Preparation Process for L-Valine Crystal and / or Granule Using a Step of Adjusting pH and Adding PVA

Abstract

The present application relates to a method for manufacturing valine crystals and / or valine granules using pH adjustment and PVA addition.

Description

Technology Field

[0001] The present application relates to a method for manufacturing valine crystals and granules that can reduce the amount of steam required during the production of valine granules and improve the efficiency of valine granule production by forming valine crystals and mixed granules with low moisture content. Background Technology

[0003] To obtain high-purity amino acids through fermentation, a separation or purification step of the amino acids is essential to remove byproducts following the fermentation process.

[0004] However, for amino acid products for animal feed, a product with a high amino acid content (98% or more) is not required, and it may be more appropriate to produce a granulated product with a high content (70% or more) that contains other nutritionally valuable components included in the fermented liquid without generating waste during the purification stage.

[0005] In the existing technology (US 7,514,111 B2), to manufacture amino acid granules for feed additives, a large amount of water is evaporated from the fermentation liquid, and granules are produced using a fluidized bed granulator. For highly soluble amino acids, crystals do not form even when water is evaporated to a solid content of approximately 60–65% (moisture content 35–40%), making granulation possible using the fluidized bed granulation method where the fermentation liquid is sprayed through a nozzle. However, valine has low solubility, so crystals form even when the solid content in the fermentation liquid is as low as approximately 12–15% (moisture content 85–88%); therefore, the moisture content of the fermentation liquid cannot be lowered to prevent crystal formation. Consequently, a large amount of water must be evaporated during the drying process, requiring significant energy consumption. Prior art literature

[0007] US 7,514,111 B2US 10,072,278 B2 The problem to be solved

[0008] 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 valine crystals containing water from the fermentation liquid.

[0009] In addition, the present application aims to provide a method for manufacturing 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 valine crystals containing water from the fermentation liquid; mixing the valine crystals with a seed to produce mixed granules; and drying the valine mixed granules. means of solving the problem

[0011] This is explained in detail as follows. Meanwhile, each description and embodiment disclosed in this application may be applied 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 scope of this application should not be considered limited by the specific descriptions provided below.

[0012] Furthermore, numerous papers and patent documents are referenced and cited throughout this specification. The disclosures of the cited papers and patent documents are incorporated by reference into this specification in their entirety to more clearly explain the state of the art to which the present invention pertains and the content of the present invention.

[0014] A method for preparing valine crystals according to the present application comprises 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 valine crystals containing water from the fermentation liquid. Each step is described in detail below.

[0016] The step of preparing the fermentation liquid is to prepare 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 strain. In this application, the term "fermented product" may refer to the result of the enzymatic or metabolic decomposition of organic matter using microorganisms. For example, the fermented product may include 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 strain from it. Furthermore, in this case, the fermentation liquid may include the entire fermented product containing valine, or may be a fermented product containing valine from which impurities have been removed.

[0017] The fermentation liquid may contain valine as the main component, but may also include other components. For example, other amino acids, organic acids, and inorganic substances other than valine may be provided in the fermentation liquid, 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 above-described concentration of valine is merely exemplary, and a fermentation liquid with a concentration other than that described in the above-described range may also be used in the method for producing valine crystals according to one embodiment of the present application.

[0018] The "microorganism producing valine" or "microorganism producing valine or a target product" used in the step of preparing the fermentation liquid includes all wild-type microorganisms or microorganisms that have undergone natural or artificial genetic modification, and may be microorganisms in which specific mechanisms are weakened or strengthened due to causes such as the insertion of external genes or the enhancement or inactivation of the activity of endogenous genes, and may be microorganisms that include genetic modification for the production of a target protein or valine.

[0019] The valine-producing microorganism of the present application may be, but is not limited to, a microorganism that naturally possesses the ability to produce valine, or a parent strain that lacks the ability to produce valine but has been endowed with the ability to produce valine. Specifically, the microorganism that produces valine or a target product in the present application, or the microorganism that possesses the ability to produce valine or a target product, may be a microorganism in which a portion of a gene within the biosynthetic pathway of the target protein or target product is strengthened or weakened, or a portion of a gene within the degradation pathway of the target protein or target product is strengthened or weakened. "Strengthening" or "increasing" the valine-producing ability of the microorganism of the present application means that the valine-producing ability of the microorganism of the present application is improved compared to other microorganisms, parent strains, or non-modified microorganisms other than the microorganism of the present application. For example, the microorganism of the present application may be 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, or 1300% or more compared to the valine production capacity of other microorganisms, and may be 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, or 13 times or more, but is not limited thereto. The above term "about" includes a range that encompasses all of ±0.5, ±0.4, ±0.3, ±0.2, ±0.1, etc., and includes all numerical values ​​in a range equivalent to or similar to the numerical value following the term "about," but is not limited thereto.

[0020] The aforementioned microorganism used in the step of preparing the fermentation liquid is the yeast Candida farma ( Candida famata ), the ascomycete Eremothesium eshvy ( Eremothecium ashbyii ) and Eshvia Gossippi( Ashbyagossypii ), the bacterium Bacillus subtilis ( Bacillus subtilis ), genus Corynebacterium ( Corynebacterium sp. It may be at least one selected from a group of microorganisms.

[0021] If the microorganism used in the step of preparing the fermentation liquid is a microorganism of the genus Corynebacterium, the microorganism is specifically Corynebacterium glutamicum ( Corynebacterium glutamicum ), Corynebacterium crudilactis( Corynebacterium crudilactis ), Corynebacterium deserti( Corynebacterium deserti ), Corynebacterium epiphysiens( Corynebacterium efficiens ), Corynebacterium calunae( Corynebacterium callunae ), Corynebacterium stationaryis( Corynebacterium stationis ), Corynebacterium singulare( Corynebacterium singulare ), Corynebacterium halotolerans( Corynebacterium halotolerans ), Corynebacterium striatum ( Corynebacterium striatum ), Corynebacterium ammoniagenes( Corynebacterium ammoniagenes ), Corynebacterium pollatisoli ( Corynebacterium pollutisoli ), Corynebacterium imitans( Corynebacterium imitans ), Corynebacterium testudinoris( Corynebacterium testudinoris ) Corynebacterium crenatum( Corynebacterium crenatum ), or Corynebacterium flavescens ( Corynebacterium flavescens It could be, and more specifically, Corynebacterium glutamicum ( Corynebacterium glutamicum It may be, but is not limited to.

[0023] According to one aspect of the present application, the "valine-producing microorganism" used to prepare a fermentation liquid containing valine may be an L-valine biosynthetic overexpressing strain in which the L-valine biosynthetic regulatory site is inactivated by transforming Corynebacterium glutamicum ATCC13032. For example, the "valine-producing microorganism" may be a strain transformed with the pDZDvalL, pDZDvalP, or pDZDvalS vectors using the chromosomes of Corynebacterium glutamicum KCCM11201P, Corynebacterium glutamicum KCCM11336P, Corynebacterium glutamicum KCCM11337P, Corynebacterium glutamicum KCCM11338P, or Corynebacterium glutamicum KCCM11201P_DvalA as a template. According to a more specific example, "microorganisms that produce valine" may be strains of Corynebacterium glutamicum ATCC13032_DvalL, Corynebacterium glutamicum ATCC13032_DvalP, and Corynebacterium glutamicum ATCC13032_DvalS (US 10,072,278 B2).

[0024] The step of preparing the fermentation liquid may further include a step of culturing "microorganisms that produce valine." The cultivation of microorganisms may be carried out according to suitable media and culture conditions known in the art. This cultivation process can be easily adjusted and used by those skilled in the art depending on the selected strain. Specifically, the cultivation may be batch, continuous, or fed-batch, but is not limited thereto.

[0025] In this application, the term "medium" refers to a substance mixed with nutrients as the main component required to culture the microorganism, and supplies nutrients and growth factors, including water, which is indispensable for survival and growth. Specifically, the medium and other culture conditions used for culturing the microorganism of this application may be any medium used for culturing microorganisms without special limitations, provided that the microorganism of this application is cultured under aerobic conditions while controlling the temperature, pH, etc., in a conventional medium containing a suitable carbon source, nitrogen source, phosphorus, inorganic compounds, amino acids, and / or vitamins.

[0026] The term "fermented liquid containing valine" in this application may be used interchangeably with "fermented liquid containing valine" or "valine fermented liquid."

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

[0029] By adjusting the pH of the fermentation liquid, the size and hardness of the valine crystals formed during the subsequent concentration step can be controlled. Specifically, when concentration is performed after adjusting the pH of the fermentation liquid to the aforementioned range, large and hard valine crystals can be formed, thereby reducing the moisture 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 may be small, making it difficult to separate the valine crystals from the mother liquor. Furthermore, since a relatively large amount of water is separated along with the valine crystals, a significant amount of energy is required for subsequent drying.

[0030] In the step of adjusting the pH of the fermentation liquid, pH adjustment can be performed using conventional acidic or basic substances. However, the substance added to the fermentation liquid for pH adjustment may be determined only to the extent that it does not affect the physical properties or chemical structure of the valine contained in the fermentation liquid. Additionally, considering that the valine product may be used for food or animal feed, edible acidic or basic substances may be added.

[0031] After the pH adjustment described above, if necessary, procedures such as heating the fermentation liquid may be performed to completely dissolve any valine that may have precipitated in the fermentation liquid. For example, the fermentation liquid may be heated to about 60°C to about 90°C.

[0033] After performing the step of adjusting the pH of the fermentation liquid, a step of adding polyvinyl alcohol (PVA) to the prepared fermentation liquid is performed. For example, in the manufacturing method of the present application, the addition of polyvinyl alcohol is intended to control the crystallinity of the L-valine crystals produced, and by adding polyvinyl alcohol, L-valine crystals having uniform and excellent crystal characteristics can be produced without being affected by the concentration rate during concentration.

[0034] At this time, the polyvinyl alcohol may be added in an amount of 0.1 wt% to 5 wt% based on the total weight of the fermentation liquid. Depending on the case, 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%.

[0035] For example, L-valine crystals produced by adding PVA to a culture medium and concentrating it according to the manufacturing method of the present application may be crystals with a moisture content reduced by 8% to 40% compared to crystals produced according to a manufacturing method in which PVA is not added in the second step.

[0037] For example, in the manufacturing method of the present application, a step of concentrating may be additionally included after the step of adding polyvinyl alcohol to the fermentation liquid. The above-mentioned concentrating step is for producing L-valine crystals, and the concentration can be performed with a solid content of 15 to 30%, but is not limited thereto.

[0038] In the concentration step, water is removed from the fermentation liquid to precipitate valine in crystalline form. Concentration can be performed in various ways. Concentration can be performed in a conventional concentrator (e.g., paddle dryer, slurry drying equipment, vacuum concentrator, forced circulation concentrator, thin film concentrator, or rotary concentrator, etc.) at the appropriate choice of a person skilled in the art.

[0039] In the concentration step, concentration may be performed by removing moisture from the fermentation liquid at a rate of 30 g / L / hr to 150 g / L / hr (meaning removing 30 g to 150 g of moisture per liter of fermentation liquid for 1 hour). In some cases, concentration may be performed by removing moisture 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 affecting the size of the valine crystals. When concentrated at the above-described rates, relatively large valine crystals are formed, and the valine crystals can be easily separated from the mother liquor of the fermentation liquid. Additionally, the moisture content within the valine crystals is reduced accordingly.

[0041] Next, a step of separating water-containing valine crystals from the fermentation liquid is performed. The valine crystals may be valine crystals in which the water content within the crystals has been reduced by concentration.

[0042] In the separation step, water-containing valine crystals are separated from the fermentation liquid, and solid-liquid separators such as vacuum membrane filtration devices, pressurized membrane filtration devices, and centrifugal devices may be used. However, the means described above are exemplary, and the means for performing the separation step are not limited to the examples described above.

[0044] The mother liquor remaining after the separation of valine crystals in the separation step can be reused for concentration. Accordingly, valine that failed to form water-containing crystals during the concentration step, or valine that remained in the mother liquor without being separated during the crystal separation step due to precipitation as crystals smaller than a certain size, can be recycled. Additionally, after the mother liquor circulation, further processes, such as heating the fermentation liquid, may be performed as needed to dissolve the valine precipitated in the form of fine crystals back into the fermentation liquid.

[0045] According to the method for manufacturing valine crystals according to one embodiment of the present application described above, by adjusting the pH of a fermentation liquid containing valine and adding an appropriate amount of PVA to the fermentation liquid, valine crystals with low moisture content and easy separation can be obtained.

[0046] The valine crystals prepared according to one embodiment of the present 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 70 cp, greater than 20 and 70 cp, greater than 40 and 70 cp, greater than 60 and 70 cp, greater than 0 and 50 cp, greater than 20 and 50 cp, greater than 40 and 50 cp, greater than 0 and 30 cp, greater than 20 and 30 cp, or greater than 0 and 10 cp. The valine crystals having a viscosity within the above-described range can be easily separated from the mother liquor because they have a low water content and an appropriate size.

[0047] A valine crystal prepared according to one embodiment of the present application may contain 10% to 55% by weight of moisture. In some cases, the valine crystal 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 moisture. Since valine crystals having the aforementioned moisture content have a relatively low moisture content, they can be used immediately without a separate drying step or after only slight drying, thereby reducing the energy required for the process.

[0049] In addition, the manufacturing method of the present 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 performed using methods known in the art (e.g., US 2021-0094903 A1) without limitation. Furthermore, specific conditions may be appropriately modified to optimize the process, but are not limited thereto.

[0051] The present application provides L-valine crystals comprising polyvinyl alcohol and L-valine according to the present application, wherein the amount of moisture in the separated crystals is reduced by 5 to 40% compared to L-valine crystals prepared without using polyvinyl alcohol during concentration.

[0052] For example, the above L-valine crystals may have a spherical particle shape.

[0053] Specifically, the L-valine crystals of the present application may be produced by the method described above. Furthermore, the L-valine crystals of the present application may be used as feed or feed additives, but their use is not limited thereto.

[0055] A method for manufacturing valine granules comprises the steps of: preparing a fermentation liquid containing valine; adjusting the pH of the fermentation liquid; adding polyvinyl alcohol to the fermentation liquid; separating valine crystals containing water from the fermentation liquid; mixing the valine crystals with a seed to produce mixed granules; and drying the valine mixed granules.

[0056] Here, the steps of preparing the fermentation liquid, adjusting the pH of the fermentation liquid, adding polyvinyl alcohol to the fermentation liquid, and separating valine crystals can be performed in the same way as in the previously described method for manufacturing valine crystals. Therefore, to avoid duplication of explanation, the following description will focus on the steps of mixing valine crystals with seeds to produce mixed granules; and drying the mixed granules.

[0058] The valine crystals obtained in the valine crystal separation step of the mixed granule manufacturing step are mixed with seeds for the manufacture of valine granules.

[0059] The seed used in the mixed granule manufacturing step is also called a seed crystal or seed crystal, and may refer to a substance used as a catalyst for the crystallization or granulation of a liquid. The seed in this application may be a valine crystal. When the seed comes into contact with the fermentation liquid, the solid components present in the fermentation liquid combine with the seed and aggregate to form granules.

[0060] The seeds used in the mixed granule manufacturing step may have an average particle size of 150 to 300 μm. Specifically, seeds having 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. Since the particle size of the seeds used may consequently affect the productivity of manufacturing the granules according to the present application, a person skilled in the art may appropriately select it by considering the desired moisture content, etc.

[0061] A mixing granulator may be used in the mixed granule manufacturing step. The mixing granulator may obtain granules by injecting seeds into the mixing granulator at a constant rate through a feeder while simultaneously supplying valine crystals obtained in the preceding separation step. The mixing granulator may each include a feeder for supplying seeds internally and a component for supplying valine crystals. Additionally, the mixing granulator may be provided with a gas nozzle for generating air flow inside the chamber, a paddle for mixing the seeds and valine crystals provided inside the chamber, etc. As the seeds and valine crystals introduced into the chamber clump together, valine mixed granules may be formed.

[0063] According to one embodiment of the present application, valine mixed granules with low moisture content and large crystal size can be produced by mixing seeds and valine crystals containing moisture. As previously discussed, according to the present application, valine crystals with large crystal size are precipitated, and since valine crystals with large crystal size can be easily separated from the fermentation liquid, the moisture content within the valine crystals is relatively low. Furthermore, as the valine crystals with low moisture content and seeds are granulated in a mixing-type granulator during the mixed granule manufacturing step, the valine mixed granules produced also have low moisture content and large size.

[0064] Here, "granules" are macroscopic particles that are larger permanent aggregates formed by the aggregation of small particles such as powder, and may be particles with an average particle diameter of 50 μm to 5 mm, 75 μm to 4 mm, or 100 μm to 3 mm.

[0065] The valine mixed granules obtained in the mixed granule manufacturing step 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 low moisture content compared to valine granules obtained according to the prior art. Therefore, the amount of energy required to dry the valine mixed granules obtained according to the present application can be reduced.

[0066] Next, a drying step is performed to dry the valine mixed granules.

[0067] In the drying step, the previously obtained valine mixed granules are dried, and there are no restrictions on the drying method.

[0068] In one aspect of the present application, the present application may provide a valine product comprising valine mixed granules. The term "valine product" in the present application refers to a product made by commercializing valine contained in a fermented liquid into various formulations. For example, a valine product may refer to a valine-containing mixture in the form of granules. However, if necessary, the formulation of the valine product may be different without altering the inventive concept of the present application. Furthermore, subsequent processes may be performed to realize various formulations of the valine product as described above. The valine product described above may be used as an additive to animal feed, and there are no limitations on its use.

[0069] According to the present application, valine crystals can be separated by concentrating a fermentation liquid containing valine, and valine mixed granules with large size and low moisture content can be produced by mixing the separated valine crystals with seeds. The valine mixed granules with low moisture content have the advantage of requiring less energy for drying. For example, according to the present application, the moisture content in the valine mixed granules can be further reduced by adjusting the pH of the fermentation liquid or controlling the concentration rate.

[0071] The L-valine crystals or granules of the present application may be suitable for use in the manufacture of animal feed as feed additives. For example, as a feed additive, the L-valine crystals may be mixed with the feed material itself as part of an animal feed premix or as a precursor of animal feed. A 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. Additionally, the feed composition may be easily administered to animals as a top dressing, by mixing them directly into animal feed, or as an oral formulation separate from the feed. Effects of the invention

[0073] According to the present application, the energy required for drying can be reduced by lowering the moisture content in valine crystals or valine mixed granules through pH adjustment of a fermentation liquid containing valine and the addition of PVA. Brief explanation of the drawing

[0075] Figure 1 is a figure showing SEM images of valine crystals prepared according to one embodiment of the present invention. (a) and (b) respectively show valine crystals prepared by adding no PVA or 2 wt% to the culture medium. Specific details for implementing the invention

[0076] The present application is to be described in more detail below through the following examples. However, the following examples are intended only to illustrate the present application and do not limit the scope of the present application to these examples alone. Meanwhile, each description and embodiment disclosed in the present application may be applied to other descriptions and embodiments. That is, all combinations of the various elements disclosed in the present application fall within the scope of the present application. Furthermore, numerous papers and patent documents are referenced and cited throughout this specification. The disclosures of the cited papers and patent documents are incorporated by reference into this specification in their entirety to more clearly explain the state of the art to which the present invention pertains and the content of the present invention.

[0078] Experimental Example 1: Preparation of valine fermentation liquid through Corynebacterium microbial culture

[0080] In order to prepare granules containing L-valine in this experimental example, Corynebacterium glutamicum KCCM11338P, which produces L-valine, was cultured for 72 hours at approximately 30°C in a medium composed of 5% glucose, 2% ammonium sulfate, 0.1% potassium dihydrogen phosphate, 0.05% magnesium sulfate heptahydrate, 2.0% CSL (corn steeping liquid), 200 μg / L biotin, and pH 7.2 to obtain a fermentation liquid having the following composition. The fermentation liquid contained the cultured medium and microorganisms, from which moisture content was measured and composition analyzed. Table 1 shows the results of the analysis of the valine fermentation liquid composition.

[0082] furtherance Content (g / L) Valin 80.0 Other amino acids 8.8 organic acids 0.7 minerals 11.0 moisture(%) 89.0

[0084] Experimental Example 2: Comparison of moisture content in valine crystals according to pH of fermentation liquid

[0086] The fermentation liquid prepared in Experimental Example 1, having an L-valine concentration of 80 g / L, was divided into 2 L portions, and sulfuric acid was added to prepare process liquids at different pH levels (7.5 to 3.0). To precipitate valine crystals from the prepared process liquids, a vacuum concentrator was used to concentrate the liquids at a rate of 60 g / L / hr at a vacuum of 120 torr until the valine concentration reached 200 g / L. The concentrated crystal slurry containing valine crystals was separated into solid and liquid using a basket separator to obtain L-valine crystals and the mother liquor.

[0087] The moisture content in valine crystals according to the pH of the fermentation liquid was compared through LOD analysis (Table 3).

[0089] pH of the fermentation liquid 7.0 6.0 5.0 4.0 3.0 Slurry viscosity (cP) 89 80 20.5 16.0 90 Moisture content (wt%) in crystals 45 40 32 30 39

[0091] LOD moisture measurement results confirmed that the moisture content in the valine crystals was lowest when the pH of the fermentation liquid was greater than 3.0 and less than 6.0. In addition, when analyzing the viscosity of the concentrated slurry, it was confirmed that the viscosity of the concentrated slurry was significantly lower when the pH of the fermentation liquid was greater than 3.0 and less than 6.0. Low viscosity of the concentrated slurry means that the size of the valine crystals contained in the concentrated slurry is large and that few fine crystals are formed. In contrast, for the fermentation liquids with pH 7.0, pH 6.0, and pH 3.0, which showed high viscosity of the concentrated slurry, it is analyzed that the high viscosity is due to the formation of many valine fine crystals.

[0092] 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 are formed within a specific pH range, resulting in low viscosity of the concentrated slurry and low moisture content in the separated crystals.

[0094] Experimental Example 3: Comparison of moisture content in valine crystals according to the type of additive

[0096] To confirm the effects of the presence and / or type of additives during the process of preparing valine crystals from a valine-containing culture medium, a culture medium was prepared by adding 2 wt% (based on the weight of L-valine) of polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), and monosodium glutamate (MSG) to an L-valine culture medium prepared in Experimental Example 1, which had been adjusted to pH 3.8 by adding sulfuric acid. These culture mediums were concentrated to a concentration of 200 g / L at a vacuum level of 120 torr and a rate of 30 g / L / hr using a vacuum concentrator. Subsequently, solid and liquid were separated using a basket separator at 1800 rpm for 10 minutes to obtain L-valine crystals from the obtained concentrated culture medium, and the moisture content of the separated L-valine crystals was calculated and compared using LOD analysis (Table 3).

[0098] additives Moisture content (wt%) in valine crystals No additives (control group) 58.21 PVA 40.12 PVP 57.89 MSG 59.34

[0100] As shown in Table 3 above, while there was no significant change in the moisture content within the crystals when other additives were used, it was confirmed that the crystals obtained from the process using PVA showed a moisture content within the crystals reduced by more than 30% compared to the control group without additives. This indicates that adding PVA to the culture medium prior to concentration is effective in lowering the amount of moisture contained in the final obtained valine crystals.

[0102] Experimental Example 4: Comparison of moisture content in valine crystals according to the amount of PVA used

[0104] Using PVA, which showed the best effect in Experimental Example 3 above, the effect according to the amount of additive used was confirmed while varying the input amount. Specifically, culture solutions prepared with different input amounts of 0.5, 1.5, 2.0, and 2.5 wt% (based on the weight of L-valine) were concentrated and separated as in Experimental Example 3 above to obtain crystals, and the moisture content of the separated L-valine crystals was calculated by LOD analysis (Table 4).

[0106] PVA Addition Amount (wt%) 0 0.5 1.5 2.0 2.5 Moisture content (wt%) in crystals 58.21 53.07 47.23 38.02 48.23

[0108] Samples within the entire range of tested PVA input amounts showed reduced crystal moisture content compared to the control sample without input (0 wt%), and a reduction rate of 34.7% from approximately 9.1% was observed.

[0110] Furthermore, the morphology of the crystals generated from the 2wt% PVA sample and the control group without input was observed using SEM (×30x magnification, JEOL, JCM-6000PLUS). As a result, the control group without PVA input produced plate-shaped fine crystals, whereas the 2wt% PVA input group formed larger particles that were close to spherical (Fig. 1).

[0112] Experimental Example 5. Preparation of valine granules from isolated crystals

[0114] Valine crystals were prepared in the same manner as in Experimental Example 4, and separated valine crystals and pre-dried valine seeds (valine content 75%) were mixed to produce crystals with a moisture content of 15% to 47%, and then valine mixed granule crystals were prepared using a mixing granulator.

[0115] It was confirmed that mixed granules can be manufactured using a mixing granulator for all crystals with a moisture content of 15% to 47%.

[0116] Mixed moisture (%) 15.0 24.0 30.0 35.0 47.0 facility Type CVG Mixer rpm 2000 Presence or absence of mixed granules ○ ○ ○ ○ ○

[0118] From the foregoing description, those skilled in the art to which this application pertains will understand that this application may be implemented in other specific forms without altering its technical concept or essential features. In this regard, the embodiments described above should be understood as illustrative in all respects and not restrictive. The scope of this application should be interpreted as including all modifications or variations derived from the meaning and scope of the claims set forth below and their equivalents, rather than from the detailed description above.

Claims

Claim 1 A method for producing valine crystals, comprising the steps of: preparing a fermentation liquid containing valine; adjusting the pH of the fermentation liquid to greater than 3 and less than 6; adding polyvinyl alcohol (PVA) to the fermentation liquid and then concentrating it; and separating valine crystals containing water from the fermentation liquid. Claim 2 delete Claim 3 A method for producing valine crystals according to claim 1, wherein the polyvinyl alcohol is added in an amount of 0.1 wt% to 5 wt% based on the total weight of the fermentation liquid. Claim 4 delete Claim 5 A method for producing valine crystals according to claim 1, wherein the concentration is performed by removing moisture from the fermentation liquid at a rate of 30 g / L / hr to 150 g / L / hr. Claim 6 A method for manufacturing valine crystals according to claim 1, wherein the valine crystal has a viscosity greater than 0 and less than 80 cP. Claim 7 A method for manufacturing valine crystals according to claim 6, wherein the valine crystals contain 10 wt% to 55 wt% of moisture. Claim 8 A method for manufacturing valine crystals according to claim 1, wherein the valine crystals have a spherical particle shape. Claim 9 A method for manufacturing valine granules, comprising the steps of: preparing a fermentation liquid containing valine; adjusting the pH of the fermentation liquid to greater than 3 and less than 6; adding polyvinyl alcohol to the fermentation liquid and then concentrating it; separating valine crystals containing water from the fermentation liquid; mixing the valine crystals with a seed to produce mixed granules; and drying the valine mixed granules. Claim 10 delete

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