A high-efficiency extraction and purification method of L-threonine fermentation broth
By combining low-temperature centrifugation, ceramic membrane filtration, and electrodialysis with an automated drying process, the problems of complex L-threonine fermentation broth preparation and uneven heat distribution were solved, achieving efficient extraction and purification, improving purity and drying quality, and reducing energy consumption.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HEBEI RUNYUAN BIOTECHNOLOGY CO LTD
- Filing Date
- 2026-05-09
- Publication Date
- 2026-07-10
AI Technical Summary
The preparation process of L-threonine fermentation broth is complex and difficult to control, affecting purity and quality. Furthermore, uneven heat distribution during crystal heating and drying affects the quality of drying and molding, and the equipment is costly and energy-intensive.
It employs a low-temperature centrifugal separation, ceramic membrane filtration, electrodialysis desalination, pH-controlled crystallization, and automated drying mechanism, including spiral tube heating, gear meshing transmission, and elastic airbag buffer, to achieve uniform heating and drying.
It improves the purity and crystal quality of L-threonine, reduces ash content, increases recovery rate and crystal uniformity, reduces energy consumption, and enhances drying and molding quality and equipment efficiency.
Smart Images
Figure CN122355847A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of amino acid processing and extraction technology, specifically relating to a highly efficient extraction and purification method for L-threonine fermentation broth. Background Technology
[0002] L-Threonine is an essential amino acid, chemically known as α-amino-β-hydroxybutyric acid. This amino acid has applications in the food, pharmaceutical, and feed industries, promoting animal growth and development and maintaining cell membrane function. L-Threonine exists in four stereoisomers, only the L-form possessing biological activity. L-Threonine is a white crystalline powder with a melting point of 255–257°C. It is readily soluble in water but insoluble in ethanol, ether, and chloroform. Industrial production primarily employs microbial fermentation, using glucose or corn starch as raw materials and utilizing strains such as *Bacillus flavus* and *Corynebacterium glutamicum*.
[0003] The core of efficient extraction and purification of L-threonine fermentation broth is sterilization and impurity removal → desalting and concentration → isoelectric crystallization → resolution and purification → drying and packaging. The mainstream industrial process adopts a combination of "membrane separation + isoelectric point crystallization + ion exchange / electrodialysis".
[0004] The preparation process of L-threonine fermentation broth is relatively complex and difficult to control, which can easily affect the purity, color and quality of L-threonine. At the same time, if the crystals cannot make sufficient and effective uniform contact with heat during the heating and drying process, it will directly affect the quality of subsequent drying and molding, which will be detrimental to subsequent quality inspection. In addition, the drying equipment is generally equipped with a corresponding sensor temperature control system, which has a high design cost and high energy consumption, which is not conducive to saving resources and protecting the environment. Summary of the Invention
[0005] The purpose of this invention is to provide a highly efficient extraction and purification method for L-threonine fermentation broth, in order to solve the technical problems of complex preparation processes that are difficult to control and can easily affect the purity and quality of L-threonine. In addition, during the heating and drying process of crystals, the centrifuged L-threonine cannot make sufficient and effective uniform contact with heat, which directly affects the subsequent drying and molding quality.
[0006] To achieve the above objectives, the present invention adopts the following technical solution: A highly efficient method for the extraction and purification of L-threonine fermentation broth includes the following steps: S1. Cool the L-threonine fermentation broth to 20-25°C, and separate the fermentation broth by centrifuging at 3000-3500 rpm to obtain clear liquid and wet crystals respectively. S2. The clarified liquid is heated to 60°C through a heat exchanger. The clarified liquid is then filtered through a ceramic membrane with a pore size of 0.02μm. When the volume of the remaining clarified liquid is one-third of the original clarified liquid volume, dialysis water is added. The amount of dialysis water added is 15-30% of the fermentation liquid volume. The ratio of the volume of the ceramic membrane filtrate to the volume of the clarified liquid is 1:7-10. The ceramic membrane filtrate with an L-threonine content of 5g / L or higher is collected. S3. The ceramic membrane filtrate from step S2 is fed into an electrodialysis unit. Under a DC electric field, inorganic salts are removed by permeating the ion-exchange membrane. After desalting, the clear liquid is evaporated and concentrated to a concentration of 150-220 g / L. S4. After concentration, the pH of the clear liquid is adjusted to 5.1-6.0 with HCl. The temperature is controlled to 20 degrees Celsius by cooling it down by 5 degrees Celsius per hour. Crystallization is carried out for 8-12 hours to form uniform large-particle crystals. S5. After heating the crystals in step S4, dissolve them in pure water at 60°C with a weight of one-third that of the crystals, and add 0.5-1% activated carbon by weight of the crystals. Decolorize for 30-60 minutes. S6. The crystal slurry obtained in step S5 is cooled to 30-40°C in a crystallization tank and centrifuged. Washing water is gradually added during the centrifugation process. The resulting wet crystals have a moisture content of 12%. The centrifuged wet crystals are then sent to a drying unit for drying until the moisture content is <0.5%.
[0007] Furthermore, the drying processing mechanism includes a processing box with a conical opening. A spiral tube connected to the conical opening is installed on the top of the inner wall of the processing box. The bottom of the spiral tube extends downward, and there are equidistant openings along the length of the bottom of the spiral tube. A panel is fixedly connected to the inner wall of the processing box by a bracket. A support frame placed below the spiral tube is connected to both sides of the top of the panel by a first spring.
[0008] Furthermore, the top of the support frame is provided with a slot that matches it, and both ends of the support frame are telescopically connected with movable parts. A lifting column is fixedly installed at the center of the bottom of the support frame. The bottom of the lifting column passes through the panel and extends to the rotating rod. The panel is provided with a movable hole for connecting with the lifting column. A cam groove is provided on the outer edge of the lifting column. The outer wall of the cam groove movably abuts against the protrusion of the inner wall of the rotating rod. The bottom of the rotating rod is connected to the inner wall of the processing box through a bearing.
[0009] Furthermore, a first bevel gear is fixedly installed on the rotating rod, and a second bevel gear fixed on the movable shaft is meshed with both ends of the outer wall of the first bevel gear. One end of the movable shaft passes through the cover and extends to the turntable. The protrusion on the turntable and the baffle are connected by a swing rod. The baffle has a limit groove along the height direction of the side wall of the processing box.
[0010] Furthermore, both ends of the swing rod are mounted on the turntable and the baffle plate by a rotatable connection. One end of the cover is mounted on the side wall of the processing box by a first fixing rod. A ventilation hole is formed between the baffle plate and the limiting groove on the inner wall of the processing box. Bending rods are fixedly installed on both sides of the bottom end of the bearing frame. One end of the bending rod is connected to a first gear plate extending into the housing. The outer wall of the first gear plate is driven by a rotating gear to a horizontally distributed second gear plate. One end of the second gear plate penetrates the housing and extends to the movable part of the bearing frame.
[0011] Furthermore, the second gear plate and the movable part are connected by a telescopic rod, one end of the housing is connected to the side wall of the processing box by a second fixed rod, the support frame and the panel are connected by an elastic airbag, one end of the air hole on the elastic airbag is connected to a vertically distributed telescopic tube through a first conduit, the outer wall extension end of the telescopic tube is equipped with a second conduit, and the outer wall edge of the second conduit is provided with an annular opening placed on the support frame.
[0012] Furthermore, the inner walls of the first conduit and the second conduit are slidably connected with a first sealing plug and a second sealing plug, respectively. One end of the second sealing plug is connected to a spreading plate via a push rod, and the other end is connected to the inner wall of the second conduit via a second spring. An active cavity is formed between the spreading plate and the support frame.
[0013] Furthermore, both ends of the spiral tube are fixedly connected to the side wall of the processing box via crossbeams, and a heater adapted to it is detachably and fixedly installed on the inner wall of the processing box.
[0014] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: (1) This invention first performs low-temperature centrifugation on L-threonine fermentation broth, then performs ceramic membrane filtration and adds dialysis water for washing and filtration treatment, which can effectively remove cell fragments, suspended particles and macromolecular impurities, while reducing the loss of L-threonine in the membrane retentate phase, thereby improving the recovery rate of the target product. Electrodialysis desalination of the membrane filtrate can effectively remove inorganic salt impurities in the fermentation broth, reduce ash content, and reduce the adverse effects of salt on the subsequent concentration and crystallization process, thereby improving the purity and quality of L-threonine crystals. Adjusting the concentrate to a specific pH range and using controlled cooling rate and crystal growth time for crystallization can promote uniform growth of L-threonine crystals, reduce the generation of small crystals, and obtain crystals with larger particle size and more uniform distribution, thereby improving the subsequent centrifugation and washing effects.
[0015] (2) A drying mechanism is set up. Through automated temperature control, L-threonine crystals can be effectively and uniformly dried. During the fall of the spiral tube, the L-threonine crystals are heated evenly by the heater inside the processing box. The opening at the bottom of the spiral tube facilitates the entry of heat into the spiral tube for heating and drying, and also facilitates the uniform distribution of L-threonine crystals in the carrying frame. When the L-threonine crystals enter the carrying frame, the carrying frame moves downward on the first spring due to its own gravity. With the help of gear meshing, the second gear plate drives the movable parts at both ends of the carrying frame to move outward, thereby expanding the carrying area. At the same time, during the compression of the elastic airbag driven by the carrying frame, the elastic airbag provides a corresponding buffering effect and can also drive the gas to move the first sealing plug towards the telescopic tube. The setting of the telescopic tube facilitates the normal up and down movement of the carrying frame and can also further push the second sealing plug outward through compression. The second sealing plug drives the spreading plate to move synchronously in the carrying frame. Through the pushing and spreading action, L-threonine is evenly spread on the carrying frame for heating and drying, which effectively improves the drying and forming quality.
[0016] (3) During the downward movement of the support frame, the cam groove on the lifting column, together with the protrusion on the rotating rod, can change the vertical movement of the lifting column into the rotational movement of the rotating rod. Under the action of gear meshing transmission, it can drive the turntables at both ends to rotate. With the help of the rotational connection of the swing rod, the baffle plate moves at the ventilation hole, thereby reducing the area of the ventilation hole, so that the temperature inside the processing box can rise, and to a certain extent play a temperature control effect, so as to adapt to the drying work of more L-threonine at this time. The degree of automation is high, and the weight of L-threonine plays an automatic temperature control effect. Attached Figure Description
[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0018] Figure 1 This is a schematic flowchart of a highly efficient extraction and purification method for L-threonine fermentation broth according to the present invention. Figure 2 This is a schematic diagram of the processing box of the present invention; Figure 3 This is a schematic diagram of the interior of the processing box of the present invention. Figure 1 ; Figure 4 This is a schematic diagram of the interior of the processing box of the present invention. Figure 2 ; Figure 5 This is a schematic diagram of the meshing transmission of the rotating gear of the present invention; Figure 6 This is a schematic diagram showing the connection between the lifting column and the rotating rod of the present invention; Figure 7 This is a schematic diagram of the meshing transmission of the first bevel gear and the second bevel gear of the present invention; Figure 8 This is the present invention. Figure 4 Enlarged view of point A; Figure 9 This is a schematic diagram of the internal structure of the telescopic tube of the present invention.
[0019] Reference numerals: 1. Drying mechanism; 2. Processing box; 3. Spiral tube; 4. Opening; 5. Panel; 6. First spring; 7. Support frame; 8. Movable part; 9. Lifting column; 10. Rotating rod; 11. Cam groove; 12. Protrusion; 13. First bevel gear; 14. Movable shaft; 15. Second bevel gear; 16. Cover; 17. Turntable; 18. Baffle plate; 19. Swing rod; 20. Limiting groove; 21. Ventilation hole; 22. Bending rod; 23. Housing; 24. First gear plate; 25. Second gear plate; 26. Elastic airbag; 27. First conduit; 28. Telescopic tube; 29. Second conduit; 30. First sealing plug; 31. Second sealing plug; 32. Push rod; 33. Second spring; 34. Heater; 35. Spreading plate; 36. Telescopic rod; 37. Rotating gear. Detailed Implementation
[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0021] Reference manual attached Figure 1 As shown, a highly efficient extraction and purification method for L-threonine fermentation broth includes the following steps: S1. Cool the L-threonine fermentation broth to 20-25°C, and separate the fermentation broth by centrifuging at 3000-3500 rpm to obtain clear liquid and wet crystals respectively. S2. The clarified liquid is heated to 60°C through a heat exchanger. The clarified liquid is then filtered through a ceramic membrane with a pore size of 0.02μm. When the volume of the remaining clarified liquid is one-third of the original clarified liquid volume, dialysis water is added. The amount of dialysis water added is 15-30% of the fermentation liquid volume. The ratio of the volume of the ceramic membrane filtrate to the volume of the clarified liquid is 1:7-10. The ceramic membrane filtrate with an L-threonine content of 5g / L or higher is collected. S3. The ceramic membrane filtrate from step S2 is fed into an electrodialysis unit. Under a DC electric field, inorganic salts are removed by permeating the ion-exchange membrane. After desalting, the clear liquid is evaporated and concentrated to a concentration of 150-220 g / L. S4. After concentration, the pH of the clear liquid is adjusted to 5.1-6.0 with HCl. The temperature is controlled to 20 degrees Celsius by cooling it down by 5 degrees Celsius per hour. Crystallization is carried out for 8-12 hours to form uniform large-particle crystals. S5. Dissolve the crystals from step S4 in heated pure water at 60°C with a weight of one-third that of the crystals, and add 0.5-1% activated carbon by weight of the crystals. Decolorize for 30-60 minutes. S6. The crystal slurry obtained in step S5 is cooled to 30-40°C in a crystallization tank and centrifuged. Washing water is gradually added during the centrifugation process. The resulting wet crystals have a moisture content of 12%. The centrifuged wet crystals are then sent to a drying unit for drying until the moisture content is <0.5%. Example 1
[0022] A highly efficient method for the extraction and purification of L-threonine fermentation broth includes the following steps: S1. Take 1000 L of L-threonine fermentation broth after fermentation, wherein the mass concentration of L-threonine in the fermentation broth is 85-110 g / L. First, cool it to 22℃ using a plate heat exchanger, and then pass it into a centrifuge for solid-liquid separation. The centrifugation speed is controlled at 3200 rpm and the centrifugation time is 15 min to obtain clear liquid and wet crystals respectively. The clear liquid is collected for later use. S2. The clarified liquid obtained in step S1 is heated to 60°C via a heat exchanger and then filtered through a ceramic membrane filtration system with a pore size of 0.02 μm. During filtration, the transmembrane pressure is controlled at 0.15–0.25 MPa, and the circulation flow rate is controlled at 1.5–2.5 m / s. When the volume of the remaining clarified liquid is one-third of the original clarified liquid volume, dialysis water is added to the system, with the amount of dialysis water added being 20% of the fermentation liquid volume. Filtration continues, and the ratio of the volume of the ceramic membrane filtration residue to the volume of the clarified liquid is controlled at 1:8. The resulting filtrate is tested, and the ceramic membrane filtrate with an L-threonine content of 5 g / L or higher is collected. S3. The ceramic membrane filtrate collected in step S2 is sent to an electrodialysis unit for desalination. During electrodialysis, the voltage is controlled at 18–24 V, the current density at 150–250 A / m², the feed flow rate at 1.0–1.5 m³ / h, and the circulation time is 40–90 min. The desalination endpoint is defined as the feed conductivity decreasing to 25–40% of the initial conductivity. After desalination, the clarified liquid is sent to a vacuum evaporation and concentration unit and concentrated to an L-threonine concentration of 180 g / L under conditions of -0.06–-0.08 MPa. S4. Transfer the concentrated clear liquid from step S3 into a crystallizer, adjust the pH to 5.5 with a 10% hydrochloric acid solution, and stir at 200-300 rpm for 20 minutes to ensure uniform mixing. Then, cool the liquid to 20°C at a rate of 5°C per hour using a cooler, and grow crystals at 20°C for 10 hours to obtain a crystal slurry containing larger crystal particles. S5. Heat the crystal slurry obtained in step S4 to 60°C to redissolve the crystals; add pure water at 60°C, the amount of which is one-third of the weight of the crystals; after the crystals are fully dissolved, add 0.8% of the weight of the crystals of activated carbon, and decolorize at 60°C for 45 min; after decolorization, filter to remove the activated carbon and adsorbed impurities, and obtain the decolorized clear liquid. S6. Place the decolorized clear liquid obtained in step S5 into a crystallization tank, cool it to 35 ℃ and then centrifuge it. The centrifugation speed is controlled at 3200-3400 rpm. During the centrifugation process, wash water is gradually added by atomized spraying. The amount of wash water added is 8-12% of the mass of the crystal slurry. After centrifugation, wet crystals are obtained and their moisture content is controlled at 12%. The obtained wet crystals are sent to the drying treatment unit 1 for drying until the product moisture content is less than 0.5%, and L-threonine product is obtained.
[0023] This embodiment uses an intermediate parameter combination that is at a moderate level in terms of the amount of dialysis water added, the concentration at the concentration endpoint, the pH value adjustment, the crystal growth time, and the amount of activated carbon added. It achieves a good balance between recovery rate, purity, crystal particle size, operational stability, and energy consumption, and can effectively remove impurities, reduce salt interference, form uniform large-particle crystals, and finally dry to low moisture content. Example 2
[0024] A highly efficient method for the extraction and purification of L-threonine fermentation broth includes the following steps: S1. Take 800 L of L-threonine fermentation broth after fermentation, cool it to 25℃, and then separate it by centrifugation at 3500 rpm for 12 min to obtain clear liquid and wet crystals. S2. After heating the supernatant to 60℃, it enters a ceramic membrane filtration device with a pore size of 0.02μm; the transmembrane pressure is controlled at 0.20 MPa; when the volume of the remaining supernatant is one-third of the original supernatant volume, dialysis water is added, and the amount of dialysis water added is 15% of the fermentation broth volume; filtration continues, and the volume ratio of the retentate to the supernatant is controlled at 1:7; the filtrate with an L-threonine content greater than 5 g / L is collected. S3. The filtrate obtained in step S2 is subjected to electrodialysis for desalination. The voltage is controlled at 20 V and the current density is controlled at 180 A / m² for 60 min. After desalination, it is concentrated by vacuum evaporation so that the concentration of L-threonine in the clear liquid reaches 150 g / L. S4. Adjust the pH of the concentrate to 5.1 with hydrochloric acid, cool it down to 20°C at a rate of 5°C per hour, and allow it to crystallize for 8 hours to obtain the primary crystallization slurry. S5. The crystals obtained in step S4 are redissolved in hot pure water at 60°C, with the amount of pure water added being one-third of the weight of the crystals; 0.5% of the weight of the crystals is added to activated carbon for decolorization for 30 min, and the activated carbon is removed by filtration. S6. After cooling the decolorized crystal slurry to 30°C, centrifuge it while gradually adding washing water during the centrifugation process. The amount of washing water added is 6-10% of the mass of the crystal slurry. Control the moisture content of the resulting wet crystals to 12%. Then send them to the drying treatment unit 1 for drying until the product moisture content is below 0.5%.
[0025] This embodiment uses a combination of relatively low parameters, with relatively small amounts of dialysis water, concentration at the final concentration, crystal growth time, and activated carbon, resulting in a shorter processing cycle and relatively lower consumption of materials and auxiliary materials. This is beneficial for shortening the process cycle, reducing the consumption of activated carbon and washing water, and alleviating the operational burden during the crystallization and decolorization stages.
[0026] Reference manual attached Figure 2-9 The drying processing mechanism 1 includes a processing box 2 with a conical opening. A spiral tube 3 connected to the conical opening is installed on the top of the inner wall of the processing box 2. The bottom of the spiral tube 3 extends downward, and there are equally spaced openings 4 in the length direction of the bottom of the spiral tube 3. A panel 5 is fixedly connected to the inner wall of the processing box 2 by a bracket. The top two sides of the panel 5 are connected to a support frame 7 placed below the spiral tube 3 by a first spring 6.
[0027] Specifically, the top of the support frame 7 is provided with a slot that matches it, and both ends of the support frame 7 are telescopically connected with movable parts 8. A lifting column 9 is fixedly installed at the center of the bottom of the support frame 7. The bottom of the lifting column 9 passes through the panel 5 and extends to the rotating rod 10. The panel 5 is provided with a movable hole that connects to the lifting column 9. A cam groove 11 is provided on the outer edge of the lifting column 9. The outer wall of the cam groove 11 movably abuts against the protrusion 12 of the inner wall of the rotating rod 10. The bottom of the rotating rod 10 is connected to the inner wall of the processing box 2 through a bearing.
[0028] The opening 4 at the bottom of the spiral tube 3 along its length is equivalent to a discharge port. When too much L-threonine falls, it can be discharged through multiple openings 4. A single discharge port will cause L-threonine to accumulate in a specific position, which is not conducive to the subsequent uniform drying work.
[0029] The bearing at the bottom of the inner wall of the processing box 2 can provide corresponding support for the rotating rod 10 and ensure its free rotation, preventing position deviation during rotation and ensuring the stability of the transmission components.
[0030] A first bevel gear 13 is fixedly installed on the rotating rod 10. Both ends of the outer wall of the first bevel gear 13 are meshed with a second bevel gear 15 fixed on the movable shaft 14. One end of the movable shaft 14 passes through the cover 16 and extends to the turntable 17. The protrusion on the turntable 17 and the baffle plate 18 are connected by a swing rod 19. The baffle plate 18 has a limit groove 20 along the height direction of the side wall of the processing box 2.
[0031] By using automated temperature control, L-threonine crystals can be effectively and uniformly dried. During the descent of the spiral tube 3, the L-threonine crystals, in conjunction with the heater 34 inside the processing chamber 2, achieve uniform heating. Furthermore, the opening 4 along the length of the bottom of the spiral tube 3 facilitates heat entry into the spiral tube 3 for drying and ensures the L-threonine crystals are evenly distributed within the support frame 7. When the L-threonine crystals enter the support frame 7, their own gravity causes the support frame 7 to move downwards on the first spring 6. Through gear meshing, the second gear plate 25 drives the support frame... The movable parts 8 at both ends of the support frame 7 move outward to expand the bearing area. At the same time, during the compression process of the support frame 7 and the elastic airbag 26, the elastic airbag 26 provides a corresponding buffering effect and can also drive the gas to move the first sealing plug 30 towards the telescopic tube 28. The setting of the telescopic tube 28 can facilitate the normal up and down movement of the support frame 7 and can also further push the second sealing plug 31 outward through compression. The second sealing plug 31 drives the spreading plate 35 to move synchronously within the support frame 7. Through the pushing and spreading action, L-threonine is evenly spread on the support frame 7 and heated and dried, which effectively improves the drying and molding quality.
[0032] Specifically, both ends of the swing rod 19 are mounted on the turntable 17 and the baffle plate 18 by means of rotational connection. One end of the cover 16 is mounted on the side wall of the processing box 2 by the first fixing rod. A ventilation hole 21 is formed between the baffle plate 18 and the limiting groove 20 on the inner wall of the processing box 2. Bending rods 22 are fixedly installed on both sides of the bottom end of the bearing frame 7. One end of the bending rod 22 is connected to a first gear plate 24 extending into the inside of the housing 23. The outer wall of the first gear plate 24 is connected to a horizontally distributed second gear plate 25 through the meshing of the rotating gear 37. One end of the second gear plate 25 penetrates the housing 23 and extends to the movable part 8 of the bearing frame 7.
[0033] One end of the housing 23 is connected to the side wall of the processing box 2 via a second fixing rod. The support frame 7 and the panel 5 are connected by an elastic airbag 26. One end of the airbag 26 is connected to a vertically distributed telescopic tube 28 via a first conduit 27. A second conduit 29 is installed at the extended end of the outer wall of the telescopic tube 28. The outer edge of the second conduit 29 is provided with an annular opening placed on the support frame 7. The annular opening is mainly for fixing the second conduit 29. In this way, the support frame 7 can transmit the force to the telescopic tube 28 during the up and down movement and compress or release the internal pressure.
[0034] During the downward movement of the support frame 7, the cam groove 11 on the lifting column 9, in conjunction with the protrusion 12 on the rotating rod 10, can convert the vertical movement of the lifting column 9 into the rotational movement of the rotating rod 10. Under the action of gear meshing transmission, it can drive the turntables 17 at both ends to rotate. With the help of the rotational connection of the swing rod 19, the baffle 18 moves at the ventilation hole 21, thereby reducing the area of the ventilation hole 21, so that the internal temperature of the processing box 2 can rise, and it also plays a certain role in temperature control. This is to adapt to the drying work of a large number of L-threonines at this time. The degree of automation is high, and the weight of L-threonines plays a role in automatic temperature control.
[0035] In other words, as the carrier frame 7 moves upward, it means that the amount of L-threonine decreases. The rotating rod 10 rotates, and at this time, the baffle plate 18 moves at the ventilation hole 21, thereby expanding the area of the ventilation hole 21, so that the internal temperature of the processing box 2 can be reduced, thus adapting to the drying of a small amount of L-threonine at this time. After the L-threonine crystal drying operation is completed, the heater 34 is turned off, and then it can be removed by manual operation, which is convenient for operation.
[0036] The inner walls of the first conduit 27 and the second conduit 29 are respectively slidably connected to a first sealing plug 30 and a second sealing plug 31. One end of the second sealing plug 31 is connected to a spreading plate 35 via a push rod 32, and the other end is connected to the inner wall of the second conduit 29 via a second spring 33. A movable cavity is formed between the spreading plate 35 and the support frame 7. Both ends of the spiral tube 3 are fixedly connected to the side wall of the processing box 2 via crossbeams, and a heater 34 adapted to it is detachably fixedly installed on the inner wall of the processing box 2. The detachable installation method facilitates personnel operation and subsequent maintenance and replacement, thereby improving work efficiency.
[0037] The above are merely preferred embodiments 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.
[0038] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to specific implementations. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.
Claims
1. A highly efficient method for the extraction and purification of L-threonine fermentation broth, characterized in that, Includes the following steps: S1. Cool the L-threonine fermentation broth to 20-25°C, and separate the fermentation broth by centrifuging at 3000-3500 rpm to obtain clear liquid and wet crystals respectively. S2. The clarified liquid is heated to 60°C through a heat exchanger. The clarified liquid is then filtered through a ceramic membrane with a pore size of 0.02μm. When the volume of the remaining clarified liquid is one-third of the original clarified liquid volume, dialysis water is added. The amount of dialysis water added is 15-30% of the fermentation liquid volume. The ratio of the volume of the ceramic membrane filtrate to the volume of the clarified liquid is 1:7-10. The ceramic membrane filtrate with an L-threonine content of 5g / L or higher is collected. S3. The ceramic membrane filtrate from step S2 is fed into an electrodialysis unit. Under a DC electric field, inorganic salts are removed by permeating the ion-exchange membrane. After desalting, the clear liquid is evaporated and concentrated to a concentration of 150-220 g / L. S4. After concentration, the pH of the clear liquid is adjusted to 5.1-6.0 with HCl. The temperature is controlled to 20 degrees Celsius by cooling it down by 5 degrees Celsius per hour. Crystallization is carried out for 8-12 hours to form uniform large-particle crystals. S5. Dissolve the crystals from step S4 in heated pure water at 60°C with a weight of one-third that of the crystals, and add 0.5-1% activated carbon by weight of the crystals. Decolorize for 30-60 minutes. S6. The crystal slurry obtained in step S5 is cooled to 30-40°C in the crystallization tank and centrifuged. Washing water is gradually added during the centrifugation process. The resulting wet crystals have a moisture content of 12%. The centrifuged wet crystals are sent to the drying treatment unit (1) for drying. The moisture content is dried to <0.5%.
2. The method for efficient extraction and purification of L-threonine fermentation broth according to claim 1, characterized in that, The drying processing mechanism (1) includes a processing box (2) with a conical opening. A spiral tube (3) connected to the conical opening is installed on the top of the inner wall of the processing box (2). The bottom of the spiral tube (3) extends downward, and there are equally spaced openings (4) in the length direction of the bottom of the spiral tube (3). A panel (5) is fixedly connected to the inner wall of the processing box (2) by a bracket. The top two sides of the panel (5) are connected to a support frame (7) placed below the spiral tube (3) by a first spring (6).
3. The method for efficient extraction and purification of L-threonine fermentation broth according to claim 2, characterized in that, The top of the support frame (7) is provided with a slot that matches it, and both ends of the support frame (7) are connected to movable parts (8) for telescopic extension. A lifting column (9) is fixedly installed at the center of the bottom of the support frame (7). The bottom of the lifting column (9) passes through the panel (5) and extends to the rotating rod (10). The panel (5) is provided with a movable hole connected to the lifting column (9). A cam groove (11) is provided on the outer edge of the lifting column (9). The outer wall of the cam groove (11) moves against the protrusion (12) of the inner wall of the rotating rod (10). The bottom of the rotating rod (10) is connected to the inner wall of the processing box (2) through a bearing.
4. The efficient extraction and purification method for L-threonine fermentation broth according to claim 3, characterized in that, A first bevel gear (13) is fixedly installed on the rotating rod (10). Both ends of the outer wall of the first bevel gear (13) are meshed with a second bevel gear (15) fixed on the movable shaft (14). One end of the movable shaft (14) passes through the cover (16) and extends to the turntable (17). The protrusion on the turntable (17) and the baffle plate (18) are connected by a swing rod (19). The baffle plate (18) has a limit groove (20) opened along the height direction of the side wall of the processing box (2).
5. The method for efficient extraction and purification of L-threonine fermentation broth according to claim 4, characterized in that, Both ends of the swing rod (19) are mounted on the turntable (17) and the baffle plate (18) by means of rotational connection. One end of the cover (16) is mounted on the side wall of the processing box (2) by the first fixing rod. A ventilation hole (21) is formed between the baffle plate (18) and the limiting groove (20) on the inner wall of the processing box (2). Both sides of the bottom end of the bearing frame (7) are fixedly installed with bending rods (22). One end of the bending rod (22) is connected to a first gear plate (24) extending into the inside of the housing (23). The outer wall of the first gear plate (24) is connected to a horizontally distributed second gear plate (25) through the meshing of the rotating gear (37). One end of the second gear plate (25) penetrates the housing (23) and extends to the movable part (8) of the bearing frame (7).
6. The method for efficient extraction and purification of L-threonine fermentation broth according to claim 5, characterized in that, The second gear plate (25) and the movable part (8) are connected by a telescopic rod (36). One end of the housing (23) is connected to the side wall of the processing box (2) by a second fixed rod. The support frame (7) and the panel (5) are connected by an elastic airbag (26). One end of the air hole on the elastic airbag (26) is connected to a vertically distributed telescopic tube (28) through a first conduit (27). The extension end of the outer wall of the telescopic tube (28) is equipped with a second conduit (29). The outer edge of the second conduit (29) is provided with an annular opening placed on the support frame (7).
7. The method for efficient extraction and purification of L-threonine fermentation broth according to claim 6, characterized in that, The inner walls of the first conduit (27) and the second conduit (29) are respectively slidably connected with a first sealing plug (30) and a second sealing plug (31). One end of the second sealing plug (31) is connected to a spreading plate (35) via a push rod (32), and the other end is connected to the inner wall of the second conduit (29) via a second spring (33). An active cavity is formed between the spreading plate (35) and the support frame (7).
8. The method for efficient extraction and purification of L-threonine fermentation broth according to claim 2, characterized in that, Both ends of the spiral tube (3) are fixedly connected to the side wall of the processing box (2) through crossbeams, and a heater (34) adapted to it is detachably fixedly installed on the inner wall of the processing box (2).