Phosphorus-solubilizing bacteria and application thereof in phosphate solubilizing

Abstract

The invention provides a phosphate solubilizing bacterium and application of the phosphate solubilizing bacterium in phosphate solubilizing. The phosphate solubilizing bacterium is bacillus subtilis WG0313, the preservation unit is Guangdong Microbial Culture Collection Center, the preservation date is June 6, 2025, and the preservation number is GDMCC NO.66470. The phosphate solubilizing bacterium can be applied to phosphate solubilizing. The strain can convert insoluble phosphorus into soluble phosphorus up to 127.59 mg / L, is remarkably superior to an existing phosphorus-solubilizing strain, has good environmental adaptability and efficient phosphorus conversion capacity, and can effectively improve the content of soluble phosphorus in soil, reduce the use of chemical phosphate fertilizer, promote plant growth and reduce the risk of environmental pollution. The strain provides an important resource for developing a special bio-organic fertilizer suitable for rubber tree planting, and has important significance for promoting green and sustainable development of agriculture.

Description

Technical Field

[0001] This invention belongs to the field of biotechnology and relates to a phosphate-solubilizing bacterium and its applications in phosphate solubilization. Background Technology

[0002] Phosphorus is a key nutrient element for plant growth, but most phosphorus in the soil exists in insoluble forms (such as iron phosphate, aluminum phosphate, and calcium phosphate), making it difficult for plants to directly absorb and utilize. In traditional agriculture, excessive application of chemical phosphate fertilizers not only leads to soil compaction and phosphorus precipitation but also causes non-point source pollution problems such as eutrophication of water bodies through surface runoff and groundwater infiltration. Studies have shown that the utilization rate of chemical phosphate fertilizers in the current season is only 15%-25%, and the remaining phosphorus easily combines with metal ions such as calcium, aluminum, and iron in the soil to form insoluble compounds, further exacerbating the decline in soil fertility. Therefore, developing environmentally friendly alternative technologies to reduce dependence on chemical phosphate fertilizers has become an urgent need for sustainable agricultural development.

[0003] Phosphate-solubilizing microorganisms (PSMs) have become an important means of solving the aforementioned problems due to their ability to convert insoluble phosphorus into soluble phosphorus. Existing phosphate-solubilizing bacteria mainly include bacteria (such as Bacillus and Pseudomonas) and fungi (such as Penicillium and Aspergillus). Their phosphorus-solubilizing mechanism mainly involves secreting organic acids (such as lactic acid and malic acid), enzymes (such as phytase and phosphatase), and complexing agents to react with metal ions in the soil and release soluble phosphorus. However, existing phosphate-solubilizing bacteria generally suffer from low phosphorus-solubilizing efficiency and poor environmental adaptability, and there is a lack of highly efficient strains specifically for certain soil types (such as rubber plantation soils).

[0004] In recent years, some studies have reported the application potential of highly efficient phosphate-solubilizing bacteria. For example, the Burkholderia T4 strain screened by Dai Shenyan et al. showed an AlPO4 solubility of 334.2 mg / L, while the effective phosphorus content of the rhizosphere phosphate-solubilizing bacteria isolated by Xue Yi et al. was only 60.35 mg / L. Nevertheless, these strains still face limitations in practical applications, such as large fluctuations in phosphate-solubilizing activity and insufficient tolerance to salt concentration and pH. Furthermore, rubber plantation soils, due to long-term monoculture and nutrient depletion, often exhibit phosphorus deficiency, necessitating the development of specialized strains with strong adaptability and outstanding phosphate-solubilizing capabilities. Therefore, current technology urgently needs a highly efficient and stable phosphate-solubilizing bacterium that can maintain high phosphate-solubilizing activity under complex environmental conditions (such as specific pH and salt concentrations) and is suitable for special soil types such as rubber plantations. Summary of the Invention

[0005] The purpose of this invention is to provide a phosphate-solubilizing bacterium and its applications in phosphate solubilization, thereby addressing the problems it aims to solve.

[0006] To solve the above-mentioned technical problems, the present invention provides a phosphate-solubilizing bacterium, characterized in that the phosphate-solubilizing bacterium is Bacillus subtilis WG0313, deposited by Guangdong Provincial Center for Microbial Culture Collection, deposited on June 6, 2025, with accession number GDMCC NO.66470.

[0007] The present invention also provides the application of a phosphate-solubilizing bacterium in the preparation of a microbial preparation with phosphate-solubilizing activity.

[0008] More preferably, the application of the phosphate-solubilizing bacteria in the preparation of phosphate-solubilizing bacterial agents for bio-organic fertilizer.

[0009] More preferably, the bio-organic fertilizer phosphorus-solubilizing agent is a special bio-organic fertilizer phosphorus-solubilizing agent for rubber tree planting.

[0010] The present invention also provides a microbial preparation with phosphate-solubilizing activity, comprising the above-mentioned phosphate-solubilizing bacteria.

[0011] Compared with the prior art, the present invention has the following beneficial effects:

[0012] Firstly, the phosphate-solubilizing bacteria of the present invention, under optimized conditions (inoculum size 3.12%, initial pH 7.1, salt concentration 9.2 g / L), can convert insoluble phosphorus into soluble phosphorus, with a maximum content reaching 127.59 mg / L. Compared with other reported phosphate-solubilizing strains, the highest soluble phosphorus content is 63.93 mg / L. Therefore, the phosphate-solubilizing bacteria of the present invention exhibit significantly higher phosphate-solubilizing efficiency.

[0013] Secondly, by optimizing conditions such as inoculum size, pH, and salt concentration, the phosphate-solubilizing bacteria of this invention exhibit good environmental adaptability. This strain maintains high phosphate-solubilizing activity over a wide range of salt concentrations and pH values, with optimal phosphate solubilization, especially under neutral conditions (pH 7.1). This makes it suitable for various soil types, particularly rubber plantation soils.

[0014] Thirdly, the application of phosphate-solubilizing bacteria in this invention can effectively increase the content of soluble phosphorus in the soil, thereby enhancing the efficiency of crop phosphorus absorption and utilization. Studies have shown that the rational use of phosphate-solubilizing microorganisms can reduce the application of chemical phosphate fertilizers by about 50%, while maintaining or increasing crop yields, contributing to the greening and sustainable development of agricultural production.

[0015] Fourth, research shows that the phosphate-solubilizing bacteria isolated from rubber plantation soil is a high-quality strain resource, providing a foundation for the development of special bio-organic fertilizer for rubber trees. This strain can not only improve soil structure and fertility, but also enhance the stress resistance and yield stability of rubber trees. Attached Figure Description

[0016] Figure 1 It is a primary screening strain on phosphorus-containing plates (a, organic phosphorus medium, dilution gradient 10). -5 b, Inorganic phosphorus medium, dilution gradient 10 -7 );

[0017] Figure 2 These are the soluble phosphorus content, cell phosphorus content, and total phosphorus content (mg / L) of six phosphate-solubilizing bacteria strains.

[0018] Figure 3 Used to demonstrate the correlation between soluble phosphorus content and D / d value in phosphate-solubilizing bacteria culture medium;

[0019] Figure 4 These are morphological images of strain PSM-08 (a, colony morphology of strain PSM-08; b, morphology of strain PSM-08 under a microscope (10*20)).

[0020] Figure 5 This is the phylogenetic tree of the 16S rDNA of strain PSM-08;

[0021] Figure 6 Used to demonstrate the effect of inoculum size on phosphorus solubilization of strain PSM-08;

[0022] Figure 7 Used to demonstrate the effect of initial pH on phosphorus solubilization of strain PSM-08;

[0023] Figure 8 This was used to demonstrate the effect of salt concentration on phosphorus solubility in strain PSM-08. Detailed Implementation

[0024] The following detailed description, in conjunction with the accompanying drawings and specific embodiments, provides a further detailed explanation of the phosphate-solubilizing bacterium proposed in this invention and its applications. The advantages and features of this invention will become clearer from the following description. It should be noted that the drawings are all in a very simplified form and use non-precise proportions, used only to facilitate and clarify the illustration of the embodiments of this invention. The same or similar reference numerals in the drawings represent the same or similar parts.

[0025] Example

[0026] 1. Screening and Phosphate-Solubilizing Capacity Determination of Phosphate-Solubilizing Bacteria

[0027] 1.1 Soil sampling in rubber plantations

[0028] Using GPS coordinates, the specific location of the high-yield and high-efficiency rubber demonstration base project of the Chinese Academy of Tropical Agricultural Sciences is located in Baodao New Village, Dacheng Town, Danzhou City, Hainan Province. The center of the plot is located at 109.48391 degrees latitude and longitude and 19.539468 degrees north latitude. Soil samples were obtained using a multi-point uniform sampling method. Each sample was kept with a wet weight of 300-500g and a sampling depth of 10-30cm. The samples were placed in sterile sealed bags and numbered in a standardized manner. All samples were quickly transported to the laboratory for the isolation and culture of phosphate-solubilizing microorganisms.

[0029] 1.2 Culture medium

[0030] The culture media required for the isolation and screening test of phosphate-solubilizing bacteria include: Monkina organic / inorganic phosphorus medium, slant agar, beef extract peptone, starch, lead acetate medium, NBRIP, and LB liquid medium.

[0031] 1.3 Initial screening of phosphate-solubilizing bacteria

[0032] 10g of collected soil was placed in a 250ml sterile Erlenmeyer flask, and 90ml of sterile water was added. After shaking at 200r / min for 30min, the rhizosphere soil turbidity was taken on a clean bench and serially diluted with sterile water to obtain soil solutions with different dilution gradients of 10⁻¹, 10⁻², 10⁻³, 10⁻⁴, 10⁻⁵, 10⁻⁶, and 10⁻⁷. A 10⁻⁶ concentration of each solution was then transferred to the flask. -5 10 -6 and 10 -7 20 μL of soil suspensions were evenly spread onto 90 mm diameter organic and inorganic phosphorus separation medium plates, with three biological replicates for each concentration gradient. The plates were inverted and incubated at 28°C for 3–5 days, continuously observing the formation of phosphate-solubilizing zones. Single colonies with diverse morphologies and clearly defined phosphate-solubilizing zones were selected and purified multiple times using the streak plate method until uncontaminated pure strains were obtained. The clear zone method was used to preliminarily assess the phosphate-solubilizing effect, with the size of the phosphate-solubilizing zone indicating the effectiveness of the phosphate-solubilizing bacteria. Single colonies were picked up with an inoculation loop and transferred to slant agar plates until colonies grew, then stored at 4°C for later use.

[0033] 1.4 Secondary screening of phosphate-solubilizing bacteria

[0034] The strains initially selected in section 2.2.3 were inoculated into NBRIP liquid medium, with sterilized but uninoculated NBRIP liquid medium used as a blank. The cultures were incubated for 6 days at 30°C in a shaker at 200 rpm. After 6 days of fermentation, 1 mL of the shaken culture was centrifuged at 10000 rpm for 10 min for solid-liquid separation. The soluble phosphorus content in the supernatant was quantitatively analyzed using the molybdenum-antimony colorimetric method, and the phosphorus content of the precipitated bacterial cells was determined using the vanadium-molybdenum-antimony colorimetric method. Each experimental treatment was performed in triplicate to ensure data reliability.

[0035] 2. Strain Identification

[0036] 2.1 Morphological observation of the strain

[0037] Phosphate-solubilizing strains with strong phosphate-solubilizing ability were inoculated into beef extract peptone medium. After incubation at 28°C for 2–3 days, the colony morphology was carefully observed, including colony outline, surface stickiness, transparency, raised state, and edge structure.

[0038] 2.2 Detection of physiological and biochemical characteristics of the strain

[0039] To systematically explore the physiological and biochemical characteristics of the tested strains, this study used six experimental methods, including catalase detection, starch hydrolysis analysis, methyl red reaction test, Volta-Pr test, hydrogen sulfide generation identification, and gelatin liquefaction determination, to comprehensively characterize their physiological and biochemical features. The specific experimental procedures were based on Wang Wenjing's method for screening phosphate-solubilizing bacteria in the rhizosphere of soybean.

[0040] 2.3 Gene Sequencing

[0041] The selected highly active phosphate-solubilizing strains were subjected to 16S rDNA sequencing analysis and sent to Shanghai Sangon Biotech Co., Ltd. for 16S rDNA sequencing. A phylogenetic tree was constructed to determine the species and genus.

[0042] 2.4 Effects of inoculum size, initial pH, and salt concentration on phosphorus solubilization by the strain

[0043] The effect of inoculum size on phosphorus solubility was investigated by inoculating the cultured bacterial suspension into 250 mL Erlenmeyer flasks containing 100 mL of NBRIP liquid medium at inoculation ratios of 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, and 4%. The effect of initial pH and salt concentration on phosphorus solubility was also investigated by inoculating the cultured bacterial suspension at a 2% inoculum size into 250 mL Erlenmeyer flasks containing 100 mL of NBRIP liquid medium at initial pH values ​​of 2, 3, 4, 5, 6, 7, 8, and 9, and NaCl concentrations of 3, 6, 9, 12, 15, 18, 21, and 24 g / L, respectively. The flasks were then incubated at 28°C on a shaker at 180 rpm for 3 days. Each inoculum size treatment was replicated in triplicate. After incubation, the soluble phosphorus content in the fermentation broth was determined using the molybdenum-antimony colorimetric method.

[0044] 2.5 Data Processing

[0045] Experimental data were processed using Microsoft Excel, and the results are presented as averages. SPSS 26.0 statistical software was used to perform one-way ANOVA and significance tests on soluble phosphorus content and bacterial phosphorus content using LSD (L), SNK (S), and Tukey's-b (K) tests (P<0.05). Origin 2024 software was used for plotting.

[0046] 3 Results and Analysis

[0047] 3.1 Initial screening of phosphate-solubilizing bacteria

[0048] Twenty-one strains with transparent phosphate-solubilizing zones were obtained by plate plating of bacterial cultures from three enrichment cultures on both organic and inorganic phosphorus media. Five strains were screened from the organic phosphorus medium, and 16 strains were isolated from the inorganic phosphorus medium. Among these, 12 strains exhibited distinct transparent zones (phosphate-solubilizing zones), meaning they possessed phosphate-solubilizing ability. Four of these strains were screened from the organic phosphorus medium, and eight were isolated from the inorganic phosphorus medium. These strains were numbered PSM-01 to PSM-08. Visual images of some of the screened colonies are shown below. Figure 1 .from Figure 1 -a indicates that phosphate-solubilizing bacteria exhibit small and indistinct colonies and phosphate-solubilizing zones on organic phosphorus plates. In contrast, from Figure 1-b indicates that the inorganic phosphorus screening medium, using ammonium sulfate as the nitrogen source and tricalcium phosphate as the phosphorus source, provides sufficient nutrition. Under these conditions, the colonies growing on the inorganic phosphorus screening plates are larger, and the phosphate-solubilizing zones are also more pronounced. This study precisely measured the colony diameter (d) and the diameter of the clear zone (D), and further calculated their ratio (D / d). Table 1 shows that strains PSM-01, PSM-02, PSM-08, PSM-09, PSM-10, and PSM-11 have relatively large D / d values, all greater than or equal to 2.6. This indicates that these six strains have strong phosphate-solubilizing ability and were used as starting strains for secondary screening.

[0049] Table 1. Colony diameter (d) and phosphate-solubilizing zone diameter (D) of phosphate-solubilizing bacteria and their ratio (D / d)

[0050]

[0051] Note: PSM-01 to PSM-04 are organic phosphorus culture media, and PSM-05 to PSM-12 are inorganic phosphorus culture media.

[0052] 3.2 Secondary screening of phosphate-solubilizing bacteria

[0053] 3.2.1 Determination of phosphorus content in fermentation broth of phosphorus-solubilizing bacteria after secondary screening

[0054] Six phosphate-solubilizing bacteria strains with a D / d value greater than 2.6 selected in the initial screening were used as the starting strains for secondary screening. The phosphorus content of the six phosphate-solubilizing bacteria was as follows: Figure 2 As shown. Since soil compaction in arable land is primarily caused by inorganic phosphorus deposits, which have a significant impact, it is more practically significant to focus on the study of inorganic phosphorus-degrading bacteria. From Figure 2 It can be seen that the PSM-08 strain has the highest content of soluble phosphorus in its culture medium, with soluble phosphorus content as high as 103.95 mg / L and total phosphorus content as high as 205.94 mg / L. Therefore, the dominant phosphorus-solubilizing strain was identified as PSM-08.

[0055] 3.2.2 Correlation between soluble phosphorus content in the culture medium of phosphate-solubilizing bacteria after secondary screening and the D / d value of phosphate-solubilizing bacteria after primary screening

[0056] Correlation analysis was performed on the soluble phosphorus content in the phosphate-solubilizing bacteria culture medium and the ratio of phosphate-solubilizing zone diameter (D) to colony diameter (d). The order of D / d values ​​for the six strains was PSM-08 > PSM-11 > PSM-10 > PSM-09 > PSM-01 > PSM-02. The results are as follows: Figure 3 As shown, the correlation coefficient R = 0.9362, P < 0.05, indicating a significant positive correlation between the soluble phosphorus content and the D / d value in the phosphate-solubilizing bacteria culture medium; that is, the higher the D / d value, the higher the soluble phosphorus content. Among them, strain PSM-08 showed the best performance.

[0057] 3.3 Identification of phosphate-solubilizing bacteria PSM-08

[0058] 3.3.1 Morphological and physiological-biochemical identification of strain PSM-08

[0059] After culturing strain PSM-08 on NBRIP solid medium plates for 2 days, the colony morphology is as follows: Figure 4 As shown in -a, the colony is round and opaque, milky white in color, with a smooth surface and obvious ridges. A distinct descaling zone is visible around the colony. Figure 4 -b represents the morphological characteristics of the strain under a microscope. It is Gram-positive, exhibits a rod-like shape under microscopic examination, and exists singly or in pairs. The strain possesses spore and pili structures but lacks flagella. The physiological and biochemical characteristics of strain PSM-08 are shown in Table 2.

[0060] Table 2 Physiological and biochemical characteristics of strain PSM-08

[0061]

[0062] Note: "+" indicates a positive reaction; "-" indicates a negative reaction.

[0063] 3.3.2 Identification results of the 16S rDNA gene of strain PSM-08

[0064] like Figure 5 As shown, strain PSM-08 shares over 99.9% sequence similarity with Bacillus subtilis (GenBank: NR027552), indicating the closest phylogenetic relationship. Based on the analysis of colony morphology, microstructure characteristics, and physiological and biochemical properties, strain PSM-08 was ultimately identified as Bacillus subtilis.

[0065] 3.3 Optimization of Phosphate-Solubilizing Conditions for PSM-08 Phosphate-Solubilizing Bacteria

[0066] 3.3.1 Effect of inoculum size on phosphorus solubilization of strain PSM-08

[0067] like Figure 6 As shown, strain PSM-08 exhibited certain phosphorus solubilization activity within an inoculum concentration range of 0.5%–4%, but the efficiency was lower at both ends. The suitable inoculum concentration for phosphorus solubilization was 2%–4%, with 3% being the optimal concentration, at which the soluble phosphorus content reached its highest value. Through regression model fitting calculations, the optimal inoculum concentration for phosphorus solubilization of strain PSM-08 was determined to be 3.12%. Analysis suggests that inoculum density significantly affects the physiological activity of strain PSM-08, regulating its phosphorus conversion capacity. The 3.12% inoculum concentration precisely matches the optimal growth requirements of this strain, thereby maximizing phosphorus solubilization efficiency.

[0068] 3.3.2 Effect of initial pH on phosphorus solubility of strain PSM-08

[0069] Depend on Figure 7 Data analysis revealed that when the initial pH of the NBRIP medium was low, the phosphorus solubility of strain PSM-08 was limited, resulting in a correspondingly low soluble phosphorus content. As the pH increased, the strain's phosphorus-solubilizing activity increased, reaching its peak at a neutral pH of 7. When the initial pH of the medium was maintained between 6.5 and 7.5, strain PSM-08 exhibited optimal phosphorus-solubilizing performance, maintaining a high soluble phosphorus yield. Regression model fitting calculations determined that the optimal initial pH for the strain to achieve the best phosphorus-solubilizing effect was 7.1. This phenomenon can be attributed to the regulatory effect of environmental pH on the intracellular enzyme activity of strain PSM-08: pH changes significantly affect the strain's phosphorus conversion efficiency by influencing bacterial metabolic pathways, altering organic acid secretion and the expression levels of phosphorus-solubilizing enzymes.

[0070] 3.3.3 Effect of salt concentration on phosphorus solubility of strain PSM-08

[0071] like Figure 8 As shown, when the salt concentration is below 9 g / L, the soluble phosphorus content in the system shows a significant increasing trend with increasing salt concentration, indicating that the phosphorus solubilization efficiency of strain PSM-08 is rapidly enhanced. However, when the salt concentration exceeds 9 g / L, further increases in salt concentration lead to a decrease in soluble phosphorus content, and the strain's phosphorus solubilization ability weakens accordingly. The soluble phosphorus content reaches its peak at a salt concentration of 9 g / L. Precise calculations using regression equations show that the optimal salt concentration for strain PSM-08 to achieve the best phosphorus solubilization effect is 9.2 g / L. Analysis suggests that changes in salt concentration can regulate the osmotic pressure balance of the strain's cells, thereby affecting cell membrane permeability. This change may promote the secretion of acidic metabolites and phosphorus-related enzymes, ultimately regulating its phosphorus solubilization ability.

[0072] 4 Discussion

[0073] The strain PSM-08 screened in this study was identified as Bacillus subtilis and was Gram-positive by Gram staining. This is consistent with the conclusion in "Isolation, Identification and Biological Characteristics Analysis of Bacillus subtilis from Ostrich in Southern Xinjiang," which identified Bacillus subtilis T4 and T9 as Gram-positive from fresh feces of African ostriches in southern Xinjiang. The soluble phosphorus content of the inorganic phosphorus strain PSM-08 was 103.95 mg / L. In the study "Screening and Antibacterial and Growth-Promoting Characteristics of Phosphate-Solubilizing Bacteria in the Rhizosphere of Desert Plants," six phosphate-solubilizing bacteria were successfully screened from the rhizosphere of Caragana korshinskii, a desert plant, using calcium phosphate as the sole inorganic phosphorus source. The highest soluble phosphorus content in the culture medium reached 63.93 mg / L. In comparison, the soluble phosphorus content of strain PSM-08 in this experiment was 40.02 mg / L higher than this value. Furthermore, in the study "Screening and Phosphorus-Solubilizing Characteristics of Highly Efficient Phosphorus-Solubilizing Bacteria in the Rhizosphere of Camellia oleifera," Burkholderia davidii was isolated from the rhizosphere soil of Camellia oleifera, with an available phosphorus content of 60.35 mg / L in its culture medium. In the study "Phosphorus-Solubilizing Conditions and Characteristics of Phosphorus-Solubilizing Bacteria in the Root System of Bambusa textilis," Burkholderia latata was screened, achieving an available phosphorus content of 65.67 mg / L in a culture medium with calcium phosphate as the phosphorus source. Compared with the above results, strain PSM-08 exhibits a significant advantage in phosphorus-solubilizing ability.

[0074] 4.1 Effect of inoculum size on strain PSM-08

[0075] This study found that an inoculum size of 3.12% may reflect the balance between bacterial density and resource competition. Excessive inoculum size leads to overly high bacterial density, rapid depletion of nutrients such as carbon and nitrogen sources in the culture medium, intensified nutrient competition among bacteria, and excessive proliferation accompanied by the accumulation of harmful metabolic wastes (such as ammonia and ethanol). High-density bacteria may also lead to insufficient dissolved oxygen, affecting aerobic respiration and energy metabolism, inhibiting bacterial activity, and thus reducing phosphorus solubility. Conversely, insufficient inoculum size may result in limited total secretion of organic acids, affecting phosphorus solubility.

[0076] 4.2 Effect of initial pH on strain PSM-08

[0077] The optimal initial pH for phosphorus solubilization of strain PSM-08 screened in this study was 7.1, which differs from the conclusion of Sun Ke et al. (2021) who screened phosphorus-solubilizing bacteria using burdock rhizosphere soil from Fengxian County, Xuzhou, and found an initial pH of 3.79 for strain PSM-5 (Bacillus subtilis). This discrepancy may be due to differences in strain specificity and laboratory conditions, such as improper use of the pH meter during the experiment. Excessively high pH (alkaline environment, pH > 8) can disrupt cell membrane stability, inhibit enzyme activity, leading to slow cell growth and insufficient biomass; excessively low pH (acidic environment, pH < 5) can cause a large influx of H+ into the cell, disrupting the transmembrane proton gradient, affecting energy metabolism, and even causing cell death, resulting in a decrease in soluble phosphorus content.

[0078] 4.3 Effect of salt concentration on strain PSM-08

[0079] The study results showed that the optimal salt concentration of strain PSM-08 (9.20 g / L) was close to that of strain Sun Ke (10.46 g / L). Excessive salt concentration led to cell dehydration, resulting in membrane damage, decreased energy metabolism efficiency, and restricted cell growth. Conversely, excessively low salt concentrations reduced ion transmembrane transport efficiency, decreased resistance to and adaptability to subsequent salt concentration fluctuations, and consequently lower soluble phosphorus content.

[0080] In this experiment, the goodness of fit of the three optimal conditions for phosphorus solubilization of strain PSM-08 was relatively low. The R² values ​​for inoculum size, initial pH and salt concentration were 0.7126, 0.8262 and 0.7566, respectively. This may be due to inaccurate measurement of the initial values ​​and insufficient fitting data points.

[0081] The above description is merely a description of preferred embodiments of the present invention and is not intended to limit the scope of the present invention in any way. Any changes or modifications made by those skilled in the art based on the above disclosure shall fall within the protection scope of the claims.

Claims

1. A strain of Phosphorus mobilizing bacteria, characterized in that, The phosphorus solubilizing bacteria is Bacillus subtilis WG0313, the preservation unit is Guangdong Microbial Culture Collection Center, the preservation date is June 6, 2025, and the preservation number is GDMCC NO.66470.

2. The use of a strain of bacteria of the genus Burkholderia according to claim 1, characterized in that, The application of the phosphorus solubilizing bacteria in the preparation of microbial agents with phosphorus solubilizing effect.

3. The use of a strain of bacteria of the genus Burkholderia according to claim 2, characterized in that, The application of the phosphorus solubilizing bacteria in the preparation of bio-organic fertilizer phosphorus solubilizing agents.

4. The use of a strain of bacteria of the genus Burkholderia according to claim 3, characterized in that, The bio-organic fertilizer phosphorus solubilizing agent is a special bio-organic fertilizer phosphorus solubilizing agent for rubber tree planting.

5. A microbial preparation having a phosphorus-solubilizing effect, characterized by, The phosphorus solubilizing bacteria of claim 1.

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