Synthesis of Polymeric Matrices for Adsorption and Purification of Endoglucanase

摘要

Chitosan (CHS), chitosan-Eudragit (R) EPO (CHS-EPO) and chitosan beads partially cross-linked with glutaraldehyde (CHS-GLUT) were obtained in order to improve the adsorption selectivity of endoglucanase from a fungal culture obtained under SSF by Aspergillus niger using soybean harvest residues as support. The matrices synthetized were characterized in terms of physical and chemical changes. Fourier-transformed infrared spectroscopy with attenuated total reflectance device (FTIR-ATR) was employed to verify the chemical changes on the CHS matrix after the synthesis of CHS-GLUT and CHS-EPO. Scanning electron microscopy (SEM) was performed to compare the surface morphology of the polymeric beads. Two variables, purification factor and yield percentage of the adsorption process, were analyzed using a bifactorial ANOVA considering the matrix-time first order interaction. SEM results exhibited greater surface roughness in the CHS-GLUT and CHS-EPO matrices which may enhance endoglucanase adsorption. FTIR-ATR results confirmed an effective chemical modification of the CHS matrix after crosslinking with GLUT and corroborated the efficiency of the synthesis of the CHS-EPO matrix by the presence of chemical groups of the EPO polymer. An endoglucanase purification factor close to 9 was achieved with the CHS-GLUT matrix and a yield percentage of 60% was obtained with the CHS-EPO matrix. Bifactorial ANOVA results showed the matrix-time interaction to be significant for both variables. The CHS-GLUT matrix with low crosslinking times and the novel CHS-EPO matrix could be included in the bioseparation stage of endoglucanase using a simple and a low-cost method such as batch adsorption.