A method for preparing vitamin C

Abstract

The present invention relates to a method for preparing vitamin C. The method comprises: dissolving 2-keto-L-gulonic acid in water to obtain a keto-gulonic acid solution; adding a catalyst composed of palladium acetate, citric acid, and L-alanine to the keto-gulonic acid solution; reacting at 30-35 degrees Celsius for 1-2 hours; heating to 50-55 degrees Celsius; and after the reaction is carried out for 20 hours, stopping heating and unloading to obtain a solid liquid containing vitamin C; cooling the solid liquid containing vitamin C at room temperature for crystallization for 4-6 hours, and then using centrifugal separation and purification to obtain vitamin C. The process for preparing vitamin C using the scheme of the present invention is simpler and more efficient.

Description

Technical Field

[0001] The present invention relates to a method for preparing vitamin C. Background Art

[0002] Vitamin C, also known as ascorbic acid, is a water-soluble vitamin with important physiological functions. It can promote iron absorption, enhance immunity, resist oxidation, and reduce inflammation. Vitamin C deficiency can lead to diseases such as scurvy.

[0003] Vitamin C is produced primarily through synthetic and natural extraction methods. Early on, vitamin C was typically extracted from citrus fruits. Later, with the development of synthetic processes, chemical synthesis began to be used, significantly reducing production costs. Currently, synthetic methods are the predominant method for producing vitamin C.

[0004] Vitamin C is synthesized using carbohydrates such as glucose or starch through a multi-step chemical reaction. This method has been widely used in industrial production. Biotechnology-based methods, such as fermentation-based extraction of vitamin C from microorganisms, have also been applied in specific fields.

[0005] In summary, the preparation methods of vitamin C cover a variety of different fields such as chemistry and biotechnology, among which synthesis is one of the most widely used methods. Among the synthesis methods in the prior art, most of the synthesis processes are complex and inefficient. Summary of the Invention

[0006] The purpose of the present invention is to address the deficiencies in the prior art and provide a method for preparing vitamin C, which comprises the following steps:

[0007] dissolving 2-keto-L-gulonic acid in water to obtain a ketogulonic acid solution;

[0008] Adding a catalyst consisting of palladium acetate, citric acid, and L-alanine to the ketogulonic acid solution and reacting at 30-35 degrees Celsius for 1-2 hours;

[0009] Heat to 50-55°C, react for 20 hours, stop heating and discharge the material to obtain a solid liquid containing vitamin C;

[0010] The solid-liquid containing vitamin C is cooled and crystallized at room temperature for 4-6 hours, and then centrifuged and purified to obtain vitamin C.

[0011] As a preferred technical solution, the content of 2-keto-L-gulonic acid in the ketogulonic acid solution is 300-500 g / L.

[0012] As a preferred technical solution, the amount of the catalyst used is 1.5-3 g / L.

[0013] As a preferred technical solution, the mass ratio of palladium acetate, citric acid and L-alanine is 1:(15-30):(5-20).

[0014] As a preferred technical solution, the preparation steps of 2-keto-L-gulonic acid include:

[0015] Add fermentation medium to the fermentation tank;

[0016] The inoculum was inoculated with a mixed seed solution of Pantoea ananatis and Gluconobacter oxydans;

[0017] Add sorbitol solution dropwise to control the sorbitol concentration in the fermenter between 15-20 g / L;

[0018] Add sodium carbonate dropwise to control the pH at 6.7-6.8;

[0019] Ferment for 20-30 hours, maintaining a constant temperature of 30°C.

[0020] As a preferred technical solution, the concentration of sorbitol in the sorbitol solution is 600 mg / L.

[0021] As a preferred technical solution, the mass ratio of Pantoea ananatis to Gluconobacter oxydans is 2-4:1.

[0022] As a preferred technical solution, the fermentation medium formula is: sorbitol 20-25g / L, yeast extract 2-3g / L, corn steep liquor 10-15g / L, urea 4-7g / L, magnesium sulfate 0.6-1g / L, calcium carbonate 8-15g / L, prepared with water.

[0023] Vitamin C prepared by the above method.

[0024] The use of Pantoea ananas and Gluconobacter oxidans has a higher conversion rate, and the use of palladium acetate, citric acid and L-alanine also has a good synergistic effect, which can greatly improve the conversion rate of the reaction. DETAILED DESCRIPTION

[0025] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the examples described are part of the embodiments of the present invention, not all of the embodiments. Based on the described 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.

[0026] Unless otherwise defined, technical or scientific terms used herein shall have the ordinary meaning as understood by persons of ordinary skill in the art to which this invention pertains. The terms "first," "second," and similar terms used in the present patent application specification and claims do not denote any order, quantity, or importance, but are merely used to distinguish different components. Similarly, terms such as "a" or "an" do not denote a limitation of quantity, but rather denote the presence of at least one.

[0027] The method for preparing vitamin C of the present invention comprises the following steps:

[0028] 2-keto-L-gulonic acid is dissolved in water to obtain a keto-gulonic acid solution. A catalyst consisting of palladium acetate, citric acid, and L-alanine is added to the keto-gulonic acid solution and reacted at 30-35 degrees Celsius for 1-2 hours. The solution is heated to 50-55 degrees Celsius and allowed to react for 20 hours. The reaction is then stopped and the solution is discharged to obtain a solid solution containing vitamin C. The solid solution containing vitamin C is cooled and crystallized at room temperature for 4-6 hours, followed by centrifugation and purification to obtain vitamin C. In a preferred embodiment, the keto-gulonic acid solution contains 300-500 g / L of 2-keto-L-gulonic acid. In a preferred embodiment, the catalyst is used in an amount of 1.5-3 g / L. In a preferred embodiment, the mass ratio of palladium acetate, citric acid, and L-alanine is 1:(15-30):(5-20).

[0029] As a preferred embodiment, the preparation steps of 2-keto-L-gulonic acid include:

[0030] A fermentation medium is added to a fermentor, inoculated with a mixed seed solution of Pantoea ananatis and Gluconobacter oxydans; a sorbitol solution is added dropwise to control the sorbitol concentration in the fermentor to between 15-20 g / L; sodium carbonate is added dropwise to control the pH at 6.7-6.8; and fermentation is carried out for 20-30 hours, maintaining a constant temperature of 30°C. In a preferred embodiment, the sorbitol concentration in the sorbitol solution is 600 mg / L. In a preferred embodiment, the mass ratio of Pantoea ananatis to Gluconobacter oxydans is 2-4:1. In a preferred embodiment, the fermentation medium is formulated as follows: 20-25 g / L sorbitol, 2-3 g / L yeast extract, 10-15 g / L corn steep liquor, 4-7 g / L urea, 0.6-1 g / L magnesium sulfate, and 8-15 g / L calcium carbonate, prepared in water.

[0031] The Gluconobacter oxydans used in the following examples of the present invention are all from GOYJ11991 of Shanghai Guyan Industrial Co., Ltd.

[0032] The Pantoea ananatis used in the following examples of the present invention is GOYJ11952 from Shanghai Guyan Industrial Co., Ltd.

[0033] Example 1

[0034] Preparation of 2-keto-L-gulonic acid:

[0035] 15 L of fermentation medium was added to a 50 L fermentation tank. The fermentation medium formula was as follows: 20 g / L sorbitol, 2 g / L yeast extract, 12 g / L corn steep liquor, 4 g / L urea, 0.6 g / L magnesium sulfate, and 8 g / L calcium carbonate, prepared with water.

[0036] The mixed seed liquid of Pantoea ananatis and Gluconobacter oxydans was inoculated at an inoculum volume of 12% (mass ratio), and the inoculation ratio was 3:1.

[0037] Add sorbitol solution dropwise, the sorbitol concentration in the sorbitol solution is 600 mg / L, and the sorbitol concentration in the fermentation tank is controlled between 15-20 g / L;

[0038] At the same time, sodium carbonate was added using an automatic pH control system to control the pH at 6.7-6.8;

[0039] Ferment for 20-30 hours, maintaining a constant temperature of 30°C.

[0040] After detection and calculation, the molar conversion rate of 2-keto-L-gulonic acid was 92.3%.

[0041] Preparation of Vitamin C:

[0042] Dissolve 370g of 2-keto-L-gulonic acid in 8L of water.

[0043] Add 10g citric acid, 0.5g palladium acetate and 5g L-alanine to the solution and react at 30-35 degrees Celsius for 1-2 hours. The mass ratio of palladium acetate, citric acid and L-alanine is 1:(15-30):(5-20)

[0044] Then the mixture is heated to 50-55°C and the reaction is carried out for 20 hours. The heating is then stopped and the material is discharged to obtain a solid liquid containing vitamin C.

[0045] Cool the crystallization at room temperature for 4-6 hours, and then use centrifugation or membrane filtration to separate the crude vitamin C crystals and the filtrate.

[0046] After testing and calculation, the conversion rate of the obtained vitamin C was 94.3%.

[0047] Example 2

[0048] Preparation of 2-keto-L-gulonic acid:

[0049] 15 L of fermentation medium was added to a 50 L fermentation tank. The fermentation medium formula was as follows: 25 g / L sorbitol, 3 g / L yeast extract, 10 g / L corn steep liquor, 6 g / L urea, 0.8 g / L magnesium sulfate, and 10 g / L calcium carbonate, prepared with water.

[0050] The mixed seed liquid of Pantoea ananatis and Gluconobacter oxydans was inoculated at an inoculum volume of 12% (mass ratio), and the inoculation ratio was 3:1.

[0051] Add sorbitol solution dropwise, the sorbitol concentration in the sorbitol solution is 400 mg / L, and the sorbitol concentration in the fermentation tank is controlled between 15-20 g / L;

[0052] At the same time, sodium carbonate was added using an automatic pH control system to control the pH at 6.7-6.8;

[0053] Ferment for 20-30 hours, maintaining a constant temperature of 30°C.

[0054] After detection and calculation, the molar conversion rate of 2-keto-L-gulonic acid was 92.1%.

[0055] Preparation of Vitamin C:

[0056] Dissolve 350g of 2-keto-L-gulonic acid in 8L of water.

[0057] 12 g of citric acid, 0.7 g of palladium acetate and 7 g of L-alanine were added to the solution and reacted at 30-35 degrees Celsius for 1-2 hours.

[0058] Then the mixture is heated to 50-55°C and the reaction is carried out for 20 hours. The heating is then stopped and the material is discharged to obtain a solid liquid containing vitamin C.

[0059] Cool the crystallization at room temperature for 4-6 hours, and then use centrifugation or membrane filtration to separate the crude vitamin C crystals and the filtrate.

[0060] After testing and calculation, the conversion rate of the obtained vitamin C was 94.7%.

[0061] Example 3

[0062] Preparation of 2-keto-L-gulonic acid:

[0063] 15 L of fermentation medium was added to a 50 L fermentation tank. The fermentation medium formula was as follows: 25 g / L sorbitol, 3 g / L yeast extract, 10 g / L corn steep liquor, 6 g / L urea, 0.8 g / L magnesium sulfate, and 10 g / L calcium carbonate, prepared with water.

[0064] The mixed seed liquid of Gluconobacter oxidans was inoculated at an inoculum volume of 12% (mass ratio), with an inoculation ratio of 3:1.

[0065] Add sorbitol solution dropwise, the sorbitol concentration in the sorbitol solution is 400 mg / L, and the sorbitol concentration in the fermentation tank is controlled between 15-20 g / L;

[0066] At the same time, sodium carbonate was added using an automatic pH control system to control the pH at 6.7-6.8;

[0067] Ferment for 20-30 hours, maintaining a constant temperature of 30°C.

[0068] After detection and calculation, the molar conversion rate of 2-keto-L-gulonic acid was 88.1%.

[0069] Example 4

[0070] Preparation of 2-keto-L-gulonic acid:

[0071] 15 L of fermentation medium was added to a 50 L fermentation tank. The fermentation medium formula was as follows: 25 g / L sorbitol, 3 g / L yeast extract, 10 g / L corn steep liquor, 6 g / L urea, 0.8 g / L magnesium sulfate, and 10 g / L calcium carbonate, prepared with water.

[0072] Pantoea ananatis was inoculated at an inoculum rate of 12% (mass ratio).

[0073] Add sorbitol solution dropwise, the sorbitol concentration in the sorbitol solution is 400 mg / L, and the sorbitol concentration in the fermentation tank is controlled between 15-20 g / L;

[0074] At the same time, sodium carbonate was added using an automatic pH control system to control the pH at 6.7-6.8;

[0075] Ferment for 20-30 hours, maintaining a constant temperature of 30°C.

[0076] After detection and calculation, the molar conversion rate of 2-keto-L-gulonic acid was 89.5%.

[0077] Example 5

[0078] Preparation of Vitamin C:

[0079] Dissolve 350g of 2-keto-L-gulonic acid in 8L of water.

[0080] 12 g of citric acid and 0.7 g of palladium acetate were added to the solution and reacted at 30-35 degrees Celsius for 1-2 hours.

[0081] Then the mixture is heated to 50-55°C and the reaction is carried out for 20 hours. The heating is then stopped and the material is discharged to obtain a solid liquid containing vitamin C.

[0082] Cool the crystallization at room temperature for 4-6 hours, and then use centrifugation or membrane filtration to separate the crude vitamin C crystals and the filtrate.

[0083] After testing and calculation, the conversion rate of the obtained vitamin C was 90.3%.

[0084] Example 6

[0085] Preparation of Vitamin C:

[0086] Dissolve 350g of 2-keto-L-gulonic acid in 8L of water.

[0087] 0.7 g of palladium acetate and 7 g of L-alanine were added to the solution and reacted at 30-35 degrees Celsius for 1-2 hours.

[0088] Then the mixture is heated to 50-55°C and the reaction is carried out for 20 hours. The heating is then stopped and the material is discharged to obtain a solid liquid containing vitamin C.

[0089] Cool the crystallization at room temperature for 4-6 hours, and then use centrifugation or membrane filtration to separate the crude vitamin C crystals and the filtrate.

[0090] After testing and calculation, the conversion rate of the obtained vitamin C was 88.9%.

[0091] The above examples show that the use of Pantoea ananatis and Gluconobacter oxydans has a higher conversion rate, and the use of palladium acetate, citric acid and L-alanine also has a good synergistic effect, which can greatly improve the conversion rate of the reaction.

[0092] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, from all points of view, the embodiments should be regarded as illustrative and non-restrictive. The scope of the present invention is defined by the appended claims rather than the foregoing description, and it is intended that all changes that come within the meaning and range of equivalents of the claims be included within the present invention.

[0093] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A method for preparing vitamin C, characterized in that, The following steps are involved: dissolving 2-keto-L-gulonic acid in water to obtain a ketogulonic acid solution; Adding a catalyst consisting of palladium acetate, citric acid, and L-alanine to the ketogulonic acid solution and reacting at 30-35 degrees Celsius for 1-2 hours; Heat to 50-55°C, react for 20 hours, stop heating and discharge the material to obtain a solid liquid containing vitamin C; The solid-liquid containing vitamin C is cooled and crystallized at room temperature for 4-6 hours, and then centrifuged and purified to obtain vitamin C; The mass ratio of palladium acetate, citric acid and L-alanine is 1:(15-30):(5-20).

2. A method for preparing vitamin C according to claim 1, characterized in that, The content of 2-keto-L-gulonic acid in the ketogulonic acid solution is 300-500 g / L.

3. A method for preparing vitamin C according to claim 1, characterized in that, The dosage of the catalyst is 1.5-3 g / L.

4. A method for preparing vitamin C according to claim 1, characterized in that, The preparation steps of the 2-keto-L-gulonic acid include: Add fermentation medium to the fermentation tank; The inoculum was inoculated with a mixed seed solution of Pantoea ananatis and Gluconobacter oxydans; Add sorbitol solution dropwise to control the sorbitol concentration in the fermenter between 15-20 g / L; Add sodium carbonate dropwise to control the pH at 6.7-6.8; Ferment for 20-30 hours, maintaining a constant temperature of 30°C.

5. A method for preparing vitamin C according to claim 4, characterized in that, The concentration of sorbitol in the sorbitol solution is 600 mg / L.

6. A method for preparing vitamin C according to claim 4, characterized in that, The mass ratio of Pantoea ananatis to Gluconobacter oxydans is 2-4:

1.

7. A method for preparing vitamin C according to claim 4, characterized in that, The fermentation medium comprises 20-25 g / L of sorbitol, 2-3 g / L of yeast extract, 10-15 g / L of corn steep liquor, 4-7 g / L of urea, 0.6-1 g / L of magnesium sulfate, and 8-15 g / L of calcium carbonate, and is prepared with water.