Isolation of natural L-β-3-indolylalanine and enrichment of natural aliphatic amino acid mixtures with natural L-β-3-indolylalanine

A process for isolating substantially pure L-β-3-indolylalanine (L-β-3) from a source of amino acids including L-β-3, the process comprising:

• contacting a porous container containing a hydrophobic substance being attractive to aromatic amino acids and having substantially no attraction to aliphatic amino acids with an aqueous solution of the source of amino acids;
• agitating the aqueous solution and the porous container to allow a substantial portion of the L-β-3 to adsorb to the hydrophobic substance and thereby produce a first solution containing aliphatic amino acids;
• separating the porous container from the aqueous solution;
• contacting the porous container with an acidic solution to produce a second solution containing any L-phenylalanine and L-tyrosine displaced from the hydrophobic substance, wherein the acidic solution includes an acid selected from one or more of a group consisting of acetic acid, formic acid, propionic acid, butyric acid, isobutyric acid, and acids having a molecular weight no greater than 88.10 daltons and a Ka in the range of 1.77×10−4 and 1.34×10−5 at 25° C.;
• separating the porous container from the second solution;
• and
• contacting the porous container with a basic solution to displace L-β-3 from the hydrophobic substance and thereby produce a third solution containing L-β-3 , wherein the basic solution includes a base selected from one or more of a group consisting of ammonia, short chain aliphatic primary, secondary or tertiary amines, trimethylamine, triethylamine, (CH3)2NH (C2H5NH, CH3NH2, CH2CH2NH2and bases having a molecular weight no greater than 101.19 daltons and a Kbin the range of 1.26×10−3 and 1.8×10−5 at 25° C.