Downstream processing of bio-products from fermentation broth is key step of all types of production industries and it is also cost and time consuming step as well. Aqueous two phase extraction is an ideal complementary technology over other conventional purification technologies due to its high selectivity and its economical cause as well. There are two kinds of Aqueous two phase system for protein/enzyme purification: polymer-polymer systems and polymer-salt systems. The nature of upper phase is hydrophobic with low density than the lower phase which is more denser and hydrophilic. The conventional techniques (chromatography, electrophoresis and precipitation) are considerably costly with low yields. Recently, aqueous two phase system have been an attractive technique for recovery of biological materials over other methods due to its suitable environmental condition such as high water content in both liquid phases (70-90%) with low interfacial tension between the two phases which results high mass transfer. Common polymer such as dextran and polyethylene glycol are used which have stabilizing effects on the biological activity and structure of proteins and enzymes. This technique requires relatively simple equipments with easy operation which is easy in scale-up and reliable too. The Aqueous two phase system can be performed by using mixture of aqueous solutions of two incompatible polymers or from a mixing solution of polymer and salt above critical concentration at equilibrium. Generally, the biomolecules are more evenly distributed between the phases and concerned by physico-chemical properties of biomolecule and theirs interaction. After adding desired solution of bio-products to the system, the extraction system should be mixed well till the resulted phases settle down. The partitioning of target product should be at upper layer whereas the undesirable particles such as cells, cell debris, other proteins and contaminants distribute to the lower separating phase. Specificity and effectiveness of aqueous two phase extraction can be further increased with the tagging of specific ligands specific to the desired protein/enzyme onto the polymer which results in a preferential binding of the protein/enzyme onto the polymer.

About Author / Additional Info:
Dr. Kirti Rani Sharma,
Assistant Professor (II),
Amity Institute of Biotechnology,
Amity University Uttar Pradesh, Noida
Sec-125, Gautam Buddha Nagar, Noida-201303 (UP), India.
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