Preparation method and application of immobilized microbial nanofiber membrane coated seed complex microbial inoculant

Abstract

The invention belongs to the technical field of materials and the field of soil remediation, and particularly relates to a preparation method and application of an immobilized microbial nanofiber membrane coated seed complex microbial inoculant. According to the preparation method, an electrostatic spinning instrument is used for performing electrostatic spinning on a spinning solution containing polyvinyl alcohol, polyvinylpyrrolidone and organic pollution degrading microorganism bacteria, a continuous coating layer is formed on the surface of a seed, and the immobilized microorganism nanofiber membrane coated seed complex microbial inoculant is generated. The immobilized microbial nanofiber membrane coated seed complex microbial inoculant has good biocompatibility and mechanical strength, is eco-friendly, is used for in-situ remediation of organic contaminated soil, reduces stress of organic pollutants on seeds, improves the emergence rate of the seeds and the degradation rate of the organic pollutants, and has great application potential.

Description

Technical Field

[0001] This invention belongs to the fields of materials technology and soil remediation, specifically relating to a method for preparing an immobilized microbial nanofiber membrane-coated seed composite microbial agent and its application. Background Technology

[0002] Petroleum is an indispensable energy source in modern society; however, leaks and other accidents frequently occur during its extraction, transportation, use, and storage, leading to oil pollution problems in the soil environment. On the one hand, once petroleum enters the soil, it damages the soil's physical and chemical properties, harms soil organisms and plant growth, and threatens human health. On the other hand, this pollutant is persistent and hydrophobic, making it difficult to remove from the soil, thus making the remediation of oil-contaminated soil a key and challenging area of ​​research. While chemical and physical remediation methods have achieved some success in domestic and international research, both are not only costly but also cause secondary pollution to the soil. Therefore, eco-friendly bioremediation methods are gradually becoming a research hotspot, especially phytoremediation and microbial remediation. Phytoremediation combined with immobilized microorganisms is a promising method worthy of further research, as it can overcome the difficulties of free-floating microorganisms colonizing and the low efficiency of single-microorganism or phytoremediation methods.

[0003] CN119081940A discloses a composition for remediating heavy metal contaminated soil, its preparation method, and its application. Using polyacrylonitrile, an organic porogen, nano-TiO2, and nano-Fe3O4 as raw materials, a material for immobilizing microorganisms is first prepared by electrospinning followed by high-temperature calcination. This material is then added to an immobilization culture medium, along with 5-10% microbial inoculant, and immobilized at room temperature for 12-24 hours to obtain an immobilized microbial inoculant for remediating heavy metal contaminated soil. Subsequently, the immobilized microbial inoculant was applied to arsenic-contaminated soil remediation experiments. The results showed that the arsenic degradation rate in the immobilized microbial inoculant treatment group was 24.79 percentage points higher than that in the control group. This indicates that immobilized microorganisms have a good remediation effect. However, the carrier preparation and immobilization steps in this study need to be performed in two separate steps, which is relatively cumbersome.

[0004] CN118652878A describes an immobilized microbial agent, a seed coating agent, a combined biological carrier, and their preparation methods and applications. The method involves preparing a biochar-immobilized microbial agent using a one-step growth-adsorption method, with sodium alginate as a binder. Morning glory seeds are placed in a coating machine, and the immobilized microbial agent and binder are sprayed alternately and continuously multiple times to finally obtain a combined biological carrier. This carrier can simultaneously achieve plant and immobilized microbial remediation. However, the separate steps of microbial immobilization and seed coating are relatively cumbersome.

[0005] Electrospinning is a technique that uses a high-voltage electrostatic field to stretch and refine polymer solutions or melts to produce micron- to nano-sized fibers. Nanofiber membranes produced by electrospinning have advantages such as high porosity, large specific surface area, controllable structure and size, and a wide range of raw materials. In recent years, some scholars have applied these technologies to seed coating, and research in agriculture has made some progress, but research on soil remediation is relatively lacking. Summary of the Invention

[0006] This invention provides a method for preparing a seed composite microbial agent coated with an immobilized microbial nanofiber membrane and its application. The invention uses an electrospinning process to form an immobilized microbial nanofiber membrane coating layer on the seed surface, completing the microbial immobilization and seed coating process in one step. The process is simple and the raw materials are inexpensive. It can simultaneously achieve plant-immobilized microbial co-remediation, which is green and efficient. It is a promising sustainable soil remediation method for organic polluted soil.

[0007] The immobilized microbial nanofiber membrane-coated seed composite microbial agent provided by the present invention uses high molecular polymers polyvinyl alcohol and polyvinylpyrrolidone as raw materials. The immobilized microbial nanofiber membrane is prepared by electrospinning instrument, and a vibrating device with a tray is used as a collector so that the nanofiber membrane is received on the seed surface to form a continuous coating layer.

[0008] The technical solution of the present invention is a method for preparing an immobilized microbial nanofiber membrane-coated seed composite agent, the steps of which include: using an electrospinning instrument to electrospin a spinning solution containing polyvinyl alcohol, polyvinylpyrrolidone and organic pollution degrading microorganisms to form a continuous coating layer on the seed surface, thereby generating an immobilized microbial nanofiber membrane-coated seed composite agent. The preparation of the spinning solution containing polyvinyl alcohol, polyvinylpyrrolidone, and organic pollutant-degrading microorganisms includes: mixing an aqueous solution containing polyvinyl alcohol and polyvinylpyrrolidone with a glycerol solution in which the organic pollutant-degrading microorganisms are resuspended.

[0009] The volume ratio of the aqueous solution containing polyvinyl alcohol and polyvinylpyrrolidone to the glycerol solution containing organic pollutant-degrading microorganisms is 2-7:1, preferably 2-5:1, and more preferably 3-4:1.

[0010] In the aqueous solution containing polyvinyl alcohol and polyvinylpyrrolidone, the mass ratio of polyvinyl alcohol to polyvinylpyrrolidone is 1:1-3, preferably 1:1-2, more preferably 1:1.5, and the mass-volume concentration of polyvinyl alcohol is 8-12 g / 100 mL, preferably 10-12 g / 100 mL, more preferably 10-11 g / 100 mL.

[0011] The method for preparing the aqueous solution containing polyvinyl alcohol and polyvinylpyrrolidone includes: dissolving polyvinyl alcohol and polyvinylpyrrolidone in the aqueous solution under heating and stirring, wherein the heating temperature is 70~90℃ and the heating time is 4-8h; the stirring speed is 300~400r / min and the stirring time is 24-26h.

[0012] The glycerol solution containing the organic pollutant-degrading microorganisms was obtained by centrifuging a bacterial suspension with an OD600 value of 1±0.1 at a speed of 4000 r / min and a centrifugation time of 5 min. The glycerol solution was obtained by mixing glycerol and water, with a volume ratio of glycerol to water of 16-20:100, preferably 18:100.

[0013] The organic pollutant degrading microorganisms are selected from any one or any combination of petroleum hydrocarbon degrading bacteria, polychlorinated biphenyl (PCB) degrading bacteria, pesticide degrading bacteria, dye degrading bacteria, phenolic degrading bacteria, and plastic degrading bacteria. Petroleum hydrocarbon degrading bacteria are selected from any one or any combination of Pseudomonas, Acinetobacter, Rhodococcus, Flavobacterium, and Candida, preferably Acinetobacter TX3. PCB degrading bacteria are selected from any one or any combination of Rhodococcus, Burkholderia, and white-rot fungi. Pesticide degrading bacteria are selected from any one or any combination of Pseudomonas, Bacillus, Aspergillus, and Penicillium. Dye degrading bacteria are selected from any one or any combination of white-rot fungi, Bacillus, and Aspergillus. Phenolic degrading bacteria are selected from any one or any combination of Pseudomonas, Alcaligenes, and Acinetobacter. Plastic degrading bacteria are selected from any one or any combination of PET degrading bacteria, Cladosporium, and Penicillium.

[0014] The seeds are pretreated with sodium hypochlorite solution, and then soaked in sodium hypochlorite solution. The concentration of sodium hypochlorite solution and soaking time are adjusted according to the seed type. For example, seeds are soaked in 2% sodium hypochlorite solution for 10 minutes. After soaking, the seeds are repeatedly rinsed with deionized water and then air-dried. The seeds include, but are not limited to, grain seeds, vegetable seeds, cash crop seeds, forage and green manure seeds, fruit seeds, and flower seeds. Grain seeds include, but are not limited to, rice, wheat, corn, barley, sorghum, and millet. Vegetable seeds include, but are not limited to, cabbage, radish, tomato, cucumber, pepper, and spinach. Cash crop seeds include, but are not limited to, rapeseed, peanut, sunflower, soybean, cotton, flax, sugarcane, sugar beet, tea, tobacco, and coffee. Forage and green manure seeds include, but are not limited to, alfalfa, ryegrass, and milkvetch. Fruit seeds include, but are not limited to, apple, pear, peach, grape, plum, apricot, jujube, orange, tangerine, and melon. Flower seeds include, but are not limited to, tulip, lily, rose, zinnia, and petunia.

[0015] The electrospinning parameters are: spinning voltage 15~20kV, spinning distance 10~15cm, solution feed rate 0.4~0.8ml / h, temperature 23~28℃, and humidity 45~58%; preferably, the spinning voltage is 17kV, the spinning distance is 13cm, the feed rate is 0.6ml / h, the temperature is 23℃, and the humidity is 52%.

[0016] The present invention also provides an immobilized microbial nanofiber membrane-coated seed composite microbial agent prepared by the above preparation method.

[0017] The immobilized microbial nanofiber membrane-coated seed composite microbial agent prepared by the above preparation method is used to prepare seeds, and / or products for soil pollution degradation, and / or products for soil remediation, and / or products for soil greening.

[0018] A seed, and / or a product for degrading soil pollution, and / or a product for soil remediation, and / or a product for soil greening, contains an immobilized microbial nanofiber membrane-coated seed composite microbial agent prepared by the above-described preparation method of the present invention.

[0019] The immobilized microbial nanofiber membrane-coated seed composite microbial agent prepared by the above-described preparation method of this invention has broad application prospects in the field of soil remediation, especially in the remediation of organically polluted soil. (1) As an immobilization carrier for microorganisms, porous fiber membranes provide microorganisms with enough attachment sites.

[0020] (2) As a medium to enhance the contact between microorganisms and plants and hydrophobic pollutants.

[0021] (3) As a barrier to protect plant seedlings.

[0022] (4) As an eco-friendly, sustainable, efficient, green, highly biocompatible compound microbial agent that can simultaneously achieve plant-microbe joint remediation.

[0023] (5) There are no negative effects such as inhibition or toxicity between microorganisms, nanofiber membrane carrier materials and seeds.

[0024] The immobilized microbial nanofiber membrane-coated seed composite agent prepared by this invention possesses high biocompatibility, mechanical strength, and biodegradability, simultaneously achieving phytoremediation and microbial remediation. This composite agent uses inexpensive raw materials, is simple to prepare, and can achieve microbial immobilization and seed coating in one step. When applied to petroleum-contaminated soil, the immobilized microbial nanofiber coating layer can slowly release microorganisms, enhance the affinity of microorganisms for hydrophobic petroleum hydrocarbon pollutants, promote seed germination, and protect plant seedlings, thereby improving the efficiency of plant-microbe co-remediation of pollutants. Therefore, the immobilized microbial nanofiber membrane-coated seed composite agent prepared by this invention has the potential to become a green and highly efficient remediation product. Attached Figure Description Figure 1 These are scanning electron microscope images of the polyvinyl alcohol nanofiber membranes prepared in Examples 1-3.

[0025] Figure 2 These are scanning electron microscope images of the polyvinylpyrrolidone nanofiber membranes prepared in Examples 4-6.

[0026] Figure 3 Scanning electron microscope images of the composite nanofiber membranes prepared in Examples 7-9.

[0027] Figure 4 This is a scanning electron microscope image of the immobilized microbial nanofiber membrane prepared in Example 10.

[0028] Figure 5 The aqueous phase degradation results are for the materials prepared in Examples 8 and 10.

[0029] Figure 6 Image of the immobilized microbial nanofiber membrane-coated seed composite bacterial agent prepared in Example 11.

[0030] Figure 7 The results of the germination experiment of the bacterial agent prepared in Example 11 are shown.

[0031] Figure 8 The results of the soil remediation experiment using the microbial agent prepared in Example 11 are shown. Detailed Implementation

[0032] In this invention, the polyvinyl alcohol powder can be prepared by methods known in the art or purchased from the market. Specifically, the polyvinyl alcohol powder used in the embodiments of this invention was purchased from Shanghai Titan Co., Ltd., China, with product number 3301200EB and a molecular weight of 130 kDa.

[0033] In this invention, the polyvinylpyrrolidone powder can be prepared by methods known in the art or purchased from the market. Specifically, the polyvinylpyrrolidone powder used in the embodiments of this invention was purchased from Shanghai Titan Co., Ltd., China, with product number 89088LA, molecular weight of 1000K-1500KDa, and K90.

[0034] The petroleum hydrocarbon-degrading bacteria used in this embodiment are: deposited at the China General Microbiological Culture Collection Center (CGMCC No. 3, No. 1 Beichen West Road, Chaoyang District, Beijing, 100101, China), with accession number CGMCC No. 30200 and deposit date of March 29, 2024. They belong to the Acinetobacter bacterium family and are named TX3. This is described in the invention patent publication text with publication date of August 16, 2024, publication number CN118497039A, entitled "A Petroleum Hydrocarbon Degrading Bacterial Strain, Cultivation Method, Application, and Microbial Agent".

[0035] The technical solutions in the embodiments of the present invention will be further described below with reference to specific embodiments and accompanying drawings, but the embodiments are not intended to limit the present invention.

[0036] Example 1 An immobilized microbial nanofiber membrane for seed coating is prepared by the following steps: (1) Add polyvinyl alcohol powder to deionized water, heat in a water bath at 80°C for 8 hours, stir magnetically at 350 r / h for 24 hours, let stand to defoam and set aside, and obtain a polyvinyl alcohol solution with a concentration of 8% W / V. (2) The polyvinyl alcohol solution obtained in step (1) was spun under the conditions of voltage of 17kV, spinning distance of 13cm, feed speed of 0.6ml / h, temperature of 23℃ and humidity of 52% to obtain a polyvinyl alcohol nanofiber membrane for immobilizing microorganisms.

[0037] Example 2 The preparation steps for immobilized microbial nanofiber membranes for seed coating are basically the same as those in Example 1, except that the concentration of the polyvinyl alcohol solution is 10% W / V.

[0038] Example 3 The preparation steps for immobilized microbial nanofiber membranes for seed coating are basically the same as those in Example 1, except that the concentration of the polyvinyl alcohol solution is 12% W / V.

[0039] Figure 1 Images A and C are scanning electron microscope images of the polyvinyl alcohol nanofiber membranes prepared in Examples 1-3, respectively. The nanofiber membrane with a polyvinyl alcohol concentration of 8% W / V (Figure A) has obvious spindle structures and poor fiber morphology; the spindle structure is significantly reduced in the polyvinyl alcohol fiber membranes with 10% W / V (Figure B) and 12% W / V (Figure C), and the fibers tend to be smoother; from a cost perspective, a polyvinyl alcohol concentration of 10% W / V is preferred.

[0040] Example 4 An immobilized microbial nanofiber membrane for seed coating is prepared by the following steps: (1) Add polyvinylpyrrolidone powder to deionized water, heat in a water bath at 80°C for 8 hours, stir magnetically at 350 r / h for 24 hours, let stand to defoam and set aside, and obtain a polyvinylpyrrolidone solution with a concentration of 13% W / V. (2) The polyvinylpyrrolidone solution obtained in step (1) was spun under the conditions of voltage of 17kV, spinning distance of 13cm, feed speed of 0.6ml / h, temperature of 23℃ and humidity of 52% to obtain a polyvinylpyrrolidone nanofiber membrane for immobilizing microorganisms.

[0041] Example 5 The preparation steps for immobilized microbial nanofiber membranes for seed coating are basically the same as those in Example 4, except that the concentration of the polyvinylpyrrolidone solution is 15% W / V.

[0042] Example 6 The preparation steps for immobilized microbial nanofiber membranes for seed coating are basically the same as those in Example 4, except that the concentration of the polyvinylpyrrolidone solution is 17% W / V.

[0043] Figure 2 Images A and C are scanning electron microscope images of the polyvinylpyrrolidone nanofiber membranes prepared in Examples 4-6, respectively. The 13% W / V (Figure A) polyvinylpyrrolidone nanofiber membrane has a small amount of spindle structure and the fiber surface is not smooth; the fibers at 15% W / V and 17% W / V are relatively smooth and flat, and the 17% W / V (Figure C) polyvinylpyrrolidone nanofiber membrane has a relatively loose structure. Therefore, the preferred polyvinylpyrrolidone concentration is 15% W / V (Figure B).

[0044] Example 7 An immobilized microbial nanofiber membrane for seed coating is prepared by the following steps: (1) Add polyvinyl alcohol and polyvinylpyrrolidone powder to deionized water, heat in a water bath at 80°C for 8 hours, and stir magnetically at 350 r / h for 24 hours to obtain a uniform spinning solution P1, wherein the concentration of polyvinyl alcohol is 5% W / V and the concentration of polyvinylpyrrolidone is 7.5% W / V. (2) Add 18% V / V glycerol solution to the polyvinyl alcohol-polyvinylpyrrolidone spinning solution obtained in step (1), stir evenly and let stand to defoam for later use, and prepare a uniform spinning solution P2, wherein the volume ratio of glycerol solution to spinning solution P1 is 1:6. (3) The spinning solution P2 obtained in step (2) is spun under the conditions of voltage of 17kv, spinning distance of 13cm, feed speed of 0.6ml / h, temperature of 23℃ and humidity of 52% to obtain a composite nanofiber membrane for immobilizing microorganisms.

[0045] Example 8 The preparation steps for immobilized microbial nanofiber membranes for seed coating are basically the same as those in Example 7, except that the volume ratio of glycerol solution to spinning solution P1 is 1:3.

[0046] Example 9 The preparation steps for immobilized microbial nanofiber membranes for seed coating are basically the same as those in Example 7, except that the volume ratio of glycerol solution to spinning solution P1 is 1:2.

[0047] Figure 3 Figures A and C are scanning electron microscope images of the composite nanofiber membranes prepared in Examples 7-9. The composite fiber membrane prepared in Example 7 (Figure A) is relatively dry, while the fiber membranes prepared in Examples 8-9 have an additional glycerol solution present. However, in actual spinning, the fiber membrane prepared in Example 9 (Figure C) has too much residual solvent and is in a hygroscopic state. Therefore, the preferred volume ratio of glycerol solution to spinning solution P1 is 1:3 (Figure B).

[0048] Example 10 An immobilized microbial nanofiber membrane for seed coating is prepared by the following steps: (1) Add 0.3g of polyvinyl alcohol and 0.45g of polyvinylpyrrolidone powder to deionized water, heat in a water bath at 80°C for 8 hours, and stir magnetically at 350r / h for 24 hours to obtain a uniform spinning solution P1. (2) Centrifuge 24 ml of the highly efficient degrading bacteria TX3 with OD600 of 1 at 4000 r / min, then wash twice with 0.9% physiological saline and invert for 1 h to dry. Take 2 ml of 18% V / V glycerol solution to resuspend TX3 to obtain glycerol-TX3 solution. Add glycerol-TX3 solution to spinning solution P1 obtained in step (1), stir evenly and let stand to defoam for later use to obtain uniform spinning solution P2. (3) The spinning solution P2 obtained in step (2) was spun under the conditions of voltage of 17kv, spinning distance of 13cm, feed speed of 0.6ml / h, temperature of 23℃ and humidity of 52% to obtain an immobilized microbial composite nanofiber membrane.

[0049] Figure 4 This is a scanning electron microscope image of the immobilized microbial composite nanofiber membrane prepared in Example 10. Microbial aggregates are visible on the fiber membrane.

[0050] The nanofiber membranes prepared in Examples 8 and 10 were subjected to aqueous phase degradation experiments. Specifically, the fiber membranes were cut into 3×3cm pieces. 2The lumps were added to 10 ml of sterilized MS medium containing 10 g / L diesel oil, with no nanofiber membrane added as the control group. Each treatment group was repeated three times. Degradation experiments were conducted for 7 days in a shaker at 37℃ and 150 rpm. The degradation rate is as follows: Figure 5 As shown, the degradation rate of the treatment group (M treatment group) with the composite nanofiber membrane obtained in Example 8 (5.73%) was not significantly different from that of the CK group (3.77%). However, the degradation rate of diesel fuel of the treatment group (MT treatment group) with the immobilized microbial composite nanofiber membrane obtained in Example 10 (39.57%) was 33.84 percentage points higher than that of the M treatment group, indicating that the immobilized microbial composite nanofiber membrane can exert the performance of the degrading bacteria.

[0051] Example 11 A seed-coated composite microbial agent with immobilized microbial nanofiber membrane, the preparation of which includes the following steps: (1) Same as step (1) in Example 10; (2) Same as step (2) in Example 10; (3) The rapeseed seeds were first soaked in 2% sodium hypochlorite for 10 minutes, rinsed clean and air-dried naturally. The treated seeds were placed in a collector and the spinning solution P2 obtained in step (1) was spun under the conditions of voltage of 17kv, spinning distance of 13cm, pushing speed of 0.6ml / h, temperature of 23℃ and humidity of 52% to collect the fibers onto the continuously jumping seed surface. The spinning time was 6h to obtain the immobilized microbial nanofiber membrane-coated seed composite agent.

[0052] Figure 6 This is an image of the immobilized microbial nanofiber membrane-coated seed composite bacterial agent prepared in Example 11.

[0053] Germination and soil remediation experiments were conducted using the immobilized microbial nanofiber membrane-coated seed composite inoculant (i.e., coated seeds) prepared in Example 11. The specific methods are as follows: 1. Germination experiment: Line a petri dish with filter paper, add an appropriate amount of distilled water, and place 25 units of compound bacterial agent in the dish. Use uncoated rapeseed seeds as the control group. Each treatment was repeated in triplicate. Record the number of germinations each day, calculate the germination potential on day 3, and calculate the germination rate on day 7.

[0054] Figure 7 The germination results showed that the germination potential (97%) and germination rate (100%) of the coated seeds were higher than those of the untreated seeds (germination potential 83%, germination rate 96%). This may be because the nanofiber membrane materials polyvinyl alcohol and polyvinylpyrrolidone are hydrophilic, which allows water to be absorbed and spread on the seed surface. This characteristic is very important in the degradation of hydrophobic petroleum hydrocarbons.

[0055] 2. Soil remediation experiment: Contaminated soil with a concentration of 14.17% was prepared by mixing diesel oil and clean soil. Pot experiments were conducted in a light incubator. The treatment groups are shown in Table 1. Each treatment was repeated three times. The degradation rate was measured on day 30.

[0056] Table 1 Soil remediation experimental treatments Figure 8 Based on the results of the soil remediation experiment, the PMT group, which was coated with immobilized microbial nanofiber membrane seed compound microbial agent, showed a significantly higher degradation rate of soil diesel oil within 30 days (35.38%) than the P treatment group (26.84%) and the CK group (14.74%). This indicates that immobilized microbial nanofiber membrane can help plants resist pollutant stress and improve the pollutant degradation rate.

[0057] The results showed that immobilized microbial nanofiber membranes can reduce the stress of petroleum hydrocarbons on rapeseed seeds and improve the germination rate and petroleum hydrocarbon degradation rate. This invention can simultaneously achieve plant-microbe co-remediation, promoting plant growth; it completes the immobilized microorganisms and seed coating in one step, is simple to operate, and can provide ideas for simplifying microbial seed coating processes, promoting the application of seed coating and electrospinning technologies in ecological restoration.

[0058] The preferred embodiments of the present invention described above are not intended to limit the scope of the present invention. All equivalent changes and modifications made in accordance with the scope of the claims of the present invention should be included within the scope of the present invention.

Claims

1. A preparation method of a microbial nanofiber membrane immobilized seed coating complex microbial inoculant, characterized by the steps of The application relates to a seed coated with a composite microbial agent of immobilized microbial nanofiber membrane, which is prepared by electrospinning a spinning solution containing polyvinyl alcohol, polyvinylpyrrolidone and organic pollution degradation microbial bacteria on the surface of seeds by using an electrostatic spinning instrument. The preparation of the spinning solution containing polyvinyl alcohol, polyvinylpyrrolidone and organic pollution degradation microbial bacteria comprises the following steps: mixing an aqueous solution containing polyvinyl alcohol and polyvinylpyrrolidone with a glycerol solution in which organic pollution degradation microbial bacteria are resuspended. The volume ratio of the aqueous solution containing polyvinyl alcohol and polyvinylpyrrolidone to the glycerol solution in which organic pollution degradation microbial bacteria are resuspended is 2-7:

1.

2. The production method according to claim 1, characterized by, In the aqueous solution containing polyvinyl alcohol and polyvinylpyrrolidone, the mass ratio of polyvinyl alcohol to polyvinylpyrrolidone is 1:1-3, and the mass volume concentration of polyvinyl alcohol is 8-12 g / 100 mL.

3. The preparation method according to claim 1, characterized in that, In the glycerol solution in which organic pollution degradation microbial bacteria are resuspended, the organic pollution degradation microbial bacteria are obtained by centrifuging a bacterial solution with an OD600 value of 1+ / -0.1, and the glycerol solution is obtained by mixing glycerol and water, wherein the volume ratio of glycerol to water is 16-20:

100.

4. The production method according to claim 1, characterized by, The organic pollution degradation microbial bacteria are selected from any one or any combination of petroleum hydrocarbon degradation bacteria, polychlorinated biphenyl degradation bacteria, pesticide degradation bacteria, dye degradation bacteria, phenolic degradation bacteria and plastic degradation bacteria.

5. The preparation method according to claim 1, characterized in that, The electrospinning parameters are as follows: spinning voltage, 15-20 kv; spinning distance, 10-15 cm; solution propulsion speed, 0.4-0.8 ml / h; temperature, 23-28 DEG C; and humidity, 45-58.

6. The method of claim 1, wherein, The seed is pretreated with a sodium hypochlorite solution.

7. The preparation method according to claim 1, characterized in that, The seed coated with the composite microbial agent of immobilized microbial nanofiber membrane is prepared by the preparation method in any one of claims 1-7.

8. A fixed microbial nanofiber membrane coated seed complex microbial inoculant, characterized in that, 9. The seed coated with the composite microbial agent of immobilized microbial nanofiber membrane prepared by the preparation method in any one of claims 1-7 is used for preparing seeds, and / or products for degrading soil pollution, and / or products for soil remediation, and / or products for soil greening. The seed coated with the composite microbial agent of immobilized microbial nanofiber membrane prepared by the preparation method in any one of claims 1-7.

10. A seed, and / or a product for degrading soil pollution, and / or a product for soil remediation, and / or a product for soil greening, characterized by, ​

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