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

Abstract

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

Description

Technical Field

[0001] This application relates to a method for producing valine crystals and granules, which forms valine crystals and mixed granules with a low water content, reduces the amount of steam required for 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, after the fermentation process step, an amino acid separation or purification step for removing by-products is essential.

[0003] However, in amino acid products for feed, products with a high amino acid content (98% or more) are not required. Instead, it is more preferable to produce granular products that contain other nutritionally valuable components contained in the fermentation broth, do not generate waste in the purification step, and have a high content (70% or more).

[0004] In the prior art (Patent Document 1), in order to produce amino acid granular products for feed additives, a large amount of water in the fermentation broth was evaporated, and then granules were produced using a fluidized bed granulator. For amino acids with high solubility, even if the water is evaporated to a solid content of about 60 - 65% (water content 35 - 40%), crystals are not formed, so granulation is possible by the fluidized bed granulation method in which the fermentation broth is sprayed by a nozzle. However, valine has low solubility and crystals are formed even when the solid content in the fermentation broth is at a low level of about 12 - 15% (water content 85 - 88%). Therefore, the water content of the fermentation broth cannot be reduced to prevent crystal formation. Thus, 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; adding polyvinyl alcohol (PVA) to the fermentation liquid; and separating water-containing valine crystals from the 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; adding polyvinyl alcohol to the fermentation liquid; separating water-containing valine crystals from the fermentation liquid; mixing the valine crystals with seeds to produce 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; adding polyvinyl alcohol (PVA) to the fermentation liquid; and separating water-containing valine crystals from the 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; adding polyvinyl alcohol to the fermentation liquid; separating water-containing valine crystals from the fermentation liquid; mixing the valine crystals with seeds to produce mixed granules; and drying the valine mixed granules. [Effects of the Invention]

[0010] According to this application, by adjusting the pH of the fermentation liquid containing valine and adding PVA, the water content in valine crystals or valine mixed granules can be reduced, thereby reducing the energy required for drying. [Brief explanation of the drawing]

[0011] [Figure 1] This figure shows SEM images of valine crystals prepared according to one embodiment of the present invention. (a) and (b) show valine crystals prepared with no PVA added to the culture medium and with 2 wt% PVA added, respectively. [Modes for carrying out the invention]

[0012] These will be explained in detail below. Note that each description and embodiment disclosed in this application applies to other descriptions and embodiments. That is, any combination of the various elements disclosed in this application is included. Furthermore, this application is not limited to the following specific descriptions.

[0013] Furthermore, numerous papers and patent documents are referenced throughout this specification, and their citations are indicated. The disclosures of the cited papers and patent documents are incorporated in their entirety as references within this specification, thereby more clearly explaining the level of the art to which the present invention belongs and the content of the present invention.

[0014] Furthermore, any person with ordinary skill in the art would be able to recognize and confirm many equivalents of the specific embodiments of this application described herein using only ordinary experiments. Moreover, these equivalents are also intended to be included in this application.

[0015] As used in the specification and claims of this application, singular articles ("a," "an," and "the") include plural subjects unless otherwise specified. Unless otherwise specified, singular terms include plural subjects, and plural terms include singular subjects. Unless otherwise specified, in the specification and claims of this application, "or" is used to include "and / or."

[0016] In this application, "about" is used before a specific number. In this application, "about" includes not only the exact number that follows the term "about," but also a range that is approximately that number or close to it. Considering the context in which the number is used, it is possible to determine whether it is close to or approximately that specific number. For example, "about" indicates a range of -10% to +10% of a given number. Another example is that "about" indicates a range of -5% to +5% of a given number. However, it is not limited to these examples.

[0017] 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, adding polyvinyl alcohol (PVA) to the fermentation liquid, and separating water-containing valine crystals from the fermentation liquid. Each step will be described in detail below.

[0018] The step of preparing the fermentation liquid is the step of preparing a fermentation liquid containing valine. The valine contained in the fermentation liquid is an amino acid with low solubility in water. Here, low solubility does not mean that the solubility is below a specific standard. The fermentation liquid prepared in the above step may be a fermented product prepared by the metabolism of a bacterial strain. In this application, "fermented product" means the result of the enzymatic or metabolic decomposition of organic matter using microorganisms, for example, microorganisms that produce valine. For example, the fermented product includes the culture itself obtained by culturing microorganisms in a culture medium, or a concentrate, dried product, or freeze-dried product of the culture obtained by removing the bacterial strain therefrom. Furthermore, the fermentation liquid may include the entire fermented product containing valine, or it may be a fermented product containing valine from which impurities have been removed.

[0019] The fermentation liquid mainly consists of valine, but may also contain other components. For example, other amino acids, organic acids, and inorganic substances may be supplied to the fermentation liquid in addition to valine, and these may be dissolved in water. The concentration of valine in the fermentation liquid may be about 1 g / L to about 200 g / L. However, the valine concentrations mentioned above are merely examples, and fermentation liquids with concentrations outside the range mentioned above may be used in the valine crystal production method according to one embodiment of this application.

[0020] In the step of preparing the fermentation broth of the present application, the "microorganism that produces valine" or "microorganism having the ability to produce valine" includes all wild-type microorganisms that naturally have the ability to produce valine, and microorganisms in which the ability to produce valine has been imparted to a parent strain that naturally or artificially has no ability to produce valine through genetic modification. It is a microorganism in which a specific mechanism has been weakened or strengthened due to reasons such as insertion of an external gene or enhancement or inactivation of the activity of an endogenous gene, and may be a microorganism in which genetic modification (modification) has been carried out for the production of an amino acid, namely valine. Specifically, in the present application, the microorganism that produces valine or the microorganism having the ability to produce valine may be a microorganism in which a part of the gene in the biosynthetic pathway of the target product valine has been enhanced or weakened, or a microorganism in which a part of the gene in the valine degradation pathway has been enhanced or weakened. When the valine-producing ability of the microorganism of the present application is "enhanced" or "improved", it means that the valine-producing ability of the microorganism of the present application is improved compared to other microorganisms, parent strains or unmodified microorganisms other than the microorganism of the present application. For example, the microorganism of the present application has improved by about 1% or more, 10% or more, 100% or more, 200% or more, 500% or more, 1000% or more, 1100% or more, 1200% or more, 1300% or more compared to the valine-producing ability of other microorganisms, or has improved by about 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, 13 times or more, but is not limited thereto. The above-mentioned "about" includes all ranges such as ±0.5, ±0.4, ±0.3, ±0.2, ±0.1, etc., and any numerical value within a range equivalent to or of the same degree as the numerical value following the term "about" may be used, but is not limited thereto.

[0021] The aforementioned microorganisms used in the step of preparing the fermentation liquid of this application are at least one selected from the group consisting of the yeast Candida famata, the ascomycetes Eremothecium ashbyii and Ashbya gossypii, the bacterium Bacillus subtilis, and microorganisms of the genus Corynebacterium sp.

[0022] For example, if the microorganism used in the step of preparing the fermentation liquid of this application is a microorganism of the genus Corynebacterium, then the microorganism is specifically Corynebacterium glutamicum, Corynebacterium crudilactis, Corynebacterium deserti, Corynebacterium efficiens, Corynebacterium callunae, Corynebacterium stationis, Corynebacterium singulare, Corynebacterium halotolerans, Corynebacterium striatum These include Corynebacterium striatum, Corynebacterium ammoniagenes, Corynebacterium pollutisoli, Corynebacterium imitans, Corynebacterium testudinoris, Corynebacterium crenatum, or Corynebacterium flavescens, and more specifically, Corynebacterium glutamicum, but are not limited to these.

[0023] 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. Various studies have been conducted to develop highly efficient production microorganisms and fermentation process technologies for producing the above-mentioned L-amino acids and other useful substances. For example, an approach specific to a target substance is mainly used, such as increasing the expression of a gene encoding an enzyme involved in the biosynthesis of L-valine or removing a gene unnecessary for biosynthesis. In the present application, a fermentation broth containing an amino acid may be prepared using a strain of the genus Corynebacterium.

[0024] According to one specific example of the present application, Corynebacterium glutamicum used for preparing a fermentation broth containing valine is a strain overexpressing L-valine biosynthesis in which the L-valine biosynthesis regulatory site of Corynebacterium glutamicum ATCC13032 is inactivated, but is not limited thereto. Alternatively, the Corynebacterium glutamicum may be a strain transformed with the pDZDvalL, pDZDvalP, or pDZDvalS vector using the chromosome of Corynebacterium glutamicum KCCM11201P, Corynebacterium glutamicum KCCM11336P, Corynebacterium glutamicum KCCM11337P, Corynebacterium glutamicum KCCM11338P, or Corynebacterium glutamicum KCCM11201P_DvalA as a template. In addition, the Corynebacterium glutamicum may be a Corynebacterium glutamicum ATCC13032_DvalL, Corynebacterium glutamicum ATCC13032_DvalP, or Corynebacterium glutamicum ATCC13032_DvalS strain, but is not limited thereto, and any microorganism that produces a fermentation broth containing valine may be used (Patent Document 2).

[0025] The step of preparing the fermentation liquid may further include the step of culturing the "valine-producing microorganisms." The culture of the microorganisms can be carried out in suitable culture media and culture conditions known in the art. Such a culture process can be easily adjusted and used by those skilled in the art depending on the selected strain. Specifically, the culture may be batch, continuous, or fed-batch culture, but is not limited to these.

[0026] In this application, "culture medium" refers to a substance mixed mainly with nutrients necessary for culturing the microorganisms, supplying nutrients and growth factors, including water, which are essential for survival and growth. Specifically, the culture medium and other culture conditions used for culturing the microorganisms in this application may be any that are normally used for culturing microorganisms, and the microorganisms in this application can be cultured under aerobic conditions by adjusting the temperature, pH, etc., in a normal culture medium containing a suitable carbon source, nitrogen source, phosphorus source, inorganic compounds, amino acids and / or vitamins.

[0027] In this application, "valine-containing fermented liquid" is used interchangeably with "valine-containing fermented liquid" or "valine fermented liquid."

[0028] Next, the step of adjusting the pH of the fermentation liquid is performed. Here, the pH of the fermentation liquid may be adjusted to a range of approximately greater than 3.0 but less than 6.0. In some cases, the pH of the fermentation liquid may be adjusted to approximately 3.5 to less than 6.0, approximately 4.0 to less than 6.0, approximately 4.5 to less than 6.0, approximately 5.0 to less than 6.0, approximately 5.5 to less than 6.0, approximately greater than 3.0 to 5.5, approximately 3.5 to 5.5, approximately 4.0 to 5.5, approximately 4.5 to 5.5, approximately 5.0 to 5.5, approximately 3.0 to 5.0, approximately 3.5 to 5.0, approximately 4.0 to 5.0, approximately 4.5 to 5.0, approximately greater than 3.0 to 4.5, approximately 3.5 to 4.5, approximately 4.0 to 4.5, approximately greater than 3.0 to 4.0, approximately 3.5 to 4.0, or greater than 3.0 to 3.5.

[0029] By adjusting the pH of the fermentation liquid, the size and hardness of the valine crystals formed in the subsequent concentration step can be controlled. Specifically, by adjusting the pH of the fermentation liquid to the above range and then performing concentration, large and hard valine crystals are formed, thus reducing the water content of the separated valine crystals. If the pH of the fermentation liquid is outside the above range, the size of the valine crystals precipitated after concentration will be small, making it difficult to separate the valine crystals from the yeast 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.

[0030] In the step of adjusting the pH of the fermentation liquid, pH adjustment may be performed using ordinary acidic or basic substances. However, the substances added to the fermentation liquid for pH adjustment should be selected from those that do not affect the physical properties or chemical structure of the valine contained in the fermentation liquid. Furthermore, considering that valine products are used for food or animal feed, edible acidic or basic substances may be added.

[0031] After adjusting the pH as 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 may be heated to approximately 60°C to 90°C.

[0032] After performing the step of adjusting the pH of the fermentation liquid, the step of adding polyvinyl alcohol (PVA) to the prepared fermentation liquid is performed. For example, in the manufacturing method of this application, the addition of polyvinyl alcohol is for adjusting the crystallinity of the resulting L-valine crystals, and by adding polyvinyl alcohol, it is possible to produce L-valine crystals with uniform and excellent crystal properties without being affected by the concentration rate during concentration.

[0033] Here, the polyvinyl alcohol may be added in an amount of 0.1 wt% to 5 wt% relative to the total weight of the fermentation liquid. In some cases, the polyvinyl alcohol may be added in an amount of 0.3 wt% to 4 wt%, 0.5 wt% to 3 wt%, 0.5 wt% to 2.5 wt%, 1 wt% to 3 wt%, 1 wt% to 2.8 wt%, 1.5 wt% to 3 wt%, 1.5 wt% to 2.5 wt%, 1 wt% to 2.5 wt%, or 1.8 wt% to 2.3 wt%.

[0034] For example, in the manufacturing method of this application, L-valine crystals produced by adding PVA to the culture medium and concentrating it may have a water content in the crystals that is 8% to 40% lower than crystals produced by a manufacturing method in which PVA is not added in the second step.

[0035] For example, the manufacturing method of this application may further include a concentration step after the step of adding polyvinyl alcohol to the fermentation liquid. The concentration step is for producing L-valine crystals, and the concentration is carried out to a solid content of 15-30%, but is not limited thereto.

[0036] In the concentration step, water is removed from the fermentation liquid to precipitate valine in crystalline form. Concentration can be carried out by various methods. Concentration can be carried out in a conventional concentrator (e.g., a paddle dryer, slurry dryer, vacuum concentrator, forced-circulation concentrator, thin-film concentrator, rotary concentrator, etc.) as appropriate by those skilled in the art.

[0037] In the concentration step, concentration may be carried out by removing water from the fermentation liquid at a rate of 30 g / L / hr to 150 g / L / hr (meaning that 30 g to 150 g of water per liter of fermentation liquid is removed in one hour). In some cases, concentration may be carried out by removing water from the fermentation liquid 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. Concentration at the aforementioned rates forms relatively large valine crystals, which can be easily separated from the fermentation liquid. In addition, this reduces the water content in the valine crystals.

[0038] Next, a step is performed to separate the valine crystals containing water from the fermentation liquid. The valine crystals may be valine crystals in which the water content in the crystal has been reduced by concentration.

[0039] In the separation step, water-containing valine crystals are separated from the fermentation liquid. Here, solid-liquid separators such as vacuum membrane filters, pressure membrane filters, and centrifuges may be used. However, the means described above are illustrative, and the means for performing the separation step are not limited to the above examples.

[0040] In the separation step, the mother liquor remaining after valine crystal separation may be used again for concentration. Therefore, valine that does not form water-containing crystals in the concentration step, or crystals below a certain size that precipitate and remain in the mother liquor without being separated in the valine crystal separation step, can be recycled. Furthermore, after mother liquor circulation, if necessary, further steps such as heating the fermentation liquid may be performed to dissolve the valine precipitated in the form of fine crystals back into the fermentation liquid.

[0041] According to the method for producing valine crystals according to one aspect of the present application described above, valine crystals with low water content and easy separation can be obtained by adjusting the pH of the fermentation liquid containing valine and adding an appropriate amount of PVA to the fermentation liquid.

[0042] Valin crystals prepared according to one aspect of this application may have a viscosity greater than 0 and less than 80 cp. In some cases, the viscosity of the valine crystals may be greater than 20 and less than 80 cp, greater than 40 and less than 80 cp, greater than 60 and less than 80 cp, greater than 0 and less than 70 cp, greater than 20 and less than 70 cp, greater than 40 and less than 70 cp, greater than 60 and less than 70 cp, greater than 0 and less than 50 cp, greater than 20 and less than 50 cp, greater than 40 and less than 50 cp, greater than 0 and less than 30 cp, greater than 20 and less than 30 cp, or greater than 0 and less than 10 cp. Valin crystals having a viscosity in the above ranges have a low water content and an appropriate size, so they can be easily separated from the mother liquor.

[0043] Valine crystals prepared according to one aspect of this application may contain 10% to 55% by weight of water. In some cases, 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 as is without a separate drying step, or after only a slight drying, thus saving energy required for the process.

[0044] Furthermore, the manufacturing method of this application may further include a drying step, a sieving step, or both, after the step of separating the L-valine crystals. Each of the above steps may be carried out using any method known in the art (for example, Patent Document 3). In addition, specific conditions may be changed as appropriate to optimize the process, but are not limited thereto.

[0045] This application provides L-valine crystals containing polyvinyl alcohol and L-valine, wherein, during concentration, the water content in the separated crystals is reduced by 5-40% compared to L-valine crystals produced without using polyvinyl alcohol.

[0046] For example, the L-valine crystal may be in the form of spherical particles.

[0047] Specifically, the L-valine crystals of this application may be manufactured by the method described above. Furthermore, while the L-valine crystals of this application are used for animal feed or as a feed additive, their uses are not limited to these.

[0048] A method for producing valine granules includes the steps of: preparing a fermentation liquid containing valine; adjusting the pH of the fermentation liquid; adding polyvinyl alcohol to the fermentation liquid; separating water-containing valine crystals from the fermentation liquid; mixing the valine crystals with seeds to produce mixed granules; and drying the valine mixed granules.

[0049] Here, the steps of preparing the fermentation liquid, adjusting the pH of the fermentation liquid, adding polyvinyl alcohol to the fermentation liquid, and separating the valine crystals are carried out in the same way as in the valine crystal production method described above. Therefore, in order to avoid repetition of explanations, the following will focus on the steps of mixing the valine crystals with seeds to produce mixed granules and drying the mixed granules.

[0050] In the step of preparing mixed granules, the valine crystals obtained in the step of separating the valine crystals are mixed with seeds for the production of valine granules.

[0051] In the step of preparing mixed granules, the seed used 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. When the seed comes into contact with the fermentation liquid, solid components present in the fermentation liquid bind to the seed, forming agglomeration and thus granules.

[0052] The seeds used in the step of preparing 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 to these. The particle size of the seeds used will affect the productivity of the granule production according to this application, so a person skilled in the art can appropriately select it considering the desired moisture content, etc.

[0053] In the step of producing mixed granules, a mixing-type granulator may be used. The mixing-type granulator may produce granules by simultaneously injecting seeds into the granulator at a constant rate using a feeder and supplying valine crystals obtained in the separation step described above. The mixing-type granulator may include a feeder for supplying seeds internally and a component for supplying valine crystals. Furthermore, the mixing-type granulator may be equipped with a gas nozzle for generating airflow inside the chamber, a paddle for mixing the seeds and valine crystals supplied into the chamber, etc. The seeds and valine crystals that flow into the chamber may solidify together to form valine mixed granules.

[0054] According to one aspect of this application, valine mixed granules with low water content and large crystal size may be produced by mixing seeds with valine crystals containing water. As mentioned above, according to this application, large valine crystals precipitate, and these large valine crystals can be easily separated from the fermentation liquid, so the water content in the valine crystals is relatively low. Furthermore, in the step of producing the mixed granules, valine crystals with low water content and seeds are granulated in a mixing granulator, so the produced valine mixed granules also have low water content and large crystal size.

[0055] Here, "granules" refers to macroscopic particles, which are relatively large permanent aggregates formed by the aggregation of small particles, such as powder, and specifically to particles with an average particle size of 50 μm to 5 mm, 75 μm to 4 mm, or 100 μm to 3 mm.

[0056] The valine mixed granules obtained in the step of preparing 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 is a lower moisture content compared to valine granules obtained by conventional techniques. Therefore, the amount of energy required to dry the valine mixed granules obtained by this application can be reduced.

[0057] Next, a drying step is performed to dry the valine-mixed granules.

[0058] In the drying step, the valine-mixed granules obtained as described above are dried, but any drying method is acceptable.

[0059] One aspect of this application provides a valine product containing valine mixed granules. In this application, "valine product" means a product made by processing valine contained in a fermentation liquid into various dosage forms. For example, the valine product may be a valine-containing mixture in granule form. However, the dosage form of the valine product may be changed as needed, without departing from the spirit of the present invention. Furthermore, as described above, further post-processing may be carried out to realize various dosage forms of valine products. The valine product described above may be used as an additive in animal feed, etc., and may be used for any purpose.

[0060] According to this application, valine-containing fermentation liquid can be concentrated to separate valine crystals, and the separated valine 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. For example, according to this application, the moisture content in the valine-mixed granules can be further reduced by adjusting the pH of the fermentation liquid or by adjusting the concentration rate.

[0061] The L-valine crystals or granules of this application are suitable for use as feed additives in the manufacture of animal feed. For example, the L-valine crystals as a feed additive can be part of an animal feed premix or a precursor of animal feed, and can be mixed with feed materials on their own. The feed composition containing the L-valine crystals or granules may be administered to animals alone or in combination with other feed additives in an edible carrier. Furthermore, the feed composition can be easily administered to animals as a top dressing, by mixing them directly into animal feed, or in an oral dosage form separate from the feed. [Examples]

[0062] The present application will be described in more detail below with reference to examples. However, these examples are merely illustrative of the present application and the present application is not limited thereto. Each description and embodiment disclosed in this application also applies to other descriptions and embodiments. That is, any combination of the various elements disclosed in this application is included in this application. Furthermore, many papers and patent documents are referenced throughout this specification, and their citations are indicated. The disclosures of the cited papers and patent documents are incorporated in their entirety as references in this specification, thereby more clearly explaining the level of the art to which the present invention belongs and the content of the present invention.

[0063] Experimental Example 1: Preparation of valine fermentation broth by culturing Corynebacterium microorganisms In this experimental example, in order to produce granules containing L-valine, Corynebacterium glutamicum KCCM11338P (Patent Document 2), one of the bacterial strains that produces L-valine, was cultured for 72 hours at approximately 30°C in a culture medium with the following composition: glucose 5%, ammonium sulfate 2%, potassium dihydrogen phosphate 0.1%, magnesium sulfate heptahydrate 0.05%, CSL (corn maceration solution) 2.0%, biotin 200 μg / L, and pH 7.2, to obtain a fermentation liquid with the following composition. The fermentation liquid contained the culture medium and microorganisms, and moisture content and compositional analysis were performed using this liquid. Table 1 shows the results of the compositional analysis of the valine fermentation liquid.

[0064] [Table 1]

[0065] Experimental Example 2: Comparison of water content in valine crystals based on the pH of the fermentation liquid. The fermentation liquid with an L-valine concentration of 80 g / L prepared in Experimental Example 1 described above was divided into 2 L portions, and sulfuric acid was then added to prepare process liquids at various pH levels (7.5 to 3.0). To precipitate valine crystals from the prepared process liquids, the liquids were concentrated using a vacuum concentrator at a vacuum of 120 torr at a rate of 60 g / L / hr until the valine concentration reached 200 g / L. 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.

[0066] The water content in valine crystals at various pH levels of the fermentation liquid was compared using LOD analysis (Table 2).

[0067] [Table 2]

[0068] LOD moisture measurement results confirmed that the moisture content in valine crystals was lowest when the pH of the fermentation liquid was between 3.0 and 6.0. Furthermore, analysis of the concentrated slurry viscosity also confirmed that the concentrated slurry viscosity was very low when the pH of the fermentation liquid was between 3.0 and 6.0. Low concentrated slurry viscosity means that the valine crystals contained in the concentrated slurry were large, and not many fine crystals were formed. In contrast, the high viscosity of the concentrated slurry in the fermentation liquids at pH 7.0, pH 6.0, and pH 3.0 was attributed to the formation of many valine fine crystals.

[0069] 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, the viscosity of the concentrated slurry was low, and the moisture content of the separated crystals was low.

[0070] Experimental Example 3: Comparison of water content in valine crystals depending on the type of additive. To confirm the effect of the presence and / or type of additives in the valine crystal production process from a valine-containing culture medium, culture media were prepared by adding 2 wt% (value relative to the weight of L-valine) of polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), and monosodium glutamate (MSG) to the L-valine culture medium prepared in Experimental Example 1 by adding sulfuric acid to adjust the pH to 3.8. These culture media were concentrated using a vacuum concentrator at a vacuum of 120 torr and a rate of 30 g / L / hr until the concentration reached 200 g / L. Next, solid-liquid separation was performed using a basket separator at 1800 rpm for 10 minutes, and L-valine crystals were obtained from the concentrated culture media as described above. The water content of the separated L-valine crystals was calculated by LOD analysis and compared (Table 3).

[0071] [Table 3]

[0072] As shown in Table 3, no significant change in the water content of the crystals was observed when other additives were used. However, the crystals obtained using the PVA process showed a reduction in water content of more than 30% compared to the control group without additives. This indicates that adding PVA to the culture medium before concentration is effective in reducing the amount of water contained in the final valine crystals.

[0073] Experimental Example 4: Comparison of water content in valine crystals based on the amount of PVA used. Using PVA, which showed the best effect in Experimental Example 3, we varied the amount of additive used to confirm its effect at each dosage. Specifically, we prepared culture solutions with additive amounts of 0.5, 1.5, 2.0, and 2.5 wt% (value relative to the weight of L-valine), concentrated and separated them in the same manner as in Experimental Example 3 to obtain crystals, and calculated the water content of the separated L-valine crystals by LOD analysis (Table 4).

[0074] [Table 4]

[0075] In all samples tested across the entire range of PVA input, the water content in the crystals decreased compared to the control group sample without PVA input (0 wt%), with a reduction rate of approximately 9.1% to 34.7% observed.

[0076] Furthermore, the morphology of the crystals formed in the 2wt% PVA sample and the control group without PVA was observed using SEM (30x magnification, JEOL, JCM-6000PLUS). As a result, plate-like fine powder crystals were formed in the control group without PVA, while larger, nearly spherical particles were formed in the group with 2wt% PVA (Figure 1).

[0077] Experimental Example 5. Preparation of valine granules from separated crystals Similar to Experimental Example 4, valine crystals were prepared, and the separated valine crystals were mixed with pre-dried valine seeds (valine content 75%) to produce crystals with moisture content ranging from 15% to 47%. Subsequently, valine mixed granular crystals were produced using a mixing granulator.

[0078] It was confirmed that mixed granules could be produced using a mixed-type granulator for all crystals with a moisture content of 15% to 47%.

[0079] [Table 5]

[0080] From the above explanation, 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. It should be understood that the above embodiments are merely illustrative and not limiting. This application should be interpreted as including all modified or altered forms derived from the meaning and scope of the claims and their equivalent concepts, rather than the specification.

Claims

1. The steps include preparing a fermentation solution containing valine, The steps include adjusting the pH of the fermentation liquid, The steps include adding polyvinyl alcohol (PVA) to the fermentation liquid, The step includes separating water-containing valine crystals from the fermentation liquid. Method for manufacturing valine crystals.

2. In the step of adjusting the pH of the fermentation liquid, the pH of the fermentation liquid is adjusted to be greater than 3 but less than 6. The method for producing valine crystals according to claim 1.

3. The polyvinyl alcohol is added in an amount of 0.1 wt% to 5 wt% relative to the total weight of the fermentation liquid. The method for producing valine crystals according to claim 1.

4. The step of adding polyvinyl alcohol to the fermentation liquid further includes the step of concentrating the fermentation liquid. The method for producing valine crystals according to claim 1.

5. The aforementioned concentration is carried out by removing water from the fermentation liquid at a rate of 30 g / L / hr to 150 g / L / hr. The method for producing valine crystals according to claim 4.

6. The valine crystal has a viscosity greater than 0 and less than 80 cP. The method for producing valine crystals according to claim 1.

7. The valine crystals contain 10 wt% to 55 wt% of water. The method for producing valine crystals according to claim 6.

8. The valine crystals are in the form of spherical particles. The method for producing valine crystals according to claim 1.

9. The steps include preparing a fermentation solution containing valine, The steps include adjusting the pH of the fermentation liquid, The steps include adding polyvinyl alcohol to the fermentation liquid, The steps include separating water-containing valine crystals from the fermentation liquid, The steps include: mixing the valine crystals with seeds to produce mixed granules; The step of drying the valine-mixed granules is included. Method for manufacturing valine granules.

10. The step of adding polyvinyl alcohol to the fermentation liquid further includes the step of concentrating the fermentation liquid. The method for producing valine granules according to claim 9.

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