Method for producing L-valine crystals and / or granules using pH adjustment

Abstract

This application relates to a method for producing valine crystals and / or valine granules using pH adjustment.

Description

Technical Field

[0001] This application relates to a method for producing valine crystals and granules, which forms valine crystals and mixed granules with low moisture content, reduces the amount of steam required during the production of valine granules, and improves the production efficiency of valine granules.

Background Art

[0002] In order to obtain high-purity amino acids by fermentation, a separation or purification step of amino acids for removing by-products after the fermentation process stage is essential.

[0003] However, for amino acid products for feed, high-content (98% or more) products are not necessary, and it is more appropriate to produce granular products with a high content (70% or more) without generating waste in the purification step while including other nutritionally valuable components contained in the fermentation broth.

[0004] In the conventional technology (US 7514111 B2), in order to produce amino acid granular products for feed additives, after evaporating a large amount of water in the fermentation broth, a fluidized bed granulator is used to produce granules. In the case of amino acids with high solubility, even if the water is evaporated to a solid content of about 60 - 65% (moisture content 35 - 40%), crystals are not formed, so granulation is possible by the fluidized bed granulation method in which the fermentation broth is sprayed through a nozzle. However, valine has low solubility and crystals are formed even when the solid content in the fermentation broth is low at about 12 - 15% (moisture content 85 - 88%), so the moisture content of the fermentation broth cannot be lowered to prevent crystal formation. Therefore, a large amount of water must be evaporated during the drying process, so a large amount of energy consumption is required during drying.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

[0006] The present application aims to provide a method for producing valine crystals, comprising the steps of: preparing a fermentation liquid containing valine; adjusting the pH of the fermentation liquid; concentrating the fermentation liquid to prepare a concentrated fermentation liquid; and separating water-containing valine crystals from the concentrated fermentation liquid.

[0007] Furthermore, this application aims to provide a method for producing valine granules, comprising the steps of: preparing a fermentation liquid containing valine; adjusting the pH of the fermentation liquid; concentrating the fermentation liquid to prepare a concentrated fermentation liquid; separating water-containing valine crystals from the concentrated fermentation liquid; mixing the valine crystals with seeds to produce valine mixed granules; and drying the valine mixed granules. [Means for solving the problem]

[0008] This application provides a method for producing valine crystals, comprising the steps of: preparing a fermentation liquid containing valine; adjusting the pH of the fermentation liquid; concentrating the fermentation liquid to prepare a concentrated fermentation liquid; and separating water-containing valine crystals from the concentrated fermentation liquid.

[0009] Furthermore, this application provides a method for producing valine granules, comprising the steps of: preparing a fermentation liquid containing valine; adjusting the pH of the fermentation liquid; concentrating the fermentation liquid to prepare a concentrated fermentation liquid; separating water-containing valine crystals from the concentrated fermentation liquid; mixing the valine crystals with seeds to produce valine mixed granules; and drying the valine mixed granules. [Effects of the Invention]

[0010] According to this application, a fermentation liquid containing valine can be concentrated to separate valine wet crystals, and the separated valine wet crystals can be mixed with seeds to produce valine mixed granules that are large in size and have a low moisture content. Valine mixed granules with a low moisture content have the advantage of requiring less energy for drying. In particular, according to this application, the moisture content in the valine mixed granules can be further reduced by adjusting the pH of the fermentation liquid and / or adjusting the concentration rate. [Modes for carrying out the invention]

[0011] This can be explained in more detail as follows: On the other hand, each description and embodiment disclosed in this application also applies to each other description and embodiment. That is, all combinations of the various elements disclosed in this application fall within the scope of this application. Furthermore, the categories of this application are not considered to be limited by the specific descriptions described below.

[0012] Furthermore, a person with ordinary skill in the art would be able to recognize and confirm many equivalents of the particular aspects of the present invention described in this application using only ordinary experiments. Such equivalents are intended to be included in this application.

[0013] As used in the specification and attached claims of this application, singular articles ("a," "an," and "the") include multiple references unless explicitly stated otherwise in context. Unless otherwise specified in context, singular terms include plurals, and plural terms include singulars. In the specification and attached claims of this application, unless otherwise specified, the use of "or" is used to include "and / or."

[0014] In this application, the term "about" is presented before a specific number. As used in this application, "about" includes not only the exact number that follows, but also a range that is approximately that number or close to it. The context in which the number is presented can be considered to determine whether it is close to or approximately that specific number. For example, the term "about" could refer to a range of 10% to +10% of a number. Another example is that the term "about" could refer to a range of -5% to +5% of a given number. However, it is not limited to these examples.

[0015] This application relates to a method and apparatus for producing valine granules. By forming valine mixed granules, which are a mixture of valine wet crystals and seeds, and then drying them, the amount of steam consumed in the production process of valine, an amino acid with low solubility, can be reduced, thereby increasing the efficiency of valine granule production.

[0016] The method for producing valine crystals according to this application includes the steps of: preparing a fermentation liquid containing valine; adjusting the pH of the fermentation liquid; concentrating the fermentation liquid to prepare a concentrated fermentation liquid; and separating water-containing valine crystals from the concentrated fermentation liquid. Each step will be described in detail below.

[0017] The step of preparing the fermentation liquid is the step of preparing a fermentation liquid containing valine. Valine contained in the fermentation liquid is an amino acid with low solubility in water. In this case, low solubility does not mean that the solubility is below a certain standard. The fermentation liquid prepared in the step of preparing the fermentation liquid may be a fermented product prepared by the metabolism of a bacterial strain. In this application, the term "fermented product" means the result of the enzymatic or metabolic decomposition of organic matter using a microorganism, for example, a microorganism that produces valine. For example, the fermented product includes the culture itself obtained by culturing a microorganism in a culture medium, or a concentrate, dried or freeze-dried product of the culture obtained by removing the bacterial strain therefrom. In addition, in this case, the fermentation liquid may include the entire valine-containing fermented product, or it may be a valine-containing fermented product from which impurities have been removed.

[0018] The fermentation liquid mainly consists of valine, but may also contain other components. For example, the fermentation liquid may further contain amino acids other than valine, organic acids, and inorganic substances, which may be dissolved in water. The concentration of valine in the fermentation liquid may be approximately 1 g / L to approximately 200 g / L. However, the valine concentrations mentioned above are merely illustrative, and fermentation liquids with concentrations outside the range mentioned above can also be used in the valine crystal production method according to this application.

[0019] The "valine-producing microorganisms" or "microorganisms capable of producing valine" used in the preparation of the fermentation liquid in this application include all wild-type microorganisms that naturally possess valine-producing ability, as well as microorganisms that have undergone natural or artificial genetic modification, in which valine-producing ability has been conferred to parent strains that previously lacked it. These microorganisms may also be microorganisms in which specific mechanisms have been weakened or strengthened due to causes such as the insertion of external genes or the strengthening or inactivation of the activity of endogenous genes, and may include microorganisms that have undergone genetic modification for the production of the target amino acid, i.e., valine. Specifically, the valine-producing microorganisms or microorganisms capable of producing valine in this application may be microorganisms in which a portion of the genes in the biosynthesis pathway of the target product, valine, has been strengthened or weakened, or a portion of the genes in the valine degradation pathway has been strengthened or weakened. "Strengthened" or "increased" valine-producing ability of the microorganisms in this application means that the valine-producing ability of the microorganisms in this application has improved compared to other microorganisms, parent strains, or non-mutated microorganisms. For example, the microorganism of this application may have a valine production capacity that is approximately 1% or more, 10% or more, 100% or more, 200% or more, 500% or more, 1000% or more, 1100% or more, 1200% or more, or 1300% or more higher than that of other microorganisms, and may also have an improvement of approximately 1.01 times or more, 2 times or more, 5 times or more, 10 times or more, 11 times or more, 12 times or more, or 13 times or more, but is not limited thereto. The term "approximately" includes all ranges such as ±0.5, ±0.4, ±0.3, ±0.2, ±0.1, and includes all numerical values ​​in a range equivalent to or similar to the numerical value following the term "approximately," but is not limited thereto.

[0020] The aforementioned microorganisms used in the preparation of the fermentation liquid of this application may be at least one selected from the group consisting of the yeast Candida famata, the ascomycetes Eremothecium ashbyii and Ashbya gossypii, the bacteria Bacillus subtilis, and microorganisms of the genus Corynebacterium sp.

[0021] For example, if the microorganisms used in the step of preparing the fermentation liquid of this application are Corynebacterium species, then these microorganisms are specifically Corynebacterium glutamicum, Corynebacterium crudilactis, Corynebacterium deserti, Corynebacterium efficiens, Corynebacterium callunae, Corynebacterium stationis, Corynebacterium singulare, Corynebacterium halotolerans, and Corynebacterium striatum. It may also be Corynebacterium striatum, Corynebacterium ammoniagenes, Corynebacterium pollutisoli, Corynebacterium imitans, Corynebacterium testudinoris, Corynebacterium crenatum, or Corynebacterium flavescens, and more specifically, it may be Corynebacterium glutamicum, but is not limited thereto.

[0022] Microorganisms of the genus Corynebacterium, particularly Corynebacterium glutamicum, are Gram-positive microorganisms that are widely used in the production of L-amino acids and other useful substances. In order to produce the L-amino acids and other useful substances, various studies have been conducted for the development of highly efficient production microorganisms and fermentation process technologies. For example, a target substance-specific approach such as increasing the expression of genes encoding enzymes involved in the biosynthesis of L-valine or removing genes unnecessary for biosynthesis is mainly used. In this application, a fermentation broth containing amino acids can also be prepared using a strain of the genus Corynebacterium.

[0023] According to one specific example of this application, Corynebacterium glutamicum utilized to prepare a fermentation broth containing valine may be an overexpressing strain of L-valine biosynthesis in which Corynebacterium glutamicum ATCC13032 is transformed and the regulatory site of L-valine biosynthesis is inactivated, but is not limited thereto. Or the Corynebacterium glutamicum may be a strain transformed with pDZDvalL, pDZDvalP, pDZDvalS vectors using the chromosomes of Corynebacterium glutamicum KCCM11201P, Corynebacterium glutamicum KCCM11336P, Corynebacterium glutamicum KCCM11337P, Corynebacterium glutamicum KCCM11338P, Corynebacterium glutamicum KCCM11201P_DvalA as templates. According to other exemplifications, the Corynebacterium glutamicum may be Corynebacterium glutamicum ATCC13032_DvalL, Corynebacterium glutamicum ATCC13032_DvalP, or Corynebacterium glutamicum ATCC13032_DvalS strain, but is not limited thereto, and includes without limitation microorganisms capable of producing a fermentation broth containing valine (US 10072278 B2).

[0024] The step of preparing the fermentation broth can further include the step of culturing "the microorganism that produces valine". The culturing of the microorganism can be carried out according to appropriate media and culturing conditions known in the art. Such a culturing process can be easily adjusted and used by those skilled in the art according to the selected bacterial strain. Specifically, the culturing may be batch, continuous, or fed-batch, but is not limited thereto.

[0025] In the present application, the term "medium" means a substance mixed mainly with nutrients required for culturing the microorganism, and supplies nutrients such as water, which is essential for survival and growth, and growth factors. Specifically, the medium and other culturing conditions used for culturing the microorganism of the present application can be used without any special restrictions as long as they are media used for culturing ordinary microorganisms. However, the microorganism of the present application can be cultured under aerobic conditions while adjusting temperature, pH, etc. in an ordinary medium containing an appropriate carbon source, nitrogen source, phosphorus source, inorganic compound, amino acid, and / or vitamin.

[0026] Next, the step of adjusting the pH of the fermentation broth is carried out. Here, the pH of the fermentation broth can be adjusted to be greater than about 3.0 and less than 6.0. In some cases, the pH of the fermentation broth can be adjusted to be about 3.5 to less than 6.0, about 4.0 to less than 6.0, about 4.5 to less than 6.0, about 5.0 to less than 6.0, about 5.5 to less than 6.0, about greater than 3.0 to 5.5, about 3.5 to 5.5, about 4.0 to 5.5, about 4.5 to 5.5, about 5.0 to 5.5, about greater than 3.0 to 5.0, about 3.5 to 5.0, about 4.0 to 5.0, about 4.5 to 5.0, about greater than 3.0 to 4.5, about 3.5 to 4.5, about 4.0 to 4.5, about greater than 3.0 to 4.0, about 3.5 to 4.0, or about greater than 3.0 to 3.5.

[0027] By adjusting the pH of the fermentation liquid, the size and hardness of the valine crystals formed in the subsequent concentration stage can be controlled. Specifically, when the pH of the fermentation liquid is adjusted within the aforementioned range before concentration, large and hard valine crystals may form, which reduces the water content of the separated valine crystals. If the pH of the fermentation liquid is outside the aforementioned range, the crystal size of the valine crystals precipitated after concentration is small, making it difficult to separate the valine crystals from the mother liquor of the fermentation liquid. In addition, a relatively large amount of water is separated along with the valine crystals, requiring a lot of energy for subsequent drying.

[0028] pH adjustment in the fermentation broth stage can be carried out using ordinary acidic or basic substances. However, the substances added to the fermentation broth for pH adjustment can be determined within limits that do not affect the physical properties or chemical structure of the valine contained in the fermentation broth. Furthermore, considering that valine products are used for food or animal feed, edible acidic or basic substances may also be added.

[0029] After the pH adjustment described above, if necessary, steps such as heating the fermentation liquid may be taken to completely dissolve the valine precipitated in the fermentation liquid. For example, the fermentation liquid can be heated to approximately 60°C to 90°C.

[0030] After adjusting the pH of the fermentation liquid, the prepared fermentation liquid is concentrated to create a concentrated fermentation liquid.

[0031] In the concentration stage, water is removed from the fermentation liquid to precipitate valine in crystalline form. Concentration can be carried out by a variety of methods. Concentration may be carried out in a conventional concentrator (e.g., a paddle dryer, slurry dryer, vacuum concentrator, forced-circulation concentrator, thin-film concentrator, or rotary concentrator) as appropriate by those skilled in the art.

[0032] In the concentration stage, concentration may be carried out by removing water from the fermentation liquor at a rate of 60 g / L / hr to 150 g / L / hr (meaning removing 60 g to 150 g of water per liter of fermentation liquor in one hour). In some cases, concentration may be carried out by removing water from the fermentation liquor at a rate of 90 g / L / hr to 150 g / L / hr, 120 g / L / hr to 150 g / L / hr, 60 g / L / hr to 120 g / L / hr, 90 g / L / hr to 120 g / L / hr, or 60 g / L / hr to 90 g / L / hr. In this application, the concentration rate is a factor that affects the size of the valine crystals. When concentrated at the rates described above, relatively large valine crystals are formed, and the valine crystals can be easily separated from the mother liquor of the fermentation liquor. In addition, this reduces the water content in the valine crystals.

[0033] Next, a separation step is performed in which the valine crystals precipitated during the concentration stage are separated from the mother liquor.

[0034] In the separation stage, water-containing valine crystals are separated from the concentrated fermentation liquid. At this time, solid-liquid separators such as vacuum membrane filters, pressure membrane filters, and centrifuges can be used. However, the means described above are illustrative, and the means for performing the separation stage are not limited to those described above.

[0035] The mother liquor remaining after valine crystal separation can be used for further concentration during the separation stage. This allows for the recycling of valine that did not form wet crystals during the concentration stage, or valine that precipitated into crystals below a certain size and remained in the mother liquor without being separated during the valine crystal separation stage. Furthermore, after the mother liquor circulation, additional steps may be taken, such as heating the fermentation liquid to further dissolve the valine precipitated in the form of fine crystals, if necessary.

[0036] According to the valine crystal production method described above in this application, valine crystals with low water content and easy separation can be obtained by adjusting the pH of the fermentation liquid containing valine and concentrating the fermentation liquid at an appropriate rate.

[0037] A valine crystal manufactured according to one aspect of this application may have a viscosity greater than 0 cp and less than 80 cp. In some cases, the viscosity of the valine crystal may be greater than 10 cp and less than 80 cp, greater than 15 cp and less than 80 cp, greater than 20 cp and less than 80 cp, greater than 30 cp and less than 80 cp, greater than 40 cp and less than 80 cp, greater than 50 cp and less than 80 cp, greater than 60 cp and less than 80 cp, greater than 0 cp and less than 70 cp, greater than 10 cp and less than 70 cp, greater than 15 cp and less than 70 cp, greater than 20 cp and less than 70 cp, greater than 30 cp and less than 70 cp, greater than 40 cp and less than 70 cp, greater than 50 cp and less than 70 cp, greater than 60 cp and less than 70 cp, greater than 0 cp and less than 50 cp, greater than 10 cp and less than 50 cp, 15 The viscosity can be greater than cp but less than 50 cp, greater than 20 cp but less than 50 cp, greater than 30 cp but less than 50 cp, greater than 40 cp but less than 50 cp, greater than 0 cp but less than 30 cp, greater than 10 cp but less than 30 cp, greater than 15 cp but less than 30 cp, greater than 20 cp but less than 30 cp, greater than 0 cp but less than 25 cp, greater than 10 cp but less than 25 cp, greater than 20 cp but less than 25 cp, greater than 0 cp but less than 20 cp, greater than 0 cp but less than 20 cp, greater than 0 cp but less than 20 cp, greater than 0 cp but less than 15 cp, greater than 10 cp but less than 15 cp, or greater than 0 cp but less than 10 cp. Valin crystals having a viscosity within the above range have a low water content and an appropriate size, so they can be easily separated from the mother liquor.

[0038] Valine crystals manufactured according to one aspect of this application may contain 10% to 55% by weight of water. In some cases, the valine crystals may contain 20% to 55% by weight, 30% to 55% by weight, 40% to 55% by weight, 50% to 55% by weight, 10% to 50% by weight, 20% to 50% by weight, 30% to 50% by weight, 40% to 50% by weight, 10% to 40% by weight, 20% to 40% by weight, 30% to 40% by weight, 10% to 30% by weight, 20% to 30% by weight, or 10% to 20% by weight of water. Valine crystals having the aforementioned water content have a relatively low water content and can be used immediately without a separate drying step, or after only a small amount of drying, thus saving energy required in the process.

[0039] A method for producing valine granules includes the steps of: preparing a fermentation liquid containing valine; adjusting the pH of the fermentation liquid; concentrating the fermentation liquid to prepare a concentrated fermentation liquid; separating water-containing valine crystals from the concentrated fermentation liquid; mixing the valine crystals with seeds to produce valine mixed granules; and drying the valine mixed granules.

[0040] Here, the steps of preparing the fermentation liquid, adjusting the pH of the fermentation liquid, concentrating the fermentation liquid, and separating the valine crystals are carried out in the same manner as in the valine crystal production method described above. However, in order to avoid repetition of explanations, the following description will focus on the steps of mixing the valine crystals with seeds to produce mixed granules and drying the mixed granules.

[0041] In the mixed granule manufacturing stage, the valine crystals obtained in the valine crystal separation stage are mixed with seeds for the production of valine granules.

[0042] The seed used in the mixed granule manufacturing stage is also called a seed crystal or seed crystal, and refers to a substance used as a catalyst for the crystallization or granulation of a liquid. In this application, the seed may be a valine crystal. The seed can form granules when it comes into contact with the fermentation liquid, as solid components present in the fermentation liquid combine with the seed and agglomerate.

[0043] The seeds used in the manufacturing stage of the mixed granules may have an average particle size of 150 to 300 μm. Specifically, seeds with an average particle size of 150 to 250 μm, 200 to 300 μm, or 200 to 250 μm may be used, but are not limited thereto. The particle size of the seeds used will ultimately affect the productivity of granule production according to this application, and a person skilled in the art can appropriately select it, taking into consideration the desired moisture content, etc.

[0044] A mixing granulator can be used in the manufacturing stage of the mixed granules. The mixing granulator may produce granules by injecting seeds into the granulator at a constant rate through a feeder and supplying valine crystals obtained in the previous separation stage. The mixing granulator may include a feeder for supplying seeds and a component for supplying valine crystals. The mixing granulator may also be provided with a gas nozzle for generating airflow inside the chamber, a paddle for mixing the seeds and valine crystals provided in the chamber, and so on. The seeds and valine crystals that flow into the chamber solidify together to form amino acid mixed granules.

[0045] According to one aspect of this application, mixed amino acid granules with low moisture content and large crystal size can be produced by mixing seeds and amino acid wet crystals. As previously discussed, according to this application, large valine crystals are precipitated, and since large valine crystals can be easily separated from the fermentation liquid, the moisture content in the valine crystals is relatively low. Furthermore, by granulating valine crystals with low moisture content and seeds in a mixed granulator during the production stage of the mixed granules, the valine mixed granules produced also have low moisture content and large size.

[0046] Here, "granules" are macroscopic particles, which are larger, permanent aggregates formed by the aggregation of smaller particles, such as powder. These particles may have an average diameter of 50 μm to 5 mm, 75 μm to 4 mm, or 100 μm to 3 mm.

[0047] The valine mixed granules obtained during the manufacturing process of the mixed granules may contain 10% to 50% by weight of moisture. In some cases, the valine mixed granules may contain 20% to 50% by weight, 30% to 50% by weight, 40% to 50% by weight, 10% to 40% by weight, 20% to 40% by weight, 30% to 40% by weight, 10% to 30% by weight, 20% to 30% by weight, or 10% to 20% by weight of moisture. This represents a lower moisture content compared to amino acid granules obtained by conventional techniques. Therefore, the amount of energy required to dry the valine mixed granules obtained by this application can be reduced.

[0048] Next, a drying step is performed in which the valine-mixed granules are dried to obtain an amino acid product.

[0049] In the drying stage, the previously obtained valine mixed granules are dried, but there are no restrictions on the drying method. After drying, a valine product can be obtained. In this application, the term "valine product" means that the valine contained in the fermentation liquid has been commercialized in various dosage forms. For example, a valine product means a granular valine-containing mixture. However, if necessary, the dosage form of the valine product may be different, as long as it does not change the concept of the invention of this application. Furthermore, as mentioned above, subsequent processes can be carried out to realize various dosage forms of valine products. The aforementioned valine product can be used as an additive for animal feed, etc., and there are no restrictions on its use.

[0050] According to this application, it is possible to concentrate a fermentation liquid containing amino acids to separate amino acid wet crystals, and then mix the separated amino acid wet crystals with seeds to produce amino acid mixed granules that are large in size and have a low moisture content. Amino acid mixed granules with a low moisture content have the advantage of requiring less energy for drying. In particular, according to this application, the moisture content in the amino acid mixed granules can be further reduced by adjusting the pH of the fermentation liquid or adjusting the concentration rate. [Examples]

[0051] The present application will be described in more detail below through experimental examples. However, the following embodiments are merely preferred embodiments for illustrative purposes and are not intended to limit the scope of the rights of this application. On the other hand, technical matters not described herein can be easily understood and performed by a person of ordinary skill who is skilled in the art of this application or a similar art.

[0052] Experimental Example 1. Production of valine fermentation liquid by culturing Corynebacterium microorganisms. In this experimental example, to produce granules containing L-valine, Corynebacterium glutamicum KCCM11338P (US 10072278 B2), one of the bacterial strains that produce L-valine, was cultured for 72 hours at approximately 30°C in a culture medium composed of 5% glucose, 2% ammonium sulfate, 0.1% monopotassium phosphate, 0.05% magnesium sulfate heptahydrate, 2.0% CSL (corn maceration solution), 200 μg / L biotin, and pH 7.2 to obtain a fermentation liquid with the following composition. The fermentation liquid contained the culture medium and microorganisms, and its moisture content and composition were analyzed. Table 2 shows the results of the compositional analysis of the valine fermentation liquid.

[0053] [Table 1]

[0054] Experimental Example 2. Comparative Analysis of Water Content in Amino Acid Wet Crystals Based on pH of Fermentation Liquid The fermentation liquid with an L-valine concentration of 80 g / L prepared in Experimental Example 1 was divided into 2 L portions, and sulfuric acid was added to produce process liquids with different pH levels (7.5 to 3.0). To precipitate valine crystals from the produced process liquids, a vacuum concentrator was used to concentrate the process liquid at a vacuum of 120 torr at a rate of 60 g / L / hr until the valine concentration reached 200 g / L. The concentrated crystal slurry containing valine crystals was separated into solid and liquid components using a basket separator to obtain L-valine crystals and mother liquor.

[0055] The water content in valine crystals based on the pH of the fermentation liquid was compared using LOD analysis.

[0056] [Table 2]

[0057] LOD moisture measurement results confirmed that when the pH of the fermentation liquid was between 3.0 and 6.0, the moisture content in the valine crystals was low. Furthermore, analysis of the viscosity of the concentrated slurry also confirmed that when the pH of the fermentation liquid was between 3.0 and 6.0, the viscosity of the concentrated slurry was low. Low viscosity of the concentrated slurry means that the valine crystals contained in the concentrated slurry were large in size, and not many fine crystals were formed. In contrast, in the case of the fermentation liquid with a pH of 7.0, where the concentrated slurry viscosity was high, it is analyzed that a large number of valine fine crystals were formed, resulting in high slurry viscosity. Therefore, it was confirmed that the pH of the fermentation liquid affects the formation of valine crystals. Specifically, it was confirmed that large valine crystals were formed within a specific pH range, resulting in low concentrated slurry viscosity and low moisture content in the separated crystals.

[0058] Experimental Example 3. Comparative Analysis of Water Content in Valine Crystals Based on Fermentation Liquid Concentration Rate (g / L / hr) In Experimental Example 1, the fermentation broth, which had an L-valine concentration of 80 g / L, was divided into 5 L portions. Sulfuric acid was then added to adjust the pH of the fermentation broth to 3.8. To precipitate valine crystals, a vacuum concentrator was used to concentrate the broth at a vacuum of 120 torr until the concentration reached 200 g / L. The concentration rate was varied for each batch, from 18 g / L / hr to 120 g / L / hr, and the physical properties of the concentrated crystal slurry obtained at each concentration rate were compared. The concentration rate was calculated by determining the concentration of valine (g / L) per hour based on the time it took for water to be removed from the initial valine concentration of 80 g / L in the fermentation broth until the valine concentration reached 200 g / L. The volume of condensed water and the time required for its removal were measured to calculate the concentration rate.

[0059] Furthermore, the concentrated crystalline slurry containing valine crystals was separated into solid and liquid components using a basket separator to obtain L-valine crystals and mother liquor. The water content in the valine crystals was compared at different concentration rates. The water content in the valine crystals at different fermentation liquor concentration rates was compared by LOD analysis.

[0060] [Table 3]

[0061] The moisture content of the LOD (Liquid Oxide) was measured, and it was confirmed that the moisture content in the crystals decreased as the concentration rate increased, indicating that the concentration rate affects valine crystal formation. In contrast, when the concentration rate was 18 g / L / hr, the crystals were produced in a gel-like form, making flow and separation difficult.

[0062] Experimental Example 4. Production of valine crystals from valine fermentation liquid. To adjust the pH of the fermentation broth to 3.8, sulfuric acid was added to 10 L of fermentation broth with an L-valine concentration of 80 g / L. To precipitate valine crystals, the fermentation broth was concentrated using a vacuum concentrator at a vacuum of 120 torr at a rate of 60 g / L / hr until the concentration reached 200 g / L.

[0063] The concentrated crystalline slurry was separated into solid and liquid components using a decanter to obtain 840 g of L-valine solid powder and 2850 mL of supernatant. At that time, it was confirmed that the water content in the valine crystals was 37% by weight, and the valine crystal yield was 80.0% based on the fermentation liquid.

[0064] Experimental Example 5. Production of valine granules from separated crystals Valine crystals were produced using the same method as in Experimental Example 4. The separated valine crystals were mixed with pre-dried valine seeds (valine content 75 w / w%) to produce crystals with moisture content ranging from 15% to 47%. Valine mixed granular crystals were then produced using a mixing granulator.

[0065] We confirmed that it is possible to produce mixed granules using a fully mixed granulator for crystals with a moisture content of 15% to 47%.

[0066] [Table 4]

[0067] From the above description, a person skilled in the art to which this application pertains will understand that this application can be implemented in other specific forms without altering its technical idea or essential features. In this regard, it should be understood that the embodiments described above are merely illustrative and not limiting. The scope of this application should be interpreted as encompassing all modified or altered forms derived from the meaning and scope of the claims, as described below, and their equivalent concepts, rather than from the above detailed description.

Claims

1. The step of preparing a fermentation solution containing valine; A step of adjusting the pH of the fermentation liquid; The step of concentrating the fermented liquid to prepare a concentrated fermented liquid; and A method for producing valine crystals, comprising the step of separating water-containing valine crystals from the concentrated fermentation liquid.

2. The method for producing valine crystals according to claim 1, wherein in the step of adjusting the pH of the fermentation liquid, the pH of the fermentation liquid is adjusted to be greater than 3.0 and less than 6.

0.

3. The valine crystal production method according to claim 1, wherein the step of concentrating the fermentation liquid to prepare a concentrated fermentation liquid is carried out by removing water from the fermentation liquid at a rate of 60 g / L / hr to 150 g / L / hr.

4. The method for producing valine crystals according to claim 1, wherein the valine crystals have a viscosity greater than 0 and less than 80 cp.

5. The method for producing valine crystals according to claim 1, wherein the valine crystals contain 10% to 55% by weight of water.

6. The step of preparing a fermentation solution containing valine; A step of adjusting the pH of the fermentation liquid; The step of preparing a concentrated fermented liquid by concentrating the aforementioned fermented liquid; A step of separating water-containing valine crystals from the concentrated fermentation liquid; The step of mixing the valine crystals with seeds to produce valine mixed granules; and A method for producing valine granules, comprising the step of drying the valine mixed granules.

7. The method for producing valine granules according to claim 6, wherein the mixed granules contain 10% to 50% by weight of moisture.

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