abstract |
Desired amino acids, e.g., phenylalanine, arginine, leucine, isoleucine, valine and/or histidine, are selectively countercurrently extracted from more complex, essentially cystine-free solutions of a plurality of amino acids, utilizing an organic phosphorus acid extractant, advantageously in solution in at least one alcohol, ether, ketone and/or aliphatic hydrocarbon. |