Method for preparing high-purity shikimic acid from fermentation liquor

Abstract

The invention provides a method for preparing high-purity shikimic acid from fermentation liquor, which comprises the following steps: firstly, carrying out alkalization treatment on the fermentation liquor under a heating condition to effectively remove dehydrogenated shikimic acid, and then, reducing the concentration of monovalent inorganic ions through nanofiltration concentration to effectively improve the resin treatment capacity. The use amount of ion exchange resin and the generation amount of regenerated wastewater are reduced; impurities in the solution are removed through ion exchange resin, so that the product purity is further improved; and finally, by controlling parameters in the crystallization process and washing crystals with deionized water at 4 DEG C, the specific rotation of the product is further improved. After the multiple technical means are adopted for cooperative treatment, on the premise that no organic solvent is used, direct crystallization of shikimic acid in the aqueous solution is achieved, and the high-purity shikimic acid product with the purity larger than or equal to 99.85%, the content larger than or equal to 100.1% and the specific rotation smaller than or equal to-182.3 degrees is obtained.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of medicine preparation, and particularly relates to a method for preparing high-purity shikimic acid from fermentation liquor. BACKGROUND

[0002] Shikimic acid (3,4,5-trihydroxy-1-cyclohexene-1-carboxylic acid, abbreviated as SA) is a natural organic acid with a molecular formula of C7H 10 O5, a relative molecular weight of 174.15 Da, and an ionization constant of 3.85. It mainly exists in the mature dried fruits of coniferous plants and magnolia plants. In addition, shikimic acid has optical activity, and natural shikimic acid is all left-handed.

[0003] From the biological function, shikimic acid is a substance with biological activity, and it is a key intermediate for synthesizing alkaloids, aromatic amino acids, and phenolic compounds in plant and microbial metabolism. Modern pharmacological studies have shown that shikimic acid has functions such as antibacterial, antitumor, anticoagulant, and anti-inflammatory. In addition, shikimic acid is also an important starting material for chemical synthesis, such as the synthesis of the anti-influenza virus drug oseltamivir phosphate (which has preventive and therapeutic effects on influenza B, H9N2, H5N1, etc.).

[0004] However, there are certain difficulties in the separation and purification of shikimic acid in the prior art: on the one hand, shikimic acid has high water solubility and usually needs to be highly concentrated to crystallize; on the other hand, the fermentation liquor of shikimic acid contains dehydroshikimic acid, gallic acid, and protocatechuic acid (the above three by-products are similar in structure to shikimic acid and are difficult to separate from shikimic acid), substrates such as glucose, pigments, proteins, and other impurities. Even after the impurities are removed by centrifugal filtration and other steps, a small amount of impurities will still remain, affecting the quality of the product.

[0005] In addition, the traditional separation and purification method of shikimic acid generally relies on organic solvents such as methanol, ethanol, and ethyl acetate to improve separation efficiency or promote crystallization. The use of a large amount of these organic solvents not only increases the cost of the production process, but also causes a series of environmental and safety problems: first, organic solvents are volatile, which not only pollutes the atmosphere, but also seriously threatens the health of operating personnel. Second, the use of organic solvents produces a large amount of wastewater containing solvents, which is complex in composition and difficult to treat, seriously increasing the burden of pharmaceutical production enterprises; if not properly treated and discharged, it will cause water pollution, which is contrary to the current concept of green and environmentally friendly production. Finally, some separation processes that rely on organic solvents also have problems such as long reaction period and complicated operation steps, which restrict the efficiency of pharmaceutical production and make it difficult to meet the needs of large-scale and efficient industrial production.

[0006] In summary, how to effectively improve the purity of the prepared shikimic acid without using organic solvents is a problem that needs to be solved by those skilled in the art. SUMMARY

[0007] The present application aims to provide a method for preparing high-purity shikimic acid from fermentation broth. Specifically comprising: first, alkali treatment of the fermentation broth under heating conditions, effectively removing dehydroshikimic acid, initially reducing the impurity content of the product and improving the purity of the product; then, through nanofiltration concentration to reduce the concentration of monovalent inorganic ions, effectively increasing the resin treatment capacity, reducing the ion exchange resin dosage and the amount of regeneration wastewater; then removing the impurity content in the solution through ion exchange resin, further improving the purity of the product; finally, by controlling the parameters in the crystallization process and using 4℃ ion-free water to wash the crystals, further improving the specific rotation of the product. The present application uses the above-mentioned multiple technical means for synergistic treatment, realizes the direct crystallization of shikimic acid in aqueous solution without using any organic solvent, and obtains high-purity shikimic acid product with purity ≥99.85%, content ≥100.1%, and specific rotation ≦-182.3°. The method provided by the present application effectively solves the problems of low product content and high waste liquid treatment cost in the existing fermentation broth extraction of shikimic acid, and has a broad application prospect.

[0008] To achieve the above-mentioned purpose, the present application provides a method for preparing high-purity shikimic acid from fermentation broth, comprising the following steps:

[0009] 1) heating the shikimic acid fermentation broth to 50~55℃, adding an alkaline reagent to adjust the system pH to 9.0~10.0, and then reacting after heat preservation, and then using ceramic membrane solid-liquid separation to obtain filtrate A with dehydroshikimic acid content ≤0.1g / L;

[0010] 2) concentrating the obtained filtrate A with nanofiltration membrane to obtain concentrated liquid B;

[0011] 3) adding an acid reagent to adjust the system pH to 2.5~3.0 in the obtained concentrated liquid B, and adding activated carbon for decolorization treatment to obtain liquid C;

[0012] 4) treating the obtained liquid C with nanofiltration membrane to obtain filtrate D;

[0013] 5) treating the obtained filtrate D with ion exchange resin to obtain ion exchange liquid E;

[0014] 6) treating the obtained ion exchange liquid E with MVR concentration to obtain concentrated liquid F;

[0015] 7) cooling and crystallizing the obtained concentrated liquid F, and then filtering, washing with 4℃ ion-free water, and drying the obtained wet powder to obtain high-purity shikimic acid.

[0016] In a preferred embodiment, in step 1), the alkaline reagent is a sodium hydroxide solution; preferably, the mass concentration of the alkaline reagent is 10-20%.

[0017] In a preferred embodiment, in step 1), the heat preservation reaction time is 1-2 hours.

[0018] In a preferred embodiment, in step 1), the pore size of the ceramic membrane is 20-50 nm.

[0019] In a preferred embodiment, in step 2), the molecular weight cut-off of the nanofiltration membrane is 150-200 Da; preferably, the temperature of the filtrate in the nanofiltration concentration step is 10-40°C.

[0020] In a preferred embodiment, in step 2), the volume of the concentrated solution B obtained is 30-50% of the volume of the filtrate A.

[0021] In a preferred embodiment, in step 3), the acidic reagent is a sulfuric acid solution; preferably, the mass concentration of the acidic reagent is 30-50%.

[0022] In a preferred embodiment, in step 3), in the decolorization treatment step, the volume ratio of the activated carbon to the liquid is (1-2) g:100 mL; the decolorization temperature is 50-60°C, and the decolorization time is 40-60 minutes.

[0023] In a preferred embodiment, in step 4), the structure of the nanofiltration membrane in the nanofiltration membrane treatment is a tubular membrane, and the material of the nanofiltration membrane is polyether sulfone; in the nanofiltration process, the temperature of the fermentation broth is controlled to be below 50°C, and the pH is 2.5-3.0; preferably, the temperature of the fermentation broth is controlled to be 10-40°C.

[0024] In a preferred embodiment, in step 5), in the ion exchange resin treatment, the cation exchange resin used is 732, and the anion exchange resin is D301; the temperature of the ion exchange resin treatment is room temperature, and the column flow rate is 0.5-1.0 BV / h.

[0025] In a preferred embodiment, in step 5), in the ion exchange resin treatment, the pH of the effluent of the cation exchange resin is controlled to be 1.4-1.7.

[0026] In a preferred embodiment, in step 5), in the ion exchange resin treatment, the conductivity of the effluent of the anion exchange resin is controlled to be below 2000 μs / cm.

[0027] In a preferred embodiment, in step 5), the amount of the cationic resin and the anionic resin is both 2 L, and the ratio of the resin to the feed liquid is 1: (20-25).

[0028] In a preferred embodiment, in step 6), the MVR concentration treatment specifically comprises the following steps: first, filtering the ion exchange liquid E with a filter membrane with a pore size of 0.45 μm, and then concentrating under reduced pressure to a specific gravity of 1.20-1.25 g / ml; preferably, the concentration temperature under reduced pressure is 65-75 ℃, and the vacuum degree of the concentration under reduced pressure is -0.095 to -0.01 MPa.

[0029] In a preferred embodiment, in step 7), the cooling crystallization method is to cool at a gradient of 3-6 ℃ per hour.

[0030] In a preferred embodiment, in step 7), the crystallization temperature is 4-10 ℃, and the holding crystallization time is 8-10 hours.

[0031] In a preferred embodiment, in step 7), the ion-free aqueous solution washing is performed 2-4 times.

[0032] In a preferred embodiment, in step 7), the drying can be performed by using a conventional method known to those skilled in the art, such as a drying temperature of 55-60 ℃, a vacuum degree of ≤-0.095 MPa, and a drying time of 2-6 hours.

[0033] In a preferred embodiment, in step 7), the prepared shikimic acid has a purity of ≥99.85%, a content of ≥100.1%, and an optical rotation of ≤-182.3°.

[0034] Compared with the prior art, the technical scheme of the present application has the following advantages:

[0035] 1. Without using any organic solvent, the method of the present application first performs alkalization treatment on the fermentation liquid under heating conditions, effectively removes dehydroshikimic acid, preliminarily reduces the impurity content of the product, and improves the product purity; then reduces the concentration of monovalent inorganic ions through nanofiltration concentration, effectively improves the resin treatment capacity, reduces the ion exchange resin consumption and the amount of generated regeneration wastewater; further removes the impurity content in the solution through ion exchange resin, further improves the product purity; finally, by controlling the parameters in the crystallization process and using 4 ℃ ion-free water to wash the crystals, the optical rotation of the product is further improved. After the above-mentioned multiple technical means are used for synergistic treatment, high-purity shikimic acid product can be obtained.

[0036] 2、The application does not use any organic solvent, is friendly to the environment, and after synergistic treatment of alkalization, ceramic membrane filtration, nanofiltration concentration, ion exchange and MVR concentration, the obtained concentrated solution can be directly crystallized in an aqueous solution under specific crystallization parameter conditions, and after the crystal is washed with 4 DEG C ion-free aqueous solution, the specific rotation of the product is further improved, and the purification effect is remarkable.

[0037] 3、The process is developed after comprehensive consideration of safety in production, green environmental protection, treatment cost and product quality, and is a separation and purification process for extracting high-purity shikimic acid from fermentation liquor, the prepared shikimic acid has a purity of 99.85%, a content of 100.1% and a specific rotation of-182.3 DEG. BRIEF DESCRIPTION OF DRAWINGS

[0038] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed in the specific embodiments or the prior art description will be briefly introduced as follows. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0039] Figure 1 HPLC spectrum of shikimic acid and quinic acid impurities in fermentation liquor used for examples and comparative examples;

[0040] Figure 2 HPLC spectrum of shikimic acid purity in the product obtained in Example 1;

[0041] Fig. 3(a) is an HPLC spectrum of shikimic acid standard, and Fig. 3(b) is an HPLC spectrum of shikimic acid in the product obtained in Comparative Example 1;

[0042] Fig. 4(a) is an HPLC spectrum of shikimic acid standard, and Fig. 4(b) is an HPLC spectrum of shikimic acid in the product obtained in Comparative Example 2;

[0043] Figure 5 HPLC spectrum of shikimic acid purity in the product obtained by using organic reagent washing in Comparative Example 3. DETAILED DESCRIPTION

[0044] In order to make those skilled in the art better understand the present application, the present application will be further described in detail in combination with the drawings and specific embodiments, but it should be understood that the protection scope of the present application is not limited by the specific embodiments. Based on the examples in the present application, all other examples obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0045] If not specifically indicated, the technical means used in the present application are the conventional means familiar to those skilled in the art, and various raw materials, reagents, instruments and equipment used in the present application can be purchased from the market or prepared by the existing methods. The reagents used in the present application are analytical pure unless otherwise specified. In the present application, the normal temperature is 25±3°C.

[0046] In the examples and comparative examples of the present application, the content and purity of shikimic acid in the shikimic acid product are measured by HPLC method. The determination conditions are as follows:

[0047] Column: Welch AQ-C18 4.6 mm*250 mm, 3 μm

[0048] Mobile phase: acetonitrile: 0.1wt% phosphoric acid aqueous solution = 2:98 (v / v);

[0049] Elution mode: isocratic elution;

[0050] Column temperature: 35°C;

[0051] Flow rate of mobile phase: 1 mL / min;

[0052] Injection volume: 10 μL;

[0053] Detection wavelength: 210 nm.

[0054] Example 1

[0055] A separation and purification method for extracting high-purity shikimic acid from fermentation broth, the steps are as follows:

[0056] 1) Take 50 L of fermentation broth, heat the fermentation broth to 55°C, adjust the pH to 9.4 using a 15% sodium hydroxide solution, and incubate for 1 h, then filter using a ceramic membrane with a pore size of 50 nm to obtain 90 L of filtrate.

[0057] 2) Concentrate the ceramic membrane filtrate by nanofiltration, and when the flux decreases significantly, wash with water, control the temperature of the feed liquid to 40°C, and use a nanofiltration membrane with a molecular weight cutoff of 200 Da to obtain 42 L of concentrated liquid.

[0058] 3) Adjust the pH of the solution to 2.5 using a 30% sulfuric acid solution, heat to 55°C, and add 1% (w / v) activated carbon for decolorization treatment, with a decolorization time of 60 min, filter out the carbon to obtain 40 L of decolorized liquid.

[0059] 4) Control the decolorized liquid at 30°C, pass through nanofiltration, and when the flow rate decreases to about half, add dialysis water, control the shikimic acid content in the retentate to be below 10 g / L, and obtain 48 L of feed liquid.

[0060] 5) The filtrate is treated with resin at room temperature, the cation exchange resin is 732, and the anion exchange resin is D301, the flow rate through the column is controlled at 1.0 BV / h, the pH of the cation exchange resin effluent is controlled at 1.5, and the conductivity of the anion exchange resin effluent is controlled at 1600 μs / cm. The amount of cation resin and anion resin used is both 2 L, and the amount of resin to feed solution is 1:23.

[0061] 6) The diafiltration effluent is first filtered through a water system membrane with a pore size of 0.45 μm, and then concentrated under reduced pressure to a specific gravity of 1.2 g / ml, the reduced pressure concentration conditions including a temperature of 70°C and a vacuum degree of -0.098 MPa.

[0062] 7) In the concentrated solution, the temperature is controlled at 55°C, and stirring is performed for 3 hours, then the temperature is decreased to 4°C at a rate of 5°C per hour, and the solution is incubated for crystallization for 8 hours.

[0063] 8) The crystallized solution is filtered, and when there is no obvious water effluent, the wet powder is washed with 4°C deionized water for 3 times, and then dried, the drying conditions including a temperature of 60°C, a vacuum degree of -0.095 MPa, and a drying time of 30 hours.

[0064] The purity of the obtained product is 99.87%, the shikimic acid content is 100.3%, and the specific rotation is -182.3°.

[0065] Example 2

[0066] 1) 50 L of fermentation broth is taken, the fermentation broth is heated to 50°C, and the pH is adjusted to 9.6 using a 10% sodium hydroxide solution, and incubated for 1.5 hours, then filtered through a ceramic membrane with a pore size of 50 nm, and 88 L of filtrate is obtained.

[0067] 2) The ceramic membrane filtrate is concentrated by nanofiltration, and when the flux decreases significantly, the material is washed with water, the temperature of the material is controlled at 35°C, the molecular weight cut-off of the nanofiltration membrane is 200 Da, and 40 L of concentrated solution is obtained.

[0068] 3) A 35% sulfuric acid solution is used to adjust the pH of the solution to 2.8, and 1.5% (w / v) activated carbon is added to the solution at 57°C for decolorization treatment, the decolorization time is 60 minutes, the activated carbon is removed by filtration, and 39 L of decolorized solution is obtained.

[0069] 4) The decolorized solution is controlled at 30°C, and then subjected to nanofiltration, and when the flow rate decreases to about half, the dialysis water is added, the shikimic acid content of the cut-off solution is controlled to be less than 10 g / L, and 45 L of material solution is obtained.

[0070] 5) The filtrate is treated with resin at room temperature, the cation exchange resin is 732, the anion exchange resin is D301, the flow rate through the column is controlled at 1.0 BV / h, the pH of the cation exchange resin effluent is controlled at 1.6, the conductivity of the anion exchange resin effluent is controlled at 1550 μs / cm, the amount of cation resin and anion resin used is 2 L, and the amount of resin to feed is 1:22.

[0071] 6) The ion exchange effluent is first filtered with a water-based membrane with a pore size of 0.45 μm, and then concentrated under reduced pressure to a specific gravity of 1.22 g / ml, the reduced pressure concentration conditions including a temperature of 70°C and a vacuum degree of -0.097 MPa.

[0072] 7) In the concentrated solution, the temperature is controlled at 60°C, stirring for 3 hours, and then gradiently cooled to 5°C at a rate of 5°C per hour, and incubated for crystallization for 10 h.

[0073] 8) The crystallized solution is filtered, washed with 4°C deionized water for 3 times when there is no obvious water outflow, and the wet powder is dried, the drying conditions being a temperature of 58°C, a vacuum degree of -0.096 MPa, and a drying time of 30 h.

[0074] The purity of the obtained product is 99.89%, the shikimic acid content is 100.2%, and the specific rotation is -182.5°

[0075] Example 3

[0076] 1) 50 L of fermentation broth is taken, the fermentation broth is heated to 55°C, a 20% sodium hydroxide solution is used to adjust the pH to 9.8, incubated for 2 h, and then filtered with a ceramic membrane with a pore size of 50 nm to obtain 92 L of filtrate.

[0077] 2) The ceramic membrane filtrate is concentrated by nanofiltration, and when the flux decreases significantly, the material liquid is washed with water, the material liquid temperature is controlled at 35°C, the nanofiltration membrane cut-off molecular weight is 200 Da, and 46 L of concentrated solution is obtained.

[0078] 3) A 40% sulfuric acid solution is used to adjust the solution pH to 2.6, heated to 60°C, 2% (w / v) activated carbon is added for decolorization treatment, the decolorization time is 60 min, the activated carbon is removed by filtration, and 44 L of decolorized solution is obtained.

[0079] 4) The decolorized solution is controlled at 30°C, nanofiltration is performed, the flow rate is reduced to about half, and dialysis water is added, the shikimic acid content of the cut-off liquid is controlled to be less than 10 g / L, and 50 L of material liquid is obtained.

[0080] 5) The filtrate was treated with resin at room temperature, the cation exchange resin was 732, the anion exchange resin was D301, the flow rate through the column was controlled at 1.0 BV / h, the pH of the cation exchange resin effluent was controlled at 1.5, the conductivity of the anion exchange resin effluent was controlled at 1575 μs / cm, the amount of cation resin and anion resin used was 2 L, and the amount of the ion exchange effluent was 44 L, the ratio of resin to feed was 1:22.

[0081] 6) The ion exchange effluent was first filtered through a water-based membrane with a pore size of 0.45 μm, and then concentrated under reduced pressure to a specific gravity of 1.24 g / ml, the reduced pressure concentration conditions included a temperature of 70°C and a vacuum degree of -0.096 MPa.

[0082] 7) In the concentrated solution, the temperature was controlled at 60°C, stirring for 3 hours, and then the temperature was gradually reduced to 6°C at a rate of 5°C per hour, and the crystallization was maintained for 9 hours.

[0083] 8) The crystallization solution was filtered, washed with 4°C deionized water for 3 times when there was no obvious water outflow, and the wet powder was dried, the drying conditions were: temperature 60°C, vacuum degree -0.097 MPa, and drying time 30 h.

[0084] The purity of the obtained product was 99.85%, the shikimic acid content was 100.1%, and the specific rotation was -183.4°

[0085] Comparative Example 1

[0086] 1) 50 L of fermentation broth was heated to 60°C, and filtered through a ceramic membrane with a pore size of 50 nm, during the filtration process, in order to fully elute the adsorbed shikimic acid of the trapped impurities, an appropriate amount of deionized water was added to the system, and finally 87 L of filtrate was collected.

[0087] 2) The pH of the system was adjusted to 9.6 using a 20% sodium hydroxide solution, and after 2 h of incubation, the system was filtered.

[0088] 3) The pH of the system was adjusted to 2.7 using a 40% sulfuric acid solution, and the system was heated to 60°C, 1% (w / v) activated carbon was added for decolorization treatment, the decolorization time was 60 min, the activated carbon was removed by filtration, and 85 L of decolorized solution was obtained.

[0089] 4) The filtrate was treated with resin at room temperature, the cation exchange resin was 732, the anion exchange resin was D301, the flow rate through the column was controlled at 1.0 BV / h, the pH of the cation exchange resin effluent was controlled at 1.4, the conductivity of the anion exchange resin effluent was controlled at 1600 μs / cm, the amount of cation resin and anion resin used was 2 L, and the amount of the ion exchange effluent was 10 L, the ratio of resin to feed was 1:5.

[0090] 5) The diafiltration liquid is first filtered through a water-based membrane with a pore size of 0.45 μm, and then concentrated under reduced pressure to a specific gravity of 1.2 g / ml. The reduced pressure concentration conditions include a temperature of 70°C and a vacuum degree of -0.097 MPa.

[0091] 6) In the concentrated liquid, the temperature is controlled at 60°C, and stirring is performed for 3 hours, and then the temperature is gradiently decreased to 4°C at a rate of 5°C per hour, and the temperature is maintained for crystallization for 9 hours.

[0092] 7) The crystallized liquid is subjected to suction filtration, and when there is no obvious water outflow, the wet powder is washed 3 times with 4°C ion-free water, and the wet powder is dried. The drying conditions are a temperature of 60°C, a vacuum degree of -0.098 MPa, and a drying time of 30 hours.

[0093] The purity of the obtained product is 92.5%, the shikimic acid content is 94.1%, and the specific rotation is -177°.

[0094] Comparative Example 2

[0095] 1) 50 L of the fermentation liquid is heated to 55°C, and filtered through a ceramic membrane with a pore size of 50 nm. During the filtration process, in order to sufficiently elute the shikimic acid adsorbed by the intercepted impurities, an appropriate amount of deionized water is supplemented to the system, and finally 87 L of filtrate is collected.

[0096] 2) The ceramic membrane filtrate is concentrated by nanofiltration, and when the flux significantly decreases, the water is backwashed. The temperature of the feed liquid is controlled at 40°C, and the nanofiltration membrane has a molecular weight cut-off of 200 Da. 43 L of concentrated liquid is obtained.

[0097] 3) A 30% sulfuric acid solution is used to adjust the pH of the solution to 2.5, and 1% (w / v) activated carbon is added to the solution heated to 55°C for decolorization treatment. The decolorization time is 60 minutes, and the activated carbon is removed by filtration. 41 L of decolorized liquid is obtained.

[0098] 4) The decolorized liquid is controlled at 30°C, and is subjected to nanofiltration. When the flow rate decreases to about half, dialysis water is added. The shikimic acid content of the retentate is controlled to be less than 10 g / L. 49 L of feed liquid is obtained.

[0099] 5) The filtrate is treated with resin at room temperature. The cation exchange resin is 732, and the anion exchange resin is D301. The flow rate through the column is controlled to be 1.0 BV / h. The pH of the effluent of the cation exchange resin is controlled to be 1.5. The conductivity of the effluent of the anion exchange resin is controlled to be 1600 μs / cm. The amount of the cation exchange resin and the anion exchange resin used is both 2 L. The amount ratio of the resin to the feed liquid is 1:21. 42 L of diafiltration liquid is obtained.

[0100] 5) The diafiltration liquid is first filtered through a water-based membrane with a pore size of 0.45 μm, and then concentrated under reduced pressure to a specific gravity of 1.2 g / ml. The reduced pressure concentration conditions include a temperature of 70°C and a vacuum degree of -0.098 MPa.

[0101] 6) The temperature of the concentrated solution was controlled at 55°C, and stirring was performed for 3 hours, and then the temperature was decreased to 4°C at a gradient of 5°C per hour, and the solution was kept at 4°C for 8 hours for crystallization.

[0102] 7) The crystallized solution was filtered, and when no water flowed out, the wet powder was washed with 4°C deionized water for 3 times, and the wet powder was dried under the following conditions: temperature 60°C, vacuum degree -0.095 MPa, and drying time 30 hours.

[0103] The purity of the obtained product was 98%, the shikimic acid content was 98.1%, and the specific rotation was -173°.

[0104] Comparative Example 3

[0105] 1) 50 L of the fermentation liquor was heated to 55°C, and after keeping the temperature for 2 hours, the fermentation liquor was filtered through a ceramic membrane with a pore size of 50 nm. During the filtration process, in order to sufficiently elute the shikimic acid adsorbed by the intercepted impurities, an appropriate amount of deionized water was added to the system, and finally 90 L of filtrate was collected.

[0106] 2) The ceramic membrane filtrate was concentrated by nanofiltration, and when the flux decreased significantly, the system was washed with water. The temperature of the material liquid was controlled at 35°C, and the molecular weight cut-off of the nanofiltration membrane was 200 Da. 47 L of concentrated solution was obtained.

[0107] 3) A 40% sulfuric acid solution was used to adjust the pH of the solution to 2.6, and the solution was heated to 60°C. 2% (w / v) activated carbon was added for decolorization treatment, and the decolorization time was 60 minutes. The activated carbon was removed by filtration, and 45 L of decolorized solution was obtained.

[0108] 4) The decolorized solution was controlled at 30°C, and was subjected to nanofiltration. When the flux decreased to about half, the system was washed with dialysis water. The shikimic acid content of the intercepted liquid was controlled to be less than 10 g / L, and 51 L of material liquid was obtained.

[0109] 5) The filtrate was treated with resin at room temperature. The cation exchange resin was 732, and the anion exchange resin was D301. The flow rate through the column was controlled at 1.0 BV / h. The pH of the effluent of the cation exchange resin was controlled at 1.5. The conductivity of the effluent of the anion exchange resin was controlled at 1600 μs / cm. The amount of the cation exchange resin and the anion exchange resin used was both 2 L. The amount ratio of the resin to the material liquid was 1:23, and 46 L of ion exchange liquid was obtained.

[0110] 6) The ion exchange liquid was first subjected to precision filtration through a water-based membrane with a pore size of 0.45 μm, and then was concentrated under reduced pressure to a specific gravity of 1.24 g / ml. The concentration conditions under reduced pressure included a temperature of 70°C and a vacuum degree of -0.096 MPa.

[0111] 7) In the concentrated solution, the temperature was controlled at 60°C, and stirring was performed for 3 hours, and then the temperature was decreased to 6°C at a gradient of 5°C per hour, and the solution was kept at 6°C for 9 hours for crystallization.

[0112] 8) The crystallization solution was filtered, and the wet powder was washed with 4°C ethanol for 3 times, and then dried at 60°C, under a vacuum of -0.098 MPa for 30 hours.

[0113] The purity of the obtained product was 99.83%, the shikimic acid content was 99.1%, and the specific rotation was -176°.

[0114] The foregoing description of specific exemplary embodiments of the application is intended to illustrate and exemplify the application and is not intended to limit the application to the precise forms disclosed. It will be apparent to those skilled in the art that many changes and modifications can be made to the application as described above, while still falling within the scope of the present application. These examples are chosen and described to explain the principles of the application and its practical application to enable one skilled in the art to best use the application and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the scope of the application be defined by the claims and their equivalents.

Claims

1. A method for preparing high-purity shikimic acid from fermentation broth, characterized in that, Includes the following steps: 1) Heat the shikimic acid fermentation broth to 50~55℃, add alkaline reagent to adjust the pH of the system to 9.0~10.0, keep the reaction at the temperature, and then separate the solid and liquid with a ceramic membrane to obtain filtrate A with a dehydroshikimic acid content ≤0.1g / L; 2) The obtained filtrate A is concentrated using a nanofiltration membrane to obtain concentrated solution B; 3) Add an acidic reagent to the obtained concentrated solution B to adjust the pH of the system to 2.5~3.0, add activated carbon for decolorization treatment, and obtain solution C; 4) The obtained liquid C is subjected to nanofiltration membrane treatment to obtain filtrate D; 5) The obtained filtrate D is treated with ion exchange resin to obtain ion exchange solution E; 6) The obtained ion exchange solution E is concentrated by MVR to obtain concentrated solution F; 7) Cool the obtained concentrated solution F to crystallize it. Filter the resulting crystallized solution, wash it with deionized water at 4°C, and dry the resulting wet powder to obtain high-purity shikimic acid.

2. The method for preparing high-purity shikimic acid from fermentation broth as described in claim 1, characterized in that, In step 1), the alkaline reagent is sodium hydroxide solution; the heat preservation reaction time is 1-2 hours; and the pore size of the ceramic membrane is 20-50 nm.

3. The method for preparing high-purity shikimic acid from fermentation broth as described in claim 1, characterized in that, In step 2), the nanofiltration membrane has a molecular weight cutoff of 150~200 Da; the volume of the resulting concentrated liquid B is 30~50% of the volume of the filtrate A.

4. The method for preparing high-purity shikimic acid from fermentation broth as described in claim 1, characterized in that, In step 3), the volume ratio of activated carbon to liquid in the decolorization process is (1~2)g:100mL; the decolorization temperature is 50~60℃ and the decolorization time is 40~60 minutes.

5. The method for preparing high-purity shikimic acid from fermentation broth as described in claim 1, characterized in that, In step 4), the nanofiltration membrane structure in the nanofiltration membrane treatment is a tubular membrane, and the nanofiltration membrane material is polyethersulfone; during the nanofiltration process, the temperature of the fermentation broth is controlled below 50°C, and the pH is 2.5~3.

0.

6. The method for preparing high-purity shikimic acid from fermentation broth as described in claim 1, characterized in that, In step 5), the cation exchange resin used in the ion exchange resin treatment is 732, and the anion exchange resin is D301; the temperature of the ion exchange resin treatment is room temperature, and the column flow rate is 0.5~1.0 BV / h.

7. The method for preparing high-purity shikimic acid from fermentation broth as described in claim 6, characterized in that, In step 5), during the ion exchange resin treatment, the pH of the cation exchange resin effluent is controlled at 1.4~1.7; and the conductivity of the anion exchange resin effluent is controlled below 2000 μs / cm.

8. The method for preparing high-purity shikimic acid from fermentation broth as described in claim 1, characterized in that, In step 6), the MVR concentration process specifically includes the following steps: first, the ion exchange liquid E is filtered through a filter membrane with a pore size of 0.45 μm, and then concentrated under reduced pressure to a specific gravity of 1.20~1.25 g / ml.

9. The method for preparing high-purity shikimic acid from fermentation broth as described in claim 1, characterized in that, In step 7), the cooling crystallization method is as follows: the temperature is gradually reduced at a rate of 3~6℃ per hour; the crystallization temperature is 4~10℃, and the holding time for crystallization is 8~10 hours.

10. The method for preparing high-purity shikimic acid from fermentation broth according to any one of claims 1-9, characterized in that, In step 7), the shikimic acid prepared has a purity of ≥99.85%, a content of ≥100.1%, and a specific rotation of ≦-182.3°.

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