Simultaneous extraction and purification of aloe polysaccharides and proteins using ionic liquid based aqueous two-phase system coupled with dialysis membrane

In this paper, an ionic liquid based aqueous two-phase system (ILATPS) was employed in simultaneous extraction and purification of aloe polysaccharides (APS) and proteins by a single-step procedure. Parameters affecting the extraction efficiency were investigated in detail, such as type and concentration of phase-forming salt, temperature, pH, inorganic electrolyte, etc. tinder the optimal extraction conditions, APS can be extracted into salt-rich phase with high extraction efficiency, while majority proteins and other impurities were extracted into IL-rich phase. APS were further purified using a dialysis membrane to remove the salt and IL In addition, the monosaccharide constitutes of APS were analyzed by a HPLC method. The purity of the final product was demonstrated by a thermogravimetric analysis (TGA). IL in IL-rich phase was recycled by a simple solvent extraction method using dichloromethane. Compared with other liquid-liquid extraction, ILATPS is much simpler and "greener", it will open up new possibilities in the separation of other active ingredients in natural plants. (C) 2011 Elsevier B.V. All rights reserved.