Extração da ascorbato oxidase de Cucurbita maxima por processo descontínuo e contínuo em coluna de discos rotativos perfurados utilizando sistemas de duas fases aquosas / Extraction of ascorbate oxidase from Cucurbita maxima by discontinuous and continuous process in perforated rotating disc contactor using aqueous two-phase systems.

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

The partition and purification of ascorbate oxidase from pumpkin (Cucurbita maxima) by liquid-liquid extraction in aqueous two-phase system (ATPS) by discontinuous and continuous process, using perforated rotating disc contactor (PRDC) was studied. Experimental designs were used to choose the significant variables for discontinuous process, and polyethylene glycol (PEG) molar mass and concentration, citrate concentration, pH, NaCl concentration, dilution factor and total mass of the system, were the variables studied. The better results (partition coefficient 1.72, recovery 90.8% and purification factor 3.12) were obtained with following conditions: PEG molar mass of 20000 g/mol, pH 6.0, PEG concentration of 25% (w/w) and citrate concentration of 10% (w/w). In the pH 6.0 and temperature of 35?C the ascorbate oxidase showed their high activity values and the enzyme was stable in the pH range of 5.0 to 9.0 during 36 hours and temperatures up to 40?C for 1 hour. Experiments were also conducted to estimate the main kinetic and thermodynamic properties of ascorbate oxidase activity and stability, and this study revealed the interesting stability of this enzyme. The PRDC showed a good performance for extracting in continuous mode using aqueous two-phase systems. The best operating condition was selected in this study for the extraction of ascorbate oxidase in the PRDC, and it was obtained with PEG molar mass of 20000 g/mol, PEG concentration of 20% (w/w) and citrate concentration of 10% (w/w), the disc rotational speed of 80 rpm and dispersed phase flowrate of 2 mL/min. The results in mean values were: partition coefficient 3.36, recovery 152%, purification factor 2.31, mass transfer coefficient 0.045, separation efficiency 43.7% and Hold up 0.33. The experimental data showed the potential application of aqueous two-phase systems PEG/citrate to purification ascorbate oxidase using perforated rotating disc contactor.

ASSUNTO(S)

alimentos peg/citrate sistemas de duas fases aquosas aqueous two-phase systems Ácidos ascórbicos biotecnolgy proteinas enzimas peg/citrato enzymes soluções aquosas biotecnologia perforated rotating disc contactor ascorbato oxidase fármacos coluna de discos perfurados rotativos ascorbate oxidase

ACESSO AO ARTIGO

Documentos Relacionados