Abstract: The invention provides a process for the separation of amino acids and their salts from impurities contained in an aqueous feed solution containing the same, the process comprising: a) bringing the feed solution into contact with a substantially immiscible extractant phase comprising an amine and an acid, both of which are substantially water immiscible in both free and salt forms, to extract amino acid and salts thereof in the phase, wherein the extraction is carried out while the feed solution is within two pH units of the initial pH of the feed solution; and b) backwashing the extractant phase with a substantially neutral aqueous system to recover substantially all of the extracted amino acid and the extracted salts thereof.

Abstract: A supported polyionic hydrogel containing biologically active material is epared by impregnating into a porous support material a solution of anionic polysaccharide, a solution of cationic polysaccharide and a biologically active material. The anionic polysaccharide and the cationic polysaccharide react with each other to form a hydrogel containing the biologically active material. The hydrogel may be dried such as by lyophilization. The biologically active material can be in either polysaccharide solution or in another solution impregnated into the porous support material. A paper material or a textile material may be used as the porous support material. Preferably, the anionic polysaccharide is xanthan, dicarboxystarch or dicarboxycellulose and the cationic polysaccharide is chitosan. Especially preferred is a hydrogel formed from xanthan and chitosan.