Pepsin immobilization: Influence of carbon support functionalization

Among the matrices for enzyme immobilization, activated carbon has been standing out in immobilization processes due to its properties and to its characteristics that provide superficial modification by inserting new functional groups capable of binding the enzymes forming covalent bonds. In this study the effect of different modification methods of activated carbon (functionalization with genipin, metallization, metallization in the presence of chelating agent, and functionalization with glutaraldehyde) on efficiency of pepsin immobilization was evaluated. The effect of immobilization pH and the reaction medium on hydrolysis activity of bovine casein was also evaluated. The functionalization of activated carbon using iron ions allowed an immobilization capacity of 98.93 mg·g^-1, with immobilization efficiency greater than 99%, and enzyme activity of 2.30 U, which was higher than the other modifications, and closer to the enzyme in the native form activity (3.32 U). In general, the carbon surface modifications were responsible for forming more stable bonds between support and enzyme, improving its proteolytic activity (from 1.84 to 2.30 U) when compared to traditional immobilization methods by adsorption and covalent binding using glutaraldehyde (from 1.04 to 1.1 U).