A method for co-producing magnesium α-ketoglutarate and α-ketoglutaric acid from fermentation broth
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-06-09
- Publication Date
- 2026-08-14
AI Technical Summary
该类工艺普遍存在以下不足：其一，发酵液中目标产物利用方式较为单一，不利于根据市场需求灵活调整产品结构；其二，生产过程产生的母液因杂质多，纯度低等问题，难以再次利用，如直接排放或仅作低值利用，会造成目标产物损失，影响整体收率，易造成资源浪费；其三，一些现有的离子树脂交换法分离纯化α-酮戊二酸技术，一般都需要盐酸溶液或碱性溶液进行多级梯度洗脱，生产过程废水处理压力大，效率低；其四，若分别建设游离酸和镁盐两套独立生产工艺，则会增加能耗、物耗及后处理成本，不利于工业化连续稳定生产
[0026]本发明以含α-酮戊二酸的发酵液为原料，主要采用二级离子树脂层析法进行分离纯化，先通过Mg2+型阳离子树脂层析制备α-酮戊二酸镁，减压浓缩，使α-酮戊二酸镁与α-酮戊二酸共结晶，分离α-酮戊二酸镁后，再利用强酸性H+型阳离子树脂从α-酮戊二酸镁的结晶母液中纯化α-酮戊二酸，浓缩结晶，联产α-酮戊二酸镁及α-酮戊二酸，实现α-酮戊二酸镁生产过程中的母液闭环利用，使原料资源利用最大化。该方法操作简单，成本低廉，安全环保。既弥补了现有技术的不足，同时所得产品纯度高，无有毒有害物质残留，达到食品级产品生产要求。其中：
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Abstract
Description
Technical Field
[0001] This invention relates to the field of separation and extraction technology, and in particular to a method for co-producing magnesium α-ketoglutarate and α-ketoglutarate from fermentation broth. Background Technology
[0002] Alpha-ketoglutaric acid (α-KG) is an important intermediate metabolite in the tricarboxylic acid cycle, widely involved in energy metabolism, amino acid metabolism, and nitrogen metabolism in organisms. It has high application value in the fields of food, health products, pharmaceutical intermediates, feed additives, and biochemicals. In addition to being used as a free acid product, α-ketoglutaric acid can further form corresponding organic acid salts with metal ions. Among these, magnesium α-ketoglutarate, as a compound that combines the functions of magnesium source and α-ketoglutaric acid, also shows promising application prospects in nutritional supplements, functional food ingredients, and related formulations.
[0003] Currently, after fermentation to produce α-ketoglutaric acid, the fermentation broth usually needs to be separated and purified, mainly through ion exchange resin methods and organic solvent extraction. Magnesium α-ketoglutarate (α-KG-Mg) is typically produced by neutralizing high-purity α-ketoglutaric acid with magnesium sources such as magnesium oxide, magnesium hydroxide, or magnesium carbonate. Existing processes usually employ a single-product route, either producing only free α-ketoglutaric acid or further preparing its salts from purified α-ketoglutaric acid. This type of process generally suffers from the following shortcomings: First, the utilization of the target product in the fermentation broth is relatively limited, making it difficult to flexibly adjust the product structure according to market demand. Second, the mother liquor generated during the production process is difficult to reuse due to its high impurity and low purity. Direct discharge or low-value utilization would result in the loss of the target product, affecting the overall yield and leading to resource waste. Third, some existing ion exchange resin methods for separating and purifying α-ketoglutaric acid generally require multi-stage gradient elution with hydrochloric acid or alkaline solutions, resulting in high wastewater treatment pressure and low efficiency. Fourth, constructing separate production processes for free acid and magnesium salt would increase energy consumption, material consumption, and post-treatment costs, hindering continuous and stable industrial production.
[0004] Existing technologies offer relatively few process schemes for the co-production of free α-ketoglutarate and magnesium α-ketoglutarate from the same α-ketoglutarate fermentation broth. In particular, a systematic method is lacking that simultaneously achieves high purity and yield of both products, while ensuring efficient removal of impurities from the fermentation broth, efficient distribution of the target product, effective utilization of the mother liquor, and high purity and yield of both products. Therefore, developing a co-production method that uses α-ketoglutarate fermentation broth as raw material, effectively removes impurities and purifies it, and simultaneously produces α-ketoglutarate and magnesium α-ketoglutarate, while improving the overall yield and reducing comprehensive production costs, has significant practical application value. Summary of the Invention
[0005] In view of the above, it is necessary to provide a method for co-producing magnesium α-ketoglutarate and α-ketoglutaric acid from fermentation broth. The method of the present invention can co-produce magnesium α-ketoglutarate and α-ketoglutaric acid, realize the closed-loop utilization of mother liquor in the production process of magnesium α-ketoglutarate, maximize the utilization of raw material resources, and at the same time, the obtained product has high purity and no toxic or harmful residues.
[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0007] A method for co-producing magnesium α-ketoglutarate and α-ketoglutaric acid from fermentation broth includes the following steps:
[0008] (1) Pretreatment of fermentation broth: The fermentation broth containing α-ketoglutaric acid was subjected to solid-liquid separation to obtain a clear fermentation broth;
[0009] (2) Mg 2+ Activation of the cation exchange resin column: First, Mg is activated using a soluble magnesium salt solution. 2+ The cation exchange resin column was rinsed until the pH of the effluent was the same as that of the soluble magnesium salt solution, and then the Mg solution was rinsed with purified water. 2+ The cation exchange resin column was rinsed until the pH of the effluent was neutral, thus obtaining the activated Mg. 2+ Type cation exchange resin;
[0010] (3) Mg 2+ Type II cation exchange resin column chromatography: using the activated Mg 2+ The clarified fermentation broth was subjected to chromatography using a cation exchange resin column to obtain a first chromatographic solution.
[0011] (4) First crystallization: The first chromatography solution is subjected to a first decolorization treatment and a first concentration treatment to obtain a first concentrate; the first concentrate is subjected to a first cooling crystallization and then filtered to obtain a first wet crystal and a first filtrate; the first wet crystal is washed with ethanol and then filtered to obtain a washed first wet crystal and an ethanol washing solution; the first wet crystal is dried to obtain magnesium α-ketoglutarate; the first filtrate and the ethanol washing solution are combined after ethanol recovery to obtain a processed solution;
[0012] (5) Strong acid H + Type II cation exchange resin chromatography: using strongly acidic H+ + The treatment solution was subjected to chromatography using a type cation exchange resin to obtain a second chromatographic solution.
[0013] (6) Second crystallization: The second chromatographic solution is subjected to a second decolorization treatment and a second concentration treatment to obtain a second concentrate; the second concentrate is subjected to a second cooling crystallization and then filtered to obtain a second wet crystal; the second wet crystal is dried to obtain α-ketoglutaric acid.
[0014] Furthermore, in step (1), the fermentation broth containing α-ketoglutaric acid is a fermentation broth obtained by microbial fermentation.
[0015] Further, in step (1), the solid-liquid separation is performed using an organic filter membrane, wherein the pore size of the organic filter membrane is 300 Da-1000 Da. Preferably, the pore size of the organic filter membrane is 500 Da-800 Da. More preferably, the pore size of the organic filter membrane is 500 Da.
[0016] Furthermore, in step (2), the Mg 2+ The cationic resin is a polystyrene-based resin; the soluble magnesium salt is one of magnesium chloride, magnesium nitrate, or magnesium sulfate; the amount of the soluble magnesium salt solution used is [amount missing] of the Mg [concentration missing]. 2+ The volume of the cation exchange resin column is 3-6 times that of the Mg2+ column. Preferably, the amount of the soluble magnesium salt solution used is 3-6 times the volume of the Mg2+ column. 2+ The volume of the cation exchange resin column is 4-5 times that of the Mg2+ column; more preferably, the amount of the soluble magnesium salt solution used is the same as that used for the Mg2+ column. 2+ Five times the volume of the type cation exchange resin column.
[0017] Furthermore, in step (2), the mass concentration of the soluble magnesium salt solution is 8%-10%, and the flow rate of the soluble magnesium salt solution for rinsing is 0.5 BV / h.
[0018] Furthermore, in step (3), the sample loading temperature for the chromatography is 30-35℃, and the sample loading flow rate is 0.2-0.6 BV / h, preferably 0.4 BV / h; the mass of α-ketoglutaric acid contained in the clarified fermentation broth and the mass of Mg 2+ The volume ratio of the cation exchange resin is 1:6.5-1:8.5. Preferably, the mass ratio of α-ketoglutaric acid in the clarified fermentation broth to the mass ratio of Mg is... 2+ The volume ratio of the type cation exchange resin is 1:7.0-1:7.5.
[0019] Further, in step (4), the first decolorization treatment is as follows: the first chromatography solution is decolorized with activated carbon at 50°C for 40 min to obtain the first decolorized solution, wherein the amount of activated carbon used is 0.3%-0.5% of the volume of the first chromatography solution; the first concentration treatment is as follows: the first decolorized solution is concentrated under reduced pressure at a temperature of 55-65°C and a vacuum degree of -0.1MPa to a solid content of 65%-75%, thereby obtaining the first concentrated solution.
[0020] Furthermore, in step (4), the first cooling crystallization is: the first concentrated liquid is stirred and cooled to below 10°C until a large amount of crystals precipitate out, then kept at 4-6°C and stirred for 2 hours to crystallize, and then refrigerated below 4°C for 4-6 hours.
[0021] Furthermore, in step (5), the strongly acidic H... + The cation exchange resin is a polystyrene-based resin, and the second chromatography solvent is a chromatography permeate with a pH ≤ 2.
[0022] Furthermore, in step (5), the sample loading temperature for the chromatography is 30-35℃, and the sample loading flow rate is 0.4-0.8 BV / h, preferably 0.5-0.6 BV / h; the strongly acidic H... + The volume ratio of the type cation exchange resin to the treatment solution is 1:1.5-1:2.5. Preferably, the strongly acidic H+... + The volume ratio of the cation exchange resin to the treatment solution is 1:1.5-1:1.7.
[0023] Further, in step (6), the second decolorization treatment is as follows: the second chromatography solution is decolorized with activated carbon at room temperature for 60 min to obtain the second decolorized solution, wherein the amount of activated carbon used is 0.5%-0.8% of the volume of the second chromatography solution; the second concentration treatment is as follows: the second decolorized solution is concentrated under reduced pressure at a temperature of 60-63℃ and a vacuum degree of -0.1MPa until its solid content is 60%-65%, thereby obtaining the second concentrated solution.
[0024] Furthermore, in step (6), the second cooling crystallization is: the second concentrate is stirred and cooled to 4-5℃, and kept at this temperature for 4-6 hours to crystallize.
[0025] The present invention has the following beneficial effects:
[0026] This invention uses fermentation broth containing α-ketoglutaric acid as raw material and mainly employs a two-stage ion-exchange resin chromatography method for separation and purification. First, magnesium α-ketoglutarate is prepared by Mg2+ type cation exchange resin chromatography. The mixture is then concentrated under reduced pressure to allow for co-crystallization of magnesium α-ketoglutarate and α-ketoglutaric acid. After separating the magnesium α-ketoglutarate, it is then purified using strongly acidic H₂O. + A cationic resin is used to purify α-ketoglutaric acid from the crystallization mother liquor of magnesium α-ketoglutarate, followed by concentration and crystallization to co-produce magnesium α-ketoglutarate and α-ketoglutaric acid. This achieves closed-loop utilization of the mother liquor in the magnesium α-ketoglutarate production process, maximizing the utilization of raw material resources. This method is simple to operate, low in cost, and safe and environmentally friendly. It not only overcomes the shortcomings of existing technologies but also yields products with high purity and no toxic or harmful residues, meeting the requirements for food-grade product production. Specifically:
[0027] (1) The fermentation broth of α-ketoglutarate was separated and purified using a Mg2+ type cation exchange resin. The Mg2+ type cation exchange resin adsorbs impurities in the fermentation broth and releases Mg2+. The α-ketoglutarate ions in the fermentation broth, due to their negative charge, are not adsorbed and flow out, combining with the Mg2+ released by the cation exchange resin to form magnesium α-ketoglutarate. This chromatography method removes impurities while simultaneously preparing magnesium α-ketoglutarate, and the operation is simple.
[0028] (2) After obtaining the co-crystallized magnesium α-ketoglutarate and α-ketoglutarate, the co-crystallized magnesium α-ketoglutarate was washed with anhydrous ethanol to obtain high-purity magnesium α-ketoglutarate with a purity ≥98% and a yield ≥75%. This was done by taking advantage of the fact that α-ketoglutarate is easily soluble in ethanol while magnesium α-ketoglutarate is not easily soluble.
[0029] (3) Utilizing strong acid H + The cation exchange resin is used to separate and purify the co-crystallization mother liquor and the ethanol washing liquid, removing excess salt impurities and extracting the residual α-ketoglutaric acid with a purity ≥99% and a recovery rate ≥80%. This achieves closed-loop utilization of the mother liquor in the production process of magnesium α-ketoglutaric acid, maximizing the utilization of raw material resources. Detailed Implementation
[0030] To make the technical problem to be solved, the technical solution and advantages of the present invention clearer, specific embodiments will be described below.
[0031] Please provide a detailed description.
[0032] In this invention, unless otherwise specified, all reagents and consumables used are purchased from conventional reagent manufacturers in the field; unless otherwise specified, all experimental methods and techniques used are conventional methods and techniques in the field.
[0033] This invention provides a method for co-producing magnesium α-ketoglutarate and α-ketoglutaric acid from fermentation broth, comprising the following steps:
[0034] (1) Pretreatment of fermentation broth: The fermentation broth containing α-ketoglutaric acid was subjected to solid-liquid separation to obtain a clear fermentation broth;
[0035] (2) Mg 2+ Activation of the cation exchange resin column: First, Mg is activated using a soluble magnesium salt solution. 2+ The cation exchange resin column was rinsed until the pH of the effluent was the same as that of the soluble magnesium salt solution, and then the Mg solution was rinsed with purified water. 2+ The cation exchange resin column was rinsed until the pH of the effluent was neutral, thus obtaining the activated Mg. 2+ Type cation exchange resin;
[0036] (3) Mg 2+Type II cation exchange resin column chromatography: using the activated Mg 2+ The clarified fermentation broth was subjected to chromatography using a cation exchange resin column to obtain a first chromatographic solution.
[0037] (4) First crystallization: The first chromatography solution is subjected to a first decolorization treatment and a first concentration treatment to obtain a first concentrate; the first concentrate is subjected to a first cooling crystallization and then filtered to obtain a first wet crystal and a first filtrate; the first wet crystal is washed with ethanol and then filtered to obtain a washed first wet crystal and an ethanol washing solution; the first wet crystal is dried to obtain magnesium α-ketoglutarate; the first filtrate and the ethanol washing solution are combined after ethanol recovery to obtain a processed solution;
[0038] (5) Strong acid H + Type II cation exchange resin chromatography: using strongly acidic H+ + The treatment solution was subjected to chromatography using a type cation exchange resin to obtain a second chromatographic solution.
[0039] (6) Second crystallization: The second chromatographic solution is subjected to a second decolorization treatment and a second concentration treatment to obtain a second concentrate; the second concentrate is subjected to a second cooling crystallization and then filtered to obtain a second wet crystal; the second wet crystal is dried to obtain α-ketoglutaric acid.
[0040] In step (1) of the present invention:
[0041] Preferably, the fermentation broth containing α-ketoglutarate is a fermentation broth obtained by microbial fermentation. For example, the fermentation broth is a fermentation broth produced by microbial fermentation using L-glutamic acid or L-glutamate sodium as a substrate, and the concentration of α-ketoglutarate in the fermentation broth is 75-85 g / L.
[0042] Preferably, the fermentation broth undergoes solid-liquid separation via an organic filter membrane, the pore size of which is 300 Da-1000 Da. For example, the pore size of the organic filter membrane can be 300 Da, 500 Da, 800 Da, 900 Da, or 1000 Da, etc.
[0043] In step (2) of this invention:
[0044] Preferably, the Mg 2+ The type of cationic resin is a polystyrene-based resin.
[0045] Preferably, the soluble magnesium salt is one of magnesium chloride, magnesium nitrate, or magnesium sulfate.
[0046] Preferably, the amount of the soluble magnesium salt solution used is the amount of Mg 2+ The volume of the cation exchange resin column is 3-6 times that of the Mg2+ column. For example, the amount of the soluble magnesium salt solution can be the same as the volume of the Mg2+ column.2+ The volume of the cation exchange resin column can be 3, 4, 5, or 6 times that of the cation exchange resin column.
[0047] Preferably, the mass concentration of the soluble magnesium salt solution is 8%-10%. For example, the mass concentration of the soluble magnesium salt solution can be 8%, 9%, or 10%, etc.
[0048] The flow rate of the soluble magnesium salt solution for rinsing is 0.5 BV / h.
[0049] In step (3) of the present invention:
[0050] Preferably, the sample loading temperature for the chromatography is 30-35℃. For example, the sample loading temperature can be 30℃, 32℃, or 35℃, etc.
[0051] Preferably, the loading flow rate for the chromatography is 0.2-0.6 BV / h. For example, the loading flow rate is 0.2 BV / h, 0.4 BV / h, or 0.6 BV / h, etc.
[0052] Preferably, the mass of α-ketoglutaric acid contained in the clarified fermentation broth is related to the mass of Mg. 2+ The volume ratio of the cation exchange resin is 1:6.5-1:8.5. For example, the mass ratio of α-ketoglutaric acid in the clarified fermentation broth to the mass of Mg... 2+ The volume ratio of the cation exchange resin can be 1:6.5, 1:7.0, 1:7.5, 1:8.0 or 1:8.5.
[0053] In step (4) of the present invention:
[0054] Preferably, the first decolorization treatment is as follows: the first chromatography solvent is decolorized with activated carbon at 50°C for 40 min to obtain a first decolorized solution, wherein the amount of activated carbon used is 0.3%-0.5% of the volume of the first chromatography solvent. For example, the amount of activated carbon used can be 0.3%, 0.4%, or 0.5% of the volume of the first chromatography solvent, etc.
[0055] Preferably, the first concentration process involves concentrating the first decolorizing solution under reduced pressure at a temperature of 55-65°C and a vacuum degree of -0.1 MPa until its solid content reaches 65%-75%, thus obtaining the first concentrated solution. For example, the temperature of the first concentration process can be 55°C, 60°C, or 65°C, and the solid content can be 65%, 70%, or 75%, etc.
[0056] Preferably, the first cooling crystallization is performed by: stirring and cooling the first concentrated liquid to below 10°C until a large amount of crystals precipitate, then maintaining the temperature at 4-6°C and stirring for 2 hours, and then refrigerating at below 4°C for 4-6 hours. For example, the temperature for maintaining the temperature can be 4°C, 5°C, or 6°C, and the refrigeration time can be 4 hours, 5 hours, or 6 hours.
[0057] Preferably, the first wet crystals are washed with ethanol, specifically by thoroughly stirring and washing with 1.0-1.5 BV of anhydrous ethanol for 0.5 h. For example, the amount of anhydrous ethanol used is 1.0 BV, 1.2 BV, or 1.5 BV, etc.
[0058] The second wet crystal drying process involves vacuum drying at 60°C for 4 hours.
[0059] In step (5) of this invention:
[0060] Preferably, the strong acid H + The cation exchange resin is a polystyrene-based resin, and the second chromatography solvent is a chromatography permeate with a pH ≤ 2.
[0061] Preferably, the sample loading temperature for the chromatography is 30-35℃, and the sample loading flow rate is 0.4-0.8 BV / h; the strongly acidic H... + The volume ratio of the cationic resin to the treatment solution is 1:1.5-1:2.5. For example, the loading temperature can be 30℃, 33℃, or 35℃, etc., and the loading flow rate can be 0.4 BV / h, 0.5 BV / h, 0.6 BV / h, or 0.8 BV / h, etc., and the strongly acidic H... + The volume ratio of the cation exchange resin to the treatment solution can be 1:1.5, 1:1.6, 1:1.7, 1:2.0, 1:2.2, 1:2.5, etc.
[0062] In step (6) of the present invention:
[0063] Preferably, the second decolorization process is as follows: the second chromatography solution is decolorized with activated carbon at room temperature for 60 min to obtain a second decolorized solution; the amount of activated carbon used is 0.5%-0.8% of the volume of the second chromatography solution, for example, the amount of activated carbon used is 0.5%, 0.7% or 0.8% of the volume of the second chromatography solution.
[0064] The second concentration process involves concentrating the second decolorizing solution under reduced pressure at a temperature of 60-63°C and a vacuum degree of -0.1 MPa until its solid content reaches 60%-65%, thus obtaining the second concentrated solution. For example, the reduced pressure concentration temperature can be 60°C, 62°C, or 63°C, and the solid content can be 60%, 62%, or 65%, etc.
[0065] Preferably, the second cooling crystallization process involves stirring the second concentrated liquid to cool it to 4-5°C and maintaining this temperature for 4-6 hours to allow crystallization. For example, the temperature can be 5°C, 4.5°C, or 5°C, and the crystallization time can be 4 hours, 5 hours, or 6 hours.
[0066] Preferably, the second wet crystal is dried by vacuum drying at 60°C for 4 hours.
[0067] The present application will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the present application.
[0068] In the following embodiments, the Mg 2+ Type cation exchange resin and the strongly acidic H + All cationic resins are polystyrene-based resins.
[0069] Example 1
[0070] This embodiment studies Mg 2+ The effects of different cation exchange chromatography methods and combinations of concentrated solids content on the purity and yield of Mg-AKG (magnesium α-ketoglutarate).
[0071] This embodiment uses L-glutamic acid as a substrate and the fermentation broth obtained through microbial fermentation as a raw material to produce magnesium α-ketoglutarate, wherein the fermentation broth contains 80 g / L of α-ketoglutarate. The production method specifically includes the following steps:
[0072] (1) Selection of fermentation broth: The fermentation broth obtained by microbial fermentation with L-glutamic acid as substrate is used as raw material broth, wherein the concentration of α-ketoglutarate in the fermentation broth is 80 g / L;
[0073] (2) Fermentation broth pretreatment: Microbial cells in the fermentation broth are removed by passing the broth through an organic filter membrane with a pore size of 500 Da to obtain a clear broth;
[0074] (3) Mg 2+ Activation of the cation exchange resin column: First, a 9% magnesium chloride solution is passed through the column at a flow rate of 0.5 BV / h. 2+ A type cation exchange resin column was used, with a volume five times the column volume. At this point, the pH of the effluent was the same as that of the magnesium chloride solution. Then, purified water was used to adjust the Mg... 2+ The cation exchange resin column was rinsed until the pH of the effluent was neutral, thus obtaining the activated Mg. 2+ Type cation exchange resin;
[0075] (4) Mg 2+ Type II cation exchange resin column chromatography: using the activated Mg 2+The clarified fermentation broth was subjected to chromatography using a cation exchange resin column, wherein the sample loading temperature was 35°C, to obtain the first chromatographic solution;
[0076] (5) Decolorization: Add 0.3% (W / V) of activated carbon to the first chromatography solution and decolorize at 50°C for 40 min to obtain the first decolorized solution;
[0077] (6) Concentration: The first decolorized solution is concentrated under reduced pressure at 60°C and -0.1 MPa to obtain the first concentrated solution;
[0078] (7) Crystallization: The first concentrated solution was stirred and cooled to below 10°C until a large amount of crystals precipitated. The solution was kept at 5°C and stirred for 2 h to crystallize, then refrigerated at below 4°C for 5 h. After filtration, the first wet crystals and the first filtrate were obtained. The first wet crystals were then thoroughly washed with 1.2 BV of anhydrous ethanol for 0.5 h, filtered, and dried under vacuum at 75°C for 4 h to obtain high-purity magnesium α-ketoglutarate. The first filtrate and the ethanol washing solution were combined after ethanol recovery and used as a processing solution for the separation and purification of α-ketoglutaric acid.
[0079] The effects of specific chromatography conditions and the combination of concentrated solids content on the purity and yield of Mg-AKG are shown in Table 1 below.
[0080] Table 1. Effects of chromatography conditions and concentration of solids on the purity and yield of Mg-AKG
[0081]
[0082] Example 2
[0083] This embodiment examines strongly acidic H₂ + The effect of different chromatography conditions on the purity and yield of AKG (α-ketoglutaric acid) produced using the solution from Example 1.
[0084] This embodiment uses the treatment solution from Example 1 as the raw material solution to produce α-ketoglutaric acid. The production method specifically includes the following steps:
[0085] (1) Strong acid H + Type II cation exchange resin chromatography: using strongly acidic H+ + The treatment solution was subjected to chromatography using a type cation exchange resin at a loading temperature of 35°C. The permeate with pH ≤ 2 was collected to obtain a second chromatographic solution.
[0086] (2) Decolorization: Add 0.5% activated carbon (W / V) to the second chromatography solution, stir at room temperature for 1 h to decolorize, and obtain the second decolorized solution;
[0087] (3) Concentration: The second decolorized solution is concentrated under reduced pressure at -0.1 MPa and 60°C until the solid content is 65% to obtain the second concentrated solution;
[0088] (4) Crystallization: The second concentrated liquid was stirred and cooled to 5°C, kept warm for 5 hours to crystallize, and then filtered to obtain the second wet crystals; the second wet crystals were dried under vacuum at 60°C for 4 hours to obtain the α-ketoglutaric acid product.
[0089] Strong acid H + The effects of different chromatography conditions on the purity and yield of AKG using the type cation exchange resin are shown in Table 2 below.
[0090] Table 2. Effects of different chromatography conditions on the purity and yield of AKG
[0091]
[0092] As shown in Tables 1 and 2, this invention first prepares magnesium α-ketoglutarate by Mg2+ type cation exchange resin chromatography, concentrates it under reduced pressure to co-crystallize magnesium α-ketoglutarate and α-ketoglutarate, separates the magnesium α-ketoglutarate, and then purifies α-ketoglutarate from the mother liquor of magnesium α-ketoglutarate crystallization using H+ type cation exchange resin. The resulting solution is concentrated and crystallized, co-producing α-ketoglutarate. This achieves closed-loop utilization of the mother liquor in the magnesium α-ketoglutarate production process, maximizing the utilization of raw material resources. Furthermore, the produced magnesium α-ketoglutarate has a purity ≥98% and a yield ≥75%, while the α-ketoglutarate has a purity ≥99% and a recovery rate ≥80%.
Claims
1. A method for co-producing magnesium α-ketoglutarate and α-ketoglutaric acid from fermentation broth, characterized in that, Includes the following steps: (1) Pretreatment of fermentation broth: The fermentation broth containing α-ketoglutaric acid was subjected to solid-liquid separation to obtain a clear fermentation broth; (2) Mg 2+ Activation of the cation exchange resin column: First, Mg is activated using a soluble magnesium salt solution. 2+ The cation exchange resin column was rinsed until the pH of the effluent was the same as that of the soluble magnesium salt solution, and then the Mg solution was rinsed with purified water. 2+ The cation exchange resin column was rinsed until the pH of the effluent was neutral, thus obtaining the activated Mg. 2+ Type cation exchange resin; (3) Mg 2+ Type II cation exchange resin column chromatography: using the activated Mg 2+ The clarified fermentation broth was subjected to chromatography using a cation exchange resin column to obtain a first chromatographic solution. (4) First crystallization: The first chromatographic solution is subjected to a first decolorization treatment and a first concentration treatment to obtain a first concentrated solution; The first concentrate is subjected to a first cooling crystallization and then filtered to obtain a first wet crystal and a first filtrate; the first wet crystal is washed with ethanol and then filtered to obtain a washed first wet crystal and an ethanol washing solution; the first wet crystal is dried to obtain magnesium α-ketoglutarate; the first filtrate and the ethanol washing solution are combined after ethanol recovery to obtain a processed solution; (5) Strong acid H + Type II cation exchange resin chromatography: using strongly acidic H+ + The treatment solution was subjected to chromatography using a type cation exchange resin to obtain a second chromatographic solution. (6) Second crystallization: The second chromatographic solution is subjected to a second decolorization treatment and a second concentration treatment to obtain a second concentrated solution; After the second concentrate is subjected to a second cooling and crystallization process, it is filtered to obtain a second wet crystal. After drying the second wet crystal, α-ketoglutaric acid is obtained.
2. The method for co-producing magnesium α-ketoglutarate and α-ketoglutaric acid from fermentation broth according to claim 1, characterized in that, In step (1), the solid-liquid separation is performed through an organic filter membrane, the pore size of which is 300 Da-1000 Da.
3. The method for co-producing magnesium α-ketoglutarate and α-ketoglutaric acid from fermentation broth according to claim 1, characterized in that, In step (2), the Mg 2+ The cationic resin is a polystyrene-based resin; the soluble magnesium salt is one of magnesium chloride, magnesium nitrate, or magnesium sulfate; the amount of the soluble magnesium salt solution used is [amount missing] of the Mg [concentration missing]. 2+ The volume of the cation exchange resin column is 3-6 times that of the column.
4. The method for co-producing magnesium α-ketoglutarate and α-ketoglutaric acid from fermentation broth according to claim 1, characterized in that, In step (3), the sample loading temperature for the chromatography is 30-35℃, and the sample loading flow rate is 0.2-0.6 BV / h; the mass of α-ketoglutaric acid contained in the clarified fermentation broth and the mass of Mg 2+ The volume ratio of the type cation exchange resin is 1:6.5-1:8.
5.
5. The method for co-producing magnesium α-ketoglutarate and α-ketoglutaric acid from fermentation broth according to claim 1, characterized in that, In step (4), the first decolorization treatment is as follows: the first chromatography solution is decolorized with activated carbon at 50°C for 40 min to obtain the first decolorized solution, wherein the amount of activated carbon used is 0.3%-0.5% of the volume of the first chromatography solution; the first concentration treatment is as follows: the first decolorized solution is concentrated under reduced pressure at a temperature of 55-65°C and a vacuum degree of -0.1MPa to a solid content of 65%-75% to obtain the first concentrated solution.
6. The method for co-producing magnesium α-ketoglutarate and α-ketoglutaric acid from fermentation broth according to claim 1, characterized in that, In step (4), the first cooling crystallization is: the first concentrated liquid is stirred and cooled to below 10°C until a large amount of crystals precipitate out, then kept at 4-6°C and stirred for 2 hours to crystallize, and then refrigerated below 4°C for 4-6 hours.
7. The method for co-producing magnesium α-ketoglutarate and α-ketoglutaric acid from fermentation broth according to claim 1, characterized in that, In step (5), the strong acid H + The cation exchange resin is a polystyrene-based resin, and the second chromatography solvent is a chromatography permeate with a pH ≤ 2.
8. The method for co-producing magnesium α-ketoglutarate and α-ketoglutaric acid from fermentation broth according to claim 1, characterized in that, In step (5), the sample loading temperature for the chromatography is 30-35℃, and the sample loading flow rate is 0.4-0.8 BV / h; the strongly acidic H... + The volume ratio of the cationic resin to the treatment solution is 1:1.5 to 1:2.
5.
9. The method for co-producing magnesium α-ketoglutarate and α-ketoglutaric acid from fermentation broth according to claim 1, characterized in that, In step (6), the second decolorization process is as follows: the second chromatography solution is decolorized with activated carbon at room temperature for 60 min to obtain the second decolorized solution, wherein the amount of activated carbon used is 0.5%-0.8% of the volume of the second chromatography solution; the second concentration process is as follows: the second decolorized solution is concentrated under reduced pressure at a temperature of 60-63℃ and a vacuum degree of -0.1MPa until its solid content is 60%-65% to obtain the second concentrated solution.
10. The method for co-producing magnesium α-ketoglutarate and α-ketoglutaric acid from fermentation broth according to claim 1, characterized in that, In step (6), the second cooling crystallization is: the second concentrate is stirred and cooled to 4-5℃, and kept at this temperature for 4-6 hours to crystallize.