The protease from Bacillus licheniformis, commercially known as Alcalase (R), was insolubilized and stabilized by immobilization onto activated chitosan. Activation with different agents, such as glutaraldehyde (GLU-Chi), glyoxyl (GLY-Chi) and divinyl sulfone (DVS-Chi) was investigated. The effect of the immobilization protocol, for instance different pH and times, were also evaluated. GLU-Chi showed the highest activity (35.6UNPA/g) with the smallest substrate (N-Boc-L-alanine p-nitrophenyl-ester, NPA), while GLY-Chi showed the highest activity (1.5 UAzocasein/g) using the greatest substrate (azocasein). A 24-h immobilization period was enough to stabilize the enzyme using the three supports under almost all conditions. Operational stability in azocasein hydrolysis was assayed and GLU-Chi showed no activity loss during 5 cycles. DVS-Chi retained around 70 % of its initial activity after the fifth cycle, whereas GLY-Chi activity retained only 10 %. Finally, the biocatalysts were used in the hydrolysis of tilapia skin gelatin aiming the production of peptides with antioxidant activity. The protein hy-drolysates obtained using GLU-Chi presented the highest antioxidant activity (36.7 mu M Trolox Eq). However, the best results of operational stability were obtained using DVS-Chi, which did not lose its initial activity after 3 consecutive cycles of gelatin hydrolysis.