Amino acid separation process

905,584. Separating amino-acids by electrodialysis. ARMOUR & CO. Sept. 20, 1960 [Sept. 21, 1959], No. 32352/60. Class 41. Amino-acids are separated by electro-dialysis, in which the mixture is introduced into a compartment of a multi-compartment cell, bounded by an anionic permeable membrane and a cationic permeable membrane, adjusting the pH of the mixture to the iso-electric point of one acid to be retained, the others moving to the anode and cathode. Preferably the multi-compartment cell is tubular in shape, with circular diaphragms and electrodes. The pH values of anolyte and catholyte compartments are respectively higher and lower than that of the central compartment. In the case of a mixture of two only of amino acids, the mixture may be introduced directly into either the cathode or anode compartment at a suitable pH value, the central mixture compartment being then unnecessary. In a mixture of 3 or more acids, the pH values may be adjusted to (1) central compartment 5.5 to 6; (2) anode compartment 8 to 9; (3) cathode compartment 1 to 3. In examples, the mixtures separated are: histidine, lysine, arginine with traces of glutamic and aspartic acids ; hydrolysates of proteins are also referred to. A potential of about 15 volts is applied.