The typical problems encountered in enzyme encapsulation through sol-gel process

such as too long gelation time

small gel pore size

low gel mechanical strength and so on

are briefly outlined. These problems can result in three dimensional conformation alteration and the active site shielding of the immobilized enzyme

the slow diffusion rate and the inaccessibility of substrate to the immobilized enzyme. The corresponding tentative solutions are presented herein: the gelation time can be considerably shortened by the appropriate screening of precursors and encapsulation conditions. The gel pore size can be enlarged and structure can be tailored with the introduction of chemical modifiers such as polyethylene glycol

glucose

cyclodextrin and other nonsurfactants. The mechanical strength of gel can be increased by the suitable drying process and drying control additives. In addition

other approaches are also mentioned to avoid enzyme denaturation

such as the special treatment during the aging stage and the suitable selection of buffer solution.