A method for separating arginine mother liquor to prepare ornithine hydrochloride

Abstract

The present invention relates to the field of biochemical engineering technology and provides a method for preparing ornithine hydrochloride by separating arginine mother liquor. The present invention separates the arginine mother liquor with an ion exchange resin, concentrates the obtained ornithine effluent, and then adjusts the pH value with hydrochloric acid to obtain an ornithine hydrochloride concentrate, and then obtains high-purity ornithine hydrochloride through a first decolorization, a first concentration crystallization, a second decolorization, and a second concentration crystallization. The method provided by the present invention is simple to operate and low in cost, and the purity of the obtained ornithine hydrochloride is greater than 99%. The present invention fully utilizes the mother liquor in the arginine production process, does not require additional large amounts of raw material input, and consumes less energy and reagents, significantly reducing the production cost of ornithine hydrochloride, improving production efficiency, reducing waste emissions, being more environmentally friendly, and meeting the requirements of sustainable development.

Description

Technical Field

[0001] The present invention relates to the technical field of biochemical engineering, in particular to a method for preparing ornithine hydrochloride by separating arginine mother liquor. Background Art

[0002] Arginine, an amino acid involved in a variety of key physiological processes in organisms, is widely used in the food, pharmaceutical, and health care industries. Currently, the common method for producing arginine is fermentation with Corynebacterium glutamicum.

[0003] During the arginine production process using Corynebacterium glutamicum fermentation, ornithine is produced. During the separation and purification of arginine, an arginine mother liquor is produced. With increasing separation and purification cycles, ornithine gradually accumulates in the arginine mother liquor. Ornithine also has significant physiological functions and application value. In medicine, it is often used to treat hyperammonemia caused by acute and chronic liver disease and has a positive effect on improving liver function. In the health supplement field, it can promote growth hormone secretion and effectively relieve sports fatigue, making it a popular choice among fitness enthusiasts and athletes. However, arginine and ornithine have similar structures, and the arginine mother liquor has a high viscosity, making separation difficult. This results in low economic efficiency of the arginine mother liquor, which usually has to be sold externally, resulting in a waste of resources.

[0004] Currently, methods for efficiently separating ornithine from arginine mother liquor include chromatography and membrane separation. However, the purity of the products obtained by these methods is not high (usually less than 99%), which affects their application in high-end fields. In addition, the separation cost is high, making them unsuitable for large-scale production. Summary of the Invention

[0005] In view of this, the present invention provides a method for preparing ornithine hydrochloride by separating arginine mother liquor. The method provided by the present invention is simple to operate, has low production cost, and the obtained ornithine hydrochloride has high purity.

[0006] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0007] A method for preparing ornithine hydrochloride by separating arginine mother liquor, characterized in that it comprises the following steps:

[0008] The arginine mother liquor is separated by ion exchange resin to obtain an ornithine effluent; the ion exchange resin is WA-2 resin; the flow rate of the arginine mother liquor is 2-4 BV / h;

[0009] The ornithine effluent is concentrated, and then the pH value is adjusted to 4.8-5 with hydrochloric acid to obtain an ornithine hydrochloride concentrate; the vacuum degree of the concentration is -0.085-0.1 MPa, and the end point refractive index is 55-60%;

[0010] The ornithine hydrochloride concentrate and activated carbon are mixed for a first decolorization to obtain a first decolorized solution; the mass of the activated carbon used for the first decolorization is greater than or equal to 5% of the mass of the ornithine hydrochloride concentrate; the temperature for the first decolorization is 55-60° C.;

[0011] The first decolorized solution is subjected to a first concentrated crystallization to obtain a crude product of ornithine hydrochloride; the vacuum degree of the first concentrated crystallization is -0.085 to -0.1 MPa, and the end point solid content is 75 to 80 wt%;

[0012] The crude ornithine hydrochloride, water and activated carbon are mixed for a second decolorization to obtain a second decolorized solution; the temperature of the second decolorization is 55-60° C.;

[0013] The second decolorized liquid is subjected to a second concentrated crystallization to obtain ornithine hydrochloride; the vacuum degree of the second concentrated crystallization is -0.085~-0.1MPa, and the end point solid content is 60~65wt%.

[0014] Preferably, before the ion exchange resin separation, the arginine mother liquor is further subjected to solid-liquid separation.

[0015] Preferably, the concentration temperature is 60-80°C.

[0016] Preferably, the amount of activated carbon used for the first decolorization is 5-8% of the mass of the ornithine hydrochloride concentrate; and the time for the first decolorization is 40-60 minutes.

[0017] Preferably, the temperature of the first concentrated crystallization is 55-65°C.

[0018] Preferably, the amount of activated carbon used for the second decolorization is 3-5% of the quality of the crude ornithine hydrochloride.

[0019] Preferably, the mass ratio of the crude ornithine hydrochloride to water is (1-2):5; and the second decolorization time is 40-60 min.

[0020] Preferably, the temperature of the second concentrated crystallization is 60-70°C.

[0021] Preferably, the concentration of ornithine in the arginine mother solution is 3-5 wt %.

[0022] Preferably, the purity of the ornithine hydrochloride is above 99%.

[0023] The invention provides a method for preparing ornithine hydrochloride by separating an arginine mother liquor. The method comprises the following steps: subjecting the arginine mother liquor to ion exchange resin separation to obtain an ornithine effluent, wherein the ion exchange resin is WA-2 resin; the flow rate of the arginine mother liquor is 2-4 BV / h; concentrating the ornithine effluent and then adjusting the pH value to 4.8-5 with hydrochloric acid to obtain an ornithine hydrochloride concentrated solution; the vacuum degree of the concentration is -0.085--0.1 MPa, and the end point refractive index is 55-60%; mixing the ornithine hydrochloride concentrated solution with activated carbon for a first decolorization to obtain a first decolorized solution, wherein the mass of the activated carbon used for the first decolorization is greater than or equal to 5% of the mass of the ornithine hydrochloride concentrated solution. The first decolorization temperature is 55-60°C; the first decolorized solution is subjected to a first concentration and crystallization to obtain a crude ornithine hydrochloride product; the vacuum degree of the first concentration and crystallization is -0.085 to -0.1 MPa, and the end-point solid content is 75-80 wt %. The crude ornithine hydrochloride product, water, and activated carbon are mixed for a second decolorization to obtain a second decolorized solution; the second decolorization temperature is 55-60°C; the second decolorized solution is subjected to a second concentration and crystallization to obtain ornithine hydrochloride; the vacuum degree of the second concentration and crystallization is -0.085 to -0.1 MPa, and the end-point solid content is 60-65 wt %. The present invention uses WA-2 resin to separate ornithine from arginine mother liquor, greatly improving the ornithine recovery rate and reducing resource waste. Furthermore, by strictly controlling the conditions of the concentration and decolorization steps, the present invention can effectively remove impurities and obtain a high-purity ornithine hydrochloride product. The present invention makes full use of the mother liquor in the arginine production process, does not require additional large amounts of raw material input, has low energy consumption and reagent consumption, significantly reduces the production cost of ornithine hydrochloride, improves production efficiency, and simultaneously reduces waste emissions, is more environmentally friendly, and meets the requirements of sustainable development. DETAILED DESCRIPTION

[0024] The present invention provides a method for preparing ornithine hydrochloride by separating arginine mother liquor, comprising the following steps:

[0025] The arginine mother liquor is separated by ion exchange resin to obtain an ornithine effluent; the ion exchange resin is WA-2 resin; the flow rate of the arginine mother liquor is 2-4 BV / h;

[0026] The ornithine effluent is concentrated, and then the pH value is adjusted to 4.8-5 with hydrochloric acid to obtain an ornithine hydrochloride concentrate; the vacuum degree of the concentration is -0.085-0.1 MPa, and the end point refractive index is 55-60%;

[0027] The ornithine hydrochloride concentrate is mixed with activated carbon for a first decolorization to obtain a first decolorized solution; the mass of the activated carbon used for the first decolorization is greater than or equal to 5% of the mass of the ornithine hydrochloride concentrate. The temperature for the first decolorization is 55-60°C;

[0028] The first decolorized solution is subjected to a first concentrated crystallization to obtain a crude product of ornithine hydrochloride; the vacuum degree of the first concentrated crystallization is -0.085 to -0.1 MPa, and the end point solid content is 75 to 80 wt%;

[0029] The crude ornithine hydrochloride, water and activated carbon are mixed for a second decolorization to obtain a second decolorized solution; the temperature of the second decolorization is 55-60° C.;

[0030] The second decolorized liquid is subjected to a second concentrated crystallization to obtain ornithine hydrochloride; the vacuum degree of the second concentrated crystallization is -0.085~-0.1MPa, and the end point solid content is 60~65wt%.

[0031] The present invention subjects an arginine mother liquor to ion exchange resin separation to obtain an ornithine effluent. In the present invention, the arginine mother liquor is specifically a tertiary arginine mother liquor, i.e., the mother liquor remaining after three separations and purifications of a fermentation broth obtained by a Corynebacterium glutamicum fermentation method; the ornithine content in the arginine mother liquor is 3 to 5 wt %. Prior to ion exchange resin separation, the present invention preferably subjects the arginine mother liquor to solid-liquid separation, preferably by filtration, to remove insoluble impurities therein to obtain a clarified arginine mother liquor.

[0032] In the present invention, the ion exchange resin is WA-2 resin; the present invention has no particular requirements for the source of the WA-2 resin, and a commercially available product can be used; during the ion exchange resin separation, the flow rate of the arginine mother liquor is 2 to 4 BV / h, specifically 2 BV / h, 2.5 BV / h, 3 BV / h, or 4 BV / h; the present invention has no particular requirements for the apparatus used for the ion exchange resin separation, and any apparatus known to those skilled in the art can be used, such as a moving bed, simulated moving bed, or fluidized bed, or directly using a resin column for separation. In a specific embodiment of the present invention, the arginine mother liquor is preferably passed through a resin column loaded with WA-2 resin, and the resulting effluent is collected as the ornithine effluent.

[0033] After obtaining the ornithine effluent, the present invention concentrates the ornithine effluent and then adjusts the pH to 4.8-5 with hydrochloric acid to obtain an ornithine hydrochloride concentrate. In the present invention, the concentration temperature is preferably 60-80°C, specifically 60°C, 65°C, 70°C, 75°C, or 80°C; the concentration vacuum is -0.085-0.1 MPa, specifically -0.085 MPa, -0.09 MPa, -0.095 MPa, or -0.1 MPa; the concentration endpoint refractive index is 55-60%, specifically 55%, 56%, 57%, 58%, or 60%; and the concentration is preferably performed on a rotary evaporator. By controlling the concentration endpoint refractive index, the present invention can reduce the volume of ornithine material, which is beneficial for improving the efficiency of the subsequent carbon decolorization process.

[0034] In the present invention, the hydrochloric acid is preferably concentrated hydrochloric acid (concentration of 36-38 wt%). Ornithine is not easy to crystallize. In the present invention, ornithine is converted into ornithine hydrochloride by adding hydrochloric acid, and then subsequent purification is performed, which is conducive to achieving efficient recovery of ornithine.

[0035] After obtaining the ornithine hydrochloride concentrate, the present invention mixes the ornithine hydrochloride concentrate with activated carbon for a first decolorization to obtain a first decolorized solution. In the present invention, the amount of activated carbon used for the first decolorization is preferably greater than or equal to 5% of the mass of the ornithine hydrochloride concentrate, more preferably 5-8% of the mass of the ornithine hydrochloride concentrate, specifically 5%, 6%, 7%, or 8%. The activated carbon used for the first decolorization is preferably Yuanli 303-05 activated carbon. The temperature for the first decolorization is 55-60°C, and the time is preferably 40-60 minutes, specifically 40 minutes, 45 minutes, 50 minutes, 55 minutes, or 60 minutes. After the first decolorization is completed, the activated carbon is removed to obtain the first decolorized solution.

[0036] After obtaining the first decolorized solution, the present invention performs a first concentrated crystallization on the first decolorized solution to obtain a crude ornithine hydrochloride product. In the present invention, the temperature of the first concentrated crystallization is preferably 55 to 65°C, specifically 55°C, 58°C, 60°C, or 65°C; the vacuum degree of the first concentrated crystallization is -0.085 to -0.1 MPa, specifically -0.085 MPa, -0.09 MPa, -0.095 MPa, or -0.1 MPa; the endpoint solid content of the first concentrated crystallization is 75 to 80 wt%, specifically 75 wt%, 76 wt%, 77 wt%, 78 wt%, or 80 wt%; the first concentrated crystallization is preferably performed in a rotary evaporator; the present invention controls the conditions of the first concentrated crystallization within the above range, which can fully remove impurities and improve product purity.

[0037] After the first concentration and crystallization is completed, the present invention preferably washes the obtained concentrate with deionized water to obtain crude ornithine hydrochloride.

[0038] After obtaining crude ornithine hydrochloride, the present invention combines the crude ornithine hydrochloride with water and activated carbon for a second decolorization step to produce a second decolorized solution. In the present invention, the amount of activated carbon used for the second decolorization step is 3-5% of the crude ornithine hydrochloride mass, specifically 3%, 3.5%, 4%, 4.5%, or 5%. The type of activated carbon used for the second decolorization step is the same as that used for the first decolorization step and is not further described here. The mass ratio of the crude ornithine hydrochloride to water is preferably (1-2):5. The second decolorization step is performed at a temperature of 55-60°C and for a time of 40-60 minutes, specifically 40 minutes, 45 minutes, 50 minutes, 55 minutes, or 60 minutes. After the second decolorization step is completed, the activated carbon is removed to produce a second decolorized solution.

[0039] After obtaining the second decolorized solution, the present invention performs a second concentrated crystallization on the second decolorized solution to obtain ornithine hydrochloride. In the present invention, the temperature of the second concentrated crystallization is preferably 60 to 70°C, specifically 60°C, 65°C or 70°C, the vacuum degree of the second concentrated crystallization is -0.085 to -0.1MPa, specifically -0.085MPa, -0.09MPa, -0.095MPa or -0.1MPa; the endpoint solid content of the second concentrated crystallization is 60 to 65wt%, specifically 60wt%, 62wt%, 63wt%, 64wt% or 65wt%; the present invention controls the endpoint solid content of the second concentrated crystallization within the above range, which can fully remove impurities and improve product purity.

[0040] After the second concentrated crystallization is completed, the present invention preferably washes the obtained crystals with deionized water to obtain a finished product of ornithine hydrochloride. In the present invention, the purity of the ornithine hydrochloride is greater than 99%, preferably greater than 99.3%.

[0041] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0042] The arginine mother liquors used in the following examples were all tertiary mother liquors, with an ornithine content of 4.2 wt %. The tertiary mother liquors were filtered to remove insoluble impurities, and the resulting clarified arginine mother liquors were used in subsequent examples.

[0043] The activated carbon used in the first decolorization and the second decolorization in the following examples is commercially available Yuanli 303-05 activated carbon.

[0044] Example 1

[0045] 5000 mL of arginine mother liquor was passed through a resin column packed with WA-2 resin at a rate of 2 BV / h to obtain an ornithine effluent. The ornithine effluent was placed in a rotary evaporator, and the concentration temperature and vacuum in the concentrator were controlled at 70°C and -0.1 MPa, and concentrated to a refractive index of 55%. Concentrated hydrochloric acid was added to the concentrated solution to adjust the pH to 5.0, yielding an ornithine hydrochloride concentrate. Activated carbon was then added for a first decolorization step, with the mass of the activated carbon being 5% of the mass of the ornithine hydrochloride concentrate. The decolorization temperature was 60°C, and the decolorization time was 40 minutes. After decolorization, the activated carbon was removed to obtain a first decolorized solution. The first decolorized solution was then subjected to a first concentration and crystallization step, controlled at 55°C and a vacuum of -0.1 MPa, to an end-point solids content of 75 wt%. After the concentration and crystallization step, the crystals were washed with deionized water to obtain crude ornithine hydrochloride. Crude ornithine hydrochloride and water were mixed in a weight ratio of 2:5, and then activated carbon containing 5% by weight of the crude ornithine hydrochloride was added for a second decolorization step at 60°C for 40 minutes. After decolorization, the activated carbon was removed to obtain a second decolorized solution. The collected second decolorized solution was subjected to a second concentration crystallization step at a controlled concentration temperature of 60°C, a vacuum degree of -0.1 MPa, and an endpoint solids content of 65 wt%. After the concentration crystallization step, the crystals were washed with deionized water to obtain a finished ornithine hydrochloride product. Liquid chromatography analysis revealed a purity of 99.35% and a recovery rate of 79.4%.

[0046] Example 2

[0047] 5000 mL of arginine mother liquor was passed through a resin column packed with WA-2 resin at a rate of 4 BV / h to obtain an ornithine effluent. The ornithine effluent was placed in a rotary evaporator and concentrated to a refractive index of 60%. Concentrated hydrochloric acid was added to the concentrated solution to adjust the pH to 5.0, yielding an ornithine hydrochloride concentrate. Activated carbon was added for a first decolorization step, with the weight of the activated carbon being 8% of the ornithine hydrochloride concentrate. The decolorization temperature was controlled at 60°C for 60 minutes. After decolorization, the activated carbon was removed to obtain a first decolorized solution. The collected first decolorized solution was then subjected to a first concentration crystallization step, with the temperature controlled at 65°C and the vacuum at -0.085 MPa to an end-point solids content of 80 wt%. After concentration, the crystals were washed with deionized water to yield crude ornithine hydrochloride. The crude ornithine hydrochloride and water were mixed in a weight ratio of 1.5:5, and then 8% by mass of activated carbon was added for a second decolorization process at 60°C for 60 minutes. After decolorization, the activated carbon was removed to obtain a second decolorized solution. The collected second decolorized solution was subjected to a second concentration crystallization process at a controlled concentration temperature of 60°C and a vacuum degree of -0.085 MPa, with an endpoint solid content of 60 wt%. After concentration, the crystals were washed with deionized water to obtain the finished ornithine hydrochloride. Liquid chromatography analysis revealed a purity of 99.60% and a recovery rate of 78.0%.

[0048] Example 3

[0049] 5000 mL of arginine mother liquor was passed through a resin column packed with WA-2 resin at a rate of 3 BV / h to obtain an ornithine effluent. The ornithine effluent was placed on a rotary evaporator, concentrated at a temperature of 60°C and a vacuum of -0.095 MPa, and concentrated to a refractive index of 58%. Concentrated hydrochloric acid was added to the concentrated solution to adjust the pH to 5.0, yielding an ornithine hydrochloride concentrate. Activated carbon was then added for a first decolorization step, with the weight of the activated carbon being 6% of the ornithine hydrochloride concentrate. The decolorization temperature was controlled at 60°C for 50 minutes. After decolorization, the activated carbon was removed to obtain a first decolorized solution. The collected first decolorized solution was subjected to a first concentration crystallization step, with the temperature controlled at 60°C and a vacuum of -0.095 MPa. The final solids content was 78 wt%. After concentration, the crystals were washed with deionized water to yield crude ornithine hydrochloride. The crude ornithine hydrochloride and water were mixed in a weight ratio of 2:5, and then 4% by weight of activated carbon was added for a second decolorization process at 60°C for 50 minutes. After decolorization, the activated carbon was removed to obtain a second decolorized solution. The collected second decolorized solution was concentrated under reduced pressure at a temperature of 65°C and a vacuum degree of -0.095 MPa to an endpoint solids content of 63 wt%. After concentration, the crystals were washed with deionized water to obtain the finished ornithine hydrochloride. Liquid chromatography analysis showed a purity of 99.45% and a recovery of 80.3%.

[0050] Example 4

[0051] 5000 mL of arginine mother liquor was passed through a resin column packed with WA-2 resin at a rate of 2.5 BV / h to obtain an ornithine effluent. The ornithine effluent was placed on a rotary evaporator, concentrated at a temperature of 80°C and a vacuum of -0.1 MPa, and concentrated to a refractive index of 56%. Concentrated hydrochloric acid was added to the concentrated solution to adjust the pH to 5.0, yielding an ornithine hydrochloride concentrate. Activated carbon was added for decolorization, with the mass of the activated carbon accounting for 7% of the mass of the ornithine hydrochloride concentrate. The decolorization temperature was controlled at 60°C for 55 minutes. After decolorization, the activated carbon was removed to obtain a first decolorized solution. The collected first decolorized solution was subjected to a first concentrated crystallization process at a temperature of 62°C and a vacuum of -0.1 MPa, with an end-point solids content of 76 wt%. After concentration, the crystals were washed with deionized water to yield crude ornithine hydrochloride. The crude ornithine hydrochloride and water were mixed in a weight ratio of 1:5, and then 4.5% by weight of activated carbon was added for a second decolorization process at 60°C for 50 minutes. After decolorization, the activated carbon was removed to obtain a second decolorized solution. The collected second decolorized solution was subjected to a second concentration crystallization process at a controlled concentration temperature of 68°C and a vacuum degree of -0.1 MPa, with an endpoint solid content of 62 wt%. After concentration, the crystals were washed with deionized water to obtain the finished ornithine hydrochloride. Liquid chromatography analysis revealed a purity of 99.50% and a recovery rate of 77.5%.

[0052] Example 5

[0053] 5000 mL of arginine mother liquor was passed through a resin column packed with WA-2 resin at a rate of 3 BV / h to obtain an ornithine effluent. The ornithine effluent was placed on a rotary evaporator, concentrated at a temperature of 75°C and a vacuum of -0.09 MPa, and concentrated to a refractive index of 57%. Concentrated hydrochloric acid was added to the concentrated solution to adjust the pH to 4.8 to obtain an ornithine hydrochloride concentrate. Activated carbon was added for decolorization, with the mass of the activated carbon being 5% of the mass of the ornithine hydrochloride concentrate. The decolorization temperature was controlled at 60°C for 45 minutes. After decolorization, the activated carbon was removed to obtain a first decolorized solution. The collected first decolorized solution was subjected to a first concentration crystallization process, with the concentration temperature controlled at 58°C and a vacuum of -0.09 MPa to an end-point solids content of 77 wt%. After concentration, the crystals were washed with deionized water to obtain crude ornithine hydrochloride. The crude ornithine hydrochloride and water were mixed in a weight ratio of 1.5:5, and then 5% by weight of activated carbon was added for a second decolorization process at 60°C for 45 minutes. After decolorization, the activated carbon was removed to obtain a second decolorized solution. The collected second decolorized solution was subjected to a second concentration crystallization process at a controlled concentration temperature of 63°C and a vacuum degree of -0.09 MPa, with an endpoint solid content of 64 wt%. After concentration, the crystals were washed with deionized water to obtain the finished ornithine hydrochloride. Liquid chromatography analysis revealed a purity of 99.40% and a recovery rate of 80.8%.

[0054] Comparative Example 1

[0055] The other conditions were controlled to be the same as those in Example 1, except that the solid content at the end of the second concentrated crystallization was controlled to 70%. The purity of the final ornithine hydrochloride product obtained was 97.82%, and the recovery rate was 80.2%.

[0056] Comparative Example 2

[0057] The other conditions were controlled to be the same as those in Example 2, except that the solid content at the end of the first concentrated crystallization was controlled to 85%. The purity of the final ornithine hydrochloride product obtained was 98.20%, the recovery rate was 78.5%, and the centrifugation was difficult due to the high viscosity of the material.

[0058] Comparative Example 3

[0059] Other conditions were controlled to be the same as in Example 3. Only during the first decolorization, the amount of activated carbon was reduced to 3% of the mass of the ornithine hydrochloride concentrate. The purity of the final ornithine hydrochloride product obtained was 98.5%, the recovery rate was 81.5%, and the impurity content was significantly increased, affecting the product quality.

[0060] Comparative Example 4

[0061] Other conditions were controlled to be the same as those in Example 3. Only in the ion resin exchange separation, the flow rate of the arginine mother liquor was increased to 4.0 BV / h. The purity of the final ornithine hydrochloride product was reduced by 20%, and the recovery rate was 75.5%, indicating that a too fast flow rate would affect the separation effect.

[0062] Comparative Example 5

[0063] All other conditions were the same as in Example 1, except that the WA-2 resin was replaced with the JK-008 resin. Liquid chromatography analysis of the resulting ornithine hydrochloride product revealed a purity of 92.5% and a recovery of 70.4%, significantly lower than the results obtained in the example using the WA-2 resin, indicating that the type of resin significantly influences the separation effect.

[0064] Comparative Example 6

[0065] All other conditions were the same as in Example 2, except that the vacuum level was adjusted to -0.05 MPa during the ornithine effluent concentration, first concentration crystallization, and second concentration crystallization steps. The resulting ornithine hydrochloride product had a purity of 98.8% and a recovery rate of 80.6%. The concentration efficiency decreased due to the change in vacuum level.

[0066] Comparative Example 7

[0067] Other conditions were the same as in Example 3, except that the decolorization temperature was increased to 70°C in the first and second decolorization steps. The purity of the resulting ornithine hydrochloride product was 95.4%, and the recovery rate was 76.6%. Due to the high decolorization temperature, the decolorization effect of the activated carbon was reduced, and the impurity content of the finished product increased, indicating that too high a decolorization temperature is not conducive to impurity removal.

[0068] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing ornithine hydrochloride by separating arginine mother liquor, characterized in that: The following steps are involved: The arginine mother liquor is separated by ion exchange resin to obtain an ornithine effluent; the ion exchange resin is WA-2 resin; the flow rate of the arginine mother liquor is 2-4 BV / h; The ornithine effluent is concentrated, and then the pH value is adjusted to 4.8-5 with hydrochloric acid to obtain an ornithine hydrochloride concentrate; the vacuum degree of the concentration is -0.085-0.1 MPa, and the end point refractive index is 55-60%; mixing the ornithine hydrochloride concentrate with activated carbon for a first decolorization to obtain a first decolorized solution; The mass of the activated carbon used in the first decolorization is greater than or equal to 5% of the mass of the ornithine hydrochloride concentrate; the temperature of the first decolorization is 55-60°C; The first decolorized solution is subjected to a first concentrated crystallization to obtain a crude product of ornithine hydrochloride; the vacuum degree of the first concentrated crystallization is -0.085 to -0.1 MPa, and the end point solid content is 75 to 80 wt%; the temperature of the first concentrated crystallization is 55 to 65° C.; The crude ornithine hydrochloride, water and activated carbon are mixed for a second decolorization to obtain a second decolorized solution; the temperature of the second decolorization is 55-60° C.; The second decolorized solution is subjected to a second concentrated crystallization to obtain ornithine hydrochloride; the vacuum degree of the second concentrated crystallization is -0.085 to -0.1 MPa, the end point solid content is 60 to 65 wt%; the temperature of the second concentrated crystallization is 60 to 70°C; The concentration of ornithine in the arginine mother liquor is 3-5wt%; the arginine mother liquor is the mother liquor remaining after three separation and purification of the fermentation liquid obtained when arginine is produced by Corynebacterium glutamicum fermentation.

2. The method according to claim 1, characterized in that Before the ion exchange resin separation, the arginine mother liquor is subjected to solid-liquid separation.

3. The method according to claim 1, characterized in that The concentration temperature is 60-80°C.

4. The method according to claim 1, wherein The amount of activated carbon used for the first decolorization is 5-8% of the mass of the ornithine hydrochloride concentrated solution; and the time for the first decolorization is 40-60 minutes.

5. The method according to claim 1, wherein The amount of activated carbon used for the second decolorization is 3-5% of the quality of the crude ornithine hydrochloride.

6. The method according to claim 1 or 5, characterized in that The mass ratio of the crude ornithine hydrochloride to water is (1-2):5; and the second decolorization time is 40-60 minutes.

7. The method according to claim 1, characterized in that The purity of the ornithine hydrochloride is above 99%.