Concentração e purificação de Beta-amilase de extrato de soja por adsorção em gel de afinidade quitosana-fenilboronato

AUTOR(ES)
DATA DE PUBLICAÇÃO

1999

RESUMO

B-amylase (E.C 3.2.1.2) is an enzyme that hydrolyses non-reduced ends of starch and maltooligossacarides producing units of maltose. The main industrial application of this enzyme is the production of high maltose syrup. The traditional sources of B-amylase are plants and microorganism. Since its main use is found in food processing, the production cost of the enzyme must be low. Therefore, the downstream processing for this case has an important role in process economics. The objetive of this work was the synthesis of a pseudo-affinity adsorbent to recovery and purify B-amylase from soybean extract. The used pseudo-affinity ligand was phenylboronate and the performance of agarose and crosslinked chitosan as matrix were compared in this work. Glutaraldehyde crosslinked matrixes were obtained by aIkaline coagulation of chitosan solution followed by treatment with glutaraldehyde. This treatment had two goals: to crosslink the chitosan gel and to provide aldehyde groups for ligand coupling at pH 8. The matrix was characterized for its ligand density, particle size distribution, pore size distribution, thermostability, morphology and specific surface area. The achieved density of the ligand in the support produced in this work (PBC) was compared to the ligand density of PBA-30 a commercial support (up to 100 mmoles.mL-1). Pore size distribution analysis indicated that matrix had macroporous that can be controlled by the alkaline coagulation conditions. Studies of f3-amylase recovery and purification from soybean extracts with chitosan-phenylboronate matrix were carried out by adsorption isotherm, breakthrough curves, and chromatographic profile determinations. Adsorption isotherms and breakthrough curves indicated that the produced matrix had similar capacities compared to PBA 30. Assays in a chromatographic column lead to 45% activity recovery and 4-fold purification factor. The binding of f3-amylase and impurities onto PBC was much stronger than onto PBA 30: elution from PBC required solutions with 5-fold higher NaCI concentration, what suggests that electrostatic interactions is the main mechanism for binding. The similar chemical and physical characteristics and chromatographic behavior of PBC 100 compared to PBA 30 indicated the potencial of the PBC matrix as an adsorbent for large-scale application

ASSUNTO(S)

compostos organoboro adsorção aldeidos quitosana

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