Title of Invention: Method for preparing 5'-disodium guanylate heptahydrate crystals
technical field
[One]
The present invention relates to a method for preparing 5'-disodium guanylate heptahydrate crystals. More particularly, it relates to a method for obtaining 5'-disodium guanylate heptahydrate crystals without using an organic solvent by concentrated crystallization.
background
[2]
5'-disodium guanylate crystals are generally known in the form of amorphous, plate-shaped tetrahydrate and columnar heptahydrate. In the case of an amorphous form, it is difficult to separate, transport, and store solid-liquid, so the industrially used form is mainly heptahydrate.
[3]
[4]
A method for industrially obtaining the crystals uses a hydrophilic organic solvent such as methanol or ethanol, which is an alcohol-based anti-solvent.
[5]
[6]
As described above, in the crystallization method using an organic solvent, the hydrophilic organic solvent used is contained in the crystal and remains after the product is dried, thereby causing user anxiety. In addition, since it is necessary to obtain a high-purity organic solvent in the process of recovering the hydrophilic organic solvent used in the process, an investment cost for a distillation column, utility costs related thereto, and explosion-proof costs for the safety of workers occur.
[7]
[8]
Accordingly, the present inventors have conducted improvement experiments in order to solve the above disadvantages, and have found that 5'-disodium guanylate heptahydrate crystals can be obtained without using an organic solvent, and have completed the present invention. .
DETAILED DESCRIPTION OF THE INVENTION
technical challenge
[9]
One aspect comprises the steps of forming an amorphous solid in a mixed solution by mixing an aqueous salt solution and an aqueous 5'-guanylic acid solution; and adding crystal seeds to the mixed solution to form 5'-disodium guanylate heptahydrate crystals, wherein the step of adding the crystal seeds is 5'-guanylic acid performed while maintaining the temperature at 25 to 45°C A method for preparing disodium heptahydrate crystals is provided.
means of solving the problem
[10]
One aspect comprises the steps of forming an amorphous solid in a mixed solution by mixing an aqueous salt solution and an aqueous 5'-guanylic acid solution; and adding crystal seeds to the mixed solution to form 5'-disodium guanylate heptahydrate crystals, wherein the step of adding the crystal seeds is 5'-guanylic acid performed while maintaining the temperature at 25 to 45°C A method for preparing disodium heptahydrate crystals is provided.
[11]
[12]
In the method, the aqueous salt solution may have a pH of 7 to 10. The addition may be performed while maintaining the temperature of the mixed solution at 25 to 45°C.
[13]
The concentration of the salt in the aqueous salt solution may be any as long as it is mixed with the 5'-guanylic acid aqueous solution to form a mixed solution having a salt concentration of 160 to 360 g/L. For example, the aqueous salt solution may be 200 to 400 g/L aqueous salt solution.
[14]
[15]
The 5'-guanylic acid aqueous solution may be prepared by adding 5'-guanylic acid to water. The 5'-guanylic acid aqueous solution may be 50 to 400 g/L 5'-guanylic acid aqueous solution. The 5'-guanylic acid aqueous solution may include a salt, for example, 5'-guanylic acid disodium aqueous solution. The 5'-guanylic acid aqueous solution may include one obtained by culturing microorganisms. What is obtained by culturing the microorganism may be a supernatant obtained by removing cells from a culture containing 5'-guanylic acid. What is obtained by culturing the microorganism may be obtained by purification using ion exchange chromatography or activated carbon from the supernatant. Purification using activated carbon may include mixing activated carbon and a culture solution to bind impurities to activated carbon, and removing the activated carbon to which impurities are bound from a reactant.
[16]
[17]
In the method, mixing the 5'-guanylic acid aqueous solution may be performed until the concentration of the salt in the mixed solution becomes 160 to 360 g/L. Mixing the 5'-guanylic acid aqueous solution may be performed until the concentration of NaCl in the mixed solution becomes 160 to 360 g/L.
[18]
In the method, the forming of the amorphous solid may include drying the mixed solution so that the concentration of the salt is 160 to 360 g/L. Mixing the 5'-guanylic acid aqueous solution may be added in portions by dividing the aqueous solution. The addition may be dropwise. The addition may be performed for 1 to 1000 minutes. Mixing the 5'-guanylic acid aqueous solution may be performed while stirring.
[19]
[20]
As used herein, the term "amorphous solid" is a white solid that is not shaped like crystals and is randomly precipitated, floating in a solution, and is not transparent, irregular, and opaque when viewed under a microscope because it is amorphous. By drying this amorphous solid, it can be confirmed that it is an anhydrate when analyzing the hydrate.
[21]
[22]
In the above method, adding the crystal seeds may be performed while maintaining the temperature of the mixed solution at 25 to 45 °C. The crystal seeds may include 5'-disodium guanylate heptahydrate crystals. Adding the crystal seeds may be performed while stirring the reactor. Adding the crystal seeds may be adding the crystals in portions. The addition may be dropwise. The addition may be performed for 1 to 1000 minutes. The amount of crystal seeds to be added may be obtained by determining the weight of 5'-guanylate in a mixed solution of 5'-guanylic acid aqueous solution and salt aqueous solution, and this may be used as a basis for the added weight of crystal seeds. The amount of the added crystal seeds may be 0.1 to 5.5 parts by weight, or 0.1 to 5.0 parts by weight based on 100 parts by weight of the 5'-guanylate. The 5'-guanylate salt may be, for example, 5'-guanylate disodium.
[23]
[24]
The method may further comprise cooling the solution containing the formed crystals after the step of forming the 5'-disodium guanylate heptahydrate crystals. The cooling is to be carried out at 25 °C or less, for example, 4 to 25 °C, 4 to 20 °C, 4 to 15 °C, 4 to 10 °C, 10 to 25 °C, 15 to 25 °C, or 10 to 20 °C. can
[25]
[26]
The method may further comprise isolating the crystals from the solution containing the crystals formed after the step of forming the 5'-disodium guanylate heptahydrate crystals. The separation may be centrifugation or filtration. The centrifugation may be performed at 100 to 1000xg. The centrifugation may be performed for 1 to 30 minutes. The filtration may be using a filter of 0.22 to 200 μm.
[27]
[28]
In the method, the aqueous salt solution may be an aqueous solution of a metal salt. That is, the salt of the aqueous salt solution may be a metal salt. The metal salt may include an alkali metal salt. The alkali metal salt may be a sodium containing salt. The alkali metal salt may be NaCl, KCl, Na 2 CO 3 , NaHCO 3 , or Na 2 CO 3 .
[29]
[30]
One embodiment comprises the steps of mixing a 5'-guanylic acid aqueous solution with an aqueous salt solution so that the concentration of the salt in the mixed solution is 160 to 360 g/L to form an amorphous solid in the mixed solution; and adding crystal seeds to the mixed solution to form 5'-disodium guanylate heptahydrate crystals, as a method for producing 5'-disodium guanylate heptahydrate crystals, wherein the temperature of the mixed solution is 25 to 45 It may be a method that is ℃. The aqueous salt solution may be 200 to 400 g/L aqueous salt solution. The 5'-guanylic acid aqueous solution may be 50 to 400 g/L 5'-guanylic acid aqueous solution. The aqueous salt solution may have a pH of 7 to 10. The crystal seeds may be 5'-disodium guanylate heptahydrate crystals. The 5'-guanylic acid aqueous solution includes those obtained by culturing microorganisms. The 5'-guanylic acid aqueous solution may include a culture obtained by culturing microorganisms or a culture supernatant from which cells are removed, or 5'-guanylic acid purified therefrom. The microorganism may be one having the ability to produce 5'-guanylic acid. The amount of the added crystal seeds may be 0.1 to 5.5 parts by weight based on 100 parts by weight of 5'-guanylate formed in the mixed solution. The salt may be NaCl. The 5'-guanylate salt may be, for example, 5'-guanylate disodium.
[31]
[32]
One embodiment includes the steps of mixing an aqueous NaCl solution and an aqueous 5'-guanylic acid solution so that the concentration of the salt in the mixed solution is 160 to 360 g/L to form an amorphous solid in the mixed solution; And 0.1 to 5.5 parts by weight of 5'-disodium guanylate heptahydrate crystals were added to the mixed solution as crystal seeds based on 100 parts by weight of the 5'-guanylate formed in the mixed solution to obtain 5'-disodium guanylate heptahydrate crystals. As a method for producing a 5'-disodium guanylate heptahydrate crystal, comprising the step of forming, the temperature of the mixed solution may be a method of 25 to 45 ℃. The aqueous salt solution may be 200 to 400 g/L aqueous salt solution. The 5'-guanylic acid aqueous solution may be 50 to 400 g/L 5'-guanylic acid aqueous solution. The aqueous salt solution may have a pH of 7 to 10. The 5'-guanylic acid aqueous solution includes those obtained by culturing microorganisms. The 5'-guanylic acid aqueous solution may include a culture obtained by culturing microorganisms or a culture supernatant from which cells are removed, or 5'-guanylic acid purified therefrom. The microorganism may be one having the ability to produce 5'-guanylic acid. The amount of the added crystal seeds may be 0.1 to 5.5 parts by weight based on 100 parts by weight of the 5'-guanylate.
Effects of the Invention
[33]
According to the method for producing 5'-disodium guanylate heptahydrate crystals from 5'-guanylic acid aqueous solution according to an aspect, 5'-disodium guanylate heptahydrate crystals can be efficiently prepared from 5'-guanylic acid aqueous solution.
[34]
Specifically, according to the method for preparing 5'-disodium guanylate heptahydrate of the present invention, crystals of 5'-disodium guanylate heptahydrate can be obtained without adding an organic solvent. According to the manufacturing method of the present invention, it is more advantageous to the operator in terms of safety that may be caused by the organic solvent, and since the organic solvent does not remain in the final product, it may not cause the end user's anxiety about the harmfulness of the organic solvent. In addition, it is economical because the investment in explosion-proof equipment and equipment maintenance cost are reduced, or the investment and equipment cost of a distillation column that recovers the used organic solvent with high purity, and the utility cost used for process operation are reduced.
Brief description of the drawing
[35]
1 is a microscopic photograph of 5'-disodium guanylate heptahydrate crystals obtained according to Example 1. FIG.
[36]
FIG. 2 is a microscopic photograph of plate-shaped 5'-disodium guanylate tetrahydrate crystals obtained according to Comparative Example 2. FIG.
[37]
FIG. 3 is a microscopic photograph of 5'-disodium guanylate heptahydrate crystals obtained by using methanol, which is a hydrophilic organic solvent, according to Comparative Example 3. FIG.
Modes for carrying out the invention
[38]
Hereinafter, the present invention will be described in more detail through examples. However, these examples are for illustrative purposes only, and the scope of the present invention is not limited to these examples.
[39]
[40]
Example 1
[41]
In this Example, 5'-disodium guanylate heptahydrate crystals were formed from an aqueous solution of 5'-disodium guanylate without using an organic solvent, and this was separated.
[42]
[43]
In a 3L flask, 0.875 L of 380 g/L 5'-disodium guanylate aqueous solution was slowly added to 1 L of 300 g/L sodium chloride aqueous solution having a pH of 9 and a temperature of 40° C. over 30 minutes. As a result, an amorphous solid was formed in the mixed solution. In addition, the 5'-disodium guanylate is obtained by obtaining and purifying the 5'-guanylic acid-containing fermentation product through microbial fermentation itself. The pH of the sodium chloride 300 g/L aqueous solution was adjusted using 2 mL of a concentration of 50 (w/w)% NaOH. The amorphous solid was transformed into 5'-disodium guanylate heptahydrate crystals at a sodium chloride concentration of 160 g/L in the mixed solution.
[44]
[45]
While maintaining the temperature of the mixed solution of sodium chloride aqueous solution and 5'-disodium guanylate aqueous solution at 42°C, 5'-disodium guanylate heptahydrate crystals as crystallized seeds in the solution were compared to the weight of 5'-disodium guanylate formed in the mixed solution 1% by weight was added and incubated under the same conditions. After incubation, the amorphous solid transformed into columnar 5'-disodium guanylate heptahydrate within 1 hour. As a result, the mixed solution was in the form of a slurry containing crystals. The term "slurry" refers to a viscous suspension in which solid crystals and liquid are mixed. Hereinafter, the mixed solution containing crystals is also referred to as a crystal slurry.
[46]
[47]
This indicates that columnar 5'-disodium guanylate heptahydrate can be formed by incubating a mixed solution of sodium chloride aqueous solution and 5'-guanylate aqueous solution in the presence of 5'-disodium guanylate heptahydrate crystal seeds. This indicates that columnar 5'-disodium guanylate heptahydrate can be formed by incubation of the mixed solution without using an organic solvent. This is a significant effect that is unexpected for a person skilled in the art.
[48]
Next, from 1 hour after incubation, the temperature of the crystal slurry was gradually cooled naturally to 25° C. or less over two hours.
[49]
This crystal slurry was placed in a basket separator H-110F (KOKUSAN Co. Ltd., Japan) and centrifuged for 20 minutes at a bowl G-force of 340 xg. As a result of centrifugation, the supernatant was removed and a crystal slurry was obtained. From the obtained crystal slurry, 285 g of 5'-disodium guanylate heptahydrate crystals were obtained.
[50]
[51]
The H-110F centrifuge has a perforated basket installed therein, and the basket is connected to an external rotation supply. The perforated basket is made of polyamide multifilament fiber filter fabric, and the air permeability of the filter is 250 L/m 2 /s at 2 mbar. The filtered crystals were dried at room temperature for 24 hours.
[52]
[53]
The purity and concentration of the isolated 5'-disodium guanylate heptahydrate crystals were analyzed using HPLC. Specifically, 1.0 g of the dried 5'-disodium guanylate heptahydrate crystal and 5'-disodium guanylate heptahydrate standard crystal (Sigma, ≥99.0 (w/w)% (HPLC)) were dissolved in 1L of tertiary distilled water. Examples and standard solutions of 1.0 g/L each were prepared. The purity of 5'-disodium guanylate heptahydrate in the standard solution was confirmed through the certificate of the standard reagent manufacturer. Thereafter, the concentration of 5'-disodium guanylate in the standard product was calculated as 1.0000 g/L x [purity of the standard product].
[54]
[55]
5 uL of Example and Standard solutions were loaded onto the column in an Agilent 1260 Infinity Quaternary LC (Agilent Technology Inc.) system. The column is a Shiseido CAPCELL PAK C18 ACR (150mm x 4.6mm, 3um). Next, the absorbance at 254 nm for the eluate flowing out while flowing acetonitrile 2% (v/v)/phosphate buffer (pH 2.4) 98% (v/v) at a flow rate of 1 ml/min to the column is measured. did. The phosphate buffer contains 2 g/L of ammonium phosphate, 0.2 g/L of tetrabutyl ammonium phosphate, and 0.82 g/L of phosphoric acid. The temperature at this time was 35°C. This HPLC condition was also used to measure the 5'-GMP concentration in the filtrate. As a result, the purity was calculated according to the following formula.
[56]
[57]
Purity = 5'-GMP content / weight of total solids x 100
[58]
[59]
In addition, 5 uL of the solutions of Examples and Standards were placed in a rectangular cell of CARY 100 UV-VIS (Agilent Technology Inc.) and transmittance was measured at 420 nm.
[60]
[61]
As a result, the obtained crystal slurry was naturally dried at 25°C for 12 hours to obtain dried 5'-disodium guanylate heptahydrate crystals. The dried crystals had a residual moisture content of 23.6 (w/v)%. The obtained dried 5'-disodium guanylate heptahydrate crystals weighed 261 g, and had a yield of 78.0% and a purity of 95.0%. In the specific case of the above crystal 5 (w/v)% aqueous solution, the transmittance (T)% was 95.0% and the pH was 7.0 to 8.5.
[62]
[63]
1 is a microscopic photograph of 5'-disodium guanylate heptahydrate crystals obtained according to Example 1. FIG. 1 , the crystals of 5'-disodium guanylate were columnar, and it was confirmed that the crystals obtained according to Example 1 were 5'-disodium guanylate heptahydrate.
[64]
[65]
Comparative Example 1
[66]
5'-Disodium guanylate 380 g/L solution, 1.3 L was added instead of 0.875 L, and the experiment was performed according to the same procedure as in the above example, except that the sodium chloride concentration in the mixed solution was 130.4 g/L. As a result, although the crystal seeds were added and observed for 6 hours, the transition of the amorphous solid to 5'-disodium guanylate heptahydrate was not observed. After the temperature of the mixed solution was cooled to 25° C. or less over two hours, the amorphous solid remained as it was, so it could not be separated by centrifugation using a basket separator.
[67]
[68]
Comparative Example 2
[69]
Using 0.3g of 5% NaOH, 0.875L of 380g/L aqueous solution of 5'-disodium guanylate was slowly added to 300g/L 1L aqueous solution of sodium chloride at a temperature of 40°C adjusted to pH 9. At a sodium chloride concentration of 160g/L, amorphous Amorphous crystals were transferred to plate-shaped tetragonal crystals. While maintaining the internal temperature of the mixed solution of the salt aqueous solution and the 5'-disodium guanylate aqueous solution at about 52°C, 1% by weight of crystal seeds was added to the mixed solution based on the weight of 5'-disodium guanylate, and the crystal transition was completed within 1 hour. , the transferred crystals were plate-shaped quaternary crystals rather than columnar-shaped quaternary crystals.
[70]
[71]
FIG. 2 is a microscopic photograph of plate-shaped 5'-disodium guanylate tetrahydrate crystals obtained according to Comparative Example 2. FIG.
[72]
[73]
Comparative Example 3: Crystal using an organic solvent
[74]
In 1.5L of 200g/L of 5'-disodium guanylate solution, 4.4g of Na 2 PO 4 was added and completely dissolved, followed by stirring at a temperature of 38° C. for 10 to 20 minutes at 120 rpm. After adding 0.2L of methanol per minute to this, 3.4ml of methanol was added, and 1% of 5'-disodium guanylate heptahydrate as a crystal seed was added based on the weight of 5'-disodium guanylate in the solution. After the system was completely equilibrated, 1L of methanol was repeatedly used. After crystallization at the same rate for a total of 5 hours at a rate of 3.4 ml per minute, it was dehydrated to obtain 295 g of columnar crystals.
[75]
As a result, the obtained crystals were naturally dried at 25°C for 12 hours to obtain dried 5'-disodium guanylate heptahydrate crystals. The dried crystals had a residual moisture content of 23.6 (w/v)%.
[76]
Table 1 shows the amount of methanol used in the methods described in Example 1 and Comparative Example 3, the purity of the 5'-disodium guanylate heptahydrate crystals produced thereby, and the methanol content remaining therein. In Table 1, the amount of methanol used is based on the yield of 100 g of 5'-disodium guanylate heptahydrate. In addition, the purity (%) of 5'-disodium guanylate heptahydrate was measured according to the method described in Example 1. The residual methanol content represents the methanol remaining in the 5 (w/v)% aqueous solution of the crystal.
[77]
[Table 1]
Methanol usage (g) 5'-disodium guanylate heptahydrate purity (%) Residual methanol content (ppm)
Comparative Example 3 270 95.06 850
Example 1 0 95.00 not detected
[78]
As shown in Table 1, the crystal of Example 1 was able to maintain a purity of 95% or more, which was similar to Comparative Example 3.
[79]
[80]
In Comparative Example 3, 270 g of methanol as an organic solvent should be used to obtain 100 g of 5'-disodium guanylate heptahydrate crystals, but in Example 1, no organic solvent was used.
[81]
FIG. 3 is a microscopic photograph of 5'-disodium guanylate heptahydrate crystals obtained by using methanol, which is a hydrophilic organic solvent, according to Comparative Example 3. FIG.
[82]
[83]
Evaluation Example 1. Effect of Salt Concentration in Mixed Solution on Crystal Formation
[84]
In this section, sodium chloride 400 g/L aqueous solution is used instead of sodium chloride 300 g/L aqueous solution, and the NaCl concentration in the mixed solution is 120 to 380 g/L by adding different amounts of 5'-disodium guanylate aqueous solution. The experiment was performed according to the same procedure as in Example 1.
[85]
As a result, amorphous solids or crystals formed in the mixed solution were observed through a microscope. The results are shown in Table 2.
[86]
[Table 2]
Sodium Chloride Concentration (g/L) solid substance form Transition time (minutes)
120 amorphous solid -
140 amorphous solid -
160 Determination of the number 7 of the columnar type 30
200 Determination of the number 7 of the columnar type 25
300 Determination of the number 7 of the columnar type 25
360 Determination of the number 7 of the columnar type 25
380 Columnar hexadecimal crystals or small crystals mixed with sodium chloride 25
[87]
As shown in Table 2, when the concentration of sodium chloride in the mixed solution was 160 g/L or more, the amorphous solid form of 5'-disodium guanylate was converted to heptahydrate. On the other hand, when the concentration of sodium chloride in the mixed solution exceeds 360 g/L, it was difficult to separate 5'-disodium guanylate from the crystal slurry because the crystal size was small and a crystal mixed with sodium chloride was obtained. The larger the crystal size, the easier it is to separate the 5'-disodium guanylate crystal from the crystal slurry. As a result, in consideration of the results of Section 2 below, it was confirmed that heptahydrate of 5'-disodium guanylate was formed at a salt concentration of 160 to 360 g/L in the mixed solution.
[88]
[89]
Evaluation Example 2. Solubility of 5'-guanylic acid in the mixed solution
[90]
When the 5'-guanylic acid aqueous solution was added to the sodium chloride aqueous solution with different sodium chloride concentrations at a temperature of 40 °C and 25 °C, the solubility of 5'-guanylic acid was confirmed.
[91]
[92]
Specifically, a saturated solution was prepared by sufficiently dissolving 5'-guanylic acid aqueous solution in each sodium chloride aqueous solution at 40°C and 25°C, respectively. As a result, a saturated solution containing sodium chloride at a concentration of 160 to 360 g/L was prepared. As shown in Tables 3 and 4, salt crystals were precipitated in a solution containing 400 g/L or more of sodium chloride in the mixed solution. Next, the supernatant obtained by centrifuging the saturated solution, that is, the concentration (g/L) of 5'-guanylic acid in the mixed solution was measured.
[93]
[94]
Tables 3 and 4 show the concentrations of 5'-disodium guanylate heptahydrate with respect to the aqueous sodium chloride solution at 40°C and 25°C, respectively.
[95]
[Table 3]
Sodium Chloride Concentration (g/L) 160 200 230 280 300 310 350 360 400 over 400
5'-guanylic acid concentration in the mixed solution (g/L) 86.5 62.7 57.1 50.1 49.9 49.5 48.9 49.8 49.6 Salt crystal precipitation 48.7 Salt crystal precipitation
[96]
[Table 4]
Sodium Chloride Concentration (g/L) 160 200 230 280 300 310 350 360 400 420
5'-guanylic acid concentration in the mixed solution (g/L) 40.1 26.4 22.2 19.2 18.1 18.2 18.2 18.2 18.3 Salt Crystal Precipitation 18.2 Salt Crystal Precipitation
[97]
As shown in Tables 3 and 4, 5'-disodium guanylate heptahydrate has a low solubility in each sodium chloride aqueous solution of 160 g/L to 360 g/L, for example, 160 g/L to 360 g/L. Confirmed. On the other hand, 5'-disodium guanylate heptahydrate was dissolved in an aqueous sodium chloride solution of less than 160 g/L without maintaining the columnar shape.
[98]
[99]
Evaluation Example 3. Effect of temperature of mixed solution on crystal formation
[100]
To 1 L of an aqueous sodium chloride solution having a concentration of 300 g/L adjusted to pH 9 using 0.3 g of 5% NaOH, 0.875 L of an aqueous solution of 380 g/L 5'-disodium guanylate was slowly added. In the mixed solution, the concentration of sodium chloride was 160 g/L, the concentration of 5'-disodium guanylate was 200 g/L, and after adjusting the internal temperature of the mixed solution as shown in Table 5 below, the crystal seeds were weighed with 5'-disodium guanylate. By adding 1 wt% compared to that, it was observed through a microscope whether the amorphous solid of 5'-sodium guanylate was transformed into heptahydrate crystals. Table 5 shows the crystals according to the temperature of the mixed solution.
[101]
[Table 5]
Temperature (℃) crystal form Transition time (min)
20 Determination of the number 7 of the columnar type 180
25 Determination of the number 7 of the columnar type 80
30 Determination of the number 7 of the columnar type 60
35 Determination of the number 7 of the columnar type 42
40 Determination of the number 7 of the columnar type 30
45 Determination of the number 7 of the columnar type 25
50 Plate-shaped 4 number crystal 30
[102]
As shown in Table 5, it was confirmed that the transition to the columnar heptahydrate crystal was confirmed even at 20°C, but it took some time for the transition, and it was confirmed that the amorphous solid rapidly transitioned to the heptahydrate from a temperature of 25°C or higher. On the other hand, at temperatures above 45° C., the amorphous solid transitioned to tetrahydrate.
[103]
[104]
Evaluation Example 4. Effect of the amount of added crystal seeds on crystal formation
[105]
To 1 L of an aqueous sodium chloride solution having a concentration of 300 g/L adjusted to pH 9 using 0.3 g of 5% NaOH, 0.875 L of an aqueous solution of 5'-guanylic acid having a concentration of 380 g/L was slowly added. The concentration of sodium chloride in the obtained mixed solution was 160 g/L, the concentration of 5'-guanylic acid was 200 g/L, and the temperature of the mixed solution was 40 °C.
[106]
[107]
After the amorphous solid was formed, crystal seeds were added as shown in Table 6 below, and the crystal transition rate was observed through a microscope. Table 6 shows the crystals according to the amount of crystal seeds added to the mixed solution.
[108]
[Table 6]
Crystal seed weight (based on 100 parts by weight of 5'-sodium guanylate) crystal form Transition time (min)
0.05 Determination of the number 7 of the columnar type 80
0.1 Determination of the number 7 of the columnar type 60
0.5 Determination of the number 7 of the columnar type 40
1.0 Determination of the number 7 of the columnar type 30
2.5 Determination of the number 7 of the columnar type 30
5.0 Determination of the number 7 of the columnar type 25
5.5 Determination of the number 7 of the columnar type 25
[109]
As shown in Table 6, as the weight of the added crystal seed increases, the time for transition of 5'-disodium guanylate from an amorphous solid to a columnar heptahydrate tends to be shortened, but it is included in excess of 5.0 parts by weight In this case, it was confirmed that the transition time was no longer reduced.
Claims
[Claim 1]
forming an amorphous solid in the mixed solution by mixing an aqueous salt solution and an aqueous 5'-guanylic acid solution; And adding crystal seeds to the mixed solution to form 5'-disodium guanylate heptahydrate crystals; including, wherein the step of adding the crystal seeds is performed while maintaining the temperature at 25 to 45 ° C., 5' - Method for preparing disodium guanylate heptahydrate crystals.
[Claim 2]
The method of claim 1, wherein the salt concentration in the mixed solution is 160 to 360 g/L.
[Claim 3]
The method according to claim 1, wherein the aqueous salt solution has a pH of 7 to 10.
[Claim 4]
The method according to claim 1, wherein the salt concentration of the aqueous salt solution is 200 to 400 g / L.
[Claim 5]
The method according to claim 1, wherein the 5'-guanylic acid concentration of the aqueous solution of 5'- guanylic acid is 50 to 400 g / L of the method.
[Claim 6]
The method according to claim 1, wherein the 5'-guanylic acid aqueous solution comprises one obtained by culturing microorganisms.
[Claim 7]
The method of claim 1 , wherein the crystal seeds comprise 5′-disodium guanylate heptahydrate crystals.
[Claim 8]
The method according to claim 1, wherein the amount of the crystal seed to be added is 0.1 to 5.5 parts by weight based on 100 parts by weight of the 5'-guanylate.
[Claim 9]
The method of claim 1 , further comprising cooling the solution containing the crystals formed after the step of forming the 5′-disodium guanylate heptahydrate crystals.
[Claim 10]
The method according to claim 9, wherein the cooling is carried out to 25 ℃ or less.
[Claim 11]
The method of claim 1 , wherein the salt comprises an alkali metal salt.
[Claim 12]
The method of claim 1 , wherein the salt comprises NaCl.