JP2007320918A - Method for producing amino acid - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To produce an amino acid under simple conditions without using a natural substance. <P>SOLUTION: The amino acid is produced as follows. An aqueous solution for a reaction containing a mixed valence iron complex having divalent iron and trivalent iron, e.g. iron (III)iron(II) chloride and an organic acid e.g. acetic acid, citric acid, an amino acid and malic acid is brought into contact with seawater salts, e.g, at least one selected from the group consisting of ammonium salts, magnesium salts, calcium salts and sodium salts and formaldehyde and stirring is carried out, e.g. at 20°C. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing an amino acid, and more particularly to a method for producing an amino acid using a non-biological technique.

Amino acids are basic compounds that constitute proteins that are important as biological components. In general, amino acids are obtained by a chemical method by hydrolyzing a protein with an enzyme or the like, or a biological method using gene expression using microorganisms such as E. coli.
On the other hand, as a method for synthesizing amino acids from inorganic substances, in addition to chemical synthesis, there is a method for generating peptides from carbonic acid and ammonia by modeling the state of the deep sea and hot springs where many sulfides exist (non-patented). Reference 1). In addition, there is a method for producing an amino acid by applying thermal energy or shock wave energy in contact with graphite, water, a nitrogen source, an iron group fiber metal, and the like as carbon atoms (Patent Document 1).
JP 2005-281300 A Marine Chemistry, Vol. 30, 1990, p. 179

However, it is difficult to obtain amino acids that are not in the system by the technique using natural products. Further, the method described in Non-Patent Document 1 has a problem that it is necessary to give thermal energy or a great impact, and it is difficult to proceed the reaction mildly, and there is a problem in simplicity. In the described method, a high temperature treatment at 200 ° C. or higher requires a shock wave.
Accordingly, an object of the present invention is to provide a method for producing an amino acid, which can easily produce an amino acid without using a natural product.

  The amino acid production method of the present invention is characterized in that an amino acid is synthesized by bringing a reaction aqueous solution containing a mixed valence iron complex having divalent iron and trivalent iron and an organic acid into contact with sea salt and formaldehyde. Yes.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the amino acid which can manufacture an amino acid simply, without using a natural product can be provided.

The amino acid production method of the present invention is characterized in that an amino acid is synthesized by bringing a reaction aqueous solution containing a mixed valence iron complex having divalent iron and trivalent iron and an organic acid into contact with sea salt and formaldehyde. Yes.
In the present invention, the reaction aqueous solution containing the mixed valence iron complex having divalent iron and trivalent iron and the organic acid is brought into contact with sea salt and formaldehyde, so that the electrons are stably stabilized under acidic conditions. As a result, amino acids can be produced under simple conditions without using natural products.
In particular, in the present invention, not only the same amino acid as the amino acid contained in the reaction aqueous solution can be produced, but also an amino acid not contained in the reaction aqueous solution can be newly produced.

The aqueous solution for reaction can be prepared by dissolving the mixed valence iron complex and the organic acid in water.
The mixed valence iron complex having divalent iron and trivalent iron used here is a water-soluble mixed valence iron complex in which divalent iron and trivalent iron are mixed, and iron (III) iron halide. (II) can be mentioned. Examples of the iron halide (III) iron (II) include iron chloride (III) iron (II), iron bromide (III) iron (II), iron iodide (III) iron (II) and the like. . Of these, iron (III) iron (II) chloride is preferred from the viewpoint of improving the electron absorption reactivity.
When preparing an aqueous solution for reaction, a mixed valence complex aqueous solution can be prepared by dissolving iron (III) chloride (II) in water. The amount of the mixed valence iron complex in the mixed valence aqueous solution is 0.1 mg / L to 0.4 mg / L, preferably 0.1 mg / L to 0.4 mg / L from the viewpoint of improving the reactivity, and the reactivity. From the viewpoint of improving the ratio, it is preferably 0.2 mg / L to 0.3 mg / L, more preferably 0.3 mg / L.

  The organic acid contained in the aqueous solution for reaction is not particularly limited as long as it has a carbonyl group, and examples thereof include acetic acid, amino acid, citric acid, malic acid, oxaloacetic acid, and derivatives thereof. Among these, from the viewpoint of environmental affinity and ease of preparation, it is preferably at least one selected from the group consisting of acetic acid, amino acid, citric acid and malic acid, from acetic acid, citric acid and malic acid. More preferably, it contains at least one selected from the group consisting of all of acetic acid, citric acid and malic acid. The organic acid only needs to be present in the reaction aqueous solution at a concentration capable of imparting reducibility at the same time as lowering the pH. In order to efficiently impart the reducibility necessary for amino acid production, The amount of the organic acid can be at least 500 mg / L, preferably 5000 mg / L to 10000 mg / L.

  Examples of the amino acid include serine, aspartic acid, glycine, L-alanine, glutamic acid, cytosine, γ-aminobutyric acid, urea, leucine, isoleucine, and phenylalanine. The amino acid content in the aqueous reaction solution is not particularly limited, but can be 2 to 9 mmol / L in total.

In addition to these components, other components can also be added. Such components, copper ions, vitamins such as vitamin C and vitamin B _6, can be mentioned dietary fiber. Examples of such an aqueous solution for reaction include FFC pyrogen (registered trademark, hereinafter the same; Akatsuka Co., Ltd.). When this FFC pyrogen is used as the above aqueous solution for reaction, it may be diluted with water to a concentration of 50% by mass to 100% by mass and 90% by mass to 100% by mass from the viewpoint of improving the reaction activity.

The sea salt used in the present invention may be any salt found in sea water, but particularly refers to inorganic salts found in hot water near the hot water outlet, ammonium salt, magnesium salt, calcium salt, sodium A salt can be mentioned, and any of these or a combination of two or more thereof can be used, but it is most preferable to include all of them from the viewpoint of reactivity. These seawater salts are preferably at least one selected from the group consisting of ammonium carbonate, formaldehyde, magnesium sulfide, calcium chloride, and sodium sulfide from the viewpoint of amino acid synthesis efficiency, and include all of these. Most preferred.
These seawater salts are preferably 2 to 30% by mass, more preferably 5 to 25% by mass, based on the amino acid synthesis efficiency, based on the total volume of the reaction aqueous solution. If it is 2% by mass or more, a sufficient amount of amino acid can be synthesized in the reaction system, and if it is less than 30% by mass, an amino acid can be synthesized efficiently.

  Further, the formaldehyde used in the present invention can be brought into contact with the reaction aqueous solution so as to be 0.2% by volume to 10% by volume with respect to the total volume of the reaction aqueous solution. It is preferable to contact at 2% by volume to 5% by volume. If the content is 0.2% by volume or more, the expected effect can be expected. On the other hand, by setting it to less than 10% by volume, the reaction rate can be adjusted to an appropriate range.

  When bringing the aqueous reaction solution of the present invention into contact with the above-described seawater salt and formaldehyde, it is preferable to bring the seawater salt into contact with the aqueous reaction solution prior to formaldehyde from the viewpoint of improving reactivity. At this time, since carbon dioxide gas is generated in the reaction system, it is preferable to use a system in consideration of an increase in atmospheric pressure.

  Moreover, it is preferable to perform the said contact under high purity inert gas. As a result, it is possible to avoid mixing impurities from outside and to evaluate the synthesized product separately from exogenous impurities. Examples of the inert gas include argon, nitrogen and the like. Among these, argon having low reactivity is preferable. Under an inert gas, the reaction can proceed under mild conditions at room temperature.

  The pH of the aqueous reaction solution may be any pH that does not impair the ability to synthesize amino acids, and is preferably 5.5 or less, more preferably 3 or less from the viewpoint of reaction efficiency. The reaction temperature may be room temperature, preferably 15 to 30 ° C. In addition, the reaction time may be sufficient for amino acid production, for example, from 24 to 72 hours, preferably from 24 to 50 hours from the viewpoint of sufficiently performing the reaction and avoiding overreaction. Stirring may be performed using a commonly used device, for example, a rod-shaped magnetic stirrer (length 2 cm). The stirring speed is preferably, for example, 200 to 500 rpm for a rod-shaped magnetic stirrer having a length of 2 cm and 200 to 300 rpm from the viewpoint of controlling reactivity.

An amino acid is synthesized in the reaction system by the contact step described above. The amino acids obtained here include not only amino acids present in the aqueous reaction solution (referred to as “existing amino acids”) but also amino acids that are not present in the reaction system at the start of the reaction (referred to as “new amino acids”). In the case of an existing amino acid, it can be easily confirmed by obtaining more than the content in the reaction aqueous solution at the start of the reaction. For example, serine, aminobutyric acid and the like can be confirmed as existing amino acids produced.
On the other hand, as a new amino acid, it can be easily confirmed that it was not present at the start of the reaction by conducting a normal amino acid analysis. Examples of such novel amino acids include ornithine and beta alanine.

  Further, by continuing the reaction time within the above-mentioned range or extending, in addition to the production of amino acids, each amino acid can be dehydrated to form a peptide bond to form a polypeptide. The presence of this polypeptide can be confirmed visually by filing an insoluble substance, and can be confirmed by detecting a specific signal (for example, C = O) of the polypeptide using an infrared absorption spectrum.

  The polypeptide obtained by this method may have any molecular weight, and generally has a number average molecular weight of 10,000 to 15,000. The molecular weight of the polypeptide can be easily adjusted by adjusting the reaction time or adjusting the amount of inorganic salts and aldehyde to be dissolved.

  The amino acid and its polypeptide obtained by this amino acid production method can be easily detected in the form of a precipitate as a water-soluble or insoluble molecule in the reaction system, and can also be detected by high-performance liquid chromatography or the like. In this case, it can be easily purified by filtration, drying or the like. Identification of the obtained amino acid can be easily performed by using means usually used for amino acid identification, such as mass spectrometry.

Any amino acid can be produced as long as it is contained in the above amino acid, and the type of amino acid obtained is not fixed. This can be easily obtained by the present invention for any amino acid.
In addition, since a novel amino acid that is not contained in the reaction aqueous solution can be synthesized from an inorganic substance, a natural product containing the desired amino acid can be obtained without preparing it in advance.
Since the amino acid according to the present invention can be obtained as an aqueous solution, it can be used simply as it is, for example, it can be suitably used as a fertilizer.

  Examples of the present invention will be described below, but the present invention is not limited thereto. Further,% in the examples is based on weight (mass) unless otherwise specified.

[Example 1]
Properties of aqueous solution for reaction For the production of amino acids, about 9 mmol / L amino acid, about 1500 mg / L acetic acid, about 7000 mg / L citric acid, about 1500 mg / L malic acid, about 0.3 mg / L in total. A reaction aqueous solution containing an iron ion component and a copper ion component of about 0.001 mg / L was used.
For this aqueous solution for reaction, the composition components were determined using an electron spin resonance (ESR) apparatus (JEOL JES TE-200, manufactured by JEOL Ltd.) and an amino acid analyzer (JEOL JLC-300 Amino Acid Analyzer, manufactured by JEOL Ltd.). Analysis and further confirmation of electron donating properties. In the measurement by the electron spin resonance apparatus, water was used as a solvent, and measurement was performed at a liquid helium temperature (5 K) with a modulation of 100 KHz. A 500 μL sample was measured with an amino acid analyzer at room temperature. The result of the ESR measurement is shown in FIG.

Further, the electron donating property of the aqueous reaction solution according to this example was verified using tetrathiafulvalene (TTF). It is known that this TTF forms a charge transfer complex (CT) by forming a complex with an electron donor, and at this time, the band of the light absorption spectrum changes significantly.
The aqueous solution for reaction (sample 1) according to this example was added at 10 vol / vol% or 20 vol / vol% to the TTF tetrahydrofuran solution (2.3 × 10 ⁻⁵ M, sample 2). Samples 3 and 4 were designated. The light absorption spectrum was measured about the samples 1-4. The result of the light absorption spectrum is shown in FIG.

  Regarding the electron spin state of the aqueous solution for this reaction, as shown in FIG. 1, the ERS measurement shows a signal derived from iron which is a half-field resonance in the vicinity of 1500 mT, and is further derived from the spin of copper atoms in the vicinity of 3300 mT. Resonance was observed. Further, the hydrogen ion concentration was 2.7 or less at 20 ° C., and it was found that the aqueous solution for this reaction was a strong acid.

On the other hand, as shown in FIG. 2, sample 1 (solid line, only aqueous solution for reaction according to this example) and sample 2 (dashed line, tetrahydrofuran solution of TTF) both had an absorption maximum at 450 nm. In 3 and 4, an interaction occurred and the peak of the 450 nm absorption band decreased.
Sample 3 (one-dot chain line) and 4 (as compared with the two-dot chain line), in sample 3, the absorption near 350 nm decreased and the absorption near 300 nm also decreased, but the concentration of the aqueous solution for reaction according to this example Sample 4 having a high absorption increased overall as compared with Sample 3, and the peak intensity in the absorption band after about 340 nm increased again.From this, the aqueous reaction solution according to this example had an electron in TTF. It was found that a new complex was formed.
From the above, it becomes clear that the aqueous reaction solution of this example has a reducing action of donating electrons to a substance having a property of depriving electrons even though the aqueous solution has a pH of 3 or less. It was.

[Example 2]
Production of amino acid 20 mL of the aqueous reaction solution used in Example 1 is dissolved in 140 mL of distilled water. To this, 3.3 g of ammonium carbonate (NH ₄ HCO ₃ ) is slowly added, and then 2.52 g of magnesium sulfate (MgSO ₄ ) and 1.5 g of calcium chloride (CaCl ₂ ) are added. At this time, the generation of carbon dioxide gas is confirmed. Add 1.5 mL of formaldehyde (HCHO) while bubbles are occurring. Further, 1 g of sodium sulfate (NaSO ₄ ) is added, and this solution is stirred with a rod-shaped magnetic stirrer having a length of 2 cm. The reaction was carried out for 24 hours under an inert gas argon atmosphere.
The obtained aqueous solution was measured with an amino acid analyzer, and the amino acids contained in the solution were analyzed (amino acid analyzer, JEOL JLC-300 Amino Acid Analyzer). The result is shown in FIG. The upper part of FIG. 3 shows the amino acid analysis results of the aqueous reaction solution before the reaction, and the lower part of FIG. 3 shows the amino acid analysis results of the reaction system after the reaction.

As shown in FIG. 3, in the reaction system after the reaction, serine (SER) increased in relative value, glycine (GLY), alanine (ALA) decreased, and beta-alanine that did not exist in the system. It was confirmed that (B-ALA) and ornithine (L-Ornithine) were produced (lower part of FIG. 3). This means that two new amino acids were synthesized in the reaction system. The aqueous solution for reaction used in this example contains several types of amino acids as existing amino acids at the start of the reaction (the upper part of FIG. 3), and any of the detected amino acids is the main raw material for beta-alanine and ornithine. It is clear that this is a newly synthesized compound in this reaction system.
In the reaction system after the reaction, it was confirmed that the relative amount of serine was increased as compared with other existing amino acids. Therefore, it is clear that serine which is an existing amino acid is further produced in the reaction system by the reaction, and as a result, the relative value is increased.

  Furthermore, insoluble granular precipitates were also synthesized in the reaction system after the reaction. A polarized light micrograph of this insoluble precipitate is shown in FIG. This insoluble precipitate was subjected to molecular weight measurement [manufactured by JASCO Corporation, MULTI-340 (UV Detector), 880-PU (pump), ODA-80TM (column)] by gel permeation chromatography using tetrahydrofuran as a solvent. As a result, it was found to be a polymer having a number average molecular weight of 9200 in terms of standard polystyrene. In order to further investigate the composition of the insoluble precipitate, infrared absorption spectrum measurement was performed (HORIBA, FT-720). The results are shown in FIG.

As shown in FIG. 5, in the polymer after the reaction, the COOH signal (ν _COOH : 1730 cm ⁻¹ ) indicating the presence of an amino acid is small, while the signal indicating C═O (ν _C═O : 1650 cm ⁻¹ ) was detected. The broad signal (ν _OH ) spreading around 3400 cm ⁻¹ is that of the solvent.
This indicates that the obtained polymer contains a peptide bond and a polypeptide is formed in addition to the amino acid. Such a signal was not detected when an aqueous solution other than the aqueous reaction solution according to this example was used. Therefore, it is considered that amino acid synthesis and polypeptide formation are due to the acidic characteristics (pH = 2.7) and the reducing action of the aqueous reaction solution according to this example.

  As described above, according to the present invention, by bringing seawater salts and formaldehyde into contact with an aqueous solution for reaction containing a mixed valence iron complex having divalent iron and trivalent iron and an organic acid, existing amino acids and polyamino acids can be synthesized. Peptides can be easily produced in the reaction system.

It is a chart which shows the measurement result of the electron spin resonance (ESR) of the aqueous solution for reaction used in the Example of this invention. It is a chart which shows the result of the absorption spectrum measurement of the samples 1-4 concerning the Example of this invention. It is a chart which shows the result of the amino acid analysis of the aqueous solution for reaction concerning this example (upper stage) and the reaction system after reaction (lower stage). It is a polarizing microscope photograph image (a scale bar is 100 micrometers) of the insoluble polymer obtained by the present Example. It is a chart which shows the infrared absorption spectrum (broken line) of the aqueous solution for reaction concerning a present Example, and the infrared absorption spectrum (solid line) of the insoluble polymer obtained after reaction, respectively.

Claims (4)

  An amino acid production method comprising synthesizing an amino acid by bringing a reaction aqueous solution containing a mixed valence iron complex containing divalent iron and trivalent iron and an organic acid into contact with sea salt and formaldehyde.   The method according to claim 1, wherein the mixed-valence iron complex is iron (III) halide (II).   The production method according to claim 1 or 2, wherein the organic acid is at least one selected from the group consisting of acetic acid, amino acid, citric acid and malic acid.   The production method according to any one of claims 1 to 3, wherein the sea salt is at least one selected from the group consisting of an ammonium salt, a magnesium salt, a calcium salt, and a sodium salt.