A process for recovering succinic acid and malic acid from a succinic acid mother liquor

Abstract

The present application relates to the technical field of biological chemical industry, and discloses a method for recovering succinic acid and malic acid from succinic acid mother liquor, which comprises the following steps: after the succinic acid mother liquor is acidified, the succinic acid mother liquor is separated by a continuous chromatography, and the chromatography clear liquid containing succinic acid and malic acid is collected; the chromatography clear liquid is concentrated, cooled, crystallized, and centrifuged to obtain succinic acid crude product and filtrate; the filtrate is separated by a second continuous chromatography, and the second chromatography clear liquid containing malic acid is collected. The present application effectively separates and recovers succinic acid and malic acid in the succinic acid crystallization mother liquor through two continuous chromatographies, and the obtained products have good purity and high yield, and the problems in the prior art, such as low resolution selectivity of anion resin adsorption and resolution, use of a large amount of acid and alkali, and difficulty in treatment of a large amount of acid and alkali wastewater, are overcome, and the problems, such as large water consumption and high energy consumption in the process of separating succinic acid and malic acid from the mother liquor by two continuous chromatographies, are solved.

Description

Technical Field

[0001] This invention relates to the field of biochemical technology, and in particular to a method for recovering succinic acid and malic acid from succinic acid mother liquor. Background Technology

[0002] Succinic acid, also known as succinic acid, is a colorless or white, odorless crystal with a sour taste. It is soluble in water and is an important C4 platform compound with wide applications in biomedicine and polymer materials. Malic acid, also known as 2-hydroxysuccinic acid, is a white crystalline powder or crystalline solid with strong hygroscopic properties. It is readily soluble in water and ethanol and is widely used in food, cosmetics, medical products, and health supplements.

[0003] The main methods for industrial production of succinic acid include chemical methods, electrolysis methods, and fermentation methods. Among these, microbial fermentation has become a research hotspot both domestically and internationally in recent years due to its advantages such as utilizing renewable resources and fixing the greenhouse gas CO2. However, all of the above methods produce a certain amount of malic acid as a byproduct, which cannot be completely separated through concentration and crystallization. The succinic acid crystallization mother liquor obtained after pretreatment to remove impurities, cooling crystallization, and centrifugation can contain over 100 g / L of succinic acid and over 10 g / L of malic acid. With the expansion of malic acid applications, separating and recovering malic acid and succinic acid from the succinic acid crystallization mother liquor has significant economic value. However, achieving complete separation and recovery of succinic acid and malic acid from the fermentation broth remains an industry challenge.

[0004] Currently, common methods for separating malic acid and succinic acid include anion exchange resin adsorption and solvent extraction. Anion exchange resin adsorption involves adsorbing malic acid and succinic acid from the sample onto anion exchange resin, followed by elution with dilute sulfuric acid to obtain succinic acid and malic acid eluates. For example, invention patent CN110194714A discloses the use of a weakly basic anion exchange resin to adsorb malic acid and succinic acid from malic acid fermentation broth, followed by elution with dilute sulfuric acid, and the segmented collection and separation of succinic acid and malic acid. However, this method has drawbacks: the adsorption capacity of such anion exchange resins is not high, the water washing volume is large, and a large amount of acid and alkali reagents are required to regenerate the resin, resulting in a large amount of difficult-to-treat acid and alkali wastewater. Furthermore, the acid elution selectivity is low, leading to low product purity and yield. Solvent extraction, on the other hand, suffers from the problem of large amounts of organic solvents used, resulting in high process costs. Summary of the Invention

[0005] Based on the technical problems existing in the background technology, the present invention proposes a method for recovering succinic acid and malic acid from succinic acid mother liquor. The method uses two continuous chromatograms to effectively separate succinic acid and malic acid from the succinic acid crystallization mother liquor, and the obtained product has high purity, which improves the recovery and utilization of the crystallization mother liquor and increases economic benefits.

[0006] The present invention proposes a method for recovering succinic acid and malic acid from succinic acid mother liquor, the steps of which are as follows:

[0007] 1) Adjust the succinic acid mother liquor to acidity to obtain acidified succinic acid mother liquor;

[0008] 2) The acidified succinic acid mother liquor is introduced into a continuous chromatogram for separation, and the clear chromatogram containing succinic acid and malic acid is collected.

[0009] 3) Concentrate the chromatographic clear solution, cool it to crystallize, and centrifuge it to obtain crude succinic acid and filtrate;

[0010] 4) The filtrate is subjected to a two-stage continuous chromatography for separation, and the clear liquid of the two-stage chromatography containing malic acid is collected.

[0011] Furthermore, the succinic acid mother liquor is the fermentation broth remaining after succinic acid fermentation broth has been extracted and separated to obtain succinic acid;

[0012] Preferably, the succinic acid mother liquor contains 110-140 g / L of succinic acid and 10-30 g / L of malic acid.

[0013] Further, in step 1), the pH of the succinic acid mother liquor is adjusted to 1.0-3.0;

[0014] Preferably, after adjusting the succinic acid mother liquor to acidity, the method further includes: heating and filtering the acidified succinic acid mother liquor;

[0015] The heating temperature is 80-90℃ and maintained for 40-60 minutes.

[0016] Further, in step 2), the chromatographic column packing material for the continuous chromatography is a uniform-particle gel cation exchange resin, preferably LX-1850.

[0017] Further, the acidified succinic acid mother liquor is subjected to a continuous chromatographic separation process, including:

[0018] The acidified succinic acid mother liquor was loaded onto the column of the continuous chromatography column.

[0019] The loaded chromatographic column was eluted with pure water, and a clear chromatographic solution and a residual chromatographic solution containing succinic acid and malic acid were collected.

[0020] Preferably, the volume ratio of pure water to acidified succinic acid mother liquor is 1.7-2.0:1;

[0021] The pure water feed flow rate is 2-4 BV / h;

[0022] The volume ratio of chromatographic supernatant to chromatographic residue is 0.6-0.8:1;

[0023] The column temperature of the chromatographic column is 10-60℃.

[0024] Further, in step 3), the first chromatographic clear solution is concentrated until the succinic acid content is 350-450 g / L.

[0025] Further, in step 4), the chromatographic column packing material for the two-channel continuous chromatography is a uniform-particle gel cation exchange chromatography resin, preferably LX-1850.

[0026] Further, the filtrate is subjected to a two-stage continuous chromatogram for separation, including:

[0027] The filtrate of the acidified succinic acid mother liquor was loaded onto the column of the two-channel continuous chromatography.

[0028] The loaded chromatographic column was eluted with pure water, and the second chromatographic supernatant and chromatographic residue containing malic acid were collected.

[0029] Preferably, the volume ratio of pure water to filtrate is 2.3-3.0:1;

[0030] The feed flow rate of pure water is 2-4 BV / h;

[0031] The volume ratio of chromatographic supernatant to chromatographic residue is 0.6-0.8:1;

[0032] The column temperature of the chromatographic column is 10-60℃.

[0033] Furthermore, step 4) also includes: decolorizing, concentrating, and cooling the chromatographic solution containing malic acid to obtain crude malic acid.

[0034] Preferably, the method further includes redissolving and recrystallizing the crude malic acid, and drying it to obtain pure malic acid.

[0035] Furthermore, the chromatographic residue from the two continuous chromatograms is reused in the succinic acid mother liquor.

[0036] This invention effectively recovers succinic acid and malic acid from succinic acid crystallization mother liquor using two continuous chromatographic stages. First, a single continuous chromatographic stage separates the succinic acid and malic acid into a mixed solution. Succinic acid is then recovered from the mixture by cooling and crystallization, yielding crude succinic acid and a filtrate. Next, a second continuous chromatographic stage separates the malic acid from the filtrate. The filtrate from which malic acid has been separated can be reused in the succinic acid crystallization mother liquor. This invention utilizes continuous chromatography to fully recover the components from the succinic acid crystallization mother liquor, achieving good separation efficiency, high yield, and high product purity. It overcomes the problems of low selectivity, the use of large amounts of acid and alkali, and the difficult treatment of large amounts of acid and alkali wastewater generated by the existing anion exchange resin adsorption method, as well as the problems of high water consumption and high energy consumption associated with sequentially separating succinic acid and malic acid from the mother liquor using two continuous chromatographic stages. Detailed Implementation

[0037] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the embodiments.

[0038] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0039] This invention proposes a method for recovering succinic acid and malic acid from succinic acid mother liquor, characterized by the following steps:

[0040] 1) Adjust the succinic acid mother liquor to acidity to obtain acidified succinic acid mother liquor;

[0041] 2) The acidified succinic acid mother liquor is introduced into a continuous chromatogram for separation, and the clear chromatogram containing succinic acid and malic acid is collected.

[0042] 3) Concentrate the chromatographic clear solution, cool it to crystallize, and centrifuge it to obtain crude succinic acid and filtrate;

[0043] 4) The filtrate is subjected to a two-stage continuous chromatography for separation, and the clear liquid of the two-stage chromatography containing malic acid is collected.

[0044] The succinic acid mother liquor described in this application is the fermentation broth remaining after succinic acid fermentation broth has been extracted and separated to obtain succinic acid. Specifically, the extraction and separation of succinic acid includes: first filtering the succinic acid fermentation broth through a ceramic membrane to remove large molecular particles such as bacterial proteins from the system, then purifying it through an ultrafiltration membrane, followed by decolorization with activated carbon, concentration, cooling and crystallization, and centrifugation to obtain succinic acid crystals and crystallization mother liquor; the molecular weight cutoff of the ultrafiltration membrane is preferably 1000.

[0045] The succinic acid mother liquor of this application contains 110-140 g / L of succinic acid, 10-30 g / L of malic acid, and 20-35 g / L of inorganic salts. The pH of the succinic acid mother liquor is between 3.5 and 4.0. The main components of the inorganic salts are sodium sulfate, sodium phosphate, potassium sulfate, potassium phosphate, magnesium sulfate, etc.

[0046] To further improve the separation effect, in step 1), the pH of the succinic acid mother liquor is adjusted to 1.0-3.0; under this pH condition, the succinate and malate in the succinic acid mother liquor are effectively converted into succinic acid and malic acid.

[0047] To further improve the separation effect, after adjusting the succinic acid mother liquor to acidity, the process further includes: heating and filtering the acidified succinic acid mother liquor; the heating temperature is 80-90℃ and maintained for 40-60 minutes. During the acidification and heating process, soluble proteins in the succinic acid mother liquor denature and precipitate, which are then removed by filtration, thereby improving the purity of the succinic acid mother liquor.

[0048] The column packing material for a continuous chromatography step in this application is a uniform-particle gel cation exchange chromatography resin. During the resin selection process, it was found that, compared to other resins, the LX-1850 resin (particle size 280-320 μm) produced by Xi'an Lanxiao New Material Technology Co., Ltd., used for the separation of succinic acid and malic acid in succinic acid mother liquor has a smaller water-to-material ratio. Other resins generally have water-to-material ratios above 4.5, and their separation effects are poor.

[0049] Specifically, the acidified succinic acid mother liquor is subjected to a continuous chromatographic separation process, including:

[0050] The acidified succinic acid mother liquor was loaded onto the column of the continuous chromatography column.

[0051] The chromatographic column on which the sample has been loaded is eluted with pure water, and a first chromatographic clear liquid and a first chromatographic residue containing succinic acid and malic acid are collected. The first chromatographic clear liquid is a mixture rich in succinic acid and malic acid. All the succinic acid in the crystallization mother liquor is transferred to the first chromatographic clear liquid, and more than 88% of the malic acid is transferred to the first chromatographic clear liquid. The salt removal rate in the first chromatographic clear liquid can reach more than 76%. The first chromatographic residue contains inorganic salts and other impurities.

[0052] To further improve the separation effect, the water-to-material ratio (volume ratio of pure water to acidified succinic acid mother liquor) is controlled at 1.7-2.0:1; the feed flow rate of pure water is 2.5 BV / h; the volume ratio of chromatographic clear liquid to chromatographic residue is 0.6-0.8:1; and the column temperature is 10-60℃, preferably 60℃.

[0053] To further improve the recovery efficiency of succinic acid, the first chromatographic supernatant was concentrated to a succinic acid content of 350-450 g / L, followed by cooling and crystallization to obtain crude succinic acid. The obtained crude succinic acid can be further purified to produce pure succinic acid.

[0054] The column packing material for the two-stage continuous chromatography in this application is a uniform-particle gel cation exchange chromatography resin. During the resin selection process, it was found that, compared with other resins, the LX-1850 resin (resin particle size 280-320μm) produced by Xi'an Lanxiao Technology New Material Co., Ltd. has a smaller water-to-material ratio for the separation of malic acid, while other resins have a water-to-material ratio of more than 5 and poor separation effect.

[0055] In addition, the chromatographic clear liquid from one continuous chromatography is concentrated, crystallized, and filtered to obtain a filtrate. The volume of the filtrate is significantly reduced compared to the volume of the chromatographic clear liquid from one continuous chromatography, thereby reducing the processing volume of the two continuous chromatography stages.

[0056] Specifically, the filtrate is subjected to a two-stage continuous chromatography process for separation, including:

[0057] The filtrate of the acidified succinic acid mother liquor was loaded onto the column of the two-channel continuous chromatography.

[0058] The chromatographic column on which the sample has been loaded is eluted with pure water, and a second chromatographic clear liquid containing malic acid and a chromatographic residue are collected. The second chromatographic clear liquid is a high-purity malic acid solution, in which more than 98% of the malic acid in the filtrate is transferred to the second chromatographic clear liquid and it does not contain succinic acid. The removal rate of succinic acid in the second chromatographic clear liquid is 100%. The second chromatographic residue is a solution containing succinic acid and a small amount of impurities such as salt.

[0059] To further improve the separation effect, the water-to-material ratio (volume ratio of pure water to acidified succinic acid mother liquor) is controlled at 2.3-3.0:1; the feed flow rate of pure water is 3 BV / h; the volume ratio of chromatographic clear liquid to chromatographic residue is 0.6-0.8:1; and the column temperature is 10-60℃, preferably 60℃.

[0060] In this application, the separated malic acid-containing second-stage chromatographic clear liquid further includes: decolorizing, concentrating, and cooling the second-stage chromatographic clear liquid containing malic acid to obtain crude malic acid.

[0061] To obtain a higher purity malic acid product, the process also includes redissolving, recrystallizing, and drying the crude malic acid to obtain pure malic acid.

[0062] To improve recovery efficiency, the chromatographic residue from two continuous chromatograms can be reused in succinic acid mother liquor.

[0063] The technical solution of the present invention will now be described in detail through specific embodiments.

[0064] In the following examples, the succinic acid mother liquor was prepared by first filtering the succinic acid fermentation broth through a ceramic membrane to remove large molecular particles such as bacterial proteins, then purifying it through an ultrafiltration membrane (molecular weight cutoff: 1000), followed by activated carbon decolorization, concentration, cooling and crystallization, and centrifugation to separate the remaining fermentation broth after succinic acid crystallization. The succinic acid mother liquor contained 125 g / L of succinic acid, 18 g / L of malic acid, and 26 g / L of inorganic salts, and had a pH of 3.8.

[0065] The water-to-material ratio below refers to the volume ratio of pure water to the injected material; the clear-to-residue ratio below refers to the volume ratio of chromatographic clear liquid to chromatographic residue.

[0066] Example 1

[0067] The method for recovering succinic acid and malic acid from succinic acid mother liquor comprises the following steps:

[0068] 1) Acidify the succinic acid mother liquor with 60% sulfuric acid, adjust the pH value to 3.0, heat to 80℃ and maintain for 1 hour, filter to remove insoluble matter from the succinic acid mother liquor, and obtain acidified succinic acid mother liquor;

[0069] 2) The acidified succinic acid mother liquor was passed into a single-stage continuous chromatography apparatus with LX-1850 chromatographic packing material. The water-to-solid ratio was controlled at 1.7, the supernatant-to-residue ratio at 0.8, and the pure water feed flow rate at 2.5 BV / h. The supernatant was collected to recover succinic acid and malic acid. The succinic acid yield in the supernatant was 100%, the malic acid yield was 94.8%, and the desalination rate was 76.2%.

[0070] 3) The chromatographic clear solution was concentrated under vacuum at 70℃ to a succinic acid content of 427 g / L. The solution was then cooled to crystallize at 10℃ for 2 hours. After crystallization, the solution was centrifuged to obtain crude succinic acid and filtrate. The purity of the crude succinic acid was 97.2% and the yield was 82.3%. It can be further recycled in the refining workshop to prepare high-quality succinic acid.

[0071] 4) Pass the filtrate into a two-stage continuous chromatography apparatus with LX-1850 packing material, control the water-to-solid ratio at 2.3, the supernatant-to-residue ratio at 0.8, and the pure water feed flow rate at 3 BV / h. Collect the supernatant from the second chromatogram to recover malic acid. The malic acid yield in the obtained supernatant from the second chromatogram is 98.5%, and the succinic acid removal rate is 100%. The succinic acid residue from the second chromatogram can be reused in the succinic acid mother liquor to improve the yield.

[0072] 5) Add activated carbon to the second chromatographic clear liquid for decolorization. The amount of activated carbon added is controlled at 0.5% (v / w), the decolorization temperature is controlled at 60℃, and the decolorization time is controlled at 1h. Then filter to remove the activated carbon and collect the decolorized clear liquid. The transmittance of the decolorized clear liquid is 99.5%.

[0073] 6) The decolorized clear liquid was concentrated under vacuum at 70℃ to a malic acid content of 1203g / L, cooled and crystallized at 10℃ for 2 hours. After crystallization, the liquid was centrifuged to obtain crude malic acid with a purity of 97.1% and a yield of 71.8%.

[0074] 7) The crude malic acid product is processed through a series of refined processes, including dissolving in water, evaporation and crystallization, centrifugation and drying, to obtain the finished product. The purity of malic acid is 99.1%, and all other indicators meet the requirements of GB1886.40.

[0075] Example 2

[0076] The method for recovering succinic acid and malic acid from succinic acid mother liquor comprises the following steps:

[0077] 1) Acidify the succinic acid mother liquor with 60% sulfuric acid, adjust the pH value to 1.0, heat to 90℃ and maintain for 40 min, filter to remove insoluble matter from the succinic acid mother liquor, and obtain acidified succinic acid mother liquor;

[0078] 2) The acidified succinic acid mother liquor was passed into a single-stage continuous chromatography apparatus with LX-1850 chromatographic packing material. The water-to-solid ratio was controlled at 1.7, the supernatant-to-residue ratio at 0.6, and the pure water feed flow rate at 2.2 BV / h. The supernatant was collected to recover succinic acid and malic acid. The succinic acid yield was 100%, the malic acid yield was 91.4%, and the desalination rate was 81.7% in the supernatant.

[0079] 3) The chromatographic clear solution was concentrated under vacuum at 70℃ to a succinic acid content of 429 g / L, then cooled to crystallize at 20℃ for 4 hours. After crystallization, the solution was centrifuged to obtain crude succinic acid and filtrate. The purity of the crude succinic acid was 97.0%, which can be further reused in the refining workshop to prepare high-quality succinic acid.

[0080] 4) Pass the filtrate into a two-stage continuous chromatography apparatus with LX-1850 chromatographic packing material, control the water-to-solid ratio at 2.3, the supernatant-to-residue ratio at 0.6, and the pure water feed flow rate at 2.4 BV / h. Collect the supernatant from the second chromatogram to recover malic acid. The malic acid yield in the obtained supernatant from the second chromatogram is 98.2%, and the succinic acid removal rate is 100%. The succinic acid residue from the second chromatogram can be reused in the succinic acid mother liquor to improve the yield.

[0081] 5) Add activated carbon to the second chromatographic clear liquid for decolorization. The amount of activated carbon added is controlled at 1% (v / w), the decolorization temperature is controlled at 60℃, and the decolorization time is controlled at 1h. Then filter to remove the activated carbon and collect the decolorized clear liquid. The transmittance of the decolorized clear liquid is 99.5%.

[0082] 6) The decolorized clear liquid was concentrated under vacuum at 70℃ to a malic acid content of 1223g / L, cooled and crystallized at 20℃ for 4 hours. After crystallization, it was centrifuged to obtain crude malic acid with a purity of 96.9%.

[0083] 7) The crude malic acid product is processed through a series of refined processes, including dissolving in water, evaporation and crystallization, centrifugation and drying, to obtain the finished product. The purity of malic acid is 99.0%, and all other indicators meet the requirements of GB1886.40.

[0084] Example 3

[0085] The method for recovering succinic acid and malic acid from succinic acid mother liquor comprises the following steps:

[0086] 1) Acidify the succinic acid mother liquor with 60% sulfuric acid, adjust the pH value to 1.5, heat to 80℃ and maintain for 50 min, filter to remove insoluble matter from the succinic acid mother liquor, and obtain acidified succinic acid mother liquor;

[0087] 2) The acidified succinic acid mother liquor was passed into a single-stage continuous chromatography apparatus with LX-1850 chromatographic packing material. The water-to-solid ratio was controlled at 2.0, the supernatant-to-residue ratio at 0.8, and the pure water feed flow rate at 2.5 BV / h. The supernatant was collected to recover succinic acid and malic acid. The succinic acid yield was 100%, the malic acid yield was 91.6%, and the desalination rate was 85.3% in the supernatant.

[0088] 3) The chromatographic clear solution was concentrated under vacuum at 70℃ to a succinic acid content of 405 g / L. The solution was then cooled to crystallize at 20℃ for 4 hours. After crystallization, the solution was centrifuged to obtain crude succinic acid and filtrate. The purity of the crude succinic acid was 97.8%, which can be further reused in the refining workshop to prepare high-quality succinic acid.

[0089] 4) Pass the filtrate into a two-stage continuous chromatography apparatus with LX-1850 chromatographic packing material, control the water-to-solid ratio at 3.0, the supernatant-to-residue ratio at 0.8, and the pure water feed flow rate at 3.5 BV / h. Collect the supernatant from the second chromatogram to recover malic acid. The malic acid yield in the obtained supernatant from the second chromatogram is 99.5%, and the succinic acid removal rate is 100%. The succinic acid residue from the second chromatogram can be reused in the succinic acid mother liquor to improve the yield.

[0090] 5) Add activated carbon to the second chromatographic clear liquid for decolorization. The amount of activated carbon added is controlled at 1% (v / w), the decolorization temperature is controlled at 60℃, and the decolorization time is controlled at 1h. Then filter to remove the activated carbon and collect the decolorized clear liquid. The transmittance of the decolorized clear liquid is 99.8%.

[0091] 6) The decolorized clear liquid was concentrated under vacuum at 70℃ to a malic acid content of 1233 gg / L, cooled to crystallize at 20℃ for 4 hours, and then centrifuged to obtain crude malic acid with a purity of 97.7%.

[0092] 7) The crude malic acid product is processed through a series of refined processes, including dissolving in water, evaporation and crystallization, centrifugation and drying, to obtain the finished product. The purity of malic acid is 99.5%, and all other indicators meet the requirements of GB1886.40.

[0093] Example 4

[0094] The method for recovering succinic acid and malic acid from succinic acid mother liquor comprises the following steps:

[0095] 1) Acidify the succinic acid mother liquor with 60% sulfuric acid, adjust the pH value to 2.0, heat to 85℃ and maintain for 40 min, filter to remove insoluble matter from the succinic acid mother liquor, and obtain acidified succinic acid mother liquor;

[0096] 2) The acidified succinic acid mother liquor was passed into a single-stage continuous chromatography apparatus with LX-1850 chromatographic packing material. The water-to-solid ratio was controlled at 2.0, the supernatant-to-residue ratio at 0.6, and the pure water feed flow rate at 3 BV / h. The supernatant was collected to recover succinic acid and malic acid. The succinic acid yield in the supernatant was 100%, the malic acid yield was 88.9%, and the desalination rate was 81.2%.

[0097] 3) The chromatographic clear solution was concentrated under vacuum at 70°C to a succinic acid content of 447 g / L. The solution was then cooled to crystallize at 20°C for 4 hours. After crystallization, the solution was centrifuged to obtain crude succinic acid and filtrate. The crude succinic acid had a purity of 97.5% and could be further reused in the refining workshop to prepare high-quality succinic acid.

[0098] 4) Pass the filtrate into a two-stage continuous chromatography apparatus with LX-1850 chromatographic packing material, control the water-to-solid ratio at 3.0, the supernatant-to-residue ratio at 0.6, and the pure water feed flow rate at 3 BV / h. Collect the supernatant from the second chromatogram to recover malic acid. The malic acid yield in the obtained supernatant from the second chromatogram is 98.9%, and the succinic acid removal rate is 100%. The succinic acid residue from the second chromatogram can be reused in the succinic acid mother liquor to improve the yield.

[0099] 5) Add activated carbon to the chromatographic clear solution for decolorization. The amount of activated carbon added is controlled at 1% (v / w), the decolorization temperature is controlled at 80℃, and the decolorization time is controlled at 0.5h. Then filter to remove the activated carbon and collect the decolorized clear solution. The decolorized clear solution has a light transmittance of 99.7%.

[0100] 6) The decolorized clear liquid was concentrated under vacuum at 80℃ to a malic acid content of 1237g / L, cooled and crystallized at 20℃ for 4 hours. After crystallization, the liquid was centrifuged to obtain crude malic acid with a purity of 97.5%.

[0101] 7) The crude malic acid product is processed through a series of refined processes, including dissolving in water, evaporation and crystallization, centrifugation and drying, to obtain the finished product. The purity of malic acid is 99.3%, and all other indicators meet the requirements of GB1886.40.

[0102] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for recovering succinic acid and malic acid from succinic acid mother liquor, characterized in that, The steps are as follows: 1) Adjust the succinic acid mother liquor to acidity to obtain acidified succinic acid mother liquor; the succinic acid mother liquor is the fermentation broth remaining after succinic acid is extracted and separated from the succinic acid fermentation broth; the succinic acid content in the succinic acid mother liquor is 110-140 g / L, and the malic acid content is 10-30 g / L; 2) The acidified succinic acid mother liquor is introduced into a continuous chromatography column for separation, and the clear chromatographic solution containing succinic acid and malic acid is collected; the chromatographic column packing material of the continuous chromatography column is LX-1850 uniform granular gel cation exchange chromatography resin. 3) Concentrate the chromatographic clear solution, cool it to crystallize, and centrifuge it to obtain crude succinic acid and filtrate; 4) The filtrate is introduced into a two-stage continuous chromatogram for separation, and the clear liquid containing malic acid in the two-stage continuous chromatogram is collected; the chromatographic column packing material of the two-stage continuous chromatogram is LX-1850 uniform granular gel cation exchange resin.

2. The method according to claim 1, characterized in that, In step 1), the pH of the succinic acid mother liquor is adjusted to 1.0-3.

0.

3. The method according to claim 2, characterized in that, After adjusting the succinic acid mother liquor to acidity, the process further includes: heating and filtering the acidified succinic acid mother liquor; the heating temperature is 80-90℃ and maintained for 40-60 minutes.

4. The method according to claim 1, characterized in that, The acidified succinic acid mother liquor is subjected to a continuous chromatographic separation process, including: The acidified succinic acid mother liquor was loaded onto the column of the continuous chromatography column. The loaded chromatographic column was eluted with pure water, and a clear chromatographic solution containing succinic acid and malic acid and a residual chromatographic solution were collected.

5. The method according to claim 4, characterized in that, The volume ratio of pure water to acidified succinic acid mother liquor is 1.7-2.0:1; The pure water feed flow rate is 2-4 BV / h; The volume ratio of chromatographic supernatant to chromatographic residue is 0.6-0.8:1; The column temperature of the chromatographic column is 10-60℃.

6. The method according to claim 1, characterized in that, In step 3), the chromatographic clear solution is concentrated until the succinic acid content is 350-450 g / L.

7. The method according to claim 1, characterized in that, The filtrate is then subjected to a two-stage continuous chromatogram for separation, including: The filtrate of the acidified succinic acid mother liquor was loaded onto the column of the two-channel continuous chromatography. The loaded chromatographic column was eluted with pure water, and the secondary chromatographic supernatant and chromatographic residue containing malic acid were collected.

8. The method according to claim 7, characterized in that, The volume ratio of pure water to filtrate is 2.3-3.0:1; The feed flow rate of pure water is 2-4 BV / h; The volume ratio of chromatographic supernatant to chromatographic residue is 0.6-0.8:1; The column temperature of the chromatographic column is 10-60℃.

9. The method according to claim 1, characterized in that, Step 4) also includes: decolorizing, concentrating, and cooling the chromatographic solution containing malic acid to obtain crude malic acid.

10. The method according to claim 9, characterized in that, It also includes redissolving, recrystallizing, and drying crude malic acid to obtain pure malic acid.

11. The method according to claim 7, characterized in that, The chromatographic residue from the two continuous chromatograms is reused in the succinic acid mother liquor.