Selection of the Optimal Medium for Adsorption of Plant Protease

: Immobilized enzymes are the most sought-after preparations in the global market. They are used in medicine, veterinary medicine, the food industry, winemaking and brewing. The simplest method for immobilizing biocatalysts on insoluble carriers is the simple adsorption method. Its advantage is that it preserves the natural conformation of the enzyme, which slightly reduces its catalytic ability compared to the native form. In our study, we carried out the selection of optimal conditions for adsorption immobilization of acid-soluble chitosan (Mr = 350 kDa) enzymes of plant origin (ficin, papain and bromelain) on a matrix. Ficin (EC 3.4.22.3), papain (EC 3.4.22.2) and bromelain (EC 3.4.22.4) (Sigma) were chosen as the objects of study, azocasein (Sigma) was used as a substrate for hydrolysis and an acid-soluble high-molecular-weight chitosan (350 kDa) was used as an immobilization matrix, synthesized by Bioprogress CJSC. Suitable buffer systems for immobilization were identified by the optimal ratio of protein content and total and specific activity. Ficin is immobilized on a chitosan matrix using glycine buffer with a pH of 8.6. Glycine buffer with a pH of 8.6–10.5 is an optimal medium for sorption of papain on chitosan. Bromelain is immobilized on a chitosan matrix under Tris-glycine buffer with pH 8.5 conditions.