A method for the isolation and preparation of D-chiral inositol

Abstract

This invention discloses a method for separating and preparing D-chiral inositol, relating to the field of D-chiral inositol production technology. The D-chiral inositol conversion solution is subjected to sterilization, protein removal, desalting, and concentration. Then, ethanol is added for preliminary separation. After de-alcoholization, ethanol is added again for crystallization to purify the D-chiral inositol. Finally, ethanol is added to the solution for cooling and crystallization. Ethanol is an inert solvent; adding ethanol allows more chiral inositol to crystallize from the solution, increasing the yield. Adding ethanol also reduces the viscosity of the crystallization system, improving its fluidity and allowing for more uniform crystal growth, thus improving the quality of D-chiral inositol.

Description

Technical Field

[0001] This invention relates to the field of D-chiral inositol production technology, and specifically to a method for the separation and preparation of D-chiral inositol. Background Technology

[0002] D-Chiro Inositol (DCI) is one of the nine isomers of inositol that exhibits optical activity. It is also the bioactive isomer of vitamin B8. It exists in relatively high levels in buckwheat seeds, soybeans, and some insects, primarily in the form of methylated or glycosylated derivatives, and is a biodegradation product of buckwheat glycosides. It possesses insulin-sensitizing properties and promotes hepatic fat metabolism, significantly lowering blood glucose levels and showing a marked therapeutic effect on diabetes. Furthermore, DCI also has effects such as improving polycystic ovary syndrome (PCOS), anti-oxidation, anti-aging, and free radical scavenging, making it of considerable practical value.

[0003] D-Chiral inositol can be extracted from plants such as buckwheat; however, the content of D-chiral inositol in these plants is low, resulting in poor resource utilization and high extraction costs. D-chiral inositol can also be prepared through organic synthesis, but this method is cumbersome, byproducts are difficult to separate, and toxic residues may remain, affecting product quality. Furthermore, it requires large amounts of organic solvents, making it environmentally unfriendly. Additionally, D-chiral inositol can be produced by hydrolyzing D-pineol or kasugamycin; however, the raw materials D-pineol or kasugamycin are expensive, making it uneconomical.

[0004] In recent years, the bioconversion synthesis of D-chiral inositol has become a new development trend. Currently, research mainly focuses on two aspects: modifying microorganisms to convert muscle inositol into chiral inositol and improving the conversion rate. However, the conversion rate is low, and the resulting D-chiral inositol and muscle inositol are difficult to separate, resulting in low purity of D-chiral inositol and making it difficult to achieve industrial production. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a method for separating and preparing D-chiral inositol, which has high purity and quality, in order to address the shortcomings of the existing technology.

[0006] To solve the above-mentioned technical problems, the technical solution of the present invention is as follows:

[0007] A method for isolating and preparing D-chiral inositol, comprising the following steps:

[0008] A: After sterilization, protein removal, desalting, and concentration, D-chiral inositol conversion solution yields concentrated solution I with a solid content of 30-40% w / w.

[0009] B: Add 0.5-1 times the volume of ethanol to concentrate I, keep it at 50-60℃ for 1-2 hours, then cool it down to 25-30℃, add 0.5-1 times the volume of ethanol to concentrate I again, stir for 5-10 hours, filter, and collect filtrate I and filter cake I.

[0010] C: Filtrate I was distilled to recover ethanol, and the dealcoholized liquid was collected;

[0011] D: Concentrate the dealcoholized liquid to a solid content of 40-60% w / w to obtain concentrate II. Add 0.2-1.0 times the volume of ethanol to concentrate II at 50-60℃, then cool to 25-30℃, filter, and collect filter cake II and filtrate II.

[0012] E: Dissolve filter cake II in purified water. Add 0.3-1 times the volume of ethanol to the resulting solution at 50-60℃, cool and crystallize to 10-15℃, filter and collect filter cake III and filtrate III. Dry filter cake III to obtain D-chiral inositol.

[0013] Preferably, in step A, the D-chiral inositol conversion solution is filtered through a ceramic membrane to remove bacterial cells, then filtered through an ultrafiltration membrane to remove proteins, then desalted through cation exchange resin and anion exchange resin respectively, then concentrated through a nanofiltration membrane to a solid content of 12-15% w / w, and finally concentrated under vacuum < -0.09 MPa and 70-90°C to obtain concentrated solution I.

[0014] Preferably, the D-chiral inositol conversion solution is first filtered to remove large particulate impurities, and then filtered using a ceramic membrane.

[0015] The pre-filter has a mesh size of 5-10 μm; the ceramic membrane has a mesh size of 50-100 nm; the ultrafiltration membrane has a molecular weight cutoff of 2500-5000 Da; the nanofiltration membrane has a molecular weight cutoff of 200-250 Da, and the inlet pressure is controlled at 3-3.5 MPa; the feed flow rate for both cation exchange resin and anion exchange resin is 1-2 BV / h; the cation exchange resin is regenerated with 4-5 wt% hydrochloric acid solution before use, and the anion exchange resin is regenerated with 4-5 wt% sodium hydroxide solution.

[0016] Preferably, filter cake I is muscle inositol, which is recovered and reconstituted.

[0017] Preferably, filtrate I is a high-content chiral inositol ethanol solution with a chiral inositol content >80%.

[0018] Preferably, in step D, the dealcoholized liquid is concentrated to a solid content of 40-60% w / w under vacuum < -0.09 MPa and 70-90°C.

[0019] Preferably, filtrate II is returned to step A for reconcentration.

[0020] Preferably, in step E, the amount of purified water added is 0.5-2 times the weight of filter cake II, and the dissolution temperature is 50-80℃.

[0021] Preferably, in step E, activated carbon and diatomaceous earth are first added to the solution for decolorization, and then ethanol is added for cooling and crystallization. The amount of activated carbon added accounts for 1-3% of the volume of the solution, and the amount of diatomaceous earth added accounts for 0.5-1% of the volume of the solution. The decolorization time is 20-40 minutes.

[0022] Preferably, filtrate III is recycled back to filtrate I for further concentration.

[0023] Due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0024] 1. Before the D-chiral inositol conversion solution enters the ceramic membrane, a pre-filter is used to remove large particulate impurities. This not only speeds up the filtration process, prevents contamination of the ceramic membrane, and extends its service life, but also reduces the loss of D-chiral inositol in the concentrate and increases the yield.

[0025] 2. Chiral inositol has a higher solubility in ethanol solution than muscle inositol. At a temperature of 50-60℃, first add 0.5-1 times the volume of the feed solution of ethanol, keep warm for 1-2 hours, then cool down to 25-30℃, and add another 0.5-1 times the volume of ethanol, stirring for 5-10 hours. By adding ethanol in two gradients, the impurities can be effectively separated from the target product, the entrainment loss of the target product in filter cake I can be reduced, and the product yield can be improved.

[0026] 3. Concentrate the dealcoholized solution to a solid content of 40-60% w / w to obtain concentrate II. Add 0.2-1.0 times the volume of ethanol to concentrate II at 50-60℃, and then cool to 25-30℃. By controlling the concentration of the solution, temperature and the amount of ethanol added, chiral inositol can be crystallized from the system, increasing the content of chiral inositol in the solid to more than 95%, thus achieving the purpose of purification.

[0027] 4. Add ethanol to the solution for cooling and crystallization. Ethanol is an inert solvent. Adding ethanol can make more chiral inositol crystallize out of the solution, increasing the yield. After adding ethanol, the viscosity of the crystallization system will decrease, the system will have better fluidity, and the crystals can grow more uniformly during crystallization, making the crystals more homogeneous and improving the quality of D-chiral inositol.

[0028] 5. Through multi-stage purification processes such as ceramic membrane sterilization, ultrafiltration membrane protein removal, and anion and cation exchange resin desalination, various impurities in the conversion solution can be deeply removed, laying a high-purity foundation for subsequent crystallization and purification. During multiple crystallization processes, by precisely controlling the amount of ethanol added, temperature, and crystallization time, residual impurities can be gradually eliminated, and the final D-chiral inositol obtained has extremely high purity.

[0029] 6. The process of recycling and converting filter cake I, returning filtrate II to step A for re-concentration, and returning filtrate III to filtrate I for further treatment forms a complete material recycling system, which can minimize material loss in the production process and significantly improve the total yield of D-chiral inositol.

[0030] 7. In step E, filter cake II is dissolved and recrystallized, and activated carbon and diatomaceous earth are introduced for decolorization treatment, which can further remove pigments and trace impurities, making the purity and appearance quality of the final product better.

[0031] 8. The application of membrane separation technology improves the efficiency of impurity removal and concentration. Multiple crystallization processes, through reasonable control of time and temperature, ensure both purification effectiveness and production efficiency. Furthermore, material recycling reduces raw material waste. The overall process is suitable for large-scale industrial production, stably and efficiently producing high-purity D-chiral inositol. The separated muscle inositol is then further converted, achieving full utilization of the raw materials, improving the resource conversion rate of the entire process, and increasing the economics of production. Attached Figure Description

[0032] Figure 1 This is the liquid chromatogram of D-chiral inositol in Example 1 of the present invention;

[0033] Figure 2 This is the liquid chromatogram of D-chiral inositol in Example 2 of the present invention;

[0034] Figure 3 This is the liquid chromatogram of D-chiral inositol in Example 3 of the present invention;

[0035] Figure 4 This is a crystal image of D-chiral inositol observed under a 10x microscope in Example 1 of the present invention. Detailed Implementation

[0036] The present invention will be further illustrated below with reference to the embodiments. Example 1

[0037] 1. Take 50L of D-chiral inositol conversion solution (the conversion solution is obtained by converting 10% muscle inositol with the addition of inositol dehydrogenase and 2-ketoinositol isomerase, wherein the proportion of D-chiral inositol in the conversion solution is 15% w / w and the proportion of muscle inositol is 85% w / w) and use a 5μm pre-filter to remove large particulate impurities to obtain 50L of pre-filtered solution;

[0038] 2. The pre-filtered liquid (50 nm) was filtered through a ceramic membrane, and 53 L of the clear liquid was collected.

[0039] 3. The supernatant obtained from the ceramic membrane was filtered through a 2500 Da ultrafiltration membrane, and 58 L of supernatant was collected.

[0040] 4. The ultrafiltrate is first passed through a cation exchange resin at a feed flow rate of 1 BV / h, and then through an anion exchange resin at a feed flow rate of 1 BV / h. 68 L of desalination solution is collected. In this embodiment, SQD-61 is used as the cation exchange resin and SQD-936 is used as the anion exchange resin. The cation exchange resin is regenerated with a 4 wt% hydrochloric acid solution before use, and the anion exchange resin is regenerated with a 4 wt% sodium hydroxide solution.

[0041] 5. The desalination solution is concentrated through a 200 Da nanofiltration membrane to a solid content of 12% w / w, with the inlet pressure controlled at 3 MPa;

[0042] 6. The nanofiltration concentrate was concentrated under vacuum < -0.09 MPa and temperature of 70°C until the solid content was 30% w / w 17 L. Then, at 50°C, 0.5 times the volume of ethanol was added to the concentrate and kept at this temperature for 1 h. The temperature was then lowered to 25°C, and another 0.5 times the volume of ethanol was added. The mixture was stirred for 5 h, filtered, and 32 L of filtrate I and 3500 g of filter cake I were collected. Filter cake I is composed of muscle inositol, which can be recovered and reconstituted. Filtrate I is a high-content chiral inositol ethanol solution with a chiral inositol content greater than 80%.

[0043] 7. 17L of ethanol was recovered by distillation of filtrate I, and 15L of dealcoholized liquid was collected. At this time, the solid content of the dealcoholized liquid was low and it needed to be concentrated again.

[0044] 8. The dealcoholized solution was concentrated under vacuum < -0.09 MPa and temperature of 70°C until the solid content was 40% w / w (3.8 L). Ethanol of 0.2 times the concentration was added at 50°C, and then the temperature was lowered to 25°C. The solution was filtered, and 720 g of filter cake II and 3.6 L of filtrate II were collected. Filter cake II was crude D-chiral inositol with a content greater than 95%. Filtrate II was added to step 6 and the extraction was repeated.

[0045] 9. Dissolve filter cake II in purified water to obtain 0.96 L of solution, wherein the amount of purified water added is 0.5 times the weight of filter cake II, and the dissolution temperature is 50℃;

[0046] 10. Add 1% (v / v) activated carbon and 0.5% (v / v) diatomaceous earth to the solution for decolorization for 20 min, filter, and collect 0.96 L of decolorized solution. Adding diatomaceous earth can adsorb impurities and also has the effect of filtration, making filtration better.

[0047] 11. Ethanol is slowly added to the decolorizing solution at 50℃, with the amount of ethanol added being 0.3 times the volume of the decolorizing solution. The solution is cooled to crystallize at 10℃, and the filter cake III (705g) and filtrate III (0.7L) are collected. Filter cake III is dried to obtain D-chiral inositol (671g), with a yield of 89.5%, a purity of 99.5%, and a crystal particle size of 25-30 mesh. Filtrate III is reused in filtrate I for further concentration. Example 2

[0048] 1. Take 50L of D-chiral inositol conversion solution (the conversion solution is obtained by adding inositol dehydrogenase and 2-ketoinositol isomerase to 10% muscle inositol substrate, wherein the proportion of D-chiral inositol in the conversion solution is 15% w / w and the proportion of muscle inositol is 85% w / w) and use an 8μm pre-filter to remove large particulate impurities to obtain 50L of pre-filtered solution;

[0049] 2. The pre-filtered liquid is filtered through an 80nm ceramic membrane, and 54L of clear liquid is collected. The concentrated liquid is then treated in an environmentally friendly manner.

[0050] 3. The supernatant obtained through the ceramic membrane was filtered through a 4000 Da ultrafiltration membrane, and 60 L of supernatant was collected.

[0051] 4. The ultrafiltrate is first passed through a cation exchange resin at a feed flow rate of 1.5 BV / h, and then through an anion exchange resin at a feed flow rate of 1.5 BV / h. 68 L of desalination solution is collected. SQD-61 is selected as the cation exchange resin and SQD-936 is selected as the anion exchange resin. The cation exchange resin is regenerated with 4.5 wt% hydrochloric acid before use, and the anion exchange resin is regenerated with 4.5 wt% sodium hydroxide.

[0052] 5. The desalination solution is concentrated using a 220Da nanofiltration membrane to a solid content of 13% w / w, with the inlet pressure controlled at 3.2 MPa;

[0053] 6. The nanofiltration concentrate was concentrated under vacuum < -0.09 MPa and temperature 80℃ until the solid content was 35% w / w 14L. At 55℃, 0.8 times the volume of the feed liquid was added to ethanol and kept at this temperature for 1.5h. Then, the temperature was lowered to 28℃, and another 0.8 times the volume of ethanol was added. The mixture was stirred for 8h, filtered, and 33L of filtrate I and 3650g of filter cake I were collected. Filter cake I is muscle inositol, which can be recovered and reconstituted. Filtrate I is a high-content chiral inositol ethanol solution with a chiral inositol content greater than 80%.

[0054] 7. Filtrate I was distilled to recover 22L of ethanol and 11L of dealcoholized liquid was collected. At this point, the dealcoholized liquid had a low solid content and needed to be concentrated again.

[0055] 8. The dealcoholized solution was concentrated under vacuum < -0.09 MPa and temperature of 80°C until the solid content was 50% w / w 2.7 L. Then, 0.7 times the amount of ethanol was added to the concentrate at temperature of 55°C, and then the temperature was lowered to 28°C. The solution was filtered, and 750 g of filter cake II and 4 L of filtrate II were collected. Filter cake II was crude D-chiral inositol with a content greater than 95%. Filtrate II was added to step 6 and the extraction was repeated.

[0056] 9. Dissolve filter cake II in purified water to obtain 1.2L of solution, wherein the amount of purified water added is 1 times the weight of filter cake II, and the dissolution temperature is 70℃;

[0057] 10. Add 2% (v / v) activated carbon and 0.8% (v / v) diatomaceous earth to the solution for decolorization for 30 min, filter, and collect 1.2 L of decolorized solution. Adding diatomaceous earth can adsorb impurities and also has the effect of filtration, making filtration better.

[0058] 11. Ethanol is slowly added to the decolorizing solution at 55℃, with the amount of ethanol added being 0.7 times the volume of the decolorizing solution. The solution is cooled to crystallize at 12℃, and 710g of filter cake III and 1.4L of filtrate III are collected by filtration. Filter cake III is dried to obtain 680g of D-chiral inositol, with a yield of 90.1%, a purity of 99.6%, and a crystal particle size of 25-30 mesh. Filtrate III is reused in filtrate I for further concentration. Example 3

[0059] 1. Take 50L of D-chiral inositol conversion solution (the conversion solution is obtained by adding inositol dehydrogenase and 2-ketoinositol isomerase to 10% muscle inositol substrate, wherein the proportion of D-chiral inositol in the conversion solution is 15% w / w and the proportion of muscle inositol is 85% w / w) and use a 10μm pre-filter to remove large particulate impurities to obtain 50L of pre-filtered solution;

[0060] 2. The pre-filtered liquid is filtered through a 100nm ceramic membrane, and 55L of clear liquid is collected. The concentrated liquid is then treated in an environmentally friendly manner.

[0061] 3. The supernatant obtained through the ceramic membrane is filtered through a 5000 Da ultrafiltration membrane, and 60 L of supernatant is collected.

[0062] 4. The ultrafiltrate is first passed through a cation exchange resin at a feed flow rate of 2 BV / h, and then through an anion exchange resin at a feed flow rate of 2 BV / h. 68 L of desalination solution is collected. SQD-61 is selected as the cation exchange resin and SQD-936 is selected as the anion exchange resin. The cation exchange resin is regenerated with 5 wt% hydrochloric acid before use, and the anion exchange resin is regenerated with 5 wt% sodium hydroxide.

[0063] 5. The desalination solution is concentrated using a 250Da nanofiltration membrane to a solid content of 15% w / w, with the inlet pressure controlled at 3.5 MPa;

[0064] 6. The nanofiltration concentrate was concentrated under vacuum < -0.09 MPa and temperature of 90°C until the solid content was 40% w / w 12 L. At 60°C, ethanol with a volume equal to that of the feed solution was added and kept at this temperature for 2 h. Then, the temperature was lowered to 30°C, and ethanol with a volume equal to that of the feed solution was added again. The mixture was stirred for 10 h, filtered, and 34 L of filtrate I and 3800 g of filter cake I were collected. Filter cake I is muscle inositol, which can be recovered and reconstituted. Filtrate I is a high-content chiral inositol ethanol solution with a chiral inositol content greater than 80%.

[0065] 7. Filtrate I was distilled to recover 24L of ethanol and 10L of dealcoholized liquid was collected. At this point, the dealcoholized liquid had a low solid content and needed to be concentrated again.

[0066] 8. The dealcoholized solution was concentrated under vacuum < -0.09 MPa and temperature of 90°C until the solid content was 60% w / w 2L. Ethanol of 1.0 times the concentration was added at 60°C, and then the temperature was lowered to 30°C. The solution was filtered, and 780g of filter cake II and 3.3L of filtrate II were collected. Filter cake II was crude D-chiral inositol with a content greater than 95%. Filtrate II was added to step 6 and the extraction was repeated.

[0067] 9. Dissolve filter cake II in purified water to obtain 2.1L of solution, wherein the amount of purified water added is twice the weight of filter cake II, and the dissolution temperature is 80℃;

[0068] 10. Add 3% (v / v) activated carbon and 1% (v / v) diatomaceous earth to the solution for decolorization for 40 min, filter, and collect 2.1 L of decolorized solution. Adding diatomaceous earth can adsorb impurities and also has the effect of filtration, making filtration better.

[0069] 11. Ethanol is slowly added to the decolorizing solution at 60℃, with the amount of ethanol added being 1 times the volume of the decolorizing solution. The solution is cooled to crystallize at 15℃, and 720g of filter cake III and 3.6L of filtrate III are collected by filtration. Filter cake III is dried to obtain 685g of D-chiral inositol, with a yield of 91.3%, a purity of 99.6%, and a crystal particle size of 25-30 mesh. Filtrate III is reused in filtrate I for further concentration.

[0070] It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

Claims

1. A method for the isolation and preparation of D-chiral inositol, characterized in that... Includes the following steps: A: The D-chiral inositol conversion solution first uses a pre-filter to remove large particulate impurities, then uses a ceramic membrane filter to remove bacterial cells, followed by ultrafiltration to remove proteins, then desalted by cation exchange resin and anion exchange resin respectively, and then concentrated by nanofiltration to a solid content of 12-15% w / w. Finally, it is concentrated under vacuum < -0.09 MPa and 70-90℃ to obtain concentrate I with a solid content of 30-40% w / w. The mesh size of the pre-filter is 5-10 μm; the mesh size of the ceramic membrane is 50-100 nm; the molecular weight cutoff of the ultrafiltration membrane is 2500-5000 Da; the molecular weight cutoff of the nanofiltration membrane is 200-250 Da, and the inlet pressure is controlled at 3-3.5 MPa; the feed flow rate of both cation exchange resin and anion exchange resin is 1-2 BV / h; the cation exchange resin is regenerated with 4-5 wt% hydrochloric acid solution before use, and the anion exchange resin is regenerated with 4-5 wt% sodium hydroxide solution. B: Add 0.5-1 times the volume of ethanol to concentrate I, keep it at 50-60℃ for 1-2 hours, then cool it down to 25-30℃, add 0.5-1 times the volume of ethanol to concentrate I again, stir for 5-10 hours, filter, and collect filtrate I and filter cake I. C: Filtrate I was distilled to recover ethanol, and the dealcoholized liquid was collected; D: Concentrate the dealcoholized liquid to a solid content of 40-60% w / w to obtain concentrate II. Add 0.2-1.0 times the volume of ethanol to concentrate II at 50-60℃, then cool to 25-30℃, filter, and collect filter cake II and filtrate II. E: Dissolve filter cake II in purified water. Add 0.3-1 times the volume of ethanol to the resulting solution at 50-60℃, cool and crystallize to 10-15℃, filter and collect filter cake III and filtrate III. Dry filter cake III to obtain D-chiral inositol.

2. The method for separating and preparing D-chiral inositol as described in claim 1, characterized in that: Filter cake I contains muscle inositol, which is recovered and reconstituted.

3. The method for separating and preparing D-chiral inositol as described in claim 1, characterized in that: Filtrate I is a high-content chiral inositol ethanol solution with a chiral inositol content >80%.

4. The method for separating and preparing D-chiral inositol as described in claim 1, characterized in that: In step D, the dealcoholized solution is concentrated to a solid content of 40-60% w / w under vacuum < -0.09 MPa and 70-90°C.

5. The method for separating and preparing D-chiral inositol as described in claim 1, characterized in that: Filtrate II is returned to step A for reconcentration.

6. The method for separating and preparing D-chiral inositol as described in claim 1, characterized in that: In step E, the amount of purified water added is 0.5-2 times the weight of filter cake II, and the dissolution temperature is 50-80℃.

7. The method for separating and preparing D-chiral inositol as described in claim 1, characterized in that: In step E, activated carbon and diatomaceous earth are first added to the solution for decolorization, and then ethanol is added for cooling and crystallization. The amount of activated carbon added accounts for 1-3% of the volume of the solution, and the amount of diatomaceous earth added accounts for 0.5-1% of the volume of the solution. The decolorization time is 20-40 minutes.

8. The method for separating and preparing D-chiral inositol as described in claim 1, characterized in that: Filtrate III is returned to Filtrate I for further concentration.

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