The glucoamylase from Aspergillus niger was immobilized into a poly(vinylalcohol) hydrogel lens-shaped capsules LentiKats (R). Immobilization broadened the pH optimum of the enzyme. The K-M of glucoamylase increased after immobilization (approximately 1.5 times on maltose), which reflected the decrease in affinity of enzyme for its substrate. Immobilized enzyme retained excellent long-term operational stability for both, batch and continuous mode of hydrolysis. Specific enzymatic activity of the immobilized enzyme (0.67 g g(-1) h(-1)) was constant for 63 days of continuous operation at 45 degrees C. (c) 2006 Elsevier Inc. All rights reserved.