JPS61178952A - Method for purifying valine - Google Patents

Abstract

PURPOSE:To obtain the titled compound useful as an amino acid in high yield, by purifying impurities consisting essentially of isoleucine and/or leucine contaminating valine with a nonpolar porous synthetic adsorbent by simple procedures. CONSTITUTION:Impurities, contaminating valine, and consisting essentially of isoleucine and/or leucine are purified and removed. In the process,a nonpolar porous synthetic adsorbent, e.g. Diaion HP 20, SP 207 (manufactured by Mitsubishi Chemical Industried Ltd.) or XAD-4 or XAD-2000 (manufactured by Rohm and Haas Co.) is used to purify the valine. The above-mentioned method may be carried out by the batch or column method, but preferably the column method is used. The amount of the adsorbent to be used in the above-mentioned method is about 3-4 times based on the amount of an aqueous solution in about 30% concentration. The amount of the adsorbent may be smaller with decreasing concentration of the valine.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing valine, and more particularly to a method for removing impurities mainly composed of isoleucine and/or leucine contaminating phosphorus.

One method for producing valine by fermentation is a fermentation method using glucose as the main raw material, and the same can be said about iturin as an impurity in the valine crystals obtained by this method.

Most of these impurity amino acids can be removed by conventional methods such as ion exchange resin or recrystallization, but isoleucine and leucine are particularly difficult to remove.

In general, valine, isoleucine, and leucine have a common structural feature of 5Xt on the branch side, and therefore have very similar physical and chemical properties, making it difficult to separate them from each other. These mutual separation methods include a method using copper and cobalt complexes of these amino acids, a separation method using an aromatic sulfonate as a precipitant (Japanese Patent Application Laid-Open No. 16450/1983), and a sulfate method (
JP-A-56-51440), etc., but there are problems in that they form toxic complexes, that recrystallization must be repeated many times to recover the precipitant, and that they use concentrated sulfuric acid. .

As a result of intensive research, the present inventor has developed a method for separating and refining extremely pure valine from valine contaminated with impurities mainly consisting of isoleucine and/or leucine. The present invention has been completed by discovering that valine can be purified in high yield with a very simple procedure by treating it with K.

The amino acid of the present invention may be an optically active form or a racemic form.

Although the purification method of the present invention may be carried out by a patch method, it is preferably carried out by a column method. In the column type, after passing a valine aqueous solution containing isoleucine and/or leucine,
There is a chromatography method in which the water is eluted using water, etc., and a method in which the water is passed through until the water-soluble soft isoleucine and/or leucine breaks through, but the chromatography method is more effective because the amount of valine per adsorbent is It is advantageous in that the amount of liquid passed through, that is, the valine treatment device is large. Balin and Irosoishi/,
Although there is a notable difference in the adsorption power of isoleucine and leucine to adsorbents, the adsorption power of isoleucine and leucine to adsorbents is not so large.

For example, by filling a column with a non-polar porous synthetic adsorbent,
This can be carried out by injecting an aqueous solution of valine contaminated with isoleucine, leucine, etc. into the upper part of the column, and then flowing a suitable solvent to sequentially elute the amino acids.

The Paris/aqueous solution referred to in the present invention includes a valine fermentation broth, a solution of crude crystals obtained from the broth, etc., but it also includes valine contaminated with isoleucine and/or leucine and other impurities. The method of the present invention can be applied to any aqueous solution containing the above.

A method for removing valine, etc. from isoleucine using a non-polar synthetic adsorbent and utilizing the difference in the adsorption power of amino acids to the same adsorbent is already known (Japanese Patent Laid-Open No. 54-5551).
9), there is no method for removing isoleucine and/or leucine from valine.

By the way, the inventor of the present invention conducted a repeat of the method disclosed in JP-A-54-55519, and found that when the amino acids adsorbed on the non-polar synthetic adsorbent were eluted using water, for example, valine etc. were eluted first, and then valine etc. It was discovered that the breakthrough points of valine and isoleucine were almost the same, and only isoleucine was obtained after the elution of valine was completed. Therefore, this method is good for purifying isoleucine with a low contamination rate of halogen, but is good for purifying isoleucine with a high contamination rate of valine.
The disadvantage is that the yield of isoleucine is reduced.

According to the present inventor's knowledge that the breakthrough points of valine and isoleucine are almost the same, conversely, when trying to remove isoleucine from paris containing isoleucine as an impurity using the same method, isoleucine It is thought that the valine fraction is obtained only after the elution is completed, but the breakthrough points of the two are surprisingly different, depending on the isoleucine content, the volume of the aqueous solution, and the type of adsorbent. It was found that isoleucine was eluted first, and after that elution was completed, isoleucine was eluted, and a fraction containing only isoleucine was obtained.

In other words, the present inventors have discovered that this nonpolar synthetic adsorbent is characterized in that its extrusion and naternity vary depending on the amino acid ratio of the solution that is passed through it. For example, 1 to 5 tons of valine
When an isoleucine solution containing iI (versus isoleucine) was passed through, both amino acids were eluted almost simultaneously and no separation was observed, whereas inoleucine and/or leucine was eluted at 1 to 5 times (versus aZ IJ). When a solution containing valine is passed through, valine elutes first, then isoleucine,
It was found that leucine elutes in that order and has extremely good separation from valine. If the isoleucine and/or leucine content in the valine solution is 5% or less (relative to valine), separation is good, and if it is 2% or less, complete pressure separation from valine is possible.

A water silica solution with a concentration of up to about 30% is convenient for separation and nI production, and acidic solutions have better separation properties.

The non-polar porous synthetic adsorbent used in the present invention is composed of styrene and divinylbenzene, and is made of Ashi, Diaion HP 20. SP 207 (manufactured by Mitsubishi Chemical Corporation), XAD
-4, XAD-2000, r, ,t;yite58
61 (manufactured by 0-A and Haas), Repuacit QC1
031 (manufactured by Bayer AG) can be used. Among these, SP 207 and XAD-2000 have the best separation performance.

In the case of an aqueous solution with a valine concentration of about 30%, it is sufficient to use an amount of adsorbent that is about 3 to 4 times that amount. If the valine concentration is reduced, the amount of adsorbent 9 may be even smaller.

As the elution solvent, water, ammonia, an alkali such as sodium hydroxide, or an acid such as salt e can be used, but the best separation results can be obtained when water is used.

There is no particular restriction on the operating temperature, as long as it is within the heat resistance temperature of the non-polar synthetic adsorbent.

There are no particular restrictions on the liquid passing rate and elution rate (SV), and they may be within the usual range of 0.5 to 4.

Any conventional method may be used to regenerate the non-polar porous synthetic adsorbent.

i.e. acetone, sodium hydroxide, isopropyl 7
Can be regenerated with alcohol, etc. or a mixture thereof.

Example I L-valine 100#, L-isoleucine 2I.

Column filled with 5P207t-2000a+l (φ8crnXIH50cm) Ic SV
= 1, elution 2 was performed in addition to the liquid flow and water drainage. L-valine was eluted first, followed by L-isoleucine and L-leucine.

Fractions of eluate 111.6 to 81 were collected and 1.
6-411: main fraction, 4,21-81 were made sub-fraction. The main fraction contained only L-valine, and the sub-fraction contained no L-valine and only L-isoleucine and L-leucine.

By concentrating and crystallizing the main fraction, pure L-parin crystals containing no L-isoleucine or L-leucine were obtained. 90JiF, yield 90%.

Example 2 L-valine 11.9. L-isoleucine, L-leucine t each 0.125. Column (φ8crn :
Elution was performed from 73 [SV = 1] after ff.

L-valine is eluted first, followed by L-isoleucine,
L-leucine was eluted.

A volume of eluate of 1.2 to 8j was collected, of which 1.2 to 2.
8! All gold main fractions, 3) to 81 all sub fractions.

The main fraction was mostly L-valine, and the sub-fraction contained L-leucine and L-isoleucine.

Example 3 L-valine 100.9% L-isoleucine 1.9°L-
The solution was passed through a column (φ8c!nxH50crn) filled with 2000d of 300diSP 207, a solution of leucine 11 dissolved in 7% NOH and 50011j, at 5V=2, followed by elution with 0.2t NaOH. L-valine was eluted first, followed by L-isoleucine and L-leucine.

Fractions of eluate fi 1.6 to fi 5.21 were collected, with fi 1,6 to fi 3.2j being the main fraction and fi 3.4 to fi 5.2j being the sub fraction.

The main fraction is almost exclusively L-valine, with 85 g of L-valine (total 0.02 g of L-isoleucine per valine,
The sub-fraction contained L-valine, L-isoleucine, and L-leucine.

Example 4 L-14su7100F%L-glycine 9.51%L-
Glutamic acid 1.5#, L-alanine 3J, L-isoleucine II% L-isoleucine I! 1, L-valine crude crystals obtained from L-valinepros containing 1 g of L-IJ gin
% Dissolved in HC2500d, SP 207t-200
9d filled force 5 A (φ8 (7FIXH50 ports)
Elution was carried out by draining water at VCSV=1. L-glycine, L-glutamic acid, L-lysine, and L-alanine were eluted first, followed by L-valine, followed by L-(soloucine and L-leucine).

The eluate volume 1.4-21 is the sub-fraction part (1), and the eluate volume 2.2-21 is the sub-fraction part (1).
3.61 was defined as the gold main fraction, and 4 to 81 were defined as the sub-fraction (2).

The first sub-fraction (1) contained 60 units of L-glycine, L-glutamic acid, L-alanine, and L-lysine contained in the crude crystals of L-valine. The main fraction contained 40% of the amino acid residue and L-valine. The sub-fraction (2) contains L-iso-leucine and L
- Contains only leucine.

After adjusting the main fraction to -4 with NaOH, concentrating and crystallizing, and washing with water, it is extremely pure, containing no L-isoleucine or L-leucine and less than 2% (vs. glin) of other amino acids. A high L-i41J crystal was obtained.

80g Yield 80cm.

Patent issued by Ajinomoto Co., Inc.

Claims (1)

[Claims] A method for purifying valine, which comprises purifying valine using a non-polar porous synthetic adsorbent when purifying and removing impurities mainly consisting of isoleucine and/or leucine contaminating valine.