A biomass composite water culture solution and its preparation method

Abstract

The present invention relates to a biomass composite water culture solution and a preparation method thereof, belonging to the technical field of plant hydroponics. The culture solution is composed of 12 core components such as straw enzymolysis solution, humic acid, seaweed extract, nitrogen-phosphorus-potassium compound fertilizer, silver / carbon microsphere composite bacteriostatic agent, and polylactic acid-glycolic acid copolymer loaded with EM composite probiotics. Its preparation is achieved through a step-by-step mixing process: first, the straw enzymolysis solution is mixed with basic components such as humic acid, then the seaweed extract and probiotic carrier are respectively treated, and finally, step-by-step mixing is carried out to ensure the stability of the components. The present invention uses calcium carbonate-hydrogen peroxide pretreatment combined with cellulose complex enzymolysis technology to improve the utilization rate of straw; prepares polylactic acid-glycolic acid copolymer loaded with EM composite probiotics by the W / O / W double emulsion method; silver / carbon microspheres and potassium sorbate have a synergistic bacteriostatic effect; composite plant hormones precisely regulate growth. The culture solution has the functions of nutrient supply, antibacterial protection, and growth regulation.

Description

Technical Field

[0001] The present invention belongs to the technical field of agricultural planting, and specifically relates to a biomass composite water culture solution and a preparation method thereof, which are applicable to scenarios such as plant soilless cultivation, home gardening, and plant factories. Background Art

[0002] Traditional water culture solutions mostly rely on chemically synthesized nutrient salts, and have problems such as single composition, easy to cause secondary salinization of the soil, and poor biocompatibility. In the prior art, although the nutrient solution containing plant extracts is proposed in CN109553486A, its utilization of biomass resources is insufficient, and there is a lack of optimized design for the synergistic effect of microorganisms. In addition, soilless cultivation nutrient solutions generally have the defects of poor stability and easy to breed pathogenic bacteria. For example, although the EM probiotic is introduced in the patent application CN201310493349A, the biomass pretreatment technology is not combined, resulting in low nutrient release efficiency.

[0003] Existing water culture solutions have problems such as single composition, poor water and fertilizer retention capacity (swelling rate ≤ 30%), and high cost. The traditional preparation method does not functionalize biomass materials, resulting in insufficient stability in complex environments and restricting their application in water-saving agriculture and ecological restoration fields. Summary of the Invention

[0004] Object of the Invention: The object of the present invention is to provide a hydroponic nutrient solution based on biomass materials and a preparation method thereof, so as to solve the problems of single composition, poor water and fertilizer retention capacity, etc. existing in the existing water culture solutions.

[0005] Technical Solution: A hydroponic nutrient solution based on biomass materials, comprising the following components in parts by weight: 30 - 40 parts of straw enzymolysis solution, 20 - 25 parts of humic acid, 5 - 7 parts of seaweed extract, 3 - 5 parts of nitrogen, phosphorus and potassium compound fertilizer with N:P2O5:K2O = 15:15:15, 0.5 - 0.7 parts of silver / carbon microsphere composite bacteriostatic agent, 2 - 5 parts of poly(lactic-co-glycolic acid) loaded EM composite probiotic, 10 - 15 parts of glucose, 1000 - 1200 parts of water, 0.005 - 0.01 parts of composite plant hormone, 6 - 9 parts of low-salt soy sauce, 0.1 - 0.3 parts of β-glucan, 0.05 - 0.1 parts of potassium sorbate, 0.4 - 0.8 parts of EDTA chelated trace metal mixture.

[0006] Preferably, the method for preparing the straw enzymatic hydrolysate is as follows: The straw is crushed and sieved through a 30-mesh sieve, and then soaked in a calcium carbonate-hydrogen peroxide mixed aqueous solution with a mass ratio of 9-10:1. After soaking, it is left standing at 120-130 °C for 70-80 min to obtain straw b. Then, straw b is added to deionized water with a weight 9-10 times that of straw b, and left standing at 40-60 °C for 10-30 min to obtain straw c. Straw c is placed in an oven at 60-80 °C and dried to a constant weight. Then, it is subjected to high-pressure steam sterilization at 120-125 °C for 20-30 min to obtain straw d. Straw d and water are fed into an enzymatic hydrolysis tank at 60-65 °C at a mass ratio of 1:10, and 1% sodium dihydrogen phosphate buffer aqueous solution is added to the uniformly stirred enzymatic hydrolysis raw material to adjust the pH value to 4.8-6.6. Then, a cellulose complex enzyme containing 1%-3% surfactant is added to the enzymatic hydrolysis tank in a sealed state. The cellulose complex enzyme is composed of endoglucanase, exoglucanase, and cellobiase with a mass ratio of 1:1:2. After the COD of the enzymatic hydrolysis product in the enzymatic hydrolysis tank no longer changes, the enzymatic hydrolysis reaction ends to obtain the straw enzymatic hydrolysate.

[0007] Preferably, the method for preparing the seaweed extract is as follows: The fresh seaweed is rinsed with clean water to remove impurities such as sediment, salt, and epiphytic organisms, and dried at a low temperature of 40-60 °C. The dried seaweed is ground into a powder with a mesh size of 20-100 by a pulverizer. The seaweed powder and deionized water are mixed in a ratio of 1:10~1:30 and heated to 60-100 °C, and stirred and extracted for 1-4 h. The residue is removed by centrifugation, and the supernatant is collected and the water is removed by vacuum evaporation to obtain the product.

[0008] Preferably, the method for preparing the silver / carbon microsphere composite antibacterial agent is as follows: Weigh glucose, and add silver nitrate with a weight 1 / 5 of that of glucose and dissolve it in deionized water with a weight 10 times that of glucose, and transfer it to a reaction kettle. React at 180 °C for 7 h. After the reaction kettle naturally cools to room temperature, the product is washed several times with deionized water and absolute ethanol respectively, and dried at 85 °C for 4 h to obtain a brown powder.

[0009] Preferably, the preparation method of the poly(lactic-co-glycolic acid) copolymer loaded with EM composite probiotics is as follows: Dissolve poly(lactic-co-glycolic acid) (PLGA) with a relative molecular weight of 15 kDa in ethyl acetate with 9 times its weight, stir magnetically until completely dissolved, culture the EM composite probiotics until the logarithmic growth phase, collect the bacterial cells by centrifugation, resuspend them in a phosphate buffer solution containing 10% trehalose at pH 7.4, slowly add the bacterial suspension to a PLGA solution with 10 times the volume of the bacterial suspension, and perform ultrasonic treatment at 40% amplitude for 30 s to form a W / O emulsion. Inject the W / O emulsion into an aqueous phase containing 2% PVA with 100 times the volume of the bacterial suspension, homogenize and emulsify at 10,000 rpm for 2 min, stir and evaporate the solvent for 4 h, collect the microspheres by centrifugation, wash them 3 times with ultrapure water to remove residual PVA, and freeze-dry at -50 °C for 24 h to obtain the poly(lactic-co-glycolic acid) copolymer loaded with EM composite probiotics.

[0010] Preferably, the composite plant hormone is gibberellin: sodium nitrophenolate: ethephon = 2:1:1.

[0011] Preferably, the preparation method of the EDTA chelated trace metal mixture is as follows: Dissolve EDTA in water with 8 times its weight, add a mixed salt with 2 times the weight of EDTA. The mixed salt is prepared from nickel chloride, copper sulfate, manganese chloride, ferric chloride, and magnesium chloride in a ratio of 1:2:1:3:2. After stirring and dissolving, evaporate to dryness under reduced pressure at 60 °C to obtain it.

[0012] A preparation method of a biomass composite water culture solution includes the following preparation steps:

[0013] (a) Add the straw enzymatic hydrolysate, humic acid, nitrogen-phosphorus-potassium compound fertilizer, silver / carbon microsphere composite bacteriostatic agent, 3 / 5 of the total amount of water, the composite plant hormone, 6 - 9 parts of low-salt soy sauce, β-glucan, 0.05 - 0.1 part of potassium sorbate, and the EDTA chelated trace metal mixture into the reaction kettle in sequence, stir and mix evenly to obtain mixture 1;

[0014] (b) Add 1 / 5 of the remaining water into the reaction flask, add the seaweed extract, and mix evenly to obtain mixture 2;

[0015] (c) Add 1 / 5 of the remaining water into the reaction flask, add glucose, after dissolution, add the poly(lactic-co-glycolic acid) copolymer loaded with EM composite probiotics, and add mixture 2 obtained in step (b), and mix evenly to obtain mixture 3;

[0016] (d) Mix mixture 3 obtained in step (c) and mixture 1 obtained in step (a) evenly to obtain it.

[0017] Beneficial effects:

[0018] 1. The present invention combines calcium carbonate - hydrogen peroxide pretreatment with cellulose complex enzymatic hydrolysis technology to significantly improve the enzymatic hydrolysis efficiency of straw, convert agricultural waste into high - value nutrient solution, reduce raw material costs and environmental pollution.

[0019] 2. Silver / carbon microspheres (nano - silver loaded on carbon - based materials) can inhibit the growth of bacteria and fungi in the hydroponic system through physical adsorption for a long time, reducing root diseases.

[0020] 3. PLGA microspheres prepared by the W / O / W double - emulsion method encapsulate EM composite probiotics to achieve slow release of the bacteria, extend the active period of the probiotics, continuously improve the rhizosphere micro - ecology, promote nutrient absorption, and can prevent the silver / carbon microspheres from killing the probiotics, enabling the co - existence of probiotics and fungicides in one system.

[0021] 4. Gibberellin (promote growth), sodium nitrophenolate (enhance stress resistance), ethephon (regulate ripening) act synergistically in a ratio of 2:1:1 to precisely regulate the physiological requirements of plants at different growth stages, improve yield and quality. EDTA chelates metal ions such as nickel, copper, manganese, iron, and magnesium, improving the stability and bio - availability of trace elements, preventing nutrient deficiency symptoms, and promoting enzyme activity and photosynthesis. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is the SEM image of the silver / carbon microsphere composite bacteriostatic agent of the present invention.

[0023] Figure 2 It is the microscope picture of the PLGA - loaded EM composite probiotic microsphere of the present invention.

[0024] Figure 3 It is the comparison diagram of the growth of peppers cultured in the culture solution of Example 1 and the culture solution of Comparative Example 2 for 20 days of the present invention.

[0025] Figure 4 It is the comparison diagram of the growth of peppers cultured in the culture solution of Example 1 and the culture solution of Comparative Example 4 for 20 days of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0026] To make the technical solution of the present invention clearer, the following further describes the present invention in detail with reference to the accompanying drawings and specific embodiments.

[0027] Example 1

[0028] Raw material preparation:

[0029] Preparation of straw enzymatic hydrolysate: Take 1 kg of corn straw, crush it through a 30-mesh sieve, soak it in a calcium carbonate-hydrogen peroxide mixed aqueous solution with a mass ratio of 9:1 (900 g of calcium carbonate + 100 g of H2O2 + 10 L of water), let it stand at 120 °C for 80 min to obtain straw b. Mix straw b with 9 times deionized water (9 kg), let it stand at 40 °C for 30 min, filter to obtain straw c. Place straw c in an oven at 60 °C and dry it to a constant weight, then sterilize it by high-pressure steam (120 °C, 30 min) to obtain straw d. Add straw d and water at a ratio of 1:10 (100 g of straw d + 1 L of water) to an enzymatic hydrolysis tank (60 °C), adjust the pH to 4.8 with phosphate buffer solution, add a cellulose complex enzyme containing 1% Tween-80 (50 U / g of straw), seal and enzymatically hydrolyze until the COD is stable (about 48 h), centrifuge and take the supernatant to obtain the straw enzymatic hydrolysate.

[0030] Preparation of seaweed extract: Take 500 g of fresh brown algae, rinse it with clean water and dry it at 40 °C, crush it to 20 meshes, mix it with deionized water at a ratio of 1:10 (25 g of powder + 250 g of water), stir and extract at 60 °C for 4 h, centrifuge (4000 rpm, 15 min), and concentrate the supernatant under reduced pressure to a paste.

[0031] Preparation of silver / carbon microsphere composite antibacterial agent: Weigh 10 g of glucose, add 2 g of silver nitrate and dissolve it in 100 g of deionized water, transfer it to a reaction kettle and react at 180 °C for 7 h. After cooling, centrifuge it, wash it with deionized water and ethanol three times in sequence, and dry it at 85 °C for 4 h to obtain a brownish-black powder. The SEM image of the silver / carbon microsphere composite antibacterial agent is shown in the appendix Figure 1 。

[0032] Preparation of PLGA-loaded EM composite probiotic microspheres: Dissolve 1 g of PLGA (15 kDa) in 9 g of ethyl acetate, stir magnetically until transparent. Centrifuge the EM bacterial solution (OD 600 = 1.0) (5000×g, 10 min), resuspend the bacterial cells in PBS (pH 7.4) containing 10% trehalose. Slowly add 1 ml of the bacterial suspension to the PLGA solution, and ultrasonicate (40% amplitude, 30 s) to form a W / O emulsion. Inject the emulsion into 100 ml of an aqueous phase containing 2% PVA, homogenize and emulsify (10000 rpm, 2 min), stir for 4 h to evaporate the solvent, centrifuge (3000×g, 10 min), wash and then freeze-dry to obtain the bacteria-loaded microspheres. The microscope image of the PLGA-loaded EM composite probiotic microspheres is shown in the appendix Figure 2 。

[0033] Preparation of EDTA chelated trace metal mixture: Dissolve 5 g of EDTA in 40 g of water, add 10 g of mixed salts (nickel chloride:copper sulfate:manganese chloride:iron chloride:magnesium chloride = 1:2:1:3:2), stir and dissolve, then evaporate to dryness under reduced pressure at 60 °C, and grind it into powder.

[0034] Preparation of culture medium:

[0035] Prepare according to the following parts by weight (total water volume is 1000 parts):

[0036] Mixture 1:

[0037] 30 parts of straw enzymolysis liquid, 20 parts of humic acid, 3 parts of nitrogen, phosphorus and potassium compound fertilizer (N:P2O5:K2O = 15:15:15), 0.5 part of silver / carbon microsphere composite bacteriostatic agent, 600 parts of water (3 / 5 of the total amount), 0.005 part of compound plant hormone (gibberellin: compound sodium nitrophenolate: ethephon = 2:1:1), 6 parts of low-salt soy sauce, 0.1 part of β-glucan, 0.05 part of potassium sorbate, 0.4 part of EDTA chelated metal mixture. Add the above components to the reaction kettle in sequence and stir mechanically at room temperature (500 rpm, 30 min) until homogeneous.

[0038] Mixture 2:

[0039] 200 parts of water (1 / 5 of the total amount), 5 parts of seaweed extract. After mixing, stir until dissolved.

[0040] Mixture 3:

[0041] 200 parts of water (1 / 5 of the total amount), 10 parts of glucose, 2 parts of poly(lactic-co-glycolic acid)-loaded EM composite probiotics are added to Mixture 2 and stirred and mixed.

[0042] Final culture medium:

[0043] Mix Mixture 3 and Mixture 1 and stir mechanically at room temperature (300 rpm, 20 min) to obtain.

[0044] Example 2

[0045] Raw material preparation:

[0046] Preparation of straw enzymolysis liquid: Take 1 kg of corn straw, crush it through a 30-mesh sieve, soak it in a calcium carbonate-hydrogen peroxide mixed aqueous solution with a mass ratio of 9.5:1 (950 g of calcium carbonate + 100 g of H2O2 + 10 L of water), stand at 125 °C for 75 min to obtain straw b. Mix straw b with 9.5 times deionized water (9.5 kg), stand at 50 °C for 20 min, filter to obtain straw c. Place straw c in an oven at 70 °C and dry to constant weight, sterilize by high-pressure steam (123 °C, 25 min) to obtain straw d. Add straw d and water at a ratio of 1:10 (100 g of straw d + 1 kg of water) to the enzymolysis tank (63 °C), adjust the pH to 5.5 with phosphate buffer solution, add cellulose complex enzyme containing 2% Tween-80 (50 U / g of straw), seal and enzymolyze until the COD is stable (about 48 h), and centrifuge to take the supernatant to obtain the straw enzymolysis liquid.

[0047] Preparation of seaweed extract: Take 500 g of fresh brown algae, rinse with clear water, dry at 40 °C, crush to 60 mesh, mix with deionized water at a ratio of 1:20 (25 g of powder + 500 g of water), stir and extract at 80 °C for 2 h, centrifuge (4000 rpm, 15 min), and concentrate the supernatant under reduced pressure to a paste.

[0048] Preparation of silver / carbon microsphere composite antibacterial agent: Weigh 10 g of glucose, add 2 g of silver nitrate and dissolve in 100 g of deionized water, transfer to a reaction kettle and react at 180 °C for 7 h, cool and then centrifuge, wash with deionized water and ethanol three times in sequence, and dry at 85 °C for 4 h to obtain a brownish-black powder.

[0049] Preparation of PLGA-loaded EM composite probiotic microspheres: Dissolve 1 g of PLGA (15 kDa) in 9 g of ethyl acetate, stir magnetically until transparent, centrifuge the EM bacterial solution (OD 600 =1.0) (5000×g, 10 min), resuspend the bacterial cells in PBS (pH 7.4) containing 10% trehalose, slowly add 1 ml of the bacterial suspension to the PLGA solution, and ultrasonicate (40% amplitude, 30 s) to form a W / O emulsion. Inject the emulsion into 100 ml of an aqueous phase containing 2% PVA, homogenize and emulsify (10000 rpm, 2 min), stir for 4 h to evaporate the solvent, centrifuge (3000×g, 10 min), wash and then freeze-dry to obtain.

[0050] Preparation of EDTA chelated trace metal mixture: Take 5 g of EDTA and dissolve in 40 g of water, add 10 g of mixed salts (nickel chloride: copper sulfate: manganese chloride: iron chloride: magnesium chloride = 1:2:1:3:2), stir to dissolve and then evaporate to dryness under reduced pressure at 60 °C, and grind into powder.

[0051] Preparation of culture medium:

[0052] Prepare according to the following parts by weight (total water volume is 1100 parts):

[0053] Mixture 1:

[0054] 35 parts of straw enzymatic hydrolysate, 22 parts of humic acid, 4 parts of nitrogen, phosphorus and potassium compound fertilizer (N:P2O5:K2O = 15:15:15), 0.6 part of silver / carbon microsphere composite antibacterial agent, 660 parts of water (3 / 5 of the total amount), 0.008 part of composite plant hormone (gibberellin: compound sodium nitrophenolate: ethephon = 2:1:1), 7 parts of low-salt soy sauce, 0.2 part of β-glucan, 0.08 part of potassium sorbate, 0.6 part of EDTA chelated metal mixture. Add the above components to the reaction kettle in sequence and mechanically stir at room temperature (500 rpm, 30 min) until homogeneous.

[0055] Mixture 2:

[0056] 220 parts of water (1 / 5 of the total amount), 6 parts of seaweed extract. Mix and stir until dissolved.

[0057] Mixture 3:

[0058] 220 parts of water (1 / 5 of the total amount), 12 parts of glucose, and 3.5 parts of poly(lactic-co-glycolic acid)-loaded EM composite probiotics were added to Mixture 2 and stirred and mixed.

[0059] Final culture medium:

[0060] Mix Mixture 3 with Mixture 1 and perform mechanical stirring at room temperature (300 rpm, 20 min) to obtain it.

[0061] Example 3

[0062] Raw material preparation:

[0063] Preparation of straw enzymatic hydrolysate: Take 1 kg of corn straw, crush it through a 30-mesh sieve, soak it in a calcium carbonate-hydrogen peroxide mixed aqueous solution with a mass ratio of 10:1 (1000 g of calcium carbonate + 100 g of H2O2 + 10 L of water), let it stand at 130 °C for 70 min to obtain straw b, mix straw b with 10 times deionized water (10 kg), let it stand at 60 °C for 10 min, filter to obtain straw c, place straw c in an 80 °C oven and dry it to a constant weight, sterilize it by high-pressure steam (125 °C, 20 min) to obtain straw d, add straw d and water at a ratio of 1:10 (100 g of straw d + 1 kg of water) to an enzymatic hydrolysis tank (65 °C), adjust the pH to 6.6 with phosphate buffer solution, add a cellulose composite enzyme containing 3% Tween-80 (50 U / g of straw), seal and enzymatically hydrolyze until the COD is stable (about 48 h), and centrifuge to take the supernatant to obtain the straw enzymatic hydrolysate.

[0064] Preparation of seaweed extract: Take 500 g of fresh brown algae, rinse it with clean water and dry it at 60 °C, crush it to 100 meshes, mix it with deionized water at a ratio of 1:30 (25 g of powder + 750 g of water), stir and extract at 100 °C for 1 h, centrifuge (4000 rpm, 15 min), and concentrate the supernatant under reduced pressure to a paste.

[0065] Preparation of silver / carbon microsphere composite antibacterial agent: Weigh 10 g of glucose, add 2 g of silver nitrate and dissolve it in 100 g of deionized water, transfer it to a reaction kettle and react at 180 °C for 7 h, cool and then centrifuge, wash it 3 times with deionized water and ethanol in sequence, and dry it at 85 °C for 4 h to obtain a brownish-black powder.

[0066] Preparation of PLGA-loaded EM composite probiotic microspheres: Dissolve 1 g of PLGA (15 kDa) in 9 g of ethyl acetate, stir magnetically until transparent, EM bacterial liquid (OD 600Centrifuge (5000×g, 10 min) until =1.0, resuspend the cell pellet in PBS (pH 7.4) containing 10% trehalose. Slowly add 1 ml of the cell suspension to the PLGA solution and sonicate (40% amplitude, 30 s) to form a W / O emulsion. Inject the emulsion into 100 ml of the aqueous phase containing 2% PVA and homogenize (10000 rpm, 2 min). Stir for 4 h to evaporate the solvent, centrifuge (3000×g, 10 min), wash, and then freeze-dry to obtain the product.

[0067] Preparation of EDTA chelated trace metal mixture: Dissolve 5 g of EDTA in 40 g of water, add 10 g of mixed salts (nickel chloride: copper sulfate: manganese chloride: iron chloride: magnesium chloride = 1:2:1:3:2), stir to dissolve, then evaporate to dryness under reduced pressure at 60 °C and grind into powder.

[0068] Preparation of culture medium:

[0069] Prepare according to the following weight parts (total water volume is 1200 parts):

[0070] Mixture 1:

[0071] 40 parts of straw enzymatic hydrolysate, 25 parts of humic acid, 5 parts of nitrogen, phosphorus and potassium compound fertilizer (N:P2O5:K2O = 15:15:15), 0.5 part of silver / carbon microsphere composite antibacterial agent, 720 parts of water (3 / 5 of the total amount), 0.01 part of composite plant hormone (gibberellin: compound sodium nitrophenolate: ethephon = 2:1:1), 9 parts of low-salt soy sauce, 0.3 part of β-glucan, 0.1 part of potassium sorbate, 0.8 part of EDTA chelated metal mixture. Add the above components to the reaction kettle in sequence and mechanically stir at room temperature (500 rpm, 30 min) until homogeneous.

[0072] Mixture 2:

[0073] 240 parts of water (1 / 5 of the total amount), 7 parts of seaweed extract. Mix and stir until dissolved.

[0074] Mixture 3:

[0075] 240 parts of water (1 / 5 of the total amount), 15 parts of glucose, 5 parts of poly(lactic-co-glycolic acid) loaded with EM composite probiotics. Add to Mixture 2 and stir to mix.

[0076] Final culture medium:

[0077] Mix Mixture 3 and Mixture 1 and mechanically stir at room temperature (300 rpm, 20 min) to obtain.

[0078] Comparative Example 1

[0079] Same as Example 1, except that the silver / carbon microsphere composite antibacterial agent is not added.

[0080] Comparative Example 2

[0081] Same as Example 1, except that the EM compound probiotics were not subjected to PLGA loading treatment.

[0082] Comparative Example 3

[0083] Same as Example 1, except that EDTA was not added, and a mixed salt of nickel chloride: copper sulfate: manganese chloride: iron chloride: magnesium chloride = 1:2:1:3:2 was directly added.

[0084] Comparative Example 4

[0085] Same as Example 1, except that the composite phytohormone was not added.

[0086] Comparative Example 5

[0087] Same as Example 1, except that the straw was not treated with an aqueous solution of calcium carbonate - hydrogen peroxide.

[0088] The culture solutions prepared in the comparative examples and examples were used to culture pepper seeds respectively, and tests were carried out on them. The survival rate of probiotics and the microbial contamination rate were monitored by microscope: the solution was centrifuged and precipitated to enrich microorganisms, the enriched microorganisms were smeared, stained and observed under the microscope, and the number of microorganisms in the microscope field of view was directly counted; the heavy metal Pb 2+ adsorption rate was measured. A certain amount of solution sample was fixed to a certain volume as the sample to be measured. Using an atomic absorption spectrophotometer, the absorbance of the sample was measured at the characteristic absorption wavelength of lead ions. According to the standard curve method, the relationship between the absorbance and the lead ion concentration was established through a standard solution with a known concentration, so as to calculate the concentration of lead ions in the sample. The adsorption rate calculation formula is: Adsorption rate (%) = (C0 - C e ) / C e × 100%, where C0 is the initial concentration of lead ions in the solution before adsorption, and C e is the residual concentration of lead ions in the solution after adsorption. The results are shown in Table 1 below.

[0089] Table 1 Test results of examples and comparative examples

[0090]

[0091] The difference between Comparative Example 5 and Examples 1 to 3 is that the straw was not treated with an aqueous solution of calcium carbonate - hydrogen peroxide. As a result, the root length of Comparative Example 5 was 8.9 cm after 20 days, while that of Examples 1 to 3 was ≥9.7 cm. The plant height of Comparative Example 5 was 14.6 cm after 30 days, while that of Examples 1 to 3 was ≥17.5 cm. This shows that after treating the straw with an aqueous solution of calcium carbonate - hydrogen peroxide, the nutrients are more abundant, and there are more nutritional components available for plant growth. That is to say, treating the straw with an aqueous solution of calcium carbonate - hydrogen peroxide can significantly improve the enzymatic hydrolysis efficiency of the straw, and the biomass utilization rate available for plant growth is higher; from Examples 1 to 3 and Comparative Example 1, it can be seen that silver / carbon microspheres can long - term inhibit the growth of bacteria and fungi in the hydroponic system, reduce root diseases, and can adsorb certain heavy metal ions; from Examples 1 to 3 and Comparative Example 2, it can be seen that PLGA microspheres prepared by the W / O / W double - emulsion method encapsulate EM compound probiotics, realizing the slow release of the bacteria, prolonging the active period of the probiotics, continuously improving the rhizosphere micro - ecology, promoting nutrient absorption, and can block the killing of probiotics by silver / carbon microspheres, so that the probiotics and fungicides can co - exist in one system; from Examples 1 to 3 and Comparative Example 4, it can be seen that adding compound plant hormones can accurately regulate the physiological requirements of plants at different growth stages, improving yield and quality; from Examples 1 to 3 and Comparative Example 3, it can be seen that EDTA chelates metal ions such as nickel, copper, manganese, iron, and magnesium, improving the stability and bioavailability of trace elements, preventing nutrient deficiency diseases, and promoting enzyme activity and photosynthesis. Among them, the comparison chart of the growth of peppers cultured in the culture solution of Example 1 and Comparative Example 2 for 20 days is shown in Appendix Figure 3 , and the comparison chart of the growth of peppers cultured in the culture solution of Example 1 and Comparative Example 4 for 20 days is shown in Appendix Figure 4 .

[0092] The above - described embodiments only represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several deformations and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims

1. A biomass composite water culture solution, characterized in that, It contains the following components by weight parts: 30 - 40 parts of straw enzymatic hydrolysate, 20 - 25 parts of humic acid, 5 - 7 parts of seaweed extract, 3 - 5 parts of nitrogen, phosphorus and potassium compound fertilizer with N:P2O5:K2O = 15:15:15, 0.5 - 0.7 parts of silver / carbon microsphere composite antibacterial agent, 2 - 5 parts of poly(lactic-co-glycolic acid) loaded EM composite probiotics, 10 - 15 parts of glucose, 1000 - 1200 parts of water, 0.005 - 0.01 parts of composite plant hormone, 6 - 9 parts of low-salt soy sauce, 0.1 - 0.3 parts of β-glucan, 0.05 - 0.1 parts of potassium sorbate, 0.4 - 0.8 parts of EDTA chelated trace metal mixture; The preparation method of the silver / carbon microsphere composite antibacterial agent is as follows: Weigh glucose, add silver nitrate with a weight of 1 / 5 of the glucose and dissolve it in deionized water with a weight 10 times that of the glucose, and transfer it to a reaction kettle. React at 180 °C for 7 h. After the reaction kettle naturally cools to room temperature, wash the product with deionized water and absolute ethanol for several times, and dry it at 85 °C for 4 h to obtain a brown powder, which is the silver / carbon microsphere composite antibacterial agent; The preparation method of the poly(lactic-co-glycolic acid) loaded EM composite probiotics is as follows: Dissolve PLGA with a relative molecular weight of 15 kDa in ethyl acetate with a weight 9 times that of the PLGA, and stir magnetically until completely dissolved. Culture the EM composite probiotics to the logarithmic growth phase, centrifuge to collect the bacterial cells, and resuspend them in a phosphate buffer solution with a pH of 7.4 containing 10% trehalose. Slowly add the bacterial suspension to a PLGA solution with a volume 10 times that of the bacterial suspension, and perform ultrasonic treatment at an amplitude of 40% for 30 s to form a W / O emulsion. Inject the W / O emulsion into an aqueous phase containing 2% PVA with a volume 100 times that of the bacterial suspension volume, homogenize and emulsify at 10000 rpm for 2 min, stir and volatilize the solvent for 4 h, centrifuge to collect the microspheres, wash them 3 times with ultrapure water to remove the residual PVA, and freeze-dry at -50 °C for 24 h to obtain the poly(lactic-co-glycolic acid) loaded EM composite probiotics.

2. The biomass composite water culture solution according to claim 1, wherein The preparation method of the straw enzymatic hydrolysate is as follows: The straw is crushed and screened through a 30-mesh sieve, and then soaked in an aqueous solution of calcium carbonate - hydrogen peroxide with a mass ratio of 9 - 10:

1. After soaking, it is left standing at 120 - 130 °C for 70 - 80 min to obtain straw b. Then, straw b is added to deionized water with a weight 9 - 10 times that of straw b, and left standing at 40 - 60 °C for 10 - 30 min to obtain straw c. Straw c is placed in an oven at 60 - 80 °C and dried to a constant weight, and then subjected to high-pressure steam sterilization treatment at 120 - 125 °C for 20 - 30 min to obtain straw d; Straw d and water are fed into an enzymatic hydrolysis tank at 60 - 65 °C according to a mass ratio of 1:

10. After stirring evenly, a 1% sodium dihydrogen phosphate buffer aqueous solution is added to the enzymatic hydrolysis raw material to adjust the pH value to 4.8 - 6.

6. Then, a cellulose complex enzyme containing 1% - 3% surfactant is added to the enzymatic hydrolysis tank in a sealed state. The cellulose complex enzyme is composed of endo - cellulase, exo - cellulase, and cellobiase with a mass ratio of 1:1:

2. After the COD of the enzymatic hydrolysis product in the enzymatic hydrolysis tank no longer changes, the enzymatic hydrolysis reaction ends to obtain the straw enzymatic hydrolysate.

3. The biomass composite water culture solution according to claim 1, characterized in that, The preparation method of the seaweed extract is as follows: Fresh seaweed is rinsed with clean water to remove sediment, salt, and epiphytic biological impurities, and dried at a low temperature of 40 - 60 °C. The dried seaweed is ground into a powder with a mesh size of 20 - 100 by a pulverizer. The seaweed powder and deionized water are mixed in a ratio of 1:10 - 1:30 and heated to 60 - 100 °C, and stirred and extracted for 1 - 4 h. The residue is removed by centrifugation, and the supernatant is collected and the water is removed by reduced pressure evaporation to obtain it.

4. The biomass composite water culture solution according to claim 1, characterized in that, The compound plant hormone is gibberellin: sodium nitrophenolate: ethephon = 2:1:

1.

5. The biomass composite water culture solution according to claim 1, characterized in that, The preparation method of the EDTA chelated trace metal mixture is as follows: EDTA is dissolved in water with a weight 8 times that of EDTA, and a mixed salt with a weight 2 times that of EDTA is added. The mixed salt is prepared from nickel chloride, copper sulfate, manganese chloride, iron chloride, and magnesium chloride according to a ratio of 1:2:1:3:

2. After stirring and dissolving, it is evaporated to dryness at 60 °C under reduced pressure to obtain it.

6. A preparation method of the biomass composite water culture solution according to any one of claims 1-5, characterized in that, It includes the following preparation steps: (a) The straw enzymatic hydrolysate, humic acid, nitrogen - phosphorus - potassium compound fertilizer, silver / carbon microsphere composite antibacterial agent, 3 / 5 of the total amount of water, compound plant hormone, 6 - 9 parts of low - salt soy sauce, β - glucan, 0.05 - 0.1 part of potassium sorbate, and EDTA chelated trace metal mixture are added to the reaction kettle in sequence, and stirred and mixed evenly to obtain mixture 1; (b) 1 / 5 of the remaining water is added to the reaction flask, and the seaweed extract is added and mixed evenly to obtain mixture 2; (c) 1 / 5 of the remaining water is added to the reaction flask, glucose is added, and after dissolution, poly(lactic - co - glycolic acid) - loaded EM composite probiotics are added, and mixture 2 obtained in step (b) is added and mixed evenly to obtain mixture 3; (d) Mixture 3 obtained in step (c) and mixture 1 obtained in step (a) are mixed evenly to obtain it.

Images