ABSTRACT
Downstream processing (DSP) is an integral part of the bioprocess industry. It usually consists of a series of separation and puri™cation steps, which ™nally aim to obtain the product at a desired level of puri™cation. The separation of biomolecules is often performed in batch mode by small-scale processes such as column chromatography, electrophoresis, salt, or solvent precipitation, for which scale-up poses a considerable problem, making them uneconomical unless the product is of high value. Liquid-liquid extraction (LLE) is a traditional chemical engineering unit operation for which the design and scale-up are already established. LLE is well known to operate continuously on a large scale with high throughput; unlike conventional chromatography, electrophoresis and precipitation techniques, ease of operation, and high ªexibility in its mode of operation are additional advantages (Treybal 1980). In recent years, LLE methods like aqueous two-phase extraction (ATPE) and reverse micellar extraction (RME) have been recognized as potential DSP techniques for bioactive components. Selective extraction of a target biomolecule from mixture/ crude extract into reverse micelles (RMs) can be achieved by varying extraction parameters (Harikrishna et al. 2002).
