Hermetia illucens compound fertilizer and preparation method thereof

Abstract

The invention discloses a hermetia illucens compound fertilizer and a preparation method thereof. The compound fertilizer for the hermetia illucens comprises 10-20 parts of amino acid liquid fertilizer for the hermetia illucens, 40-60 parts of humic acid, 80-100 parts of soybean meal and 1-10 parts of brown sugar. The invention also provides a preparation method of the composition. Compared with the prior art, the prepared hermetia illucens compound fertilizer has the characteristics of thorough hermetia illucens powder fermentation and decomposition, short fermentation period, high amino acid content, stable amino acid release and high storage stability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of organic fertilizer, in particular to a black soldier fly compound fertilizer and a preparation method thereof. BACKGROUND

[0002] Black soldier fly is a kind of water boatman family insects that can be resource production. Black soldier fly larvae can be a sustainable alternative source of protein, and is very suitable for breeding, because black soldier fly shows excellent growth rate, high density and reproduction rate, and applicability to vertical modular agriculture, and greatly reduces the land area required for production. The saprophytic ability of black soldier fly makes it able to metabolize various organic residues in nature, and promotes the conversion of food waste and residues into high-quality protein sources during breeding. Importantly, black soldier fly is rich in crude protein 45%-48% and fat 34%-35%, and its crude protein content is similar to or slightly higher than that of fresh fish, fish meal and meat and bone meal. The nutritional composition of black soldier fly is also relatively comprehensive, containing a variety of amino acids suitable for the nutrient source of essential amino acids for vegetables, fruits and other agricultural crops, and therefore is suitable for use as a fertilizer.

[0003] Amino acids can promote plant root growth, strengthen seedlings, improve plant growth, enhance the photosynthetic function of leaves and the disease resistance of crops, and have a significant yield-increasing effect on a variety of crops. However, the content of amino acids in natural soil is low, and the intake of amino acids in soil by microorganisms and soil animals makes it difficult for plants to gain an advantage in the competition for amino acids in soil. Therefore, it is necessary to artificially fertilize to supplement the amino acids required for crop growth. Artificial fertilization usually uses protease or microorganisms to degrade fish meal into amino acids as biofertilizer, and is usually a liquid fertilizer that needs to be supplemented several times. Therefore, it is necessary to provide a solid amino acid fertilizer that can be fertilized at one time.

[0004] CN118459286A discloses a compound water fertilizer and a preparation method thereof, which is composed of the following raw material components by weight percentage: biogas slurry 70%, berry solution 10%, and worm-based amino acid solution 20% to improve the nutritional quality of crops. However, the fermentation strain of the present application may be mainly derived from biogas slurry, which may have the disadvantage of low fermentation efficiency.

[0005] CN117964408A discloses a black soldier fly multifunctional amino acid liquid fertilizer and a preparation method thereof, which comprises the following steps: boiling water in boiling water to kill black soldier fly larvae, drying and grinding into powder; adding lactose and sucrose, mixing uniformly, then adding water, and then sterilizing to obtain a fermentation medium; inoculating bacillus subtilis, saccharomyces cerevisiae, lactobacillus plantarum and aspergillus niger into the respective liquid medium to obtain a bacterial suspension; mixing the bacterial suspensions of various bacteria in proportion to obtain a seed liquid; inoculating the seed liquid into the fermentation medium, mixing uniformly, then oscillating and fermenting, and then standing and fermenting to obtain a fermentation liquid; filtering to remove fermentation solid residues to obtain the black soldier fly multifunctional amino acid liquid fertilizer, which improves the decomposition efficiency of black soldier fly. However, the liquid fertilizer amino acid obtained by the invention may have the disadvantages of easy oxidation or hydrolysis, thereby reducing the content of amino acid. SUMMARY

[0006] In view of the above defects of the prior art, the black soldier fly compound fertilizer prepared by the present application has the characteristics of complete fermentation and decomposition of black soldier fly powder, short fermentation period, high amino acid content, stable amino acid release, and high storage stability.

[0007] To achieve the above-mentioned purpose, the present application provides a black soldier fly compound fertilizer, which comprises the following raw material components in parts by mass: 10-20 parts of black soldier fly amino acid liquid fertilizer, 40-60 parts of humic acid, 80-100 parts of soybean meal powder, and 1-10 parts of brown sugar. The black soldier fly amino acid liquid fertilizer is obtained by fermentation of black soldier fly worm powder and bacterial liquid; the bacterial liquid is selected from at least one of bacillus subtilis bacterial liquid, trichoderma harzianum bacterial liquid, and pseudomonas putida bacterial liquid.

[0008] Preferably, the preparation method of the black soldier fly amino acid liquid fertilizer comprises the following steps in parts by mass: Step 1, drying and crushing the dried black soldier fly bodies to obtain black soldier fly worm powder; mixing the black soldier fly worm powder, soybean meal powder, bagasse, and calcium magnesium phytate under hot air at 40-50°C to obtain pretreated composite black soldier fly powder; Step 2, uniformly mixing 65-75 parts of composite black soldier fly powder with 70-90 parts of water to obtain a fermentation medium; Step 3, inoculating the bacterial liquid into the fermentation medium at an inoculation amount of 1-3% of the total volume of the fermentation medium obtained in step 2, oscillating and fermenting at 26-30°C and 150-250 rpm, and filtering to remove fermentation solid residues to obtain the black soldier fly amino acid liquid fertilizer.

[0009] Preferably, step 2 can also be to uniformly mix 65-75 parts of composite black soldier fly powder, 0.05-0.2 parts of a fermentation promoter, and 70-90 parts of water to obtain a fermentation medium.

[0010] Further preferably, the fermentation accelerator is selected from at least one of alkaline protease, bromelain, potassium glycyrrhizinate.

[0011] As a further illustration of the present application, alkaline protease decomposes proteins by hydrolyzing peptide bonds in protein molecules, under the catalysis of the enzyme, water molecules participate in the reaction, making the peptide bond break, forming new amino and carboxyl terminals; bromelain is a natural complex protease derived from the stem of pineapple, which can recognize and cut the peptide bond in the protein molecule, and its cutting site is complementary to the protease secreted by the three-microbe system, which can expand the coverage of enzymatic reaction and significantly improve the hydrolysis efficiency of black soldier fly body protein; potassium glycyrrhizinate is a natural triterpenoid saponin surfactant, which can improve the wettability and permeability of enzyme liquid to black soldier fly powder, enhance the spatial contact frequency of protease and substrate, and enhance the permeability of microbial cell membrane, indirectly promoting the secretion and expression of extracellular protease of bacteria.

[0012] Preferably, the black soldier fly body is crushed and then dried to a water content of ≤10% after passing through a 60-100 mesh sieve; the bagasse has a water content of ≤10%.

[0013] Preferably, the fermentation time of step 3 is 70-78h.

[0014] Preferably, the bacterial liquid is selected from at least one of bacillus subtilis liquid, trichoderma harzianum liquid, and pseudomonas putida liquid.

[0015] Further preferably, the bacterial liquid is mixed by bacillus subtilis liquid, trichoderma harzianum liquid, and pseudomonas putida liquid in a mass ratio of 1-5:1-5:1-5.

[0016] As a further illustration of the present application, the black soldier fly powder is mainly composed of crude protein, fat, crude fiber, chitin, etc., bacillus subtilis can produce various enzymes such as amylase and protease, which can further decompose macromolecular substances such as starch and protein in the raw materials, provide more easily absorbed nutrients for the growth and fermentation of microorganisms, and help to improve the fermentation efficiency and raw material utilization rate; trichoderma harzianum can produce chitinase, protease, lipase, etc., which can decompose chitin, protein and fat in the black soldier fly powder in the raw materials; pseudomonas putida can secrete exopolysaccharide and surfactin, enhance the contact efficiency of insect powder and enzyme, and the addition of calcium and magnesium phytate can provide calcium, magnesium and other mineral nutrients for microorganisms, which are essential for the growth, reproduction and metabolic activity of microorganisms, and can promote enzyme synthesis and stimulate enzyme activity.

[0017] The present application also provides a preparation method of black soldier fly compound fertilizer, comprising the following preparation steps: The black soldier fly amino acid liquid fertilizer, humic acid, soybean meal powder and brown sugar are mixed uniformly according to the mass ratio, and the black soldier fly compound fertilizer is obtained.

[0018] The beneficial effects of the present application are: 1. Compared with the prior art, the black soldier fly compound fertilizer is obtained by reasonably matching the mutual action of various substances and optimizing the preparation process.

[0019] 2. Compared with the prior art, the decomposition rate of the black soldier fly powder fermentation is improved by the combination of Bacillus subtilis, Trichoderma harzianum, Pseudomonas putida, calcium magnesium phytate and bromelain, so that the fermentation is more thorough. The fermentation medium used has the characteristics of simple composition, low price and wide source of raw materials. The present application optimizes the strain ratio, combines the black soldier fly pretreatment technology and the fermentation process optimization, and can improve the rapid and sufficient decomposition of black soldier fly protein, the high conversion rate of protein to amino acid, shorten the fermentation period, and make the prepared compound fertilizer rich in types of amino acid and high in amino acid content. The raw material is rich in protein, the fermentation period is short, the types of amino acid are rich, and the decomposition rate of black soldier fly is high. DETAILED DESCRIPTION

[0020] The parameters and sources of part of the raw materials in the embodiments of the present application are as follows: The black soldier fly is from Guangzhou Wuliangsheng Technology Co., Ltd. The calcium magnesium phytate has the chemical formula C6H 14 CaMgO 24 P6, (Ca) 17-27%, (Mg) 1-6%, and the product number is S30831, which is from Shanghai Yuanye Biotechnology Co., Ltd. The alkaline protease has an enzyme activity of 400,000 U / g. The bromelain has an enzyme activity of 400,000 U / g. The Bacillus licheniformis is CICC 24534, a commercially available product, which is from China Industrial Microbial Culture Collection Center. The Trichoderma harzianum is CICC 13010, a commercially available product, which is from China Industrial Microbial Culture Collection Center. The Pseudomonas putida is CICC 20754, a commercially available product, which is from China Industrial Microbial Culture Collection Center.

[0021] The bacillus subtilis liquid, the pseudomonas putida liquid and the trichoderma harzianum liquid involved in the examples and the comparative examples of the present application are prepared by the following method: The bacillus subtilis liquid: one loop of bacillus subtilis is inoculated into a nutrient broth agar solid culture medium by using an inoculation loop, and incubated at 30 DEG C for 24 hours; a single colony with a good growth condition in the plate is picked and cultured in a bacillus subtilis liquid culture medium, and incubated at 30 DEG C and 200 rpm for 24 hours in a constant temperature incubator, and then the bacillus subtilis liquid with a concentration of 5*10 8 (CFU / mL) bacillus subtilis liquid; the bacillus subtilis liquid culture medium: peptone 5.0 g, beef extract 3.0 g, NaCl 5.0 g, distilled water 1.0 L, pH 7.0; the nutrient broth agar solid culture medium: peptone 5.0 g, beef extract 3.0 g, NaCl 5.0 g, agar 15.0 g, distilled water 1.0 L, pH 7.0.

[0022] The pseudomonas putida liquid: one loop of pseudomonas putida is inoculated into a nutrient broth agar solid culture medium by using an inoculation loop, and incubated at 30 DEG C for 24 hours; a single colony with a good growth condition in the plate is picked and cultured in a pseudomonas putida liquid culture medium, and incubated at 30 DEG C and 200 rpm for 24 hours in a constant temperature incubator, and then the pseudomonas putida liquid with a concentration of 5*10 8 (CFU / mL) pseudomonas putida liquid; the pseudomonas putida liquid culture medium: peptone 5.0 g, beef extract 3.0 g, NaCl 5.0 g, distilled water 1.0 L, pH 7.0; the nutrient broth agar solid culture medium: peptone 5.0 g, beef extract 3.0 g, NaCl 5.0 g, agar 15.0 g, distilled water 1.0 L, pH 7.0.

[0023] The trichoderma harzianum liquid: one loop of trichoderma harzianum is inoculated into a trichoderma harzianum solid culture medium for 24 hours; a single colony with a good growth condition in the plate is picked and inoculated into a trichoderma harzianum liquid culture medium for activation, and incubated at 30 DEG C and 200 rpm for 24 hours, and then the trichoderma harzianum liquid with a concentration of 5*10 8 (CFU / mL) trichoderma harzianum liquid. The trichoderma harzianum solid culture medium: 5 DEG Bé wort 1.0 L, agar 15.0 g.

[0024] Example 1 A preparation method of a black soldier fly compound fertilizer comprises the following steps: 15 kg of black soldier fly amino acid liquid fertilizer, 50 kg of humic acid, 90 kg of soybean meal powder and 5 kg of brown sugar are uniformly mixed to obtain the black soldier fly compound fertilizer.

[0025] A preparation method of the black soldier fly amino acid liquid fertilizer in the example comprises the following steps: Step 1, dry black soldier fly bodies are crushed, dried to a moisture content of 8%, and sieved through an 80-mesh screen. The sieved black soldier fly powder is mixed with sugarcane residue, soybean meal powder, and calcium-magnesium phytate, which are dried to a moisture content of 8%, at a mass ratio of 40:5:8:0.05 under hot air at 45°C to obtain pretreated composite black soldier fly powder; Step 2, 70 kg of the composite black soldier fly powder is mixed with 80 kg of water to obtain a fermentation medium; Step 3, the fermentation medium obtained in Step 2 is inoculated with Bacillus subtilis bacterial liquid at an inoculation amount of 2% of the total volume of the fermentation medium, and is subjected to 76 h of fermentation at 28°C and 200 rpm. The fermentation solid residue is removed by filtration to obtain black soldier fly amino acid liquid fertilizer.

[0026] Example 2 The difference between the preparation method of the black soldier fly compound fertilizer and Example 1 is only that the preparation method of the black soldier fly amino acid liquid fertilizer is different.

[0027] The preparation method of the black soldier fly amino acid liquid fertilizer of the present embodiment comprises the following steps: Step 1, dry black soldier fly bodies are crushed, dried to a moisture content of 8%, and sieved through an 80-mesh screen. The sieved black soldier fly powder is mixed with sugarcane residue, soybean meal powder, and calcium-magnesium phytate, which are dried to a moisture content of 8%, at a mass ratio of 40:5:8:0.05 under hot air at 45°C to obtain pretreated composite black soldier fly powder; Step 2, 70 kg of the composite black soldier fly powder is mixed with 80 kg of water to obtain a fermentation medium; Step 3, the fermentation medium obtained in Step 2 is inoculated with Pseudomonas putida bacterial liquid at an inoculation amount of 2% of the total volume of the fermentation medium, and is subjected to 76 h of fermentation at 28°C and 200 rpm. The fermentation solid residue is removed by filtration to obtain black soldier fly amino acid liquid fertilizer.

[0028] Example 3 The difference between the preparation method of the black soldier fly compound fertilizer and Example 1 is only that the preparation method of the black soldier fly amino acid liquid fertilizer is different.

[0029] The preparation method of the black soldier fly amino acid liquid fertilizer of the present embodiment comprises the following steps: Step 1, dry black soldier fly bodies are crushed, dried to a moisture content of 8%, and sieved through an 80-mesh screen. The sieved black soldier fly powder is mixed with sugarcane residue, soybean meal powder, and calcium-magnesium phytate, which are dried to a moisture content of 8%, at a mass ratio of 40:5:8:0.05 under hot air at 45°C to obtain pretreated composite black soldier fly powder; Step 2, 70 kg of the composite black soldier fly powder is mixed with 80 kg of water to obtain a fermentation medium; Step 3, inoculate the Trichoderma harzianum liquid into the fermentation medium at an inoculation amount of 2% of the total volume of the fermentation medium obtained in step 2, and ferment at 28℃ with 200 rpm oscillation for 76h, filter out the fermentation solid residues to obtain the black soldier fly amino acid liquid fertilizer.

[0030] Example 4 The difference between the preparation method of the black soldier fly compound fertilizer and example 1 is only that the preparation method of the black soldier fly amino acid liquid fertilizer is different.

[0031] The preparation method of the black soldier fly amino acid liquid fertilizer in this embodiment includes the following steps: Step 1, dry the black soldier fly bodies, crush them, and dry them to a moisture content of 8%, then pass them through an 80-mesh sieve, and mix them with sugarcane bagasse, soybean meal powder, and calcium and magnesium phytate that have been dried to a moisture content of 8% at a mass ratio of 40:5:8:0.05 under hot air at 45℃, to obtain pretreated composite black soldier fly powder; Step 2, mix 70kg of composite black soldier fly powder with 80kg of water evenly to obtain a fermentation medium; Step 3, mix Bacillus subtilis liquid and Pseudomonas putida liquid at a mass ratio of 3:2, then inoculate them into the fermentation medium obtained in step 2 at an inoculation amount of 2% of the total volume of the fermentation medium, and ferment at 28℃ with 200 rpm oscillation for 76h, filter out the fermentation solid residues to obtain the black soldier fly amino acid liquid fertilizer.

[0032] Example 5 The difference between the preparation method of the black soldier fly compound fertilizer and example 1 is only that the preparation method of the black soldier fly amino acid liquid fertilizer is different.

[0033] The preparation method of the black soldier fly amino acid liquid fertilizer in this embodiment includes the following steps: Step 1, dry the black soldier fly bodies, crush them, and dry them to a moisture content of 8%, then pass them through an 80-mesh sieve, and mix them with sugarcane bagasse, soybean meal powder, and calcium and magnesium phytate that have been dried to a moisture content of 8% at a mass ratio of 40:5:8:0.05 under hot air at 45℃, to obtain pretreated composite black soldier fly powder; Step 2, mix 70kg of composite black soldier fly powder with 80kg of water evenly to obtain a fermentation medium; Step 3, mix Bacillus subtilis liquid and Pseudomonas putida liquid at a mass ratio of 3:2, then inoculate them into the fermentation medium obtained in step 2 at an inoculation amount of 2% of the total volume of the fermentation medium, and ferment at 28℃ with 200 rpm oscillation for 76h, filter out the fermentation solid residues to obtain the black soldier fly amino acid liquid fertilizer.

[0034] Example 6 The preparation method of the black soldier fly compound fertilizer is only different from that of example 1 in that the preparation method of the black soldier fly amino acid liquid fertilizer is different.

[0035] The preparation method of the black soldier fly amino acid liquid fertilizer in the example includes the following steps: Step 1, dry the black soldier fly bodies, crush them, and dry them to a moisture content of 8%, then pass them through an 80-mesh sieve, and mix them with sugarcane residue, soybean meal powder, and calcium-magnesium phytate that have been dried to a moisture content of 8% at a mass ratio of 40:5:8:0.05 under hot air at 45°C to obtain pretreated black soldier fly compound powder; Step 2, mix 70 kg of the black soldier fly compound powder with 80 kg of water to obtain a fermentation medium; Step 3, mix the Pseudomonas putida bacterial liquid and the Trichoderma harzianum bacterial liquid at a mass ratio of 3:2, then inoculate the fermentation medium obtained in step 2 into the fermentation medium at an inoculation amount of 2% of the total volume of the fermentation medium, and perform 76 h of fermentation at 28°C and 200 rpm, then filter out the fermentation solid residues to obtain the black soldier fly amino acid liquid fertilizer.

[0036] Example 7 The preparation method of the black soldier fly compound fertilizer is only different from that of example 1 in that the preparation method of the black soldier fly amino acid liquid fertilizer is different.

[0037] The preparation method of the black soldier fly amino acid liquid fertilizer in the example includes the following steps: Step 1, dry the black soldier fly bodies, crush them, and dry them to a moisture content of 8%, then pass them through an 80-mesh sieve, and mix them with sugarcane residue, soybean meal powder, and calcium-magnesium phytate that have been dried to a moisture content of 8% at a mass ratio of 40:5:8:0.05 under hot air at 45°C to obtain pretreated black soldier fly compound powder; Step 2, mix 70 kg of the black soldier fly compound powder with 80 kg of water to obtain a fermentation medium; Step 3, mix the Pseudomonas putida bacterial liquid and the Trichoderma harzianum bacterial liquid at a mass ratio of 3:2, then inoculate the fermentation medium obtained in step 2 into the fermentation medium at an inoculation amount of 2% of the total volume of the fermentation medium, and perform 76 h of fermentation at 28°C and 200 rpm, then filter out the fermentation solid residues to obtain the black soldier fly amino acid liquid fertilizer.

[0038] Example 8 The preparation method of the black soldier fly compound fertilizer is only different from that of example 1 in that the preparation method of the black soldier fly amino acid liquid fertilizer is different.

[0039] The preparation method of the black soldier fly amino acid liquid fertilizer in the example includes the following steps: Step 1, dry black soldier fly bodies are crushed, dried to a moisture content of 8%, and sieved through an 80-mesh screen. The sieved black soldier fly powder is mixed with sugarcane residue, soybean meal powder, and calcium-magnesium phytate, which are dried to a moisture content of 8%, at a mass ratio of 40:5:8:0.05 under hot air at 45°C to obtain pretreated composite black soldier fly powder; Step 2, 70 kg of the composite black soldier fly powder and 0.1 kg of alkaline protease are uniformly mixed with 80 kg of water to obtain a fermentation medium; Step 3, Bacillus subtilis, Trichoderma harzianum, and Pseudomonas putida are mixed at a mass ratio of 3:2:2, and then inoculated into the fermentation medium obtained in Step 2 at an inoculation amount of 2% of the total volume of the fermentation medium. The mixture is subjected to 76 h of fermentation at 28°C and 200 rpm. The fermentation solid residue is removed by filtration to obtain a black soldier fly amino acid liquid fertilizer.

[0040] Example 9 The preparation method of the black soldier fly compound fertilizer differs from that of Example 1 only in the preparation method of the black soldier fly amino acid liquid fertilizer.

[0041] The preparation method of the black soldier fly amino acid liquid fertilizer comprises the following steps: Step 1, dry black soldier fly bodies are crushed, dried to a moisture content of 8%, and sieved through an 80-mesh screen. The sieved black soldier fly powder is mixed with sugarcane residue, soybean meal powder, and calcium-magnesium phytate, which are dried to a moisture content of 8%, at a mass ratio of 40:5:8:0.05 under hot air at 45°C to obtain pretreated composite black soldier fly powder; Step 2, 70 kg of the composite black soldier fly powder and 0.1 kg of alkaline protease are uniformly mixed with 80 kg of water to obtain a fermentation medium; Step 3, Bacillus subtilis, Trichoderma harzianum, and Pseudomonas putida are mixed at a mass ratio of 3:2:2, and then inoculated into the fermentation medium obtained in Step 2 at an inoculation amount of 2% of the total volume of the fermentation medium. The mixture is subjected to 76 h of fermentation at 28°C and 200 rpm. The fermentation solid residue is removed by filtration to obtain a black soldier fly amino acid liquid fertilizer.

[0042] Example 10 The preparation method of the black soldier fly compound fertilizer differs from that of Example 1 only in the preparation method of the black soldier fly amino acid liquid fertilizer.

[0043] The preparation method of the black soldier fly amino acid liquid fertilizer comprises the following steps: Step 1, dry black soldier fly bodies are crushed, dried to a moisture content of 8%, and sieved through an 80-mesh screen. The sieved black soldier fly powder is mixed with sugarcane residue, soybean meal powder, and calcium-magnesium phytate, which are dried to a moisture content of 8%, at a mass ratio of 40:5:8:0.05 under hot air at 45°C to obtain pretreated composite black soldier fly powder; Step 2, 70 kg of compound black soldier fly powder, 0.08 kg of bromelain, 0.02 kg of potassium glycyrrhizinate were mixed with 80 kg of water to obtain a fermentation medium; Step 3, the bacillus subtilis liquid, trichoderma harzianum liquid and pseudomonas putida liquid were mixed according to a mass ratio of 3:2:2, then inoculated into the fermentation medium according to a inoculation amount of 2% of the total volume of the fermentation medium obtained in step 2, and subjected to fermentation at 28℃ and 200 rpm for 76 h, and then the fermentation solid residues were removed by filtration to obtain the black soldier fly amino acid liquid fertilizer.

[0044] Comparative Example 1 The preparation method of the black soldier fly compound fertilizer of the present embodiment is different from that of Example 1 only in the preparation method of the black soldier fly amino acid liquid fertilizer.

[0045] The preparation method of the black soldier fly amino acid liquid fertilizer of the present embodiment includes the following steps: Step 1, the dried black soldier fly bodies were crushed, dried to a moisture content of 8%, and then sieved through an 80-mesh sieve, and then mixed with dried sugarcane bagasse and soybean meal powder at a mass ratio of 40:5:8 under hot air at 45℃ to obtain pretreated compound black soldier fly powder; Step 2, 70 kg of compound black soldier fly powder, 0.1 kg of alkaline protease and 80 kg of water were mixed uniformly to obtain a fermentation medium; Step 3, the bacillus subtilis liquid, trichoderma harzianum liquid and pseudomonas putida liquid were mixed according to a mass ratio of 3:2:2, then inoculated into the fermentation medium according to a inoculation amount of 2% of the total volume of the fermentation medium obtained in step 2, and subjected to fermentation at 28℃ and 200 rpm for 76 h, and then the fermentation solid residues were removed by filtration to obtain the black soldier fly amino acid liquid fertilizer.

[0046] Test Example 1 Degradation rate of black soldier fly powder.

[0047] The degradation rates of the black soldier fly powder in the black soldier fly compound fertilizers of Examples 1-10 and Comparative Example 1 were measured respectively, and the calculation formula was as follows: Degradation rate of compound black soldier fly powder (%) = (dry weight of added compound black soldier fly powder before fermentation - dry weight of filter residue after fermentation) / dry weight of added compound black soldier fly powder before fermentation x 100%.

[0048] The black soldier fly compound fertilizers obtained in Examples 1-10 and Comparative Example 1 were respectively stored in an environment with a temperature of 54℃±2℃ and a relative humidity of 20%±5% for 21 days, and then the amino acid contents before and after storage were detected by Hitachi LA8080 ultra-high-speed full-automatic amino acid analyzer, and the test results are shown in Table 1.

[0049] Table 1 Degradation rate

[0050] From the comparison of Examples 1-8 and Comparative Example 1, it can be found that the degradation rates of Examples 7 and 8 are higher. The possible reason for analysis is that the complex microbial solution of Bacillus subtilis, Pseudomonas putida and Trichoderma harzianum is added in Examples 7 and 8, Bacillus subtilis can produce amylase and protease to decompose the protein in black soldier fly; Trichoderma harzianum can produce chitinase, protease, lipase, etc., to decompose chitin, protein and fat in black soldier fly powder; Pseudomonas putida can secrete exopolysaccharide and surfactin to increase the contact efficiency of insect powder and enzyme, and the addition of calcium magnesium phytate can stimulate enzyme activity to enhance the conversion rate of amino acids.

[0051] From the comparison of Examples 8-10, it can be found that the degradation rate of Example 10 is the highest, reaching 99.42%. The possible reason for analysis is that bromelain and potassium glycyrrhizinate are added in the fermentation substrate of Example 10, bromelain is a natural complex protease derived from pineapple stems, which can complement the microbial solution to promote the degradation of black soldier fly powder in the fermentation substrate, potassium glycyrrhizinate can improve the wettability and permeability of enzyme solution to black soldier fly powder, enhance the spatial contact frequency of protease and substrate, enhance the permeability of microbial cell membrane, indirectly promote the secretion and expression of extracellular protease of microbial cells, and further promote the degradation rate.

[0052] Test Example 2 Amino acid content and amino acid conversion rate test.

[0053] The protein content of black soldier fly powder of Examples 1-10 and Comparative Example 1 was tested by Kjeldahl nitrogen determination method, and the protein content of the fermentation medium was tested. Then the amino acid content of the black soldier fly amino acid liquid fertilizer obtained from Examples 1-10 and Comparative Example 1 was detected by Hitachi LA8080 ultra-high-speed full-automatic amino acid analyzer, and then the amino acid conversion rate was calculated, the formula is as follows: Amino acid conversion rate (%) = fermented amino acid content ÷ fermentation medium protein content × 100%.

[0054] The test results are shown in Table 2.

[0055] Table 2 Amino acid content and amino acid conversion rate

[0056] From the comparison of Examples 1-3, it can be found that the amino acid conversion rate of Example 1 is high, and the possible reason for analysis is that the microbial solution used in Example 1 is Bacillus subtilis, which has higher protease production capacity than the strains in Examples 2-3.

[0057] It can be found by comparing Examples 4-6 that the amino acid conversion rate of Example 5 is high. The reason is that the bacteria liquid used in Example 5 is a composite bacteria liquid of Bacillus subtilis and Trichoderma harzianum, both of which can produce protease and have a synergistic effect when used together. The bacteria liquid used in Example 4 is a composite bacteria liquid of Bacillus subtilis and Pseudomonas putida, which also has a synergistic effect, but the effect is lower than that of Example 5. The bacteria liquid used in Example 6 is a composite bacteria liquid of Pseudomonas putida and Trichoderma harzianum, which mainly produces protease from Trichoderma harzianum and has a lower content than Bacillus subtilis, resulting in a lower effect.

[0058] It can be found by comparing Examples 4-8 and Comparative Example 1 that the amino acid conversion rate of Example 8 is high, but not much different from that of Example 7. The reason is that Example 7 adds a composite bacteria liquid of Bacillus subtilis, Pseudomonas putida and Trichoderma harzianum. Bacillus subtilis can produce amylase and protease to decompose the protein in black soldier fly. Trichoderma harzianum can produce chitinase, protease and lipase to decompose chitin, protein and fat in black soldier fly powder. Pseudomonas putida can secrete exopolysaccharide and surfactin to increase the contact efficiency of black soldier fly powder and enzymes. The three can produce synergistic effect to promote the hydrolysis of protein into amino acid. The addition of calcium and magnesium phytate can stimulate enzyme activity to enhance amino acid conversion rate. The high amino acid conversion rate of Example 8 is probably because of the addition of alkaline protease, which increases the amino acid conversion rate. However, alkaline protease has a high cost and similar effect to Example 7.

[0059] It can be found by comparing Examples 8-10 that the amino acid conversion rate of Example 10 is high. The reason is that Example 10 adds a composite bacteria liquid of Bacillus subtilis, Pseudomonas putida and Trichoderma harzianum, as well as bromelain and potassium glycyrrhizinate in the fermentation substrate. Bromelain can promote protein hydrolysis through multiple site cleavage, and potassium glycyrrhizinate can promote enzyme substrate contact and bacteria production of enzyme, achieving synergistic effect at low dosage, effectively improving protein hydrolysis efficiency and amino acid release rate, resulting in a higher conversion rate of Example 10 than Example 9.

Claims

1. A black soldier fly compound fertilizer, characterized in that: The raw material components are as follows: 10-20 parts of black soldier fly amino acid liquid fertilizer, 40-60 parts of humic acid, 80-100 parts of soybean meal powder, and 1-10 parts of brown sugar. The black soldier fly amino acid liquid fertilizer is obtained by fermenting black soldier fly powder and bacterial liquid; the bacterial liquid is selected from at least one of Bacillus subtilis bacterial liquid, Trichoderma harzianum bacterial liquid, and Pseudomonas putida bacterial liquid.

2. The black soldier fly compound fertilizer according to claim 1, wherein The preparation method of the black soldier fly amino acid liquid fertilizer comprises the following steps, calculated by parts by mass: Step 1: crushing and drying the dried black soldier fly bodies to obtain black soldier fly powder; mixing the black soldier fly powder, soybean meal powder, sugarcane bagasse, and calcium magnesium phytate to obtain composite black soldier fly powder; Step 2: Evenly mix 65-75 parts of the composite black soldier fly powder with 70-90 parts of water to obtain a fermentation medium; Step 3: inoculate the bacterial liquid into the fermentation medium at an inoculum amount of 1-3% of the total volume of the fermentation medium obtained in step 2, ferment at 26-30° C. and 150-250 rpm, and filter to remove the fermentation solid residue to obtain a black soldier fly amino acid liquid fertilizer.

3. The black soldier fly compound fertilizer according to claim 2, wherein: The step 2 may also be to uniformly mix 65-75 parts of the composite black soldier fly powder, 0.05-0.2 parts of the fermentation promoter and 70-90 parts of water to obtain a fermentation medium.

4. The black soldier fly compound fertilizer according to claim 3, wherein: The fermentation promoting agent is selected from at least one of alkaline protease, bromelain and potassium glycyrrhizate.

5. The black soldier fly compound fertilizer according to claim 2, wherein: The black soldier fly powder, soybean meal powder, sugarcane bagasse and calcium magnesium phytate are composed in a mass ratio of 30-50:5-10:3-8:0.01-0.

1.

6. The black soldier fly compound fertilizer according to claim 2, wherein: The black soldier fly bodies are crushed and passed through a 60-100 mesh sieve, and then dried to a moisture content of ≤10%; the moisture content of the sugarcane bagasse is ≤10%.

7. The black soldier fly compound fertilizer according to claim 2, wherein: The fermentation time of step 3 is 70-78 hours.

8. The method for preparing the black soldier fly compound fertilizer according to any one of claims 1 to 7, characterized in that: The method comprises the following preparation steps: The black soldier fly amino acid liquid fertilizer, humic acid, soybean meal powder and brown sugar are evenly mixed according to a mass ratio to obtain a black soldier fly compound fertilizer.

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