beta-galactosidase from Aspergillus oryzae was immobilized in fibers composed of alginate and gelatin hardened with glutaraldehyde. Immobilization resulted in 56% relative activity retained for 35 days without decrease. The optimum conditions were not affected by immobilization, and the optimum pH and temperature for free and immobilized enzyme were 4.5 and 50 degreesC, respectively. Immobilized beta-galactosidase was more stable at high pH and temperatures. The kinetic parameters for soluble and immobilized beta-galactosidase were also determined. The newly developed immobilization method is simple, yet effective and can be used for the immobilization of other enzymes. (C) 2002 Elsevier Science Ltd. All rights reserved.