For assessment of materials susceptibility to enzymatic degradation, a microbial lipase from Candida antarctica was used (Sigma Aldrich, Germany). Samples were cut into 1 cm 2 square shapes and placed into a 5 mL Falcon tube. Next, 3.0 mL of lipase solution was added to the samples at a concentration of 25.0 U/ml. Sodium azide (POCh, Gliwice, Poland) was added to prevent the growth of bacteria. To maintain stable level of enzyme activity the solution was changed every 7 days up to 28 days.