Method for preparing fructose disodium phosphate by using waste beer yeast

Abstract

The invention provides a method for preparing fructose disodium phosphate by using waste beer yeast, and belongs to the technical field of organic synthesis. Comprising the following steps: (1) adding pure water into a reaction kettle, and then adding glucose, sodium dihydrogen phosphate, magnesium chloride and ammonium chloride into the pure water to obtain a reaction substrate; (2) adding waste beer yeast and ATP (adenosine triphosphate) into the reaction substrate, and reacting to obtain fermentation liquor; (3) filtering the fermentation liquor by using a ceramic membrane, and then adding activated carbon powder for adsorption; and (4) carrying out primary compression, desalination and concentration on the material through a nanofiltration membrane, removing residual monovalent ions through an electrodialysis device, and further concentrating through the nanofiltration membrane to obtain the fructose disodium phosphate solution. According to the method provided by the invention, a route of low-pressure nanofiltration preliminary compression-electrodialysis desalination-high-pressure nanofiltration concentration is adopted in a rear-section desalination and concentration stage, so that the purposes of separation and purification are achieved, the treatment speed is high, the operation cost is low, and industrial and large-scale production is easy to realize.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis, and particularly relates to a method for preparing disodium fructose phosphate by utilizing waste beer yeast. Background Art

[0002] Fructose 1,6-bisphosphate (FDP) is an important biochemical substance that plays a key role in the intracellular sugar metabolism process. It is a key intermediate in the glycolysis pathway. It is produced in the second step of glycolysis by the phosphorylation reaction of fructose 6-phosphate catalyzed by 6-phosphofructokinase-1 (PFK-1). It is used as an enzyme and biochemical drug in clinical practice, mainly for the treatment of cardiovascular diseases such as angina pectoris caused by coronary heart disease, acute myocardial infarction, heart failure and arrhythmia. Recent studies have shown that fructose 1,6-bisphosphate is also used as an auxiliary treatment for myocardial damage caused by hyperkalemia, acute adult respiratory distress syndrome, dilated cardiomyopathy, parenteral nutrition, and extracorporeal circulation in cardiac surgery.

[0003] Chinese patent CN1041327A discloses a method for producing FDP by microbial fermentation that can improve the yield and purity of FDP. Glucose and sodium dihydrogen phosphate are used as substrates for fermentation with brewer's yeast, benzyl ammonium bromide is added as an aldolase inhibitor to promote the accumulation of FDP, the fermentation liquid is diluted and directly extracted on an anion resin column, impurities are eluted with dilute hydrochloric acid, and FDP is purified by ethanol crystallization to become FDP trisodium salt containing eight crystal waters. The fermentation conversion rate of the invention reaches 88% based on inorganic phosphorus consumption, the FDP fermentation unit reaches about 40,000r, the purity of the FDP product reaches 99%, and the success rate of continuous pilot production after dozens of batches is 98.6%. The process is stable and suitable for industrial production.

[0004] The existing FDP preparation process has the following deficiencies: (1) The yeast addition amount is relatively high, at the level of 180-200 g / L, which is costly; (2) It cannot meet the needs of industrial continuous production. In the reaction system with low waste yeast addition during the fermentation process, the reaction initiation and progress are limited by the concentration of glucose and phosphate, and glucose and sodium dihydrogen phosphate need to be maintained at a stable level by batch addition; (3) The fermentation broth is filtered through a ceramic membrane, and there are protein and amino acid residues. It needs to be purified by anion column ion exchange, and FDP is adsorbed on the anion column and then eluted with a specific concentrated sodium chloride solution to obtain a salt-containing FDP solution. This purification step is limited by the resin selection and must be carried out under specific acidic conditions. The operation is complicated and the material acidification and Resin regeneration produces a large amount of high-chloride wastewater, which has high treatment costs; (4) After the resin adsorption is completed, 8-10% sodium chloride solution is required for elution, and some chloride ions enter the wastewater. The chloride content in the wastewater is high and difficult to treat; (5) In the nanofiltration desalination concentration stage, due to the high sodium chloride content in the material, the load of nanofiltration desalination treatment is large, and in the nanofiltration water dialysis stage, 5-10 times the volume of the concentrated solution with a salt content of 2%-3% nanofiltration clear liquid will be produced, and it contains trace amounts of FDP materials. This part of the clear liquid needs to be concentrated before it can be reused to maintain the balance of the system. Because the FDP material has poor thermal sensitivity, it is not suitable for conventional vacuum concentration; if concentration and reuse are not considered, the wastewater treatment will have the problem of high COD and chloride ions, which is difficult to treat, large in volume, and high in cost.

[0005] In view of the shortcomings of the existing process, it is necessary to develop a method for preparing disodium fructose phosphate with low yeast addition and capable of achieving industrial continuous production. Summary of the invention

[0006] Based on the deficiencies in the prior art, the purpose of the present invention is to provide a method for preparing disodium fructose phosphate with low yeast addition amount and capable of realizing industrial continuous production, aiming to solve the problems existing in the existing FDP production and preparation process, such as high cost of high-density yeast addition amount, difficulty in initiating reaction of low-density yeast addition amount, complex process operation, high cost of sewage treatment, large workload of salt removal and recovery, and high labor intensity.

[0007] In order to achieve the above object, the present invention adopts the following technical scheme:

[0008] A method for preparing disodium fructose phosphate using waste beer yeast comprises the following steps:

[0009] (1) adding pure water to a reaction kettle, and then adding glucose, sodium dihydrogen phosphate, magnesium chloride, and ammonium chloride to the pure water to obtain a reaction substrate;

[0010] (2) adding waste beer yeast and ATP to the reaction system of step (1), adjusting the pH value to 6.5-6.8, adjusting the temperature to 35-38° C., and adjusting the rotation speed to 75-100 rpm, and reacting. After the reaction is completed, a fermentation liquid is obtained;

[0011] (3) filtering the fermentation liquid obtained in step (2) with a ceramic membrane to remove bacteria and protein, collecting the clear liquid, adding hydrochloric acid to the clear liquid to adjust the pH value to 2.0-2.5, then adding activated carbon powder and stirring at 25-28° C. for 1-1.5 h to allow the residual protein in the clear liquid to further precipitate and be adsorbed by the activated carbon, and filtering to obtain a clarified FDP material containing impurities;

[0012] (4) The FDP material containing impurities obtained in step (3) is subjected to preliminary compression desalination and concentration through a nanofiltration membrane at 25-28° C. and 2.5-3.0 MPa, the volume of the stock solution is compressed 4-6 times to make the FDP content reach 120-150 g / L, and then the residual monovalent ions are removed through an electrodialysis device at 15-20 V, a current of 2.0-2.2 A, and 25-28° C. to obtain a high-purity desalted FDP material;

[0013] (5) The desalted FDP material obtained in step (4) is further concentrated through a nanofiltration membrane at 25-28° C. and 7.5-8.0 MPa to a FDP content of 280-320 g / L to obtain the disodium fructose phosphate solution, and the product is barreled and stored at 5-10° C.

[0014] The total amount of glucose added in the above method is 90-100 g / L, the total amount of sodium dihydrogen phosphate added is 48-50 g / L, the total amount of magnesium chloride added is 10-12 g / L, the total amount of ammonium chloride added is 1.8-2.0 g / L, the total amount of waste brewer's yeast added is 80-100 g / L, and the total amount of ATP added is 150-180 mg / L.

[0015] As a preferred embodiment, the glucose and sodium dihydrogen phosphate are added to the reactor in the form of reaction substrates and supplementary additions; in the reaction substrate described in step (1), the amount of glucose added is 45-50 g / L, the amount of sodium dihydrogen phosphate added is 24-25 g / L, the amount of magnesium chloride added is 10-12 g / L, and the amount of ammonium chloride added is 1.8-2.0 g / L.

[0016] The amount of waste beer yeast added in step (2) is 80-100 g / L, and the amount of ATP added is 150-180 mg / L.

[0017] The amount of pure water added in the above step (1) is 70%-75% of the volume of the reaction kettle.

[0018] The adjusting agent used for adjusting the pH value in the above step (2) is a 10%-16% sodium hydroxide solution.

[0019] The residual sugar value needs to be detected during the reaction described in the above step (2). The residual sugar is controlled at 50 g / L by adding glucose and sodium dihydrogen phosphate 4 hours before the reaction until the addition is completed. The reaction is continued until the residual sugar is 0. The total reaction time is 8-10 hours.

[0020] During the reaction in step (2), a sodium hydroxide solution is used to adjust the pH value to maintain at 6.5-6.8.

[0021] The pore size of the ceramic membrane in the above step (3) is 50 nm; the filtration temperature of the ceramic membrane is 25-28°C.

[0022] The activated carbon described in the above step (3) is acidic activated carbon, and the pH value of the acidic activated carbon is 3.0-3.5; the amount of the acidic activated carbon added is 1-2% of the mass of the clear liquid; preferably 1%.

[0023] The filtration described in the above step (3) is filtration using a plate and frame filter pre-coated with perlite.

[0024] The pore size of the nanofiltration membrane described in the above steps (4) and (5) is 100-120Da.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) The method provided by the present invention adopts staged addition of nutrients during the fermentation process, so that the concentrations of glucose and phosphate in the low yeast addition system are maintained at a stable level suitable for yeast metabolism to produce FDP, thereby avoiding the reaction inhibition caused by excessively high substrate concentration in conventional fermentation;

[0027] (2) The method provided by the present invention optimizes the separation and purification process, and uses the acid precipitation filtration method to remove residual proteins and amino acids in the ceramic membrane clear liquid to achieve the purpose of purification, replacing the resin purification process in the existing conventional process, overcoming the problems of the existing resin separation technology with complex operation, large amount of sewage generated, and high sewage treatment cost. The process is simple, the cycle is short, the cost is low, the product yield is high, and there are few by-products;

[0028] (3) The method provided by the present invention adopts a route of low-pressure nanofiltration preliminary compression-electrodialysis desalination-high-pressure nanofiltration concentration in the latter stage of desalination and concentration. The electrodialysis method is used to perform electrodialysis treatment on the material after preliminary nanofiltration compression to remove a small amount of salt ions in the solution to achieve the purpose of separation and purification. The processing load is small, the processing speed is fast, the operating cost is low, and it is easy to realize industrialization and large-scale production. The conventional resin separation and exchange section uses a concentrated sodium chloride solution to elute the pure FDP product, which needs to be removed in the nanofiltration stage. The nanofiltration desalination step requires the addition of 5-10 times the amount of pure water for washing. The washing process produces a large amount of low-concentration salt water containing a small amount of FDP material. This part of the material needs to be concentrated to balance the system to reach the reuse concentration. In addition, conventional negative pressure concentration will cause a small amount of FDP to decompose and produce impurities, affecting the stability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The present invention provides a flow chart for preparing disodium fructose phosphate using waste brewer's yeast. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] Example 1 Method for preparing disodium fructose phosphate using waste beer yeast

[0032] Reactor: 5000L, the amount of pure water added is 70% of the volume of the reactor;

[0033] The total amount of reactants added: glucose 90g / L, sodium dihydrogen phosphate 48g / L, waste brewer's yeast 80g / L, magnesium chloride 10g / L, ammonium chloride 1.8g / L and ATP 150mg / L.

[0034] Reaction steps:

[0035] (1) adding 3500 L of pure water to a 5000 L reactor, and then adding 45 g / L of glucose, 24 g / L of sodium dihydrogen phosphate, 10 g / L of magnesium chloride, and 1.8 g / L of ammonium chloride to the pure water to obtain a reaction substrate;

[0036] (2) 80 g / L of waste brewer's yeast and 150 mg / L of ATP were added to the reaction system of step (1), and the pH value was adjusted to 6.5-6.8 with 16% sodium hydroxide solution, the temperature was adjusted to 35-38° C., the rotation speed was 75 rpm, and the reaction was carried out. The residual sugar value was monitored during the process. The residual sugar was controlled at 50 g / L by adding glucose and sodium dihydrogen phosphate 4 hours before the reaction until it was completed. The residual sugar was 0 after 9 hours of reaction. After the reaction, the obtained fermentation liquid was sampled and the FDP content was 61 g / L;

[0037] (3) The fermentation liquid obtained in step (2) was filtered at 25°C with a 50nm pore size ceramic membrane to remove bacteria and protein, and 3000L of clear liquid was collected. The clear liquid was sampled and tested for FDP content of 25g / L. Hydrochloric acid was added to adjust the pH to 2.0, and 0.5% activated carbon powder with a pH of 3.5 was added and stirred at 25°C for 1h to allow the residual protein in the clear liquid to further precipitate and be adsorbed by the acidic activated carbon. The material in the previous step was filtered using a plate and frame filter pre-coated with perlite to obtain a clarified FDP material containing impurities; the FDP material containing impurities before and after treatment was tested for protein. The protein content of the material before treatment was 20mg / L, and the protein content of the material after treatment was 1.5mg / L. 30kg of activated carbon filter residue was produced in a batch, no wastewater was generated, and the cost of activated carbon solid waste treatment was about 150 yuan;

[0038] (4) The salt-containing FDP material obtained in step (3) is subjected to preliminary compression desalination and concentration through a nanofiltration membrane at 25° C. and 2.5 MPa, the volume of the stock solution is compressed 5 times to make the FDP content reach 125 g / L, and then the residual monovalent ions are removed through an electrodialysis device at 20 V, 2.0 A, and 25° C. to obtain a high-purity desalted FDP material;

[0039] (5) The desalted FDP material obtained in step (4) is further concentrated through a nanofiltration membrane at 25° C. and 7.5 MPa until the FDP content reaches 280 g / L to obtain the disodium fructose phosphate solution, and the product is barreled and stored at 5-10° C.

[0040] Example 2 Method for preparing disodium fructose phosphate using waste beer yeast

[0041] Reactor: 5000L, the amount of pure water added is 75% of the volume of the reactor;

[0042] The total amount of reactants added: glucose 100 g / L, sodium dihydrogen phosphate 50 g / L, waste brewer's yeast 100 g / L, magnesium chloride 12 g / L, ammonium chloride 2.0 g / L and ATP 180 mg / L.

[0043] Reaction steps:

[0044] (1) adding 3500 L of pure water to a 5000 L reactor, and then adding 50 g / L of glucose, 25 g / L of sodium dihydrogen phosphate, 12 g / L of magnesium chloride, and 2.0 g / L of ammonium chloride to the pure water to obtain a reaction substrate;

[0045] (2) 100 g / L of waste brewer's yeast and 180 mg / L of ATP were added to the reaction system of step (1), and the pH value was adjusted to 6.5-6.8 with 16% sodium hydroxide solution, the temperature was adjusted to 35-38° C., the rotation speed was 100 rpm, and the reaction was carried out. The residual sugar value was monitored during the process. Glucose and sodium dihydrogen phosphate were added 4 hours before the reaction to control the residual sugar at 50 g / L until it was completed. The residual sugar was 0 after 7 hours of reaction. After the reaction, the obtained fermentation liquid was sampled and tested for FDP content of 65 g / L;

[0046] (3) The fermentation liquid obtained in step (2) was filtered at 28°C with a 50 nm pore size ceramic membrane to remove bacteria and protein, and 2800 L of clear liquid was collected. The clear liquid was sampled for FDP content detection, which was 28 g / L. Hydrochloric acid was added to adjust the pH to 2.5, and 0.5% activated carbon powder with a pH of 3.0 was added and stirred at 28°C for 1.5 hours to allow the residual protein in the clear liquid to further precipitate and be adsorbed by the acidic activated carbon. The material in the previous step was filtered using a plate and frame filter pre-coated with perlite to obtain a clarified FDP material containing impurities; the FDP material containing impurities before and after treatment was tested for protein. The protein content of the material before treatment was 22.5 mg / L, and the protein content of the material after treatment was 1.23 mg / L. The batch produced 33 kg of activated carbon filter residue, no wastewater was generated, and the cost of activated carbon solid waste treatment was about 165 yuan;

[0047] (4) The FDP material containing impurities obtained in step (3) is subjected to preliminary compression desalination and concentration through a nanofiltration membrane at 28° C. and 3.0 MPa, the volume of the original solution is compressed by 6 times to make the FDP content reach 150 g / L, and then the residual monovalent ions are removed through an electrodialysis device at 20 V, current 2.2 A, and 28° C. to obtain a high-purity desalted FDP material;

[0048] (5) The desalted FDP material obtained in step (4) is further concentrated through a nanofiltration membrane at 28° C. and 8.0 MPa until the FDP content reaches 320 g / L to obtain the disodium fructose phosphate solution, and the product is barreled and stored at 5-10° C.

[0049] Comparative Example 1

[0050] Reactor: 5000L, the amount of pure water added is 75% of the volume of the reactor;

[0051] The total amount of reactants added: glucose 100 g / L, sodium dihydrogen phosphate 50 g / L, waste brewer's yeast 100 g / L, magnesium chloride 12 g / L, ammonium chloride 2.0 g / L and ATP 180 mg / L.

[0052] Reaction steps:

[0053] (1) adding 3500 L of pure water to a 5000 L reactor, and then adding 100 g / L of glucose, 50 g / L of sodium dihydrogen phosphate, 12 g / L of magnesium chloride, and 2.0 g / L of ammonium chloride to the pure water at one time to obtain a reaction substrate;

[0054] (2) 100 g / L of waste brewer's yeast and 180 mg / L of ATP were added to the reaction system of step (1), and the pH value was adjusted to 6.5-6.8 with 16% sodium hydroxide solution, the temperature was adjusted to 35-38° C., the rotation speed was 100 rpm, and the reaction was carried out. The residual sugar value was monitored during the process. After 2 hours of reaction, the system did not consume obvious alkali. The initial residual sugar was 100 g / L. After the residual sugar dropped to 85 g / L, there was no change. The FDP content of the fermentation liquid after 10 hours was sampled and tested, and the content was 5.6 g / L. The FDP content was too low, and no subsequent experiments were performed.

[0055] Comparative Example 2

[0056] Reactor: 5000L, the amount of pure water added is 75% of the volume of the reactor;

[0057] The total amount of reactants added: glucose 100 g / L, sodium dihydrogen phosphate 50 g / L, waste brewer's yeast 100 g / L, magnesium chloride 12 g / L, ammonium chloride 2.0 g / L and ATP 180 mg / L.

[0058] Reaction steps:

[0059] (1) adding 3500 L of pure water to a 5000 L reactor, and then adding 50 g / L of glucose, 25 g / L of sodium dihydrogen phosphate, 12 g / L of magnesium chloride, and 2.0 g / L of ammonium chloride to the pure water to obtain a reaction substrate;

[0060] (2) 100 g / L of waste brewer's yeast and 180 mg / L of ATP were added to the reaction system of step (1), and the pH value was adjusted to 6.5-6.8 with 16% sodium hydroxide solution, the temperature was adjusted to 35-38° C., the rotation speed was 100 rpm, and the reaction was carried out. The residual sugar value was monitored during the process. Glucose and sodium dihydrogen phosphate were added 4 hours before the reaction to control the residual sugar at 50 g / L until it was completed. The residual sugar was 0 after 7 hours of reaction. After the reaction, the obtained fermentation liquid was sampled and tested for FDP content of 65 g / L;

[0061] (3) The fermentation broth obtained in step (2) was filtered at 28°C using a 50 nm pore size ceramic membrane to remove bacteria and protein, and 2800 L of clear liquid was collected. The clear liquid was sampled and tested for FDP content, which was 28 g / L. The ceramic membrane filtrate was purified using a weakly alkaline anion exchange resin column. The pH of the sample solution was 2.0. After the adsorption was completed, 6000 L of 0.8 mol / L sodium chloride solution was used for impurity washing. After the washing was completed, 3000 L of 1.8 mol / L sodium chloride solution was used for FDP elution to obtain an eluate with an FDP content of 15 g / L. The clear liquid before and after the treatment was tested for protein. The protein content of the clear liquid before the treatment was 25 mg / L, and the protein content of the clear liquid after the treatment was 0.525 mg / L. Converted to the same FDP concentration in Example 2, the protein content is 0.98 mg / L, no waste residue is generated, 6000 L of washing wastewater and 5000 L of regeneration wastewater are produced, the average chloride ion in the wastewater is 12000 ppm, reaching the treatment standard of 2000 ppm diluted 6 times, the total water volume is 66 cubic meters, and the wastewater treatment cost is about 660 yuan.

[0062] In summary, the method provided by the present invention optimizes the separation and purification process, utilizes the acid precipitation filtration method to remove residual proteins and amino acids in the ceramic membrane clear liquid, achieves the purpose of purification, replaces the resin purification process in the existing conventional process, overcomes the problems of complex operation, large amount of sewage generation, and high sewage treatment cost of the existing resin separation and cross-linking technology, and has simple process, short cycle, low cost, high product yield and few by-products; in the latter desalination and concentration stage, a route of low-pressure nanofiltration preliminary compression-electrodialysis desalination-high-pressure nanofiltration concentration is adopted, and an electrodialysis method is adopted to perform electrodialysis treatment on the material after preliminary nanofiltration compression to remove a small amount of salt ions in the solution to achieve the purpose of separation and purification, with small processing load, fast processing speed, low operating cost, and easy industrialization and large-scale production.

Claims

1. A method for preparing disodium fructose phosphate using waste brewer's yeast, characterized in that: The steps include: (1) adding pure water to a reaction kettle, and then adding glucose, sodium dihydrogen phosphate, magnesium chloride, and ammonium chloride to the pure water to obtain a reaction substrate; (2) adding waste beer yeast and ATP to the reaction system of step (1), adjusting the pH value to 6.5-6.8, adjusting the temperature to 35-38° C., and adjusting the rotation speed to 75-100 rpm, and reacting. After the reaction is completed, a fermentation liquid is obtained; (3) filtering the fermentation liquid obtained in step (2) with a ceramic membrane to remove bacteria and protein, collecting the clear liquid, adding hydrochloric acid to the clear liquid to adjust the pH value to 2.0-2.5, then adding activated carbon powder and stirring at 25-28° C. for 1-1.5 h to allow the residual protein in the clear liquid to further precipitate and be adsorbed by the activated carbon, and filtering to obtain a clarified FDP material containing impurities; (4) The FDP material containing impurities obtained in step (3) is subjected to preliminary compression desalination and concentration through a nanofiltration membrane at 25-28° C. and 2.5-3.0 MPa, the volume of the stock solution is compressed 4-6 times to make the FDP content reach 120-150 g / L, and then the residual monovalent ions are removed through an electrodialysis device at 15-20 V, a current of 2.0-2.2 A, and 25-28° C. to obtain a high-purity desalted FDP material; (5) The desalted FDP material obtained in step (4) is further concentrated through a nanofiltration membrane at 25-28° C. and 7.5-8.0 MPa to a FDP content of 280-320 g / L to obtain the disodium fructose phosphate solution, and the product is barreled and stored at 5-10° C.

2. The method according to claim 1, characterized in that: The total amount of glucose added is 90-100 g / L, the total amount of sodium dihydrogen phosphate added is 48-50 g / L, the total amount of magnesium chloride added is 10-12 g / L, the total amount of ammonium chloride added is 1.8-2.0 g / L, the total amount of waste brewer's yeast added is 80-100 g / L, and the total amount of ATP added is 150-180 mg / L.

3. The method according to claim 1, characterized in that: The glucose and sodium dihydrogen phosphate are added into the reaction kettle in the form of reaction substrates and supplementary additions.

4. The method according to claim 1, characterized in that: The amount of glucose added to the reaction substrate in step (1) is 45-50 g / L, the amount of sodium dihydrogen phosphate added is 24-25 g / L, the amount of magnesium chloride added is 10-12 g / L, and the amount of ammonium chloride added is 1.8-2.0 g / L.

5. The method according to claim 1, characterized in that: The amount of waste beer yeast added in step (2) is 80-100 g / L, and the amount of ATP added is 150-180 mg / L.

6. The method according to claim 1, characterized in that: The amount of pure water added in step (1) is 70%-75% of the volume of the reaction kettle.

7. The method according to claim 1, characterized in that: The adjusting agent used for adjusting the pH value in step (2) is a 10%-16% sodium hydroxide solution.

8. The method according to claim 1, characterized in that: During the reaction described in step (2), the residual sugar value needs to be detected. 4 hours before the reaction, the residual sugar is controlled at 50 g / L by adding glucose and sodium dihydrogen phosphate until the addition is complete. The reaction is continued until the residual sugar is 0. The total reaction time is 8-10 hours.

9. The method according to claim 1, characterized in that: In the reaction described in step (2), the pH value needs to be regulated and maintained at 6.5-6.8 using sodium hydroxide solution during the reaction.

10. The method according to claim 1, characterized in that: The pore size of the ceramic membrane in step (3) is 50 nm; the filtration temperature of the ceramic membrane is 25-28°C.

11. The method according to claim 1, characterized in that: The activated carbon described in step (3) is acidic activated carbon, and the pH value of the acidic activated carbon is 3.0-3.5; the amount of the acidic activated carbon added is 1-2% of the mass of the clear liquid.

12. The method according to claim 1, characterized in that: The filtration described in step (3) is filtration using a plate and frame filter pre-coated with perlite.

13. The method according to claim 1, characterized in that: The pore size of the nanofiltration membrane described in step (4) and step (5) is 100-120Da.

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