Method for preparing fertilizer by extracting amino acid from alanine fermentation liquor

Abstract

The invention discloses a method for preparing a fertilizer by extracting amino acid from alanine fermentation broth, and relates to the technical field of fertilizer preparation, and the method comprises the steps of pretreatment of the alanine fermentation broth, ion exchange adsorption, elution, concentration and fertilizer blending. Impurities are removed step by step from large particles to small particles, the impurities with different particle sizes are effectively intercepted, a pure alanine fermentation liquor foundation is provided for the subsequent extraction process, and under reasonable temperature and stirring rate control, the filtering efficiency is ensured, the fermentation liquor components are prevented from being changed due to overheating or excessive stirring, and the alanine fermentation liquor extraction efficiency is improved. Through ultrasonic treatment, macromolecular substances in the crude alanine fermentation liquor are dispersed more uniformly, the structure of the crude alanine fermentation liquor is destroyed, the fluidity of the fermentation liquor and the contact area of subsequent ion exchange are enhanced, the ultrasonic frequency, power, temperature and stirring rate are accurately controlled, and the stability and reliability of the ultrasonic treatment effect can be guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of fertilizer preparation, in particular to a method for preparing fertilizer by extracting amino acids from alanine fermentation broth. Background Art

[0002] In the process of the continuous development of modern agriculture, fertilizers play an indispensable role. With the continuous growth of population and the increasing requirements of people for the quality and yield of agricultural products, traditional fertilizers can no longer meet the diversified needs of current agricultural production. High-efficiency, environmentally friendly and multifunctional fertilizers have become the goal pursued in the agricultural field. Amino acid fertilizers, as a new type of fertilizer, have significant advantages and are gradually receiving widespread attention. Alanine is widely used in many fields. Its fermentation production process produces a large amount of fermentation broth, which contains rich amino acid resources. However, the current technology for extracting amino acids from alanine fermentation broth still has many shortcomings. For example, traditional extraction methods are often cumbersome and inefficient. In the pretreatment stage, the filtration link may not be able to effectively remove various impurities, resulting in equipment clogging and product purity problems in the subsequent extraction process. In the activated carbon adsorption process, due to improper control of the adsorption conditions, impurities and pigments cannot be fully adsorbed, and the adsorption loss of amino acids may also be large. Amino acids, as the basic units of protein, play an important role in plant growth. They can be directly absorbed and utilized by plants and participate in various physiological and biochemical processes of plants, such as promoting Photosynthesis, enhancing plant stress resistance, etc., extracting amino acids from alanine fermentation broth to prepare fertilizers can achieve resource reuse and improve resource utilization. Alanine can be produced by fermentation. With the advancement of biotechnology, the alanine fermentation industry continues to develop and the output gradually increases. A large amount of fermentation broth is produced during the fermentation process, which is rich in alanine and other nutrients. However, the current treatment methods for alanine fermentation broth are not perfect enough. Part of the direct discharge not only causes waste of resources, but also puts certain pressure on the environment. Therefore, it is of great significance to explore methods for extracting amino acids from alanine fermentation broth to prepare fertilizers, which can not only solve the problem of fermentation broth treatment, but also develop potential new fertilizer products. To this end, we propose a method for extracting amino acids from alanine fermentation broth to prepare fertilizers. Summary of the invention

[0003] The object of the present invention is to provide a method for preparing fertilizer by extracting amino acids from alanine fermentation broth.

[0004] In order to solve the problems raised in the above background technology, the present invention provides the following technical solutions: a method for extracting amino acids from alanine fermentation broth to prepare fertilizer, comprising pretreatment of alanine fermentation broth, ion exchange adsorption, elution, concentration and fertilizer preparation, wherein the specific operation steps of extracting amino acids from alanine fermentation broth to prepare fertilizer are as follows: Step 1: pretreating the alanine fermentation broth, obtaining a high-purity alanine fermentation broth after three sets of filtration, transferring the high-purity alanine fermentation broth to a reactor equipped with a stirrer and a heating device, and adding activated carbon for adsorption to obtain a crude alanine fermentation broth; Step 2, subjecting the adsorbed crude alanine fermentation broth to ultrasonic treatment and then subjecting it to ion exchange adsorption, controlling the flow rate and temperature of the crude alanine fermentation broth to obtain an exchange column adsorbed with amino acid ions; Step 3, immersing the exchange column adsorbed with amino acid ions in an eluent to elute the amino acids from the ion exchange resin, transferring the collected eluent to a concentrator, and concentrating it under reduced pressure at low temperature to obtain a concentrated amino acid solution; Step 4: Transfer the concentrated amino acid solution to a mixing container with a stirring device, add nitrogen, phosphorus, potassium and trace elements, mix and prepare according to the proportion, and add humic acid and alginic acid to mix well to make an amino acid fertilizer; Step 5: Use nanoparticles to encapsulate the prepared amino acid fertilizer, and transfer the encapsulated fertilizer product to a spray drying device for drying. When the humidity reaches a stable value and the water content of the fertilizer meets the standard, the drying is stopped, and the amino acid fertilizer product is collected.

[0005] As a further scheme of the present invention: in the step 1, the alanine fermentation broth is passed through a stainless steel filter screen filter device with a pore size of 100 um, and the alanine fermentation broth is continuously stirred to make it pass through the filter screen evenly, and the larger particle impurities and incompletely fermented solid residues are initially filtered out, the stirring temperature is 25° C.-30° C., and the stirring rate is 50 r / min-80 r / min. The initially filtered alanine fermentation broth is passed through a polypropylene filter membrane filter device with a pore size of 50 um, and pressurized to make the alanine fermentation broth stably pass through the polypropylene filter membrane, and the smaller particle impurities are removed by fine filtration, and the flow rate is controlled between 50 L / h-60 L / h. The finely filtered alanine fermentation broth is passed through a polytetrafluoroethylene filter membrane with a pore size of 10 um, and the pressure is controlled between 0.1 MPa-0.2 MPa. After deep filtration, a high-purity alanine fermentation broth is obtained.

[0006] As a further scheme of the present invention: in the step 1, the high-purity alanine fermentation broth is added to a reactor equipped with a stirrer and a heating device, 4%-6% of the total mass of the high-purity alanine fermentation broth is added with granular activated carbon, the stirrer is turned on, the stirring rate is controlled to be 60r / min-90r / min, the activated carbon and the fermentation broth are fully mixed, and the heating device is turned on at the same time, the temperature in the reactor is increased to 38°C-45°C, and an adsorption reaction is carried out. After adsorption for 2h-6h, the stirring is stopped, the activated carbon is naturally precipitated in the reactor for 45min, the fermentation broth on the upper layer is slowly drawn out, and it is passed through a fine filter membrane with a pore size of 5um to obtain a crude alanine fermentation broth.

[0007] As a further scheme of the present invention: in the step 2, the crude alanine fermentation broth is transferred to an ultrasonic treatment container, the ultrasonic frequency is adjusted to 35kHz-45kHz, and the power is 120W-150W. Within this range, the ultrasonic treatment is continued for 40min-60min. During the ultrasonic process, the temperature of the fermentation broth is maintained at 30°C-35°C, and the crude alanine fermentation broth is continuously stirred, and the stirring rate is controlled to be 40r / min-60r / min.

[0008] As a further scheme of the present invention: in the step 2, a strong acid cation exchange resin column is selected, and the strong acid cation exchange resin column is rinsed with deionized water to remove impurities and residual chemical substances therein, and the resin is soaked with a hydrochloric acid solution with a concentration of 2 mol / L-3 mol / L, and the crude alanine fermentation broth after ultrasonic treatment is passed through the strong acid cation exchange resin column at a flow rate of 4 BV / h-6 BV / h, while maintaining the temperature between 28°C and 32°C. During the adsorption process, it is necessary to detect the content of amino acids in the effluent, and when the concentration of amino acids in the distillate reaches a certain value, the feeding is stopped.

[0009] As a further scheme of the present invention: in the step three, the exchange column adsorbed with amino acid ions is immersed in a container filled with eluent, and a hydrochloric acid solution with a concentration of 2.5 mol / L-3.0 mol / L is selected as the eluent, ensuring that the eluent completely immerses the cation exchange resin column adsorbed with amino acid ions, and the column is immersed for 30 min-45 min, and is continuously stirred, and the stirring rate is controlled to be 20 r / min-40 r / min. After the immersion is completed, the outlet valve of the elution container is opened, the eluent is slowly discharged, and the eluent containing amino acids is collected.

[0010] As a further scheme of the present invention: in the step three, the collected eluate is transferred to a concentrator, concentrated under reduced pressure at low temperature, the temperature of the concentrator is set to 45°C-50°C, and the pressure is controlled between -0.08MPa--0.10MPa. Under this condition, the water in the eluate is slowly evaporated, and the amino acid solution is slowly concentrated. During the evaporation and concentration process, the volume change of the amino acid solution is observed, and the concentration operation is stopped when the volume of the amino acid solution is reduced to 1 / 4-1 / 3 of the original amino acid solution.

[0011] As a further scheme of the present invention: in the step 4, according to the needs of different crops and soil conditions, the total addition amount of nitrogen, phosphorus, potassium and trace elements is determined to be 5%-8% of the total amount of the concentrated amino acid solution, and the concentrated amino acid solution is transferred to a mixing container with a stirring device. Urea and ammonium nitrate are selected as nitrogen sources, potassium dihydrogen phosphate and superphosphate are selected as phosphorus sources, and potassium sulfate and potassium chloride are selected as potassium sources. Among them, trace elements include iron, zinc and boron. Humic acid and alginate can be added during the preparation process. The addition amount of humic acid accounts for 5g-10g per kilogram of fertilizer, and the addition amount of alginate accounts for 2g-5g per kilogram of fertilizer.

[0012] As a further scheme of the present invention: in the step 5, nano calcium carbonate is selected as the nano material, the prepared amino acid fertilizer is placed in a stirring container, 3%-5% of the total mass of the fertilizer is slowly added with nano calcium carbonate, and stirred at a stirring rate of 40r / min-60r / min for 20min-30min. During the stirring process, 1%-2% of the total mass of the nano calcium carbonate is added with sodium dodecylbenzene sulfonate. After the stirring is completed, it is ensured that the nano material is evenly coated on the surface of the fertilizer particles, and the coated fertilizer product is transferred to a spray drying device. Using a spray dryer, the inlet temperature is set to 120℃-150℃, and the outlet temperature is set to 70℃-90℃. The fertilizer is sprayed into the dryer to quickly evaporate the water in the fertilizer to form a dry nano particle fertilizer.

[0013] By adopting the above technical solution, compared with the prior art, the beneficial effects of the present invention are: 1. The present invention performs three groups of progressive filtration on the alanine fermentation broth to remove impurities step by step from large particles to small particles, effectively intercepts impurities of different particle sizes, and provides a pure alanine fermentation broth basis for the subsequent extraction process. Under the control of reasonable temperature and stirring rate, the filtration efficiency is guaranteed and the fermentation broth components are prevented from changing due to overheating or excessive stirring. The macromolecular substances in the crude alanine fermentation broth are dispersed more evenly by ultrasonic treatment, and their structure is destroyed, thereby enhancing the fluidity of the fermentation broth and the contact area of ​​the subsequent ion exchange. The ultrasonic frequency, power, temperature and stirring rate are precisely controlled to ensure the stability and reliability of the ultrasonic treatment effect. In the ion exchange adsorption stage, the strongly acidic cation exchange resin column has higher adsorption selectivity and adsorption capacity for amino acid ions after being pretreated by washing with deionized water and soaking in a hydrochloric acid solution. The fermentation broth flow rate and temperature are strictly controlled to ensure the full adsorption of amino acid ions on the resin column, thereby improving the adsorption efficiency. At the same time, the feeding stop timing is accurately grasped by detecting the amino acid content in the effluent, thereby avoiding the waste of resources and ensuring the product quality. 2. The present invention uses nano calcium carbonate to evenly wrap the surface of fertilizer particles to form a stable nano particle structure, which can effectively improve the stability of the fertilizer and extend the shelf life of the fertilizer. At the same time, the finished fertilizer has good slow release performance, which can achieve the slow release of nutrients, reduce nutrient loss, and improve the utilization efficiency of the fertilizer. By selecting nitrogen sources, phosphorus sources and potassium sources, and reasonably matching trace elements such as iron, zinc, and boron, the fertilizer nutrients are more comprehensive and balanced. By adding humic acid and alginic acid, the activity and functionality of the fertilizer are enhanced, the absorption and utilization of nutrients by plants are promoted, and the utilization rate of the fertilizer is improved. At the same time, the soil structure is improved and the soil's ability to retain water and fertilizer is enhanced. The finished fertilizer is dried by using a spray drying operation. During the drying process, the inlet and outlet temperatures are reasonably set, and the effective ingredients and nano structure of the fertilizer are quickly evaporated without destroying the effective ingredients and nano structure of the fertilizer, thereby ensuring the quality of the finished fertilizer and making it easier to store, transport and use. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 The figure is a schematic diagram of a specific process for preparing an amino acid fertilizer in an embodiment of the present invention. DETAILED DESCRIPTION

[0015] The specific embodiments of the present invention are further described below in conjunction with the accompanying drawings. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0016] The present invention discloses a method for preparing fertilizer by extracting amino acids from alanine fermentation broth, which comprises pretreatment of the alanine fermentation broth, ion exchange adsorption, elution, concentration and fertilizer preparation. The specific operation steps of extracting amino acids from the alanine fermentation broth to prepare fertilizer are as follows: Step 1: pretreating the alanine fermentation broth, filtering it through three groups to obtain a high-purity alanine fermentation broth, transferring the high-purity alanine fermentation broth to a reactor equipped with a stirrer and a heating device, and adding activated carbon for adsorption to obtain a crude alanine fermentation broth; Step 2: ultrasonically treat the adsorbed crude alanine fermentation broth and then perform ion exchange adsorption, control the flow rate and temperature of the crude alanine fermentation broth, and prepare an exchange column adsorbed with amino acid ions; Step 3, immersing the exchange column adsorbed with amino acid ions in an eluent to elute the amino acids from the ion exchange resin, transferring the collected eluent to a concentrator, and concentrating it under reduced pressure at low temperature to obtain a concentrated amino acid solution; Step 4: Transfer the concentrated amino acid solution to a mixing container with a stirring device, add nitrogen, phosphorus, potassium and trace elements, mix and prepare according to the proportion, and add humic acid and alginic acid to mix well to make an amino acid fertilizer; Step 5: Use nanoparticles to encapsulate the prepared amino acid fertilizer, and transfer the encapsulated fertilizer product to a spray drying device for drying. When the humidity reaches a stable value and the water content of the fertilizer meets the standard, the drying is stopped, and the amino acid fertilizer product is collected.

[0017] In one embodiment of the present invention: in step 1, the alanine fermentation broth is passed through a stainless steel filter screen filter device with a pore size of 100 um, and the alanine fermentation broth is continuously stirred to make it pass through the filter screen evenly, and the larger particle impurities and incompletely fermented solid residues are initially filtered to be removed, the stirring temperature is 25°C-30°C, the stirring rate is 50r / min-80r / min, the initially filtered alanine fermentation broth is passed through a polypropylene filter membrane filter device with a pore size of 50 um, pressurized to make the alanine fermentation broth stably pass through the polypropylene filter membrane, fine filtration to remove smaller particle impurities, the flow rate is controlled between 50L / h-60L / h, the finely filtered alanine fermentation broth is passed through a polytetrafluoroethylene filter membrane with a pore size of 10 um, the pressure is controlled between 0.1MPa-0.2MPa, and high-purity alanine fermentation broth is obtained after deep filtration.

[0018] In one embodiment of the present invention: in step 1, the high-purity alanine fermentation broth is added to a reactor with a stirrer and a heating device, 4%-6% of the total mass of the high-purity alanine fermentation broth is added with granular activated carbon, the stirrer is turned on, the stirring rate is controlled to be 60r / min-90r / min, the activated carbon and the fermentation broth are fully mixed, and the heating device is turned on at the same time, the temperature in the reactor is increased to 38°C-45°C, and an adsorption reaction is carried out. After adsorption for 2h-6h, the stirring is stopped, and the activated carbon is naturally precipitated in the reactor for 45min, the fermentation broth on the upper layer is slowly drawn out, and it is passed through a fine filter membrane with a pore size of 5um to obtain a crude alanine fermentation broth.

[0019] In one embodiment of the present invention: in step 2, the crude alanine fermentation broth is transferred to an ultrasonic treatment container, the ultrasonic frequency is adjusted to 35kHz-45kHz, and the power is 120W-150W. Within this range, the ultrasonic treatment is continued for 40min-60min. During the ultrasonic process, the temperature of the fermentation broth is maintained at 30°C-35°C, and the crude alanine fermentation broth is continuously stirred, and the stirring rate is controlled to be 40r / min-60r / min.

[0020] In one embodiment of the present invention: in step 2, a strong acid cation exchange resin column is selected, and the strong acid cation exchange resin column is rinsed with deionized water to remove impurities and residual chemical substances therein, and the resin is soaked with a hydrochloric acid solution with a concentration of 2 mol / L-3 mol / L, and the crude alanine fermentation broth after ultrasonic treatment is passed through the strong acid cation exchange resin column at a flow rate of 4 BV / h-6 BV / h, while maintaining the temperature between 28°C and 32°C. During the adsorption process, it is necessary to detect the content of amino acids in the effluent, and when the concentration of amino acids in the distillate reaches a certain value, the feeding is stopped.

[0021] In one embodiment of the present invention: in step three, the exchange column adsorbed with amino acid ions is immersed in a container filled with eluent, and a hydrochloric acid solution with a concentration of 2.5 mol / L-3.0 mol / L is selected as the eluent to ensure that the eluent completely immerses the cation exchange resin column adsorbed with amino acid ions, and the column is immersed for 30 min-45 min, and the stirring is continued, and the stirring rate is controlled to be 20 r / min-40 r / min. After the immersion is completed, the outlet valve of the elution container is opened, the eluent is slowly discharged, and the eluent containing amino acids is collected.

[0022] In one embodiment of the present invention: in step three, the collected eluate is transferred to a concentrator, concentrated under reduced pressure at low temperature, the temperature of the concentrator is set to 45°C-50°C, and the pressure is controlled between -0.08MPa--0.10MPa. Under this condition, the water in the eluate is slowly evaporated, and the amino acid solution is slowly concentrated. During the evaporation and concentration process, the volume change of the amino acid solution is observed, and the concentration operation is stopped when the volume of the amino acid solution is reduced to 1 / 4-1 / 3 of the original amino acid solution.

[0023] In one embodiment of the present invention: in step 4, according to the needs of different crops and soil conditions, the total addition amount of nitrogen, phosphorus, potassium and trace elements is determined to be 5%-8% of the total amount of the concentrated amino acid solution, and the concentrated amino acid solution is transferred to a mixing container with a stirring device. Urea and ammonium nitrate are selected as nitrogen sources, potassium dihydrogen phosphate and superphosphate are selected as phosphorus sources, and potassium sulfate and potassium chloride are selected as potassium sources. Among them, trace elements include iron, zinc and boron. Humic acid and alginate can be added during the preparation process. The addition amount of humic acid accounts for 5g-10g per kilogram of fertilizer, and the addition amount of alginate accounts for 2g-5g per kilogram of fertilizer.

[0024] In one embodiment of the present invention: in step five, nano calcium carbonate is selected as the nano material, the prepared amino acid fertilizer is placed in a stirring container, 3%-5% of the total mass of the fertilizer is slowly added with nano calcium carbonate, and stirred at a stirring rate of 40r / min-60r / min for 20min-30min. During the stirring process, 1%-2% of the total mass of the nano calcium carbonate is added with sodium dodecylbenzene sulfonate. After the stirring is completed, it is ensured that the nano material is evenly coated on the surface of the fertilizer particles, and the coated fertilizer product is transferred to a spray drying device. Using a spray dryer, the inlet temperature is set to 120°C-150°C, and the outlet temperature is set to 70°C-90°C. The fertilizer is sprayed into the dryer to quickly evaporate the water in the fertilizer to form a dry nano particle fertilizer.

[0025] In one embodiment of the present invention: when drying the amino acid fertilizer wrapped with nanoparticles, a freeze dryer can be used to dry it. First, the finished fertilizer is frozen to below 40°C, and then sublimation drying is performed under vacuum conditions to directly change the water in the fertilizer from solid to gas, thereby achieving the purpose of drying.

[0026] In one embodiment of the present invention: the activated carbon is selected from coconut shell activated carbon that has undergone special activation treatment, and the micropores in its pore structure account for more than 70%. The high-purity alanine fermentation liquid is added to a reactor with a precise temperature control device. The jacket of the reactor is heated by heat transfer oil, and the heating is uniform and the temperature control accuracy is ±0.5°C. The stirrer is turned on, and the stirring paddle adopts a double-layer combined structure. The upper layer is a propulsion stirring paddle for rapid mixing, and the lower layer is an anchor stirring paddle to ensure that the bottom material is fully stirred. The stirring rate is adjusted in stages within the range of 60r / min-90r / min, and is first stirred at a speed of 60r / min for 10m in, and then gradually increased to 90r / min, maintained for 20min and then dropped back to 60r / min. During the adsorption reaction, the absorbance change of the fermentation liquid was detected in real time by online monitoring equipment to reflect the impurity adsorption situation. When the absorbance dropped to below 30% of the initial value, it was considered that the adsorption was close to equilibrium. After the adsorption was completed, the activated carbon was separated by a combination of static stratification and microfiltration. It was first allowed to stand for 50min-70min to allow the activated carbon to settle naturally, and then filtered through the microporous filter plate at the bottom. The pore size of the filter plate was 3um-5um. A slight negative pressure was applied during the filtration process, with a pressure of -0.02MPa- -0.04MPa, to speed up the filtration speed.

[0027] In one embodiment of the present invention: the surface-modified nano calcium carbonate is selected, and the surface has hydrophilic groups, the average particle size is 40nm-60nm, and the particle size distribution is uniform. The prepared amino acid fertilizer is placed in a closed stirring container with vacuum extraction, heating and stirring functions. The stirring container adopts a double-layer jacket structure, and heat transfer oil or hot water can be introduced into the jacket for temperature control. The fertilizer is first vacuumed to a vacuum degree of -0.05MPa- -0.07MPa, maintain for 8min-12min, remove air and moisture in the fertilizer, and then slowly add 3%-5% of the total mass of nano calcium carbonate of the fertilizer, start stirring during the addition process, and the stirring rate is gradually and steadily increased from 40r / min to 60r / min, and the increase time is 3min-5min. During the stirring process, the temperature is accurately controlled at 35℃-45℃ by the heating device, and the accuracy of the temperature sensor is ±0.2℃. After adding nano calcium carbonate, continue stirring for 20min-30min, and then add 1%-2% of the total mass of nano calcium carbonate sodium dodecylbenzene sulfonate. After stirring, use a laser particle size analyzer and a scanning electron microscope to detect the particle size distribution and surface morphology of the fertilizer particles to ensure that the nanomaterials are evenly coated on the surface of the fertilizer particles, and the particles with a particle size distribution between 80um-600um account for more than 75%, and the surface coating layer is uniform and dense.

[0028] In one embodiment of the present invention: the strongly acidic cation exchange resin is a macroporous resin with high exchange capacity and selectivity, the exchange capacity of the resin is greater than 4.5mmol / g, the resin column is made of corrosion-resistant glass fiber reinforced plastic, the column is strengthened and can withstand higher pressure, the resin column is pretreated before filling the resin, first soaked in deionized water for 24h, then alternately soaked in 1mol / L sodium hydroxide solution and 1mol / L hydrochloric acid solution for 3 times, each soaking time is 2h, and finally rinsed with deionized water until neutral, the treated resin is filled into the resin column at a uniform speed, a vibrator is used to assist in the filling process to ensure that the resin is filled tightly and evenly, the filling height is 70cm-90cm, and after the filling is completed, the deionized water is used to remove the resin. The resin is flushed and pretreated with sub-water at a flow rate of 1.5BV / h-2.5BV / h until the conductivity of the effluent is lower than 50uS / cm. The crude alanine fermentation broth after ultrasonic treatment is pumped into the resin column through a high-precision metering pump at a flow rate of 4BV / h-6BV / h. The flow error of the metering pump is controlled within ±1%. A plurality of distributed temperature sensors are arranged around the resin column to monitor the temperature changes of different parts of the resin column in real time, and the temperature is controlled at 28℃-32℃ through an automatic temperature control device, and the temperature fluctuation range is less than ±1℃. During the adsorption process, samples are taken from the effluent every 20min-40min, and the amino acid content is detected by ion chromatography. When the amino acid content in the effluent reaches 8%-12% of the feed liquid content, the feeding is stopped.

[0029] Embodiment 1 First, the alanine fermentation broth was pretreated, and was initially filtered using a 100um stainless steel filter at 25°C and 50r / min stirring, then filtered through a 50um polypropylene filter membrane at a flow rate of 50L / h, and then deeply filtered through a 10um polytetrafluoroethylene filter membrane at a pressure of 0.1MPa to obtain a high-purity alanine fermentation broth. The high-purity alanine fermentation broth was added to the reactor, and coconut shell activated carbon accounting for 4% of the total mass of the alanine fermentation broth was added. The stirrer was turned on and stirred at 60r / min, the temperature in the reactor was raised to 38°C, and the adsorption reaction was stopped after 2h of stirring and allowed to stand for 45 min, and then filter it through a 5um filter membrane to obtain a crude alanine fermentation broth, transfer the crude alanine fermentation broth to an ultrasonic treatment container, adjust the ultrasonic frequency to 35kHz, the power to 120W, ultrasonic treatment for 40min, keep the fermentation broth temperature at 30°C, stir at a stirring rate of 40r / min, select a strong acid cation exchange resin column, rinse it with deionized water and soak the resin with a 2mol / L hydrochloric acid solution, pass the ultrasonically treated crude alanine fermentation broth through the strong acid cation exchange resin column at a flow rate of 4BV / h, keep the temperature at 28°C, and then The exchange column was immersed in a container filled with 2.5 mol / L hydrochloric acid solution for elution for 30 min. The hydrochloric acid solution was stirred at 20 r / min. The amino acid solution was collected and transferred to a concentration device. It was concentrated under reduced pressure at 45°C and -0.08 MPa until the volume of the amino acid solution was reduced to 1 / 4 of the original solution. Then the concentration operation was stopped. According to the crop requirements and soil conditions, the total amount of nitrogen, phosphorus, potassium and trace elements added was determined to be 5% of the total amount of the concentrated amino acid solution. Urea was selected as the nitrogen source, potassium dihydrogen phosphate was selected as the phosphorus source, potassium sulfate was selected as the potassium source, and humic acid and alginic acid were added (humic acid per kg of fertilizer 5g, 2g of alginate per kilogram of fertilizer) are stirred evenly to prepare amino acid fertilizer, nano calcium carbonate with an average particle size of 40nm is selected, the prepared amino acid fertilizer is put into a stirring container, 3% of the total mass of the fertilizer is added with nano calcium carbonate, and stirred at a stirring rate of 40r / min for 20min, and then sodium dodecylbenzene sulfonate accounting for 1% of the total mass of the nano calcium carbonate is added. After stirring, ensure that the nano material evenly wraps the amino acid fertilizer, transfer the wrapped amino acid fertilizer product to a spray drying equipment, set the inlet temperature to 120℃, the outlet temperature to 70℃, and obtain the amino acid fertilizer after drying.

[0030] Embodiment 2 The alanine fermentation broth was filtered through a 100um stainless steel filter at 28°C and 65r / min stirring, and then filtered through a 50um polypropylene filter membrane at a flow rate of 55L / h, and then filtered through a 10um polytetrafluoroethylene filter membrane at a pressure of 0.15MPa to obtain a high-purity alanine fermentation broth. The high-purity alanine fermentation broth was added to a reactor, and coconut shell activated carbon accounting for 5% of the total mass of the high-purity alanine fermentation broth was added. The stirrer was turned on and stirred at 60r / min for 10min, then increased to 80r / min after stirring for 20min, and finally reduced back to 60r / min for continued stirring. The temperature in the reactor was maintained at 42°C, and the adsorption reaction was continued for 4 hours. h and then allowed to stand for 50 min, filtered through a microporous filter plate with a bottom pore size of 4 um under a slight negative pressure of -0.03 MPa to obtain a crude alanine fermentation broth, transferred the crude alanine fermentation broth to an ultrasonic treatment container, adjusted the ultrasonic frequency to 40 kHz, the power to 135 W, ultrasonically treated for 50 min, and the fermentation broth temperature was maintained at 33 ° C, stirred continuously during the ultrasonic process, and the stirring rate was controlled to be 50 r / min. A strong acid cation exchange resin column was selected, soaked in deionized water for 24 h, and then alternately soaked in a sodium hydroxide solution and a hydrochloric acid solution with a concentration of 1 mol / L for 3 times, each time for 2 h, and finally rinsed with deionized water until neutral and filled into the resin column, and deionized water was used to The fermentation liquid after ultrasonic treatment was pre-treated by flushing at a flow rate of 2BV / h, and the fermentation liquid after ultrasonic treatment was pumped into the resin column at a flow rate of 5BV / h through a metering pump, and the temperature was controlled between 28°C and 32°C. The strong acid cation exchange resin column adsorbed with amino acid ions was immersed in a container filled with an eluent, and eluted with a hydrochloric acid solution with a concentration of 2.8mol / L, and soaked for 38min. During the elution process, the stirring rate was controlled to be 30r / min. After the elution was completed, the amino acid solution was collected and transferred to a concentration device, and reduced pressure was concentrated at 48°C and -0.09MPa until the volume of the amino acid solution was reduced to 1 / 3 of the original solution, and then nitrogen, phosphorus, potassium and trace elements were added, and the total amount added was the concentrated amino acid solution. 6% of the total amount, ammonium nitrate is selected as the nitrogen source, superphosphate is selected as the phosphorus source, potassium chloride is selected as the potassium source, humic acid and alginic acid are added (7g of humic acid per kilogram of fertilizer, 3g of alginate per kilogram of fertilizer) and stirred evenly to make fertilizer, nano calcium carbonate with an average particle size of 50nm is selected, put into a stirring container, 4% of the total mass of amino acid fertilizer is added with nano calcium carbonate, the stirring rate is controlled at 50r / min, stirred at 40℃ for 25min, and then sodium dodecylbenzene sulfonate accounting for 1.5% of the total mass of nano calcium carbonate is added to ensure that the nano material evenly wraps the fertilizer particles, and finally a spray drying equipment is used, the inlet temperature is set to 135℃, and the outlet temperature is set to 80℃, and it is dried to obtain amino acid fertilizer.

[0031] Embodiment 3 The alanine fermentation broth was initially filtered through a 100um stainless steel filter at 30°C and a stirring rate of 70r / min, and then filtered through a 50um polypropylene filter membrane at a flow rate of 58L / h. Finally, it was deeply filtered through a 10um polytetrafluoroethylene filter membrane at a pressure of 0.2MPa. The high-purity alanine fermentation broth was added to the reactor, and coconut shell activated carbon accounting for 6% of the total mass of the high-purity alanine fermentation broth was added. The stirrer was turned on and stirred at 75r / min, and the temperature in the reactor was raised to 45°C. After the adsorption reaction for 6h, the stirring was stopped and then allowed to stand for 60min. The crude alanine fermentation broth was filtered through a 5um filter membrane, and the crude alanine fermentation broth was transferred to an ultrasonic treatment container. The ultrasonic frequency was set to 45kHz, the power was 150W, the ultrasonic treatment was performed for 60min, the temperature was controlled to 35°C, the stirring rate was 60r / min, and a treated strong acid cation exchange resin column was selected. The crude alanine fermentation broth after ultrasonic treatment was passed through the resin column at a flow rate of 6BV / h, and the temperature was maintained at 32°C. The exchange column adsorbed with amino acid ions was immersed in a container filled with a 3.0mol / L hydrochloric acid solution for 45min, and the elution was performed. During the process, the eluent was stirred continuously at a stirring rate of 40r / min. After the elution was completed, the amino acid solution was collected and transferred to a concentration device for reduced pressure concentration at 50°C and -0.10MPa. When the volume of the amino acid solution was reduced to 1 / 4 of the original solution, nitrogen, phosphorus, potassium and trace elements were added. The total amount added was 8% of the total amount of the concentrated amino acid solution. The nitrogen source was a mixture of urea and ammonium nitrate, the phosphorus source was a mixture of potassium dihydrogen phosphate and superphosphate, and the potassium source was a mixture of potassium sulfate and potassium chloride. Humic acid and alginic acid were added (10g of humic acid per kilogram of fertilizer, 10g of alginic acid per kilogram of fertilizer). 5g of fertilizer), mixed evenly to form amino acid fertilizer, nano calcium carbonate with an average particle size of 60nm was selected, the prepared amino acid fertilizer was put into a stirring container, and 5% of the total mass of the fertilizer was added with nano calcium carbonate, and stirred at a stirring rate of 60r / min for 30min, and sodium dodecylbenzene sulfonate accounting for 2% of the total mass of the nano calcium carbonate was added during the stirring process. After the stirring was completed, it was tested to ensure that the nano material evenly wrapped the amino acid fertilizer, and the finished fertilizer was transferred to a spray drying equipment, the inlet temperature was set to 150°C, and the outlet temperature was set to 90°C, and it was dried to obtain the amino acid fertilizer.

[0032] Embodiment 4: Take an appropriate amount of alanine fermentation broth and use a stainless steel filter with a pore size of 100um to perform preliminary filtration at a temperature of 26°C and a stirring rate of 55r / min, then finely filter through a polypropylene filter membrane with a pore size of 50um at a flow rate of 52L / h, and then deep filter through a polytetrafluoroethylene filter membrane with a pore size of 10um at a pressure of 0.12MPa to obtain high-purity alanine fermentation broth, add the high-purity alanine fermentation broth to the reactor, add coconut shell activated carbon accounting for 4.5% of the total mass of the high-purity alanine fermentation broth, turn on the stirrer, stir at 60r / min for 8min, then gradually increase to 85r / min for 22min, and then adjust back to 60r / min for continued stirring, and at the same time, The temperature in the kettle was raised to 40°C, and the adsorption reaction was carried out for 3 hours. After the reaction was completed, stirring was stopped to allow the coconut shell activated carbon to precipitate naturally for 55 minutes, and then the crude alanine fermentation broth was filtered through a fine filter membrane with a pore size of 4.5um to obtain the crude alanine fermentation broth. The crude alanine fermentation broth was transferred to an ultrasonic treatment container, the ultrasonic frequency was adjusted to 38kHz, the power was set to 130W, and the ultrasonic treatment was continued for 45 minutes. During the ultrasonic process, the fermentation broth temperature was maintained at 32°C, and the stirring was carried out at a rate of 45r / min. A strong acid cation exchange resin column was selected, and after pretreatment with deionized water, the crude alanine fermentation broth after ultrasonic treatment was pumped into the resin column using a high-precision metering pump at a flow rate of 4.5BV / h, and the temperature was maintained at 29℃, during the adsorption process, the amino acid content in the effluent was detected every 35min, and the feeding was stopped when the set standard was reached. The exchange column adsorbed with amino acid ions was placed in a container filled with a hydrochloric acid solution with a concentration of 2.6mol / L and soaked for 35min, and the hydrochloric acid solution was continuously stirred, and the stirring rate was controlled at 25r / min. After the soaking, the amino acid solution was collected and transferred to a concentration device, and reduced pressure concentration was carried out under the conditions of a temperature of 46℃ and a pressure of -0.085MPa. The operation was stopped when the volume of the amino acid solution was reduced to 1 / 3 of the original solution, and nitrogen, phosphorus, potassium and trace elements were added. The total addition amount was 6.5% of the total amount of the concentrated amino acid solution. Urea and ammonium nitrate were selected as the nitrogen source at a ratio of 1: The mixture was mixed in a certain proportion. The phosphorus source was potassium dihydrogen phosphate and superphosphate, the potassium source was potassium sulfate and potassium chloride, the trace elements included iron, zinc, boron, etc., humic acid and alginic acid were added (humic acid 6g per kilogram of fertilizer, alginate 3.5g per kilogram of fertilizer), and the amino acid fertilizer was made by stirring evenly. Nano calcium carbonate with an average particle size of 45nm was selected. The prepared amino acid fertilizer was placed in a closed container with vacuum extraction, heating and stirring functions. The vacuum was first evacuated to -0.06MPa and maintained for 10 minutes. Then, nano calcium carbonate accounting for 3.5% of the total mass of the fertilizer was slowly added. The stirring rate was 40r / min. The mixture was stirred at 38°C for 22 minutes. Then, 1.2% sodium dodecylbenzene sulfonate, after stirring, test to ensure that the nanomaterials are evenly coated on the surface of the amino acid fertilizer particles, and finally transfer the finished fertilizer to the spray drying equipment, set the inlet temperature to 130℃, the outlet temperature to 75℃, and dry it to obtain the amino acid fertilizer.

[0033] Embodiment 5 The alanine fermentation broth was initially filtered through a stainless steel filter at 27°C and 60r / min stirring, and then filtered through a polypropylene filter membrane at a flow rate of 56L / h, and then deeply filtered through a polytetrafluoroethylene filter membrane at a pressure of 0.18MPa. The high-purity alanine fermentation broth was added to the reactor, and coconut shell activated carbon accounting for 5.5% of the total mass of the high-purity alanine fermentation broth was added. The stirrer was turned on and stirred at 70r / min, and the temperature in the reactor was raised to 43°C. After the adsorption reaction for 5h, the stirring was stopped and the mixture was allowed to stand for 55min. The crude alanine fermentation broth was obtained by filtration through a filter membrane, and the crude alanine fermentation broth was obtained. The fermentation liquid was transferred to an ultrasonic treatment container, and the ultrasonic frequency was set to 42kHz, the power was 140W, the ultrasonic treatment was performed for 55min, the treatment temperature was maintained at 34°C, stirring was continued during the ultrasonic process, the stirring rate was 55r / min, a strong acid cation exchange resin column was selected, and after pretreatment, the crude alanine fermentation liquid after ultrasonic treatment was passed through the resin column at a flow rate of 5.5BV / h, and the temperature was controlled at 31°C. After the adsorption was completed, the exchange column adsorbed with amino acid ions was immersed in a container containing an eluent, and eluted with a hydrochloric acid solution with a concentration of 2.7mol / L for 40min, and stirred. The stirring rate is 35r / min. After collecting the amino acid solution, transfer it to the concentration device and concentrate it under reduced pressure at 49°C and -0.095MPa. When the volume of the amino acid solution is concentrated to 1 / 3 of the original solution, stop adding nitrogen, phosphorus, potassium and trace elements. The total amount added is 7% of the total amount of the concentrated amino acid solution. Ammonium nitrate is selected as the nitrogen source, potassium dihydrogen phosphate is selected as the phosphorus source, potassium chloride is selected as the potassium source, and the trace elements are iron, zinc and boron. Humic acid and alginic acid are added (8g of humic acid per kilogram of fertilizer, 4g of alginic acid per kilogram of fertilizer), and mixed evenly to make amino acid fertilizer. Flat The average particle size of nano calcium carbonate is 55nm. The prepared amino acid fertilizer is put into a stirring container, and 4.5% of the total mass of the amino acid fertilizer is added with nano calcium carbonate. The mixture is stirred at a stirring rate of 50r / min for 28min. Then, sodium dodecylbenzene sulfonate accounting for 1.8% of the total mass of the nano calcium carbonate is added. After stirring, the finished amino acid fertilizer is tested to ensure that the nano material evenly wraps the amino acid fertilizer. The finished fertilizer is then frozen to below 40°C and sublimated and dried under vacuum conditions to change the water in the fertilizer directly from solid to gas. The amino acid fertilizer is obtained after drying.

[0034] The amino acid fertilizers prepared in the above five groups of embodiments were tested, and the specific testing steps were as follows: Appearance inspection, Direct observation method: In a well-lit environment, place the finished amino acid fertilizer on a white background and observe its color, shape, presence of impurities, lumps, etc. directly with the naked eye.

[0035] Moisture determination, Accurately weigh a certain mass of amino acid fertilizer sample and put it into a weighing bottle that has been pre-dried to a constant weight. Put the weighing bottle and the sample into an oven, set the temperature to about 105°C, and dry them to a constant weight. Calculate the moisture content based on the mass difference before and after drying.

[0036] pH determination, Weigh a certain amount of amino acid fertilizer sample, put it into a beaker, add deionized water with a mass ratio of 1:10 between the amino acid fertilizer sample and deionized water, stir with a glass rod to fully dissolve it, insert the calibrated pH meter electrode into the solution, and record the pH value after the reading stabilizes.

[0037] Nutrient content testing, Nitrogen content detection: Kjeldahl method.

[0038] Sample digestion: Mix the amino acid fertilizer sample with concentrated sulfuric acid and a catalyst (such as copper sulfate, potassium sulfate), heat and digest it to convert organic nitrogen into ammonium nitrogen. Distill the digested solution to release the ammonium nitrogen in the form of ammonia gas, absorb it with boric acid solution, titrate the absorbed solution with standard hydrochloric acid solution, and calculate the nitrogen content based on the amount of hydrochloric acid used.

[0039] Phosphorus content detection: Molybdenum antimony anti-spectrophotometry, Sample processing: Dissolve the fertilizer sample with acid to prepare the test solution, add molybdenum antimony anticolorimetric agent to the test solution to make phosphorus react with it to form a colored compound, measure the absorbance at a specific wavelength with a spectrophotometer, and calculate the phosphorus content according to the standard curve.

[0040] Potassium content detection: flame photometry, Sample preparation: Dissolve the fertilizer sample to make a solution, introduce the solution into the flame photometer, measure the intensity of light of a specific wavelength emitted by the potassium element, and calculate the potassium content based on the standard curve.

[0041] The test data of the finished fertilizer products in the five groups of embodiments are calculated as follows: Embodiment 1

[0042] Appearance: Off-white particles, without obvious impurities or lumps; Moisture content: 3.5%; pH: 6.8; Nitrogen content: 12.5%; Phosphorus content: 8.2; Potassium content: 10.1.

[0043] Embodiment 2 Appearance: White uniform particles, a small amount of impurities, no lumps; Moisture content: 4.0%; pH: 7.0; Nitrogen content: 13.2; Phosphorus content: 8.5; Potassium content: 10.5.

[0044] Embodiment 3 Appearance: light yellow granules, no impurities, no lumps; Moisture content: 3.8%; pH: 6.5; Nitrogen content: 12.8%; Phosphorus content: 8.0; Potassium content: 10.3.

[0045] Embodiment 4: Appearance: Light grey particles, no impurities, slight agglomeration; Moisture content: 3.6%; pH: 6.9; Nitrogen content: 13.0%; Phosphorus content: 8.3; Potassium content: 10.2.

[0046] Embodiment 5 Appearance: White loose particles, no impurities, no lumps; Moisture content: 3.9%; pH: 7.1; Nitrogen content: 12.7%; Phosphorus content: 8.1; Potassium content: 10.4.

[0047] In summary, the feasibility and effectiveness of extracting amino acids from alanine fermentation broth to prepare fertilizers in the five embodiments of the present invention have important practical significance and application value.

[0048] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions and variations of these embodiments are made without departing from the principles and spirit of the present invention, and still fall within the scope of protection of the present invention.

[0049] In the description of the specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0050] The above contents are merely examples and explanations of the present invention. Various modifications or additions to the specific embodiments described or replacements in similar ways by technicians in the technical field shall fall within the protection scope of the present invention as long as they do not deviate from the invention or exceed the scope defined by the claims.

[0051] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for extracting amino acids from alanine fermentation broth to prepare fertilizer, comprising pretreatment of the alanine fermentation broth, ion exchange adsorption, elution, concentration and fertilizer preparation, characterized in that: The specific operation steps of extracting amino acids from alanine fermentation broth to prepare fertilizer are as follows: Step 1, pre-treating the alanine fermentation broth, obtaining a high-purity alanine fermentation broth after three groups of filtration, and obtaining a crude alanine fermentation broth after adding activated carbon for adsorption; Step 2: ultrasonically treat the adsorbed crude alanine fermentation broth and then perform ion exchange adsorption, control the flow rate and temperature of the crude alanine fermentation broth, and prepare an exchange column adsorbed with amino acid ions; Step 3, immersing the exchange column adsorbed with amino acid ions into an eluent, eluting the amino acids from the ion exchange resin, and concentrating the eluent to obtain a concentrated amino acid solution; Step 4: Add nitrogen, phosphorus, potassium and trace elements to the concentrated amino acid solution, mix and prepare according to the proportion to make amino acid fertilizer; Step 5: Use nanoparticles to encapsulate the prepared amino acid fertilizer to prepare a stable nanoparticle fertilizer, and dry it to obtain a finished amino acid fertilizer.

2. A method for extracting amino acids from alanine fermentation broth to prepare fertilizer according to claim 1, characterized in that: In the step 1, the alanine fermentation liquid is passed through a stainless steel filter with a pore size of 100 μm, and the alanine fermentation liquid is continuously stirred to make it pass through the filter evenly, and the larger particle impurities and incompletely fermented solid residues are initially filtered out, the stirring temperature is 25° C.-30° C., and the stirring rate is 50 r / min-80 r / min. The initially filtered alanine fermentation liquid is passed through a polypropylene filter membrane with a pore size of 50 μm, and the alanine fermentation liquid is pressurized to stably pass through the polypropylene filter membrane, and the smaller particle impurities are removed by fine filtration, and the flow rate is controlled between 50 L / h-60 L / h. The finely filtered alanine fermentation liquid is passed through a polytetrafluoroethylene filter membrane with a pore size of 10 μm, and the pressure is controlled between 0.1 MPa-0.2 MPa. After deep filtration, a high-purity alanine fermentation liquid is obtained.

3. The method for preparing fertilizer by extracting amino acids from alanine fermentation broth according to claim 1, characterized in that: In the step 1, the high-purity alanine fermentation broth is added to a reactor equipped with a stirrer and a heating device, 4%-6% of the total mass of the high-purity alanine fermentation broth is added with granular activated carbon, the stirrer is turned on, the stirring rate is controlled to be 60r / min-90r / min, the activated carbon and the fermentation broth are fully mixed, and the heating device is turned on at the same time, the temperature in the reactor is increased to 38°C-45°C, an adsorption reaction is carried out, and after adsorption for 2h-6h, the stirring is stopped, the activated carbon is naturally precipitated in the reactor for 45min, the fermentation broth on the upper layer is slowly drawn out, and it is passed through a fine filter membrane with a pore size of 5um to obtain a crude alanine fermentation broth.

4. The method for preparing fertilizer by extracting amino acids from alanine fermentation broth according to claim 1, characterized in that: In the step 2, the crude alanine fermentation liquid is transferred to an ultrasonic treatment container, the ultrasonic frequency is adjusted to 35kHz-45kHz, and the power is 120W-150W. Within this range, the ultrasonic treatment is continued for 40min-60min. During the ultrasonic process, the temperature of the fermentation liquid is maintained at 30°C-35°C, and the crude alanine fermentation liquid is continuously stirred, and the stirring rate is controlled to be 40r / min-60r / min.

5. The method for preparing fertilizer by extracting amino acids from alanine fermentation broth according to claim 1, characterized in that: In the step 2, a strong acid cation exchange resin column is selected, and the strong acid cation exchange resin column is rinsed with deionized water to remove impurities and residual chemical substances therein, and the resin is soaked with a hydrochloric acid solution with a concentration of 2 mol / L-3 mol / L, and the crude alanine fermentation broth after ultrasonic treatment is passed through the strong acid cation exchange resin column at a flow rate of 4 BV / h-6 BV / h, while maintaining the temperature between 28° C. and 32° C. During the adsorption process, it is necessary to detect the content of amino acids in the effluent, and when the concentration of amino acids in the distillate reaches a certain value, the feeding is stopped.

6. The method for preparing fertilizer by extracting amino acids from alanine fermentation broth according to claim 1, characterized in that: In the step three, the exchange column adsorbed with amino acid ions is immersed in a container filled with an eluent, a hydrochloric acid solution with a concentration of 2.5 mol / L-3.0 mol / L is selected as the eluent, and the eluent is ensured to completely immerse the cation exchange resin column adsorbed with amino acid ions, and the column is immersed for 30 min-45 min, and the stirring is continued, and the stirring rate is controlled to be 20 r / min-40 r / min. After the immersion is completed, the outlet valve of the elution container is opened, the eluent is slowly discharged, and the eluent containing amino acids is collected.

7. The method for preparing fertilizer by extracting amino acids from alanine fermentation broth according to claim 1, characterized in that: In the step 3, the collected eluate is transferred to a concentrator and concentrated under reduced pressure at low temperature. The temperature of the concentrator is set to 45°C-50°C, and the pressure is controlled between -0.08MPa--0.10MPa. Under this condition, the water in the eluate is slowly evaporated and the amino acid solution is slowly concentrated. During the evaporation and concentration process, the volume change of the amino acid solution is observed. When the volume of the amino acid solution is reduced to 1 / 4-1 / 3 of the original amino acid solution, the concentration operation is stopped.

8. The method for preparing fertilizer by extracting amino acids from alanine fermentation broth according to claim 1, characterized in that: In the step 4, according to the needs of different crops and soil conditions, the total amount of nitrogen, phosphorus, potassium and trace elements added is determined to be 5%-8% of the total amount of the concentrated amino acid solution, and the concentrated amino acid solution is transferred to a mixing container with a stirring device. Urea and ammonium nitrate are selected as nitrogen sources, potassium dihydrogen phosphate and superphosphate are selected as phosphorus sources, and potassium sulfate and potassium chloride are selected as potassium sources. Among them, trace elements include iron, zinc and boron. Humic acid and alginate can be added during the preparation process. The amount of humic acid added is 5g-10g per kilogram of fertilizer, and the amount of alginate added is 2g-5g per kilogram of fertilizer.

9. The method for preparing fertilizer by extracting amino acids from alanine fermentation broth according to claim 1, characterized in that: In the step 5, nano calcium carbonate is selected as the nano material, the prepared amino acid fertilizer is placed in a stirring container, 3%-5% of the total mass of the fertilizer is slowly added with nano calcium carbonate, and the mixture is stirred at a stirring rate of 40 r / min-60 r / min for 20 min-30 min. During the stirring process, 1%-2% of the total mass of the nano calcium carbonate is added with sodium dodecylbenzene sulfonate. After the stirring is completed, it is ensured that the nano material is evenly coated on the surface of the fertilizer particles, and the coated fertilizer product is transferred to a spray drying device. The spray dryer is used, the inlet temperature is set to 120° C.-150° C., and the outlet temperature is set to 70° C.-90° C., the fertilizer is sprayed into the dryer, and the water in the fertilizer is rapidly evaporated to form a dry nano particle fertilizer.

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