Table 2.

Characteristics of the various immobilization techniques.

Immobilization technique	Type of interaction	Strength of interaction	Advantages	Disadvantages
Entrapment	Ionic interactions, hydrophobic interactions, covalent bonds	weak/strong	No enzyme modification, ease of preparation, minimal loss of enzyme activity	Pose diffusion limitations to substrates and products, high enzyme leakage, difficult to implement at industrial level
Encapsulation	Ionic interactions, hydrophobic interactions	Weak	No enzyme modification, protection of the enzyme, minimal loss of enzyme activity, minimal enzyme leakage	Pose diffusion limitations to substrates and products, less concentration of enzyme
Adsorption	Epoxy groups hydrogen bonds, ionic interactions, hydrophobic interactions	Weak	No enzyme modification, simple and inexpensive reusability of the support, minimal diffusion limitations for substrates and products	May pose enzyme leakage, probable activity loss of enzyme, lower efficacy
Covalent binding	covalent bonds	strong	Strong and stable interactions, multipoint attachment, minimal enzyme leakage	Costly to prepare, may pose diffusion limitations for substrates and products, activity loss of enzymes, enzyme once denatured the support and enzyme are discarded
Cross-linking	covalent bonds	strong	No support needed, high strength of interactions	Poor stability, structural modification of enzyme by crosslinker leading to activity loss