Bacillus licheniformis BL-C15 and application thereof

Abstract

The present application belongs to the technical field of microorganisms, and particularly relates to a bacillus licheniformis BL-C15 and application thereof. The present application provides a bacillus licheniformis BL-C15, which is characterized in that the bacillus licheniformis BL-C15 is preserved in the China General Microbiological Culture Collection Center on November 25, 2024, has a preservation number of CGMCC No. 32787, and has a preservation address of No. 3, Xili, Beichen, Beijing, China. The strain has the characteristics of high-alkali tolerance, salt tolerance and acid production, can effectively repair saline-alkali degraded soil, has a significant plant growth-promoting effect, and has important application value in the field of saline-alkali soil repair. The strain can also be used for preparing a microbial product for repairing saline-alkali soil.

Description

Technical Field

[0001] This invention belongs to the field of microbial technology, specifically relating to a strain of Bacillus licheniformis BL-C15 and its applications. Background Technology

[0002] Soil salinization is a global problem threatening land use and the ecological environment. Currently, approximately 954 million hectares of land worldwide are salinized to varying degrees, accounting for about 7% of the total land area. As the country with the third largest distribution of saline-alkali land globally, China has approximately 1.5 billion mu (100 million hectares) of saline-alkali land, equivalent to the area of ​​my country's existing arable land. Saline-alkali land is currently an important reserve resource for my country, and its rational development and utilization are crucial for ensuring my country's food security. Therefore, it is urgent to find a method for improving and restoring saline-alkali soil.

[0003] After years of research and practical application, traditional saline-alkali soil improvement measures mainly include water drainage, soil replacement, and chemical neutralization. However, these measures often suffer from problems such as being labor-intensive and time-consuming, causing secondary pollution, or having short-lasting effects, making it difficult to sustainably improve the soil. Microbial soil remediation measures have better long-lasting effects and are time-saving and labor-saving, making them a promising approach to saline-alkali soil improvement. However, currently used microbial strains are mostly screened based on salt tolerance, often neglecting the alkali tolerance of the strains. In addition to high salt content, saline-alkali soils often have an alkaline pH, especially severely saline-alkali soils where the pH can reach above 9.5. Therefore, finding a microbial strain that is both salt-tolerant and alkali-tolerant, and also promotes soil growth, has become extremely urgent. Summary of the Invention

[0004] In view of this, the present invention provides a strain of Bacillus licheniformis BL-C15 and its application. This strain of Bacillus licheniformis BL-C15 has good salt and alkali tolerance characteristics, can reproduce normally in saline-alkali soil with high alkali and salt content, and can effectively improve saline-alkali soil. At the same time, this strain also has a significant growth-promoting effect on plants, which can ensure the normal growth of plants in saline-alkali soil.

[0005] To solve the above technical problems, the first aspect of the present invention provides a strain of Bacillus licheniformis BL-C15, which was deposited on November 25, 2024, at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC No. 32787 and address at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing.

[0006] Compared with existing technologies, the Bacillus licheniformis BL-C15 provided by this invention not only possesses high alkali and salt tolerance, but can also grow and reproduce normally in culture media with a pH of 12 and / or a salt content of 10 wt%, playing an important role in the remediation of saline-alkali soils. Simultaneously, the Bacillus licheniformis BL-C15 can effectively degrade inorganic phosphorus in the soil and also has potassium-solubilizing effects. The large amount of indole-3-acetic acid (IAA) it produces can also promote plant growth, and the extracellular polymeric substance (EPS) it generates enhances the salt tolerance of plants, thus ensuring that plants can grow rapidly in saline-alkali or compacted degraded soils. This Bacillus licheniformis BL-C15 can not only effectively improve saline-alkali soils in coastal areas, but also has significant plant growth-promoting effects, making it of significant application value in the remediation of saline-alkali soils, especially in coastal areas.

[0007] A second aspect of the present invention provides the use of the above-mentioned Bacillus licheniformis BL-C15 as a plant growth promoter.

[0008] A third aspect of the present invention provides the application of the above-mentioned Bacillus licheniformis BL-C15 as a product for degrading inorganic phosphorus.

[0009] A fourth aspect of the present invention provides the use of the above-mentioned Bacillus licheniformis BL-C15 as a potassium-solubilizing product.

[0010] A fifth aspect of the present invention provides the use of the above-mentioned Bacillus licheniformis BL-C15 in the production of indole-3-acetic acid (IAA).

[0011] A sixth aspect of the present invention provides the use of the above-mentioned Bacillus licheniformis BL-C15 in the production of extracellular polymeric EPS.

[0012] A seventh aspect of the present invention provides the use of the above-mentioned Bacillus licheniformis BL-C15 as a product for improving saline-alkali soil.

[0013] Saline-alkali soils have high salt content and strong alkalinity, and are prone to compaction or infertility after degradation.

[0014] In conjunction with the seventh aspect, the salt content of the saline-alkali soil is not less than 0.1 wt%.

[0015] Preferably, the salt content of the saline-alkali soil is 0.1 wt% to 10 wt%.

[0016] More preferably, the saline-alkali soil has a salt content of 3wt% to 5wt%.

[0017] In conjunction with the seventh aspect, the pH of the saline-alkali soil is 8–12.

[0018] Preferably, the pH of the saline-alkali soil is 9 to 12, and can be any value between 9, 10, 11, 12 or any two of them.

[0019] The eighth aspect of the present invention provides a microbial inoculant comprising the above-mentioned Bacillus licheniformis BL-C15.

[0020] Preferably, the microbial agent further includes a microbial carrier, which may be at least one of biochar, diatomaceous earth, or attapulgite.

[0021] Preferably, the microbial agent can be prepared by the following method: BL-C15 strain is activated by streaking on LB solid medium and cultured for 46-50 h. The bacterial growth is picked and inoculated into 100 mL of sterilized LB liquid medium and cultured for 24 h at 27-29 °C and 200 rpm / min in a shaker. This seed culture is then expanded until more than 80% of the culture produces spores to obtain BL-C15 bacterial solution. The obtained bacterial solution is adsorbed onto a microbial carrier and dried to obtain the microbial agent. Attached Figure Description

[0022] Figure 1 This is a plate-shaped image showing the growth-promoting effect of Bacillus licheniformis BL-C15 on wheat.

[0023] Figure 2 The images show the growth of Bacillus licheniformis BL-C15 in saline-alkali medium, where (a) is a growth image of Bacillus licheniformis BL-C15 in medium with a salt concentration of 10 wt%, and (b) is a growth image of Bacillus licheniformis BL-C15 in medium with a pH of 12.

[0024] Figure 3 Morphological characteristics of Bacillus licheniformis BL-C15;

[0025] Figure 4 Phylogenetic tree of Bacillus licheniformis BL-C15 based on the gyrb gene;

[0026] Figure 5 The graph shows the results of the inorganic phosphorus solubility test for Bacillus licheniformis BL-C15.

[0027] Figure 6 The image shows the test results for 3-indoleacetic acid (IAA) production by Bacillus licheniformis BL-C15.

[0028] Figure 7 Photographs showing the growth-promoting effect of Bacillus licheniformis BL-C15 on wheat. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0030] Unless otherwise specified, the experimental methods used in the following examples and comparative examples are conventional methods in the art.

[0031] Unless otherwise specified, all raw materials and reagents used in the following examples and comparative examples were obtained commercially.

[0032] The LB solid medium formulation in the following examples is as follows: 10g tryptone, 5g yeast extract, 10g NaCl, 15-20g agar, and distilled water to make up to 1L, with the pH adjusted to 7.0-7.2.

[0033] The formula for LB solid medium containing 3% salt and pH 9 is as follows: 10g tryptone, 5g yeast extract, 30g NaCl, 15-20g agar, and distilled water to make up to 1L. Adjust the pH to 9 with NaOH solution.

[0034] The LB liquid culture medium formulation in the following examples is as follows: 10g tryptone, 5g yeast extract, 10g NaCl, distilled water to make up to 1L, and pH adjusted to 7.0-7.2.

[0035] The formula for inorganic phosphorus medium is as follows: 10g glucose, 0.5g (NH4)2SO4, 0.5g yeast powder, 0.3g NaCl, 0.3g MgSO4, 0.3g KCl, 0.03g FeSO4, 0.03g MnSO4, 5g Ca3(PO4)2, 15g agar, and distilled water to a final volume of 1L. Sterilize at 115℃ for 30 minutes.

[0036] The formula for the organophosphorus culture medium is as follows: 10g glucose, 0.5g (NH4)2SO4, 0.5g yeast powder, 0.3g NaCl, 0.3g MgSO4, 0.3g KCl, 0.03g FeSO4, 0.03g MnSO4, 0.2g lecithin, 1g CaCO3, 15g agar, and distilled water to a final volume of 1L. Sterilize at 115℃ for 30 minutes.

[0037] The nitrogen-fixing medium formula is as follows: KH2PO4 0.2g, MgSO4 0.2g, NaCl 0.2g, CaCO3 5g, mannitol 10g, CaSO4 0.1g, agar 15g, distilled water to make up to 1L, sterilize at 121℃ for 15min.

[0038] The formula for potassium-solubilizing medium is as follows: 5g sucrose, 2g Na2HPO4, 0.5g MgSO4, 0.005g FeCl3, 0.1g CaCO3, 1g potassium feldspar powder (300 mesh), 15g agar, and distilled water to make up to 1L. Sterilize at 115℃ for 30min.

[0039] The formulation of the medium for producing 3-indoleacetic acid (IAA) is as follows: 1.15 g K2HPO4, 20 g peptone, 15 mL glycerol, 0.1 g L-tryptophan, 1.5 g MgSO4, and distilled water to a final volume of 1 L. Sterilize at 115 °C for 30 min.

[0040] The formulation of the culture medium for producing extracellular polymeric substances (EPS) is as follows: 20g sucrose, 0.2g K2HPO4, 0.5g KH2PO4, 100g NaCl, 0.5g MgSO4, 3g yeast powder, and distilled water to a final volume of 1L. Sterilize at 121℃ for 15min.

[0041] Example 1

[0042] Isolation and screening of Bacillus licheniformis BL-C15

[0043] Ten saline-alkali soil samples were collected from Wuyuan County, Inner Mongolia; Haixing County, Cangzhou, Hebei; and Huanghua City, Cangzhou, Hebei. The samples were placed in pre-sterilized bags, cooled with ice packs, and transported back to the laboratory, where they were stored at 4°C. Salt- and alkali-tolerant microorganisms were screened using LB medium with a salt content of 3 wt% and a pH of 9. The specific steps included: weighing 5 g of the soil sample and adding it to a conical flask containing 45 mL of sterile water, shaking at 200 rpm for 30 min to obtain a soil mixture. The soil mixture was then diluted using a gradient, with a concentration gradient of 10... -4 10 -5 and 10 -6 Soil mixtures were prepared by spreading 100 μL of each solution onto saline-alkali LB agar (3 wt% NaCl, pH 9) for the isolation of salt- and alkali-tolerant microorganisms, with three plates per dilution. The plates were inverted and incubated at 28°C for 72 h. Colonies of different morphologies were picked and subjected to three streak purification tests. The purified strains were stored in 50% glycerol at -80°C for later use. Ten highly efficient salt- and alkali-tolerant microorganisms were purified using saline-alkali LB agar and named C-1, C-3, C-8, C-14, BL-C15, C-31, C-35, C-41, C-55, and L1-2.

[0044] Example 2

[0045] Growth-promoting effects of salt- and alkali-tolerant strains

[0046] Ten bacterial strains obtained from Example 1 were activated on LB agar plates. The activated strains were then inoculated into LB liquid medium (10g tryptone, 5g yeast extract, 10g NaCl, and distilled water to a final volume of 1L, pH adjusted to 7.0-7.2) and incubated at 28°C for 24 hours. The bacterial suspension was centrifuged at 10,000 rpm for 10 minutes, the supernatant was discarded, and 10 mL of sterile water was added and shaken to resuspend the bacterial cells. The suspension was then centrifuged again at 10,000 rpm for 10 minutes, the supernatant was discarded, and the bacterial cells were resuspended in sterile water and the OD was adjusted. 600 The bacterial solution was obtained by setting the concentration to 0.1. Ten uniformly sized wheat seeds were evenly placed in sterile petri dishes lined with double-layered filter paper. 5 mL of bacterial solution was added to each dish, followed by a layer of sterile vermiculite rinsed with water. 5 mL of water with a NaCl concentration of 1 wt% and a pH of 9 was then poured in. The dishes were cultured at 25℃ under alternating light and dark conditions for 12 h / 12 ​​h. After one week, the plant height, root length, and fresh weight of the wheat were measured, and the growth promotion rate was calculated (a wheat growth plate from the same batch with an equal volume of water instead of bacterial solution served as a blank control). The specific growth promotion effects of different bacterial strains on wheat are shown in Table 1. The wheat growth of strain BL-C15 and the control group are shown in Table 1. Figure 1 As shown.

[0047] Table 1. Growth-promoting effects of salt- and alkali-tolerant growth-promoting strains on wheat.

[0048] strain Plant height growth rate Root length growth rate Fresh weight growth rate C-1 12.52％ -0.7％ 11.11％ C-3 0.92％ -2.3％ 5.56％ C-8 5.49％ 2.14％ 5.56％ C-14 12.33％ 7.02％ 11.15％ BL-C15 16.42％ 21.95％ 25％ C-31 -7.91％ 2.92％ 5.56％ C-35 5.58％ 8.82％ 13.89％ C-41 8.95％ 2.61％ 16.67％ C-55 18.83％ 10.49％ 11.08％ L1-2 2.25％ 8.18％ 11.13％

[0049] As shown in Table 1, under the above saline-alkali conditions, strain BL-C15 has the best growth-promoting effect on wheat, so this strain was selected as the subject of subsequent research.

[0050] Example 3

[0051] Determination of the salt and alkali tolerance range of salt- and alkali-tolerant strain BL-C15

[0052] The selected salt- and alkali-tolerant strain BL-C15 was inoculated into LB agar plates with salt concentration (NaCl concentration) gradients of 3 wt%, 5 wt%, and 10 wt%, and pH gradients of 9, 10, 11, and 12, respectively. The plates were incubated at 28°C for 48 h. The growth of the strain on LB plates at different salt concentrations and pH values ​​was observed to determine its salt and alkali tolerance range. The results showed that the strain could still grow well on media with a salt concentration of 10% and a pH of 12, indicating that it has strong salt and alkali tolerance, especially strong alkali tolerance, and can grow normally in highly alkaline environments. The growth images of strain BL-C15 in media with a salt concentration of 10 wt% and a pH of 12 are shown below. Figure 2 (a) and Figure 2 As shown in (b).

[0053] Example 4

[0054] Identification of Bacillus licheniformis BL-C15

[0055] Morphological identification:

[0056] Strains BL-C15 were removed from the low-temperature freezer and inoculated onto LB solid medium. They were incubated at 28°C for 48 hours, and colony growth was observed. Their morphological characteristics are as follows: Figure 3 As shown, this strain grows relatively quickly, with flat colonies, irregular edges, and a white, opaque appearance.

[0057] Molecular biological identification:

[0058] The activated strain BL-C15 was inoculated into LB liquid medium and cultured in a shaker at 28°C for 24 h. The resulting bacterial culture was then sent to Sangon Biotech (Shanghai) Co., Ltd. for amplification and sequencing using primer pairs gyrB-FUP-1 (5′-GAAGTCATCATGACCGTTCTGCAYGCNGGNGGNAARTTYGA-3′, SEQ ID NO.1) and gyrB-RUP-2r (5′-AGCAGGGTACGGATGTGCGAGCCRTCNACRTCNGCRTCNGTCAT-3′, SEQ ID NO.2), yielding the 16S rDNA sequence (as shown in SEQ ID NO.3). The sequencing results were analyzed using BLAST at NCBI. The BLAST results showed that the BL-C15 strain shared 99% similarity with the gyrb gene sequence of Bacillus licheniforms. The phylogenetic tree of BL-C15 is shown below. Figure 4 As shown.

[0059] Based on the above characteristics, strain BL-C15 was identified as belonging to *Bacillus licheniforms*. This strain BL-C15 was deposited on November 25, 2024, at the China General Microbiological Culture Collection Center (CGMCC), with accession number CGMCC No. 32787, located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, and its taxonomical name is *Bacillus licheniforms*.

[0060] The reaction system used for PCR amplification was as follows: 94℃ for 5 min; 94℃ for 30 s; 55℃...

[0061] 45s, 72℃, 1min, 30 cycles in total; 72℃, 10min.

[0062] Example 5

[0063] This example tests the growth-promoting properties of strain BL-C15. The test methods for each performance are as follows:

[0064] The strain BL-C15 obtained in Example 1 was streaked onto LB solid medium and incubated upside down at 28°C for 1–3 days. The activated strain was then inoculated into 50 mL of LB liquid medium and incubated on a shaker at 28°C for 24 h to obtain the bacterial suspension required for the experiment. The following tests were performed using this bacterial suspension:

[0065] (1) Inorganic phosphorus solubilization ability test: 5 μL of the obtained bacterial solution was inoculated onto an inorganic phosphorus medium and cultured at 28℃ for 7 days. The appearance of a clear zone around the strain indicated that the strain had the ability to solubilize inorganic phosphorus. The results are shown in Table 2 and... Figure 5 As shown.

[0066] (2) Test of organophosphate solubilization: 5 μL of the obtained bacterial solution was inoculated onto an organophosphate medium and cultured at 28°C for 7 days. No turbidity spots appeared around the strain, indicating that the strain does not have the ability to solubilize organophosphates.

[0067] (3) Indole-3-acetic acid (IAA) production capacity test: The bacterial culture was inoculated into IAA medium at a 5% inoculum size and cultured on a shaker at 28°C for 48 h. After centrifugation at 10000×g for 10 min, 1 mL of the supernatant was taken and mixed with 2 mL of Salkowski reagent (15 mL concentrated sulfuric acid, 25 mL double-distilled water, and 0.75 mL 0.5 mol / L FeCl3). After incubation in the dark for 30 min, the IAA medium inoculated with the bacterial culture turned pink, while the IAA medium without the bacterial culture (referred to as the control group CK) remained colorless, indicating that the strain has the ability to produce IAA. The results are shown in Table 2 and... Figure 6 As shown.

[0068] (4) Test of extracellular polymeric substance (EPS) production capacity: The strain was inoculated into EPS medium at a 5% inoculum and cultured in a shaker at 28°C for 48 h. 10 mL of culture solution was centrifuged at 10000 r / min for 10 min, the supernatant was removed, the bacterial cells were dried and weighed, and 30 mL of 95% ethanol was added to the supernatant for alcohol precipitation. The mixture was placed in a refrigerator at 4°C overnight, and the mixture was centrifuged at 10000 r / min for 10 min. The supernatant was removed, the precipitate was dried and weighed, and the ratio of EPS dry weight to bacterial dry weight was the EPS yield of the strain. The results are shown in Table 2, indicating that the strain can produce extracellular polymeric substances (EPS) with a yield of 2.38 g / g.

[0069] (4) Potassium solubilization ability test: 5 μL of bacterial culture was inoculated onto potassium solubilization medium and cultured at 28℃ for 7 days. The appearance of a clear zone around the strain indicated that the strain had potassium solubilization ability. The results are shown in Table 2.

[0070] (5) Nitrogen fixation capacity test: 5 μL of bacterial solution was inoculated on nitrogen fixation medium and cultured at 28℃ for 7 days. It was observed that the strain did not grow, indicating that the strain does not have nitrogen fixation capacity.

[0071] Table 2 Summary of the growth-promoting characteristics of strain BL-C15

[0072] Types of growth-promoting properties Growth-promoting effect Potassium solubilization +(1.98) Nitrogen fixation - Degradation of inorganic phosphorus (D / d) +(1.21) Degradation of organophosphates (D / d) - IAA production (ug / mL) +(7.06) EPS production (g / g) +(2.38)

[0073] Note: In Table 2, "+" indicates that the function is available; "-" indicates that the function is not available.

[0074] As shown in Table 2, strain BL-C15 has the ability to solubilize potassium, inorganic phosphorus, produce IAA and EPS. These abilities ensure the salt tolerance, alkali tolerance and growth-promoting properties of this strain.

[0075] Example 6

[0076] This example investigates the growth-promoting effect of strain BL-C15 on wheat in saline-alkali soil.

[0077] In the following pot experiment, the saline-alkali soil used was from Inner Mongolia. Specific physicochemical properties are shown in Table 3.

[0078] Table 3. Basic physicochemical properties of saline-alkali soil used in pot experiments.

[0079]

[0080] Preparation of bacterial suspension: BL-C15 strain was streaked onto LB solid medium for activation and cultured for 48 h. Bacterial growth was picked and inoculated into 100 mL of sterilized LB liquid medium and cultured at 28 °C and 200 rpm / min for 12 h on a shaker. The bacterial suspension was centrifuged at 10,000 rpm for 10 min, the supernatant was discarded, and 10 mL of sterile water was added and shaken to resuspend the bacterial cells. The suspension was then centrifuged again at 10,000 rpm for 10 min, the supernatant was discarded, and the bacterial cells were resuspended in sterile water and the OD was adjusted. 600 The concentration was 0.1, and a bacterial suspension was obtained.

[0081] A simulated experiment was conducted in flowerpots approximately 12 cm in diameter and 12 cm in height. The bacterial suspension was mixed with the tested saline-alkali soil (ratio: 10 kg saline-alkali soil: 100 mL bacterial suspension). A control group (CK) was prepared with an equal amount of sterile water. Cleaned, uniformly sized wheat seeds were evenly planted in each flowerpot, 20 seeds per pot. After 4 weeks of cultivation, the plant height, root length, fresh weight, and chlorophyll content of the wheat were measured. The test results are shown in Table 4. Growth conditions are as follows: Figure 7 As shown.

[0082] Table 4 Effects of strain BL-C15 on wheat growth

[0083] Different treatments Plant height(mm) Root length (mm) Fresh weight (g) chlorophyll CK 197.23±15.48b 134.07±11.35b 0.20±0.02c 3.94±0.35b BL-C15 212.78±9.61a 143.39±13.16b 0.22±0.02b 4.00±0.31b

[0084] Note: The above data are expressed as "mean ± standard deviation (SD)", and different lowercase letters indicate differences at the p < 0.05 level.

[0085] Example 7

[0086] This embodiment investigates the effect of strain BL-C15 on the growth of sunflower in saline-alkali soil. The experimental site was Wuyuan County, Bayannur, Inner Mongolia. The soil texture is shown in Table 5.

[0087] Table 5. Basic physicochemical properties of soil from the test plots

[0088]

[0089] Preparation of saline-alkali soil amendment product (microbial inoculant): Bacterial strain BL-C15 was activated by streaking on LB solid medium and cultured for 48 hours. The bacterial growth was then inoculated into 100 mL of sterilized LB liquid medium and cultured at 28℃ and 200 rpm / min for 24 hours. This seed culture was then expanded until over 80% of the culture produced spores, yielding BL-C15 bacterial suspension. The resulting suspension was adsorbed with biochar to prepare a microbial inoculant with a viable count of 200 million / g. Before land cultivation, the obtained microbial inoculant was evenly applied to the soil surface at a rate of 100 kg / mu, followed by tilling and planting of sunflowers. Simultaneously, sunflowers were planted in the same manner in soil without the microbial inoculant (as a control group). The growth of sunflowers, soil conductivity, and pH in the saline-alkali soil treated with the microbial inoculant and the control group are shown in Table 6. It can be seen that, compared with the control group, the application of microbial inoculants can significantly promote the growth of sunflowers, increasing the stem diameter, plant height and yield by 38.10%, 28.12% and 32.59% respectively. At the same time, it can also reduce the soil electrical conductivity and pH, indicating that this strain can not only promote the growth of sunflowers, but also improve saline-alkali soil.

[0090] Table 6. Effects of microbial inoculants containing BL-C15 on sunflower growth and soil physicochemical properties.

[0091]

[0092] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A Bacillus licheniformis (BL-C15) strain characterized in that, Bacillus licheniformis ) BL-C15, characterized in that, Bacillus licheniformis deposited at China General Microbiological Culture Collection Center on November 25, 2024, with the preservation number of CGMCC No. 32787, and the preservation address of No. 3, Beichen West Road, Yard 1, Chaoyang District, Beijing.

2. The bacillus licheniformis BL-C15 of claim 1 is applied as a growth-promoting product for wheat or oil sunflower.

3. The bacillus licheniformis BL-C15 of claim 1 is applied as a product for degrading inorganic phosphorus.

4. The bacillus licheniformis BL-C15 of claim 1 is applied as a product for releasing potassium.

5. The bacillus licheniformis BL-C15 of claim 1 is applied in the production of indole-3-acetic acid IAA.

6. The bacillus licheniformis BL-C15 of claim 1 is applied in the production of extracellular polymeric substance EPS.

7. Use of Bacillus licheniformis BL-C15 according to claim 1 as a product for saline soil amelioration, characterized in that, The pH of the saline-alkali soil is 8-12.

8. The use of Bacillus licheniformis BL-C15 according to claim 7 as a saline-alkali soil improvement product, characterized in that, The salt content of the saline-alkali soil is not less than 0.1 wt%.

9. A microbial inoculant, characterized in that, The bacillus licheniformis BL-C15 of claim 1 is included.

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