Entrapping by Microencapsulation
The microencapsulation is another approach in enzyme immobilization by entrapping method. In this approach enzyme can be immobilized within microcapsules prepared from organic polymers, so that the enzyme can not escape, although low molecular weight substrates and products can enter and leave the capsule by diffusion through the membrane.

There are two general methods for preparing the membranous capsules for enzyme entrapping: (i) The membranes are prepared by the process of phase separation, which is similar to homogenization of water in oil. One phase is not miscible with the other but forms a droplet or coacervate with the .other phase, when mixed. The enzyme is entrapped within this droplet or coacervate. (ii) A water insoluble membrane is prepared by chemical polymerization and the enzyme is entrapped during this polymerization.

Spheres made up of semipermeable nylon or collodion membranes are often used for microencapsulation of an enzyme. Enzymes are also entrapped inside fibres of cellulose triacetate. These fibres may be packed in columns or woven into fabric.

The choice of the method to be employed for immobilization would certainly vary according to the enzyme involved and its application. Sufficient variation has been reported in the level of retention of enzyme activity on immobilization to different supports.