharomyces cerevisiae/metabolismo , Saccharum/microbiologia , Simulação por Computador , CinéticaRESUMO
With the synthesis of chemical products through biotechnological processes, it is possible to discover and to explore innumerable routes that can be used to obtain products of high added value. Each route may have particular advantages in obtaining a desired product, compared with others, especially in terms of yield, productivity, easiness to separate the product, economy, and environmental impact. The purpose of this work is the development of a deterministic model for the biochemical synthesis of acrylic acid in order to explore an alternative process. The model is built-up with the tubular reactor equations together with the kinetic representation based on the structured model. The proposed process makes possible to obtain acrylic acid continuously from the sugar cane fermentation.
Assuntos
Acrilatos/metabolismo , Reatores Biológicos/microbiologia , Técnicas de Cultura de Células/métodos , Modelos Biológicos , Saccharomyces cerevisiae/metabolismo , Simulação por Computador , FermentaçãoRESUMO
From the stem bark of Bowdichia virgilioides, lupeol, lupeol acetate, sitosterol, stigmasterol and methyl-3-[2-(1-hydroxymethylvinyl)-2,3-dihydrobenzo[b]furan-5-yl]-(E)-2-propenoate have been isolated. The latter is a new compound and it has been named as bowdenol. Their structures were elucidated with the aid of spectroscopic techniques, mostly 1 and 2D NMR. The biogenetic pathway for bowdenol has been suggested.
Assuntos
Benzofuranos/isolamento & purificação , Fabaceae/química , Plantas Medicinais/química , Acrilatos/química , Acrilatos/metabolismo , Benzofuranos/química , Brasil , Catálise , Cromatografia em Camada Fina , Ácidos Cumáricos/química , Ácidos Cumáricos/metabolismo , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Casca de Planta/química , Caules de Planta/química , Ácido Chiquímico/química , Ácido Chiquímico/metabolismo , Espectrofotometria Infravermelho , Espectrofotometria Ultravioleta , Fosfatos Açúcares/química , Fosfatos Açúcares/metabolismo , Tirosina/química , Tirosina/metabolismoRESUMO
The aim of this study is to evaluate the thrombogenic behaviour of the low density polyethylene and poly(vinyl chloride) modified by radiation-grafting technique. After copolymerization with acrylic acid by gamma-rays from a 60Co source, BSA was immobilized onto functionalized graft copolymers. The biological interaction between these materials and blood was studies by in vitro methods. The BSA immobilization effectively suppressed the adhesion and activation of platelets when it contacted whole blood.