Process for the separation of amino acids and their salts...

Details Process for the separation of amino acids and their salts... Process for the separation of amino acids and their salts...

1999-03-10

2001-01-09

Geist, Gary (Department: 1623)

Liquid purification or separation

Processes

Liquid/liquid solvent or colloidal extraction or diffusing...

C210S639000, C562S554000

Reexamination Certificate

active

06171501

ABSTRACT:

The present invention relates to a process for the separation of amino acids and their salts from impurities contained in an aqueous solution containing the same.
In recent years all over the world there has been a noticeable growth of amino acid utilization. Amino acids find their commercial application in human food, animal feed additives and in the pharmaceutical field. They are also used as intermediates for syntheses in special chemicals like synthetic sweeteners, chelating agents and pharmaceutical peptides (see e.g. Maui K. N., Chiao G. C., Chlauda F. P. “Recovery of Carboxylic and Amino Acids via Membrane Water Splitting”, AICHE Annual Meeting in Los Angeles, Calif. (1991); and Wen Shiuh Kuo, Been Huang Chiang “Recovery of Glutamic Acid from Fermentation Broth by Membrane Processing”, J. of Food Sci. Vol. 52, No. 5, p. 1401, (1987)).
Most amino acids are industrially produced by fermentation (see e.g. Aika K. Chibata I., Nakayama K., Takinami K., Yamada H. “Biotechnology of Amino Acids Production” Progr. Ind. Micr., Vol. 24 p. xxi, (1986)). These fermentation liquors are very complex and contain a great amount of fermentation byproducts, which increase the complexity and the cost of amino acid recovery and purification. These costs may reach up to 20% of the total production cost (See e.g. Yagodin G. A., Yrtov E. V., Golubcov A. S. “Liquid Membrane Extraction of Amino Acids” ISEC'86, Vol. III, p. 685, (1986)).
At present, a succession of filtrations, crystallization and redissolution, complicated ion-exchange steps and numerous steps of concentration are necessary (see e.g. Dablay P., Minier M., Renon H. “Separation of L-Valine from Fermentation Broths Using a Supported liquid Membrane”, Biotech. and Bioeng., Vol. 35, p. 123, (1990)). In many of the separations chemical energy application as a driving force results in consumption of reagents and in production of by-product salts of low or negative value. In search of more simple and less expensive way of amino acid separation from fermentation broth, liquid-liquid extraction was suggested. This separation method is based on amino acid properties to change the ionic charge depending on pH of the media (see e.g. Itoh H., Thien M. P., Wang D. I. C. “A Liquid Emulsion Membrane Process for the Separation of Amino Acids” Biotech. and Bioeng., Vol. 35, p. 853 (1990)).
Bearing amino and carboxylic groups, amino acids can be readily turned into cations, anions or zwitterions through pH changes as described by Morrison R. T., Boyd R. N. “Organic Chemistry” PP. 1136-1137, Boston, (1975)., and in accordance with the following reaction scheme:
For phenylalanine, for example, pKa=1.83 pl=5.48 and pKa
2
=9.15, wherein pl is the isoelectric point
Therefore, amino acids can exist as cations or anions or zwitterions. Two types of extractants acting as ion exchangers have been reported to be applicable in amino acid extraction systems (see e.g. Itoh I., Thien M. P., Hatton T. A., Wang D. I. C. “A Liquid Emulsion membrane Process for the Separation of Amino Acids” Biotech. and Bioeng. Vol. 35 pp. 853-854, (1990)). The first one is positively charge lipophilic extractant, such as Aliquat 336, a quatemary ammonium salt. The second one is a negatively charged extractant, such as di (2-ethyl-hexyl)phosphoric acid (D2EHPA), a lipophilic acid. Both ionic extractants are complexed with counter ions to maintain electro-neutrality in the apolar organic phase. These counter ions can be exchanged with charged amino acid solute of the same charge at the aqueous phase/organic interphase by an interfacial ion-exchange reaction to form an extractant amino acid complex The newly formed complex then diffuses across the organic phase. The amino acid containing organic phase can be stripped by an aqueous solution of an electrolyte, an acid or a base. At the stripping phase/organic interphase another ion exchange reaction takes place. The counter-ion in the stripping phase is exchanged for the amino acid which is then released into the stripping phase.
For Phe (phenylalanine) extraction from synthetic aqueous solution (see e.g. Haensel R., Halwachs W., Schugerl K. “Reactive Extraction of I,d-Phenylalanine with Tri-Octyl-Methyl-Ammonium Chloride (TOMAC) as a Carrier-III Equilibrium and Mass Transfer Investigations” Chem. Eng. Sci., Vol. 41, No. 7., pp. 1812-1813 (1986)) Phe was transformed into an anion by addition of NaOH to achieve equilibrium pH=11. The initial concentration of Phe was C
in
=16.9 g/l. The extractant, 2.5 M TOMAC (tri-octylmethylammonium chloride) in xylene, was taken with phase ration 1:1. The extraction coefficient was K=5.2 and the extraction proceeded according to the following reaction:
NH
2
CHRCOO
−
Na
+
+R
4
N
+
Cl
−
=NH
2
CHRCOO
−
NR
4
+
+NaCl
It was also shown that Trp (Tryptophane) extraction by 0.15 M TOMAC in xylene is more efficient than Tyr (Tyrosine) extraction by the same extractant. (The tests were made in single amino acids systems). Initial aqueous amino acid solutions of nearly equal concentrations C
Trp
=10.2 g/l, C
Tyr
=9.05 g/l were treated with NaOH solution to obtain amino acid anions (pH=11). Extraction coefficients were K
Trp
=10, K
Tyr
=1.1 [10]. The extraction selectivity of Asp (Aspartic acid) and Arg (Arginine) in extraction by TOMAC was also studied at high pH (see e.g. Schugerl K., Degener W., “Gewinung Midermolekularer Organischer Verbindungen aus Komlexen Wasrigen Gemishen durch Extraction” Chem. -Ing. -Tech. Vol. 61, No. 10, p. 798 (1989)).
0.0726 M D2EHPA in benzene was used as cation exchanger in Phe extraction (see e.g. Teramoto M., Miyake Y., Matsuyama H., Nara H. “Extraction of amino acids with Organophosphorus Extractant” Solvent Extr., pp. 1803-1808, (1990)). At equilibrium pH=4.2 distribution coefficients were for
Phe 0.015
Trp 0.014
Val 0.005 (Valine)
Ala 0.006 (Alanine)
Gly 0.0004 (Glycine
Lys 1.41 (Lysine)
For industrial separation of several amino acids (Phe, Glu, Asp, Trip, Tyr, etc.) from their fermentation broths, quarternary ammonium extractants were suggested (see e.g. U.S. Pat. No. 4,661,606.)
Resins are other kinds of ion exchangers, studied for amino acid separation. Ion exchange resins are synthetic resins having a chemical structure based on a cross linked three-dimensional polymer molecule onto which functional groups such as sulfonic acid and quartemary ammonium are bound. Ion exchange reactions are carried out combined with a diffusion of counter ions out of the resin particles. The ion exchange mechanism is similar to that of extraction by liquid ion exchangers. For anion exchange of Glu (Glutamic acid), quaternary ammonium resin AV172p in OH
−
form with resin capacity of about 3 mg-equiv.g
−1
was taken (see e.g. Selemenev V. F., Oros G. Yu., Ogneva L. A., Trubetskich G. V., Chikin G. A. “Interaction of Glutamic Acid with the AV-17-2P Anion Exchanger.” Russ. J. of Phys. Chem., Vol. 58 (10), pp. 1531-1532, (1984)). Glu with initial concentration C
in
=7.46 g/l was converted into the anion form at initial pH=7.7. The distribution coefficient D was 1 with phase volume ratio V
solution
/V
resin
=400. In cation form (see e.g. Selemenev V. F., Miroshnikova Z. P., Ogveva L. A., Ermakova I. I., Kotova D. L., Oros G. Yu. “Absorption of Glutamic Acid by Sulphonic Ction Exchangers” Russ. J. of Phys. Chem., Vol. 59 (8), pp. 1178-1180) Glu was absorbed by a sulfonic acid Resin KY-2-8 with D=9.9. So, it is seen that equilibrium distribution coefficients of ion exchange by extraction and by resins are comparable and their values are close. Nevertheless extraction process has two important advantages over ion exchange resins: a) it is several times faster, and b) it does not entail dilutions due to sweetening off.
To shift the pH to an acidic [or basic] range one needs to add some acid [or base] into the solution and this leads to additional byproducts. Furthermore, at such a low (or hi

Affiliated with

Also associated with

Rating

Process for the separation of amino acids and their salts... does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Process for the separation of amino acids and their salts..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for the separation of amino acids and their salts... will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2557391