Membranes are used in bioreactors as selective barriers and sometimes also as a support/carrier matrix for enzyme immobilization. Such reactors are referred to as biocatalytic membrane reactors (BMRs). The immobilization of enzymes on membranes can be of two types: (i) nonspecific immobilization or (ii) specific immobilization (Fig. 1). Nonspecific immobilization is often random and proceeds through the numerous lysine residues on the protein. In this process, enzymatic activity is significantly decreased largely due to different orientations of the enzymes with respect to the membrane or to multiple point attachment which also renders the active site inaccessible for the substrates or sometimes results in complete denaturation of enzymes. Methods of nonspecific immobilization include adsorption, nonspecific covalent binding, entrapment, and encapsulation. Therefore, it is essential to develop methodologies for site-specific immobilization of the enzymes with the active (or binding)...