Method for extracting D-ribose from D-ribose crystallization mother liquor

Abstract

The invention relates to the technical field of biochemical engineering, in particular to a method for extracting D-ribose from D-ribose crystallization mother liquor. According to the method, the crystallization mother liquor is directly treated by adopting the nanofiltration membrane, so that a large amount of pigments and the like in the crystallization mother liquor are removed; the method comprises the following steps: extracting ethanol from a crystallization mother solution, treating the treated crystallization mother solution by adopting a molecular sieve membrane, removing water in the crystallization mother solution while refluxing the ethanol, concentrating the crystallization mother solution, correspondingly increasing the ratio of ethanol and D-ribose in a concentrated solution, returning the concentrated solution to a crystallization tank, introducing a purified and concentrated fermentation solution into the crystallization tank, and crystallizing the D-ribose in the crystallization tank. Adding a proper amount of ethanol into the crystallizing tank according to the volume fraction of the ethanol in the crystallizing tank, and then cooling and crystallizing, thereby realizing the recovery of the D-ribose in the D-ribose crystallization mother liquor. The method is simple in technological process, the steps of evaporation and concentration and the like in a traditional process are avoided, meanwhile, ethanol is recycled under the condition that ethanol is not separated, more energy is saved, and the production cost of an enterprise is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of biochemical engineering, and in particular to a method for extracting D-ribose from D-ribose crystallization mother liquor. Background Art

[0002] D-ribose is a functional pentose and an important component of RNA, certain coenzymes and vitamins. It has very important physiological effects and has been widely used in food additives and drug production. The physiological effects of D-ribose have become a research hotspot in the field of nutrition and health care in recent years, and its clinical application has gradually increased. With the increase in domestic and foreign market demand, the production method of D-ribose has also evolved; microbial fermentation is currently the most economical, efficient and least environmentally polluting method for producing D-ribose, and has replaced chemical synthesis as the main method for industrial production of D-ribose.

[0003] The microbial fermentation method is a method of obtaining D-ribose fermentation liquid by fermenting glucose as raw material with a transketolase-deficient strain; the obtained fermentation liquid can be purified, concentrated and crystallized to obtain the D-ribose product. Due to the crystallization process, a large amount of crystallization mother liquor will be produced, and the crystallization mother liquor still contains a large amount of D-ribose, about 10wt%. This part of D-ribose cannot be further crystallized, so it will significantly reduce the yield of the product and is not conducive to reducing the production cost. Further processing the crystallization mother liquor to achieve the recovery of the D-ribose therein is an effective way to increase the product yield. However, due to the addition of ethanol during the crystallization process, it makes it difficult to recycle the crystallization mother liquor. There are existing methods for utilizing the crystallization mother liquor, such as the method recorded in the Chinese invention patent: "A method and device for extracting D-ribose from D-ribose crystallization mother liquor". In the process, ethanol is first separated from the crystallization mother liquor by evaporation, and the ethanol is prepared into anhydrous ethanol, and then the crystallization mother liquor from which ethanol is removed is diluted, purified, concentrated, and crystallized, thereby realizing the extraction of D-ribose from the crystallization mother liquor. This process realizes the recovery of D-ribose in the D-ribose crystallization mother liquor, but the process is complicated, energy-intensive, increases the cost of the product, and is not convenient for application in actual production.

[0004] Therefore, a method for recovering D-ribose from D-ribose crystallization mother liquor, which has a simpler process flow and can more effectively control production costs during the production process, is a technical problem that needs to be solved. Summary of the invention

[0005] The purpose of the present invention is to provide a method for extracting D-ribose from a D-ribose crystallization mother liquor, so as to solve the problem that the existing process for extracting D-ribose from a D-ribose crystallization mother liquor is complicated, the extraction and recovery cost is high, and it is not conducive to reducing the production cost of the enterprise.

[0006] To achieve the above object, the present invention adopts the following technical scheme: a method for extracting D-ribose from D-ribose crystallization mother liquor, comprising the following steps:

[0007] S1. Directly subjecting the crystallization mother liquor containing ethanol to membrane separation through a nanofiltration membrane to obtain a dialysate;

[0008] S2, performing membrane separation on the dialysate obtained in S1 through a molecular sieve membrane to obtain a concentrated solution;

[0009] S3. Add the concentrated solution of S2 into a crystallization tank for crystallization to obtain D-ribose product.

[0010] Furthermore, in the S1, the membrane material of the nanofiltration membrane is polyvinyl alcohol, and the molecular weight cut-off is 400 to 600 Da1.

[0011] Furthermore, the temperature of the crystallization mother liquor is 5-20° C., the mass fraction of D-ribose in the crystallization mother liquor is 5-10%, and the volume fraction of ethanol is 30-40%.

[0012] Furthermore, the volume ratio of the dialysate to the intercepted fluid of the nanofiltration membrane is 1 to 10:1.

[0013] Furthermore, in the S2, the molecular sieve membrane is a NaA type molecular sieve membrane.

[0014] Furthermore, when the dialysate is subjected to membrane separation by the molecular sieve membrane, the temperature of the dialysate is 30 to 80°C, and the operating temperature of the molecular sieve membrane is 30 to 40°C.

[0015] Furthermore, in the S2, the mass fraction of D-ribose in the concentrated solution is 15-25%, and the volume fraction of ethanol is 60-80%.

[0016] Furthermore, in the S3, the concentrated solution is added to the crystallization tank at a ratio of 1:1 to 10.

[0017] Furthermore, the concentrated solution is decolorized by activated carbon before being added to the crystallization tank, and the amount of activated carbon used is 1-5% of the mass of the concentrated solution. After decolorization, it is filtered and then added to the crystallization tank.

[0018] Furthermore, in the above-mentioned S3, after the concentrated solution is added into the crystallization tank, ethanol is added into the crystallization tank so that the volume fraction of ethanol is 30-40%.

[0019] Beneficial effects of the present invention:

[0020] 1. The process flow of the present invention is simple, and the crystallization mother liquor is directly processed without separating the ethanol therein, so the energy consumption of recovering ethanol can be effectively reduced, and the process flow is also simpler, which is helpful to reduce the processing cost;

[0021] 2. The process of the present invention uses a molecular sieve membrane to concentrate the dialysate, which can effectively separate water from the ethanol / water system, and is more energy-saving and environmentally friendly;

[0022] 3. The process of the present invention returns the concentrated liquid treated with the molecular sieve membrane to the crystallizer, and compound it with the fresh fermentation liquid purified concentrated liquid in the crystallizer. During the process, since the concentrated liquid itself contains ethanol, the consumption of ethanol can be greatly reduced, which is more convenient for reducing the production cost of the enterprise. DETAILED DESCRIPTION

[0023] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention.

[0024] Example 1

[0025] The temperature of the D-ribose crystallization mother liquor was 12.1° C. after testing, wherein the mass fraction of D-ribose was 8.4% and the volume fraction of ethanol was 34.7%.

[0026] 1 L of the above D-ribose crystallization mother liquor was taken and subjected to membrane treatment through a nanofiltration membrane. The material of the nanofiltration membrane was polyvinyl alcohol, and the molecular weight cutoff was 400-600 Da1.

[0027] During the nanofiltration membrane treatment, the operating pressure was controlled at 20-25 bar, and finally about 850 mL of dialysate was obtained. After testing, the mass fraction of D-ribose in the dialysate was 9.1%, and the volume fraction of ethanol was 36.3%.

[0028] The obtained dialysate was treated with a molecular sieve membrane to separate water from the dialysate. During the process, the temperature of the dialysate and the operating temperature of the molecular sieve membrane were controlled at 30-40°C, and finally about 430 mL of concentrated solution was obtained, in which the mass fraction of D-ribose was 18.2% and the volume fraction of ethanol was about 70%.

[0029] The obtained concentrated solution was further decolorized by activated carbon and filtered after decolorization. The decolorized concentrated solution was compounded with the purified and concentrated fermentation solution. 530 mL of fermentation solution was taken for compounding with the concentrated solution. The mass fraction of D-ribose in the fermentation solution was 51.8%. After the compounding was completed, 40 mL of ethanol was added to the compounded system. After the compounding was completed, it was tested that the mass fraction of D-ribose in the compounded system was about 38%, and the volume fraction of ethanol was about 35%.

[0030] The above-mentioned composite liquid is directly used for crystallization. A small amount of seed crystals is added during the process, and the temperature is slowly gradually lowered to 5° C. for crystallization to obtain a D-ribose product. After testing, the purity of the D-ribose product is 99.24%, the mass is 329 g, and the yield is about 83%.

[0031] In this embodiment, a product with higher purity and higher yield is finally obtained. In this embodiment, about 330g of product is obtained, and the amount of the product is almost the same as the amount of D-ribose in the compounded fermentation broth. However, in actual production, it is impossible for all the D-ribose in the fermentation broth to be crystallized. Obviously, the method of the present invention can realize the recovery of D-ribose in the crystallization mother liquor. At the same time, the operating cost of the method of the present invention is relatively low, which is about one-fourth of that of the traditional method, and the processing cost of the crystallization mother liquor is significantly reduced.

[0032] Example 2

[0033] 1 L of the crystallization mother liquor from the same batch as in Example 1 was taken and subjected to membrane treatment through a nanofiltration membrane. The material of the nanofiltration membrane was polyvinyl alcohol, and the molecular weight cutoff was 400-600 Da1.

[0034] During the nanofiltration membrane treatment, the operating pressure was controlled at 20-25 bar, and finally about 810 mL of dialysate was obtained. After testing, the mass fraction of D-ribose in the dialysate was 8.9%, and the volume fraction of ethanol was 35.8%.

[0035] The obtained dialysate was treated with a molecular sieve membrane to separate water from the dialysate. During the process, the temperature of the dialysate was controlled at 50-60°C, and the operating temperature of the molecular sieve membrane was controlled at 30-40°C (increasing the distance between the membrane assembly and the dialysate). Finally, about 400 mL of concentrated solution was obtained, in which the mass fraction of D-ribose was 19.7% and the volume fraction of ethanol was about 70%.

[0036] The obtained concentrated solution is further decolorized by activated carbon and filtered after decolorization. The decolorized concentrated solution is compounded with the purified and concentrated fermentation solution. 540 mL of fermentation solution (50-60° C.) is taken to compound with the concentrated solution. The mass fraction of D-ribose in the fermentation solution is 60.4%. After the compounding is completed, 60 mL of ethanol is added to the compounded system. After the compounding is completed, it is tested that the mass fraction of D-ribose in the compounded system is about 45%, and the volume fraction of ethanol is about 35%.

[0037] The above-mentioned composite liquid is directly used for crystallization. A small amount of seed crystals is added during the process, and the temperature is slowly gradually lowered to 5° C. for crystallization to obtain a D-ribose product. After testing, the purity of the D-ribose product is 99.07%, the mass is 386 g, and the yield is about 84%.

[0038] Example 3

[0039] 1 L of the crystallization mother liquor from the same batch as in Example 1 was taken and subjected to membrane treatment through a nanofiltration membrane. The material of the nanofiltration membrane was polyvinyl alcohol, and the molecular weight cutoff was 400-600 Da1.

[0040] During the nanofiltration membrane treatment, the operating pressure was controlled at 20-25 bar, and finally about 850 mL of dialysate was obtained. After testing, the mass fraction of D-ribose in the dialysate was 9.2%, and the volume fraction of ethanol was 36.4%.

[0041] The obtained dialysate was treated with a molecular sieve membrane to separate water from the dialysate. During the process, the temperature of the dialysate was controlled at 70-80°C, and the operating temperature of the molecular sieve membrane was controlled at 30-40°C (increasing the distance between the membrane assembly and the dialysate). Finally, about 410 mL of concentrated solution was obtained, in which the mass fraction of D-ribose was 21.1% and the volume fraction of ethanol was about 75%.

[0042] The obtained concentrated solution is further decolorized by activated carbon and filtered after decolorization. The decolorized concentrated solution is compounded with the purified and concentrated fermentation solution. 550 mL of fermentation solution (70-80° C.) is taken to compound with the concentrated solution. The mass fraction of D-ribose in the fermentation solution is 68.8%. After the compounding is completed, 40 mL of ethanol is added to the compounded system. After the compounding is completed, it is tested that the mass fraction of D-ribose in the compounded system is about 50%, and the volume fraction of ethanol is about 35%.

[0043] The above-mentioned composite liquid is directly used for crystallization. A small amount of seed crystals is added during the process, and the temperature is slowly gradually lowered to 5° C. for crystallization to obtain a D-ribose product. After testing, the purity of the D-ribose product is 99.16%, the mass is 452 g, and the yield is about 85%.

[0044] Example 4

[0045] 1 L of the crystallization mother liquor from the same batch as in Example 1 was taken and subjected to membrane treatment through a nanofiltration membrane. The material of the nanofiltration membrane was polyvinyl alcohol, and the molecular weight cutoff was 400-600 Da1.

[0046] During the nanofiltration membrane treatment, the operating pressure was controlled at 20-25 bar, and finally about 830 mL of dialysate was obtained. After testing, the mass fraction of D-ribose in the dialysate was 9.1%, and the volume fraction of ethanol was 36.2%.

[0047] The obtained dialysate was treated with a molecular sieve membrane to separate water from the dialysate. During the process, the temperature of the dialysate and the operating temperature of the molecular sieve membrane were controlled at 30-40°C, and finally about 440 mL of concentrated solution was obtained, in which the mass fraction of D-ribose was 18.3% and the volume fraction of ethanol was about 68%.

[0048] The obtained concentrated solution is further decolorized by activated carbon and filtered after decolorization. The decolorized concentrated solution is compounded with the purified and concentrated fermentation solution. 510 mL of fermentation solution (70-80° C.) is taken to compound with the concentrated solution. The mass fraction of D-ribose in the fermentation solution is 69.6%. After the compounding is completed, 50 mL of ethanol is added to the compounded system. After the compounding is completed, it is tested that the mass fraction of D-ribose in the compounded system is about 48%, and the volume fraction of ethanol is about 35%.

[0049] The above-mentioned composite liquid is directly used for crystallization. A small amount of seed crystals is added during the process, and the temperature is slowly gradually lowered to 5° C. for crystallization to obtain a D-ribose product. After testing, the purity of the D-ribose product is 99.20%, the mass is about 421 g, and the yield is about 85%.

[0050] The present invention is not limited to the above-mentioned optimal implementation mode. Anyone can derive other various forms of products under the inspiration of the present invention. However, no matter what changes are made in the shape or structure, all technical solutions that are the same or similar to those of the present application fall within the protection scope of the present invention.

Claims

1. A method for extracting D-ribose from D-ribose crystallization mother liquor, characterized in that: The following steps are involved: S1. Directly subjecting the crystallization mother liquor containing ethanol to membrane separation through a nanofiltration membrane to obtain a dialysate; S2, performing membrane separation on the dialysate obtained in S1 through a molecular sieve membrane to obtain a concentrated solution; S3. Add the concentrated solution of S2 into a crystallization tank for crystallization to obtain D-ribose product.

2. The method for extracting D-ribose from D-ribose crystallization mother liquor according to claim 1, characterized in that: In the above-mentioned S1, the membrane material of the nanofiltration membrane is polyvinyl alcohol, and the molecular weight cut-off is 400-600 Da1.

3. The method for extracting D-ribose from D-ribose crystallization mother liquor according to claim 2, characterized in that: The temperature of the crystallization mother liquor is 5-20° C., the mass fraction of D-ribose in the crystallization mother liquor is 5-10%, and the volume fraction of ethanol is 30-40%.

4. The method for extracting D-ribose from D-ribose crystallization mother liquor according to claim 3, characterized in that: The volume ratio of the dialysate to the intercepted fluid of the nanofiltration membrane is 1 to 10:

1.

5. The method for extracting D-ribose from D-ribose crystallization mother liquor according to claim 1, characterized in that: In the S2, the molecular sieve membrane is a NaA type molecular sieve membrane.

6. The method for extracting D-ribose from D-ribose crystallization mother liquor according to claim 5, characterized in that: When the dialysate is subjected to membrane separation by the molecular sieve membrane, the temperature of the dialysate is 30-80°C, and the operating temperature of the molecular sieve membrane is 30-40°C.

7. The method for extracting D-ribose from D-ribose crystallization mother liquor according to any one of claims 1 to 6, characterized in that: In the S2, the mass fraction of D-ribose in the concentrated solution is 15-25%, and the volume fraction of ethanol is 60-80%.

8. The method for extracting D-ribose from D-ribose crystallization mother liquor according to claim 7, characterized in that: In the above-mentioned S3, the concentrated solution is added into the crystallization tank at a ratio of 1:1 to 10.

9. The method for extracting D-ribose from D-ribose crystallization mother liquor according to claim 8, characterized in that: The concentrated solution is decolorized by activated carbon before being added to the crystallization tank. The amount of activated carbon used is 1-5% of the mass of the concentrated solution. After decolorization, the concentrated solution is filtered and then added to the crystallization tank.

10. The method for extracting D-ribose from D-ribose crystallization mother liquor according to claim 9, characterized in that: In the above-mentioned S3, after the concentrated solution is added into the crystallization tank, ethanol is added into the crystallization tank so that the volume fraction of ethanol is 30-40%.