Immobilization via Chemical Methods — Which description defines the chemical immobilization technique?

Introduction:
Immobilization strategies fall into physical and chemical categories. Chemical methods form covalent bonds between functional groups on the biomolecule and reactive groups on the carrier, yielding robust attachments with low leaching compared with simple adsorption.

Given Data / Assumptions:

• Reactive chemistries include aldehydes, epoxies, carbodiimides with NHS activation, and others.
• Target residues include amino, carboxyl, sulfhydryl, hydroxyl, and imidazole-bearing side chains.
• Reaction conditions preserve biomolecule activity.

Concept / Approach:

By forming covalent linkages, chemical immobilization provides strong, often irreversible binding that resists washout in continuous operation. Compared to non-covalent adsorption (physical method) or purely ionic interactions, covalent coupling better withstands changes in pH, ionic strength, and solvent composition, making it a preferred approach for stable industrial biocatalysts.

Step-by-Step Solution:

Verification / Alternative check:

Carrier activation protocols (e.g., aldehyde-agarose, epoxy-silica) exemplify covalent chemical immobilization used widely in practice.

Why Other Options Are Wrong:

B, D, and E describe non-covalent or physical methods. C is ambiguous and does not define the chemical pathway.

Common Pitfalls:

Over-activation can lead to nonspecific coupling and activity loss; optimize pH, time, and spacer length.

Final Answer:

It relies primarily on covalent bond formation between enzyme (or cell surface groups) and the support.