Method for preparing water-soluble chelated calcium from bean dreg degradation liquid

Abstract

The invention relates to the technical field of fertilizers, in particular to a method for preparing water-soluble chelated calcium from a bean dreg degradation liquid, which comprises the following steps: adding poly bean dregs into a fermentation tank, adjusting the fermentation temperature to 30-50 DEG C, adjusting the pH value to 7-9, keeping for 18-30 hours, killing fermentation microorganisms, degrading protein in the poly bean dregs into polypeptide amino acid, and adding the treated poly bean dregs into a fermentation tank for fermentation, so as to obtain the water-soluble chelated calcium. In the initial stage (1-3 h) of the hydrolysis reaction, the hydrolysis degrees of different proteins are slightly different, the difference is gradually obvious along with the time, the final hydrolysis degrees are greatly different, the alcohol washing + X enzyme accounts for 7.67%, the heating + X enzyme accounts for 7.56%, the alcohol washing + H enzyme accounts for 7.25% and the X enzyme accounts for 7.14%, calcium ions are chelated, and the calcium ions cannot be directly absorbed by plants and need to be gradually degraded into amino acids in soil and then absorbed by the plants, so that the calcium ions are not directly absorbed by the plants. In the non-degradation process, insoluble calcium ions in the soil can be continuously replaced out for plant absorption, and the effect is longer, so that the absorption efficiency of the calcium fertilizer is improved, and the fertilizer efficiency of the calcium fertilizer is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of fertilizer production, and specifically to a method for preparing water-soluble chelated calcium from a fermented waste bean dregs solution. Background Art

[0002] The inorganic plant nutrition theory proposed by the modern agricultural chemist Liebig holds that to maintain soil fertility, the inorganic nutrients and nitrogen taken up and removed from the farmland by plants must be returned to the soil in the form of fertilizers. According to relevant records, the import of chemical fertilizers in China began in 1905. In the 1930s, national fertilizer efficiency tests, known as soil fertility determination, were organized. The test results showed that nitrogen was extremely lacking, and phosphorus was only lacking in the Yangtze River Basin or provinces south of the Yangtze River. Systematic investigations and determinations of the soil types, characteristics, and fertility status in China promoted the application of chemical fertilizers and agricultural chemistry research. In 1949, the annual output of nitrogen fertilizer in China was only 0.6 million tons. In 1990, the domestic chemical fertilizer output reached 18.797 million tons, ranking third in the world. In 1998, the chemical fertilizer output reached 29.56 million tons, accounting for 19% of the world's total output, ranking first in the world. Chemical fertilizers have become an important agricultural material in China and play a significant role in agricultural production. Potassium is abundant in the soil. Among the nutrients required for plant growth, calcium ranks fourth after nitrogen, phosphorus, and potassium. Specifically for solanaceous and cruciferous crops, the demand for calcium is even greater. If calcium is lacking, plant growth will be inhibited, and phenomena such as heartburn, fruit cracking, deformed fruits, and root aging will occur, affecting crop yield and quality.

[0003] In the prior art, such as: CN105565910A, a method for preparing a bioactive polypeptide calcium fertilizer. In the method for preparing the bioactive polypeptide calcium fertilizer of the present invention, calcium oxide is used as the calcium source. In an aqueous solution system, calcium oxide reacts with water and releases heat, which helps to accelerate the reaction rate and solves the problem that calcium hydroxide is easily converted into calcium carbonate precipitation by carbon dioxide in the air. Manganese ions are introduced into the polypeptide calcium fertilizer. Calcium and manganese ions are chelated by peptide bonds and carboxyl groups on the main chain to form stable five-membered rings, endowing the polypeptide calcium with biological activity. While supplementing calcium to plants, its biological activity will greatly delay the senescence of plants and achieve a significant yield increase effect.

[0004] However, there are still certain deficiencies in the use of this method. Among them, trace elements mostly exist as divalent metal ions. When directly entering the soil through fertilizers, due to the large amounts of divalent carbonate ions and trivalent phosphate ions in fertilizers and the soil, they are extremely likely to react with them to form water-insoluble carbonates and phosphates. Most of them will lose their activity, and only a small amount can be absorbed by plants, resulting in certain limitations in utilization efficiency. Although the solubility is very good, after being applied to the soil, the part that is not absorbed by plants is combined with anions such as sulfate ions, phosphate ions, and carbonate ions in the soil, becoming insoluble calcium fertilizers, causing great waste. Therefore, how to improve the absorption efficiency of calcium fertilizers and extend the fertilizer efficiency of calcium fertilizers has become a problem that needs to be solved by those skilled in the art. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for preparing water-soluble chelated calcium from soybean residue degradation liquid to solve the problems mentioned in the above background technology: there are large amounts of divalent carbonate ions and trivalent phosphate ions in fertilizers and the soil, which are extremely likely to react with them to form water-insoluble carbonates and phosphates. Most of them will lose their activity, and only a small amount can be absorbed by plants, resulting in certain limitations in utilization efficiency. Although the solubility is very good, after being applied to the soil, the part that is not absorbed by plants is combined with anions such as sulfate ions, phosphate ions, and carbonate ions in the soil, becoming insoluble calcium fertilizers, causing great waste. Therefore, how to improve the absorption efficiency of calcium fertilizers and extend the fertilizer efficiency of calcium fertilizers has become a problem that needs to be solved by those skilled in the art.

[0006] To achieve the above purpose, the present invention provides the following technical solutions:

[0007] A method for preparing water-soluble chelated calcium from soybean residue degradation liquid, comprising the following steps:

[0008] Step 1: Add poly-soybean residue to a fermentation tank, adjust the fermentation temperature to 30 - 50 °C, and the pH value to 7 - 9, and maintain for 18 - 30 hours to kill fermentation microorganisms and degrade the protein in the poly-soybean residue into polypeptide amino acids;

[0009] Step 2: For the treated poly-soybean residue, in the initial stage (1 - 3 h) of the hydrolysis reaction, the hydrolysis degrees of different proteins vary little. As time extends, the differences become gradually obvious, and there are significant differences in the final hydrolysis degrees. The hydrolysis degree of alcohol washing + X enzyme is 7.67%, that of heating + X enzyme is 7.56%, that of alcohol washing + H enzyme is 7.25%, and that of X enzyme is 7.14%;

[0010] Step 3: The substrate concentration (proportion in water) is 5%, 10%, 15%, 20%, 25%. Taking the hydrolysis degree as the index for investigation, determine the optimal substrate concentration. As the enzyme addition amount increases, the hydrolysis degree of soybean residue shows an upward trend. Select enzyme addition amounts of 150 U / g, 300 U / g, and 450 U / g for response surface experimental analysis of the subsequent experimental results;

[0011] Step 4: The degree of hydrolysis of soybean dregs is relatively high. To obtain polypeptides with a high degree of hydrolysis and determine the optimal process parameters for hydrolyzing soybean dregs with alkaline protease X, based on single-factor experiments, with five factors including hydrolysis temperature, time, pH value, enzyme concentration, and substrate concentration as independent variables, and the degree of hydrolysis of soybean dregs as the response value, a quadratic regression equation with five factors and three levels was designed to fit the functional relationship between the factors and the index. Response surface analysis was used to seek the optimal process parameters for enzymatic hydrolysis.

[0012] As a preferred embodiment of the present invention, when the substrate concentration is too high, the soybean dregs become semi-solid, resulting in uneven hydrolysis. With substrate concentrations of 5%, 10%, 15%, 20%, and 25%, response surface experiments were conducted to determine the optimal substrate concentration.

[0013] As a preferred embodiment of the present invention, when the pH reaches 8, the degree of hydrolysis of soybean dregs protein reaches the maximum because the enzyme has the greatest activity under the optimal reaction pH conditions. Being greater than or less than the optimal pH will affect its activity. Therefore, pH values of 7, 8, and 9 were selected for response surface experiments.

[0014] As a preferred embodiment of the present invention, the degree of hydrolysis of soybean dregs reaches the maximum at 5 h. Without fermentation, at a hydrolysis time of 24 h, the enzymatic hydrolysis reaction tends to be complete.

[0015] As a preferred embodiment of the present invention, with the increase in the enzymatic hydrolysis temperature, the degree of hydrolysis shows a trend of first increasing and then decreasing. When the temperature reaches 50 °C, the degree of hydrolysis of both proteins reaches the maximum.

[0016] As a preferred embodiment of the present invention, as the degree of hydrolysis increases, the degree of hydrolysis decreases after 50 °C. Hydrolysis response surface experiments were conducted at 40, 50, and 60 °C.

[0017] As a preferred embodiment of the present invention, with the reduction of the enzymatic hydrolysis substrate and the decrease in concentration, the large accumulation of products has a competitive inhibition on the enzymatic hydrolysis reaction. Hydrolysis response surface experiments were conducted at 18, 24, and 30.

[0018] As a preferred embodiment of the present invention, the ethanol aqueous solution has a denaturing effect on soybean protein, changing the compact spherical shape of soybean protein into a loose structure, and the degree of hydrolysis of alcohol washing + enzyme X is the highest.

[0019] As a preferred embodiment of the present invention, the results were processed using Design-Expert software, and the regression equation is as follows:

[0020] DH = +7.07 + 0.44*A + 0.22*B + 0.41*C + 0.31*D - 0.68*E + 0.59*AB + 0.80*AC - 0.16*AD + 0.60*AE + 0.67*BC + 0.37*BD - 0.12*BE + 0.05*CD - 0.32*CE - 0.34*DE - 0.16*A^2 - 0.54*B^2 - 0.51*C^2 - 0.35*D^2 - 0.11*E^2h。

[0021] As a preferred embodiment of the present invention, the application of the polypeptide amino acid chelated micro-fertilizer in crop fertilization.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] 1. In the present invention, by chelating calcium ions, the calcium ions are protected from side reactions with other substances, so that around the crop roots, nutrients required by plants are continuously provided. After the polypeptide amino acid chelated calcium fertilizer is applied to the soil, the polypeptide amino acid, as a macromolecule, cannot be directly absorbed by plants and needs to be gradually degraded into amino acids in the soil before being absorbed by plants. During the process of not being degraded, it can continuously displace the insoluble calcium ions in the soil for plant absorption, which is more long-lasting, thereby improving the absorption efficiency of calcium fertilizer and prolonging the fertilizer efficiency of calcium fertilizer.

[0024] 2. In the present invention, the ethanol aqueous solution has a denaturing effect on soy protein, changing the compact spherical shape of soy protein into a loose structure. The hydrolysis degree of alcohol washing + X enzyme is the highest, which is consistent with the result reported that alcohol-denatured soy protein is easily acted on by protease. Therefore, treating soybean dregs with alcohol is beneficial to the enzymatic hydrolysis of proteins. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic structural diagram of the hydrolysis degree progress curve of different treatments of the present invention;

[0026] Figure 2 It is a schematic structural diagram of the influence of substrate concentration on hydrolysis degree of the present invention;

[0027] Figure 3 It is a schematic structural diagram of the influence of pH on hydrolysis degree of the present invention;

[0028] Figure 4 It is a schematic structural diagram of the influence of enzyme dosage on hydrolysis degree of the present invention;

[0029] Figure 5 It is a schematic structural diagram of the influence of time on hydrolysis degree of the present invention;

[0030] Figure 6 It is a schematic structural diagram of the influence of temperature on hydrolysis degree of the present invention;

[0031] Figure 7 This is the structural schematic diagram of the response surface variance analysis of the present invention. Detailed implementation manners

[0032] Next, in combination with the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0033] For the embodiment, please refer to Figure 1-7 The present invention provides a technical solution:

[0034] A method for preparing water-soluble chelated calcium from soybean residue degradation liquid, including the following steps:

[0035] Step 1: Add poly-soybean residue into a fermentation tank, adjust the fermentation temperature to 30-50 °C and the pH value to 7-9, and maintain for 18-30 hours to kill fermentation microorganisms, and degrade the protein in the poly-soybean residue into polypeptide amino acids;

[0036] Step 2: For the treated poly-soybean residue, in the initial stage (1-3 h) of the hydrolysis reaction, the hydrolysis degrees of different proteins are very similar. As the time prolongs, the difference gradually becomes obvious, and finally there are large differences in the hydrolysis degrees. The hydrolysis degree of alcohol washing + X enzyme is 7.67%, that of heating + X enzyme is 7.56%, that of alcohol washing + H enzyme is 7.25%, and that of X enzyme is 7.14%;

[0037] Step 3: The substrate concentration (ratio to water) is 5%, 10%, 15%, 20%, 25%. Taking the hydrolysis degree as the investigation index, determine the optimal substrate concentration. As the enzyme addition amount increases, the hydrolysis degree of soybean residue shows an upward trend. Select enzyme addition amounts of 150 U / g, 300 U / g, and 450 U / g, and conduct response surface experimental analysis on the subsequent experimental results;

[0038] Step 4: The hydrolysis degree of soybean residue is relatively high. To obtain polypeptides with high hydrolysis degree and obtain the optimal process parameters for alkaline protease X enzyme to hydrolyze soybean residue, on the basis of single-factor experiments, taking hydrolysis temperature, time, pH value, enzyme concentration, and substrate concentration as five independent variables and the hydrolysis degree of soybean residue as the response value, design a quadratic regression equation with five factors and three levels to fit the functional relationship between the factors and the index, and use the response surface analysis method to seek the optimal process parameters for enzymatic hydrolysis.

[0039] In this embodiment, according to Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 , Figure 6and Figure 7 As shown, when the substrate concentration is too high, the soybean residue becomes semi-solid, resulting in uneven hydrolysis. With substrate concentrations of 5%, 10%, 15%, 20%, and 25%, response surface experiments were conducted to determine the optimal substrate concentration. When the pH reaches 8, the degree of hydrolysis of soybean residue protein reaches the maximum because the enzyme has the highest activity under the optimal reaction pH conditions. Higher or lower than the optimal pH will affect its activity. Therefore, pH values of 7, 8, and 9 were selected for the response surface experiment. The degree of hydrolysis of soybean residue reaches the maximum at 5 h. Without fermentation, at a hydrolysis time of 24 h, the enzymatic hydrolysis reaction tends to be complete. As the enzymatic hydrolysis temperature increases, the degree of hydrolysis first increases and then decreases. When the temperature reaches 50 °C, the degree of hydrolysis of both reaches the maximum. After that, the degree of hydrolysis decreases. Temperatures of 40, 50, and 60 °C were selected for the enzymatic hydrolysis response surface experiment. As the enzymatic hydrolysis substrate decreases and the concentration decreases, the large accumulation of products has a competitive inhibition on the enzymatic hydrolysis reaction. Values of 18, 24, and 30 were selected for the enzymatic hydrolysis response surface experiment. Ethanol aqueous solution has a denaturing effect on soybean protein, changing the compact spherical shape of soybean protein into a loose structure. The degree of hydrolysis of alcohol washing + X enzyme is the highest. The results were processed using Design-Expert software, and the regression equation is as follows:

[0040] DH = +7.07 + 0.44*A + 0.22*B + 0.41*C + 0.31*D - 0.68*E + 0.59*AB + 0.80*AC - 0.16*AD + 0.60*AE + 0.67*BC + 0.37*BD - 0.12*BE + 0.05*CD - 0.32*CE - 0.34*DE - 0.16*A^2 - 0.54*B^2 - 0.51*C^2 - 0.35*D^2 - 0.11*E^2 h, Application of polypeptide amino acid chelated micro-fertilizer for crop fertilization.

[0041] Workflow of the present invention: When the method for preparing water-soluble chelated calcium using the okara degradation liquid designed by this solution is in operation, first disinfect the items to be used in advance, and then work in a suitable working area. Add okara into the fermentation tank, adjust the fermentation temperature to 30 - 50 °C, and the pH value to 7 - 9, and maintain for 18 - 30 hours to kill the fermentation microorganisms and degrade the protein in the okara into polypeptide amino acids. In the initial stage (1 - 3 h) of the hydrolysis reaction of the treated okara, the degree of hydrolysis of different proteins varies little. As time extends, the difference becomes gradually obvious, and there are significant differences in the final degree of hydrolysis. The degree of hydrolysis of alcohol washing + X enzyme is 7.67%, heating + X enzyme is 7.56%, alcohol washing + H enzyme is 7.25%, X enzyme is 7.14%, and the substrate concentration (ratio to water) is 5%, 10%, 15%, 20%, 25%. Taking the degree of hydrolysis as the index, determine the optimal substrate concentration. As the enzyme dosage increases, the degree of hydrolysis of okara shows an upward trend. Select enzyme dosages of 150 U / g, 300 U / g, and 450 U / g for response surface experimental analysis of the subsequent experimental results. The degree of hydrolysis of okara is relatively high. To obtain polypeptides with a high degree of hydrolysis and obtain the optimal process parameters for alkaline protease X enzyme to hydrolyze okara, based on the single-factor experiment, taking the hydrolysis temperature, time, pH value, enzyme concentration, and substrate concentration as the independent variables and the degree of hydrolysis of okara as the response value, design a quadratic regression equation with 5 factors and 3 levels to fit the functional relationship between the factors and the index, and use the response surface analysis method to seek the optimal process parameters for enzymatic hydrolysis. When the substrate concentration is too high, the okara becomes semi-solid, resulting in uneven hydrolysis. Taking the substrate concentration as 5%, 10%, 15%, 20%, 25%, conduct a response surface experiment to determine the optimal substrate concentration. When the pH reaches 8, the degree of hydrolysis of okara protein reaches the maximum because the enzyme has the highest activity under the optimal reaction pH condition, and being greater than or less than the optimal pH will affect its activity. Therefore, select pH 7, 8, and 9 for the response surface experiment. The degree of hydrolysis of okara reaches the maximum at 5 h. Without fermentation, at a hydrolysis time of 24 h, the enzymatic hydrolysis reaction tends to be complete. As the hydrolysis temperature increases, the degree of hydrolysis first increases and then decreases. When the temperature reaches 50 °C, the degree of hydrolysis of both proteins reaches the maximum. After 50 °C, the degree of hydrolysis decreases. Select 40, 50, and 60 °C for the enzymatic hydrolysis response surface experiment. The enzymatic hydrolysis substrate decreases, the concentration decreases, and the large accumulation of products has a competitive inhibition on the enzymatic hydrolysis reaction. Select 18, 24, and 30 for the enzymatic hydrolysis response surface experiment. Ethanol aqueous solution has a denaturing effect on soybean protein, changing the compact spherical shape of soybean protein into a loose structure. The degree of hydrolysis of alcohol washing + X enzyme is the highest. Application of polypeptide amino acid chelated micro-fertilizer for crop fertilization. In the example figure, A, B, C, D, E - represent time (h), temperature (°C), pH, enzyme dosage (U / g), and substrate concentration (%) respectively. The DH model Prob>F value is less than 0.05. It can be seen from the single-factor analysis that at a temperature of 50 °C, a time of 24 h, an enzyme concentration of 300 u / g, a pH value of 8, and a substrate concentration of about 10%, the degree of hydrolysis of soybean dregs is relatively high. To obtain polypeptides with a high degree of hydrolysis and obtain the optimal process parameters for the hydrolysis of soybean dregs by alkaline protease X enzyme, on the basis of the single-factor experiment, with the five factors of hydrolysis temperature, time, pH value, enzyme concentration, and substrate concentration as independent variables and the degree of hydrolysis of soybean dregs as the response value, it is shown that the model is significant. The lack-of-fit term of the model represents the probability that the predicted value of the model does not conform to the actual value. The determination coefficient R2 of the model is 0.9319, which is greater than 0.9, indicating that the model fitting degree is very good. At the same time, the coefficient of variation (CV) value is 7.07, indicating that the model equation can well reflect the true experimental values. Therefore, this model can be used to analyze the changes in the response value.

[0042] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing water-soluble chelated calcium from bean dregs degradation liquid, comprising the following steps: Step 1: Add the polysoy dregs into the fermentation tank, adjust the fermentation temperature to 30-50°C, adjust the pH value to 7-9, and keep it for 18-30 hours to kill the fermentation microorganisms and degrade the protein in the polysoy dregs into polypeptide amino acids; Step 2: In the initial stage (1-3h) of the hydrolysis reaction of the treated polysoy dregs, the hydrolysis degrees of different proteins are very different. As time goes by, the difference becomes more obvious. The final hydrolysis degrees are quite different, with alcohol washing + X enzyme being 7.67%, heating + X enzyme being 7.56%, alcohol washing + H enzyme being 7.25%, and X enzyme being 7.14%; Step 3: The substrate concentration (water ratio) was 5%, 10%, 15%, 20%, and 25%. The hydrolysis degree was used as the investigation index to determine the optimal substrate concentration. With the increase of the enzyme addition amount, the hydrolysis degree of okara showed an upward trend. The enzyme addition amounts of 150U / g, 300U / g, and 450U / g were selected, and the response surface experimental analysis of the subsequent experimental results was carried out; Step 4: The hydrolysis degree of bean dregs is relatively high. In order to obtain polypeptides with a high degree of hydrolysis, the optimal process parameters for enzymatic hydrolysis of bean dregs with alkaline protease X were obtained. Based on the single factor experiment, the five factors of hydrolysis temperature, time, pH value, enzyme concentration and substrate concentration were used as independent variables, and the hydrolysis degree of bean dregs was used as the response value. A quadratic regression equation with five factors and three levels was designed to fit the functional relationship between the factors and the indicators, and the response surface analysis method was used to seek the optimal process parameters for enzymatic hydrolysis.

2. The method for preparing water-soluble chelated calcium from dregs degradation liquid according to claim 1, characterized in that: The substrate concentration is too high, causing the bean dregs to be semi-solid and uneven hydrolysis. The optimal substrate concentration is determined by response surface experiments with substrate concentrations of 5%, 10%, 15%, 20% and 25%.

3. The method for preparing water-soluble chelated calcium from dregs degradation liquid according to claim 1, characterized in that: When the pH reaches 8, the degree of hydrolysis of okara protein reaches the maximum, because the activity of the enzyme is maximum under the optimal reaction pH conditions, and a pH greater than or less than the optimal pH will affect its activity. Therefore, pH 7, 8, and 9 were selected for the response surface experiment.

4. The method for preparing water-soluble chelated calcium from dregs degradation liquid according to claim 1, characterized in that: The degree of hydrolysis of the okara reaches the maximum at 5 hours, and the enzymatic hydrolysis reaction is almost complete when the unfermented hydrolysis time is 24 hours.

5. The method for preparing water-soluble chelated calcium from dregs degradation liquid according to claim 1, characterized in that: As the enzymatic hydrolysis temperature increases, the hydrolysis degree increases first and then decreases. When the temperature reaches 50°C, the hydrolysis degrees of both proteins reach the maximum value.

6. The method for preparing water-soluble chelated calcium from bean dregs degradation liquid according to claim 5, characterized in that: The hydrolysis degree increases and decreases after 50°C, and 40, 50, and 60°C are selected to carry out the enzymatic hydrolysis response surface experiment.

7. The method for preparing water-soluble chelated calcium from dregs degradation liquid according to claim 4, characterized in that: The enzymatic substrate was reduced, the concentration was lowered, and the large amount of product accumulation produced competitive inhibition on the enzymatic reaction. 18, 24, and 30 were selected for enzymatic response surface experiments.

8. The method for preparing water-soluble chelated calcium from dregs degradation liquid according to claim 1, characterized in that: The ethanol aqueous solution has a denaturing effect on the soybean protein, and the compact spherical shape of the soybean protein is changed into a loose structure. The hydrolysis degree of alcohol washing + X enzyme is the highest.

9. The method for preparing water-soluble chelated calcium from dregs degradation liquid according to claim 1, characterized in that: The results were processed using Design-Expert software, and the regression equation was as follows: DH=+7.07+0.44*A+0.22* B+0.41*C+0.31*D-0.68*E+0.59*AB+0.80*AC-0.16*AD+0.60*AE+0.67*BC+0.37*BD-0.1 2*BE+0.05*CD-0.32*CE-0.34*DE-0.16*A^2-0.54*B^2-0.51*C^2-0.35*D^2-0.11*E^2h.

10. The method for preparing water-soluble chelated calcium from okara degradation liquid according to claim 1, characterized in that: The polypeptide amino acid chelated micro-fertilizer is used for fertilizing crops.

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