Covalent binding is an enzyme immobilization technique that involves connecting enzymes with support materials such as agarose, porous silica, or polyacrylamide, via strong, highly stable linkages. 

Advantages of Covalent Binding:

• Provides a strong binding force between an enzyme and a carrier
• Enhances stereospecificity of the enzymes so they are more stable
• No leaking enzymes so sufficient enzymes are recovered to be reused
• The process is not affected by ionic strength or pH
• Is a straightforward process
• Enhanced selectivity and potency, and prolonged duration of action offers multiple advantages for pharmacological applications