Separation and preparation method of D-chiro-inositol

Abstract

The invention discloses a separation and preparation method of D-chiro-inositol, and relates to the technical field of D-chiro-inositol production, a D-chiro-inositol conversion liquid is subjected to thallus removal, deproteinization, desalination and concentration, then ethanol is added for primary separation, ethanol is added again for crystallization after dealcoholization, D-chiro-inositol is purified, and the D-chiro-inositol is obtained. The ethanol is an inert solvent, more chiral inositol in the solution can be crystallized by adding the ethanol, the yield is increased, after the ethanol is added, the viscosity of a crystallization system is reduced, the flowability of the system is better, the crystal can grow more uniformly during crystallization, the crystal is more uniform, and the purity of the product is improved. And the quality of the D-chiro-inositol is improved.

Description

Technical Field

[0001] The invention relates to the technical field of D-chiro-inositol production, and in particular to a method for separating and preparing D-chiro-inositol. Background Art

[0002] D-Chiro-Inositol (DCI) is the most optically active of the nine isomers of inositol and the biologically active isomer of vitamin B8. It is found at relatively high levels in plants such as buckwheat seeds and soybeans, as well as in some insects, primarily as methylated or glycosylated derivatives. It is a biodegradable product of buckwheat sugar alcohol. It has insulin-sensitizing effects and promotes liver fat metabolism, significantly lowering blood sugar levels and having a significant therapeutic effect on diabetes. DCI also has benefits such as improving polycystic ovary syndrome (PCOS), providing antioxidant and anti-aging benefits, and scavenging free radicals, making it a valuable therapeutic option.

[0003] D-chiro-inositol can be extracted from plants such as buckwheat, but its content in these plants is low, resulting in poor resource utilization and high extraction costs. D-chiro-inositol can also be produced through organic synthesis, but due to the complex steps, byproducts are difficult to separate and toxic residues can remain, affecting product quality. Furthermore, large amounts of organic solvents are required, making it environmentally unfriendly. Furthermore, D-chiro-inositol can be produced by hydrolyzing D-pinitol or kasugamycin, but these raw materials are expensive, making them uneconomical.

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

[0005] The technical problem to be solved by the present invention is: in view of the deficiencies in the prior art, a method for separating and preparing D-chiro-inositol is provided, wherein the obtained D-chiro-inositol has high purity and quality.

[0006] In order to solve the above technical problems, the technical solution of the present invention is: A method for separating and preparing D-chiro-inositol comprises the following steps: A: After the D-chiro-inositol conversion solution is subjected to bacterial removal, protein removal, desalting, and concentration, a concentrated solution I with a solid content of 30-40% w / w is obtained; B: Add 0.5-1 times the volume of ethanol to the concentrated solution I, keep warm at 50-60°C for 1-2 hours, then cool to 25-30°C, add 0.5-1 times the volume of ethanol to the concentrated solution I again, stir for 5-10 hours, filter, and collect the filtrate I and filter cake I; C: Filtrate I is distilled to recover ethanol and the dealcoholized liquid is collected; D: The dealcoholized liquid is concentrated to a solid content of 40-60% w / w to obtain concentrated liquid II. Ethanol in an amount of 0.2-1.0 times the volume of concentrated liquid II is added at 50-60°C, then cooled to 25-30°C, filtered, and filter cake II and filtrate II are collected; E: Dissolve filter cake II in purified water. Add 0.3-1 times the volume of ethanol to the resulting solution at 50-60°C. Cool to 10-15°C for crystallization. Collect filter cake III and filtrate III by filtration. Dry filter cake III to obtain D-chiro-inositol.

[0007] Preferably, the D-chiro-inositol conversion liquid in step A is filtered using a ceramic membrane to remove bacteria, then filtered through an ultrafiltration membrane to remove protein, and then desalted through a cation exchange resin and an anion exchange resin respectively, and then concentrated through a nanofiltration membrane to a solid content of 12-15% w / w, and finally concentrated under vacuum <-0.09 MPa, 70-90° C. to obtain concentrated solution I.

[0008] Preferably, the D-chiro-inositol conversion solution is first filtered to remove large particles of impurities and then filtered using a ceramic membrane; The mesh size of the prefilter 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 membrane inlet pressure is controlled at 3-3.5 MPa; the feed flow rate of the cation exchange resin and the anion exchange resin is 1-2 BV / h, the cation exchange resin is regenerated with a 4-5 wt% hydrochloric acid solution before use, and the anion exchange resin is regenerated with a 4-5 wt% sodium hydroxide solution.

[0009] Preferably, the filter cake I is myo-inositol, which is recovered for reconversion.

[0010] Preferably, the filtrate I is a high-content chiro-inositol ethanol solution, with a chiro-inositol content of >80%.

[0011] Preferably, the dealcoholated solution in step D is concentrated to a solid content of 40-60% w / w under vacuum conditions of <-0.09 MPa and 70-90°C.

[0012] Preferably, the filtrate II is returned to step A for re-concentration.

[0013] Preferably, the amount of purified water added in step E is 0.5-2 times the weight of filter cake II, and the dissolution temperature is 50-80°C.

[0014] Preferably, the solution in step E is first decolorized by adding activated carbon and diatomaceous earth, and then ethanol is added for cooling and crystallization, wherein the amount of activated carbon added accounts for 1-3% of the volume of the solution, the amount of diatomaceous earth added accounts for 0.5-1% of the volume of the solution, and the decolorization time is 20-40 min.

[0015] Preferably, filtrate III is returned to filtrate I for further concentration.

[0016] Due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. Before the D-chiro-inositol conversion liquid enters the ceramic membrane, a pre-filter is used to remove large particle impurities. This can not only speed up the filtration speed, prevent contamination of the ceramic membrane, and extend the service life of the ceramic membrane, but also reduce the loss of D-chiro-inositol in the concentrated solution and increase the yield.

[0017] 2. The solubility of chiro-inositol in ethanol solution is greater than that of myo-inositol. At a temperature of 50-60°C, first add ethanol in an amount of 0.5-1 times the volume of the feed solution, keep warm for 1-2 hours, then cool to 25-30°C, add ethanol in an amount of 0.5-1 times the volume of the feed solution again, and stir for 5-10 hours. The two-step gradient addition of ethanol can promote the effective separation of impurities and target products, reduce the entrainment loss of the target product in filter cake I, and improve the yield of the product.

[0018] 3. The dealcoholated liquid is concentrated to a solid content of 40-60% w / w to obtain concentrated liquid II. Ethanol in an amount 0.2-1.0 times the volume of concentrated liquid II is added at 50-60°C, and then the temperature is lowered to 25-30°C. By controlling the concentration, temperature and amount of ethanol added, chiro-inositol is crystallized from the system, thereby increasing the content of chiro-inositol in the solid to more than 95%, thereby achieving the purpose of purification.

[0019] 4. Add ethanol to the solution to cool and crystallize. Ethanol is an inert solvent. Adding ethanol can make more chiro-inositol in the solution crystallize out, increase the yield, and after adding ethanol, the viscosity of the crystallization system becomes smaller, the system fluidity is better, and during crystallization, the crystals can grow more evenly, making the crystals more uniform and improving the quality of D-chiro-inositol.

[0020] 5. Through multi-stage purification treatments such as ceramic membrane removal of bacteria, ultrafiltration membrane removal of proteins, and anion and cation exchange resin desalination, various impurities in the conversion liquid can be deeply removed, laying a high-purity foundation for subsequent crystallization and purification. During the multiple crystallization processes, by precisely controlling the amount of ethanol added, temperature, and crystallization time, residual impurities can be gradually removed, and the final D-chiro-inositol obtained is of extremely high purity.

[0021] 6. Filter cake I is recovered and converted, filtrate II is recycled to step A for re-concentration, and filtrate III is recycled to filtrate I for reprocessing, forming a complete material circulation system that can minimize material loss in the production process and significantly improve the overall yield of D-chiro-inositol.

[0022] 7. In step E, filter cake II is dissolved and then crystallized again, and activated carbon and diatomaceous earth are introduced for decolorization treatment to further remove pigments and trace impurities, thereby improving the purity and appearance quality of the final product.

[0023] 8. The application of membrane separation technology improves the efficiency of impurity removal and concentration. The multiple crystallization process, through rational control of time and temperature, ensures both purification and production efficiency. Furthermore, material recycling reduces raw material waste, making the overall process suitable for large-scale industrial production and capable of stably and efficiently producing high-purity D-chiro-inositol. The separated myo-inositol is then reconverted to fully utilize the raw materials, improve the resource conversion rate of the entire process, and enhance the economic efficiency of production. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a liquid chromatogram of D-chiro-inositol in Example 1 of the present invention; Figure 2 is a liquid chromatogram of D-chiro-inositol in Example 2 of the present invention; Figure 3 is a liquid chromatogram of D-chiro-inositol in Example 3 of the present invention; Figure 4 This is a crystal image of D-chiro-inositol in Example 1 of the present invention observed under a 10x microscope. DETAILED DESCRIPTION

[0025] The present invention will be further described below with reference to the embodiments. Example 1

[0026] 1. Take 50 L of D-chiro-inositol conversion solution (the conversion solution is obtained by adding inositol dehydrogenase and 2-keto-inositol isomerase to myo-inositol with a substrate mass concentration of 10%, wherein D-chiro-inositol accounts for 15% w / w and myo-inositol accounts for 85% w / w in the conversion solution) and use a 5 μm pre-filter to remove large particulate impurities to obtain 50 L of pre-filtered solution; 2. The pre-filtered liquid of 50 nm was filtered through a ceramic membrane, and 53 L of the ceramic membrane clear liquid was collected.

[0027] 3. The ceramic membrane clear liquid was filtered through a 2500Da ultrafiltration membrane, and 58L of ultrafiltration clear liquid was collected; 4. The ultrafiltrate was first passed through a cation exchange resin at a feed rate of 1 BV / h, and then through an anion exchange resin at a feed rate of 1 BV / h. 68 L of desalted liquid was collected. In this embodiment, the cation exchange resin was SQD-61 and the anion exchange resin was SQD-936. The cation exchange resin was regenerated with a 4 wt % hydrochloric acid solution before use, and the anion exchange resin was regenerated with a 4 wt % sodium hydroxide solution. 5. The desalted liquid was concentrated through a 200Da nanofiltration membrane to a solid content of 12% w / w, and the membrane inlet pressure was controlled at 3MPa; 6. The nanofiltration concentrate was concentrated under vacuum <-0.09 MPa and a temperature of 70°C to a solid content of 30% w / w (17 L). Ethanol (0.5 times the volume of the feed liquid) was added at 50°C, and the temperature was kept at that temperature for 1 hour. The temperature was then lowered to 25°C, and 0.5 times the volume of ethanol was added again. The mixture was stirred for 5 hours and filtered. 32 L of filtrate I and 3500 g of filter cake I were collected. Filter cake I was myo-inositol, which could be recycled for reconversion. Filtrate I was a high-content chiral inositol ethanol solution with a chiral inositol content greater than 80%. 7. 17 L of ethanol was recovered from filtrate I by distillation, and 15 L of dealcoholized liquid was collected. At this point, the solid content of the dealcoholized liquid was low and needed to be concentrated again; 8. The dealcoholate was concentrated under vacuum <-0.09 MPa and a temperature of 70°C to a solid content of 40% w / w (3.8 L). 0.2 times the amount of ethanol was added to the concentrate at 50°C, then cooled to 25°C and filtered to collect 720 g of filter cake II and 3.6 L of filtrate II. Filter cake II contained crude D-chiro-inositol with a content greater than 95%. Filtrate II was added to step 6 and the extraction was repeated. 9. Dissolve filter cake II in purified water to obtain 0.96 L of solution, where the amount of purified water added is 0.5 times the weight of filter cake II, and the dissolution temperature is 50°C; 10. Add 1% by volume of activated carbon and 0.5% by volume of diatomaceous earth to the solution for decolorization for 20 minutes, filter, and collect 0.96 L of decolorized liquid. Adding diatomaceous earth can absorb impurities and help filtration, which makes filtration better. 11. Slowly add ethanol to the decolorant at 50°C (0.3 times the volume of the decolorant). Cool to 10°C for crystallization. Filter and collect 705 g of filter cake III and 0.7 L of filtrate III. Dry filter cake III to obtain 671 g of D-chiro-inositol with a yield of 89.5%, a purity of 99.5%, and a crystal size of 25-30 mesh. Apply filtrate III to filtrate I and concentrate. Example 2

[0028] 1. Take 50 L of D-chiro-inositol conversion solution (the conversion solution is obtained by adding inositol dehydrogenase and 2-keto-inositol isomerase to myo-inositol with a substrate mass concentration of 10%, wherein D-chiro-inositol accounts for 15% w / w and myo-inositol accounts for 85% w / w) and use an 8 μm pre-filter to remove large particulate impurities to obtain 50 L of pre-filtered solution; 2. The pre-filtered liquid was filtered through an 80nm ceramic membrane, and 54L of ceramic membrane clear liquid was collected, and the concentrated liquid was treated in an environmentally friendly manner.

[0029] 3. The ceramic membrane clear liquid was filtered through a 4000Da ultrafiltration membrane, and 60L of ultrafiltration clear liquid was collected; 4. The ultrafiltrate was first passed through a cation exchange resin at a feed rate of 1.5 BV / h, and then through an anion exchange resin at a feed rate of 1.5 BV / h. 68 L of desalted liquid was collected. The cation exchange resin was SQD-61 and the anion exchange resin was SQD-936. The cation exchange resin was regenerated with 4.5 wt% hydrochloric acid before use, and the anion exchange resin was regenerated with 4.5 wt% sodium hydroxide. 5. The desalted liquid was concentrated through a 220Da nanofiltration membrane to a solid content of 13% w / w, and the membrane inlet pressure was controlled at 3.2 MPa; 6. The nanofiltration concentrate was concentrated under vacuum <-0.09 MPa and a temperature of 80°C to a solid content of 35% w / w (14 L). Ethanol (0.8 times the volume of the feed liquid) was added at a temperature of 55°C, and the temperature was kept at that temperature for 1.5 h. The temperature was then lowered to 28°C, and ethanol (0.8 times the volume of the feed liquid) was added again. The mixture was stirred for 8 h and filtered. 33 L of filtrate I and 3650 g of filter cake I were collected. Filter cake I was myo-inositol, which could be recycled for reconversion. Filtrate I was a high-content chiral inositol ethanol solution with a chiral inositol content greater than 80%. 7. 22 L of ethanol was recovered from filtrate I by distillation, and 11 L of dealcoholized liquid was collected. At this point, the solid content of the dealcoholized liquid was low and needed to be concentrated again; 8. The dealcoholate was concentrated under vacuum <-0.09 MPa and a temperature of 80°C to a solid content of 50% w / w (2.7 L). 0.7 times the amount of ethanol was added to the concentrate at 55°C, then the temperature was lowered to 28°C and filtered to collect 750 g of filter cake II and 4 L of filtrate II. Filter cake II contained crude D-chiro-inositol with a content greater than 95%. Filtrate II was added to step 6 and the extraction was repeated. 9. Dissolve filter cake II in purified water to obtain 1.2 L of solution, where the amount of purified water added is 1 times the weight of filter cake II, and the dissolution temperature is 70°C; 10. Add 2% by volume of activated carbon and 0.8% by volume of diatomaceous earth to the solution for decolorization for 30 minutes, filter, and collect 1.2 L of decolorized liquid. Adding diatomaceous earth can absorb impurities and help filtration, which makes filtration better. 11. Slowly add ethanol to the decolorant at 55°C (0.7 times the volume of the decolorant). Cool to 12°C for crystallization. Filter and collect 710 g of filter cake III and 1.4 L of filtrate III. Dry filter cake III to obtain 680 g of D-chiro-inositol with a yield of 90.1%, a purity of 99.6%, and a crystal size of 25-30 mesh. Apply filtrate III to filtrate I and concentrate. Example 3

[0030] 1. Take 50 L of D-chiro-inositol conversion solution (the conversion solution is obtained by adding inositol dehydrogenase and 2-keto-inositol isomerase to myo-inositol with a substrate mass concentration of 10%, wherein D-chiro-inositol accounts for 15% w / w and myo-inositol accounts for 85% w / w in the conversion solution) and use a 10 μm pre-filter to remove large particulate impurities to obtain 50 L of pre-filtered solution; 2. The pre-filtered liquid was filtered through a 100nm ceramic membrane, and 55L of the ceramic membrane clear liquid was collected, and the concentrated liquid was treated in an environmentally friendly manner.

[0031] 3. The ceramic membrane clear liquid was filtered through a 5000Da ultrafiltration membrane, and 60L of ultrafiltration clear liquid was collected; 4. The ultrafiltration clear fluid was first passed through a cation exchange resin at a feed rate of 2 BV / h, and then passed through an anion exchange resin at a feed rate of 2 BV / h. 68 L of desalted liquid was collected. The cation exchange resin used was SQD-61, and the anion exchange resin was SQD-936. The cation exchange resin was regenerated with 5 wt% hydrochloric acid before use, and the anion exchange resin was regenerated with 5 wt% sodium hydroxide. 5. The desalted liquid was concentrated through a 250Da nanofiltration membrane to a solid content of 15% w / w, and the membrane inlet pressure was controlled at 3.5MPa; 6. The nanofiltration concentrate was concentrated under vacuum <-0.09 MPa and a temperature of 90°C to a solid content of 40% w / w (12 L). At a temperature of 60°C, 1 times the volume of ethanol was added to the feed solution, the temperature was kept at 60°C for 2 hours, the temperature was then lowered to 30°C, and 1 times the volume of ethanol was added again. The mixture was stirred for 10 hours and filtered. 34 L of filtrate I and 3800 g of filter cake I were collected. The filter cake I was myo-inositol, which could be recycled for reconversion. The filtrate I was a high-content chiral inositol ethanol solution with a chiral inositol content greater than 80%. 7. 24 L of ethanol was recovered from filtrate I by distillation, and 10 L of dealcoholized liquid was collected. At this point, the solid content of the dealcoholized liquid was low and needed to be concentrated again; 8. The dealcoholate was concentrated under vacuum <-0.09 MPa and a temperature of 90°C to a solid content of 60% w / w 2L. 1.0 times the amount of ethanol in the concentrate was added at 60°C, and then the temperature was lowered to 30°C and filtered to collect 780 g of filter cake II and 3.3 L of filtrate II. Filter cake II contained crude D-chiro-inositol with a content greater than 95%. Filtrate II was added to step 6 and the extraction was repeated. 9. Dissolve filter cake II in purified water to obtain 2.1 L of solution, where the amount of purified water added is twice the weight of filter cake II, and the dissolution temperature is 80°C; 10. Add 3% by volume of activated carbon and 1% by volume of diatomaceous earth to the solution for decolorization for 40 minutes, filter, and collect 2.1 L of decolorized liquid. Adding diatomaceous earth can absorb impurities and help filtration, which makes filtration better. 11. Slowly add ethanol to the decolorant at 60°C, with the amount of ethanol added being 1 times the volume of the decolorant. Cool to 15°C for crystallization, collect 720 g of filter cake III and 3.6 L of filtrate III by filtration. Dry filter cake III to obtain 685 g of D-chiro-inositol, with a yield of 91.3%, a purity of 99.6%, and a crystal particle size of 25-30 mesh. Apply filtrate III to filtrate I and concentrate.

[0032] It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope limited by the appended claims of the application.

Claims

1. A method for separating and preparing D-chiro-inositol, characterized in that The following steps are involved: A: After the D-chiro-inositol conversion solution is subjected to bacterial removal, protein removal, desalting, and concentration, a concentrated solution I with a solid content of 30-40% w / w is obtained; B: Add 0.5-1 times the volume of ethanol to the concentrated solution I, keep warm at 50-60°C for 1-2 hours, then cool to 25-30°C, add 0.5-1 times the volume of ethanol to the concentrated solution I again, stir for 5-10 hours, filter, and collect the filtrate I and filter cake I; C: Filtrate I is distilled to recover ethanol and the dealcoholized liquid is collected; D: The dealcoholized liquid is concentrated to a solid content of 40-60% w / w to obtain concentrated liquid II. Ethanol in an amount of 0.2-1.0 times the volume of concentrated liquid II is added at 50-60°C, then cooled to 25-30°C, filtered, and filter cake II and filtrate II are collected; E: Dissolve filter cake II in purified water. Add 0.3-1 times the volume of ethanol to the resulting solution at 50-60°C. Cool to 10-15°C for crystallization. Collect filter cake III and filtrate III by filtration. Dry filter cake III to obtain D-chiro-inositol.

2. a method for separating and preparing D-chiro-inositol as claimed in claim 1, characterized in that: In step A, the D-chiro-inositol conversion solution is filtered using a ceramic membrane to remove bacterial cells, then filtered through an ultrafiltration membrane to remove protein, and then desalted through a cation exchange resin and an anion exchange resin respectively, and then concentrated through a nanofiltration membrane to a solid content of 12-15% w / w, and finally concentrated under vacuum conditions of <-0.09 MPa and 70-90° C. to obtain concentrated solution I.

3. a method for separating and preparing D-chiro-inositol as claimed in claim 2, characterized in that: The D-chiro-inositol conversion solution was first filtered through a pre-filter to remove large particles of impurities, and then filtered through a ceramic membrane; The mesh size of the prefilter 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 membrane inlet pressure is controlled at 3-3.5 MPa; the feed flow rate of the cation exchange resin and the anion exchange resin is 1-2 BV / h, the cation exchange resin is regenerated with a 4-5 wt% hydrochloric acid solution before use, and the anion exchange resin is regenerated with a 4-5 wt% sodium hydroxide solution.

4. a method for separating and preparing D-chiro-inositol as claimed in claim 1, characterized in that: Filter cake I is myo-inositol, which is recovered for re-conversion.

5. a method for separating and preparing D-chiro-inositol as claimed in claim 1, characterized in that: Filtrate I is a high-content chiro-inositol ethanol solution with a chiro-inositol content of >80%.

6. A method for separating and preparing D-chiro-inositol as claimed in claim 1, characterized in that: In step D, the dealcoholate solution is concentrated under vacuum conditions of <-0.09 MPa and 70-90° C. to a solid content of 40-60% w / w.

7. A method for separating and preparing D-chiro-inositol as claimed in claim 1, characterized in that: Filtrate II was returned to step A for re-concentration.

8. A method for separating and preparing D-chiro-inositol as claimed 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°C.

9. A method for separating and preparing D-chiro-inositol as claimed in claim 1, characterized in that: The solution in step E is first decolorized by adding activated carbon and diatomaceous earth, and then ethanol is added for cooling and crystallization, wherein the amount of activated carbon added accounts for 1-3% of the volume of the solution, the amount of diatomaceous earth added accounts for 0.5-1% of the volume of the solution, and the decolorization time is 20-40 minutes.

10. A method for separating and preparing D-chiro-inositol according to claim 1, characterized in that: Filtrate III was returned to filtrate I and concentrated.

Images