Slow-release fertilizer containing glutathione

Abstract

To provide a fertilizer capable of sustainably exerting a function of oxidized type glutathione when using the oxidized type glutathione as fertilizer.SOLUTION: The present invention has been completed by finding out that glutathione is slowly eluted by solidifying a composition including glutathione and yeast such as the glutathione and glutathione-containing yeast extract with Na-type or Ca-type bentonite as carrier.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a solidified fertilizer composition containing glutathione and bentonite.

Background Art

[0002] Glutathione (γ-glutamyl-L-cysteinylglycine) is a tripeptide composed of L-cysteine, L-glutamic acid, and glycine. Reduced glutathione and oxidized glutathione, which is formed when the thiol groups on the L-cysteine residues of two molecules of reduced glutathione are oxidized to form a disulfide bond between the two glutathione molecules, are known in the art.

[0003] Glutathione exists not only in humans but also widely in animals, plants, microorganisms, etc., and is known to have effects such as detoxification, antioxidant activity, and imparting richness of flavor. Glutathione is not only used in the fields of pharmaceuticals, cosmetics, etc., but also widely used for animals and plants in applications such as feed and plant growth agents.

[0004] Various methods have been studied to more effectively exert the functions of glutathione that has such various uses. Patent Document 1 discloses a method of adding cyclodextrin, Patent Document 2 discloses a method of adding arginine, and Patent Document 3 discloses a method of stabilizing glutathione with an alkaline mineral carrier and Na-type bentonite.

[0005] It is also known that when oxidized glutathione is used as a fertilizer, the harvest index is improved. On the other hand, when oxidized glutathione is applied to soil, there was a possibility that glutathione would rapidly elute into the soil with water. Therefore, when applying glutathione to plants, a configuration that allows glutathione to be absorbed by plants in a steady manner is required.

Prior Art Literature

Patent Literature

[0006]

Patent Document 1

[0007] The objective of this invention is to find a way to more effectively exert the functions of glutathione. [Means for solving the problem]

[0008] The inventors, through diligent research to solve the above problems, have discovered that by solidifying a composition containing glutathione and yeast cells, such as glutathione or glutathione-containing yeast extract, using a Na-type or Ca-type bentonite carrier, the elution of glutathione can be slowed down, thus completing the present invention.

[0009] The present invention is as follows: (1) Fertilizer containing glutathione, yeast cells, and bentonite, (2) The fertilizer in (1) above, wherein the glutathione is an oxidized glutathione-containing yeast extract. (3) The yeast cells are the yeast cells after yeast extract extraction, as described in (1) or (2) above. (4) The fertilizers described in (1) to (3) above, wherein the bentonite is Na-type bentonite. (5) The fertilizers of (1) to (4) above, wherein the bentonite is a mixture of Na-type bentonite and Ca-type bentonite. [Effects of the Invention]

[0010] According to the present invention, the function of glutathione can be maintained for a long period of time, and therefore, a composition and method can be provided that imparts the sustained release property of glutathione when used as a fertilizer. In this invention, sustained release means that the active ingredient, glutathione, is released slowly from the granules. [Modes for carrying out the invention]

[0011] Reduced glutathione is a tripeptide having the structure γ-L-Glu-L-Cys-Gly, while oxidized glutathione is formed by two molecules of reduced glutathione linked by disulfide bonds. Hereinafter, reduced glutathione may be abbreviated as GSH, and oxidized glutathione as GSSG. Furthermore, the term "glutathione" in this application refers to glutathione including both oxidized and reduced forms.

[0012] The glutathione used in this invention may be in any form, such as purified glutathione, crystalline glutathione, glutathione unbound to other substances, or a salt formed with an acid or base. Furthermore, it may be glutathione contained in yeast or yeast extract, or in a mixture of reduced and oxidized forms, reduced form only, or oxidized form only. Yeast extract is an extract obtained by culturing yeast, collecting the yeast cells, washing them, and then extracting them by hot water extraction, enzymatic extraction, acid or alkaline extraction, or a combination thereof. The yeast used may contain glutathione (regardless of whether it is oxidized or reduced). Industrially usable yeast is preferred, and specific examples include baker's yeast, brewer's yeast, and Torula yeast. When using glutathione in yeast or yeast extract, commercially available products may be used. For example, yeast containing a large amount of glutathione includes "Hythion Corpo MG" (Mitsubishi Corporation Life Sciences Co., Ltd.), and yeast extracts containing glutathione include "Hythion Extract YH-D12", "Hythion Extract YH-D18", "Hythion Extract YH-D20", and "Hythion Extract YH" (Mitsubishi Corporation Life Sciences Co., Ltd.).

[0013] Furthermore, glutathione can be produced using known methods. An example of glutathione-containing yeast extract production is described below. By extracting yeast extract from glutathione-containing yeast cells, a yeast extract containing 15% by mass or more of glutathione can be obtained. There are no particular restrictions on the yeast culture method, but generally either batch culture or continuous culture is used. Commonly used culture media can also be used. For example, glucose, acetic acid, ethanol, glycerol, molasses, sulfite pulp wastewater, wood-derived cellulose decomposition products, etc. can be used as carbon sources, and urea, ammonia, ammonium sulfate, ammonium chloride, nitrates, etc. can be used as nitrogen sources. For example, superphosphate, potassium, and magnesium can be used, such as superphosphate, ammonium phosphate, potassium chloride, potassium hydroxide, magnesium sulfate, magnesium chloride, etc., and inorganic salts such as zinc ions, copper ions, manganese ions, and iron ions may also be added. In addition, vitamins, amino acids, nucleic acid-related substances, etc., or organic substances such as casein, yeast extract, meat extract, and peptone may be added. The culture temperature is 21-37°C, preferably 25-34°C, and the pH is 3.0-8.0, particularly preferably 3.5-7.0.

[0014] The yeast extract of the present invention is extracted after culturing the yeast cells. There are no particular restrictions on the method of extracting the yeast extract, but it can generally be done by autolysis, hot water extraction, enzyme extraction, acid or alkali extraction, or a combination thereof.

[0015] To extract yeast extract by autolysis, for example, stir the yeast culture solution at 55°C for 4 hours. For enzyme extraction, add cell wall lysis enzymes or proteases to the yeast culture solution and allow the reaction to proceed. For acid extraction, adjust the yeast culture solution to an acidic state with sulfuric acid before extraction. For alkaline extraction, adjust the yeast culture solution to an alkaline state before extraction. Alternatively, a combination of methods, such as performing enzyme extraction after autolysis, is also possible.

[0016] After yeast extract extraction, the yeast residue is separated by centrifugation or other means, and after concentration, a glutathione-containing yeast extract can be obtained by freeze-drying or hot-air drying.

[0017] Incidentally, glutathione in the yeast extract extracted as described above may contain a large amount of reduced glutathione. In this case, oxidized glutathione can be obtained by subjecting reduced glutathione to an oxidation treatment to convert it into oxidized glutathione. The oxidation treatment method may be any known treatment method and can be arbitrarily selected; for example, the oxidation treatment can be performed by aeration or the like. A yeast extract containing oxidized glutathione can also be produced by the method described in Japanese Unexamined Patent Application Publication No. 2004-283125.

[0018] The glutathione content in the composition of the present invention can be adjusted as desired. When the composition is used for plant applications, the glutathione content is generally adjusted to 1% by weight or more. Regarding the proportion of bentonite, yeast cells and glutathione, it is preferable that bentonite and yeast cells account for 70% by weight or more of the composition. More preferably, the proportion is 80% by weight or more, and still more preferably 90% by weight or more.

[0019] Examples of bentonite include sodium bentonite, calcium bentonite, activated bentonite and the like. In the present invention, calcium bentonite and sodium bentonite are used. Calcium bentonite refers to bentonite in which the interlayer cations of montmorillonite in the bentonite are mainly calcium ions. The montmorillonite content is preferably 45% or more, and more preferably 55% or more. In addition, the cation exchange capacity, which is one of the quality indicators specified in the standard test method of the Japan Bentonite Manufacturers Association, is 40 meq / 100g or more, more preferably 60 meq / 100g or more. In the present invention, sodium bentonite refers to bentonite having a Ca / Na concentration ratio (molar ratio) among leached ions of 0.9 or less, preferably 0.8 or less, in accordance with the analysis standards of the Japan Bentonite Manufacturers Association.

[0020] In the present invention, sodium-type bentonite may be used alone, or calcium-type bentonite (Ca-type) may be mixed with sodium-type bentonite (Na-type). When mixing, the ratio of Ca-type:Na-type is preferably 20:80 to 80:20, more preferably 30:70 to 70:30, and particularly preferably equivalent mixing of Ca-type and Na-type is preferred.

[0021] In the present invention, yeast cells are further mixed. It is preferable to use the solid component obtained after extracting yeast extract and the like from yeast as the yeast cells (hereinafter referred to as yeast cells). There is no particular limitation on the method for extracting yeast extract from yeast cells, and it is generally carried out by autolysis, hot water extraction, enzymatic extraction, acid or alkali extraction, or a combination thereof. It is particularly preferable to use the yeast cells or solid content after extraction by these extraction methods. In the present invention, those obtained by drying said yeast cells or solid content by a known method such as drum drying or spray drying are used.

[0022] In the present invention, when glutathione and bentonite are caused to contain yeast cells, the mixing ratio of glutathione, bentonite and yeast cells can be appropriately adjusted according to the application. Usually, components other than bentonite and yeast cells, such as glutathione and glutathione-containing compositions such as yeast extract, are not limited as long as they can be solidified using bentonite and yeast cells as carriers. There is also no particular limitation on the mixing ratio of bentonite and yeast cells, and it may be appropriately adjusted, for example, to bentonite:yeast cells = 20:80 to 80:20.

[0023] Furthermore, the present invention may also include carriers other than bentonite and yeast cells. The carrier used can be appropriately selected according to the intended use, and there are no restrictions. The amount of carrier used should also be less than the amount of bentonite. Examples of carriers that can be used include inorganic materials such as talc, clay, vermiculite, diatomaceous earth, kaolin, calcium carbonate, calcium hydroxide, white clay, and silica gel; excipients used in food manufacturing such as wheat flour, starch, and dextrin; microbial carriers such as Aspergillus oryzae and filamentous fungi; and thickeners such as gelatin, β-glucan, xanthan gum, and arabic gum; and organic materials such as grain flour and soy flour.

[0024] Furthermore, depending on the intended use, in addition to the mixtures mentioned above, if used as a fertilizer, components such as potassium, nitrogen, phosphorus, calcium, and magnesium can be added as fertilizer components. In addition, anionic surfactants such as alkyl sulfates, alkyl sulfons, alkylaryl sulfons, and dialkyl sulfosuccinates; cationic surfactants such as salts of higher aliphatic amines; nonionic surfactants such as polyoxyethylene glycol alkyl ethers, polyoxyethylene glycol acyl esters, polyoxyethylene glycol polyhydric alcohol acyl esters, and cellulose derivatives; thickeners, fillers, and binders such as gelatin, casein, and gum arabic; and fertilizer components such as benzoic acid, nicotinic acid, nicotinamide, and pipecolic acid can be added without restriction. These mixtures may be adjusted as appropriate in accordance with general restrictions on their use. For example, when used as fertilizer, they can be adjusted as appropriate in accordance with the requirements for fertilizer registration.

[0025] The method for producing the composition of the present invention is not particularly limited. When the materials used are particles such as powders or granules, a preferred method includes a mixing step of forming a mixture of glutathione or a glutathione-containing composition, yeast cells, and bentonite with water or a water-soluble solvent, and a granulation step of forming particles from the mixture. In the mixing step, other components other than glutathione or a glutathione-containing composition, yeast cells, and bentonite mentioned above may be mixed as needed. In the mixing step, it is preferable to thoroughly disperse the glutathione or a glutathione-containing composition, yeast cells, and bentonite dissolved in the solvent with the other mixed components. The amount of solvent used in the mixing step is not particularly limited, and an appropriate amount of solvent should be used to obtain a sufficiently homogeneous mixture. The solvent can be water, alcohols such as ethanol, or a mixed solvent of water and alcohols.

[0026] The mixture produced in the mixing step is granular, paste-like, or liquid, and is then solidified in a granulation step. The granulation step can be carried out by conventional granulation methods such as extrusion granulation, agitation granulation, rolling granulation, or compression granulation. The granulation step may include a sizing step or a drying step as needed. In the drying step, the solvent is removed by evaporation.

[0027] The present invention includes a method for cultivating plants by applying the above composition to the plants. There are no restrictions on the plants to which the present invention can be applied; it is not particularly limited to the plants to which the present invention can be applied, and can be applied to a wide range of plants, including various monocots, dicots, trees, and other plants.

[0028] The method for measuring the oxidized glutathione concentration of the present invention was performed using the DTNB-HPLC method (Journal of Chromatography, 194 (1980) pp. 424-428). The oxidized glutathione content in this invention is calculated by subtracting the reduced glutathione content from the total glutathione content, which is measured after all glutathione has been reduced using dithiothreitol. [Examples]

[0029] The present invention will be described in more detail below, but it is not limited to the following specific examples. [Examples]

[0030] (Manufacturing of granular formulations) A granular preparation was manufactured using glutathione or oxidized glutathione-containing yeast extract and bentonite. The glutathione and oxidized glutathione-containing yeast extract used was that sold by Mitsubishi Corporation Life Sciences Co., Ltd. (YH-D20). The yeast cells used were KR yeast (sold by Mitsubishi Corporation Life Sciences Co., Ltd.).

[0031] [Table 1]

[0032] The granular material was prepared by combining the ingredients listed in Table 1, adding an appropriate amount of water while stirring, and then kneading. The mixture was extruded through a 1.2 mm wide plate and dried at 75°C for 24 hours under atmospheric pressure. After drying, it was crushed, and fine powder and coarse particles were removed using a sieve.

[0033] The sustained-release properties were evaluated by measuring the amount of oxidized glutathione eluted using the following method. 5g of each granular preparation prepared in the previous step was placed in a 200ml capacity glass filter. 50ml of water was poured into the filter, and the amount of oxidized glutathione in the eluate was measured after 24 hours. The amount of oxidized glutathione was measured according to the method described in this specification. The measurement results are shown in Table 2.

[0034] [Table 2]

Claims

1. A sustained-release fertilizer that slows down the elution of oxidized glutathione, comprising oxidized glutathione-containing yeast extract, yeast cells after yeast extract extraction, and Na-type bentonite.

2. A sustained-release fertilizer that slows the elution of oxidized glutathione according to claim 1, wherein the bentonite is a mixture of Na-type bentonite and Ca-type bentonite, further containing Ca-type bentonite.

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