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Covalent immobilization of corn cellulose derivative of beta galactosidase from aspergillus fonsecaeus comparison with beta galactosidase from aspergillus oryzae

Gonzalez, R.; Monsan, P.; Ros, O.; Escale, F.

Interferon y Biotecnologia 5(3): 237-244

1988


Accession: 007166337

.beta.-galactosidase from Aspergillus fonsecaeus with a specific activity between 19-24 U/mg, at concentrations 1.6-3.3 g/l and pH 8.6 was covalently immobilized with high yield (667 U/g) on corn cellulose derivatives (CCD). The highest percentage of immobilized enzyme and the highest values of enzymatic activity per gram of support, were obtained with CCD particles of 0.8 mm. We determined some kinetic characteristics of immobilized .beta.-galactosidasae from A. fonsecaeus and A. oryzae in an anti-diffusional reactor using ONPG and lactose as substrates. The immobilized enzyme form A. fonsecaeus showed lower apparent Km values than that from S. oryzae, in contrast to what occurs when they are both in the free form. Continuous hydrolysis of lactose solution in reactors containing columns packed with CCD-.beta.-galactosidase from both sources yielded similar results, which are comparable to those reported for other systems. The immobilized enzyme from A. fonsecaeus was considerably stable, presenting half lives of 240 and 80 days at 35.degree. C and 50.degree. C, respectively. It may be employed for the continuous hydrolysis of whey at 50.degree. C and pH 4, with a productivity of 0.9 galactose/g, CCD-enzyme/hour.

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