Salt stress resistant and phosphate solubilizing penicillium oxalicum and product and application thereof

Abstract

The invention belongs to the technical field of microorganisms, and particularly relates to salt-stress-resistant and phosphate-solubilizing penicillium oxalicum as well as a product and application thereof. The invention provides a penicillium oxalicum, the collection date of the penicillium oxalicum is October 26, 2022, the penicillium oxalicum is collected in the China General Microbiological Culture Collection Center, and the collection number is CGMCC No.40346. The penicillium oxalicum has the advantages that the preservation number is CGMCC No.40346; the Penicillium oxalicum provided by the invention has the functions of salt stress resistance and phosphate solubilization, can improve the utilization rate of insoluble phosphate in the saline-alkali soil and remarkably improve the content of soluble phosphorus in the saline-alkali soil, has wide application prospects in saline-alkali soil remediation and soil fertility improvement, and has profound significance in agricultural production activities.

Description

Technical Field

[0001] The present invention belongs to the technical field of microbiology, and particularly relates to a Penicillium oxalicum that is salt stress-tolerant and phosphorus-solubilizing, and its products and applications. Background Art

[0002] Phosphorus is an essential necessity for life. It is an important component element of DNA and is also the P in ATP (adenosine triphosphate, a molecule that provides energy for cells). Plants need phosphorus to grow, so phosphate fertilizers need to be applied to all crops. Soluble phosphorus plays an important role in the growth process of plants. However, due to the stress of high-concentration salts, the soil in the saline-alkali land of the Yellow River Delta is barren, the content of soluble phosphorus is low, and the activity of soil microorganisms is low.

[0003] Phosphorus solubilization, also known as phosphorus release, refers to the process in which under the action of microorganisms, organic phosphorus compounds in the soil are converted into phosphates (POT) or insoluble phosphorus in the soil is converted into soluble phosphorus. It can increase the content of available phosphorus in the soil and is beneficial to plant growth. By screening microorganisms with phosphorus-solubilizing effects, the conversion of organic phosphorus compounds in the soil into phosphates or the conversion of insoluble phosphorus in the soil into soluble phosphorus can be promoted.

[0004] Chinese Patent Application No. 202210830139.3 discloses a phosphorus-solubilizing bacterium, the strain name: Pantoea sp. ( Pantoea sp. ) GRINML12, the depositary institution is: China Center for Type Culture Collection, address: Wuhan University, Wuhan, China, the deposit date is: November 20, 2019, and the deposit number is: CCTCC NO: M2019960. This bacterium is used to dissolve insoluble inorganic phosphorus sources into free phosphate, and U(VI) in the uranium pollution system reacts with free phosphate to form stable uranyl phosphate minerals through coprecipitation reactions.

[0005] Chinese Patent Application No. 202310835034.1 discloses a Klebsiella variicola M15C3 and its applications. The Klebsiella variicola M15C3 has the ability to solubilize phosphorus, can increase the content of available phosphorus in the soil, and improve the soil environment. Klebsiella variicola M15C3 has positive effects in accelerating the conversion of straw returned to the field, improving soil fertility, and promoting crop growth.

[0006] Penicillium oxalicum ( Penicillium oxalicum ) is a fungus widely existing in nature and belongs to the genus Penicillium ( Penicillium). It has important application values in the fields of agriculture, industry and environment, especially in aspects such as phosphorus solubilization, biological control and biodegradation. The phosphorus solubilization mechanism of Penicillium oxalicum mainly depends on the organic acids it produces. These organic acids can reduce the pH value of the soil, thereby increasing the solubility of insoluble inorganic phosphorus. At the same time, organic acids can also combine with metal ions in the soil to form soluble metal-organic acid complexes, further promoting the release of phosphorus. In addition, Penicillium oxalicum also secretes phosphatases (such as acid phosphatase) to decompose organic phosphorus compounds and release inorganic phosphorus that can be absorbed by plants. Specifically, Penicillium oxalicum produces various organic acids during growth, such as oxalic acid, citric acid, malic acid, etc. These organic acids convert insoluble phosphorus compounds in the soil into soluble phosphorus through dissolution. In addition, Penicillium oxalicum can also indirectly promote the absorption and utilization of phosphorus by plants by regulating the soil environment, such as improving soil aeration and water permeability, which is beneficial to the growth and development of plant roots.

[0007] As a multifunctional fungus, Penicillium oxalicum has important application values in phosphorus solubilization, biodegradation and industrial production. Therefore, it is urgent to develop more Penicillium oxalicum with high efficiency and environmental protection for phosphorus solubilization.

[0008] Saline-alkali land has a high salt content and poor soil fertility, resulting in difficulties for plants and microorganisms to survive. Even if salt-tolerant plants can grow, they lack nutrients and grow relatively slowly. The cost of artificially adding P fertilizers is high, and they are easily lost and have low utilization rates. Using microorganisms that can tolerate salt stress and solubilize phosphorus to improve saline-alkali soil is a difficult problem that needs to be solved currently. Summary of the Invention

[0009] In order to overcome the defects of the prior art, the present invention screened phosphorus-solubilizing and growth-promoting bacteria from the rhizosphere soil of pioneer plants for ecological restoration of saline-alkali land, and finally obtained a Penicillium oxalicum ( Penicillium oxalicum ).

[0010] The technical solution for the present invention to achieve the above technical objectives is as follows: On the one hand, the present invention provides a Penicillium oxalicum, the preservation date of the Penicillium oxalicum is October 26, 2022, and it is preserved in the General Microbiological Center of the China Committee for Culture Collection of Microorganisms, with the preservation number CGMCC No. 40346.

[0011] On the other hand, the present invention provides a culture, and the culture is obtained by inoculating the aforementioned Penicillium oxalicum in a culture medium.

[0012] The inoculation amount of the inoculation described can be 0.1% - 20%, and in some cases, it can also be a higher or lower inoculation amount. Specifically, the inoculation amount can be 1% - 20%, 2% - 20%, 1% - 15%, 1% - 10%, 1% - 5%, 1% - 8%, 5% - 15%, 5% - 10%, 5% - 8%, 8% - 10%, 8% - 15%, 5% - 12%, 2% - 7%.

[0013] Specifically, the culture medium can be a solid culture medium, a semi-solid culture medium or a liquid culture medium. More specifically, it can be any suitable culture medium type already disclosed in the prior art, or a culture medium obtained by further improving the culture medium type disclosed in the prior art to improve the performance of the strain, or a culture medium not disclosed in the prior art but capable of being used for culturing the aforementioned Penicillium oxalicum.

[0014] The culture conditions provided by the present invention for Penicillium oxalicum include temperature and oxygen content, and in some cases, may also include light, carbon dioxide content, pH, humidity, stirring conditions, ventilation conditions, oscillation conditions, culture medium replacement conditions, culture days, resistance conditions, etc.

[0015] Preferably, the temperature in the culture conditions can be 20 - 30 °C, specifically it can be 25 - 30 °C, 26 - 30 °C, 2 - 30 °C, 28 - 30 °C, 29 - 30 °C, 21 - 30 °C, 22 - 30 °C, 23 - 30 °C, 24 - 30 °C, 21 - 29 °C, 21 - 28 °C, 21 - 27 °C, 21 - 26 °C, 21 - 25 °C, 29.5 - 30 °C, 25.5 - 29.5 °C, 27 - 29.5 °C or 26 - 27.5 °C. Further preferably, it is 29.5 - 30 °C, and even more preferably 30 °C.

[0016] Preferably, the culture is anaerobic culture, and the oxygen content in the culture conditions can be 0% - 8%, specifically it can be 0% - 7%, 0% - 6%, 0% - 5%, 0% - 4%, 0% - 3%, 0% - 2%, 0% - 1%, 0% - 5.5%, 0% - 3.5%, 0% - 2.5%, 0% - 0.5%, 1% - 8%, 1% - 5%, 1% - 2% or 0.5% - 2%.

[0017] In some examples, the culture includes isolates and / or pure cultures.

[0018] In some examples, the culture is selected from at least one of culture broth, culture broth extract, whole bacteria, whole bacteria extract, fermentation broth, and fermentation broth extract.

[0019] In another aspect, the present invention provides a microbial inoculant, which includes the aforementioned Penicillium oxalicum or culture.

[0020] In some examples, the microbial inoculant further includes adjuvants, which are selected from at least one of solvents, diluents, disintegrants, precipitation inhibitors, surfactants, glidants, binders, lubricants, dispersants, suspending agents, isotonics, thickeners, emulsifiers, preservatives, stabilizers, humectants, emulsification accelerators, buffers, absorbents, colorants, flavoring agents, sweeteners, ion exchangers, mold release agents, coating agents, flavor correctors, and antioxidants.

[0021] In some examples, the dosage form of the microbial inoculant is selected from at least one of powders, tablets, granules, capsules, solutions, emulsions, suspensions, injections, sprays, powder aerosols, aerosols, suppositories, drops, and dripping pills.

[0022] On the other hand, the present invention provides the use of the aforementioned Penicillium oxalicum or culture or microbial inoculant in the preparation of phosphorus-dissolving products.

[0023] On the other hand, the present invention provides a phosphorus-dissolving product, which includes the aforementioned Penicillium oxalicum or culture or microbial inoculant.

[0024] In some examples, the phosphorus-dissolving product further includes at least one of nutrient agents, trace elements, or surfactants.

[0025] In some examples, the phosphorus-dissolving product includes biological fertilizers, phosphorus-dissolving agents, soil conditioners, soil improvers, or soil remediation agents.

[0026] On the other hand, the present invention provides the use of the aforementioned Penicillium oxalicum or culture or microbial inoculant or phosphorus-dissolving product in soil improvement.

[0027] Specifically, the soil improvement includes soil conditioning or remediation.

[0028] In some examples, the soil is a soil lacking soluble phosphorus.

[0029] On the other hand, the present invention provides the use of the aforementioned Penicillium oxalicum or culture or microbial inoculant or phosphorus-dissolving product in improving soil fertility.

[0030] In some embodiments, the soil is a soil lacking soluble phosphorus.

[0031] The Penicillium oxalicum PF1 provided by the present invention has salt stress tolerance and phosphorus-dissolving function, can improve the utilization rate of insoluble phosphates in saline-alkali soil, significantly increase the content of soluble phosphorus in saline-alkali soil, has broad application prospects in saline-alkali soil remediation and improving soil fertility, and has far-reaching significance in agricultural production activities.

[0032] Preservation information: Biological material: PF1; Classification and Naming: Penicillium oxalicum ( Penicillium oxalicum ); Deposit Number: CGMCC No. 40346; Deposit Date: October 26, 2022; Depositary Institution: China General Microbiological Culture Collection Center; Deposit Address: No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing. Brief Description of the Drawings

[0033] Figure 1 and Figure 2 show the growth of Penicillium oxalicum PF1 on the culture plate.

[0034] Figure 3 show the phosphorus solubilizing zones of Penicillium oxalicum PF1 (calcium phosphate, magnesium phosphate, iron phosphate from left to right in sequence).

[0035] Figure 4 show the phosphorus standard concentration curve.

[0036] Figure 5 show the pH value and phosphorus content of the culture solution (calcium phosphate).

[0037] Figure 6 show the pH value and phosphorus content of the culture solution (magnesium phosphate).

[0038] Figure 7 show the pH value and phosphorus content of the culture solution (iron phosphate).

[0039] Figure 8 show the growth of Penicillium oxalicum PF1 in the salt tolerance test (salt contents 0%, 2%, 4% from left to right in the upper row, and salt contents 6%, 8%, 10%, 12% from left to right in the lower row).

[0040] Figure 9 show the growth of Penicillium oxalicum PF1 in the salt tolerance test (salt contents 14%, 15%, 16% from left to right in the upper row, and salt contents 17%, 18% from left to right in the lower row).

[0041] Figure 10 show the growth of Penicillium oxalicum PF1 in the salt tolerance test (salt content 16% in the upper row, and salt contents 17%, 18% from left to right in the lower row). Detailed Embodiments

[0042] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly used in the field to which this invention belongs. For the purpose of interpreting this specification, the following definitions will be applied, and where appropriate, terms used in the singular form will also include the plural form, and vice versa.

[0043] Unless otherwise clearly specified in the context, the expressions "a" and "an" as used herein include plural referents. For example, reference to "a cell" includes a plurality of such cells and equivalents known to those skilled in the art, and so on.

[0044] Reagents and materials related to the present invention: (a)Test soil samples: The test soil samples were collected from the field experimental station of the Yellow River Delta Comprehensive Experiment Center, Chinese Academy of Forestry Sciences (118°54’4’’E, 37°38’36’’N). The selected plant was the rhizosphere soil of Tamarix chinensis. When collecting, with the main stem of the plant on the ground as the center and a radius of 20 cm, the surface salt crust and the upper covering soil were removed, the underground part of the plant was dug out as a whole, the soil at a distance of 5 - 20 cm from the ground was taken, stored in a sterile sample bag, and transported back to the laboratory for testing at low temperature with an ice pack.

[0045] (b)Culture media: LB culture medium: 10 g of peptone, 5 g of yeast extract, 10 g of NaCl, 1000 mL of distilled water, pH 7.0 - 7.2 (15 g of agar was added to the solid culture medium on this basis).

[0046] Inorganic phosphorus culture medium: 10 g of glucose, 0.5 g of yeast extract, 0.5 g of (NH4)2SO4, 0.3 g of NaCl, 0.3 g of KCl, 0.3 g of MgSO4, 0.03 g of MnSO4, 0.03 g of FeSO4, 5 g of phosphorus source, 1000 mL of distilled water, pH 7.0 - 7.5 (15 g of agar was added to the solid culture medium on this basis).

[0047] (c)Molybdenum-antimony storage solution: Measure 153 mL of concentrated sulfuric acid, slowly add it to 400 mL of distilled water, stir continuously, and cool. Separately weigh 10 g of finely ground ammonium molybdate and dissolve it in 300 mL of deionized water at about 60°C, and cool. Then slowly pour the sulfuric acid solution into the ammonium molybdate solution. Then add 100 mL of 0.5% potassium antimonyl tartrate solution, make up the volume to 1 L with deionized water after cooling, shake well, and store in a brown reagent bottle.

[0048] (d)Molybdenum-antimony-ascorbic acid color reagent: Add 1.5 g of ascorbic acid to 100 mL of the storage solution and prepare it for immediate use.

[0049] (e)5 mg / L phosphorus standard stock solution: Accurately weigh 0.4394 g of potassium dihydrogen phosphate (GB1274, guaranteed reagent grade) dried at 105°C for 2 h, dissolve it in water, add 5 mL of concentrated sulfuric acid, and make up the volume to 1 L with water. This solution contains 100 mg / L of phosphorus and can be stored in the refrigerator for long-term use.

[0050] Experimental method of the present invention: (f)Molybdenum-antimony anti-colorimetric method: Prepare a standard solution of 0 - 1.2 μg / mL with potassium dihydrogen phosphate dried to constant weight. Add 1 mL of ascorbic acid solution and 2 mL of molybdate solution to a 25 mL sample system and mix well. Measure the absorbance at a wavelength of 700 nm. Dilute the fermentation filtrate with deionized water to an appropriate multiple for measurement, and quantitatively determine the phosphorus-solubilizing ability of phosphorus-solubilizing bacteria by the molybdenum-antimony anti-method.

[0051] (1)Drawing of the standard curve: Respectively pipette 0 mL, 2 mL, 4 mL, 6 mL, 8 mL, 10 mL of 5 mL phosphorus standard solution into 50 mL volumetric flasks. At the same time, add a blank solution with the same volume as the sample solution used for color development determination. Add 2 drops of dinitrophenol indicator, and adjust to just slightly yellow with 100 g / L sodium carbonate solution or 50 mL / L sulfuric acid solution. Accurately add 5 mL of molybdenum-antimony anti-color reagent, shake well, and place at room temperature above 15 °C for 30 min. Measure the absorbance at a wavelength of 700 nm, with the absorbance as the ordinate and the phosphorus concentration (mg / L) as the abscissa, and draw the standard curve.

[0052] (2)Determination of soluble phosphorus: Pipette an appropriate amount of the sample to be measured (fermentation supernatant) into a 50 mL volumetric flask, dilute with water to about 3 / 5 of the total volume, add 1 - 2 drops of dinitrophenol indicator, and adjust to just slightly yellow with 100 g / L sodium carbonate solution. Accurately add 5 mL of molybdenum-antimony anti-color reagent, shake well, make up the volume with water, and place at room temperature for 30 min. Measure the absorbance value of the colored sample at 700 nm and calculate the phosphorus content.

[0053] To make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the following further details the present invention in combination with embodiments. For those not specified in the embodiments, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. All reagents or instruments not specified by the manufacturer can be obtained as conventional products through commercial purchase. To better illustrate the present invention, numerous specific details are given in the following specific embodiments. The specific embodiments described herein are only used to explain the present invention and do not constitute any limitation to the present invention. In addition, in the following description, the description of well-known structures and technologies is omitted to avoid unnecessarily confusing the concept of the present invention. Such structures and technologies are also described in many publications, such as "Molecular Cloning: A Laboratory Manual (Fourth Edition)" (Cold Spring Harbor Laboratory Press), Ausubel, F.M et al., Current Protocols in Molecular Biology , Greene Publishing Assoc. and Wiley-Interscience publications.

[0054] Example 1 Isolation and screening of Penicillium oxalicum Take 5 g of soil sample and add 45 mL of sterile water. Shake it in a shaker at 30 °C and 120 rpm for 30 min to prepare a suspension. After standing for 15 min, perform gradient dilution (10 -1 、10 -2 、10 -3 、10 -4 、10 -5 、10 -6 ). Pipette 0.1 mL of the suspension from each gradient and spread it on the inorganic phosphorus medium plate. There are 2 parallels for each gradient. Incubate at 28 °C for 5 - 7 d, and pick the single colonies with obvious clear zones. Select the strains with higher phosphorus-solubilizing ability for purification. After purifying 3 times, pick single colonies and inoculate them onto the LB slant for 2 - 3 d for storage for later use.

[0055] Result screening yielded a strain PF1. The sequencing result showed it was Penicillium oxalicum ( Penicillium oxalicum ). The growth of Penicillium oxalicum PF1 on the culture plate is shown in Figure 1 - Figure 2 .

[0056] Example 2 Detection of phosphorus-solubilizing ability of Penicillium oxalicum PF1 Pick single colonies of the Penicillium oxalicum PF1 strain obtained by isolation and purification and inoculate them into the LB liquid medium for overnight culture (OD 600 controlled between 0.6 - 0.7) to obtain a bacterial solution.

[0057] 2.1 Phosphorus-solubilizing circle (qualitative test) Set up inorganic phosphorus solid media with calcium phosphate, iron phosphate, and magnesium phosphate as phosphorus sources, and the phosphorus concentration is 5 g / L for all. Pipette 20 μL of the bacterial solution and spot-inoculate it in the center of the medium. Incubate at 28 °C for 10 d, and set up three parallels for each phosphorus source. Observe the growth of the strain and measure the ratio of the diameter D of the clear zone to the diameter d of the colony to roughly reflect the phosphorus-solubilizing ability of the strain. The results are shown in Table 1 and Figure 3 .

[0058] Table 1 D / d values of Penicillium oxalicum PF1 under different phosphorus sources

[0059] According to the results of the phosphorus-solubilizing circle test, the phosphorus-solubilizing ability of the strain for different phosphorus sources is calcium phosphate > magnesium phosphate > iron phosphate.

[0060] 2.2 Liquid culture (quantitative test) The prepared bacterial liquid was inoculated into the inorganic phosphorus liquid medium at an inoculation amount of 1% (v / v). The phosphorus sources were also set up with three experimental groups of calcium phosphate, magnesium phosphate, and iron phosphate, and the phosphorus concentration was 5 g / L for each. Three parallels were set up for each experimental group. The CK group was the treatment without adding Penicillium oxalicum. It was cultured with shaking at 28 °C and 180 rpm for 7 days. The supernatant was sampled daily under sterile conditions to measure the pH value and the soluble phosphorus content (molybdenum antimony anti-colorimetric method). The determination of the phosphorus standard concentration curve is shown in Table 2 and Figure 4 as follows.

[0061] Table 2 Determination of the phosphorus standard concentration curve

[0062] Take 15 mL of the supernatant diluted to an appropriate concentration and place it in a 50 mL volumetric flask. Add 2 - 3 drops of the indicator, and adjust the solution to just turn slightly yellow. Then add 5 mL of the molybdenum antimony anti-color reagent, shake well and make up the volume to 50 mL. Measure its absorbance at a wavelength of 700 nm. The results are shown in Tables 3, 4, and 5.

[0063] Among them, the data in the "()" in Tables 3, 4, and 5 are the data under the corresponding conditions of the CK group.

[0064] Table 3 pH value and phosphorus content of the culture solution (calcium phosphate)

[0065] The results show that (Table 3, Figure 5 ), within the 7-day culture period, the pH value of the culture solution was stable between 2 - 3, and the highest phosphorus content could reach 980.09 mg / L, which was 1507.23% higher than the highest phosphorus content value of the CK group.

[0066] Table 4 pH value and phosphorus content of the culture solution (magnesium phosphate)

[0067] The results show that (Table 4, Figure 6 ), within the 7-day culture period, the pH value of the culture solution was stable between 7 - 8, and the highest phosphorus content could reach 267.20 mg / L, which was 927.30% higher than the highest phosphorus content value of the CK group.

[0068] Table 5 pH value and phosphorus content of the culture solution (iron phosphate)

[0069] The results show that (Table 5, Figure 7 ), within the 7-day culture period, the pH value of the culture solution was stable between 2 - 3, and the highest phosphorus content could reach 17.83 mg / L, which was 60.92% higher than the highest phosphorus content value of the CK group.

[0070] According to the results of liquid culture experiments, it can be seen that there are significant differences in the phosphate-solubilizing ability of strains among different phosphate sources. Moreover, during the phosphate-solubilizing process, the pH value of the culture medium in the experimental group decreased significantly compared with the CK group. The reason may be that organic acids are released during the phosphate-solubilizing process of the strains, and it cannot be excluded that too low pH will have a negative impact on the growth and function of the strains.

[0071] Example 3 Salt Tolerance Limit Test Inoculate the strain into LB liquid medium and shake-culture it at 28 °C and 180 rpm. Control the OD600 value of the bacterial liquid between 0.6 - 0.7 and stop shaking. Set the salt concentration gradients of PDA medium to 0%, 2%, 4%, 6%, 8%, 10%, 12%, 14%, 15%, 16%, 17%, 18% (w / v). Pipette 20 μL of the bacterial liquid and spot-inoculate it in the center of the salt-containing medium. Set three parallels for each gradient, and quantitatively observe the growth of the strain daily. After culturing for 10 d, measure the colony diameter.

[0072] Table 6 Colony Diameters of Penicillium oxalicum PF1 at Different Salt Contents

[0073] The results show (Table 6, Figure 8 , Figure 9 , Figure 10 ) that when inoculated on the medium with a salt content of 0% - 12%, the strain spreads and grows vigorously; starting from a salt content of 14% and 15%, the growth of the strain begins to be inhibited, but it can still grow normally; at a salt content of 16% - 17%, the growth inhibition is significant, but white colonies can still be seen on the medium, and the strain can still survive and colonize; when the salt content is 18%, no colonies are formed and the strain stops growing.

[0074] From the above related experiments, it can be seen that the test strain Penicillium oxalicum PF1 has excellent salt tolerance.

[0075] It should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than a limitation on the protection scope of the present invention. Any simple modification or equivalent replacement of the technical solution of the present invention by those of ordinary skill in the art does not depart from the essence and scope of the technical solution of the present invention.

Claims

1. A Penicillium oxalicum ( Penicillium oxalicum ), characterized in that The preservation date of the Penicillium oxalicum is October 26, 2022, and it is preserved in the General Microbiology Center of the China Committee for Culture Collection of Microorganisms with the preservation number of CGMCC No. 40346.

2. A culture, characterized in that, The culture is obtained by inoculating the Penicillium oxalicum described in claim 1 into a culture medium.

3. A microbial inoculant, characterized in that, The microbial inoculum includes the Penicillium oxalicum described in claim 1 or the culture described in claim 2.

4. The microbial inoculum according to claim 3, wherein The microbial inoculum further includes excipients, and the excipients are selected from at least one of diluents, disintegrants, precipitation inhibitors, surfactants, glidants, binders, lubricants, dispersants, suspending agents, isotonizing agents, thickeners, emulsifiers, preservatives, stabilizers, emulsification accelerators, buffers, absorbents, colorants, flavoring agents, sweeteners, ion exchangers, demolding agents, coating agents, taste-correcting agents, and antioxidants.

5. The microbial inoculum according to claim 4, characterized in that, The dosage form of the microbial inoculum is selected from at least one of powders, tablets, granules, capsules, solutions, emulsions, suspensions, injections, aerosols, suppositories, and drops.

6. Use of the Penicillium oxalicum described in claim 1, the culture described in claim 2, or the microbial inoculum described in any one of claims 3-5 in the preparation of a phosphorus-dissolving product.

7. A phosphorus-solubilizing product, characterized in that, The phosphorus-dissolving product includes the Penicillium oxalicum described in claim 1, the culture described in claim 2, or the microbial inoculum described in any one of claims 3-5.

8. The phosphorus-dissolving product according to claim 7, characterized in that, The phosphorus-dissolving product further includes at least one of nutrient agents, trace elements, or surfactants.

9. The phosphorus-solubilizing product according to claim 7 or 8, characterized in that, The phosphorus-dissolving product includes biological fertilizers, soil conditioners, soil improvers, or soil remediation agents.

10. Use of Penicillium oxalicum according to claim 1, the culture according to claim 2, the microbial inoculum according to any one of claims 3-5, or the phosphorus-solubilizing product according to any one of claims 7-9 in soil improvement, characterized in that, The soil improvement includes soil conditioning or remediation.

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