Assessment of encapsulation of digestive enzymes recovered from South Atlantic fish wastes for potential biotechnological applications

Fish viscera represent an abundant and cost-effective source of digestive enzymes, particularly proteinases, which can be readily extracted and employed as bioactive components in various industrial processes to obtain value-added products. However, proteinases are sensitive to environmental factors. A successful method for maintaining their enzymatic activity is encapsulation. The aim of this study was to evaluate the encapsulation efficiency of alkaline and acid proteinases derived from wastes of the commercial fish species Merluccius hubbsi and Percophis brasiliensis from the Southwest Atlantic Ocean, and to determine the stability of their enzymatic activity under different storage conditions (room temperature and 4ºC). In addition, the effectiveness of the encapsulated proteinases using an in vitro digestion simulation assay was assessed. The results indicated that P. brasiliensis proteinases immobilized in fresh microcapsules and stored at 4°C remained stable for 60 days. Alkaline proteinases stored in freeze-dried microcapsules from both species, and fresh microcapsules from P. brasiliensis, retained their activity at both storage temperatures for 60 days. Aspartic proteinases from both species, encapsulated in freeze-dried capsules and stored at 4°C, maintained catalytic activity. In vitro enzymatic hydrolysis assays confirmed that casein is hydrolyzed after 60 min by both the encapsulated and free enzymes. In turn, the amount of free amino acids released from casein leveled off after 180 min of in vitro assay. These results evidenced that encapsulation using a combination of alginate and chitosan is a promising tool for different biotechnological applications of these fish enzymes such as elaboration of commercial detergent additives and aquafeeds.