Process for the extraction of succinic acid from a fermentation broth of malic acid

Abstract

The present application relates to the separation of fermentation liquor, and discloses a method for extracting succinic acid from malic acid fermentation liquor. The method comprises the following steps: (1) solid-liquid separation I of the fermentation liquor, and collection of liquid phase I; (2) mixing and standing of the liquid phase I, polyaluminum chloride, polyacrylamide and diatomite, and then solid-liquid separation II and concentration, and collection of concentrated liquid; (3) pH adjustment of the concentrated liquid to 1-3, and then obtaining acidified liquid; (4) solid-liquid separation III of the acidified liquid, and then obtaining liquid phase II; (5) decolorization and separation of the liquid phase II, and then obtaining succinic acid. The method is free of organic pollution, environment-friendly, and can effectively improve the purity and yield of the prepared succinic acid.

Description

Technical Field

[0001] This invention relates to the separation of fermentation broth, and more specifically to a method for extracting succinic acid from malic acid fermentation broth. Background Technology

[0002] Succinic acid, also known as succinic acid, is an important "C4 platform compound" used as an important organic chemical raw material and intermediate. It is widely used in food, medicine, agriculture and other fields. Succinic acid is also a direct raw material for the synthesis of biodegradable plastics PBS and PHS.

[0003] Succinic acid is mainly synthesized through chemical or biological methods. Chemical methods primarily use n-butane as the starting material, which is obtained through the synthesis of maleic anhydride followed by catalytic hydrogenation or electrolytic reduction. Fermentation methods utilize bacteria or other microorganisms to produce succinic acid and its derivatives from starch, sugar, or other waste materials.

[0004] The separation of malic acid fermentation byproducts and the comprehensive utilization of waste are key technologies in the downstream separation process of malic acid fermentation by microorganisms. Separating succinic acid from malic acid fermentation broth is of significant practical importance for reducing production costs, increasing the added value of byproducts, and enriching the product structure of malic acid producers. Because malic acid, succinic acid, fumaric acid, and oxaloacetic acid exhibit similar solubility in most solvents, it is relatively difficult to separate succinic acid from complex mixed acids.

[0005] In the prior art, invention patent application number CN202010625145.6 discloses a method for separating malic acid and succinic acid. The process can be simplified as: L-malic acid fermentation broth - primary acidification - filtration - cation exchange - anion exchange adsorption - desorption separation. While this extraction method is relatively simple, it is not suitable for fermentation broths with complex compositions and high protein content. Furthermore, the purity of the obtained succinic acid is low, and the presence of other impurities is ignored. Patent application number 202010773982.3 discloses a method for separating and purifying succinic acid from mixed dicarboxylic acid residues: the mixed dicarboxylic acid residues are dispersed in a haloalkanes to form a mixed solution, glutaric acid is added, the mixture is heated to a specific temperature, and after stirring and maintaining the temperature, solid-liquid separation is performed, with the obtained solid being the crude succinic acid. This method introduces organic solvents and is designed for solid residues, making it unsuitable for large-volume fermentation broths. Summary of the Invention

[0006] The purpose of this invention is to overcome the problems of insufficient purity of succinic acid obtained by existing technologies or the presence of organic pollution during the purification process, and to provide a method for extracting succinic acid from malic acid fermentation broth. This method is free from organic pollution, environmentally friendly, and can effectively improve the purity and yield of the obtained product.

[0007] To achieve the above objectives, the present invention provides a method for extracting succinic acid from malic acid fermentation broth, comprising the following steps:

[0008] (1) Separate the fermentation broth into solid and liquid phases I and collect the liquid phase I;

[0009] (2) After mixing liquid phase I with polyaluminum chloride, polyacrylamide and diatomaceous earth and allowing it to stand, solid-liquid separation II and concentration are performed, and the concentrated liquid is collected.

[0010] (3) After adjusting the pH of the concentrated solution to 1-3, an acidified solution is obtained;

[0011] (4) The acidified liquid is separated into solid and liquid phases III to obtain liquid phase II;

[0012] (5) Decolorize and separate the liquid phase II to obtain succinic acid.

[0013] Preferably, in step (2), the total amount of the polymeric alumina, the polyacrylamide, and the diatomaceous earth added is 2-4g relative to 100g of the liquid phase I.

[0014] More preferably, the mass ratio of the polyaluminum chloride, the polyacrylamide, and the diatomaceous earth is 10:0.005-0.02:10-30.

[0015] Preferably, in step (2), the concentration step includes concentrating the liquid obtained from the solid-liquid separation II to 1 / 6-1 / 4 of its original volume.

[0016] Preferably, in step (5), the decolorization step includes mixing the liquid phase II and the decolorizing agent for decolorization, and obtaining a decolorized liquid after solid-liquid separation IV.

[0017] More preferably, the decolorizing agent contains activated carbon, aluminum sulfate, and sodium aluminate;

[0018] The mass ratio of the activated carbon, the aluminum sulfate, and the sodium aluminate is 1:0.03-0.1:0.05-0.1.

[0019] Preferably, the separation step includes: ultrafiltration, ion exchange adsorption, dialysis, and crystallization of the decolorizing solution.

[0020] More preferably, the ultrafiltration conditions include: a filter pore size of less than or equal to 0.05 μm and a pressure of 0.6-1.5 bar.

[0021] Preferably, the dialysis is electrodialysis, the membrane used in the electrodialysis is a homogeneous polyethylene ion exchange membrane, and the conditions of the electrodialysis include: voltage 200-300V, feed flow rate 100-200L / h, time 3-6h, and feed-to-output volume ratio 1.2-1.6:1.

[0022] Preferably, the crystallization process includes concentration and cooling crystallization.

[0023] More preferably, the cooling crystallization method includes: stirring and crystallizing at a temperature of 45-55°C, and then adding seed crystals to grow crystals.

[0024] Preferably, the solid-liquid separation I, the solid-liquid separation II, and the solid-liquid separation III are plate and frame filters, and the filter cloth pore size of the plate and frame filter is less than or equal to 48 μm.

[0025] Through the above technical solution, this invention effectively improves the yield and purity of succinic acid by separating the fermentation broth into solid and liquid phases, mixing it with polyaluminum chloride, polyacrylamide, and diatomaceous earth, allowing it to stand, and then performing multiple solid-liquid separation, acidification, decolorization, and separation processes. Furthermore, this method uses simple equipment, the separation process is environmentally friendly, and it does not require the use of polluting reagents, thus avoiding environmental pollution. Attached Figure Description

[0026] Figure 1 This is the liquid phase diagram of the succinic acid sample;

[0027] Figure 2 It is succinic acid prepared in Example 1. Detailed Implementation

[0028] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0029] As mentioned above, the present invention provides a method for extracting succinic acid from malic acid fermentation broth, comprising the following steps:

[0030] (1) Separate the fermentation broth into solid and liquid phases I and collect the liquid phase I;

[0031] (2) After mixing liquid phase I with polyaluminum chloride, polyacrylamide and diatomaceous earth and allowing it to stand, solid-liquid separation II and concentration are performed, and the concentrated liquid is collected.

[0032] (3) After adjusting the pH of the concentrated solution to 1-3, an acidified solution is obtained;

[0033] (4) The acidified liquid is separated into solid and liquid phases III to obtain liquid phase II;

[0034] (5) Decolorize and separate the liquid phase II to obtain succinic acid.

[0035] According to the present invention, the malic acid fermentation broth can be any fermentation broth capable of producing malic acid through biological fermentation. As a specific embodiment of the present invention, the fermentation broth can be a *Aspergillus niger* fermentation broth, wherein the *Aspergillus niger* strain can be RG0095 or other *Aspergillus niger* strains. As a specific embodiment of the present invention, the RG0095 strain is cultured in shake flasks to obtain a seed culture, which is then inoculated into a fermentation medium for fermentation to obtain an L-calcium malate fermentation broth. The fermentation broth after malic acid extraction is the fermentation broth, which contains succinic acid. Specifically, the shake flask culture time is 3 days, and the inoculation amount of the seed culture is 2 × 10⁻⁶. 6 The fermentation conditions were: cfu / mL, temperature 30℃, rotation speed 220 r / min, and time 5 days.

[0036] The fermentation medium may include carbon sources, nitrogen sources, inorganic salts, and trace elements. The selection of carbon sources, nitrogen sources, inorganic salts, and trace elements can be determined by the experimenter based on the actual situation. As a specific embodiment of the present invention, the fermentation medium includes: 160 g / L glucose, 6 g / L bacterial peptone, 0.15 g / L anhydrous potassium dihydrogen phosphate, 0.15 g / L anhydrous dipotassium hydrogen phosphate, 0.1 g / L magnesium sulfate heptahydrate, 0.1 g / L calcium chloride dihydrate, 0.005 g / L sodium chloride, 0.005 g / L ferrous sulfate heptahydrate, 0.001 g / L anhydrous citric acid, and 120 g / L calcium carbonate.

[0037] The RG0095 strain can be obtained commercially or from wild strains preserved in the laboratory and screened after mutagenesis.

[0038] According to the present invention, the pH can be adjusted by adding an acid solution to the concentrate. This acid solution can be sulfuric acid, hydrochloric acid, or other available acids. The adjusted pH can be 1-3, specifically 1, 1.5, 2, 2.5, 3, or any value within the range of any two of the above values. Preferably, the adjusted pH is 1.5-2.

[0039] During their research, the inventors discovered that the method for extracting succinic acid from malic acid fermentation broth provided by this invention, through solid-liquid separation of the fermentation broth followed by mixing with polyaluminum chloride, polyacrylamide, and diatomaceous earth and allowing it to stand, and then undergoing multiple solid-liquid separation, acidification, decolorization, and separation processes, can effectively improve the yield and purity of succinic acid. Furthermore, this method uses simple equipment, the separation process is environmentally friendly, and it does not require the use of polluting reagents, thus avoiding environmental pollution.

[0040] According to the present invention, specifically, polymeric alumina and polyacrylamide can be added to liquid phase I in the form of aqueous solution or suspension. The concentration of the aqueous solution or suspension can be determined by the experimenter according to the actual situation. Preferably, the concentration of the polymeric alumina aqueous solution or polymeric alumina suspension can be 5-15% by mass, and the concentration of the polyacrylamide aqueous solution or polyacrylamide suspension can be 1.5-7.5% by mass.

[0041] Preferably, in step (2), the total amount of the polyalumina, polyacrylamide, and diatomaceous earth added relative to 100g of the liquid phase I is 2-4g, specifically 2g, 2.5g, 3g, 3.5g, 4g, or any value within the range formed by any two of the above values. Studies have found that adding polyalumina, polyacrylamide, and diatomaceous earth within the above content range to the liquid phase I can improve the separation effect of succinic acid from other inorganic and organic impurities, thereby further improving the purity of the obtained succinic acid. Further preferably, considering a further improvement in the purity of the obtained succinic acid, the mass ratio of the polyaluminum chloride, polyacrylamide, and diatomaceous earth is 10:0.005-0.02:10-30.

[0042] According to the present invention, preferably, in step (3), the concentration step includes concentrating the liquid obtained from the solid-liquid separation II to 1 / 6-1 / 4 of the original volume.

[0043] Preferably, in step (5), the decolorization step includes mixing the liquid phase II and the decolorizing agent for decolorization, followed by solid-liquid separation IV to obtain a decolorized solution. This solid-liquid separation V can be filtration, centrifugation, etc., preferably filtration. After decolorization, the purity of the obtained succinic acid can be further improved. Further preferably, to further improve the purity of the obtained succinic acid, the decolorizing agent includes activated carbon, aluminum sulfate, and sodium aluminate. More preferably, the amount of the decolorizing agent added is 1-3g relative to 100g of the liquid phase III. Further preferably, to further improve the decolorization effect, the mass ratio of the activated carbon, aluminum sulfate, and sodium aluminate is 1:0.03-0.1:0.05-0.1.

[0044] In order to further improve the purity and yield of succinic acid, the separation step preferably includes: ultrafiltration, ion exchange adsorption, dialysis and crystallization of the decolorized solution.

[0045] Preferably, the ultrafiltration conditions include: a filter pore size less than or equal to 0.05 μm and a pressure of 0.6-1.5 bar. Under these ultrafiltration conditions, organic and inorganic impurities in the liquid phase can be effectively filtered, thereby further improving the purity of the obtained succinic acid.

[0046] Preferably, the dialysis is electrodialysis, and the membrane used for electrodialysis is a homogeneous polyethylene ion exchange membrane. The electrodialysis conditions include: voltage 200-300V, feed flow rate 100-200L / h, time 3-6h, and feed-to-effect volume ratio 1.2-1.6:1. Under the above dialysis conditions, the purity of the obtained succinic acid can be further improved. More preferably, the electrodialysis conditions include: voltage 200-250V, feed flow rate 100-150L / h, time 4-6h, and feed-to-effect volume ratio 1.2-1.3:1.

[0047] According to the present invention, preferably, the crystallization process includes concentration and cooling crystallization. Further preferably, considering the need to further improve the purity of the obtained succinic acid, the concentration conditions include concentrating the liquid phase to a succinic acid content of 160-200 g / L; the cooling crystallization method includes: stirring crystallization at a temperature of 45-55°C, adding seed crystals, and then growing the crystals. More preferably, the crystal growth time is 0.5-2 h. As a specific embodiment of the present invention, the crystallization is carried out by stirring crystallization at 50°C, adding seed crystals, growing the crystals for 1 h, first cooling to 20°C at a rate of 1°C / h, then gradually cooling to 10°C at a rate of 0.5°C / h, and then separating the solid and liquid by vacuum filtration or centrifugation.

[0048] The solid-liquid separation I, solid-liquid separation II, and solid-liquid separation III can be any solid-liquid separation method. Preferably, solid-liquid separation I, solid-liquid separation II, and solid-liquid separation III are all plate and frame filtration, and the pore size of the filter cloth of the plate and frame filter is less than or equal to 48 μm. Using plate and frame filtration can separate succinic acid from impurities, thereby further improving the purity of the obtained succinic acid. More preferably, the number of times solid-liquid separation I, solid-liquid separation II, and solid-liquid separation III are performed can be 2-3 times each.

[0049] According to the present invention, the method preferably includes drying and sieving the succinic acid, wherein the drying conditions include a temperature of 60-100°C and a time of 5-8 hours. The drying can be any drying method; in one specific embodiment of the present invention, the drying is performed using a hot air oven.

[0050] According to a particularly preferred embodiment of the present invention, a method for extracting succinic acid from malic acid fermentation broth is provided, comprising the following steps:

[0051] (1) The fermentation broth was filtered through a plate and frame filter under the condition that the filter cloth pore size was less than or equal to 48 μm, and the liquid phase I was collected.

[0052] (2) The liquid phase I is mixed with polyaluminum chloride, polyacrylamide and diatomaceous earth and allowed to stand. Then, the mixture is filtered through a plate and frame filter under the condition that the filter cloth pore size is less than or equal to 48 μm to obtain a liquid. The liquid is concentrated to 1 / 6-1 / 4 of the original volume to obtain a concentrated liquid.

[0053] Relative to 100g of the liquid phase I, the total amount of the polymeric alumina, the polyacrylamide, and the diatomaceous earth added is 2-3.5g, and the mass ratio of the polymeric aluminum chloride, the polyacrylamide, and the diatomaceous earth is 10:0.3-1:10-15;

[0054] (3) The concentrated solution and sulfuric acid solution were mixed and their pH was adjusted to 1-3 to obtain an acidified solution;

[0055] (4) The acidified liquid is filtered through a plate and frame filter under the condition that the filter cloth pore size is less than or equal to 48 μm to obtain liquid phase II;

[0056] (5) The liquid phase III and the decolorizing agent are mixed at a mass ratio of 100:1-3 for decolorization, and the mixture is filtered to obtain a decolorized liquid; in the decolorizing agent, the mass ratio of activated carbon, aluminum sulfate and sodium aluminate is 1:0.03-0.1:0.05-0.1;

[0057] (6) The decolorizing solution is subjected to ultrafiltration (the pore size of the ultrafiltration membrane is less than or equal to 0.05 μm, and the pressure is 0.6-1.5 bar) to obtain ultrafiltrate;

[0058] (7) The ultrafiltrate is treated with ion exchange resin at a flow rate of 1-2 BV / h and the filtrate is collected.

[0059] (8) The filtrate is subjected to electrodialysis to obtain electrodialysis solution; the membrane used for electrodialysis is a polyethylene homogeneous ion exchange membrane, the operating voltage is 200-300V, the feed flow rate is 100-200L / h, the treatment time is 3-6 hours, and the feed-to-output volume ratio is 1.2-1.6.

[0060] (9) The electrodialysis solution is concentrated until the concentration in the succinic acid solution is 160-200 g / L, and the concentrated solution is stirred and crystallized at a temperature of 45-55℃. After adding seed crystals, the solution is cooled to 20℃ at a rate of 1℃ / h, and then cooled to 10℃ at a rate of 0.5℃ / h. The solid and liquid are separated by vacuum filtration or centrifugation.

[0061] (10) Dry the crystallized solid in a hot air oven at 80°C for 5-8 hours, and then sieve it to obtain the finished product.

[0062] The succinic acid obtained by the above method has high purity, and the equipment used is simple. The separation process is environmentally friendly and does not require the use of reagents that cause environmental pollution.

[0063] The present invention will be described in detail below through examples. In the following examples, the concentration of succinic acid was determined by HPLC; the HPLC instrument was purchased from Shimadzu Corporation, model: LC-40; polyaluminum chloride, polyacrylamide, diatomaceous earth, and activated carbon were all commercially available products from Sinopharm Chemical Reagent Co., Ltd.

[0064] The L-malate calcium fermentation broth used below was prepared by fermentation with RG0095 strain. The L-malate calcium fermentation broth contained 170 g / L of L-malic acid, 12 g / L of succinic acid, and 2 g / L of fumaric acid.

[0065] Example 1

[0066] (1) Solid-liquid separation was carried out in 1000L of fermentation broth containing L-calcium malate by plate and frame filter press with filter cloth pore size of 48μm. The initial filtrate was filtered a second time. When the filter cake was formed and the filtrate was clear, the filtrate was collected.

[0067] (2) Add 1.0% polyaluminum chloride (PAC) by weight of the filtrate obtained in step (1). The PAC flocculant is prepared in advance as a 10% aqueous solution by weight. Slowly pour it into the fermentation broth and stir at 60 rpm for 5 min. Then slowly add 100 ppm polyacrylamide (PAC) by weight. The PAC flocculant is prepared in advance as a 5‰ aqueous solution by weight. Adjust the stirring speed to 100 rpm and stir for 10 min. Then add 2.0% diatomaceous earth, stir evenly, and let stand to obtain a mixed solution.

[0068] (3) The mixture obtained in step (2) is separated into solid and liquid by a plate and frame filter press with a filter cloth pore size of 400 mesh. The initial filtrate is filtered a second time. When the filter cake is formed and the filtrate is clear, the filtrate is collected.

[0069] (4) Concentrate the filtrate from step (3) under reduced pressure to 1 / 6 of its original volume to obtain a concentrated solution;

[0070] (5) Add sulfuric acid to the concentrated solution obtained in step (4) to adjust the pH to 1.0 to obtain an acidified solution;

[0071] (6) The acidified liquid obtained in step (5) is separated into solid and liquid by a plate and frame filter press with a filter cloth pore size of 300 mesh. The initial filtrate is filtered a second time. When the filter cake is formed and the filtrate is clear, the filtrate is collected.

[0072] (7) Add activated carbon with a final mass concentration of 1% to the filtrate, decolorize at 60°C for 5 hours, and filter to obtain the decolorized solution;

[0073] (8) The decolorizing solution is subjected to ultrafiltration. The pore size of the ultrafiltration membrane is 0.05 μm and the operating pressure is 0.6 bar.

[0074] (9) The solution obtained in step (8) is processed through a D851 resin column at a flow rate of 2 BV / h and the filtrate is collected.

[0075] (10) The filtrate from step (9) is subjected to electrodialysis to obtain succinic acid solution;

[0076] The operating voltage was 300V, the feed flow rate was 100L / h, the processing time was 4 hours, and the feed-to-discharge volume ratio was 1.2, resulting in succinic acid solution.

[0077] (11) Concentrate the succinic acid solution to a concentration of 100±20 g / L to obtain a concentrated solution;

[0078] (12) The concentrate in step (11) is stirred and crystallized at 50°C. Seed crystals are added and crystallized for 1 hour. The temperature is first reduced to 20°C at a rate of 1°C / h, and then gradually reduced to 10°C at a rate of 0.5°C / h. The solid and liquid are separated by vacuum filtration or centrifugation.

[0079] (13) The residual mother liquor is circulated once according to steps (11)-(12), or the circulation operation can be repeated multiple times after enough mother liquor is collected to obtain solid succinic acid.

[0080] (14) The obtained succinic acid solid was dried by hot air at 80℃ for 6 hours, and then sieved to obtain the finished product. Figure 2 As shown.

[0081] Example 2

[0082] (1) Solid-liquid separation was carried out in 1000L of fermentation broth containing L-calcium malate through a plate and frame filter press with a filter cloth pore size of 300 mesh. The initial filtrate was filtered a second time. When the filter cake was formed and the filtrate was clear, the filtrate was collected.

[0083] (2) Add 1.5% polyaluminum chloride (PAC) by weight of the filtrate obtained in step (1). The PAC flocculant is prepared in advance as a 10% aqueous solution by weight. Slowly pour it into the fermentation broth and stir at 80 rpm for 5 min. Then slowly add 80 ppm polyacrylamide (PAA) by weight. The PAC flocculant is prepared in advance as a 5‰ aqueous solution by weight. Adjust the stirring speed to 200 rpm and stir for 10 min. Then add 1.5% diatomaceous earth, stir evenly, and let stand to obtain a mixed solution.

[0084] (3) The mixture obtained in step (2) is separated into solid and liquid by a plate and frame filter press with a filter cloth pore size of 500 mesh. The initial filtrate is filtered a second time. When the filter cake is formed and the filtrate is clear, the filtrate is collected.

[0085] (4) Concentrate the filtrate from step (3) under reduced pressure to 1 / 6 of its original volume to obtain a concentrated solution;

[0086] (5) Add sulfuric acid to the concentrated solution obtained in step (4) to adjust the pH to 1.0 to obtain an acidified solution;

[0087] (6) The acidified liquid obtained in step (5) is separated into solid and liquid by a plate and frame filter press with a filter cloth pore size of 400 mesh. The initial filtrate is filtered a second time. When the filter cake is formed and the filtrate is clear, the filtrate is collected.

[0088] (7) Add activated carbon with a final mass concentration of 1% to the filtrate, decolorize at 60°C for 5 hours, and filter to obtain the decolorized solution;

[0089] (8) The decolorizing solution is subjected to ultrafiltration. The pore size of the ultrafiltration membrane is 0.05 μm and the operating pressure is 0.6 bar.

[0090] (9) The solution obtained in step (8) is processed through a D851 resin column at a flow rate of 1 BV / h and the filtrate is collected.

[0091] (10) The filtrate from step (9) is subjected to electrodialysis to obtain succinic acid solution;

[0092] The operating voltage was 200V, the feed flow rate was 150L / h, the processing time was 3 hours, and the feed-to-discharge volume ratio was 1.4, resulting in succinic acid solution.

[0093] (11) Concentrate the succinic acid solution to a concentration of 200 g / L to obtain a concentrated solution;

[0094] (12) The concentrate in step (11) is stirred and crystallized at 50°C. Seed crystals are added and crystallized for 1 hour. The temperature is first reduced to 20°C at a rate of 1°C / h, and then gradually reduced to 10°C at a rate of 0.5°C / h. The solid and liquid are separated by vacuum filtration or centrifugation.

[0095] (13) The residual mother liquor is circulated once according to steps (11)-(12), or the circulation operation can be repeated multiple times after enough mother liquor is collected to obtain solid succinic acid.

[0096] (14) The obtained succinic acid solid was dried by hot air at 80°C for 8 hours and then sieved to obtain the finished product.

[0097] Example 3

[0098] (1) Solid-liquid separation was carried out in 1000L of fermentation broth containing L-calcium malate through a plate and frame filter press with a filter cloth pore size of 300 mesh. The initial filtrate was filtered a second time. When the filter cake was formed and the filtrate was clear, the filtrate was collected.

[0099] (2) Add 1.5% polyaluminum chloride (PAC) by weight of the filtrate obtained in step (1). The PAC flocculant is prepared in advance as a 10% aqueous solution by weight. Slowly pour it into the fermentation broth and stir at 100 rpm for 5 min. Then slowly add 100 ppm polyacrylamide (PAC) by weight. The PAC flocculant is prepared in advance as a 5‰ aqueous solution by weight. Adjust the stirring speed to 200 rpm and stir for 10 min. Then add 1% diatomaceous earth, stir evenly, and let stand to obtain a mixture.

[0100] (3) The mixture obtained in step (2) is separated into solid and liquid by a plate and frame filter press with a filter cloth pore size of 400 mesh. The initial filtrate is filtered a second time. When the filter cake is formed and the filtrate is clear, the filtrate is collected.

[0101] (4) Concentrate the filtrate from step (3) under reduced pressure to 1 / 4 of its original volume to obtain a concentrated solution;

[0102] (5) Add sulfuric acid to the concentrated solution obtained in step (4) to adjust the pH to 3.0 to obtain an acidified solution;

[0103] (6) The acidified liquid obtained in step (5) is separated into solid and liquid by a plate and frame filter press with a filter cloth pore size of 400 mesh. The initial filtrate is filtered a second time. When the filter cake is formed and the filtrate is clear, the filtrate is collected.

[0104] (7) Add activated carbon with a final mass concentration of 1% to the filtrate, decolorize at 60°C for 5 hours, and filter to obtain the decolorized solution;

[0105] (8) The decolorizing solution is subjected to ultrafiltration. The pore size of the ultrafiltration membrane is 0.05 μm and the operating pressure is 0.6 bar.

[0106] (9) The solution obtained in step (8) is processed through a D851 resin column at a flow rate of 1 BV / h and the filtrate is collected.

[0107] (10) The filtrate from step (9) is subjected to electrodialysis to obtain succinic acid solution;

[0108] The operating voltage was 200V, the feed flow rate was 200L / h, the processing time was 3 hours, and the feed-to-discharge volume ratio was 1.6, resulting in succinic acid clear solution.

[0109] (11) Concentrate the succinic acid solution to a concentration of 200 g / L to obtain a concentrated solution;

[0110] (12) The concentrate in step (11) is stirred and crystallized at 50°C. Seed crystals are added and crystallized for 1 hour. The temperature is first reduced to 20°C at a rate of 1°C / h, and then gradually reduced to 10°C at a rate of 0.5°C / h. The solid and liquid are separated by vacuum filtration or centrifugation.

[0111] (13) The residual mother liquor is circulated once according to steps (11)-(12), or the circulation operation can be repeated multiple times after enough mother liquor is collected to obtain solid succinic acid.

[0112] (14) The obtained succinic acid solid was dried by hot air at 80°C for 6 hours and then sieved to obtain the finished product.

[0113] Example 4

[0114] Succinic acid was extracted according to the method of Example 3, except that in step (5), the pH was adjusted to 1.5.

[0115] Example 5

[0116] Succinic acid was extracted according to the method of Example 3, except that in step (5), the pH was adjusted to 2.

[0117] Example 6

[0118] Succinic acid was extracted according to the method of Example 3, except that in step (5), the pH was adjusted to 2.5.

[0119] Example 7

[0120] Succinic acid was extracted according to the method of Example 3, except that in step (10), the operating voltage was 250V, the feed flow rate was 150L / h, the processing time was 4 hours, and the feed-to-output volume ratio was 1.3.

[0121] Example 8

[0122] Succinic acid was extracted according to the method of Example 3, except that in step (10), the operating voltage was 200V, the feed flow rate was 100L / h, the processing time was 6 hours, and the feed-to-output volume ratio was 1.2.

[0123] Example 9

[0124] Succinic acid was extracted according to the method of Example 3, except that in step (10), the operating voltage was 250V, the feed flow rate was 200L / h, the processing time was 3 hours, and the feed-to-output volume ratio was 1.6.

[0125] Example 10

[0126] Succinic acid was extracted according to the method in Example 3, except that step (8) was omitted.

[0127] Example 11

[0128] Succinic acid was extracted according to the method in Example 3, except that step (10) was omitted.

[0129] Example 12

[0130] Succinic acid was extracted according to the method of Example 3, except that in step (7), the activated carbon was replaced with a decolorizing agent obtained by mixing activated carbon, aluminum sulfate and sodium aluminate in a mass ratio of 1:0.03:0.05.

[0131] Example 13

[0132] Succinic acid was extracted according to the method of Example 3, except that in step (7), the activated carbon was replaced with a decolorizing agent obtained by mixing activated carbon, aluminum sulfate and sodium aluminate in a mass ratio of 1:0.06:0.07.

[0133] Example 14

[0134] Succinic acid was extracted according to the method of Example 3, except that in step (7), activated carbon was replaced with a decolorizing agent obtained by mixing activated carbon, aluminum sulfate and sodium aluminate in a mass ratio of 1:0.1:0.1.

[0135] Example 15

[0136] Succinic acid was extracted according to the method of Example 3, except that in step (7), activated carbon was replaced with aluminum sulfate.

[0137] Example 16

[0138] Succinic acid was extracted according to the method of Example 3, except that in step (7), activated carbon was replaced with sodium aluminate.

[0139] Comparative Example 1

[0140] Succinic acid was extracted according to the method of Example 3, except that diatomaceous earth was not added in step (2).

[0141] Comparative Example 2

[0142] Succinic acid was extracted according to the method in Example 3, except that polyacrylamide was not added in step (2).

[0143] Comparative Example 3

[0144] Succinic acid was extracted according to the method of Example 3, except that polyaluminum chloride was not added in step (2).

[0145] Comparative Example 4

[0146] Succinic acid was extracted according to the method in Example 3, except that step (1) was omitted.

[0147] Test case

[0148] The parameters of the succinic acid obtained in the examples and comparative examples are shown in Table 1; the purity was measured by HPLC. The HPLC chromatograms are shown below. Figure 1 As shown, the saturated solubility of succinic acid at room temperature is 7% by mass, and the elution time of succinic acid is 11.56 min.

[0149] Succinic acid weight determination:

[0150] Weigh the dried succinic acid product using an analytical balance and accurately record its quality.

[0151] Purity determination:

[0152] Weigh 0.01g of succinic acid sample into a 10mL volumetric flask, dilute to the 10mL mark with ultrapure water, filter the dissolved sample through a 0.22μm pore size aqueous filter membrane and place it into a liquid chromatography vial. Analyze the content of malic acid, succinic acid and fumaric acid in the sample using HPLC, and calculate the percentage of succinic acid, which is the purity of succinic acid.

[0153] Sulfate content:

[0154] Accurately weigh 2g of succinic acid sample into a 10mL volumetric flask, and dilute to the 10mL mark with ultrapure water. The SO42- content in the solution... 2- Concentration was determined using the polyvinyl alcohol-turbidimetric method. A precise amount of SO4 was accurately pipetted. 2- The standard solution was placed in a 25 mL colorimetric tube, and 2.5 mL of a 1:1 hydrochloric acid aqueous solution and 2.5 mL of anhydrous ethanol were added sequentially. Then, 5 mL of polyvinyl alcohol and barium chloride solution were added, and the volume was adjusted to 25 mL with deionized water. The solution was shaken for 30 s, and after stabilization, the absorbance of the solution was measured. Based on the experimental results, a method for establishing SO42- standard solutions was developed. 2- A linear standard curve of concentration versus absorbance was established. The absorbance of the test solution was measured using a UV spectrophotometer (Shanghai Yuan Instrument Co., Ltd., UV-8000A) according to the above method. Substituting the absorbance values ​​into the standard curve, the SO4 concentration in the test solution could be calculated. 2- Concentration, and according to SO42- Concentration calculation of sulfate content.

[0155] Determination of residue on ignition:

[0156] Accurately weigh 2g of sample and add it to a constant-weight crucible. Accurately weigh the sample and ignite it until fully carbonized. Cool the sample and add 0.5-1.0mL of sulfuric acid. Heat the sample until the sulfuric acid vapor is removed and ignite it at 700-800℃ until completely ashed. Then place the sample in a desiccator to cool to room temperature, accurately measure its weight, and calculate the content of its ignition residue.

[0157] Succinic acid recovery rate determination:

[0158]

[0159] In the formula, M is the weight of succinic acid (g), C is the concentration of succinic acid in the L-calcium malate fermentation broth (g / L), and V is the volume of the L-calcium malate fermentation broth (L).

[0160] Table 1

[0161] Succinic acid weight / g purity / % Sulfate content / % Residue on ignition / % Recovery rate / % Example 1 8784 98.2 0.1 0.3 73.2 Example 2 9756 98.8 0.1 0.2 81.3 Example 3 8160 97.5 0.15 0.4 68.0 Example 4 8520 98.4 0.15 0.24 71.0 Example 5 8748 98.5 0.1 0.26 72.9 Example 6 8256 98.0 0.15 0.32 68.8 Example 7 8700 98.5 0.01 0.16 72.5 Example 8 8412 98.1 0.08 0.15 70.1 Example 9 8052 97.7 0.12 0.25 67.1 Example 10 7572 97.03 0.18 0.42 63.1 Example 11 7488 97.08 0.2 0.45 62.4 Example 12 8580 98.3 0.1 0.35 71.5 Example 13 8616 98.5 0.0.8 0.32 71.8 Example 14 8712 98.6 0.07 0.28 72.6 Example 15 8304 98.1 0.12 0.39 69.2 Example 16 8352 98.2 0.13 0.37 69.6 Comparative Example 1 7056 96.65 0.23 0.53 58.8 Comparative Example 2 6960 96.39 0.25 0.58 58.6 Comparative Example 3 6744 96.18 0.22 0.62 56.2 Comparative Example 4 6048 96.64 0.22 0.57 50.4

[0162] As can be seen from the results in Table 1, the weight, purity, and recovery rate of succinic acid extracted in Examples 1-16 are higher than those in Comparative Examples 1-4. The sulfate content and ignition residue of the succinic acid obtained in Examples 1-16 are lower than those in Comparative Examples 1-4, indicating that the method provided by the present invention can effectively improve the yield and purity of succinic acid.

[0163] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for extracting succinic acid from malic acid fermentation broth, characterized in that, Includes the following steps: (1) Separate the fermentation broth into solid and liquid phases I and collect the liquid phase I; (2) After mixing the liquid phase I with polyaluminum chloride, polyacrylamide and diatomaceous earth and allowing it to stand, perform solid-liquid separation II and concentration, and collect the concentrated liquid; (3) After adjusting the pH of the concentrated solution to 1-3, an acidified solution is obtained; (4) The acidified liquid is separated into solid and liquid phases (III) to obtain liquid phase (II); (5) The liquid phase II and the decolorizing agent are mixed for decolorization, and the solid-liquid separation IV is performed to obtain the decolorized liquid. The decolorized liquid is subjected to ultrafiltration, ion exchange adsorption, electrodialysis and crystallization to obtain succinic acid.

2. The method according to claim 1, characterized in that, In step (2), the total amount of the polymeric alumina, the polyacrylamide and the diatomaceous earth added is 2-4g relative to 100g of the liquid phase I.

3. The method according to claim 2, characterized in that, The mass ratio of the polyaluminum chloride, the polyacrylamide, and the diatomaceous earth is 10:0.005-0.02:10-30.

4. The method according to any one of claims 1 to 3, characterized in that, In step (2), the concentration step includes concentrating the liquid obtained from the solid-liquid separation II to 1 / 6 to 1 / 4 of its original volume.

5. The method according to any one of claims 1 to 3, characterized in that, The decolorizing agent contains activated carbon, aluminum sulfate, and sodium aluminate; The mass ratio of the activated carbon, the aluminum sulfate, and the sodium aluminate is 1:0.03-0.1:0.05-0.

1.

6. The method according to any one of claims 1 to 3, characterized in that, The conditions for ultrafiltration include at least the following: filter pore size less than or equal to 0.05 μm and pressure of 0.6-1.5 bar.

7. The method according to any one of claims 1 to 3, characterized in that, The membrane used in the electrodialysis is a homogeneous polyethylene ion exchange membrane. The conditions for the electrodialysis include at least the following: voltage 200-300V, feed flow rate 100-200L / h, time 3-6h, and feed-to-output volume ratio 1.2-1.6:

1.

8. The method according to any one of claims 1 to 3, characterized in that, The crystallization process includes concentration and cooling crystallization; The cooling crystallization method includes: stirring and crystallizing at a temperature of 45-55℃, and then adding seed crystals to grow crystals.

9. The method according to any one of claims 1 to 3, characterized in that, The solid-liquid separation I, the solid-liquid separation II, and the solid-liquid separation III are plate and frame filters, and the filter cloth pore size of the plate and frame filter is less than or equal to 48 μm.

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