Three phase partitioning of carbohydrate polymers: separation and purification of alginates

Three phase partitioning, a technique described for protein purification, has been employed for precipitation and purification of three different commercial preparations of alginates. Three phase partitioning works by the addition of /-butanol to aqueous solution of the polymer containing 20-30% ammonium sulphate (w/v). Three phases formed are: upper /-butanol layer, interfacial polymer precipitate and lower aqueous phase. In all the three cases, the process optimization was carried out by varying ammonium sulphate concentration, volume of tbutanol, alginate concentration and temperature. Fluorescence spectroscopy was used to show that repeated cycles of TPP also resulted in considerable reduction in polyphenol content of a crude alginate preparation.