Application of a bacillus amyloliquefaciens in soybean processing wastewater

Abstract

The application provides application of a bacillus amyloliquefaciens in soy product processing wastewater, and belongs to the technical field of biotechnology. The bacillus amyloliquefaciens with a strain preservation number of CCTCC NO: M2021847 is used as a fermentation strain, and soy product processing wastewater is used as a main component of a culture medium for fermentation to prepare bacillus amyloliquefaciens fertilizer. The fertilizer can be used in agricultural production to obviously improve crop yield, especially the base stem diameter of crops, thereby playing a role in anti-lodging and anti-natural disasters, reducing the use amount of traditional fertilizers, reducing costs, realizing resource utilization of soy product wastewater, and reducing wastewater discharge.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of biotechnology, in particular, the application of a bacillus amyloliquefaciens in soy product processing wastewater. BACKGROUND

[0002] Bacillus amyloliquefaciens is a gram-positive bacterium belonging to the genus Bacillus, which can secrete various important enzymes, including polysaccharide-degrading enzymes such as alpha-amylase, cellulase, chitosanase, etc.; protein-degrading enzymes such as protease, rennet, etc.; and other important enzymes such as laccase, phytase, etc.; In addition, Bacillus amyloliquefaciens can also produce various protein antagonists, such as cell wall-degrading enzymes, antibacterial peptides and other antibacterial proteins. Therefore, Bacillus amyloliquefaciens has important applications in the fields of plant and animal disease control, growth promotion and colonization, as well as food industry, environmental protection, medicine and cosmetics industry, etc.

[0003] In recent years, the market size of soy products has increased year by year, and new types of soy products have also emerged. According to statistics, as of 2020, there were about 300,000 soy product enterprises in China; During the production of soy products, a large amount of wastewater is discharged. According to statistics, for every ton of soybeans processed, about 30-50 tons of wastewater are generated, including 10 tons of cleaning wastewater, 1 ton of soybean soaking wastewater, and 4-5 tons of yellow slurry water. Soy product wastewater is high-concentration COD organic wastewater, containing a large amount of active substances such as protein, soy isoflavone, soy saponin and oligosaccharide, as well as rich nutrients such as phosphorus, calcium, potassium, iron, B vitamins, monosaccharides, organic acids and amino acids, which are prone to acidification and deterioration. How to realize the comprehensive utilization of soy product wastewater has become a hot and difficult research topic.

[0004] The invention patent with publication number "CN114410517B" discloses a bacillus amyloliquefaciens that can be used to produce 2,5 furandicarboxylic acid, with preservation number CCTCC NO: M2021847. The bacillus amyloliquefaciens is screened from papermaking wastewater and has strong 5-hydroxymethylfurfural tolerance. When cultured in the medium, the tolerance concentration range of 5-hydroxymethylfurfural is 0-20 mM. The present application aims to study the application of the bacillus amyloliquefaciens in more fields. SUMMARY

[0005] In view of the shortcomings of the prior art, the present application provides the application of a bacillus amyloliquefaciens in soy product processing wastewater, which not only realizes the resource utilization of soy product processing wastewater, but also realizes the low-cost production of bacillus amyloliquefaciens fertilizer. The produced fertilizer can significantly improve crop yield and increase crop base stem diameter, reducing the use of traditional fertilizers.

[0006] The technical scheme of the present application is as follows:

[0007] Application of a strain of Bacillus amyloliquefaciens in wastewater from soybean product processing, wherein the strain preservation number of Bacillus amyloliquefaciens is CCTCC NO: M2021847.

[0008] Preferably, the application of a strain of Bacillus amyloliquefaciens in soybean product processing wastewater involves using soybean product processing wastewater as the main component of the culture medium to ferment Bacillus amyloliquefaciens and prepare Bacillus amyloliquefaciens fertilizer.

[0009] Preferably, the wastewater from soybean product processing is yellow slurry and soybean soaking wastewater, and the volume ratio of the yellow slurry to the soybean soaking wastewater is 1-4:1-6.

[0010] Preferably, the application method specifically includes the following steps:

[0011] (1) Activation of strains: Bacillus amyloliquefaciens was streaked on LB solid medium and incubated in an incubator at 30-37℃ for 18-36 hours to obtain activated Bacillus amyloliquefaciens cells;

[0012] (2) Preparation of shake flask seed culture: Pick the activated Bacillus amyloliquefaciens cells from step (1) and inoculate them into shake flask seed culture medium containing soybean processing wastewater. Place the medium in a shaker at 30-37℃ and incubate at 210-230 rpm for 24-36 hours to obtain shake flask seed culture.

[0013] (3) Preparation of fermentation tank seed liquid: The shake flask seed liquid from step (2) is inoculated into the fermentation tank seed liquid culture medium containing soybean product processing wastewater at an inoculation rate of 2-5% (V / V). The culture is carried out at 30-37℃, 100-300rpm, aeration rate of 0.5-1.0V / Vm, pH 6.8-7.5, and cultured for 16-24h to obtain fermentation tank seed liquid;

[0014] (4) Fermentation: Inoculate the seed culture from step (3) into a fermenter containing soybean processing wastewater at an inoculation rate of 30-50% (V / V). Maintain the culture temperature at 30-37℃, 100-200 rpm, aeration rate of 0.3-1.0V / Vm, and pH 7.0-7.5 for 20-36 hours. Fermentation continues until the bacterial cell concentration reaches 2.0-5.0 × 10⁻⁶ cells / mL. 9 When the concentration of CFU / mL is reached, fermentation is stopped, and the fermentation broth of Bacillus amyloliquefaciens is obtained.

[0015] (5) Filling: The Bacillus amyloliquefaciens fermentation broth from step (4) is aseptically dispensed to obtain Bacillus amyloliquefaciens fertilizer.

[0016] Preferably, the components of the LB solid culture medium in step (1) are: 10 g / L peptone, 5 g / L yeast extract, 10 g / L sodium chloride, and 20 g / L agar powder.

[0017] Preferably, the components of the shake flask seed culture medium in step (2) are: glucose 5-15 g / L, yeast extract 1-5 g / L, MgSO4 0.1-0.5 g / L, soybean product processing wastewater 10-20% (V / V), with the remainder being water, and the pH adjusted to 6.5-7.5.

[0018] Preferably, the components of the seed culture medium in the fermenter in step (3) are: glucose 8-20 g / L, MgSO4 0.2-0.8 g / L, soybean processing wastewater 40-60% (V / V), with the remainder being water, and the pH is adjusted to 6.5-7.5.

[0019] Preferably, the components of the fermentation tank in step (4) are: molasses 2-10 g / L, MgSO4 0.1-0.5 g / L, FeSO4 0.1-0.3 g / L, soybean product processing wastewater 80-100% (V / V), with the remainder being water, and the pH is adjusted to 6.5-8.5.

[0020] The beneficial effects of this invention are:

[0021] The microbial fertilizer prepared using Bacillus amyloliquefaciens with accession number CCTCC NO: M2021847 can effectively increase crop yield, especially the basal stem diameter of crops, thereby playing a role in resisting lodging and natural disasters, reducing the amount of traditional fertilizer used, and realizing the resource utilization of soybean product wastewater, which is economical and environmentally friendly. Detailed Implementation

[0022] The following description is based on specific embodiments:

[0023] Example 1:

[0024] The preparation of Bacillus amyloliquefaciens fertilizer was carried out using wastewater from mung bean starch processing (yellow pulp water and bean soaking wastewater, with a volume ratio of 3:2) as the main culture medium. The specific steps are as follows:

[0025] (1) Activation of bacterial strain: Bacillus amyloliquefaciens (CCTCC NO: M2021847) preserved in glycerol tubes was streaked on LB solid medium and incubated in a 37℃ incubator for 20h to obtain activated Bacillus amyloliquefaciens cells;

[0026] The LB solid culture medium consists of: 10 g / L peptone, 5 g / L yeast extract, 10 g / L sodium chloride, and 20 g / L agar powder.

[0027] (2) Preparation of seed culture in shake flask: Pick the activated Bacillus amyloliquefaciens cells from step (1) and inoculate them into the seed culture medium in shake flask. Place the culture in a shaker at 37°C and incubate at 220 rpm for 24 h to obtain the seed culture in shake flask.

[0028] The shake flask seed culture medium consists of: 8 g / L glucose, 2 g / L yeast extract, 0.5 g / L MgSO4, 10% (V / V) mung bean starch processing wastewater, with the remainder being water, and the pH is adjusted to 7.2.

[0029] (3) Preparation of fermenter seed liquid: The shake flask seed liquid in step (2) was inoculated into the fermenter seed liquid culture medium at an inoculation amount of 5% (V / V), and cultured at 37℃, 200rpm, aeration rate of 0.5VVm, pH 7.0 for 18h to obtain fermenter seed liquid;

[0030] The components of the seed culture medium in the fermenter are: 15 g / L glucose, 0.6 g / L MgSO4, 50% (V / V) mung bean starch processing wastewater, with the remainder being water, and the pH is adjusted to 7.0.

[0031] (4) Fermentation: The seed culture from step (3) was inoculated into a fermenter containing mung bean starch processing wastewater at an inoculation rate of 30% (V / V). The fermentation was carried out at 37°C, 150 rpm, and an aeration rate of 1.0V / Vm, maintaining a pH of 7.0, for 36 hours until the cell concentration reached 3.3 × 10⁻⁶. 9 CFU / mL, stop fermentation, and obtain Bacillus amyloliquefaciens fermentation broth;

[0032] The fermentation tank consists of: mung bean starch processing wastewater, molasses 6 g / L, MgSO4 0.3 g / L, FeSO4 0.2 g / L, and pH adjusted to 7.4.

[0033] (5) Filling: The Bacillus amyloliquefaciens fermentation broth obtained in step (4) is aseptically dispensed into Bacillus amyloliquefaciens liquid fertilizer.

[0034] The nutrient composition of the microbial fertilizer prepared above was tested, and the results are as follows: total nutrients (N+P2O5+K2O) 14.62%, miscellaneous bacteria rate 3.7%, protein content 0.98%, reducing sugar 0.82%, fecal coliform count 43 CFU / mL, cadmium 1.6 mg / kg, arsenic 8.1 mg / kg, lead 24 mg / kg, chromium 85 mg / kg, mercury 0.8 mg / kg, meeting the industry standard NY / T798-2015 "Compound Microbial Fertilizer".

[0035] Example 2:

[0036] The preparation of Bacillus amyloliquefaciens fertilizer was carried out using wastewater from mung bean starch processing (yellow whey and bean soaking wastewater, volume ratio 4:5) as the main culture medium. The specific steps are as follows:

[0037] (1) Activation of bacterial strain: Bacillus amyloliquefaciens (CCTCC NO: M2021847) preserved in glycerol tubes was streaked on LB solid medium and incubated in a 32℃ incubator for 30h to obtain activated Bacillus amyloliquefaciens cells;

[0038] The LB solid culture medium consists of: 10 g / L peptone, 5 g / L yeast extract, 10 g / L sodium chloride, and 20 g / L agar powder.

[0039] (2) Preparation of seed culture in shake flask: Pick the activated Bacillus amyloliquefaciens cells from step (1) and inoculate them into the seed culture medium in shake flask. Place the culture in a shaker at 32℃ and incubate at 210 rpm for 28 h to obtain the seed culture in shake flask.

[0040] The shake flask seed culture medium consists of: 8 g / L glucose, 2 g / L yeast extract, 0.5 g / L MgSO4, 10% (V / V) mung bean starch processing wastewater, with the remainder being water, and the pH is adjusted to 7.5.

[0041] (3) Preparation of fermenter seed liquid: The shake flask seed liquid in step (2) was inoculated into the fermenter seed liquid culture medium at an inoculation amount of 3% (V / V), and cultured at 32℃, 150rpm, aeration rate of 0.8VVm, pH 7.2 for 22h to obtain fermenter seed liquid;

[0042] The components of the seed culture medium in the fermenter are: 15 g / L glucose, 0.6 g / L MgSO4, 55% (V / V) mung bean starch processing wastewater, with the remainder being water, and the pH is adjusted to 7.2.

[0043] (4) Fermentation: The seed culture from step (3) was inoculated into a fermenter containing mung bean starch processing wastewater at an inoculation rate of 35% (V / V). The fermentation was carried out at 32℃, 180 rpm, and an aeration rate of 0.8V / Vm, maintaining a pH of 7.2, for 30 hours until the cell concentration reached 2.8 × 10⁻⁶. 9 CFU / mL, stop fermentation, and obtain Bacillus amyloliquefaciens fermentation broth;

[0044] The fermentation tank consists of: wastewater from soybean product processing, molasses 5 g / L, MgSO4 0.35 g / L, FeSO4 0.25 g / L, and pH adjusted to 7.2.

[0045] (5) Filling: The Bacillus amyloliquefaciens fermentation broth obtained in step (4) is aseptically dispensed into Bacillus amyloliquefaciens liquid fertilizer.

[0046] The nutrient composition of the microbial fertilizer prepared above was tested, and the results are as follows: total nutrients (N+P2O5+K2O) 11.32%, miscellaneous bacteria rate 3.1%, protein content 0.82%, reducing sugar 0.76%, fecal coliform count 40 CFU / mL, cadmium 1.5 mg / kg, arsenic 8.3 mg / kg, lead 20 mg / kg, chromium 86 mg / kg, mercury 0.7 mg / kg, meeting the industry standard NY / T798-2015 "Compound Microbial Fertilizer".

[0047] Experimental Example 1:

[0048] The effect of Bacillus amyloliquefaciens fertilizer prepared in Example 1 on enhancing the efficacy of cucumber.

[0049] The cucumber variety tested was Zhongnong 116. The experimental site was located in Zhanglou Town, Chengwu County, Heze City, Shandong Province. The cucumbers were grown in open field on April 20, 2022. The soil in the experimental site was yellow loess soil, with flat terrain and uniform fertility.

[0050] Experimental Methods: During cucumber cultivation, five different treatments were set up: Group CK received no fertilizer; Group A received all conventional fertilizers; Group B received a mixture of 80% conventional fertilizer and 20% Bacillus amyloliquefaciens fertilizer; Group C received a mixture of 60% conventional fertilizer and 40% Bacillus amyloliquefaciens fertilizer; and Group D received a mixture of 40% conventional fertilizer and 60% Bacillus amyloliquefaciens fertilizer. All percentages mentioned above are by weight. Both conventional fertilizer and Bacillus amyloliquefaciens fertilizer were added twice, once during the seedling stage and once during the peak fruiting stage. Other management practices were the same as conventional cultivation management.

[0051] The mixing ratios of nitrogen, phosphorus, and potassium fertilizers in conventional fertilizers and the specific fertilization plans are shown in Table 1 below:

[0052] Table 1. Different processing methods

[0053]

[0054] After the cucumbers matured, they were harvested. The differences in basal stem diameter, cucumber length, number of fruits per plant, and weight per cucumber under different treatments were measured. The results are shown in Table 2.

[0055] Table 2. Cucumber characteristics under different treatments

[0056] Treatment group Base stem diameter (cm) Melon length (cm) Single melon weight (g) Number of results per plant (piece) CK 0.52±0.04 32.4±0.6 215.2±3.2 6.2±0.2 A 0.56±0.05 33.5±0.3 226.4±2.6 6.5±0.4 B 0.58±0.02 33.8±0.5 233.5±4.2 6.4±0.3 C 0.68±0.04 34.2±0.7 241.3±2.7 7.0±0.2 D 0.65±0.03 34.0±0.2 237.5±2.1 6.9±0.1

[0057] From Table 2, we can obtain:

[0058] Compared with the control group CK, the cucumber phenotypic indicators of other treatment groups with the addition of conventional fertilizer and microbial fertilizer were improved to varying degrees.

[0059] Compared with treatment group A, the weight of cucumbers in treatment groups B, C, and D increased by 3.1%, 6.6%, and 4.9%, respectively; this indicates that the Bacillus amyloliquefaciens fertilizer prepared in Example 1 has a significant promoting effect on cucumber growth, with treatment group C showing the best effect.

[0060] Compared with treatment group A, the cucumber length and number of fruits per plant in treatment groups B, C, and D did not differ significantly, but the basal stem diameter increased significantly, by 3.6%, 21.4%, and 16.1%, respectively. This indicates that applying Bacillus amyloliquefaciens fertilizer can effectively increase the basal stem diameter and yield of cucumbers, with treatment group C showing the best effect. It can be seen that when the weight ratio of conventional fertilizer to Bacillus amyloliquefaciens fertilizer is 6:4, the fertilization effect is relatively good.

[0061] The thickness of the cucumber basal stem is an important indicator for evaluating the vigor and yield of the plant. In treatment group C, the thickness of the cucumber basal stem was significantly increased compared with other treatment groups. As a result, the cucumber length, weight of a single cucumber, and number of fruits per plant were all higher than those in other treatment groups. In addition, the increased thickness of the crop basal stem can effectively play a role in preventing lodging, thereby improving the crop's ability to resist natural disasters such as strong winds and rainstorms.

[0062] Experimental Example 2:

[0063] Unlike Experiment 1, this experiment used the Bacillus amyloliquefaciens fertilizer prepared in Example 2. The effect of the fertilizer on enhancing the efficiency of cucumber was measured in the same manner as in Experiment 1. The results are shown in Table 3.

[0064] Table 3. Cucumber characteristics under different treatments

[0065] Treatment group Base stem diameter (cm) Melon length (cm) Single melon weight (g) Number of results per plant (piece) CK 0.51±0.06 32.3±0.4 215.5±2.6 6.1±0.3 A 0.55±0.04 33.4±0.4 225.8±1.9 6.5±0.5 B 0.58±0.05 33.7±0.3 233.7±3.4 6.5±0.4 C 0.67±0.03 34.3±0.4 240.2±2.5 6.9±0.2 D 0.64±0.05 34.1±0.3 236.6±1.8 6.8±0.1

[0066] As shown in Table 3, compared with treatment group A, the single cucumber weight of treatment groups B, C, and D increased by 3.5%, 6.4%, and 4.8%, respectively, and the basal stem diameter increased by 5.5%, 21.8%, and 16.4%, respectively, with treatment group C showing the best effect. This indicates that applying Bacillus amyloliquefaciens fertilizer can effectively increase the basal stem diameter and yield of cucumbers, and the effect is best when 60% conventional fertilizer is mixed with 40% Bacillus amyloliquefaciens fertilizer.

[0067] Comparative Example 1:

[0068] Unlike Example 1, this comparative example used *Bacillus amyloliquefaciens* (CGMCC 1.8719, purchased from the China General Microbiological Culture Collection Center) as the fermentation strain. Following the same fermentation steps as in Example 1, wastewater from mung bean starch processing was used as the main culture medium to prepare *Bacillus amyloliquefaciens* fertilizer. The effect of the fertilizer on enhancing cucumber efficacy was measured in the same manner as in Experimental Example 1. The results are shown in Table 4.

[0069] Table 4. Cucumber traits under different treatments

[0070] Treatment group Base stem diameter (cm) Melon length (cm) Single melon weight (g) Number of results per plant (piece) CK 0.51±0.03 32.2±0.5 215.1±2.9 6.2±0.3 A 0.56±0.04 33.3±0.4 226.2±2.3 6.4±0.3 B 0.57±0.03 33.5±0.3 230.4±2.8 6.4±0.2 C 0.60±0.03 34.0±0.4 237.2±2.7 6.7±0.4 D 0.59±0.02 33.8±0.4 234.6±1.9 6.5±0.1

[0071] As shown in Table 4, compared with treatment group A, the single cucumber weight of treatment groups B, C, and D increased by 1.9%, 4.9%, and 3.7%, respectively, and the basal stem diameter increased by 1.8%, 7.1%, and 5.3%, respectively, with treatment group C showing the best effect. This indicates that the microbial fertilizer prepared using common Bacillus amyloliquefaciens as the fermentation strain has a certain promoting effect on various traits of cucumber, but the promoting effect is not as good as that of Bacillus amyloliquefaciens used in this invention.

[0072] It is evident that applying Bacillus amyloliquefaciens (CCTCC NO: M2021847) microbial fertilizer can effectively improve the rhizosphere microecological balance of crops, enhance soil fertility, promote cucumber plant growth, and thus significantly improve cucumber traits.

[0073] Comparative Example 2:

[0074] Unlike Example 1, this comparative example used *Bacillus licheniformis* (CGMCC 1.7461, purchased from the China General Microbiological Culture Collection Center) as the fermentation strain. Following the same fermentation steps as in Example 1, wastewater from mung bean starch processing was used as the main culture medium to prepare *Bacillus licheniformis* inoculant fertilizer. The effect of the inoculant fertilizer on enhancing cucumber efficacy was measured in the same manner as in Experimental Example 1. The results are shown in Table 5.

[0075] Table 5. Cucumber characteristics under different treatments

[0076] Treatment group Base stem diameter (cm) Melon length (cm) Single melon weight (g) Number of results per plant (piece) CK 0.51±0.02 32.3±0.3 215.2±2.4 6.2±0.4 A 0.56±0.03 33.2±0.5 226.3±2.5 6.4±0.2 B 0.58±0.02 33.5±0.4 230.2±2.6 6.4±0.2 C 0.61±0.04 34.1±0.3 236.9±1.8 6.6±0.3 D 0.60±0.02 33.9±0.3 234.3±1.2 6.5±0.2

[0077] As shown in Table 5, compared with treatment group A, the weight of cucumbers in treatment groups B, C, and D increased by 1.7%, 4.7%, and 3.5%, respectively, and the stem diameter at the base increased by 3.6%, 8.9%, and 7.1%, respectively, with treatment group C showing the best effect. This indicates that the microbial fertilizer prepared using Bacillus licheniformis as the fermentation strain has a certain promoting effect on various traits of cucumbers, but the promoting effect is not as good as that of Bacillus amyloliquefaciens used in this invention.

[0078] Comparative Example 3:

[0079] Unlike Example 1, this comparative example only used the yellow slurry from mung bean starch processing wastewater as the main culture medium for fermentation to prepare Bacillus amyloliquefaciens fertilizer. Other fermentation steps were the same as in Example 1. The application effect of the fertilizer on cucumber enhancement was measured using the same addition method as in Experiment 1. The results are shown in Table 6.

[0080] Table 6. Cucumber traits under different treatments

[0081] Treatment group Base stem diameter (cm) Melon length (cm) Single melon weight (g) Number of results per plant (piece) CK 0.51±0.05 32.3±0.4 215.3±2.5 6.1±0.4 A 0.55±0.03 33.2±0.5 223.2±3.1 6.4±0.2 B 0.59±0.02 33.4±0.2 228.4±2.8 6.5±0.3 C 0.62±0.04 34.0±0.5 236.5±1.9 6.8±0.1 D 0.60±0.02 33.7±0.3 232.8±2.3 6.6±0.2

[0082] Table 6 shows that the treatment groups with added microbial fertilizer (B, C, and D) were more effective than the conventional fertilization treatment group (A), indicating that the Bacillus amyloliquefaciens fertilizer prepared using only yellow slurry as the main component of the culture medium also has an improving effect on cucumber traits. Among them, compared with treatment group A, the single cucumber weight of treatment groups B, C, and D increased by 2.3%, 6.0%, and 4.3%, respectively, and the basal stem diameter increased by 7.3%, 12.7%, and 9.0%, respectively, with treatment group C showing the best effect. It is worth noting that the improvement of Comparative Example 3 was smaller than that of Experimental Example 1 (using yellow slurry and soybean soaking wastewater as the main components of the culture medium). The main reason may be that soybean soaking wastewater contains a variety of substances such as protein, polysaccharide, organic acid, mineral, and vitamin. These substances are decomposed and metabolized by the strain during the preparation of Bacillus amyloliquefaciens fertilizer, which can produce a variety of beneficial substances that promote the growth of cucumber plants, thereby improving cucumber traits.

[0083] In summary, the microbial fertilizer prepared by Bacillus amyloliquefaciens with accession number CCTCC NO: M2021847 can effectively increase crop yield, especially the basal stem diameter of crops, thereby playing a role in lodging resistance and resistance to natural disasters, reducing the amount of traditional fertilizer used, and realizing the resource utilization of soybean product wastewater, which is economical and environmentally friendly.

Claims

1. Application of a strain of *Bacillus amyloliquefaciens* in soybean product processing wastewater, wherein the strain preservation number of *Bacillus amyloliquefaciens* is CCTCC NO: M2021847, and the application method is to use soybean product processing wastewater as one of the components of the culture medium to ferment *Bacillus amyloliquefaciens* and prepare *Bacillus amyloliquefaciens* inoculum fertilizer; wherein, The wastewater from the soybean product processing consists of yellow slurry and soybean soaking wastewater.

2. The application as described in claim 1, characterized in that, The volume ratio of the yellow slurry water to the soybean soaking wastewater is 1~4:1~6.

3. The application as described in claim 1, characterized in that, The application method specifically includes the following steps: (1) Activation of bacterial strain: Bacillus amyloliquefaciens was streaked on LB solid medium and incubated in an incubator at 30-37℃ for 18-36h to obtain activated Bacillus amyloliquefaciens cells; (2) Preparation of shake flask seed culture: Take the activated Bacillus amyloliquefaciens cells from step (1) and inoculate them into the shake flask seed culture medium containing soybean processing wastewater. Place it in a shaker at 30~37℃ and incubate at 210~230rpm for 24~36h to obtain shake flask seed culture. (3) Preparation of fermentation tank seed liquid: The shake flask seed liquid in step (2) is inoculated into the fermentation tank seed liquid culture medium containing soybean product processing wastewater at an inoculation amount of 2-5% by volume. The culture is carried out at 30-37℃, 100-300rpm, aeration rate of 0.5-1.0VVm, pH 6.8-7.5 for 16-24h to obtain fermentation tank seed liquid; (4) Fermentation: Inoculate the seed culture from step (3) into a fermenter containing soybean processing wastewater at an inoculation rate of 30-50% by volume. Incubate at 30-37℃, 100-200 rpm, aeration rate of 0.3-1.0 VVm, pH 7.0-7.5 for 20-36 hours. When the cell concentration reaches 2.0-5.0 × 10⁻⁶ cells / mL... 9 When the concentration of CFU / mL is reached, fermentation is stopped, and the fermentation broth of Bacillus amyloliquefaciens is obtained. (5) Filling: The Bacillus amyloliquefaciens fermentation broth from step (4) is aseptically dispensed to obtain Bacillus amyloliquefaciens fertilizer.

4. The application as described in claim 3, characterized in that, The components of the LB solid culture medium in step (1) are: 10 g / L peptone, 5 g / L yeast extract, 10 g / L sodium chloride, and 20 g / L agar powder.

5. The application as described in claim 3, characterized in that, The components of the shake flask seed culture medium in step (2) are: glucose 5~15g / L, yeast extract 1~5g / L, MgSO4 0.1~0.5g / L, soybean processing wastewater 10~20% by volume, with the remainder being water, and the pH adjusted to 6.5~7.

5.

6. The application as described in claim 3, characterized in that, The components of the seed culture medium in the fermenter in step (3) are: glucose 8~20g / L, MgSO4 0.2~0.8g / L, soybean product processing wastewater 40~60% by volume, and the remainder is water, with the pH adjusted to 6.5~7.

5.

7. The application as described in claim 3, characterized in that, The components of the fermentation tank in step (4) are: molasses 2~10g / L, MgSO4 0.1~0.5g / L, FeSO4 0.1~0.3g / L, soybean product processing wastewater 80~100% by volume, with the remainder being water, and the pH is adjusted to 6.5~8.5.

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