Enzyme immobilization is a technique used to stabilize and reuse enzymes in various industrial and research applications. There are several methods of enzyme immobilization, each with unique advantages. Adsorption involves the physical binding of enzymes onto surfaces such as activated carbon or silica through weak forces like van der Waals forces and hydrogen bonding. This method is simple and cost-effective but may suffer from enzyme desorption. Covalent bonding entails the formation of strong covalent bonds between the enzyme and a support material, providing high stability and resistance to leaching, although it can sometimes affect the enzyme’s active site. Entrapment involves encapsulating enzymes within a network of polymers like alginate or polyacrylamide gels, allowing substrate diffusion while retaining the enzyme. This method maintains enzyme activity but can limit substrate access. Encapsulation, similar to entrapment, involves enclosing enzymes in a semi-permeable membrane, protecting them from external conditions while permitting substrate and product passage. Lastly, cross-linking involves the use of bifunctional agents to form intermolecular links between enzyme molecules, creating insoluble enzyme aggregates that can be used directly. This method offers high enzyme loading and stability but can be challenging to control and optimize. Each method has specific applications depending on the desired properties and constraints of the enzymatic process.