Synthetic organic nutrient solution based on animal keratin cracked small peptide

Abstract

The invention discloses a synthetic organic nutrient solution based on animal keratin cleavage small peptide, and particularly relates to the technical field of agricultural biologication.The synthetic organic nutrient solution is specifically prepared from a 200-1500 Da small peptide component obtained by directional cleavage from animal keratin through a composite enzymolysis stepped temperature control technology; the plant essential nutrient elements are synergistically stable with the organic acid chelating agent; the triple biological activation system is composed of alginate oligosaccharide, auxin and defense signal molecules; and a space stable structure is formed by xanthan gum-sodium alginate composite colloid. Keratinase and cysteine protease are used for cooperatively breaking a disulfide bond network, and active peptide fragments are enriched through ultrafiltration and grading; component precipitation failure is prevented through organic acid chelation and a colloid three-dimensional network; and integrating biological signal molecules to synchronously activate crop growth and stress resistance pathways. According to the invention, high-valued conversion of waste keratin resources is realized, and the total-effect organic nutrient solution with nutrition delivery, physiological regulation and system resistance induction functions is formed.

Description

Technical Field

[0001] This invention relates to the field of agricultural biotechnology, and more specifically, to a synthetic organic nutrient solution based on small peptides derived from animal keratin cleavage. Background Art

[0002] With the rapid development of organic agriculture, traditional chemical fertilizers are increasingly restricted due to their environmental pollution, soil compaction, and declining quality of agricultural products. Developing highly efficient and environmentally friendly biostimulants has become an important direction for global agricultural technology. Animal keratin, a waste resource from the slaughtering and leather industries, has a global annual production exceeding ten million tons. Its rich cysteine ​​content (12%-18%) and hydrophobic amino acids constitute a unique molecular structure, theoretically capable of being converted into high-value small peptide nutrient solutions. However, due to the highly cross-linked disulfide network and stable helical conformation of keratin, conventional hydrolysis techniques struggle to achieve targeted cleavage, leading to problems such as uncontrollable active ingredients and low plant absorption rates in existing animal protein fertilizers. Therefore, there is an urgent need to develop a keratin resource utilization solution based on enzyme engineering and molecular screening technologies to convert waste keratin into small peptide nutrient preparations with defined molecular weight ranges and biological functions, thus solving agricultural pollution problems while achieving high-value utilization of waste resources.

[0003] Current keratin resource utilization technologies face three major bottlenecks: First, while chemical hydrolysis (such as the strong alkali and high-temperature treatment used in patent CN108424276A) can break disulfide bonds, it leads to amino acid racemization and the production of toxic substances. The resulting product has a molecular weight >5000 Da, and the plant absorption rate is less than 15%. Second, single enzymatic hydrolysis processes (such as the use of keratinase in patent JP2020152000A) cannot completely deconstruct the keratin crystal domains, resulting in a hydrolysis degree of only 40%-60%, and the proportion of functional small peptides in the product is <30%. Third, there are design flaws in the end products. Existing protein fertilizers often directly mix inorganic nutrients (such as CN112159329A), lacking a chelation stabilization system. Metal ions combine with small peptides to produce precipitation, reducing bioavailability by more than 40%. More importantly, existing technologies have not established a molecular weight-bioactivity correlation mechanism, have not identified characteristic growth-promoting peptides (such as KVLPVP), and cannot achieve precise regulation of crop physiological responses.

[0004] Therefore, a synthetic organic nutrient solution based on animal keratin cleavage peptides is proposed to address the above problems. Summary of the Invention

[0005] In order to overcome the above-mentioned defects of the prior art, embodiments of the present invention provide a synthetic organic nutrient solution based on animal keratin cleavage peptides to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a synthetic organic nutrient solution based on animal keratin cleavage peptides, comprising the following components: a water-soluble peptide mixture obtained by directional enzymatic hydrolysis of animal-derived keratin, the molecular weight of which is controlled within the range of 200-1500 Da and accounts for 0.1%-10% of the total component mass; essential plant nutrients including at least three of the macroelements of nitrogen, phosphorus, and potassium and the microelements of iron, zinc, and boron, with a total concentration range of 0.5-20 g / L; an organic acid chelating agent selected from one or more of citric acid, humic acid, or amino acids, with a concentration range of 0.05-5 g / L; a bioactive additive including at least one of seaweed extract, plant growth hormone, or beneficial microbial metabolites, with a concentration range of 0.01-2 g / L; and the remainder being an aqueous solvent, wherein each component forms a stable colloidal dispersion system through a specific preparation process.

[0007] Preferably, the keratin cleavage peptides are prepared by the following process: using animal hair or hooves as raw materials, the hair or hooves are defatted in a 1%-5% sodium carbonate solution at 60-80°C for 30-90 minutes, and then pulverized into particles with a diameter ≤1mm; in a buffer system with pH 7.0-9.0, a complex enzyme system composed of keratinase and cysteine ​​protease is used for stepwise temperature-controlled hydrolysis at 45-60°C, wherein the initial 2 hours are maintained at 45-50°C to promote substrate swelling, and the temperature is increased to 55-60°C for the next 3-6 hours to accelerate peptide bond cleavage; after hydrolysis, the large molecular weight proteins are removed by separation through an ultrafiltration membrane with a molecular weight cutoff of 1500Da, and the target small peptide components are enriched by reverse ultrafiltration with a molecular weight cutoff of 200Da.

[0008] Preferably, in the compound enzymatic hydrolysis process, the ratio of active units of keratinase to cysteine ​​protease is (2-5):1, and the total enzyme addition is 0.5%-3% of the substrate dry weight; 0.1%-0.5% sodium sulfite is added to the enzymatic hydrolysis system as a disulfide bond cleavage promoter, and a segmented temperature control strategy is adopted: the first stage is maintained at 50±2℃ for 90-120 minutes to unwind the keratin helix structure, and the second stage is maintained at 58±2℃ for 180-240 minutes to achieve deep cleavage of peptide chains, with a final degree of hydrolysis ≥85% and free amino acid content ≤15%.

[0009] Preferably, the small peptide mixture contains at least 18 free amino acids, wherein the total mass percentage of sulfur-containing amino acids cystine and methionine is ≥8%, the total mass percentage of aromatic amino acids phenylalanine and tyrosine is ≥5%, and the essential amino acid index (EAAI) is ≥0.85; the sum of the mass fractions of dipeptides and tripeptides in the small peptide component is ≥60%, and it contains characteristic growth-promoting peptides KVLPVP and EAPAPK.

[0010] Preferably, the essential nutrients for plants are composed of the following: nitrogen source is selected from urea or ammonium nitrate, with a concentration of 2-10 g / L; phosphorus source is potassium dihydrogen phosphate, with a concentration of 1-5 g / L; potassium source is potassium sulfate, with a concentration of 1.5-8 g / L; and trace elements are in the form of EDTA chelates, wherein the concentration of chelated iron (Fe-EDTA) is 50-200 mg / L, the concentration of chelated zinc (Zn-EDTA) is 20-100 mg / L, and the concentration of boric acid is 5-50 mg / L, and the mass ratio of nitrogen, phosphorus, and potassium elements satisfies N:P2O5:K2O=(1.5-3):1:(1.2-2.5).

[0011] Preferably, the bioactive additive is a compound system of fucoidan oligosaccharide and plant growth regulator, wherein the fucoidan oligosaccharide has a molecular weight of 800-3000 Da, is extracted from Sargassum fusiforme or Sargassum fusiforme, and has a concentration of 0.5-1.5 g / L; the plant growth regulator contains 0.01-0.1 g / L of indolebutyric acid (IBA) and 0.005-0.05 g / L of methyl jasmonate (MeJA), which together with the fucoidan oligosaccharide form a triple stress response activation system.

[0012] Preferably, the above-mentioned nutrient solution further includes a penetration enhancer with a mass concentration of 0.01-0.5 g / L and a stabilizer with a mass concentration of 0.1-1 g / L; the penetration enhancer is selected from sorbitol or polyglycerol fatty acid ester; the stabilizer is a composite colloid composed of xanthan gum and sodium alginate in a mass ratio of (1:2)-(1:3), which forms a three-dimensional network structure in the nutrient solution to prevent the components from settling.

[0013] A method for preparing an organic nutrient solution includes the following steps: mixing keratin cleavage peptides with an organic acid chelating agent at 40-50℃ for 30-60 minutes to form a peptide-chelating agent complex; cooling to 25-30℃ and adding a dissolved solution of essential plant nutrients, controlling the addition rate to ≤5L / min to prevent local supersaturation; finally adding bioactive additives and stabilizers, homogenizing at 2000-5000rpm for 3-5 minutes, adjusting the pH to 5.5-6.5 with citric acid and maintaining stirring for 30 minutes for maturation.

[0014] An organic nutrient solution is applied in agricultural production for any of the following scenarios: during crop transplanting, drenching the roots with a 200-300 times diluted solution promotes the development of fine roots and increases root vitality by more than 10%; during flowering and fruit setting, foliar spraying with a 300-500 times diluted solution increases the fruit setting rate by 12%-18%; before abiotic stress, spraying with a 150-250 times diluted solution induces systemic resistance in crops, reducing malondialdehyde (MDA) content by more than 25%.

[0015] A plant cultivation system integrates the aforementioned nutrient solution and intelligent application device: the nutrient solution storage tank is connected to the main irrigation pipeline via a proportional valve, and the conductivity (control range 1.2-2.8 mS / cm) and pH value (control range 5.8-6.2) of the nutrient solution are monitored in real time by an EC / pH sensor; the application program is set to drip irrigation once a week during the seedling stage (dilution ratio 300±50), and foliar spraying once every 5 days during the reproductive growth stage (dilution ratio 400±50), while the system records crop growth parameters and dynamically adjusts the application plan through an Internet of Things platform.

[0016] The technical effects and advantages of this invention are as follows:

[0017] Compared to existing technologies, this invention constructs a complex enzymatic hydrolysis system of keratinase and cysteine ​​protease, combined with stepwise temperature control and sodium sulfite-assisted reduction technology, to effectively deconstruct the disulfide bond cross-linking network of keratin, achieving efficient and targeted cleavage of keratin resources. Ultrafiltration membrane fractionation technology is used to precisely retain small peptide components in the 200-1500 Da molecular weight range, ensuring the product is rich in dipeptides / tripeptides with transmembrane transport capabilities and characteristic growth-promoting peptides. Innovatively, organic acid chelating agents and composite colloidal stabilizers work synergistically to form a steric hindrance effect and charge stabilization mechanism, preventing metal ion precipitation and active ingredient inactivation in the nutrient solution. The invention integrates the triple bioactivation functions of fucoidan, plant growth hormones, and defense signaling molecules, synergistically regulating crop root development and stress resistance gene expression through signaling pathways. This technology system achieves breakthroughs at three levels: molecular cleavage control, component stabilization design, and biofunctional integration, ultimately obtaining a comprehensive organic nutrient solution that combines nutrient supply, physiological regulation, and environmental adaptability. Attached Figure Description

[0018] Figure 1 This is a flowchart of the process of the present invention.

[0019] Figure 2 This is a diagram of the overall framework structure of the present invention. Detailed Implementation

[0020] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0021] Example 1

[0022] As attached Figure 1-2As shown, (1) a synthetic organic nutrient solution based on animal keratin cleavage peptides, comprising the following components: a mixture of water-soluble peptides obtained by directional enzymatic hydrolysis of animal-derived keratin, the molecular weight of which is controlled within the range of 200-1500 Da and accounts for 0.1%-10% of the total component mass; plant essential nutrients including at least three of the macroelements of nitrogen, phosphorus, and potassium and the microelements of iron, zinc, and boron, with a total concentration range of 0.5-20 g / L; an organic acid chelating agent selected from one or more of citric acid, humic acid, or amino acids, with a concentration range of 0.05-5 g / L; a bioactive additive including at least one of seaweed extract, plant growth hormone, or beneficial microbial metabolites, with a concentration range of 0.01-2 g / L; the remainder being a water solvent, wherein each component is obtained by... A specific preparation process forms a stable colloidal dispersion system. Using bovine and ovine hooves as raw materials, keratin peptides with a molecular weight of 200-1500 Da are obtained through degreasing, pulverization, and enzymatic hydrolysis. These peptides are added to the nutrient solution system at 3% of their total mass. Essential plant nutrients include urea (6 g / L), potassium dihydrogen phosphate (3 g / L), potassium sulfate (5 g / L), EDTA-chelated iron (100 mg / L), and boric acid (30 mg / L). The organic acid chelating agent is a combination of citric acid (2 g / L) and humic acid (1 g / L). Bioactive additives include brown alginic oligosaccharides (1 g / L) and indolebutyric acid (0.05 g / L) extracted from Sargassum. Finally, a colloidal dispersion system is constructed using xanthan gum-sodium alginate composite colloid (0.2 g / L), with water added to a final volume of 1.

[0023] (2) The keratin cleavage peptides are prepared by the following process: animal hair or hooves are used as raw materials, and after defatting in a 1%-5% sodium carbonate solution at 60-80℃ for 30-90 minutes, they are pulverized to particles with a diameter ≤1mm; in a buffer system of pH 7.0-9.0, a complex enzyme system composed of keratinase and cysteine ​​protease is used for stepwise temperature-controlled hydrolysis at 45-60℃, wherein the initial 2 hours are kept at 45-50℃ to promote substrate swelling, and the temperature is increased to 55-60℃ for the next 3-6 hours to accelerate peptide bond cleavage; after hydrolysis, the large molecular weight proteins are removed by ultrafiltration membrane with a molecular weight cutoff of 1500Da, and the target small peptide components are enriched by reverse ultrafiltration with a molecular weight cutoff of 200Da. Among them, 1kg of bovine and ovine hoof and horn powder (particle size ≤0.8mm) is defatted in a 3% sodium carbonate solution at 75℃ for 60 minutes; then transferred to a pH 7.0-9.0 buffer system. An 8.0 phosphate buffer system was used, with the addition of a complex enzyme system consisting of keratinase (200,000 U) and cysteine ​​protease (80,000 U). The first stage of hydrolysis was carried out at 48°C for 120 minutes to unwind the keratin helix, and the second stage of hydrolysis was carried out at 58°C for 240 minutes to deeply cleave the peptide chain. The hydrolysate was then passed through an ultrafiltration membrane with a molecular weight cutoff of 1500 Da to remove macromolecular impurities, and then through a reverse ultrafiltration membrane with a molecular weight cutoff of 200 Da to enrich the target small peptide components, finally obtaining a small peptide concentrate with a solid content of 15%.

[0024] (3) In the aforementioned enzymatic hydrolysis process, the ratio of active units of keratinase to cysteine ​​protease is (2-5):1, and the total enzyme addition is 0.5%-3% of the substrate dry weight; 0.1%-0.5% sodium sulfite is added to the enzymatic hydrolysis system as a disulfide bond cleavage promoter, and a segmented temperature control strategy is adopted: the first stage is maintained at 50±2℃ for 90-120 minutes to unwind the keratin helix structure, and the second stage is maintained at 58±2℃ for 180-240 minutes to achieve deep peptide chain cleavage. The final degree of hydrolysis was ≥85% and the free amino acid content was ≤15%. During the enzymatic hydrolysis process, 0.3% sodium sulfite was added to the system to assist in the cleavage of disulfide bonds. The ratio of keratinase to cysteine ​​protease activity units was controlled at 3:1, and the total enzyme addition was 1.8% of the substrate dry weight. The reaction was terminated when the degree of hydrolysis reached 87.5% and the free amino acid content was 12.3%. The obtained small peptide components were analyzed by HPLC, and the proportion of molecular weight in the range of 200-1500 Da was 91.5%.

[0025] (4) The small peptide mixture contains at least 18 free amino acids, of which the total mass percentage of sulfur-containing amino acids cystine and methionine is ≥8%, the total mass percentage of aromatic amino acids phenylalanine and tyrosine is ≥5%, and the essential amino acid index (EAAI) is ≥0.85; the sum of the mass fractions of dipeptides and tripeptides in the small peptide components is ≥60%, and it contains characteristic growth-promoting peptides KVLPVP and EAPAPK. The small peptides prepared above are detected by an amino acid analyzer and contain 19 free amino acids, of which the total mass percentage of cystine + methionine is 9.2%, and the total mass percentage of phenylalanine + tyrosine is 6.1%; the characteristic growth-promoting peptides KVLPVP (m / z 668.4) and EAPAPK (m / z 628.3) are identified by mass spectrometry; the ultrafiltration concentrate is determined by gel chromatography and the total mass percentage of dipeptides and tripeptides is 68.5%, and the essential amino acid index (EAAI) is 0.88.

[0026] (5) The specific composition of the essential plant nutrients is as follows: the nitrogen source is selected from urea or ammonium nitrate, with a concentration of 2-10 g / L; the phosphorus source is potassium dihydrogen phosphate, with a concentration of 1-5 g / L; the potassium source is potassium sulfate, with a concentration of 1.5-8 g / L; the trace elements are in the form of EDTA chelate, of which the concentration of chelated iron (Fe-EDTA) is 50-200 mg / L, the concentration of chelated zinc (Zn-EDTA) is 20-100 mg / L, and the concentration of boric acid is 5-50 mg / L, and the mass ratio of nitrogen, phosphorus and potassium elements satisfies N:P2O5:K2O=(1.5-3):1:(1.2-2.5), wherein the essential plant nutrients are prepared according to N:P2O5:K2O=2.5:1:1.8: the nitrogen source is provided by urea (pure N 6.2 g / L), the phosphorus source is potassium dihydrogen phosphate (P2O5 2.5 g / L), and the potassium source is potassium sulfate (K2O5 2.5 g / L). 4.5 g / L); trace elements are Fe-EDTA (120 mg / L), Zn-EDTA (50 mg / L), and boric acid (35 mg / L), which are chelated with citric acid to form a stable complex.

[0027] (6) The bioactive additive is a compound system of fucoidan oligosaccharide and plant growth regulator, wherein the fucoidan oligosaccharide has a molecular weight of 800-3000 Da, is extracted from *Sargassum fusiforme* or *Sargassum fusiforme*, and has a concentration of 0.5-1.5 g / L; the plant growth regulator contains 0.01-0.1 g / L of indolebutyric acid (IBA) and 0.005-0.05 g / L of methyl jasmonate (MeJA), which together with the fucoidan oligosaccharide constitute a triple stress response activation system, wherein the bioactivation system consists of fucoidan oligosaccharide with a molecular weight of 1500 Da (0.8 g / L), indolebutyric acid IBA (0.08 g / L) and methyl jasmonate MeJA (0.03 g / L); wherein the fucoidan oligosaccharide is extracted from *Sargassum fusiforme* and obtained by degradation by β-glucanase; the three are compounded in a mass ratio of 26.7:2.7:1, and simultaneously activate the auxin signaling pathway and the JA defense pathway through leaf absorption.

[0028] (7) It also contains a penetration enhancer with a mass concentration of 0.01-0.5 g / L and a stabilizer with a mass concentration of 0.1-1 g / L; the penetration enhancer is selected from sorbitol or polyglycerol fatty acid ester; the stabilizer is a composite colloid composed of xanthan gum and sodium alginate in a mass ratio of (1:2)-(1:3), which forms a three-dimensional network structure in the nutrient solution to prevent component sedimentation. Among them, 0.3 g / L of polyglycerol fatty acid ester is added as a penetration enhancer to enhance the leaf surface adhesion ability; the stabilizer is a mixture of xanthan gum and sodium alginate in a mass ratio of 1:2.5 (total concentration 0.5 g / L), which is used at a shear rate of 100 s. -1 A three-dimensional network structure with a viscosity of 450 cP was formed, and no component stratification was observed after centrifugation (4000 rpm × 10 min).

[0029] (8) A method for preparing an organic nutrient solution, comprising the following steps: mixing keratin cleavage peptides with an organic acid chelating agent at 40-50°C for 30-60 minutes to form a peptide-chelating agent complex; cooling to 25-30°C and adding a dissolved solution of essential plant nutrients, controlling the addition rate to ≤5L / min to prevent local oversaturation; finally adding bioactive additives and stabilizers, homogenizing at 2000-5000 rpm for 3-5 minutes, adjusting the pH to 5.5-6.5 with citric acid and maintaining stirring for 30 minutes for maturation, wherein the keratin peptide concentrate is mixed with citric acid / humic acid at 45°C and stirred for 45 minutes; cooling to 28°C and adding a pre-dissolved nutrient solution at a uniform rate (4L / min); finally adding a mixture of brown algae oligosaccharide-IBA-MeJA and xanthan gum-sodium alginate colloid, homogenizing at 5000 rpm for 4 minutes; adjusting the pH to 6.0 with citric acid, maintaining maturation for 30 minutes, and then filling.

[0030] (9) An application of an organic nutrient solution in agricultural production, used in any of the following scenarios: during crop transplanting, irrigating the roots with a 200-300 times diluted solution promotes the development of capillary roots and increases root vitality by more than 10%; during flowering and fruit setting, foliar spraying with a 300-500 times diluted solution increases the fruit setting rate by 12%-18%; before abiotic stress, spraying with a 150-250 times diluted solution induces systemic resistance in crops, reducing malondialdehyde (MDA) content by more than 25%, of which, during tomato transplanting, irrigating the roots with a 250 times diluted solution at 500 mL / plant each time increases the fresh weight of the roots by 12%; during flowering, foliar spraying with a 400 times diluted solution increases the fruit setting rate by 16%; and spraying with a 200 times diluted solution 7 days before high temperature stress reduces the MDA content in the leaves by 30%.

[0031] (10) A plant cultivation system integrating the nutrient solution and intelligent application device described in claims 1-7: the nutrient solution storage tank is connected to the main irrigation pipeline through a proportional valve, and the conductivity (control range 1.2-2.8 mS / cm) and pH value (control range 5.8-6.2) of the nutrient solution are monitored in real time by an EC / pH sensor; the application program is set to drip irrigation once a week during the seedling stage (dilution ratio 300±50), and foliar spraying once every 5 days during the reproductive growth stage (dilution ratio 400±50), while the crop growth parameters are recorded and the application plan is dynamically adjusted through an Internet of Things platform, wherein the nutrient solution stock solution is injected into the intelligent storage tank, and the dilution module is interlocked and controlled by an EC sensor (set threshold 2.5 mS / cm) and a pH sensor (set threshold 6.0); the seedling stage program is set to drip irrigation once a week (automatic dilution 300 times), and foliar spraying once every 5 days during the flowering stage (automatic dilution 450 times); the cloud system receives crop growth sensor data and dynamically adjusts the irrigation frequency and dilution ratio.

[0032] Example 2: Multi-source data joint modeling environment (500L scale nutrient solution production and application)

[0033] Step 1: Raw material pretreatment and enzymatic hydrolysis

[0034] Take 100 kg of bovine and ovine hoof and horn raw materials (containing ≥85% keratin) and put them into a defatting tank containing 3 wt% sodium carbonate. Treat at 75±2℃ for 60 minutes to remove lipids. After washing with water until neutral, process with an ultra-micro pulverizer to an average particle size of 0.8 mm. Put the pulverized material into a 2000L enzymatic hydrolysis tank and add pH 8.0 phosphate buffer to a total volume of 800L. Add keratinase (20 million U) and cysteine ​​protease (7 million U) to achieve an enzyme activity ratio of 2.86:1. Add 0.3 wt% sodium sulfite simultaneously. Start the step temperature control program: the first stage is maintained at 48±0.5℃ for 120 minutes to unwind the α-helix of keratin. The second stage is heated to 58±0.5℃ for 240 minutes for hydrolysis. During this period, the pH is automatically maintained at 7.8-8.2 with alkaline solution. The degree of hydrolysis reaches 88.2% as determined by the ninhydrin method at the end of the hydrolysis.

[0035] Step 2: Small peptide isolation and enrichment

[0036] After removing residues by plate and frame filtration, the enzymatic hydrolysate was introduced into an ultrafiltration system (polyethersulfone membrane, operating pressure 0.4 MPa) with a molecular weight cutoff of 1500 Da, and the permeate was collected. It was then concentrated 5 times by a reverse ultrafiltration membrane (operating pressure 0.6 MPa) with a molecular weight cutoff of 200 Da to obtain 120 L of active peptide concentrate with a molecular weight of 200-1500 Da (solid content 16.3%). HPLC analysis (C18 column, acetonitrile-water gradient elution) showed that the dipeptide / tripeptide ratio was 69.7%, and the characteristic peptides KVLPVP (retention time 9.8 min) and EAPAPK (retention time 11.2 min) were confirmed by mass spectrometry.

[0037] Step 3: Nutrient Chelation

[0038] Add the following ingredients sequentially to the 500L mixing tank:

[0039] Keratin peptide concentrate (dry weight 19.6 kg);

[0040] 8 kg of citric acid + 4 kg of humic acid (dissolve by stirring at 45°C);

[0041] The mixture was kept warm and stirred for 45 minutes to form a peptide-organic acid complex. After cooling to 28°C, a premixed nutrient solution (300L of deionized water containing 62kg urea, 25kg potassium dihydrogen phosphate, 45kg potassium sulfate, 1.2kg Fe-EDTA, and 0.35kg boric acid) was added at a uniform rate (10L / min).

[0042] Step 4: Construction of bioactive system

[0043] Brown algae oligosaccharide (extracted from 1 kg of *Alternaria solani*, and hydrolyzed by β-glucanase to obtain 40 L of oligosaccharide solution with a molecular weight of 1520 Da), 0.8 kg of indolebutyric acid, and 0.3 kg of methyl jasmonic acid were premixed and added to the mixing tank; simultaneously, a stabilizer solution (1 kg of xanthan gum + 2.5 kg of sodium alginate pre-dissolved at 60℃) was added, and water was added to bring the volume to 500 L.

[0044] Step 5: Homogenization, Maturation, and Filling

[0045] The mixture was homogenized at 5000 rpm for 5 minutes using a high-shear homogenizer, and the pH was adjusted to 6.05 with food-grade citric acid. It was then transferred to a maturation tank and stirred at 30 rpm for 30 minutes. The viscosity was monitored in real time and stabilized at 455 cP (25℃, Brookfield DV2T viscometer). Finally, it was sterilized by a 0.22 μm microfiltration membrane and then filled into bottles. The resulting nutrient solution had a conductivity of 2.53 mS / cm and showed no precipitation after standing at room temperature for 30 days.

[0046] Step 6: Field Application Validation

[0047] Implemented at a tomato planting base (Shouguang, Shandong):

[0048] Transplanting period: Dilute 250 times (EC=1.01mS / cm) and drip irrigate, 500mL / plant each time. After 3 times, the fresh weight of the root system increased by 13% compared with the control group.

[0049] Flowering period: Foliar spraying with a 400-fold dilution (droplet size 50-80μm) increases fruit set rate by 16%;

[0050] High temperature stress: Spraying with a 200-fold diluted solution before the temperature reaches 37℃ for an extended period reduced the MDA content in leaves by 26%.

[0051] Meanwhile, the application frequency is automatically adjusted through the intelligent irrigation system (EC sensor threshold 1.8±0.2mS / cm), saving 32% of water.

[0052] Finally, a few points should be explained: First, in the description of this application, it should be noted that, unless otherwise specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense, and may refer to mechanical or electrical connections, internal communication between two components, or direct connection. "Up," "down," "left," and "right" are only used to indicate relative positional relationships. When the absolute positions of the objects being described change, the relative positional relationships may also change.

[0053] Secondly: The drawings of the embodiments disclosed in the present invention only involve structures related to the embodiments disclosed in the present invention. Other structures may refer to conventional designs. The same embodiment and different embodiments of the present invention may be combined with each other without conflict.

[0054] Finally: The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A synthetic organic nutrient solution based on animal keratin cleavage peptides, characterized in that... It comprises the following components: a mixture of water-soluble small peptides obtained by targeted enzymatic hydrolysis of animal-derived keratin, with a molecular weight controlled in the range of 200-1500 Da and accounting for 0.1%-10% of the total component mass; essential plant nutrients including at least three of the macroelements of nitrogen, phosphorus, and potassium and the microelements of iron, zinc, and boron, with a total concentration range of 0.5-20 g / L; an organic acid chelating agent selected from one or more of citric acid, humic acid, or amino acids, with a concentration range of 0.05-5 g / L; a bioactive additive including at least one of seaweed extract, plant growth hormone, or beneficial microbial metabolites, with a concentration range of 0.01-2 g / L; and the remainder being an aqueous solvent, wherein each component forms a stable colloidal dispersion system through a specific preparation process.

2. The synthetic organic nutrient solution based on animal keratin cleavage peptides according to claim 1, characterized in that... The keratin cleavage peptides are prepared by the following process: animal hair or hooves are used as raw materials, and after defatting in a 1%-5% sodium carbonate solution at 60-80℃ for 30-90 minutes, they are pulverized into particles with a diameter ≤1mm; in a buffer system with pH 7.0-9.0, a complex enzyme system composed of keratinase and cysteine ​​protease is used for stepwise temperature-controlled hydrolysis at 45-60℃, wherein the initial 2 hours are kept at 45-50℃ to promote substrate swelling, and the temperature is increased to 55-60℃ for the next 3-6 hours to accelerate peptide bond cleavage; after hydrolysis, the large molecular weight proteins are removed by separation through an ultrafiltration membrane with a molecular weight cutoff of 1500Da, and the target small peptide components are enriched by reverse ultrafiltration with a molecular weight cutoff of 200Da.

3. The synthetic organic nutrient solution based on animal keratin cleavage peptides according to claim 2, characterized in that... In the aforementioned enzymatic hydrolysis process, the ratio of active units of keratinase to cysteine ​​protease is (2-5):1, and the total enzyme addition is 0.5%-3% of the substrate dry weight. Sodium sulfite (0.1%-0.5% by mass) is added to the hydrolysis system as a disulfide bond cleavage promoter, and a segmented temperature control strategy is adopted: the first stage is maintained at 50±2℃ for 90-120 minutes to unwind the keratin helix structure; the second stage is maintained at 58±2℃ for 180-240 minutes to achieve deep peptide chain cleavage, ultimately achieving a degree of hydrolysis ≥85% and a free amino acid content ≤15%.

4. The synthetic organic nutrient solution based on animal keratin cleavage peptides according to claim 1, characterized in that... The small peptide mixture contains at least 18 free amino acids, of which the total mass percentage of sulfur-containing amino acids cystine and methionine is ≥8%, the total mass percentage of aromatic amino acids phenylalanine and tyrosine is ≥5%, and the essential amino acid index (EAAI) is ≥0.85; the sum of the mass fractions of dipeptides and tripeptides in the small peptide components is ≥60%, and it contains characteristic growth-promoting peptides KVLPVP and EAPAPK.

5. The synthetic organic nutrient solution based on animal keratin cleavage peptides according to claim 1, characterized in that... The specific composition of the essential nutrients for plants is as follows: nitrogen source is selected from urea or ammonium nitrate, with a concentration of 2-10 g / L; phosphorus source is potassium dihydrogen phosphate, with a concentration of 1-5 g / L; potassium source is potassium sulfate, with a concentration of 1.5-8 g / L; trace elements are in the form of EDTA chelate, of which chelated iron (Fe-EDTA) has a concentration of 50-200 mg / L, chelated zinc (Zn-EDTA) has a concentration of 20-100 mg / L, and boric acid has a concentration of 5-50 mg / L, and the mass ratio of nitrogen, phosphorus and potassium elements satisfies N:P2O5:K2O=(1.5-3):1:(1.2-2.5).

6. The synthetic organic nutrient solution based on animal keratin cleavage peptides according to claim 1, characterized in that... The bioactive additive is a compound system of fucoidan oligosaccharide and plant growth regulator. The fucoidan oligosaccharide has a molecular weight of 800-3000 Da, is extracted from Sargassum fusiforme or Sargassum fusiforme, and has a concentration of 0.5-1.5 g / L. The plant growth regulator contains 0.01-0.1 g / L of indolebutyric acid (IBA) and 0.005-0.05 g / L of methyl jasmonate (MeJA). The two, together with the fucoidan oligosaccharide, form a triple stress response activation system.

7. The synthetic organic nutrient solution based on animal keratin cleavage peptides according to claim 1, characterized in that... It also contains a penetration enhancer at a mass concentration of 0.01-0.5 g / L and a stabilizer at a mass concentration of 0.1-1 g / L; the penetration enhancer is selected from sorbitol or polyglycerol fatty acid ester; the stabilizer is a composite colloid composed of xanthan gum and sodium alginate at a mass ratio of (1:2)-(1:3), which forms a three-dimensional network structure in the nutrient solution to prevent the components from settling.

8. A method for preparing any of the organic nutrient solutions described in claims 1-7, characterized in that... The following steps are involved: Keratin cleavage peptides and organic acid chelating agents are mixed and stirred at 40-50℃ for 30-60 minutes to form a peptide-chelating agent complex. After cooling to 25-30℃, a solution of dissolved plant essential nutrients is added, with the addition rate controlled at ≤5L / min to prevent local supersaturation. Finally, bioactive additives and stabilizers are added, and the mixture is homogenized at 2000-5000rpm for 3-5 minutes. The pH is then adjusted to 5.5-6.5 with citric acid and stirred for 30 minutes to mature the mixture.

9. The application of any of the organic nutrient solutions described in claims 1-7 in agricultural production, characterized in that... Use in any of the following scenarios: During crop transplanting, apply a 200-300 times diluted solution as a root irrigation to promote the development of fine roots and increase root vitality by more than 10%; During flowering and fruit setting, apply a 300-500 times diluted solution as a foliar spray to increase fruit setting rate by 12%-18%; Before abiotic stress, apply a 150-250 times diluted solution as a spray to induce systemic resistance in crops and reduce malondialdehyde (MDA) content by more than 25%.

10. A plant cultivation system, characterized in that... The nutrient solution described in claims 1-7 is integrated with an intelligent application device: the nutrient solution storage tank is connected to the main irrigation pipeline via a proportional valve, and the conductivity (control range 1.2-2.8 mS / cm) and pH value (control range 5.8-6.2) of the nutrient solution are monitored in real time by an EC / pH sensor; the application program is set to drip irrigation once a week during the seedling stage (dilution ratio 300±50), and foliar spraying once every 5 days during the reproductive growth stage (dilution ratio 400±50), while the crop growth parameters are recorded and the application plan is dynamically adjusted through an Internet of Things platform.

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