Low-cost phosphorus-solubilizing bacteria embedding material and preparation method thereof
By using clay, sawdust, wheat bran, fermentation residue and other raw materials with polyvinyl alcohol crosslinking agents, the problems of high cost and insufficient stability in the existing technology are solved, and efficient and low-cost phosphorus removal effect and stability improvement are achieved.
Patent Information
- Application Number
- CN202510636623.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-17
- Publication Date
- 2025-08-08
AI Technical Summary
The existing phosphorus-removing bacterial embedding materials are costly, complex in preparation, and insufficient stability of the carrier material, which affects the phosphorus-removing effect and is difficult to promote and apply on a large scale.
Clay, sawdust, wheat bran, fermentation residues, polyvinyl alcohol and crosslinking agents are used as the main raw materials, and low-cost phosphorus-removing bacterial embedding materials are prepared through pre-crosslinking and pH control to achieve uniform embedding and stability of phosphorus-removing bacteria.
It significantly reduces production costs, improves the mechanical strength and phosphorus decomposition efficiency of the material, is suitable for large-scale applications, and has a high survival rate of phosphorus decomposition bacteria in embedded materials, adapting to a variety of soil environments.
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Figure CN120442613A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of embedding material preparation, in particular to a low-cost phosphate-solubilizing bacteria embedding material and a preparation method thereof. Background Art
[0002] With the continuous deepening of agricultural production, phosphorus, as a nutrient element necessary for plant growth, occupies an important position in fertilizer application; however, large amounts of chemical phosphorus fertilizers applied are not fully absorbed and utilized by crops, and some phosphorus elements are easily solidified in the soil or enter water bodies with surface runoff, causing ecological and environmental pressure and resource waste; in addition, the effective phosphorus content in the soil that can be directly absorbed and utilized by plants is often limited, which makes it difficult to meet the continuous demand for phosphorus from crops, resulting in decreased fertilization efficiency and increased production costs; to overcome these defects, suitable carrier materials are needed to encapsulate and fix phosphate-solubilizing bacteria, thereby improving the stability of the bacteria and their phosphorus removal performance.
[0003] Existing materials for encapsulating phosphate-solubilizing bacteria mostly use sodium alginate, chitosan, or other polymer materials. These materials are expensive, have limited sources, and have a complex preparation process, making them unsuitable for large-scale promotion and application. In addition, some carrier materials lack mechanical strength in actual applications, are prone to disintegration and bacterial loss, seriously affecting the phosphate-solubilizing effect. To address the problems of high material cost, complex preparation, and insufficient stability of carrier materials in the existing technology, there is an urgent need to develop a low-cost phosphate-solubilizing bacteria encapsulation material prepared from economically available raw materials and a preparation method thereof. Summary of the Invention
[0004] Based on the above objectives, the present invention provides a low-cost phosphate-solubilizing bacteria embedding material and a preparation method thereof.
[0005] A low-cost phosphate-solubilizing bacteria embedding material comprises clay, sawdust, wheat bran, fermentation residue, polyvinyl alcohol, phosphate-solubilizing bacteria, a cross-linking agent and water; wherein the mass percentage of each component is: Clay accounts for 20% to 40%; Sawdust accounts for 5% to 20%; Wheat bran accounts for 5% to 15%; Fermentation residue accounts for 8% to 15%; Polyvinyl alcohol accounts for 3% to 10%; Phosphate-solubilizing bacteria account for 1% to 5%; The cross-linking agent accounts for 0.5% to 2%; The balance is water.
[0006] Optionally, the clay is bentonite, montmorillonite or kaolin; the fermentation residue is beer yeast residue, MSG fermentation residue or lactic acid fermentation residue; the sawdust is selected from rice husk or straw; and the phosphate-solubilizing bacteria is selected from Bacillus pasteurianus, Brevibacterium or Pseudomonas.
[0007] A method for preparing a low-cost phosphate-solubilizing bacteria embedding material comprises the following steps: The following steps are involved: S1, raw material pretreatment: drying and crushing the clay, sawdust and wheat bran respectively, and dehydrating the fermentation residue, so that the raw materials are dry and loose for use; S2, fermentation residue activation: the pretreated fermentation residue is placed at a predetermined temperature for activation to initially release its internal components; S3, pre-crosslinking of carrier: dissolving polyvinyl alcohol in water, adding a crosslinking agent, and reacting under predetermined temperature and stirring conditions for pre-crosslinking to obtain a preliminary crosslinked carrier solution; S4, homogenous mixing: the clay, sawdust and wheat bran treated in S1 are sequentially added to the preliminary cross-linked carrier solution obtained in S3, and then the fermentation residue activated in S2 is slowly added and stirred evenly to prepare a multi-component mixed slurry; S5, pH control: adjusting the pH of the mixed slurry obtained in S4 to achieve a condition suitable for the growth of phosphate-solubilizing bacteria; S6, inoculating phosphate-solubilizing bacteria: After the mixed slurry conditions are stable, inoculate the prepared phosphate-solubilizing bacteria and fully stir and disperse them so that the phosphate-solubilizing bacteria are evenly embedded in the mixed slurry system; S7, molding and curing: the phosphate-solubilizing bacteria embedded mixed slurry obtained in S6 is molded, and the cross-linking reaction and curing are completed under predetermined conditions to obtain a molded low-cost phosphate-solubilizing bacteria embedded material. Optionally, the S1 specifically includes: S11, drying and crushing the clay: placing the clay in a drying oven at 80°C to 100°C for 2 to 4 hours, naturally cooling it to room temperature, and then crushing it into a particle size of 100 mesh to 200 mesh using a crusher for later use; S12, sawdust drying and crushing: spreading the sawdust in a drying device, drying it at 70°C to 90°C for 1 hour to 3 hours, cooling it naturally to room temperature, and then crushing it to a particle size of 100 mesh to 150 mesh for later use; S13, drying and crushing the wheat bran: placing the wheat bran in a drying device, drying it at 60° C. to 80° C. for 1 to 2 hours, cooling it, and then crushing it into a particle size of 80 mesh to 150 mesh using a grinder, and setting it aside; S14, fermentation residue dehydration treatment: the fermentation residue is dehydrated by a plate and frame filter press until the moisture content reaches 15% to 20%, and then collected for standby use.
[0008] Optionally, the S2 specifically includes: S21, placing the pretreated fermentation residue in a sealed reaction container, with a paving thickness of 2 cm to 5 cm; S22, adjusting the internal temperature of the reaction vessel to 30°C to 40°C, controlling the humidity to 50% to 70%, and allowing the reaction vessel to stand for activation for 1 h to 2 h; S23, after activation is completed, cool naturally to room temperature and set aside.
[0009] Optionally, the S3 specifically includes: S31, adding polyvinyl alcohol to deionized water, with a mass ratio of polyvinyl alcohol to water of 1:10 to 1:15, heating to 70° C. to 90° C. under stirring, maintaining a stirring speed of 100 rpm to 300 rpm, and dissolving for 20 min to 40 min to obtain a polyvinyl alcohol solution; S32, after the polyvinyl alcohol solution is cooled to 40°C to 60°C, a cross-linking agent is slowly added at a rate of 5% to 10% of the mass of the polyvinyl alcohol, with the stirring speed controlled at 100 rpm to 200 rpm, and the reaction is continued for 10 min to 20 min; S33, after the reaction is completed, heating is stopped and the solution is naturally cooled to room temperature to obtain a preliminary cross-linked carrier solution for use.
[0010] Optionally, the S4 specifically includes: S41, placing the preliminary cross-linked carrier solution obtained in S3 into a reaction container and continuously stirring at a stirring speed of 50 rpm to 100 rpm; S42, slowly adding the clay, sawdust, and wheat bran treated in S1 to the preliminary cross-linking carrier solution in sequence, with the interval between adding each material being 2 min to 5 min; S43, continue stirring and mixing, increase the stirring speed to 100 rpm to 200 rpm, and continue stirring for 10 min to 20 min; S44. Slowly and evenly add the fermentation residue activated in S2 to the mixed system in S43 at a rate of 1% to 3% of the total mass of the mixed system per minute. After the addition is completed, continue stirring at 150 rpm to 250 rpm for 15 min to 30 min to obtain a multi-component mixed slurry for use.
[0011] Optionally, the S5 specifically includes: S51, placing the multi-component mixed slurry prepared in S4 into a reaction container, and monitoring the initial pH of the slurry using a pH meter; S52, when the initial pH of the slurry is lower than 6.5, slowly dropwise adding a 3% by mass concentration sodium hydroxide solution to the slurry; when the initial pH of the slurry is higher than 7.5, slowly dropwise adding a 3% by mass concentration dilute hydrochloric acid solution to the slurry; S53, control the droplet acceleration rate to 5 mL / min to 15 mL / min, and continue stirring and mixing at a stirring speed of 100 rpm to 200 rpm; S54, continuously monitor the pH of the slurry until it stabilizes between 6.5 and 7.5, stop adding, and let it stand for later use.
[0012] Optionally, the S6 specifically includes: S61, slowly and evenly adding the pre-cultured phosphate-solubilizing bacterial solution to the mixed slurry after treatment in step S5 at a ratio of 1% to 5% of the mass of the mixed slurry; S62, while adding the bacterial solution, continue stirring at a speed of 80 rpm to 150 rpm. After the bacterial solution is completely added, increase the stirring speed to 150 rpm to 200 rpm and continue stirring for 10 min; S63, stop stirring and let it stand for 15 minutes for later use.
[0013] Optionally, the S7 specifically includes: S71, forming the phosphate-solubilizing bacteria-encapsulated mixed slurry obtained in S6 by extrusion granulation to prepare columnar particles with a diameter of 2 mm to 5 mm; S72, evenly spreading the formed particles in a drying device, and drying at a temperature of 40°C to 50°C for 8 h to 12 h; S73, after drying, the particles are placed at room temperature for a further 12 h to 24 h to complete the cross-linking reaction and solidification, and finally a low-cost phosphate-solubilizing bacteria embedding material is obtained.
[0014] Beneficial effects of the present invention: This invention uses natural and industrial waste materials, such as clay, sawdust, wheat bran, and fermentation residues, as primary raw materials. Polyvinyl alcohol is pre-crosslinked with a crosslinking agent to form a stable carrier, enabling uniform encapsulation of phosphate-depleting bacteria. This material boasts a homogeneous structure, high mechanical strength, a wide range of raw material sources, and a simple process, significantly reducing production costs and facilitating large-scale application. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only for the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.
[0016] Figure 1 This is a schematic diagram of the components of the phosphate-solubilizing bacteria embedding material according to an embodiment of the present invention; Figure 2 Schematic diagram of the preparation method of the phosphate-solubilizing bacteria embedding material according to an embodiment of the present invention. DETAILED DESCRIPTION
[0017] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments. It is also noted that, to provide a more detailed description, the following embodiments are best and preferred embodiments, and those skilled in the art may employ alternative methods for implementing certain known technologies. Furthermore, the accompanying drawings are intended only to provide a more detailed description of the embodiments and are not intended to limit the present invention.
[0018] It should be noted that references in the specification to "one embodiment," "an embodiment," "exemplary embodiments," "some embodiments," etc. indicate that the described embodiments may include specific features, structures, or characteristics, but not necessarily every embodiment will include such specific features, structures, or characteristics. Furthermore, when specific features, structures, or characteristics are described in conjunction with an embodiment, it is within the knowledge of persons skilled in the relevant art to implement such features, structures, or characteristics in conjunction with other embodiments (whether or not explicitly described).
[0019] In general, terms can be understood, at least in part, from their use in context. For example, depending at least in part on the context, the term "one or more" as used herein can be used to describe any feature, structure, or characteristic in the singular sense, or can be used to describe a combination of features, structures, or characteristics in the plural sense. Additionally, the term "based on" can be understood as not necessarily intended to convey an exclusive set of factors, but can instead, depending at least in part on the context, allow for the presence of other factors that are not necessarily explicitly described.
[0020] Example 1 like Figure 1 As shown, a low-cost phosphate-solubilizing bacteria embedding material includes clay, sawdust, wheat bran, fermentation residue, polyvinyl alcohol, phosphate-solubilizing bacteria, a cross-linking agent and water; wherein the mass percentage of each component is: Clay accounts for 30%; Sawdust accounts for 10%; Wheat bran accounts for 10%; Fermentation residue accounts for 10%; Polyvinyl alcohol accounts for 5%; Phosphate-solubilizing bacteria accounted for 3%; The cross-linking agent accounts for 1%; The balance is water.
[0021] The clay is bentonite; the fermentation residue is brewer's yeast residue; the sawdust is selected from rice husk; and the phosphate-solubilizing bacteria is selected from Bacillus pasteurianus.
[0022] like Figure 2 As shown, a method for preparing a low-cost phosphate-solubilizing bacteria embedding material comprises the following steps: S1, raw material pretreatment: drying and crushing the clay, sawdust and wheat bran respectively, and dehydrating the fermentation residue, so that the raw materials are dry and loose for use; S2, fermentation residue activation: The pre-treated fermentation residue is placed at a predetermined temperature for activation to initially release its internal components, making it easier for subsequent mixing; S3, pre-crosslinking of carrier: dissolving polyvinyl alcohol in water, adding a crosslinking agent, and reacting under predetermined temperature and stirring conditions for pre-crosslinking to obtain a preliminary crosslinked carrier solution; S4, homogenous mixing: the clay, sawdust and wheat bran treated in S1 are sequentially added to the preliminary cross-linked carrier solution obtained in S3, and then the fermentation residue activated in S2 is slowly added and stirred evenly to prepare a multi-component mixed slurry; S5, pH control: adjusting the pH of the mixed slurry obtained in S4 to achieve a condition suitable for the growth of phosphate-solubilizing bacteria; S6, inoculating phosphate-solubilizing bacteria: After the mixed slurry conditions are stable, inoculate the prepared phosphate-solubilizing bacteria and fully stir and disperse them so that the phosphate-solubilizing bacteria are evenly embedded in the mixed slurry system; S7, molding and curing: the phosphate-solubilizing bacteria embedded mixed slurry obtained in S6 is molded, and the cross-linking reaction and curing are completed under predetermined conditions to obtain a molded low-cost phosphate-solubilizing bacteria embedded material. S1 raw material pretreatment specifically includes: S11, drying and crushing the clay: placing the clay in a drying oven at 90°C for 3 h, naturally cooling it to room temperature, and then crushing it to a particle size of 150 mesh using a grinder for later use; S12, sawdust drying and crushing: spreading the sawdust in a drying device, drying it at 80°C for 2 hours, cooling it naturally to room temperature, and then crushing it to a particle size of 120 mesh for later use; S13, drying and crushing the wheat bran: placing the wheat bran in a drying device, drying it at 70° C. for 1.5 h, cooling it, and then crushing it into a particle size of 100 mesh using a grinder for later use; S14, fermentation residue dehydration treatment: the fermentation residue is dehydrated through a plate and frame filter press, and is collected after dehydration to a moisture content of 18% for later use; through the above steps S11 to S14, the clay, sawdust, and wheat bran are dried and crushed, and the fermentation residue is dehydrated pretreatment is achieved, meeting the raw material requirements for the subsequent preparation of low-cost phosphate-solubilizing bacteria embedding materials.
[0023] S2 fermentation residue activation specifically includes: S21, placing the pretreated fermentation residue in a sealed reaction vessel with a paving thickness of 3 cm; S22, adjusting the internal temperature of the reaction vessel to 35°C and the humidity to 60%, and allowing the reaction vessel to stand for activation for 1.5 h; S23, after activation is completed, cool naturally to room temperature and set aside.
[0024] S3 carrier pre-crosslinking specifically includes: S31, adding polyvinyl alcohol to deionized water in a mass ratio of polyvinyl alcohol to water of 1:12, heating to 80° C. with stirring, maintaining a stirring speed of 200 rpm, and dissolving for 30 min to obtain a polyvinyl alcohol solution; S32, after the polyvinyl alcohol solution is cooled to 50°C, a cross-linking agent is slowly added at a rate of 8% by mass of the polyvinyl alcohol, with the stirring speed controlled at 150 rpm, and the reaction is continued for 15 min; S33, after the reaction is completed, heating is stopped and the solution is naturally cooled to room temperature to obtain a preliminary cross-linked carrier solution for use.
[0025] S4 homogeneous mixing specifically includes: S41, placing the preliminary cross-linked carrier solution obtained in S3 into a reaction vessel and continuously stirring at a stirring speed of 80 rpm; S42, slowly adding the clay, sawdust, and wheat bran treated in S1 to the preliminary cross-linking carrier solution in sequence, with an interval of 3 minutes between additions of each material; S43, continue stirring and mixing, increase the stirring speed to 150 rpm, and continue stirring for 15 min; S44. Slowly and evenly add the fermentation residue activated in S2 to the mixed system in S43 at a rate of 2% of the total mass of the mixed system per minute. After the addition is completed, continue stirring at 200 rpm for 20 minutes to obtain a multi-component mixed slurry for use.
[0026] S5 pH control specifically includes: S51, placing the multi-component mixed slurry prepared in S4 into a reaction container, and monitoring the initial pH of the slurry using a pH meter; S52, when the initial pH of the slurry is lower than 6.5, slowly dropwise adding a 3% by mass concentration sodium hydroxide solution to the slurry; when the initial pH of the slurry is higher than 7.5, slowly dropwise adding a 3% by mass concentration dilute hydrochloric acid solution to the slurry; S53, control the droplet acceleration rate to 10 mL / min and continuously stir and mix at a stirring speed of 150 rpm; S54, continuously monitor the pH of the slurry until it stabilizes between 6.5 and 7.5, stop adding, and let it stand for later use.
[0027] S6 phosphate-solubilizing bacteria inoculation specifically includes: S61, slowly and evenly adding the pre-cultured phosphate-solubilizing bacterial solution to the mixed slurry after treatment in step S5 at a ratio of 2% of the mass of the mixed slurry; S62, while adding the bacterial solution, stirring was continued at a speed of 100 rpm. After the bacterial solution was completely added, the stirring speed was increased to 180 rpm and stirring was continued for 10 min; S63, stop stirring and let it stand for 15 minutes for later use.
[0028] S7 molding and curing specifically includes: S71, forming the phosphate-solubilizing bacteria-encapsulated mixed slurry obtained in S6 by extrusion granulation to prepare columnar particles with a diameter of 3 mm; S72, evenly spread the formed particles in a drying device and dry them at 45°C for 10 h; S73, after drying, the particles are placed at room temperature for another 18 h to complete the cross-linking reaction and solidification, and finally a low-cost phosphate-solubilizing bacteria embedding material is obtained.
[0029] Example 2 Formula and proportion Clay (montmorillonite) 20%; sawdust (from crushed straw) 5%; wheat bran 5%; fermentation residue (from MSG fermentation residue) 8%; polyvinyl alcohol 3%; phosphate-solubilizing bacteria (Breibacterium) 1%; cross-linking agent 0.5%; the balance is water.
[0030] Preparation steps S1: Place clay in a drying oven, dry at 80°C for 2 hours, and then naturally cool to room temperature. Then, grind it in a grinder and sieve it to a particle size of about 100 mesh for later use. Sawdust is pre-crushed and spread in a drying device, dried at 70°C for 1 hour, cooled to room temperature, and then grind it to a particle size of about 100 mesh for later use. Wheat bran is dried at 60°C for 1.5 hours, cooled, and grind it to about 80 mesh for later use. Fermentation residue is dehydrated to a moisture content of about 15% using a plate and frame filter press and then collected for later use. S2: Spread the dehydrated fermentation residue in a sealed reaction vessel to a thickness of about 2 cm. Adjust the internal temperature of the container to 30°C and the humidity to about 50%, and let it stand for activation for 1 hour. After activation, naturally cool it to room temperature for later use. S3: Add polyvinyl alcohol to deionized water at a mass ratio of 1:10, heat to 70°C and dissolve for 20 minutes while stirring at approximately 100 rpm to obtain a clear polyvinyl alcohol solution; after cooling the solution to approximately 40°C, slowly add a crosslinker solution at a mass ratio of approximately 5% of the polyvinyl alcohol, maintain stirring at approximately 100 rpm, and continue the reaction for 10 minutes; after the reaction is completed, stop heating and allow the solution to cool naturally to room temperature to obtain a preliminary crosslinked carrier solution for use; S4: Place the preliminary cross-linked carrier solution in a reaction vessel and continue stirring at about 50 rpm; slowly add the clay, sawdust, and wheat bran treated by S1 in sequence, with an interval of about 2 minutes between each addition; after all are added, increase the stirring speed to 100 rpm and continue stirring for about 10 minutes; then slowly add the fermentation residue activated by S2 at a rate of 1% / min of the total mass of the mixed system; after all are added, continue stirring at 150 rpm for 15 minutes to obtain a multi-component mixed slurry for use; S5: The mixed slurry is transferred to a reaction vessel. When the initial pH is 7.5 as measured by a pH meter, a 3% dilute hydrochloric acid solution is added dropwise at a rate of about 5 mL / min. During the addition, the stirring speed is maintained at about 100 rpm, and the pH is monitored in real time. When the pH of the slurry stabilizes between 6.5 and 7.5, the addition is stopped and the slurry is allowed to stand for further use. S6: Slowly add the pre-cultured phosphate-solubilizing bacteria solution to the pH-adjusted slurry at a rate of 1% of the mixed slurry mass, stirring at a speed of about 80 rpm. After the bacteria solution is added, increase the stirring speed to 150 rpm and continue stirring for 10 minutes. After stopping stirring, let it stand for 15 minutes for use. S7: The phosphate-solubilizing bacteria-encapsulated mixed slurry obtained after inoculation is made into columnar particles with a diameter of about 2 mm by extrusion granulation; the particles are dried at 40°C for 8 h; after drying, they are allowed to stand at room temperature for 12 h to complete cross-linking and curing, thereby obtaining a low-cost phosphate-solubilizing bacteria-encapsulating material.
[0031] Example 3 Formula and proportion Clay (kaolin) 40%; sawdust (crushed rice husk) 20%; wheat bran 15%; fermentation residue (lactic acid fermentation residue) 15%; polyvinyl alcohol 10%; phosphate-solubilizing bacteria (Pseudomonas) 5%; cross-linking agent 2%; the balance is water.
[0032] Preparation steps S1: Place clay in a drying oven, dry at 100°C for 4 hours, and then naturally cool to room temperature. Then, grind it in a grinder and sieve it to a particle size of about 200 mesh for later use; pre-crush sawdust and spread it in a drying device, dry it at 90°C for 3 hours, cool it to room temperature, and then grind it to a particle size of about 150 mesh for later use; dry wheat bran at 80°C for 2 hours, cool it, and grind it to a particle size of about 150 mesh for later use; dehydrate the fermentation residue in a plate and frame filter press to a moisture content of about 20%, and then collect it for later use; S2: Spread the dehydrated fermentation residue in a sealed reaction vessel to a thickness of about 5 cm. Adjust the internal temperature of the container to 40°C and the humidity to about 70%, and let it stand for activation for 2 hours. After activation, naturally cool it to room temperature for later use. S3: Add polyvinyl alcohol to deionized water at a mass ratio of 1:15, heat to 90°C with stirring at approximately 300 rpm, and dissolve for 40 minutes to obtain a clear polyvinyl alcohol solution; after cooling the solution to approximately 60°C, slowly add a crosslinker solution at a mass ratio of approximately 10% of the polyvinyl alcohol, maintain stirring at approximately 200 rpm, and continue the reaction for 20 minutes; after the reaction is completed, stop heating and allow the solution to cool naturally to room temperature to obtain a preliminary crosslinked carrier solution for use; S4: Place the preliminary cross-linked carrier solution in a reaction vessel and continue stirring at about 100 rpm; slowly add the clay, sawdust, and wheat bran treated by S1 in sequence, with an interval of about 5 minutes between each addition; after all are added, increase the stirring speed to 200 rpm and continue stirring for about 20 minutes; then slowly add the fermentation residue activated by S2 at a rate of 3% / min of the total mass of the mixed system; after all are added, continue stirring at 250 rpm for 30 minutes to obtain a multi-component mixed slurry for use; S5: The mixed slurry is transferred to a reaction vessel. When the initial pH is 7.5 as measured by a pH meter, a 3% dilute hydrochloric acid solution is added dropwise at a rate of about 15 mL / min. During the addition, the stirring speed is maintained at about 200 rpm, and the pH is monitored in real time. When the pH of the slurry stabilizes between 6.5 and 7.5, the addition is stopped and the slurry is allowed to stand for further use. S6: Slowly add the pre-cultured phosphate-solubilizing bacteria solution to the pH-adjusted slurry at a rate of 5% of the mixed slurry mass, stirring at a speed of about 150 rpm. After the bacteria solution is added, increase the stirring speed to 200 rpm and continue stirring for 10 minutes. After stopping stirring, let it stand for 15 minutes for later use. S7: The phosphate-solubilizing bacteria-encapsulated mixed slurry obtained after inoculation is extruded and granulated into columnar particles with a diameter of about 5 mm; the particles are dried at 50°C for 12 hours; after drying, they are allowed to stand at room temperature for 24 hours to complete cross-linking and curing, thereby obtaining a low-cost phosphate-solubilizing bacteria-encapsulated material.
[0033] Comparative Example 1 Components and proportions Sodium alginate 3%; phosphate-solubilizing bacteria solution 2%; CaCl2 solution 2%; the balance is water; Preparation steps Step 1: Dissolve 3 g of sodium alginate in 100 ml of deionized water and stir at 60°C for 20 minutes until completely dissolved. After the solution cools to room temperature, add the phosphate-solubilizing bacteria solution and stir thoroughly to evenly disperse the bacteria. Step 2: Use a syringe to add the mixed embedding solution to the pre-prepared CaCl2 cross-linking solution at a rate of about 2 ml / min. During the addition process, each drop of liquid can quickly react with calcium ions to form embedding particles with a diameter of about 5 mm.
[0034] Table 1 Comparison of properties of finished embedding materials As can be seen from Table 1 above, the phosphorus release efficiency of Example 1 can reach 91%, which is significantly higher than 65% of Comparative Example 1. At the same time, the number of viable bacteria is also maintained at a high level (8.5×10 8 The compressive strength (13.0 N / cm²) and water stability (95%) of the particles of Example 1 were superior to those of the other Examples and Comparative Examples, making the material more stable and less prone to breakage and disintegration during transportation, spreading, and environmental immersion. Example 1 was able to maintain good phosphate solubilization within a pH range of 5.0 to 9.0, and had a sustained phosphate release period of up to 30 days, indicating that it could maintain a long phosphate release period under a wider range of soil pH conditions. The cost of Example 1 was approximately 2.2 yuan / kg, slightly higher than that of Comparative Example 1 (1.8 yuan / kg), but considering the improvements in other performance indicators, the cost-effectiveness was more outstanding. In summary, Example 1 demonstrated excellent comprehensive performance in multiple aspects, including phosphate release efficiency, viable bacterial survival rate, material stability, and applicability. Although its cost was slightly higher than that of Comparative Example 1, Example 1 better met the requirements for application scenarios requiring efficient phosphate release and tolerance to a wider range of environmental conditions, and thus can be regarded as the best embodiment of the present invention.
[0035] Table 2 Comparison of other performance parameters As can be seen from Table 2 above, Example 1 reaches a maximum of 93%, which is significantly higher than the 65% of Comparative Example 1, and can more effectively convert insoluble phosphorus into absorbable and usable effective phosphorus; the particle breakage rate of Example 1 is only 2%, which is much lower than the 12% of Comparative Example 1, indicating that it has good morphological stability during transportation, application and natural environment; under high temperature (40°C) conditions, the bacterial survival rate of Example 1 remains at 85%, while that of Comparative Example 1 is only 40%, indicating that the embedding material of Example 1 is more resistant to high temperature stress; at the same time, the pH fluctuation range of the soil after application is only ±0.3, which is significantly lower than the ±1.2 of Comparative Example 1, which is conducive to the balance and stability of the soil environment; Example 1 scored 2 in the biological toxicity test (the lower the score, the safer), and its affinity with plant roots is as high as 9 (0-10 ), indicating that the material is safe for crops and helps promote the health of the root microenvironment; Example 1 can adapt to 5 different types of soil, has a wider range of applications, and meets the phosphorus release needs in multiple regions and soil conditions; based on various comparative data, Example 1 performs excellently in many aspects such as phosphorus conversion efficiency, environmental adaptability, material stability, and ecological safety, and thus it can be confirmed again that it has the greatest application value among all the test schemes and can be regarded as the best embodiment.
[0036] The present invention encompasses any alternatives, modifications, equivalents, and solutions that fall within the spirit and scope of the present invention. To provide a thorough understanding of the present invention, specific details are described in detail below in connection with the preferred embodiments of the present invention, but those skilled in the art will be able to fully understand the present invention without these detailed descriptions. Furthermore, to avoid unnecessary confusion regarding the essence of the present invention, well-known methods, processes, procedures, components, and circuits have not been described in detail.
[0037] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.
Claims
1. A low-cost phosphate-solubilizing bacteria embedding material, characterized in that: It includes clay, sawdust, wheat bran, fermentation residue, polyvinyl alcohol, phosphate-solubilizing bacteria, cross-linking agent and water; wherein the weight percentage of each component is: Clay accounts for 20% to 40%; Sawdust accounts for 5% to 20%; Wheat bran accounts for 5% to 15%; Fermentation residue accounts for 8% to 15%; Polyvinyl alcohol accounts for 3% to 10%; Phosphate-solubilizing bacteria account for 1% to 5%; The cross-linking agent accounts for 0.5% to 2%; The balance is water.
2. A low-cost phosphate-solubilizing bacteria embedding material according to claim 1, characterized in that The clay is bentonite, montmorillonite or kaolin; the fermentation residue is beer yeast residue, monosodium glutamate fermentation residue or lactic acid fermentation residue; the sawdust is selected from rice husk or straw; and the phosphate-solubilizing bacteria are selected from Bacillus pasteurianus, Brevibacterium or Pseudomonas.
3. The method for preparing a low-cost phosphate-solubilizing bacteria embedding material according to any one of claims 1 to 2, characterized in that: The following steps are involved: S1, raw material pretreatment: drying and crushing the clay, sawdust and wheat bran respectively, and dehydrating the fermentation residue, so that the raw materials are dry and loose for use; S2, fermentation residue activation: the pretreated fermentation residue is placed at a predetermined temperature for activation to initially release its internal components; S3, pre-crosslinking of carrier: dissolving polyvinyl alcohol in water, adding a crosslinking agent, and reacting under predetermined temperature and stirring conditions for pre-crosslinking to obtain a preliminary crosslinked carrier solution; S4, homogenous mixing: the clay, sawdust and wheat bran treated in S1 are sequentially added to the preliminary cross-linked carrier solution obtained in S3, and then the fermentation residue activated in S2 is slowly added and stirred evenly to prepare a multi-component mixed slurry; S5, pH control: adjusting the pH of the mixed slurry obtained in S4 to achieve a condition suitable for the growth of phosphate-solubilizing bacteria; S6, inoculating phosphate-solubilizing bacteria: After the mixed slurry conditions are stable, inoculate the prepared phosphate-solubilizing bacteria and fully stir and disperse them so that the phosphate-solubilizing bacteria are evenly embedded in the mixed slurry system; S7, molding and curing: molding the phosphate-solubilizing bacteria embedding mixed slurry obtained in S6, and completing cross-linking reaction and curing under predetermined conditions to obtain a molded low-cost phosphate-solubilizing bacteria embedding material.
4. The method for preparing a low-cost phosphate-solubilizing bacteria embedding material according to claim 3, wherein: Said S1 specifically includes: S11, drying and crushing the clay: placing the clay in a drying oven at 80°C to 100°C for 2 to 4 hours, naturally cooling it to room temperature, and then crushing it into a particle size of 100 to 200 mesh using a crusher for later use; S12, sawdust drying and crushing: spreading the sawdust in a drying device, drying it at 70°C to 90°C for 1 to 3 hours, cooling it naturally to room temperature, and then crushing it to a particle size of 100 to 150 mesh for later use; S13, drying and crushing the wheat bran: placing the wheat bran in a drying device, drying it at 60° C. to 80° C. for 1 to 2 hours, cooling it, and then crushing it into a particle size of 80 mesh to 150 mesh using a grinder, and setting it aside; S14, fermentation residue dehydration treatment: the fermentation residue is dehydrated by a plate and frame filter press until the moisture content reaches 15% to 20%, and then collected for standby use.
5. The method for preparing a low-cost phosphate-solubilizing bacteria embedding material according to claim 3, wherein: The S2 specifically includes: S21, placing the pretreated fermentation residue in a sealed reaction container, with a paving thickness of 2 cm to 5 cm; S22, adjusting the internal temperature of the reaction vessel to 30°C to 40°C, controlling the humidity to 50% to 70%, and allowing the reaction vessel to stand for activation for 1 h to 2 h; S23, after activation is completed, cool naturally to room temperature and set aside.
6. The method for preparing a low-cost phosphate-solubilizing bacteria embedding material according to claim 3, wherein: The S3 specifically includes: S31, adding polyvinyl alcohol to deionized water, with a mass ratio of polyvinyl alcohol to water of 1:10 to 1:15, heating to 70° C. to 90° C. under stirring, maintaining a stirring speed of 100 rpm to 300 rpm, and dissolving for 20 min to 40 min to obtain a polyvinyl alcohol solution; S32, after the polyvinyl alcohol solution is cooled to 40°C to 60°C, a cross-linking agent is slowly added at a rate of 5% to 10% of the mass of the polyvinyl alcohol, with the stirring speed controlled at 100 rpm to 200 rpm, and the reaction is continued for 10 min to 20 min; S33, after the reaction is completed, heating is stopped and the solution is naturally cooled to room temperature to obtain a preliminary cross-linked carrier solution for use.
7. The method for preparing a low-cost phosphate-solubilizing bacteria embedding material according to claim 3, wherein: The S4 specifically includes: S41, placing the preliminary cross-linked carrier solution obtained in S3 into a reaction vessel and continuously stirring at a stirring speed of 50 rpm to 100 rpm; S42, slowly adding the clay, sawdust, and wheat bran treated in S1 to the preliminary cross-linking carrier solution in sequence, with the interval between adding each material being 2 min to 5 min; S43, continue stirring and mixing, increase the stirring speed to 100 rpm to 200 rpm, and continue stirring for 10 min to 20 min; S44. Slowly and evenly add the fermentation residue activated in S2 to the mixed system in S43 at a rate of 1% to 3% of the total mass of the mixed system per minute. After the addition is completed, continue stirring at 150 rpm to 250 rpm for 15 min to 30 min to obtain a multi-component mixed slurry for use.
8. The method for preparing a low-cost phosphate-solubilizing bacteria embedding material according to claim 3, wherein: The S5 specifically includes: S51, placing the multi-component mixed slurry prepared in S4 into a reaction container, and monitoring the initial pH of the slurry using a pH meter; S52, when the initial pH of the slurry is lower than 6.5, slowly dropwise adding a 3% by mass concentration sodium hydroxide solution to the slurry; when the initial pH of the slurry is higher than 7.5, slowly dropwise adding a 3% by mass concentration dilute hydrochloric acid solution to the slurry; S53, control the droplet acceleration rate to 5 mL / min to 15 mL / min, and continue stirring and mixing at a stirring speed of 100 rpm to 200 rpm; S54, continuously monitor the pH of the slurry until it stabilizes between 6.5 and 7.5, stop adding, and let it stand for later use.
9. The method for preparing a low-cost phosphate-solubilizing bacteria embedding material according to claim 3, wherein: The S6 specifically includes: S61, slowly and evenly adding the pre-cultured phosphate-solubilizing bacterial solution to the mixed slurry after treatment in step S5 at a ratio of 1% to 5% of the mass of the mixed slurry; S62, while adding the bacterial solution, continue stirring at a speed of 80 rpm to 150 rpm. After the bacterial solution is completely added, increase the stirring speed to 150 rpm to 200 rpm and continue stirring for 10 min; S63, stop stirring and let it stand for 15 minutes for later use.
10. The method for preparing a low-cost phosphate-solubilizing bacteria embedding material according to claim 3, characterized in that: The S7 specifically includes: S71, forming the phosphate-solubilizing bacteria-encapsulated mixed slurry obtained in S6 by extrusion granulation to prepare columnar particles with a diameter of 2 mm to 5 mm; S72, evenly spreading the formed particles in a drying device, and drying at a temperature of 40° C. to 50° C. for 8 h to 12 h; S73, after drying, the particles are placed at room temperature for a further 12 h to 24 h to complete the cross-linking reaction and solidification, and finally a low-cost phosphate-solubilizing bacteria embedding material is obtained.