Tannase produced by Paecilomyces variotii was encapsulated in sodium alginate beads and used for the effective hydrolysis of tannic acid; the efficiency of hydrolysis was comparable to that of the free enzyme. The alginate beads retained 100%% of their efficiency in the first three rounds of successive use and 60%% in rounds 4 and 5. The response surface methodology showed that the best conditions to hydrolysis of tannic acid by immobilized tannase were: sodium alginate 5.2%%, CaCl(2) 0.55 M and 9 h to curing time. The optimized process resulted in 2.4 times more hydrolysed tannic acid than that obtained before optimization. The optimum pH for the actions of both the encapsulated and the free enzymes was 5.5. The optimum temperature of the reaction was determined to be 40 degrees A degrees C for the free enzyme and 60 degrees A degrees C for the immobilized form. The immobilization process improved the stability at low pH.