Method and device for preparing succinic acid from succinate fermentation liquor

Abstract

The invention relates to a method for extracting succinic acid from succinate fermentation liquor by using a resin and membrane method, and belongs to the technical field of biochemical engineering. The method comprises the following steps: by taking fermentation liquor added with magnesium carbonate as a neutralizing agent as a preparation raw material, separating by using an inorganic membrane to remove insoluble substances and macromolecular proteins, then carrying out decoloration and concentration treatment by using an organic membrane, then converting magnesium succinate into sodium succinate by using resin, and carrying out evaporative crystallization treatment on the obtained sodium succinate and a small part of succinic acid, thereby obtaining the magnesium succinate sodium succinate. Carrying out sodium removal treatment on the evaporation mother liquor by adopting a bipolar membrane, and continuously carrying out evaporative crystallization on the obtained original chamber liquid to obtain the high-purity succinic acid crystal. The production of solid waste and the adsorption of succinic acid by activated carbon are avoided, not only is the extraction rate improved, but also the follow-up treatment water quantity is reduced, the continuous ion exchange device realizes the continuity of adsorption and desorption of succinate, part of succinic acid can be separated out in advance through evaporative crystallization, follow-up evaporation mother liquor enters a bipolar membrane, and the treatment capacity of the bipolar membrane is reduced.

Description

Technical Field

[0001] The invention relates to a method and a device for preparing succinic acid from succinate fermentation liquid, belonging to the technical field of biochemical engineering. Background Art

[0002] Succinic acid is also known as succinic acid because it was obtained from distilled amber in 1550. Its molecular formula is C4H6O4, molecular weight is 118.08, melting point is 185℃, solubility of succinic acid in water is 100mg / ml at 20℃, slightly soluble in ethanol, ether, acetone, glycerol, pure succinic acid is colorless or white crystal, sour, odorless. As an intermediate product of tricarboxylic acid cycle and also the final metabolic product of some anaerobic microorganisms, succinic acid ranks first among the 12 important "construction intermediates" of industrial microbial transformation, and is an important platform compound for the synthesis of bulk high value-added chemicals, with huge economic value. In the pharmaceutical industry, succinic acid can be used to prepare hemostatic agents, antidotes and diuretics and is widely used as a drug intermediate; in agriculture, processed succinic acid can be used to increase the germination rate of seeds, promote the growth of crops, and can also be used as an additive for herbicides and feed additives for monogastric animals; in the chemical industry, succinic acid can be used to synthesize some high-performance polymer materials and can also be used to synthesize biodegradable plastics. At present, the production methods of succinic acid include chemical synthesis, biotransformation and biofermentation, but the raw materials of the chemical synthesis method are non-renewable petrochemical products, and the process is energy-intensive and highly polluting, which does not meet the requirements of sustainable development. The substrate used in the biotransformation method is relatively expensive, so it is difficult to industrialize. The biofermentation method has become the mainstream process due to its easy availability of substrates, low price and environmentally friendly process. However, since inorganic salts such as magnesium carbonate need to be added during the fermentation process, most of the fermentation broth obtained is succinate, which needs to be converted later.

[0003] The existing purification methods are mainly divided into (1) precipitation method: using calcium salt, zinc salt and ammonium salt to precipitate succinic acid, then acidolyzing with sulfuric acid, and then decolorizing with activated carbon to finally obtain succinic acid, but the process consumes a lot of chemical raw materials and the recovery cost is high; (2) two-phase method: a system formed by organic solvent, inorganic salt and water at appropriate concentrations. At this time, the salt does not precipitate, but the liquid-liquid stratification forms two phases. After the fermentation liquid is acidified, an acid salt with a large solubility and a hydrophilic organic solvent are added to form a two-phase aqueous system. The separation is subtracted. The solvent is recovered by high-pressure distillation, the mother liquor is decolorized with activated carbon, and the succinic acid product is obtained by concentration and crystallization. The lower phase is recovered with hydrophilic alcohol. However, this method has the disadvantages of low yield and inability to remove impure acids. (3) Complex extraction method: different tertiary amine extractants are used to extract succinic acid in different diluents. It is found that the yield and purity of succinic acid with different extractants are different. However, the extraction process requires a large amount of reagents and has high requirements for stripping agents. Therefore, it is urgent to combine processes to achieve the conversion of succinate in the fermentation broth. Summary of the invention

[0004] In order to solve the problems of complicated purification steps and poor treatment effect of succinate fermentation broth in the prior art, a method and device for preparing succinic acid from succinate fermentation broth are provided.

[0005] The technical solution is:

[0006] A method for preparing succinic acid from a succinate fermentation broth comprises the following steps:

[0007] The fermentation broth containing succinate is filtered and impurities are removed by using a ceramic membrane;

[0008] The filtrate from the ceramic membrane is filtered and decolorized using an ultrafiltration membrane;

[0009] The permeate of the ceramic membrane is treated with sodium-type ion exchange resin to exchange Mg 2+ Convert to Na + ;

[0010] The permeate of the sodium-type ion exchange resin is concentrated and then subjected to bipolar membrane electrodialysis to obtain an alkaline solution and a sodium-removed succinic acid solution.

[0011] The fermentation liquid containing succinate is obtained by preparing succinic acid by a fermentation method using magnesium carbonate as a neutralizing agent.

[0012] The pore size of the ceramic membrane is in the range of 20-200 nm, the operating pressure is in the range of 0.1-1 MPa, and the pH is in the range of 0-14.

[0013] The molecular weight cut-off range of the ultrafiltration membrane is 3000-5000Da, the operating pressure is 0.5-1MPa, the operating temperature is 5-45°C, and the pH range is 3-10.

[0014] The concentration process uses nanofiltration membrane concentration, the nanofiltration membrane has a molecular weight cutoff between 300-550Da, an operating pressure of 0.7-2.5MPa, an operating temperature of 5-45°C, and a pH range of 3-10.

[0015] During the bipolar membrane electrodialysis process, the current density is maintained at 400-800A / m 2 .

[0016] A device for preparing succinic acid from succinate fermentation broth, comprising:

[0017] Ceramic membrane 1, used for filtering and removing impurities from succinate fermentation broth;

[0018] The ultrafiltration membrane 2 is connected to the permeation side of the ceramic membrane 1 and is used to filter and decolorize the filtrate of the ceramic membrane 1;

[0019] The sodium type ion exchange resin 3 is connected to the permeation side of the ultrafiltration membrane 2 and is used to perform ion exchange treatment on the permeate of the ultrafiltration membrane 2 to convert Mg 2+ Convert to Na + ;

[0020] The nanofiltration membrane 4 is connected to the liquid outlet of the sodium-type ion exchange resin 3 and is used to concentrate the liquid outlet of the sodium-type ion exchange resin 3;

[0021] The bipolar membrane electrodialyzer 5 is used to perform bipolar membrane electrodialysis treatment on the concentrated liquid of the nanofiltration membrane 4 to obtain alkaline solution and a sodium-removed succinic acid solution.

[0022] The pore size range of the ceramic membrane is 200-200nm.

[0023] The molecular weight cut-off of the ultrafiltration membrane is between 3000-5000Da.

[0024] The molecular weight cut-off of the nanofiltration membrane is between 300-550Da.

[0025] The bipolar membrane electrodialyzer 4 is connected to an alkali solution storage tank, and the alkali solution storage tank is used to receive the alkali solution obtained by removing sodium through electrodialysis treatment.

[0026] Beneficial Effects

[0027] The present invention provides a method for extracting succinic acid from succinate fermentation broth using a resin + membrane method. The entire conversion process can be roughly divided into the following steps: after the fermentation broth is heated, a ceramic membrane is used to filter and remove protein, part of the fermentation bacteria and insoluble substances in the fermentation broth; the ceramic membrane clear liquid is passed through an organic membrane to remove pigments and macromolecular proteins and then concentrated; the concentrated concentrated liquid is subjected to continuous exchange resin to replace calcium and magnesium ions; since a small amount of succinic acid is also present in the fermentation broth, the sodium succinate after the resin is mixed with a small amount of succinic acid solution for evaporation and crystallization to obtain pure succinic acid crystals and mother liquor; the mother liquor is then used to prepare high-purity succinic acid using a bipolar membrane, and then crystallization is performed; the crystallized mother liquor after crystallization can be returned to the bipolar membrane part for further extraction. It is known that in the existing process, most of the coarse filtration processes involve plate and frame or centrifugation. Ceramic membranes have high precision, high temperature resistance and high economy, and can achieve continuous operation. Organic membrane decolorization and concentration, this step reduces the processing volume for subsequent bipolar membrane and evaporation crystallization treatment, and avoids the use of activated carbon for decolorization, reducing solid waste generation. Continuous ionization resin can continuously convert succinate in the ceramic membrane clear liquid into sodium succinate, and can achieve simultaneous adsorption and analysis. The use of bipolar membranes to produce organic acids is green and environmentally friendly, and the by-products can be reused. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is the flow chart of this patent;

[0029] Figure 2 It is the device diagram of this patent.

[0030] Among them, 1. Ceramic membrane; 2. Ultrafiltration membrane; 3. Sodium-type ion exchange resin; 4. Nanofiltration membrane; 5. Bipolar membrane electrodialyzer. DETAILED DESCRIPTION

[0031] The present invention uses fermentation liquid with magnesium carbonate added as a neutralizer as a preparation raw material, removes insoluble substances and macromolecular proteins through inorganic membrane separation, and then uses organic membrane for decolorization and concentration treatment, and then uses resin to convert magnesium succinate into sodium succinate, and uses evaporation and crystallization treatment to obtain part of succinic acid crystals and evaporation mother liquor, and uses bipolar membrane to remove sodium from the evaporation mother liquor, and the obtained original chamber liquid continues to evaporate and crystallize to obtain high-purity succinic acid crystals. The turbidity of the fermentation liquid treated with ceramic membrane is reduced to 1NTU, and the yield can reach more than 85%. The decolorization effect of organic membrane is equivalent to that of activated carbon, but the generation of solid waste and the adsorption of activated carbon to succinic acid are avoided. The concentration multiple of nanofiltration membrane can reach more than 5 times, which not only improves the extraction rate and reduces the amount of subsequent treatment water, the continuous separation and exchange device realizes the continuity of adsorption and analysis of succinate, evaporation and crystallization can allow part of succinic acid to precipitate first, and the subsequent evaporation mother liquor enters the bipolar membrane, reducing the bipolar membrane processing amount, and the bipolar membrane extraction process of succinic acid is green and environmentally friendly, and the by-products can be reused.

[0032] In some embodiments, the method of the present invention is implemented by the following steps:

[0033] 1. A method for extracting succinic acid from succinate fermentation broth by resin + membrane method, which is characterized in that the fermentation broth with magnesium carbonate as a neutralizer is used as a raw material, after impurity removal, decolorization and concentration by inorganic membrane and organic membrane, the resin is used to convert the salt, and then part of the succinic acid is evaporated and crystallized, and the mother liquor is then passed through a bipolar membrane to prepare succinic acid, and the steps are as follows:

[0034] (1) Fermentation broth separation: The succinate fermentation broth was subjected to a decontamination experiment by passing it through a ceramic membrane to remove the fermentation bacteria and some insoluble substances. A 50 nm ceramic membrane was used with an operating pressure of 0.1-1 MPa, an operating temperature of 20-80 degrees Celsius, and a pH range of 0-14 to obtain a clear and transparent liquid.

[0035] (2) Organic membrane was used for decolorization and concentration experiment, ultrafiltration membrane was used for decolorization, pigments and some macromolecular proteins were retained in the concentrated solution, and the target product was recovered as much as possible by adding washing water in the later stage of the experiment. The molecular weight cutoff of ultrafiltration membrane was between 3000-5000Da, the operating pressure was 0.5-1MPa, the operating temperature was 5-45℃, and the pH range was 3-10. Nanofiltration membrane was used for concentration, and the concentration was 4-10 times. The molecular weight cutoff of nanofiltration membrane was between 300-550Da, the operating pressure was 0.7-2.5MPa, the operating temperature was 5-45℃, and the pH range was 3-10.

[0036] (3) Continuous ion exchange resin is used to convert succinic acid to convert succinate into sodium succinate. The resin used in this step is a hardness removal resin. The adsorption and analysis synchronization can be achieved by setting up a continuous ion exchange device, which is divided into an adsorption zone and a regeneration zone. The resin type is Zhengguang D860, and 2%-4% NaOH and 2%-4% HCl are configured in the analysis process.

[0037] (4) After resin adsorption, the solution is evaporated and crystallized to obtain succinic acid crystals and evaporated mother liquor. The mother liquor is converted into succinic acid using a bipolar membrane, and sodium succinate is converted into succinic acid. The final solution in the original chamber is further evaporated and crystallized to obtain as much pure succinic acid as possible. The bipolar membrane uses a two-chamber bipolar membrane, and the current density is maintained at 400-800A / m during the process. 2 The succinic acid content of the film can eventually reach 15-20%.

[0038] Based on the above process, the device structure used in this patent is as follows Figure 2 As shown, including:

[0039] Ceramic membrane 1, used for filtering and removing impurities from succinate fermentation broth;

[0040] The ultrafiltration membrane 2 is connected to the permeation side of the ceramic membrane 1 and is used to filter and decolorize the filtrate of the ceramic membrane 1;

[0041] The sodium type ion exchange resin 3 is connected to the permeation side of the ultrafiltration membrane 2 and is used to perform ion exchange treatment on the permeate of the ultrafiltration membrane 2 to convert Mg 2+ Convert to Na + ;

[0042] The nanofiltration membrane 4 is connected to the liquid outlet of the sodium-type ion exchange resin 3 and is used to concentrate the liquid outlet of the sodium-type ion exchange resin 3;

[0043] The bipolar membrane electrodialyzer 5 is used to perform bipolar membrane electrodialysis treatment on the concentrated liquid of the nanofiltration membrane 4 to obtain alkaline solution and a sodium-removed succinic acid solution.

[0044] The pore size range of the ceramic membrane is 200-200nm.

[0045] The molecular weight cut-off of the ultrafiltration membrane is between 3000-5000Da.

[0046] The molecular weight cut-off of the nanofiltration membrane is between 300-550Da.

[0047] The bipolar membrane electrodialyzer 4 is connected to an alkali solution storage tank, and the alkali solution storage tank is used to receive the alkali solution obtained by removing sodium through electrodialysis treatment.

[0048] Example 1

[0049] The ceramic membrane experiment was carried out with 40 kg of fermentation liquid. The content of succinate (mainly magnesium succinate including a part of succinic acid) in the fermentation liquid was about 8.51 g / L. The fermentation stock liquid was clarified and impurities were removed using a 50 nm ceramic membrane. The inlet pressure was set to 0.2 MPa, the outlet pressure was 0.1 MPa, and the reflux was maintained at 3-4 m 3 / L, 10kg of washing water was added during the process, and finally 41.5kg of ceramic membrane clear liquid was obtained. The average flux of ceramic membrane filtration was 120LMH. At this time, the succinate content was 7.51g / L. The ceramic membrane clear liquid was decolorized using an ultrafiltration membrane with a molecular weight cutoff of 4000. The experimental feed was 41kg, the pressure was set to 0.7MPa, and the reflux was maintained at 1-2m 3 / L, 10kg of washing water was added during the process, and 42.8kg of ultrafiltration clear liquid was finally obtained, with an average flux of 18.2LMH and a succinate content of 6.14g / L. The clear liquid was subsequently concentrated by a nanofiltration membrane with a molecular weight cutoff of 400Da. 42kg of feed was fed and 33.5kg of clear liquid was finally discharged, which was concentrated 4.9 times. At this time, the succinate content was 25.8g / L. The concentrated liquid was passed through a sodium-type ion exchange resin and a continuous ion exchange resin was used to remove hard resins, which was divided into an adsorption zone, a water top zone and a decomposition zone. The flow rate was controlled at 2BV. After passing through the resin, the content of succinate (mainly sodium succinate including a part of succinic acid) was 22.5g / L. At this time, the content of calcium and magnesium ions had been reduced to 5ppm, which met the bipolar membrane inlet water requirements. The bipolar membrane voltage was set to 25V and the current was maintained at 4.4A. After bipolar membrane extraction, the concentration of pure succinic acid was about 21.3g / L, and the concentration of the obtained alkali solution was about 2mol / L. The alkali solution can be used to adjust the pH in fermentation and can also be used for acid-base regeneration in continuous deionization.

[0050] Example 2

[0051] The ceramic membrane experiment was carried out with 60 kg of fermentation liquid. The succinate content in the fermentation liquid was about 10.2 g / L. The fermentation liquid was clarified and impurities were removed using a 50 nm ceramic membrane. The inlet pressure was set to 0.24 MPa, the outlet pressure was 0.12 MPa, and the reflux was maintained at 3.5 m 3 / L, 10kg of washing water was added during the process, and finally 58.4kg of ceramic membrane clear liquid was obtained. The average flux of ceramic membrane filtration was 135LMH. At this time, the succinate content was 9.21g / L. The ceramic membrane clear liquid was decolorized using an ultrafiltration membrane with a molecular weight cutoff of 4000. The experimental feed was 58kg, the pressure was set to 0.8MPa, and the reflux was maintained at 1.2m 3 / L, 5kg of washing water was added during the process, and finally 54.5kg of ultrafiltration clear liquid was obtained, with an average flux of 17.6LMH and a succinate content of 8.55g / L. The clear liquid was subsequently concentrated by a nanofiltration membrane with a molecular weight cutoff of 400Da. 54kg of feed was fed and 44kg of clear liquid was finally discharged, which was concentrated 5.4 times. At this time, the succinate content was 39.8g / L. The concentrated liquid was passed through the resin and continuous ion exchange was used to remove the hard resin, which was divided into an adsorption zone, a water top zone and a decomposition zone. The flow rate was controlled at 2BV, after passing through the resin, the content of succinate (mainly sodium succinate including a part of succinic acid) is 37.4g / L, at this time, the content of calcium and magnesium ions has been reduced to 5ppm, which meets the bipolar membrane water inlet requirements, the bipolar membrane voltage is set to 25V, and the current is maintained at 4.4A. After bipolar membrane extraction, the concentration of pure succinic acid is about 36.8g / L, and the concentration of the obtained alkali solution is about 2mol / L. The alkali solution can be used to adjust the pH in fermentation and can also be used for acid-base regeneration in continuous desorption.

Claims

1. A method for preparing succinic acid from succinate fermentation broth, characterized in that: The steps include: The fermentation broth containing succinate is filtered and impurities are removed by using a ceramic membrane; The filtrate from the ceramic membrane is filtered and decolorized using an ultrafiltration membrane; The permeate of the ceramic membrane is treated with sodium-type ion exchange resin to exchange Mg 2+ Convert to Na + ; The permeate of the sodium-type ion exchange resin is concentrated and then subjected to bipolar membrane electrodialysis to obtain an alkaline solution and a sodium-removed succinic acid solution.

2. The method for preparing succinic acid from succinate fermentation broth according to claim 1, characterized in that: The fermentation liquid containing succinate is obtained by preparing succinic acid by a fermentation method using magnesium carbonate as a neutralizing agent.

3. The method for preparing succinic acid from succinate fermentation broth according to claim 1, characterized in that: The pore size of the ceramic membrane is in the range of 20-200 nm, the operating pressure is in the range of 0.1-1 MPa, and the pH is in the range of 0-14.

4. The method for preparing succinic acid from succinate fermentation broth according to claim 1, characterized in that: The molecular weight cut-off range of the ultrafiltration membrane is 3000-5000Da, the operating pressure is 0.5-1MPa, the operating temperature is 5-45°C, and the pH range is 3-10.

5. The method for preparing succinic acid from succinate fermentation broth according to claim 1, characterized in that: The concentration process uses nanofiltration membrane concentration, the nanofiltration membrane has a molecular weight cutoff between 300-550Da, an operating pressure of 0.7-2.5MPa, an operating temperature of 5-45°C, and a pH range of 3-10.

6. The method for preparing succinic acid from succinate fermentation broth according to claim 1, characterized in that: During the bipolar membrane electrodialysis process, the current density is maintained at 400-800A / m 2 .

7. A device for preparing succinic acid from succinate fermentation broth, characterized in that: include: A ceramic membrane (1) is used for filtering and removing impurities from the succinate fermentation broth; An ultrafiltration membrane (2) is connected to the permeation side of the ceramic membrane (1) and is used to filter and decolorize the filtrate of the ceramic membrane (1); The sodium type ion exchange resin (3) is connected to the permeation side of the ultrafiltration membrane (2) and is used to perform ion exchange treatment on the permeate of the ultrafiltration membrane (2) to convert Mg 2+ Convert to Na + ; A nanofiltration membrane (4) is connected to the liquid outlet of the sodium-type ion exchange resin (3) and is used to concentrate the liquid outlet of the sodium-type ion exchange resin (3); The bipolar membrane electrodialyzer (5) is used to perform bipolar membrane electrodialysis treatment on the concentrated liquid of the nanofiltration membrane (4) to obtain an alkaline solution and a sodium-removed succinic acid solution.

8. The device for preparing succinic acid from succinate fermentation broth according to claim 7, characterized in that: The pore size range of the ceramic membrane is 200-200nm.

9. The device for preparing succinic acid from succinate fermentation broth according to claim 7, characterized in that: The molecular weight cut-off of the ultrafiltration membrane is between 3000-5000Da.

10. The device for preparing succinic acid from succinate fermentation broth according to claim 7, characterized in that: The molecular weight cutoff of the nanofiltration membrane is between 300-550Da; the bipolar membrane electrodialyzer (4) is connected to an alkali solution storage tank, and the alkali solution storage tank is used to receive the alkali solution obtained by removing sodium through electrodialysis treatment.

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