Preparation method of glutamic acid bacterial cell protein ecological fertilizer

Abstract

The application discloses a preparation method of glutamic acid bacterial protein ecological fertilizer, and the preparation steps are as follows: firstly, zinc polysilicate is added into glutamic acid fermentation waste liquid, and bacterial protein-zinc polysilicate complex is obtained through filtration; then, zinc silicate and hydroxyapatite are added, and amino acid composite hydroxyapatite particles are formed through the action of citric acid; and finally, urea-humic acid-dipotassium hydrogen phosphate complex is sprayed on the amino acid composite hydroxyapatite particles to obtain the ecological fertilizer. The ecological fertilizer can not only fully utilize the bacterial protein in the glutamic acid fermentation waste liquid, but also play a good slow-release effect of nitrogen, phosphorus and other elements through the action of two complexes. In addition, the addition of silicon and zinc elements can play a supplementing effect for the growth of crops, so that the fertilizer has the dual functions of environmental protection and long-acting slow release, and has a good promoting effect on the growth of crops.

Description

Technical fields:

[0001] This invention relates to the field of eco-fertilizers, and more specifically to a method for preparing glutamic acid bacterial protein eco-fertilizer. Background technology:

[0002] Glutamic acid is an organic compound, chemically named α-aminoglutarate. It is an amino acid widely found in nature. Glutamic acid is an important substance in protein metabolism and also one of the important neurotransmitters in the human body. In the food industry, monosodium glutamate (MSG) is used as a flavoring agent to enhance the umami flavor of food; it is the main component of commonly used seasonings.

[0003] The fermentation of glutamic acid by Corynebacterium glutamicum is a standard method in the industry, but the wastewater discharged during monosodium glutamate (MSG) production is a type of industrial wastewater that is very difficult to treat. Due to the inability to effectively treat MSG wastewater, many MSG factories have been listed as key pollution sources nationwide, and the treatment of MSG wastewater has become a major problem restricting the development of MSG production enterprises.

[0004] Glutamic acid bacterial protein is a major byproduct of monosodium glutamate (MSG) production. To save production costs and avoid wasting usable resources, most MSG manufacturers currently choose to extract glutamic acid bacterial protein from wastewater and use it in the production of animal feed or organic fertilizer. Bacterial protein represents a comprehensive utilization of waste resources, with relatively low costs and significant economic benefits; therefore, its development and utilization have broad prospects.

[0005] Patent CN110734331B discloses a compound fertilizer prepared using glutamic acid fermentation waste, which is prepared according to the following steps: Step 1) preparing amino acid chelated granules; Step 2) preparing urea-humic acid complex; Step 3) preparing compound fertilizer. This method of preparing compound fertilizer has the following drawbacks: (1) The presence of a large amount of sulfates such as manganese sulfate and zinc sulfate in the amino acid metal chelate solution will still lead to soil compaction to a certain extent; (2) Directly centrifuging and collecting the bacterial protein from the glutamic acid fermentation liquid and then performing metal chelation cannot achieve complete resource utilization.

[0006] Therefore, it is particularly important to develop an ecological fertilizer that can both provide slow release and improve the utilization efficiency of microbial protein. Summary of the Invention:

[0007] This invention aims to provide a method for preparing a glutamic acid microbial protein eco-fertilizer, with the goal of developing an eco-fertilizer that can both provide slow release and improve the utilization efficiency of microbial protein.

[0008] To achieve the technical objective of this invention, the following technical solution is adopted to prepare ecological fertilizer: First, zinc polysilicate is added to glutamic acid fermentation waste liquid, and the mixture is filtered to obtain a microbial protein-zinc polysilicate complex; zinc silicate and hydroxyapatite are added, and amino acid composite hydroxyapatite particles are formed through the action of citric acid; urea-humic acid-dipotassium hydrogen phosphate complex is sprayed onto the amino acid composite hydroxyapatite particles to obtain ecological fertilizer.

[0009] This invention provides a method for preparing a glutamic acid microbial protein ecological fertilizer, the preparation steps of which are as follows:

[0010] Step (1): Add zinc polysilicate to the glutamic acid fermentation waste liquid, mix for 1-2 hours, centrifuge and filter, collect the filtrate, dry and grind the filtrate to obtain the bacterial protein-zinc polysilicate complex.

[0011] Step (2): Prepare a zinc silicate aqueous solution and add the bacterial protein-polyzinc silicate complex prepared in step (1) to it; add citric acid, adjust the pH value to 6.0-7.0, stir and react for 1-2 hours, add hydroxyapatite, and at the same time supplement citric acid, continue to adjust the pH value to 6.0-7.0, continue to stir and react for 1-2 hours, and then centrifuge and filter to obtain amino acid composite hydroxyapatite particles;

[0012] Step (3): Preparation of urea-humic acid-dipotassium hydrogen phosphate complex;

[0013] Step (4): Spray the urea-humic acid-dipotassium hydrogen phosphate complex onto the amino acid composite hydroxyapatite particles, stir evenly, and dry at 40-60℃ to obtain the ecological fertilizer.

[0014] Furthermore, in step (1), the ratio of the amount of zinc polysilicate added to the waste liquid is 1.5-3 g / L.

[0015] Furthermore, the concentration of the zinc silicate aqueous solution prepared in step (2) is 0.03-0.1 mol / L, and the ratio of the amount of complex added to the zinc silicate aqueous solution is 30-100 g / L.

[0016] Furthermore, in step (2), the amount of hydroxyapatite added is 2-4 times that of the complex.

[0017] Further, the specific preparation steps of the urea-humic acid-dipotassium hydrogen phosphate complex are as follows: urea and water are added to a stirrer at a weight ratio of 1:(2-3), the temperature is raised to 30-35℃, and the mixture is stirred evenly. Then, humic acid and dipotassium hydrogen phosphate are added, and the temperature is raised to 70-90℃ for stirring reaction to obtain the urea-humic acid-dipotassium hydrogen phosphate complex.

[0018] Furthermore, the weight ratio of humic acid to urea is 1:(5-7); the weight ratio of dipotassium hydrogen phosphate to urea is 1:(6-10).

[0019] Furthermore, in step (4), the mass ratio of the urea-humic acid-potassium dihydrogen phosphate complex to the amino acid chelate particles is 1L:(3-5)kg.

[0020] In this invention, zinc polysilicate is added during the extraction of microbial protein. Firstly, zinc polysilicate, as a non-toxic material, can be added as a component. Secondly, as a flocculant, zinc polysilicate can be used to extract as much microbial protein as possible from the fermentation waste liquid. Then, the complexing function of zinc silicate with protein is utilized to form a complex, thereby improving the slow-release effect of the ecological fertilizer. Thirdly, silicon and zinc are both high-quality trace elements in fertilizers, which can supplement the growth of crops.

[0021] This invention utilizes urea, humic acid, and dipotassium hydrogen phosphate to prepare a complex that simultaneously replenishes nitrogen, phosphorus, and potassium elements to the soil and crops. Furthermore, the complex formed by these three materials also provides a degree of slow-release effect.

[0022] This invention further adds zinc silicate to the microbial protein-zinc polysilicate complex and hydrolyzes the protein with citric acid to increase the complexation effect between amino acids and zinc silicate. Hydroxyapatite is then added and treated again with citric acid to create porosity on the surface of the hydroxyapatite, further enhancing the complexation effect between amino acids and hydroxyapatite, thereby improving the slow-release effect of the organic fertilizer. Simultaneously, by using hydroxyapatite as the carrier particle, it can continuously replenish phosphorus to the soil.

[0023] Compared with existing technologies, the ecological fertilizer of this invention can fully utilize the microbial protein in glutamic acid fermentation waste liquid, and the two complexes can achieve a good slow-release effect of nitrogen, phosphorus and other elements. In addition, the addition of silicon and zinc can supplement the growth of crops. Thus, the fertilizer of this invention has the dual effects of being environmentally friendly and having a long-lasting slow-release effect, and has a good promoting effect on the growth of crops. Detailed implementation method:

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention are further described below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely for the purpose of helping to understand the technical content and effects of this invention and should not be considered as limitations on this invention.

[0025] This invention comprises two embodiments and two comparative examples.

[0026] Example 1:

[0027] Step (1): Add zinc polysilicate to the glutamic acid fermentation waste liquid, mix for 2 hours, centrifuge and filter, collect the filtrate, dry and grind the filtrate to obtain the microbial protein-zinc polysilicate complex; 2g of zinc polysilicate is added to each 1L of fermentation waste liquid;

[0028] Step (2): Prepare a 0.05 mol / L zinc silicate aqueous solution, add the bacterial protein-polyzinc silicate complex prepared in step (1) to it, the ratio of the amount of complex added to the zinc silicate aqueous solution is 50 g / L; add citric acid, adjust the pH value to 6.0, stir and react for 1 h, add hydroxyapatite with 3 times the mass of the complex, while supplementing citric acid, continue to adjust the pH value to 6.0, continue to stir and react for 1 h, then centrifuge and filter to obtain amino acid composite hydroxyapatite particles;

[0029] Step (3): Add urea, humic acid, and dipotassium hydrogen phosphate to prepare a urea-humic acid-dipotassium hydrogen phosphate complex. The specific preparation steps are as follows: add 1 part by mass of urea and 2 parts by mass of water to a stirrer, heat to 30°C, stir evenly, then add humic acid and dipotassium hydrogen phosphate, raise the temperature to 80°C and stir to react, and obtain the urea-humic acid-dipotassium hydrogen phosphate complex. The weight ratio of humic acid to urea is 1:6; the weight ratio of dipotassium hydrogen phosphate to urea is 1:8.

[0030] Step (4): Spray 1L of urea-humic acid-dipotassium hydrogen phosphate complex onto 4Kg of amino acid composite hydroxyapatite particles, stir evenly, and dry at 40℃ to obtain ecological fertilizer.

[0031] Example 2:

[0032] Step (1): Add zinc polysilicate to the glutamic acid fermentation waste liquid, mix for 2 hours, then centrifuge and filter, collect the filtrate, dry and grind the filtrate to obtain the microbial protein-zinc polysilicate complex; wherein 2.5g of zinc polysilicate is added to each 1L of fermentation waste liquid;

[0033] Step (2): Prepare a 0.05 mol / L zinc silicate aqueous solution, add the bacterial protein-polyzinc silicate complex prepared in step (1) to it, the ratio of the amount of complex added to the zinc silicate aqueous solution is 80 g / L; add citric acid, adjust the pH value to 7.0, stir and react for 1 h, add hydroxyapatite with 3 times the mass of the complex, while supplementing citric acid, continue to adjust the pH value to 7.0, continue to stir and react for 1 h, then centrifuge and filter to obtain amino acid composite hydroxyapatite particles;

[0034] Step (3): Add urea, humic acid, and dipotassium hydrogen phosphate to prepare a urea-humic acid-dipotassium hydrogen phosphate complex. The specific preparation steps are as follows: add 1 part by mass of urea and 2 parts by mass of water to a stirrer, heat to 30°C, stir evenly, then add humic acid and dipotassium hydrogen phosphate, raise the temperature to 80°C and stir to react, and obtain the urea-humic acid-dipotassium hydrogen phosphate complex. The weight ratio of humic acid to urea is 1:6; the weight ratio of dipotassium hydrogen phosphate to urea is 1:8.

[0035] Step (4): Spray 1L of urea-humic acid-dipotassium hydrogen phosphate complex onto 4Kg of amino acid composite hydroxyapatite particles, stir evenly, and dry at 50℃ to obtain ecological fertilizer.

[0036] Comparative Example 1:

[0037] Step (1): Centrifuge and filter the glutamic acid fermentation waste liquid, collect the filtrate, dry and grind the filtrate to obtain microbial protein.

[0038] Step (2): Prepare a 0.05 mol / L zinc silicate aqueous solution, add the bacterial protein prepared in step (1) to it, the ratio of bacterial protein to zinc silicate aqueous solution is 50 g / L; add citric acid, adjust the pH value to 6.0, stir and react for 1 h, add hydroxyapatite with 3 times the mass of the complex, supplement citric acid, continue to adjust the pH value to 6.0, continue to stir and react for 1 h, then centrifuge and filter to obtain amino acid composite hydroxyapatite particles.

[0039] Step (3): Add urea, humic acid, and dipotassium hydrogen phosphate to prepare a urea-humic acid-dipotassium hydrogen phosphate complex. The specific preparation steps are as follows: add 1 part by mass of urea and 2 parts by mass of water to a stirrer, heat to 30°C, stir evenly, then add humic acid and dipotassium hydrogen phosphate, raise the temperature to 80°C and stir to react, and obtain the urea-humic acid-dipotassium hydrogen phosphate complex. The weight ratio of humic acid to urea is 1:6; the weight ratio of dipotassium hydrogen phosphate to urea is 1:8.

[0040] Step (4): Spray 1L of urea-humic acid-dipotassium hydrogen phosphate complex onto 4Kg of amino acid composite hydroxyapatite particles, stir evenly, and dry at 40℃ to obtain ecological fertilizer.

[0041] Comparative Example 2:

[0042] Step (1): Add zinc polysilicate to the glutamic acid fermentation waste liquid, mix for 2 hours, centrifuge and filter, collect the filtrate, dry and grind the filtrate to obtain the microbial protein-zinc polysilicate complex; 2g of zinc polysilicate is added to each 1L of fermentation waste liquid;

[0043] Step (2): Prepare a 0.05 mol / L zinc silicate aqueous solution, add the bacterial protein-polyzinc silicate complex prepared in step (1) to it, the ratio of the amount of complex added to the zinc silicate aqueous solution is 50 g / L; add citric acid, adjust the pH value to 6.0, stir and react for 1 h, add hydroxyapatite with a mass of 3 times that of the complex, continue stirring and react for 1 h, and then centrifuge and filter to obtain amino acid composite hydroxyapatite particles.

[0044] Step (3): Add urea, humic acid, and potassium dihydrogen phosphate to prepare a urea-humic acid complex. The specific preparation steps are as follows: add 1 part by mass of urea and 2 parts by mass of water to a stirrer, heat to 30°C, stir evenly, then add humic acid and potassium dihydrogen phosphate, raise the temperature to 80°C and stir to react, and obtain a urea-humic acid-potassium dihydrogen phosphate complex. The weight ratio of humic acid to urea is 1:6; the weight ratio of potassium dihydrogen phosphate to urea is 1:8.

[0045] Step (4): Spray 1L of urea-humic acid-potassium dihydrogen phosphate complex onto 4Kg of amino acid composite hydroxyapatite granules, stir evenly, and dry at 40℃ to obtain ecological fertilizer.

[0046] Release rate determination: The 24-hour, 7-day, 14-day, 28-day, and 56-day release rates of the fertilizer were determined using the intermittent extraction method recommended in the chemical industry standard for the determination of nutrient release rate of slow-release fertilizers (NY / T3040-2016). The release rates of nitrogen and phosphorus were used as the detection indicators and are listed in Tables 1 and 2 respectively.

[0047] Table 1: Nitrogen release rate in examples and comparative examples

[0048] serial number 24h release rate 7-day release rate 14-day release rate 28-day release rate 56-day release rate Example 1 3.71 5.48 15.27 34.52 72.97 Example 2 4.25 5.93 16.81 37.38 78.26 Comparative Example 1 4.78 11.69 26.57 58.14 94.81 Comparative Example 2 3.96 9.82 24.36 49.86 89.27

[0049] Table 2: Phosphorus release rate in examples and comparative examples

[0050] serial number 24h release rate 7-day release rate 14-day release rate 28-day release rate 56-day release rate Example 1 6.57 13.24 25.71 42.56 60.95 Example 2 6.29 13.59 26.15 44.19 59.64 Comparative Example 1 6.18 12.95 25.90 43.07 58.71 Comparative Example 2 7.94 17.83 34.15 52.74 69.53

[0051] Comparing the nitrogen release rates of the examples and Comparative Example 1 in Table 1, it is evident that adding zinc polysilicate to the fermentation waste liquid can effectively improve the extraction efficiency of bacterial protein and achieve a good sustained-release effect. Comparing the nitrogen release rates of the examples and Comparative Example 2 in Table 1, it is evident that treating hydroxyapatite with citric acid allows amino acids to better bind with hydroxyapatite, thereby achieving a good sustained-release effect of nitrogen.

[0052] As can be seen from the comparison of phosphorus release rates between the examples in Table 2 and Comparative Example 2, citric acid treatment of hydroxyapatite allows amino acids to bind better with hydroxyapatite, thus resulting in a better sustained-release effect of phosphorus in hydroxyapatite. At the same time, dipotassium hydrogen phosphate has a better complexation effect with urea than potassium dihydrogen phosphate with urea, thus resulting in a good sustained-release effect of phosphorus in dipotassium hydrogen phosphate.

[0053] The compound fertilizer performance test of this invention takes Chinese cabbage as an example. Four test cases (1)-(4) were set up, with 10 pots in each group. The design principles are as follows: the soil is all local brown soil; the following fertilizers are applied as base fertilizer before planting Chinese cabbage, and all 40 pots of Chinese cabbage are randomly arranged.

[0054] (1) Ecological fertilizer prepared in Example 1: 20g per pot;

[0055] (2) Ecological fertilizer prepared in Comparative Example 1: Apply 20g per pot;

[0056] (3) Ecological fertilizer prepared in Comparative Example 2: Apply 20g per pot;

[0057] (4) Control group: No fertilizer was applied.

[0058] The relevant results were measured 90 days after planting, and the average of each group was taken, as shown in Table 3.

[0059] Table 3: Test Case Results

[0060] Test case Ball height / cm Ball weight / KG Number of bulbous leaves / pieces Net yield / % (1) 48.9 4.71 57.3 86.5 (2) 44.2 4.34 54.2 81.4 (3) 42.7 4.29 51.9 80.7 (4) 40.3 3.68 44.8 73.6

[0061] As can be seen from Table 3, the head height, head weight, number of leaves and net feed rate of the Chinese cabbage treated with the ecological fertilizer prepared in the embodiments of the present invention are significantly improved compared with the Chinese cabbage treated with compound fertilizer in Comparative Examples 1-2. This is mainly due to the significant slow-release effect of the ecological fertilizer of the present invention on important elements such as nitrogen and phosphorus, which has a significant promoting effect on the growth of Chinese cabbage.

[0062] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A method for preparing a glutamic acid microbial protein eco-fertilizer, characterized in that, The preparation steps include the following: Step (1): Add zinc polysilicate to the glutamic acid fermentation waste liquid, mix for 1-2 hours, centrifuge and filter, collect the filtrate, dry and grind the filtrate to obtain the microbial protein-zinc polysilicate complex, wherein the ratio of the amount of zinc polysilicate added to the waste liquid is 1.5-3g / 1L; Step (2): Prepare a zinc silicate aqueous solution and add the bacterial protein-polyzinc silicate complex prepared in step (1) to it; add citric acid, adjust the pH value to 6.0-7.0, stir and react for 1-2 hours, add hydroxyapatite, and at the same time supplement citric acid, continue to adjust the pH value to 6.0-7.0, continue to stir and react for 1-2 hours, and then centrifuge and filter to obtain amino acid composite hydroxyapatite particles; Step (3): Preparation of urea-humic acid-dipotassium hydrogen phosphate complex; Step (4): Spray the urea-humic acid-dipotassium hydrogen phosphate complex onto the amino acid composite hydroxyapatite particles, stir evenly, and dry at 40-60℃ to obtain the ecological fertilizer.

2. The preparation method according to claim 1, characterized in that, The concentration of the zinc silicate aqueous solution prepared in step (2) is 0.03-0.1 mol / L, and the ratio of the amount of complex added to the zinc silicate aqueous solution is 30-100 g / L.

3. The preparation method according to claim 1, characterized in that, In step (2), the amount of hydroxyapatite added is 2-4 times that of the complex.

4. The preparation method according to claim 1, characterized in that, The specific preparation steps of the urea-humic acid-dipotassium hydrogen phosphate complex in step (3) are as follows: add urea and water to a stirrer in a weight ratio of 1:(2-3), heat to 30-35℃, stir evenly, then add humic acid and dipotassium hydrogen phosphate, raise the temperature to 70-90℃ and stir to react, and obtain the urea-humic acid-dipotassium hydrogen phosphate complex.

5. The preparation method according to claim 4, characterized in that, The weight ratio of humic acid to urea is 1:(5-7); the weight ratio of dipotassium hydrogen phosphate to urea is 1:(6-10).

6. The preparation method according to claim 1, characterized in that, In step (4), the mass ratio of urea-humic acid-potassium dihydrogen phosphate complex and amino acid chelate particles is 1L:(3-5)kg.