Microbial preparation for passivating heavy metal cadmium in soil and improving yield and quality of crops and application of microbial preparation

Abstract

The invention discloses a microbial preparation for passivating soil heavy metal cadmium and improving crop yield and quality and application of the microbial preparation, and belongs to the technical field of microbial preparations. The rhizopus arrhizus WG01 is preserved in the China General Microbiological Culture Collection Center (CGMCC) on September 9, 2024, the preservation address is No.3, Yard 1, Beichen West Road, Chaoyang District, Beijing, and the preservation number is CGMCC No.41501. The microbial solid preparation is prepared by fermenting two strains of rhizopus arrhizus WG01 and burkholderia by taking wheat bran and charcoal as carrier auxiliary materials, and then compounding with calcium superphosphate in proportion. When the microbial preparation is applied to soil, heavy metal cadmium in the soil can be passivated through the effects of adsorption, precipitation and the like, meanwhile, the content of organic matter and rapidly available phosphorus in the soil is increased through the addition of wheat bran, biochar, inorganic phosphorus and the like and the phosphorus dissolving effect of microorganisms, and yield increase and quality improvement of crops are achieved. The microbial solid preparation is convenient to use, green and pollution-free, and has the advantages of passivating soil heavy metals, improving soil fertility, increasing crop yield and the like.

Description

Technical Field

[0001] The invention relates to the technical field of microbial preparations, and in particular to a microbial preparation for passivating soil heavy metal cadmium and improving crop yield and quality, and application thereof. Background Art

[0002] The rate of excessive heavy metal pollution in soil in my country is as high as 16%. Not only does it have a wide radiation range, but it is also long-term, persistent, hidden, and non-biodegradable, making it extremely difficult to repair and manage, posing a great threat to human life and health. At the same time, due to the excessive pursuit of high crop yields in recent years, excessive and unscientific fertilization has become more and more serious, resulting in a serious imbalance in nutrient ratios, a decrease in crop nutrient absorption efficiency, and serious waste of resources, especially phosphorus, which has extremely low effectiveness in the soil. The research and development of soil conditioners that can repair soil heavy metal pollution and regulate soil nutrient balance and effectiveness is of great significance to improving crop quality and achieving high crop yields.

[0003] At present, there are three methods for soil heavy metal pollution control: physical remediation, chemical remediation and biological remediation. Physical remediation is difficult to implement due to its high cost, while chemical remediation mostly repairs heavy metals by adding chemical materials to the soil, which has a high risk of "secondary pollution". Microbial remediation technology uses indigenous or artificially domesticated microorganisms with specific functions to reduce the activity of heavy metals in the soil through their own metabolism. It has a low application cost and is relatively simple to operate, and is highly valued and respected.

[0004] However, the disadvantage of microbial remediation of heavy metal pollution in soil is that it is easily affected by external factors, which leads to a longer treatment period and a decrease in treatment efficiency. The patent "Heavy Metal Polluted Soil Microbial Remediation Agent and Its Application" (Application No. 201410682558.2) discloses a heavy metal polluted soil conditioner with Bacillus subtilis and Candida tropicalis as active ingredients, which can adsorb and passivate heavy metals; however, Candida tropicalis is an anaerobic bacterium, while Bacillus subtilis is an aerobic bacterium. The living environments of the two strains are mutually exclusive, which seriously affects their efficiency in repairing heavy metal pollution. The patent "A soil remediation microbial agent with heavy metal resistance" (application number 202310663745.5) discloses a soil remediation microbial agent with heavy metal resistance that is rich in Acinetobacter baumannii, Pseudomonas and Pseudomonas mendocinae; the agent has good heavy metal tolerance, and can passivate and stabilize a variety of free heavy metal ions, providing an effective method for the treatment of heavy metal pollution; however, the agent is applied by soil spraying, and is applied once a week, which has high manpower and economic costs; in addition, the strain dosage applied by foliar spray is too small, and it is applied without suitable organic carrier excipients, and the colonization rate in the soil is difficult to guarantee, thereby affecting the passivation effect of soil heavy metals. In addition, the above invention is limited to the remediation of soil heavy metal pollution, and does not involve the effectiveness of soil nutrients and their effects on fertility.

[0005] Soil is a resource library of microbial strains with many species, active metabolism and diverse pathways. Exploring complex strains that can grow synergistically, adsorb and fix heavy metals well, activate soil nutrients, and make them into simple-to-use, green and pollution-free solid preparations is a hot topic in the field of soil heavy metal pollution remediation and soil fertility quality improvement technology research and development. Summary of the invention

[0006] The purpose of the present invention is to provide a microbial preparation for passivating soil heavy metal cadmium and improving crop yield and quality and its application, so as to solve the problems existing in the above-mentioned prior art.

[0007] To achieve the above object, the present invention provides the following solutions:

[0008] One of the technical solutions of the present invention is a strain of Rhizopus arrhizus WG01, which is deposited in the General Microbiology Center of China Microbiological Culture Collection Administration, with a deposit date of September 9, 2024, a deposit address of No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing, and a deposit number of CGMCC No.41501.

[0009] The second technical solution of the present invention is a microbial preparation, comprising Rhizopus arrhizus WG01 and Burkholderia;

[0010] The Burkholderia bacteria are from China Industrial Microbiological Culture Collection Center, with the number CICC10959;

[0011] The number ratio of the Rhizopus arrhizus WG01 and Burkholderia spp. is 1:1.

[0012] The third technical solution of the present invention is a method for preparing the microbial preparation, comprising the following steps: inoculating the seed solution of Rhizopus arrhizus WG01 into a fermentation matrix for fermentation and culturing, inoculating the seed solution of Burkholderia after the fermentation is completed, and culturing again to obtain a fermentation product;

[0013] The fermented product is mixed with superphosphate to obtain the microbial preparation.

[0014] A fourth technical solution of the present invention is the use of the Rhizopus arrhizus WG01 or the microbial preparation in the treatment of heavy metal cadmium.

[0015] A fifth technical solution of the present invention is the use of the Rhizopus arrhizus WG01 or the microbial preparation in promoting phosphorus dissolution.

[0016] Based on the above technical solution, the present invention has the following technical effects:

[0017] In the microbial agent provided by the present invention, both strains WG01 and Burkholderia are aerobic bacteria and can grow synergistically on a common culture medium, and the composite strain has a high cadmium adsorption and fixation ability, and can be used for the passivation of heavy metal cadmium in soil or the removal of cadmium in a water environment; the strains, auxiliary materials and superphosphate in the microbial preparation can all play a role in passivating the heavy metal cadmium in the soil, thereby inhibiting the absorption of cadmium by wheat roots and the enrichment of cadmium in grains; the superphosphate in the microbial preparation can directly supplement phosphorus, and the WG01 strain can also dissolve mineral phosphorus, thereby increasing the total phosphorus and available phosphorus content in the soil, promoting the phosphorus absorption by wheat roots and the phosphorus enrichment in grains; auxiliary materials such as wheat bran and biochar in the microbial preparation are added as organic materials or carbon and nitrogen sources, which can increase the organic matter and total nitrogen content in the soil, improve the soil fertility quality and increase the wheat grain yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 These are the morphological characteristics of the hyphae of Rhizopus arrhizus fungus WG01.

[0020] Figure 2The cadmium tolerance, cadmium fixation and cadmium removal capabilities of Rhizopus arrhizus WG01. Among them, A is the removal rate of heavy metal Cd, B is the dry weight of mycelium, and C is the amount of Cd removed per unit mass of mycelium.

[0021] Figure 3 The phosphorus solubilizing and cadmium fixing capabilities of Rhizopus arrhizus WG01, where A is the dry weight of mycelium, B is the removal rate of heavy metal Cd, and C is the phosphorus concentration of the solution.

[0022] Figure 4 The cadmium resistance and cadmium fixation ability of Burkholderia.

[0023] Figure 5 The colony characteristics of Rhizopus arrhizus WG01 co-cultured with Burkholderia (A) and its cadmium fixation ability (B).

[0024] Figure 6 This is a photo of the actual microbial preparation obtained.

[0025] Figure 7 The results of the field application experiment of microbial preparations. A is the wheat grain yield, B is the cadmium content of wheat grains, and C is the phosphorus content of wheat grains. DETAILED DESCRIPTION

[0026] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0027] It should be understood that the terms described in the present invention are only for describing special embodiments and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0028] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0029] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present application description and examples are exemplary only.

[0030] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0031] The technical solutions described in the present invention, unless otherwise specified, are all conventional solutions in the art, and the reagents or raw materials used, unless otherwise specified, are purchased from commercial channels or have been disclosed.

[0032] The embodiment of the present invention provides a strain of Rhizopus arrhizus WG01, which is deposited in the General Microbiological Center of China Microbiological Culture Collection Administration, with a deposit date of September 9, 2024, a deposit address of No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing, and a deposit number of CGMCC No. 41501.

[0033] The embodiment of the present invention also provides a microbial preparation, including Rhizopus arrhizus WG01 and Burkholderia;

[0034] The Burkholderia bacteria are from China Industrial Microbiological Culture Collection Center, with the number CICC10959;

[0035] The number ratio of the Rhizopus arrhizus WG01 and Burkholderia spp. is 1:1.

[0036] The embodiment of the present invention also provides a method for preparing the microbial preparation, comprising the following steps: inoculating a seed solution of Rhizopus arrhizus WG01 into a fermentation matrix for fermentation and culturing, inoculating the seed solution of Burkholderia after the fermentation is completed, and culturing again to obtain a fermentation product;

[0037] The fermented product is mixed with superphosphate to obtain the microbial preparation.

[0038] In some specific embodiments, the fermentation substrate includes wheat bran, wheat straw biochar and potato brown sugar water;

[0039] The preparation method of the fermentation matrix comprises: mixing wheat bran and wheat straw biochar in a mass ratio of (10-20):1, adding water to adjust the water content to 60%, then adding potato brown sugar water in a liquid-to-solid ratio of (400-500) mL:3 kg, and adjusting the water content of the fermentation matrix to 40%-60%.

[0040] In some specific embodiments, the wheat bran and wheat straw biochar are mixed and sterilized at 115° C. for 20 minutes. The grain size of the wheat bran and wheat straw biochar is 2 mm.

[0041] In some specific embodiments, the method for preparing the wheat straw biochar is anaerobically calcining the wheat straw at 550° C. for 8 h;

[0042] The preparation method of the potato brown sugar water is as follows: boiling potatoes with water until they are soft, filtering to obtain clarified potato juice, and adding brown sugar to the potato juice until the brown sugar is completely dissolved;

[0043] The mass ratio of potatoes to water is 1:5;

[0044] The volume mass ratio of the potato juice to brown sugar is 20 mL:1 g.

[0045] In some specific embodiments, the concentration of the Rhizopus arrhizus WG01 seed solution is 10 8 -10 12 cfu / mL, the inoculation volume is 400-500mL per 3kg fermentation substrate;

[0046] The fermentation culture conditions are as follows: fermentation at 28° C. for 5 to 7 days.

[0047] In some specific embodiments, the Rhizopus arrhizus WG01 seed solution is prepared using PDB culture medium, and the culture time is 4-8 hours.

[0048] In some specific embodiments, the concentration of the Burkholderia seed solution is 10 8 -10 12 cfu / mL, the inoculation volume is 400-500mL per 3kg fermentation substrate;

[0049] The condition for the secondary culture is fermentation at 28° C. for 4 hours.

[0050] In some specific embodiments, the Burkholderia seed solution is prepared using LB liquid culture medium, and the culture time is 2-4 hours.

[0051] In some specific embodiments, the dry weight ratio of the fermentate to superphosphate is 1:10.

[0052] In some specific embodiments, the superphosphate is in granular form with a particle size of 1-3 mm.

[0053] The embodiment of the present invention also provides the use of the Rhizopus arrhizus WG01 or the microbial preparation in treating heavy metal cadmium.

[0054] The embodiment of the present invention also provides the use of the Rhizopus arrhizus WG01 or the microbial preparation in promoting phosphorus dissolution.

[0055] Example 1

[0056] Screening and Isolation of WG01 Rhizopus arrhizus Fungal Strain

[0057] The WG01 Rhizopus arrhizus strain contained in the present invention is isolated from wheat leaves grown on cadmium-contaminated soil in Guanzhong.

[0058] The specific operation is as follows: First, rinse the fresh leaves with tap water for 10 minutes to remove the surface attachments; use sterilized scissors in the clean bench to cut the leaf material into about 3 cm long tissue segments; immerse the tissue segments in 75% alcohol by volume for 3 minutes, then put them in 0.1% sodium hypochlorite for 2 minutes, and then put them in 75% alcohol by volume for 1 minute, then take them out and rinse them with sterile water 3 times, each time for about 2 minutes; cut off the incisions at both ends, and use a sterilized scalpel to cut the leaf tissue segments into 3-5mm small cubes visible to the naked eye, a total of 15, and place them on a PDA plate (90mm) with streptomycin sulfate (150mg / L) and ampicillin (100mg / L), seal them, and culture them at a constant temperature of 30℃ under dark conditions for 7 days; observe every other day, wait for the hyphae to grow out at the cut, cut the hyphae and transfer them to a new PDA plate for continued culture, and purify them 2-3 times to obtain a single strain (see Figure 1 ).

[0059] By observing the characteristics of the colonies on the plates, the spore-producing strains were classified into different morphological types according to the spore-producing structure and spore morphology, and the isolated plant endophytic fungi were morphologically identified with reference to the Fungal Identification Manual. After the identified strains were purified, they were inoculated into PDA slants and stored in a 4°C refrigerator.

[0060] The genomic DNA of the strain was extracted using the Solarbio fungal genomic DNA extraction kit, and a small amount of mycelium of the isolated and purified strain was transferred to a new PDA medium for culture at 28°C. The ITS sequence of the strain was determined by random sampling on the PDA medium. The DNA sequence of the reference strain with high sequence similarity to the morphological strain was downloaded from GenBank, and it was found that the closest BLAST comparison species of the strain was Rhizopus arrhizus, with a matching degree of nearly 100%, and it was named WG01.

[0061] The present invention provides a strain of Rhizopus arrhizus WG01, which is deposited in the General Microbiology Center of China Microorganism Culture Collection Administration, with a deposit date of September 9, 2024, a deposit address of No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing, and a deposit number of CGMCC No.41501.

[0062] Example 2

[0063] Experiment on cadmium removal and phosphorus dissolution by Rhizopus arrhizus fungus WG01

[0064] 50 mL of PDB medium was added to a 100 mL shake flask, and the cadmium concentration in the medium was adjusted to 0, 0.5, 1, 2, 3, 4, 5, 10, 15 and 20 mg / L (using CdCl2 solution), and 1 mL of WG01 strain suspension (bacterial concentration 10 8 -10 12 cfu / mL). After one week of cultivation, the dry weight of mycelium was measured and it was found that the growth of the strain was greatly restricted when the cadmium concentration exceeded 4 mg / L. At this concentration, the cadmium removal rate reached 63%, and the cadmium removal per unit mycelium mass was 2.18 mg / g ( Figure 2 ).

[0065] 50 mL of PDB medium was added to a 100 mL shake flask, and the cadmium concentration in the medium was adjusted to 4 mg / L (using CdCl2 solution). [CaH2PO4]2CaSO4 H2O particles were added to the medium, and the phosphorus concentration gradient of the medium system was set to 0, 1, 10, 100 and 200 g / L. Then, 1 mL of WG01 strain suspension (bacterial concentration 10 8 -10 12 cfu / mL). After one week of cultivation, the cadmium and phosphorus concentrations in the culture medium were measured and it was found that the addition of solid insoluble phosphorus could greatly promote the growth of WG01 strain mycelium, increase the removal of heavy metal cadmium and the dissolution of insoluble phosphorus ( Figure 3 ).

[0066] Example 3

[0067] Purchase, identification and isolation of R44 Burkholderia

[0068] The R44 strain contained in the present invention is Burkholderia cepacia, which is obtained by screening and separation from acidic paddy soil in Hunan. The specific operation is as follows: first, add 20g of fresh soil to a conical flask containing 20mL of sterile water, shake and culture at 30°C and 120r / min for 10 days, and stand for 3 days; secondly, take 1mL of the upper solution and transfer it to a sterile flask containing 30mL of LB liquid culture medium, culture it at 30°C and 120r / min for one day, repeat the above strain culture process 3 times and then enrich it. Finally, take 100μL of the suspension and inoculate it on a plate containing LB solid culture medium, culture it overnight at 30°C, transfer a single colony to an LB solid plate, and purify it 2-3 times to obtain a single strain.

[0069] By observing the characteristics of the colonies on the plate, the isolated strains were morphologically identified according to the "Handbook of Fungal Identification". After the identified strains were purified, they were inoculated into the LB solid plate slope and stored in a refrigerator at 4°C.

[0070] The genomic DNA of the strain was extracted using the Solarbio bacterial genomic DNA extraction kit, and the strain was picked, separated and purified and transferred to a new PDA medium for culture at 30°C. The 16S sequence of the strain was randomly sampled on an LB solid plate. The DNA sequence of a reference strain with a high sequence similarity to the morphological strain was downloaded from GenBank, and it was found that the strain had a 100% match with Burkholderia cepacia.

[0071] The DNA sequence of this strain is exactly the same as the gene sequence of Burkholderia bacteria deposited in the China Industrial Microbiology Culture Collection (deposit number CICC10959, deposit date October 13, 2020), so it was not deposited again.

[0072] Example 4

[0073] Experiment on the cadmium fixation ability of Burkholderia R44

[0074] Add 50 mL of LB liquid medium to a 100 mL shake flask, adjust the cadmium concentration in the medium to 4 mg / L (using CdCl2 solution), and inoculate 1 mL of the isolated R44 strain suspension (bacterial concentration 10 8 -10 12 cfu / mL). After one week of culture, the cadmium content in the culture supernatant was measured and it was found that the R44 strain had a strong cadmium fixation ability ( Figure 4 ).

[0075] Example 5

[0076] Co-culture of Burkholderia R44 and Rhizopus arrhizus WG01 and their cadmium fixation ability

[0077] The R44 strain was inoculated on one side of the PDA medium, and the WG01 strain was inoculated on the other side. The inoculation volume was 5 μL and the bacterial concentration was 10 8 -10 12 cfu / mL. After culturing at 30°C for 2-3 days, the growth of the two strains was observed and it was found that the two strains could grow together without antagonism (see Appendix Figure 5 ).

[0078] Add 50 mL of PDB medium to a 100 mL shake flask, adjust the cadmium concentration in the medium to 4 mg / L (using CdCl2 solution), and inoculate 1 mL of R44 strain, WG01 strain, and 0.5 mL of each suspension of the two strains (both bacterial concentrations were 10 8 -10 12 cfu / mL). After one week of cultivation, the cadmium content in the culture supernatant was measured and it was found that the cadmium removal efficiency of the two strains combined was significantly higher than that of a single strain (Appendix Figure 5 ).

[0079] Example 6

[0080] Screening of optimal preparation parameters for microbial preparations

[0081] The microbial growth and fermentation carrier matrix is ​​preferably wheat bran, and wheat straw biochar is compounded according to a mass ratio of (5-20): 1, and water is added to adjust the moisture content. The preferred biochar and its addition ratio can effectively prevent the large-scale agglomeration of wheat bran during the water replenishment process, which is not conducive to the growth of WG01 strain mycelium; the preferred moisture content is 40%-60% to ensure sufficient moisture for microbial growth, of which 60% is the best.

[0082] The preparation method of wheat straw biochar is to anaerobically calcine wheat straw at 550°C for 8h.

[0083] Potato brown sugar water is used as the active carbon and nitrogen source for microbial fermentation, and 400-500 mL of potato brown sugar water is added to every 3 kg of microbial culture substrate (dry weight). The preferred potato brown sugar water here has the advantages of balanced nutrition, simple preparation, and low cost. Preferably, 400-500 mL of potato brown sugar water is added to every 3 kg of microbial culture substrate (dry weight) to create the most suitable nutritional conditions for fungal growth.

[0084] The preparation method of potato brown sugar water is as follows: wash and peel 200g of potatoes, cut them into pieces, put them into a pot, add 1000mL of water, boil them, stir them, and cook them on low heat for 20-30min until the potatoes become soft and cooked; filter them with double-layer gauze or multi-layer gauze to obtain 200ml of clarified potato juice, pour it back into the pot, add 20g of brown sugar, heat and stir to completely dissolve the brown sugar; dispense the prepared potato brown sugar water liquid culture medium into containers such as triangular bottles or test tubes, and then seal and sterilize them with sealing film or cotton plugs. Usually sterilize at 121℃ for about 20min to kill the microorganisms in the culture medium and ensure the sterility of the culture medium.

[0085] The inoculation amount of WG01 Rhizopus arrhizus is 400-500 mL per 3 kg of the above substrate and fermented at 28°C until the fermentation bag is full of fungal hyphae. The preferred seed liquid bacteria concentration here is 10 8 -10 12 The cfu / mL and addition amount are 400-500mL / 3kg. Under this combination of concentration and addition amount, the fungal colonization rate and growth rate are the fastest, which can ensure that the mycelium will fill the culture bag within 5-7 days.

[0086] In the fermentation bag full of fungal hyphae, 400-500 mL of R44 Burkholderia seed solution was inoculated and cultured for 4 hours. The preferred R44 strain inoculation period and seed solution concentration (10 8 -10 12 cfu / mL), inoculation volume (400-500mL / 3kg) and culture time can ensure that the mutual influence of the two strains during growth is minimal and the synergistic effect is maximized. The viable counts of both strains exceed 10 8 cfu / g.

[0087] The fermented product is fully mixed with granular superphosphate (diameter 1-3 mm) at a mass (dry weight) ratio of 1:10. The preferred dry weight ratio of the fermented product to the granular superphosphate is 1:10, which allows the superphosphate to fully absorb the moisture in the fermented product, ensuring that the moisture content of the finished microbial preparation is appropriate and is conducive to storage.

[0088] Example 7

[0089] Field application experiment of microbial preparations

[0090] This example is used to illustrate the application method of microbial preparations. The specific experimental setting is to select farmland soil contaminated by cadmium in Guanzhong (total cadmium 2mg Cd / kg) for wheat field plot test, set up two treatments: control and microbial preparation addition, the plot area is 20m 2, repeated four times. The control treatment applied 8kg N / mu and 6kg P2O5 / mu as basal fertilizer, while the microbial fertilizer was determined to be 50kg / mu with a phosphorus application rate and the nitrogen application rate remained unchanged. Nitrogen fertilizer and microbial preparations were evenly spread on the soil surface and then rotary tilled into the soil, and then wheat was planted. After the wheat was harvested, the wheat grain yield, cadmium and phosphorus content were measured, and the total cadmium, effective cadmium, total phosphorus, available phosphorus, organic matter and total nitrogen content of the soil were measured.

[0091] The results showed that: the application of microbial preparations significantly increased wheat grain yield and phosphorus content, and significantly reduced cadmium content, which met food safety standards; the total cadmium content in the soil changed little, the effective cadmium content significantly decreased, and the total phosphorus, available phosphorus, organic carbon and total nitrogen contents all increased significantly (Table 1).

[0092] Table 1 Effect of field application of microbial preparations

[0093]

[0094] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation methods of the present invention. For ordinary technical users in the relevant field, other different forms of changes or modifications can be made on the basis of the above description. It is not necessary and impossible to list all the implementation methods here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A strain of Rhizopus arrhizus WG01, characterized in that: The strain is deposited in the General Microbiology Center of China Microbiological Culture Collection Administration. The deposit date is September 9, 2024. The deposit address is No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing. The deposit number is CGMCC No.41501.

2. A microbial preparation, characterized in that: It comprises Rhizopus arrhizus WG01 and Burkholderia; the Burkholderia is from the China Industrial Microbiological Culture Collection Center and is numbered CICC10959; the number ratio of Rhizopus arrhizus WG01 to Burkholderia is 1:

1.

3. The method for preparing the microbial preparation according to claim 2, characterized in that: The steps include: inoculating the seed liquid of Rhizopus arrhizus WG01 into a fermentation matrix for fermentation and culturing, inoculating the seed liquid of Burkholderia after the fermentation is completed, and culturing again to obtain a fermentation product; The fermented product is mixed with superphosphate to obtain the microbial preparation.

4. The preparation method according to claim 3, characterized in that: The fermentation substrate includes wheat bran, wheat straw biochar and potato brown sugar water; The preparation method of the fermentation matrix comprises: mixing wheat bran and wheat straw biochar in a mass ratio of (5-20):1, adding water to adjust the water content to 60%, then adding potato brown sugar water in a liquid-to-solid ratio of (400-500) mL:3 kg, and adjusting the water content of the fermentation matrix to 40%-60%.

5. The preparation method according to claim 4, characterized in that: The method for preparing wheat straw biochar is as follows: anaerobically calcining wheat straw at 550° C. for 8 h; The preparation method of the potato brown sugar water is as follows: boiling potatoes with water until they are soft, filtering to obtain clarified potato juice, and adding brown sugar to the potato juice until the brown sugar is completely dissolved; The mass ratio of potatoes to water is 1:5; The volume mass ratio of the potato juice to brown sugar is 20 mL:1 g.

6. The preparation method according to claim 3, characterized in that: The concentration of the seed solution of Rhizopus arrhizus WG01 is 10 8 -10 12 cfu / mL, the inoculation volume is 400-500mL per 3kg fermentation substrate; The fermentation culture conditions are as follows: fermentation at 28° C. for 5 to 7 days.

7. The preparation method according to claim 3, characterized in that: The concentration of the Burkholderia seed solution is 10 8 -10 12 cfu / mL, the inoculation volume is 400-500mL per 3kg fermentation substrate; The condition for the secondary culture is fermentation at 28° C. for 4 hours.

8. The preparation method according to claim 3, characterized in that: The dry weight ratio of the fermentation product to superphosphate is 1:

10.

9. Use of the Rhizopus arrhizus WG01 according to claim 1 or the microbial preparation according to claim 2 in treating heavy metal cadmium.

10. Use of the Rhizopus arrhizus WG01 according to claim 1 or the microbial preparation according to claim 2 in promoting phosphorus dissolution.

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