Acid-resistant aluminum strain bacillus paranthracis SK0, and application and product thereof

Abstract

This invention relates to the field of microbial technology, specifically to an acid-resistant aluminum strain. Bacillus paranthracis SK0 and its applications and products. An aluminum-resistant strain SK0, the taxonomic name of which is *Bacillus paramyophyte* (… Bacillus paranthracis SK0, deposited on April 28, 2026 at the Guangdong Provincial Center for Microbial Culture Collection, with accession number GDMCC 68181. This invention's strain... Bacillus paranthracis SK0 exhibits excellent acid and aluminum resistance, high aluminum removal efficiency, and also promotes growth, providing a sound biological basis for aluminum toxicity remediation and crop growth promotion. (Invented strain) Bacillus paranthracis SK0 can increase soil pH, further reduce the content of exchangeable aluminum, and enhance aluminum removal through extracellular bioprecipitation, thereby improving the remediation effect of aluminum toxicity.

Description

Technical Field

[0001] This invention relates to the field of microbial technology, specifically to an acid-resistant aluminum strain. Bacillus paranthracis SK0 and its applications and products. Background Technology

[0002] In recent years, soil acidification in my country has become increasingly serious due to multiple factors, including improper application of agricultural fertilizers and industrial acid rain pollution. Soil acidification not only harms crop growth and development to varying degrees, but may also indirectly affect human health through the food chain.

[0003] Currently, remediation technologies for aluminum toxicity in acidic soils mainly encompass chemical amendments, physical remediation, and bioremediation. While chemical amendments such as lime and dolomite can rapidly increase soil pH and reduce aluminum ion activity, they suffer from drawbacks including high dosage requirements, potential soil compaction, and disruption of soil microbial communities. Physical remediation technologies, on the other hand, are costly and complex, hindering large-scale application. In contrast, bioremediation technologies, with their environmental friendliness, low cost, and strong sustainability, have become a research hotspot in this field in recent years.

[0004] Therefore, screening for highly efficient acid- and aluminum-resistant strains with aluminum removal capabilities, and clarifying their application methods and remediation mechanisms, is of great practical significance for solving the problem of aluminum toxicity in sugarcane in acidic soils and promoting the sustainable development of the sugarcane industry.

[0005] Chinese Patent 119875907A discloses an agricultural *Pantotheca acuminata* strain ALC and its applications, with accession number CGMCC No. 31309. This *Pantotheca acuminata* strain can chelate active aluminum by producing citric acid, thereby reducing the active aluminum content in the soil. It can also produce phosphate to further reduce soil aluminum content, ultimately mitigating soil aluminum toxicity. A plant growth-promoting microbial fertilizer for aluminum-contaminated soil prepared based on this strain can reduce the stress of heavy metals on plants, promote plant growth, and improve soil fertility while remediating heavy metal-contaminated soil. Furthermore, there is a synergistic effect between strains, which can further improve the remediation efficiency of heavy metal-contaminated soil. This strain possesses functions such as phosphorus solubilization, potassium solubilization, citric acid production, indoleacetic acid (IAA) production, and siderophore production, and can tolerate 4 mM Al. 3+ Furthermore, this microorganism is characterized by rapid reproduction and indefinite propagation, reducing the frequency of application and avoiding secondary damage to the soil. It offers advantages such as low cost, ease of operation, resource conservation, and environmental protection, providing a new direction for soil aluminum toxicity improvement. After application, it can effectively alleviate soil aluminum toxicity, increase the content of available nitrogen, available phosphorus, and available potassium, and improve pH value, which is beneficial for promoting crop root growth.

[0006] Chinese Patent 118931753A discloses an agricultural Pseudomonas aeruginosa ADAL3-4 and its applications; the strain's preservation number is CGMCC No. 28603. This strain is effective against Al... 3+ The strain can tolerate concentrations above 1450 μM and possesses the ability to secrete auxin, 1-aminocyclopropane-1-carboxylic acid (ACC) deaminase, and siderophores, while also exhibiting phosphorus solubilization and nitrogen fixation functions. Hydroponic experiments showed that this strain can promote the growth of Arabidopsis thaliana, alfalfa, and maize, and enhance their resistance to aluminum stress. In summary, the *Pseudomonas aeruginosa* strain provided by this invention can effectively promote plant growth, providing important biomaterials and technical support for improving plant aluminum tolerance; its preparation as a biochar-loaded inoculant for phytoremediation is beneficial to crop growth and has good economic value.

[0007] Chinese Patent 117165470A discloses the application of agricultural Sphingomonas biochar immobilization inoculant, which can improve soil physicochemical properties and promote rice seed germination and seedling growth. The Sphingomonas strain used has the preservation number CCTCC NO:M 2023777 and possesses high IAA production capacity, responding to the rice seed germination process. After applying this inoculant, the total carbon content, total nitrogen content, available phosphorus content, electrical conductivity, microbial biomass carbon, and microbial biomass phosphorus in the paddy soil were significantly increased compared to the application of MSp2302 inoculant alone. Simultaneously, it increased rice seedling height, significantly promoting rice growth.

[0008] The invention screened a strain with excellent acid and aluminum resistance, high aluminum removal efficiency, and growth promotion function. The strain was identified as Bacillus paranthraciss SK0. There are currently no related reports on this. Summary of the Invention

[0009] The purpose of this invention is to provide an acid-resistant aluminum strain. Bacillus paranthracis SK0 and its applications and products.

[0010] To achieve the above-mentioned objectives, the technical solution of the present invention is as follows: An aluminum-resistant strain SK0, whose taxonomic name is *Bacillus paramyophyte* (… Bacillus paranthracis SK0 was deposited at the Guangdong Provincial Center for Microbial Culture Collection on April 28, 2026, with accession number GDMCC 68181; the 16S rRNA sequence of the aluminum-resistant strain SK0 is shown in SEQ ID NO 1.

[0011] The 16S rRNA sequence of the aluminum-resistant strain SK0 is as follows:

[0012] The present invention also provides a microbial agent, characterized in that the microbial agent comprises the acid-resistant aluminum strain SK0.

[0013] Furthermore, the bacterial count of the aluminum-resistant strain SK0 in the bacterial agent is 10. 9 -10 10 CFU / mL.

[0014] The present invention also provides the application of the acid-resistant aluminum strain SK0 or the bacterial agent in repairing aluminum toxicity and promoting crop growth.

[0015] The present invention also provides the application of the aluminum-resistant strain SK0 or the bacterial agent in reducing the absorption and accumulation of aluminum by plants and alleviating aluminum toxicity in sugarcane.

[0016] The present invention also provides the application of the acid-resistant aluminum strain SK0 or the bacterial agent in reducing the exchangeable aluminum content in soil, reducing the organically bound aluminum content in soil, increasing soil pH and organic matter content, or increasing sugarcane yield.

[0017] The present invention also provides the use of the acid-resistant aluminum strain SK0 or the bacterial agent in the preparation of products that remove aluminum from soil.

[0018] The present invention also provides the application of the acid-resistant aluminum strain SK0 or the bacterial agent in converting trivalent aluminum into organically bound aluminum.

[0019] Compared with the prior art, the present invention has the following advantages and technical effects: (1) The strain of the present invention Bacillus paranthracis SK0 exhibits excellent acid and aluminum resistance and high aluminum removal efficiency, while also possessing growth-promoting properties, providing a sound biological basis for aluminum toxicity remediation and crop growth promotion.

[0020] (2) Invented strain Bacillus paranthracis SK0 can increase soil pH, further reduce the content of exchangeable aluminum, and enhance aluminum removal through extracellular bioprecipitation, thereby improving the remediation effect of aluminum toxicity.

[0021] (3) This invention studies the strain through outdoor pot experiments. Bacillus paranthracis The effects of SK0 on the fertility of acidified sugarcane soil, the content of different forms of aluminum in the soil, and soil enzyme activity were investigated, and the results showed that the strain of this invention... Bacillus paranthracis Applying SK0 to acidified sugarcane soil may increase soil pH and CEC, enhance soil fertility, increase soil enzyme activity, and reduce soil active aluminum content, thus improving acidic soil. Simultaneously, it can alleviate sugarcane aluminum toxicity, increase sugarcane yield, and benefit crop growth.

[0022] Preservation Instructions Strain SK0, classified as Bacillus paramyxobolus. Bacillus paranthracis SK0 was deposited on April 28, 2026, at the Guangdong Provincial Center for Microbial Culture Collection; the deposit address is 5th Floor, Building 59, No. 100 Xianlie Middle Road, Guangzhou; the accession number is GDMCC 68181. Attached Figure Description

[0023] Figure 1 Colony morphology characteristics of the aluminum-resistant strain SK0; Figure 2 Phylogenetic tree of aluminum-resistant strain SK0; Figure 3 The aluminum removal performance of the aluminum-resistant strain SK0; Figure 4 A diagram showing the growth-promoting characteristics of the aluminum-resistant strain SK0; Figure 5 A biological scanning electron microscope image of the aluminum-resistant strain SK0; Figure 6 A control diagram showing the changes in soil aluminum speciation after inoculation with the aluminum-tolerant strain SK0. Figure 7 The effect of inoculating the aluminum-tolerant strain SK0 on soil improvement; Figure 8 Figure 1 shows the sugarcane plant height, dry weight, and aluminum accumulation in sugarcane under the treatment of the aluminum-tolerant strain SK0.

[0024] Key figures and descriptions: Figure 4 In the above, A represents nitrogen fixation capacity measurement (7d), B represents phosphorus solubility measurement (7d), C represents IAA production capacity measurement (7d), D represents iron carrier production capacity measurement (7d), and E represents alkali production capacity measurement (7d). Figure 6 In the study, CK was the control group, and SK0 was the treatment group inoculated with the aluminum-resistant strain SK0. Figure 7 In the table, A represents soil pH, B represents soil available nitrogen, C represents soil organic matter, D represents soil available phosphorus, and E represents soil available potassium. Figure 8 In the figure, A represents the sugarcane plant height, B represents the sugarcane dry weight, C represents the aluminum accumulation in different parts of the sugarcane, D represents the aluminum translocation coefficient in the root-stem region, E represents the aluminum translocation coefficient in the root-leaf region, and F represents the aluminum translocation coefficient in the stem-leaf region. Detailed Implementation

[0025] To make the technical means, creative features, achieved objectives, and effects of this invention readily understandable, the invention is further illustrated below with reference to specific embodiments. Other embodiments obtained by those skilled in the art based on the embodiments described herein without creative effort are all within the protection scope of this invention. Unless otherwise specified, the operating methods and equipment used in the following embodiments are conventional operating methods, and the materials and equipment used in each embodiment are the same.

[0026] 1. Strain screening and identification 1.1 Soil from which strains were isolated Soil samples were collected from a town in Chongzuo City, Guangxi Zhuang Autonomous Region. Topsoil samples from a depth of 5-20 cm were collected using a five-point sampling method. After thorough mixing, one sample was placed in a sterile centrifuge tube, placed in an ice box, and brought back to the laboratory for storage at -20℃ for screening for acid-aluminum resistant strains. Another sample was placed in a resealable bag, brought back to the laboratory, air-dried, and sieved. Sample preparation, determination of total aluminum content, exchangeable acid content, exchangeable aluminum content, and basic physicochemical properties in the soil were performed according to the "Methods for Soil Agricultural Chemical Analysis". The results are shown in Table 1.

[0027] Table 1 Soil physicochemical properties and aluminum content

[0028] 1.2 Culture medium LB nutrient agar: tryptone 10.0 g / L, yeast extract 5.0 g / L, sodium chloride 10.0 g / L, agar powder 15 g / L, pH 7.0 ± 0.2.

[0029] LB Broth: No agar powder added, otherwise the same as LB nutrient agar.

[0030] 1.3 Strains Isolation and Purification Sugarcane roots and their attached soil were placed together in a sterile Erlenmeyer flask containing 50 mL of sterile phosphate-buffered saline (PBS). Using sterile forceps, the roots were thoroughly shaken and stirred to remove the rhizosphere soil adhering to the root surface, collecting approximately 1 mm of rhizosphere soil as the test sample. The mixture was then incubated in a constant-temperature shaker at 28°C and 180 rpm for 2 hours to ensure thorough mixing of the rhizosphere soil and PBS. After shaking, the mixture was allowed to stand for 10 minutes. Then, 1 mL of the supernatant was added to a sterile centrifuge tube containing 9 mL of tryptone soybean broth (TSB).

[0031] The suspension was diluted to 10 using a gradient dilution method. -5 Then, 200 μL of soil dilution was mixed with 50 μL of Al. 3+ Solution (Al) 3 +A 5 mM solution was added to a 96-well plate and incubated at 37°C until microbial growth was visible in approximately 30% of the wells. Subsequently, the well-grown microbial suspension was plated onto LB agar and purified by streak plating 3–4 times to obtain single colonies.

[0032] One strain was obtained through screening and designated SK0.

[0033] 1.4 Preparation of Seed Culture of Strains The purified bacterial strain was picked and inoculated into 100 mL of sterilized LB broth. It was cultured at 28°C and 180 rpm with shaking for 1 day. The viable count was then adjusted to 1.16 × 10⁻⁶ cells / day using sterile water. 9 CFU / mL was used as the seed solution.

[0034] 1.5 Morphological observation of aluminum-resistant strain SK0 Referencing the *Manual of Systematic Identification of Common Bacteria* and the *Bergey's Manual of Bacterial Identification*, strain SK0 was inoculated onto LB nutrient agar and incubated at 28°C for 24 hours. Results are shown below. Figure 1 .

[0035] Depend on Figure 1 It can be seen that the colonies of strain SK0 are round, with a smooth and moist surface. They appear uniformly milky white under natural light, with a raised center and serrated edges.

[0036] 1.6 Scanning electron micrograph of aluminum-resistant strain SK0 The viable bacterial count in 20 ml was 1.16 × 10⁻⁶. 9 The seed culture (CFU / mL) was centrifuged at 2000 rpm for 10 min at 4 °C. After discarding the supernatant, 2.5% glutaraldehyde fixative, pre-cooled to 4 °C, was added to completely immerse the sample in the fixative. The sample was incubated overnight at 4 °C. The 2.5% glutaraldehyde fixative was discarded, and the sample was rinsed three times with 0.1 M phosphate buffer (pH 7.0) for 15 min each time. The sample was then fixed with 1% osmium tetroxide solution for 1-2 h. The osmium tetroxide waste solution was carefully removed, and the sample was rinsed three times with 0.1 M phosphate buffer (pH 7.0) for 15 min each time. The sample was then dehydrated with ethanol solutions of varying concentrations (30%, 50%, 70%, 80%, 90%, and 95%) for 15 min at each concentration, followed by two treatments with 100% ethanol for 20 min each. The sample was treated with a mixture of ethanol and isoamyl acetate (V / V = 1 / 1) for 30 min, followed by treatment with pure isoamyl acetate for 1 h or overnight. Critical point drying / freeze-drying was then performed. A coating was applied, and the samples were observed. The treated samples were then observed under a scanning electron microscope; the results are shown below. Figure 5 .

[0037] 1.7 Identification of 16S rRNA in the strain 16S rRNA identification of strain SK0: about 0.5 μg of single colony was picked into a 1.5 mL centrifuge tube for colony PCR. Universal bacterial primers 27F and 1492R were selected. The primer sequences are shown in Table 2. The PCR reaction system is shown in Table 3.

[0038] Table 2 16S rRNA primers

[0039] Table 3 PCR reaction system

[0040] The PCR program was as follows: 95℃ for 5 min; 95℃ for 30 s, 56℃ for 30 s, 72℃ for 1 min 30 s, for 25 cycles; 72℃ for 10 min.

[0041] Sanger sequencing was used to remove low-quality bases from both ends of the raw sequences to obtain clean sequences. The purified PCR products were then sequenced as 16S rRNA (sequence shown in SEQ ID NO 1). After sequencing, BLAST alignment was performed using NCBI, and sequence analysis was conducted using MEGA11 software to construct a phylogenetic tree. The constructed phylogenetic tree is shown below. Figure 2 As shown.

[0042] The 16S rRNA sequence of the selected strains was amplified, and the amplification results were spliced ​​to obtain the 16S rDNA sequence of the strains. The sequences were uploaded to NCBI for BLAST comparison and found that strain SK0 was similar to... Bacillus paranthracis The strain SK0 showed a 99% similarity to MCCC1A04098; therefore, based on sequence homology analysis, it was determined to be *Bacillus paramyxoides*, and was named accordingly. Bacillus paranthracis SK0.

[0043] 1.8 Strain SK0 against Al 3+ Its tolerance and its resistance to Al 3+ removal After activation, the strain was diluted to 10. -7 The strain SK0 was spread onto LB solid medium with aluminum concentrations of 0 mM, 2 mM, 4 mM, and 6 mM. It was incubated upside down at 28°C for 3 days. The results showed that strain SK0 could survive in 6 mM Al... 3+ The growth under these conditions indicates that SK0 can tolerate 6 mM Al 3+ .

[0044] The pH of LB broth medium was adjusted to 4.5, and after sterilization, AlCl3 was added to achieve an aluminum concentration of 1 mM. The broth medium was dispensed into 100 mL Erlenmeyer flasks, with 50 mL in each flask. Seed culture was inoculated into the medium at a 1% (v / v) ratio, and the mixture was incubated at 28°C with shaking at 180 rpm. Aluminum-containing medium inoculated with an equal volume of sterile water served as a blank control. At 1, 3, 5, and 7 days, 10 mL samples were collected, centrifuged at 12000 rpm for 10 min, and the supernatant was filtered through a 0.22 μm filter. The remaining aluminum content was determined using ICP-OES, and the aluminum removal rate was calculated. The results are shown below. Figure 3 .

[0045]

[0046] In the formula, R is the removal rate, C0 is the initial aluminum concentration, and C t The concentration of the supernatant after treatment.

[0047] Depend on Figure 3 It can be seen that strain SK0 can passivate aluminum by 83.67% on day 7, demonstrating good aluminum removal ability.

[0048] 1.9 Determination of the growth-promoting characteristics of the strain (1) Determination of nitrogen fixation capacity Will Bacillus paranthracis SK0 was inoculated into LB liquid medium and incubated at 28°C for 3 days. After incubation, the bacterial suspension was diluted to OD500 with sterile deionized water. 600 Value 1.0. 10 μL of bacterial suspension was spotted onto the surface of Ashby nitrogen-free solid medium. After spotting, the medium was inverted and incubated at 28°C for 3 days. The nitrogen-fixing capacity of the strain or bacterial community was determined based on the presence and size of the clear zone around the colony. Each treatment was performed in triplicate, with each experiment independently repeated three times.

[0049] Table 4. Ashby Nitrogen-Free Solid Culture Medium Formulation

[0050] (2) Determination of phosphorus solubility Prepare solid culture media containing organic and inorganic phosphorus, and place the strains... Bacillus paranthracis After SK0 is inoculated into LB liquid medium and activated, 10 μL of bacterial culture (OD) is taken. 600 =1.0) was applied to the surface of the culture medium, then sealed with sealing film and incubated upside down in an incubator for 3 days. Each group was repeated 3 times, and the phosphorus solubility of the strain and the bacterial community was determined by the molybdenum antimony colorimetric method.

[0051] Table 5. Organic phosphorus bacteria culture medium formulation

[0052] Table 6 Inorganic Phosphate Bacterial Culture Medium Formulation

[0053] (3) Determination of ability to produce indoleacetic acid (IAA) Take 10 μL of bacterial culture (OD) 600 =1.0) was inoculated into LB liquid medium containing L-tryptophan (200 mg / L) and cultured in the dark at 28°C and 180 rpm for 24 h. After culture, 200 μL of bacterial suspension was dropped onto a white ceramic plate, followed by an equal volume of Salkowski colorimetric solution (prepared by mixing 50 mL of 35% HClO4 and 1 mL of 0.5 mol / L FeCl3) and mixed thoroughly. The uninoculated LB medium containing L-tryptophan (200 mg / L) and the colorimetric solution served as a blank control. The reaction system was kept in the dark at room temperature for 30 min, and the color change of the solution was observed. A red color indicated that the strain had IAA secretion ability. Simultaneously, using the blank medium as a control, the absorbance was measured at 535 nm to plot an IAA standard curve and calculate the IAA yield (mg / L). Each treatment was performed in triplicate.

[0054] (4) Determination of iron production capacity Take 10 μL of bacterial culture (OD) 600 =1.0) was inoculated onto ferrophoric detection solid medium (CAS medium) and incubated at 28℃ for 48 h. If a distinct orange-yellow halo appears around the colony, it indicates that the strain or bacterial community has the ability to secrete siderophores. For quantitative determination, 2 mL of microbial culture supernatant was mixed with an equal volume of CAS detection solution, and the mixture was reacted in the dark for 1 h. The absorbance (As) was measured at 680 nm. The absorbance (Ar) of the blank medium after reacting with an equal volume of CAS detection solution was used as a control. Siderophore production is expressed as siderophore activity units (Su), calculated using the following formula:

[0055] Table 7 CAS Culture Medium

[0056] (5) Determination of alkali production capacity Take 10 μL of bacterial culture (OD) 600 =1.0) was inoculated into MR-VP liquid medium with a pH of 4.0 and cultured at 28°C with shaking at 180 rpm for 48 h. After the culture was completed, the final pH of the bacterial suspension was measured using a pH meter to evaluate the alkali-producing capacity of the strain or bacterial community.

[0057] Table 8 MR-VP Liquid Culture Medium Formulation

[0058] See results Figure 4 .

[0059] Depend on Figure 4 It can be seen that strain SK0 has characteristics such as nitrogen fixation, phosphorus solubilization, IAA production, siderophore production, and alkali production.

[0060] 2. Sugarcane pot experiment 2.1 Sugarcane Cultivation Conditions Before planting, apply 0.386 g / kg of urea, 0.89 g / kg of superphosphate (18%), and 0.29 g / kg of potassium chloride as base fertilizer, mix thoroughly, and hydrate for one week before planting. Select healthy ROC22 sugarcane stalks, cut them into 4 cm single-bud segments, soak them overnight in saturated lime water, and then germinate them in the substrate for 10 days. Select seedlings with uniform growth for transplanting. Use root-limiting pots for cultivation, with a pot height of 30 cm and a bottom diameter of 30 cm. Fill each pot with 15 kg of soil and plant 2 sugarcane seedlings. Monitor and replenish water daily at 18:00 to maintain soil moisture content between 70-80% of field capacity, and provide natural sunlight.

[0061] The experiment was set up with two treatments: CK: Control group, with no additives. SK0: Add strain SK0 bacterial suspension at a concentration of 1% of soil mass (v / m, bacterial suspension OD). 600 (Value 1.0). Each treatment was replicated in triplicate. Soil and plant samples were collected 90 days after planting for various parameters.

[0062] 2.2 Determination of Soil Physicochemical Properties Soil pH was determined using a pH meter (PHS-3C, Mettler Toledo, Shanghai), with a soil-to-water ratio of 2.5:1. Soil organic matter was determined using the potassium dichromate (K2Cr2O7) external heating method. Available phosphorus and potassium in the soil were extracted using 0.05 mol / L HCl–0.025 mol / L (1 / 2 H2SO4) and 1 mol / L CH3COONH4, respectively, and measured using a UV spectrophotometer (UV2501PC, SHIMADZU, Japan) and a flame photometer (ZA3300, HITACHI, Japan). Various forms of aluminum in the soil were determined using a modified continuous extraction and fractionation method. The extract was analyzed using an inductively coupled plasma optical emission spectrometer (ICP-OES) (ICP-5000, FPI, Beijing). The experimental procedures are as follows: (1) Exchangeable Al (AlEx) Weigh 1.0 g of air-dried and sieved soil sample, add 0.1 mol / L KCl solution at a soil-to-liquid ratio of 1:10 (g:mL), shake at room temperature for 30 min, then centrifuge for 5 min (3500 r / min, the same below). Filter the supernatant into a white plastic bottle as the extraction solution. Repeat the extraction twice and combine the extracts. Wash the residue with deionized water, centrifuge, and discard the supernatant.

[0063] (2) Weakly organically bound Al (AlOrw) Add 0.5 mol / L CuCl2 solution to the residue from the previous step at a soil-to-liquid ratio of 1:10 (g:mL), shake at room temperature for 2 hours, centrifuge, and filter the supernatant as the extract. Repeat the extraction twice and combine the extracts. Wash the residue with deionized water, centrifuge, and discard the supernatant.

[0064] (3) Organically bound Al (AlOr) Add 0.1 mol / L Na₄P₂O₇ (pH 10.0) solution to the above residue at a soil-to-liquid ratio of 1:40 (g:mL). Shake at room temperature for 2 hours, centrifuge, and filter the supernatant as the extract. Repeat the extraction twice and combine the extracts. Wash the residue with 1 mol / L Na₂SO₄, centrifuge, and discard the supernatant.

[0065] (4) Amorphous aluminum (AlAmo) Add 0.2 mol / L ammonium oxalate solution [(NH4)2C2O4, pH 3.0] to the above residue at a soil-to-liquid ratio of 1:40 (g:mL). Shake for 4 hours in the dark, then centrifuge and filter the extract. Wash the residue with deionized water, centrifuge and discard the supernatant.

[0066] (5) Iron oxide-bound Al (AlOxi) Add 0.3 mol / L Na3C6H5O7 to the above residue at a soil-to-liquid ratio of 1:40 (g:mL), then add 1 mol / L NaHCO3 at a soil-to-liquid ratio of 1:5, and add an appropriate amount of solid Na2S2O4. Stir the mixture in an 80℃ water bath for 15 min. After the reaction is complete, centrifuge and filter the extract. Wash the residue with 1 mol / L NaCl, centrifuge again, and discard the supernatant.

[0067] (6) Amorphous aluminosilicate and gibbsite Al (Al_Aag) The residue was placed in a nickel crucible, 0.1 mol / L NaOH solution was added, and the mixture was heated to boiling for 2.5 min. After cooling, the mixture was filtered, and the filtrate was used for aluminum content determination.

[0068] (7) Residual Al (AlRes) The residual soil sample after continuous extraction was dried in an oven, ground and pulverized, and 0.20 g was weighed and digested with HNO3-HF-HClO4 until clear. The volume was adjusted to 25 mL and filtered through a 0.45 μm filter membrane before analysis.

[0069] See results Figure 6 and Figure 7 .

[0070] Depend on Figure 6 and Figure 7 It is known that the microbial agent SK0 of the present invention can reduce the content of active aluminum in the soil, increase the content of soil nutrients, and is beneficial to the improvement of acidic soil.

[0071] 2.3 Determination of Aluminum Content in Sugarcane The Al content in sugarcane was determined by nitric acid-perchloric acid digestion. 0.2000 g of the pre-treated plant sample was accurately weighed into a glass digestion tube, and 5 mL of mixed acid (HNO3:HClO4 = 4:1, V / V) was added. A small bent-neck funnel was capped at the tube opening, and pre-digestion was performed at room temperature for 1 h. The digestion tube was then placed on a graphite digester and heated according to the following procedure: 80℃ for 15 min, 120℃ for 20 min, and finally heated to 180℃ until the solution in the tube became clear and the volume decreased to the size of a soybean. After cooling, the digest was transferred to a 50 mL volumetric flask and diluted to the mark with deionized water. A blank control was prepared simultaneously. The aluminum content of the plant was determined using ICP-OES, and the results are shown below. Figure 8 .

[0072] Depend on Figure 8 It is known that the strain SK0 of this invention can effectively reduce the absorption and accumulation of Al by sugarcane, thereby alleviating the Al toxicity of sugarcane and promoting sugarcane growth.

[0073] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An acid-resistant aluminum-tolerant strain SK0, characterized in that, The taxonomic name of the aluminum-resistant strain SK0 is *Bacillus paramicularis* (…). Bacillus paranthracis SK0 was deposited at the Guangdong Provincial Center for Microbial Culture Collection on April 28, 2026, with accession number GDMCC 68181.

2. A microbial agent, characterized in that, The bacterial agent includes the aluminum-resistant strain SK0 as described in claim 1.

3. The microbial agent according to claim 2, characterized in that, The aluminum-resistant strain SK0 in the bacterial agent has a bacterial count of 10. 9 -10 10 CFU / mL.

4. The application of the aluminum-resistant strain SK0 according to claim 1 or the bacterial agent according to any one of claims 2-3 in the remediation of aluminum toxicity and the promotion of crop growth.

5. The application of the aluminum-resistant strain SK0 according to claim 1 or the bacterial agent according to any one of claims 2-3 in reducing the absorption and accumulation of aluminum by plants and alleviating aluminum toxicity in sugarcane.

6. The application of the aluminum-resistant strain SK0 according to claim 1 or the bacterial agent according to any one of claims 2-3 in reducing the exchangeable aluminum content in soil, reducing the organically bound aluminum content in soil, increasing soil pH and organic matter content, or increasing sugarcane yield.

7. The use of the aluminum-resistant strain SK0 of claim 1 or the bacterial agent of any one of claims 2-3 in the preparation of a product for removing aluminum from soil.

8. The application of the aluminum-resistant strain SK0 of claim 1 or the bacterial agent of any one of claims 2-3 in converting trivalent aluminum into organically bound aluminum.

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