Introduction

Bioseparation is a critical step in biotechnology and biochemical engineering, where the goal is to isolate and purify biological products such as proteins, enzymes, or metabolites. Many bioseparation methods rely on partitioning—the distribution of a compound between two phases. However, not all separation techniques work on this principle.

Let’s explore which of the given techniques does not use partition-based separation.

What is Partition-Based Bioseparation?

Partitioning involves the distribution of molecules between two immiscible phases (typically liquid-liquid or solid-liquid) based on their solubility or affinity. Common partition-based techniques include:

• Solvent Extraction: Separation based on differential solubility in aqueous vs. organic solvents.

• Salting Out: Proteins precipitate by differential solubility in high salt concentration—a form of phase separation.

• Adsorption Chromatography: Molecules partition between mobile and stationary phases based on interactions like hydrophobicity or polarity.

The Exception: Electrodialysis

Electrodialysis is not a partition-based bioseparation technique. It operates on electrokinetic principles, where ions are separated through ion-exchange membranes under the influence of an electric field. The movement of ions is governed by charge and size—not by partition between two phases.

Comparison Table

Conclusion

Among the listed options, electrodialysis is the only method not based on partitioning. It separates ions based on their movement through membranes under an electric field rather than differential solubility between phases.

Correct Answer:
2. Electrodialysis