Agricultural glucan and method for preparing a fertilizer thereof
By enzymatically hydrolyzing and homogenizing yeast cell walls, and using specific enzymes, a dextran fertilizer suitable for agriculture was prepared. This solved the problem of insufficient application of dextran in agriculture, improved the extraction rate and the effect of promoting crop growth, and ensured the stability of the product.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- DRYLAND AGRI INST GANSU ACADEMY OF AGRI SCI
- Filing Date
- 2023-06-09
- Publication Date
- 2026-05-29
AI Technical Summary
In current technologies, dextran is rarely used in agriculture, especially as a fertilizer, and the extraction rate is low, the quality is unstable, and it is difficult to effectively promote crop growth.
Yeast cell walls were enzymatically hydrolyzed using alkaline protease and β-glucanase, combined with α-mannosidase treatment, and then separated and homogenized to prepare a glucan suitable for agriculture. The drying temperature was controlled to maintain quality stability.
It improves the extraction rate of dextran and its application effect in agriculture, promotes crop growth, and ensures stable product quality, avoiding color changes during storage.
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Abstract
Description
Technical Field
[0001] This invention relates to a method for preparing agricultural dextran and its fertilizer. Background Technology
[0002] β-glucan can effectively regulate the body's immune function and promote the production of IgM antibodies in the body. Therefore, it is widely used in food to improve the immunity of humans and animals.
[0003] Currently, the technology for preparing β-glucan by enzymatic hydrolysis of yeast cell walls is relatively mature. For example, the patent publication number CN101184780A, entitled "Preparation of β-glucan and mannan," uses alkaline protease to hydrolyze yeast cell walls to obtain components rich in glucan and components rich in mannan. Alternatively, after hydrolyzing yeast cell walls with alkaline protease, a further enzyme incubation step (b) using at least one of amylase, lipase, or combinations thereof is performed to obtain protease-treated cell walls. Its applications are food supplements, pharmaceuticals, cosmetics, or nutritional supplements; or animal feed, but it has not been applied in agriculture.
[0004] Patent CN 109207384A, entitled "Modified Yeast Cell Wall and Its Preparation Method and Application," discloses a method for obtaining yeast cell walls by enzymatic hydrolysis of yeast cell wall emulsion with mannanase, alkaline protease, papain, cellulase, and β-glucanase, followed by drying. Its application is in the field of feed additives.
[0005] It is evident that dextran has been widely used in humans and animals, but its application in plants is rarely reported. However, the application of dextran in agriculture has more requirements, such as stable quality and the ability to better promote crop growth.
[0006] Currently, there are few glucans used in agriculture, especially in fertilizers. Therefore, the market needs an agricultural glucan that can be adapted to agricultural applications. Summary of the Invention
[0007] This invention provides a method for preparing agricultural dextran and its fertilizer, and solves the technical problems of 1) improving the extraction rate of agricultural dextran; 2) preparing dextran suitable for agriculture, which can promote crop growth; and 3) maintaining the quality stability of the prepared agricultural dextran.
[0008] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:
[0009] A method for preparing agricultural dextran, comprising the following steps:
[0010] 1) The yeast cell walls are enzymatically hydrolyzed in water, and the enzymes are inactivated before separation to obtain the hydrolysate and residue;
[0011] 2) Add the residue obtained in step 1) to water, homogenize, add enzyme for secondary enzymatic hydrolysis, inactivate the enzyme, and separate to obtain agricultural dextran solution and residue 2.
[0012] The enzyme used for enzymatic hydrolysis in step 1) is alkaline protease;
[0013] The enzyme added in step 2) is β-glucanase.
[0014] Step 2) also includes the addition of α-mannosidase.
[0015] The α-mannosidase is one or two of α-1,3-mannosidase, α-1,2-mannosidase, or α-1,6-mannosidase.
[0016] In step 1), the mass ratio of yeast cell wall, enzyme, and water is 7–20:0.001–0.006:80–92.999.
[0017] The enzymatic hydrolysis conditions are pH 8.5–11, temperature 40–55℃, and time 8–24 h; the enzyme inactivation conditions are temperature 90–100℃ and time 1–3 min.
[0018] The homogenization conditions described in step 2) are a pressure of 4–10 MPa and a temperature of 50–70 °C.
[0019] In step 2), the mass ratio of residue, enzyme, and water is 7–20:0.001–0.006:80–92.999.
[0020] The enzymatic hydrolysis conditions are pH 4.5–6, temperature 40–55℃, and time 8–24 h; the enzyme inactivation conditions are temperature 90–100℃ and time 1–3 min.
[0021] This also includes drying the dextran solution to obtain agricultural dextran powder;
[0022] The drying temperature shall not exceed 85°C.
[0023] Agricultural glucan can be used directly as fertilizer, or
[0024] Agricultural glucan is added to fertilizer and used together with the fertilizer.
[0025] The invention has the following beneficial technical effects:
[0026] 1) In this application, the dextran prepared by enzymatic hydrolysis of protease is further hydrolyzed by adding dextranase to prepare dextran suitable for agricultural use. Compared with dextran that has only been hydrolyzed by protease, the agricultural dextran can promote crop growth more significantly.
[0027] 2) This application employs homogenization of the residue under pressure of 4-10 MPa and temperature of 50-70℃. The purpose is to change the helical structure of dextran. This is because dextran has multiple hydroxyl groups in its molecule. Due to the interaction of hydrogen bonds, the three polysaccharide chains are arranged in parallel and intertwined to form a dense triple helix. Homogenization converts the triple helix into a single chain, thereby increasing the dextran content in agricultural dextran solution.
[0028] 3) This application requires separating the hydrolysate after alkaline protease hydrolysis and then performing dextranase hydrolysis. If the hydrolysate is not separated, the prepared agricultural dextran solution will have a low dextran content and will change color during storage, resulting in unstable product quality.
[0029] 4) This application dries the dextran, limiting the drying temperature to no more than 85°C, in order to prevent the dextran from carbonizing during the drying process and affecting its application in agriculture. Detailed Implementation
[0030] To better understand the above technical solutions, the technical solutions of the present invention will be described in detail below with reference to preferred examples. Example 1
[0031] A method for preparing agricultural dextran, comprising the following steps:
[0032] 1) The yeast cell walls are enzymatically hydrolyzed in water, and the enzymes are inactivated before separation to obtain the hydrolysate and residue;
[0033] 2) Add all the residue obtained in step 1) to water, homogenize, add enzyme for secondary enzymatic hydrolysis, inactivate the enzyme, and separate to obtain agricultural dextran solution and residue 2.
[0034] The enzyme used for enzymatic hydrolysis in step 1) is alkaline protease;
[0035] The enzyme added in step 2) is β-glucanase, which is a combination of β-1,6-glycosidase and β-1,3-glycosidase in a mass ratio of 1:3.
[0036] In step 1), the mass ratio of yeast cell wall, enzyme and water is 8 (g): 0.001 (g): 91.999 (g).
[0037] The enzymatic hydrolysis conditions were pH 10, temperature 50℃, and time 12h; the enzyme inactivation conditions were temperature 95℃ and time 2min.
[0038] The homogenization conditions described in step 2) are a pressure of 6 MPa and a temperature of 60°C.
[0039] In step 2), the mass ratio of residue, enzyme, and water is 8:0.001:91.999.
[0040] The enzymatic hydrolysis conditions were pH 5, temperature 45℃, and time 12h; the enzyme inactivation conditions were temperature 95℃ and time 2min.
[0041] The dextran solution was dried in a 60°C forced-air oven to obtain agricultural dextran powder, which weighed 2.47g.
[0042] The total glucan content of agricultural glucan powder was determined by the GOPOD method. The total glucan content was 2.27g, accounting for 28.4% of the yeast cell wall mass, and the extraction rate was 96.0%. Example 2
[0043] A method for preparing agricultural dextran, comprising the following steps:
[0044] 1) The yeast cell walls are enzymatically hydrolyzed in water, and the enzymes are inactivated before separation to obtain the hydrolysate and residue;
[0045] 2) Add all the residue obtained in step 1) to water, homogenize, add enzyme for secondary enzymatic hydrolysis, inactivate the enzyme, and separate to obtain agricultural dextran solution and residue 2.
[0046] The enzyme used for enzymatic hydrolysis in step 1) is alkaline protease;
[0047] The enzyme added in step 2) is a combination of β-glucanase and α-mannosidase in a mass ratio of 1:1.
[0048] The β-glucanase is a composition of β-1,6-glycosidase and β-1,3-glycosidase in a mass ratio of 1:3.
[0049] The α-mannosidase is a combination of α-1,6-mannosidase and α-1,3-mannosidase in a mass ratio of 1:1.
[0050] In step 1), the mass ratio of yeast cell wall, enzyme and water is 8 (g): 0.001 (g): 91.999 (g).
[0051] The enzymatic hydrolysis conditions were pH 10, temperature 50℃, and time 12h; the enzyme inactivation conditions were temperature 95℃ and time 2min.
[0052] The homogenization conditions described in step 2) are a pressure of 6 MPa and a temperature of 60°C.
[0053] In step 2), the mass ratio of residue, enzyme, and water is 8:0.002:91.998.
[0054] The enzymatic hydrolysis conditions were pH 5, temperature 45℃, and time 12h; the enzyme inactivation conditions were temperature 95℃ and time 2min.
[0055] The dextran solution was dried in a 60°C forced-air oven to obtain agricultural dextran powder, which weighed 4.65g.
[0056] The total glucan and total mannan content of agricultural glucan powder were determined using the GOPOD method. The total glucan content was 2.28 g, and the total mannan content was 1.76 g. The total glucan content accounted for 28.5% of the yeast cell wall mass, with an extraction rate of 96.3%. The total mannan content accounted for 22.0% of the yeast cell wall mass, with an extraction rate of 71.4%. Example 3
[0057] A method for preparing agricultural dextran, comprising the following steps:
[0058] 1) The yeast cell walls are enzymatically hydrolyzed in water, and the enzymes are inactivated before separation to obtain the hydrolysate and residue;
[0059] 2) Add all the residue obtained in step 1) to water, homogenize, add enzyme for secondary enzymatic hydrolysis, inactivate the enzyme, and separate to obtain agricultural dextran solution and residue 2.
[0060] The enzyme used for enzymatic hydrolysis in step 1) is alkaline protease;
[0061] The enzyme added in step 2) is β-glucanase, which is composed of β-1,6-glycosidase and β-1,3-glycosidase in a mass ratio of 1:2.
[0062] In step 1), the mass ratio of yeast cell wall, enzyme, and water is 12 (g): 0.002 (g): 87.998 (g).
[0063] The enzymatic hydrolysis conditions were pH 9, temperature 55℃, and time 14h; the enzyme inactivation conditions were temperature 98℃ and time 2min.
[0064] The homogenization conditions described in step 2) are a pressure of 5 MPa and a temperature of 65°C.
[0065] In step 2), the mass ratio of residue, enzyme, and water is 12:0.002:87.998.
[0066] The enzymatic hydrolysis conditions were pH 5.2, temperature 47℃, and time 13h; the enzyme inactivation conditions were temperature 95℃ and time 2min.
[0067] The dextran solution was dried in a 60°C forced-air oven to obtain agricultural dextran powder, which weighed 3.51g.
[0068] The total glucan content of agricultural glucan powder was determined by the GOPOD method. The total glucan content was 3.40 g, accounting for 28.3% of the yeast cell wall mass, and the extraction rate was 95.6%. Example 4
[0069] A method for preparing agricultural dextran, comprising the following steps:
[0070] 1) The yeast cell walls are enzymatically hydrolyzed in water, and the enzymes are inactivated before separation to obtain the hydrolysate and residue;
[0071] 2) Add all the residue obtained in step 1) to water, homogenize, add enzyme for secondary enzymatic hydrolysis, inactivate the enzyme, and separate to obtain agricultural dextran solution and residue 2.
[0072] The enzyme used for enzymatic hydrolysis in step 1) is alkaline protease;
[0073] The enzyme added in step 2) is a combination of β-glucanase and α-mannosidase in a mass ratio of 1:1.
[0074] The β-glucanase is a combination of β-1,6-glycosidase and β-1,3-glycosidase in a mass ratio of 1:1.
[0075] The α-mannosidase is a composition of α-1,6-mannosidase, α-1,3-mannosidase and α-1,2-mannosidase in a mass ratio of 2:1:1.
[0076] In step 1), the mass ratio of yeast cell wall, enzyme, and water is 10:0.002:89.998 (g).
[0077] The enzymatic hydrolysis conditions were pH 10.5, temperature 50℃, and time 10h; the enzyme inactivation conditions were temperature 100℃ and time 1min.
[0078] The homogenization conditions described in step 2) are a pressure of 8 MPa and a temperature of 55°C.
[0079] In step 2), the mass ratio of residue, enzyme, and water is 12:0.002:87.998.
[0080] The enzymatic hydrolysis conditions were pH 5.2, temperature 51℃, and time 12h; the enzyme inactivation conditions were temperature 98℃ and time 2min.
[0081] The dextran solution was dried in a vacuum oven at 50°C and 0.7 MPa to obtain agricultural dextran powder, which weighed 6.27 g.
[0082] The total glucan content of agricultural glucan powder was determined by the GOPOD method. The total glucan content was 2.88 g, and the total mannan content was 3.01 g. The total glucan mass accounted for 28.8% of the yeast cell wall mass, with an extraction rate of 97.3%; the total mannan mass accounted for 30.1% of the yeast cell wall mass, with an extraction rate of 97.7%.
[0083] The total glucan content in the yeast cell walls used in the experiment was 29.6%, and the total mannan content was 30.8%. Example 5
[0084] Agricultural dextran solution is used as fertilizer in agriculture.
[0085] When agricultural dextran solution is used as a foliar fertilizer, it needs to be diluted with water 8-15 times before use.
[0086] When agricultural dextran solution is used as a water-soluble fertilizer in drip irrigation, it needs to be diluted with water 6-8 times before use. Example 6
[0087] Agricultural dextran powder is added to fertilizer to obtain fertilizer containing agricultural dextran;
[0088] The fertilizer includes one of the following: compound fertilizer, blended fertilizer, water-soluble fertilizer, organic-inorganic fertilizer, and organic fertilizer. Example 7
[0089] Agricultural dextran solution is added to fertilizer to obtain fertilizer containing agricultural dextran;
[0090] The fertilizer includes one of the following: compound fertilizer, blended fertilizer, water-soluble fertilizer, organic-inorganic fertilizer, and organic fertilizer.
[0091] Comparative Example 1 (except for the lack of homogenization, the preparation method was the same as in Example 1), the agricultural dextran powder prepared therein weighed 2.32g, the total dextran content was 2.11g, accounting for 26.4% of the yeast cell wall mass, and the extraction rate was 89.2%;
[0092] Comparative Example 2 (except that the enzymatic hydrolysate prepared in step 1 was not separated, the other preparation methods were the same as in Example 1) The agricultural dextran powder prepared therein weighed 2.35g, the total dextran content was 2.16g, accounting for 27.4% of the yeast cell wall mass, and the extraction rate was 92.6%.
[0093] Comparative Example 3 (except that the enzymatic hydrolysate prepared in step 1 was not separated and homogenized, the other preparation methods were the same as in Example 1) The agricultural dextran powder prepared therein weighed 2.32g, the total dextran content was 2.10g, accounting for 26.3% of the yeast cell wall mass, and the extraction rate was 89.0%.
[0094] The agricultural dextran solutions prepared in Examples 1 to 4, Comparative Examples 1 and 2 were poured into 1L polyethylene bottles, sealed, and stored for one month and three months, respectively. The color changes were observed, with the initial color being the color immediately after production, as shown in Table 1.
[0095]
[0096] Note: The enzymatic hydrolysates isolated from Comparative Example 1 and Examples 1 to 4 were also sealed and stored. No obvious color change was observed within three months.
[0097] The extraction rate data of dextran in Example 1, Comparative Example 1, and Comparative Example 2, along with the color changes during the storage of agricultural dextran solution, reveal that homogenization can increase the content of water-soluble dextran in the agricultural dextran solution. However, Comparative Example 2 shows that while homogenization can increase the dextran content, it also causes color changes during storage, affecting product quality. To clarify the cause of the color change, the applicant conducted an experiment in Comparative Example 3. Although color changes also occurred, they were significantly delayed. Therefore, the applicant believes that the increased temperature and pressure during homogenization accelerated the color change.
[0098] Separating the enzymatic hydrolysate prepared in step 1) can effectively solve the problem of color change during the storage of agricultural dextran solution.
[0099] The following experimental data further illustrates the beneficial effects of the present invention:
[0100] Test materials
[0101] 1.1 Test location: Jingzhi Town, Anqiu City, Weifang City.
[0102] 1.2 Experimental Detection: SPAD (chlorophyll content) of potato leaves, including before and after treatment, and the average value was taken;
[0103] 1.3 Experimental Methods: Four plots were selected, with 30 potato plants in each plot. The agricultural dextran solutions prepared by Comparative Example 1 (except for homogenization, the preparation methods were the same as in Example 1), Example 1 and Example 2, and Comparative Example 5 (the residue prepared by step 1 of Example 1) were tested. The agricultural dextran solution was diluted 10 times with water and sprayed onto the potato leaves using a sprayer. 1 L of diluted agricultural dextran solution was sprayed per plot. The residue prepared by Comparative Example 5 (the residue prepared by step 1 of Example 1) was applied by hole application. 1 kg of residue was evenly applied to the roots of the tested potatoes at a depth of 8 cm.
[0104] 1.4 Detection method: SPAD detector was used for detection, and the average value was taken.
[0105] Before treatment refers to the day on which each treatment was applied in the experiment, and after treatment refers to the 5th day after each treatment was applied, during which SPAD testing was performed.
[0106] Except for the different processing steps, all other implementations of this application are the same.
[0107] 2 Results and Analysis
[0108] The average SPAD values for each treatment are shown in Table 2.
[0109]
[0110] Comparing the data of Comparative Example 5 (where the residue prepared in step 1 of Example 1 was applied by hole application, i.e., 1 kg of residue was applied evenly to the roots of the tested potato at a depth of 8 cm) with that of Example 1 in Table 2, it can be seen that the agricultural dextran prepared in Example 1 of this application has a better effect on agriculture.
[0111] Comparing Comparative Example 1 (which was prepared in the same way as Example 1 except that it was not homogenized) with Example 1, it can be seen that the agricultural dextran prepared by homogenization in Example 1 can better promote crop growth when applied to agriculture.
Claims
1. A method for preparing agricultural dextran, characterized in that, The following steps are performed: 1) The yeast cell wall is enzymatically hydrolyzed in water, and after enzyme inactivation, the hydrolysate and residue are separated; 2) The residue obtained in step 1) is added to water for homogenization, and an enzyme is added for secondary enzymatic hydrolysis. After enzyme inactivation, the agricultural dextran solution and residue 2 are separated; The enzyme used for enzymatic hydrolysis in step 1) is alkaline protease; The enzyme added for enzymatic hydrolysis in step 2) is β-glucanase; The homogenization conditions in step 2) are a pressure of 4-10 MPa and a temperature of 50-70℃.
2. The method for preparing agricultural dextran as described in claim 1, characterized in that, Step 2) also includes the addition of α-mannosidase.
3. The method for preparing agricultural dextran as described in claim 2, characterized in that, The α-mannosidase is one or two of α-1,3-mannosidase, α-1,2-mannosidase, or α-1,6-mannosidase.
4. The method for preparing agricultural dextran as described in claim 1, characterized in that, In step 1), the mass ratio of yeast cell wall, enzyme, and water is 7–20:0.001–0.006:80–92.999; the enzymatic hydrolysis conditions are pH 8.5–11, temperature 40–55℃, and time 8–24 h; the enzyme inactivation conditions are temperature 90–100℃ and time 1–3 min.
5. The method for preparing agricultural dextran as described in claim 1, characterized in that, In step 2), the mass ratio of residue, enzyme, and water is 7–20:0.001–0.006:80–92.999; the enzymatic hydrolysis conditions are pH 4.5–6, temperature 40–55℃, and time 8–24 h; the enzyme inactivation conditions are temperature 90–100℃ and time 1–3 min.
6. The method for preparing agricultural dextran according to any one of claims 1 to 5, characterized in that, It also includes drying the dextran solution to obtain agricultural dextran powder; the drying temperature does not exceed 85°C.
7. The method for preparing agricultural dextran according to any one of claims 1 to 5, characterized in that, Agricultural dextran can be used directly as fertilizer, or added to fertilizer for use together; the agricultural dextran includes one or both of agricultural dextran liquid and agricultural dextran powder.