beta-D-Glucosidase was immobilised by entrapment in two different matrices (calcium alginate and polyacrylamide gels), in order to compare how the immobilisation could stabilise the enzyme towards thermal and proteolytic deactivation. While the enzyme trapped in polyacrylamide gel showed an optimum temperature for activity at 10 degrees C lower than that of the free enzyme, the optimal temperature after immobilisation in alginate beads was not altered (60 degrees C). The immobilisation of enzyme in alginate beads caused a larger increase in the thermal stability than the entrapment in polyacrylamide gels. The stabilisation factors obtained as 55, 60 and 65 degrees C for beta-glucosidase immobilised in alginate and polyacrylamide gels were 2.03, 3.06, 2.19 and 2.04. 0.35, 1.01, respectively. In contrast, the beta-glucosidase immobilised in polyacrylamide gels was more resistant in proteolysis than that trapped in alginate beads.