CN114990000A - Compound microbial agent for degrading DEHP and application of compound microbial agent in preparation of organic fertilizer - Google Patents

Abstract

The invention belongs to the technical field of microorganisms, and discloses a compound microbial agent for degrading DEHP and an application thereof in preparation of organic fertilizers. The composite microbial organic fertilizer CF-PPB provided by the invention can obviously degrade DEHP content of rhizosphere soil in tomato pot culture and Chinese cabbage pot culture, and when the addition amount is 10%, the degradation rate of 40mg/kg DEHP reaches 84.76%. In addition, the microbial organic fertilizer CF-PPB can promote inorganic phosphorus and phosphate rock powder to be converted into soluble phosphate which is easy to absorb by plants, and has obvious growth promotion effect on tomatoes and pakchoi. The composite microbial organic fertilizer CF-PPB provided by the invention is simple to prepare, has safe strain sources, is used as a material for repairing DEHP contaminated soil and promoting plant growth, and has good application prospects.

Description

Compound microbial agent for degrading DEHP and application of compound microbial agent in preparation of organic fertilizer

Technical Field

The invention belongs to the technical field of microorganisms, and particularly relates to a compound microbial agent for degrading DEHP and application thereof in preparation of organic fertilizers.

Background

Diisooctyl phthalate (DEHP) is a widely used plasticizer found in many products, such as toys, infant products, food packaging bags, cosmetics, and also in some medical products such as blood storage bags. DEHP is released to the environment during use or after disposal because it is not covalently bound to the polymer matrix, and thus, is widely distributed in the environment, often in various bodies of water including drinking water, sediments, soils, the atmosphere, landfill leachate, sludge, and the like. In the agricultural production process, DEHP can enter soil along with the use of vegetable greenhouses, land mulching films and the like, so that the DEHP is absorbed and accumulated by plants and then enters the human body through a food chain. DEHP in agricultural soil in china has now reached the milligram/kilogram scale. In addition, DEHP is a typical environmental endocrine stimulant, and if accumulation in the human body reaches a certain threshold, DEHP can cause serious interference to the normal function of the endocrine system in the human body, thereby causing serious adverse effects on the development and reproduction of human beings, the nerve function, the respiratory function, the immune function and the like. The removal of DEHP by microbial degradation is the fastest and safe and effective, including bacteria, fungi, etc. A Rhodococcus isolated from activated sludge has a degrading effect of 98% or more on 200mg/L DEHP (Zhao et al Science of the Total environmental 640-.

Some bacteria and fungi that do not antagonize each other are reported to have a synergistic effect on the degradation of organic pollutants (Zhang et al Chemosphere 273(2021) 129666). The penicillium oxalicum MEM02 in the application has been reported to have the capability of dissolving phosphorus, promoting growth and antagonizing plant pathogenic fungi fusarium graminearum, the pseudomonas MB751 has been reported to have the capability of killing plant pathogenic root-knot nematodes, and the bacillus tequilensis has been reported to have the capability of antagonizing various plant pathogenic fungi.

The compound microbial agent provided by the application is screened out through an antagonism experiment and can coexist. The fungi and the bacteria have synergistic effect, so that the phosphorus can be dissolved and the growth of the soil can be promoted, and the DEHP in the soil can be degraded, thereby achieving the purpose of green and safe planting of crops such as vegetables and the like. And the DEHP in the soil is degraded by using microorganisms, so that the method has the advantages of environmental friendliness, high efficiency, rapidness and the like, and has the effect of promoting the sustainable development of agriculture.

Disclosure of Invention

In order to overcome the defects and shortcomings of the prior art, the invention aims to provide the compound microbial agent for degrading DEHP, and the compound microbial agent has a phosphorus dissolving effect, a DHEP (dehydroepiandrosterone) degrading effect and a growth promoting effect.

The invention also aims to provide application of the compound microbial agent for degrading DEHP.

In order to achieve the purpose, the invention adopts the following technical measures:

a compound microbial agent for degrading DEHP comprises Penicillium oxalicum (Penicillium oxalicum) MEM02 (preservation number: CCTCC NO: M20191002, CN112159761B), Pseudomonas exotrymentalis MB751 (preservation number: CCTCC NO: M2019495, CN110628664A) and Bacillus tequilensis (Bacillus tequilensis).

The composite microbial agent comprises the following bacteria concentrations of Penicillium oxalicum (Penicillium oxalicum) MEM02, Pseudomonas exotrymentalis (Pseudomonas) MB751 and Bacillus tequilensis (Bacillus tequilensis) in the composite microbial agent respectively: 7.0 to 9.0 x 10 ⁸ CFU/g, Pseudomonas sp MB 7511.2-2.0 x 10 ⁹ CFU/g, Bacillus tequilensis 1.0-1.4 × 10 ¹⁰ CFU/g；

The above-mentioned compound microbial inoculum, preferably, its ratio is: 1:2:15.

The above-mentioned compound microbial inoculum, preferably, its ratio is: 1:50:50.

The Bacillus tequilensis is from commercial sources.

A preparation method of a compound microbial fertilizer comprises the following steps:

inoculating penicillium oxalicum MEM02, pseudomonas MB751 and Bacillus tequilensis to a CF-PPB fermentation culture medium to obtain a composite microbial organic fertilizer CF-PPB;

the CF-PPB fermentation medium comprises: 30-40 parts of crushed garden waste, 8-12 parts of wheat bran, 4-6 parts of soybean meal and K ₂ HPO ₄ 0.4 to 0.6 part by weight of KH ₂ PO ₄ 0.4 to 0.6 part of FeSO ₄ 0.004-0.006 part of MgSO 2 ₄ ·7H ₂ 0.04 to 0.06 portion of O, CaCO ₃ 0.04-0.06 part of water and 45-55 parts of water, and sterilizing.

In the above-mentioned method, the Penicillium oxalicum MEM02 is preferably obtained by inoculating a mushroom cake of Penicillium oxalicum MEM02 to a mushroom culture medium (commercially available).

The pseudomonas MB751 and the Bacillus tequilensis are obtained by respectively inoculating the two bacteria into LB liquid culture medium for culture.

The application of the compound microbial agent for degrading DEHP comprises the steps of preparing a microbial organic fertilizer by using the compound microbial agent; or used for degrading DEHP in soil or converting insoluble inorganic phosphorus in soil.

Compared with the prior art, the invention has the following beneficial effects:

1) the penicillium oxalicum MEM02, the pseudomonas MB751 and the Bacillus tequilensis have no obvious antagonistic action and can be prepared into a compound microbial inoculum.

2) The composite microbial inoculum shows a synergistic phosphate-solubilizing effect, has stronger phosphate-solubilizing activity than that of a single strain, wherein the phosphate-solubilizing activity is improved by 21.46 percent compared with that of penicillium oxalicum MEM02, and the phosphate-solubilizing activity reaches 384.39 +/-37.60 mg/L after 24-hour culture.

3) The applicant firstly discovers that the penicillium oxalicum MEM02 has the function of degrading DEHP, and the compound microbial inoculum shows the effect of synergistically degrading DEHP, and has stronger degrading activity than that of a single strain, wherein the degrading activity of the compound microbial inoculum to 1000mg/LDEHP is improved from 83.92% to 93.54% compared with that of penicillium oxalicum MEM 02.

4) The content of the penicillium oxalicum MEM02 spores in the composite microbial organic fertilizer CF-PPB prepared by the method is 8.0 multiplied by 10 ⁸ CFU/g, Pseudomonas sp MB 7511.6X 10 ⁹ CFU/g, Bacillus tequilensis 1.2X 10 ¹⁰ CFU/g。

5) The composite microbial organic fertilizer CF-PPB provided by the invention can obviously degrade DEHP content of rhizosphere soil in tomato pot culture and Chinese cabbage pot culture, and when the addition amount is 10%, the degradation rate of 40mg/kgDEHP reaches 84.76%. In addition, the microbial organic fertilizer CF-PPB can promote inorganic phosphorite powder to be converted into soluble phosphate which is easily absorbed by plants, and has obvious growth promotion effect on tomatoes and pakchoi.

6) Experiments on the egg laying rate of caenorhabditis elegans show that the product of the composite bacterial agent provided by the invention after being degraded by 1000mg/LDEHP has no environmental endocrine toxicity, and the composite bacterial agent has the capability of efficiently and safely degrading DEHP.

7) The composite microbial organic fertilizer CF-PPB provided by the invention is simple to prepare, has safe strain sources, is used as a material for repairing DEHP contaminated soil and promoting plant growth, and has good application prospects.

Drawings

FIG. 1 is a schematic diagram of the degradation effect of different microbial agents on inorganic phosphorus.

FIG. 2 is a schematic diagram of the degradation effect of different microbial agents on DEHP.

Detailed Description

The present invention will be described in further detail with reference to examples and drawings, but the embodiments of the present invention are not limited thereto. The culture medium used in the invention:

LB liquid medium: 5.0g of yeast powder, 10.0g of peptone, 10.0g of sodium chloride and 950ml of distilled water, adjusting the pH value to 7.0, and fixing the volume to 1L by using the distilled water. Sterilizing at 121 deg.C for 20 min.

Potato Dextrose Agar (PDA) medium: 200g of potatoes are cut into small pieces, boiled, filtered by eight layers of gauze, added with 20g of glucose and 15-20 g of agar, added with distilled water to a constant volume of 1L and naturally adjusted to pH. Sterilizing at 115 deg.C for 20 min.

Inorganic phosphorus (Pikovskaya) liquid medium: glucose 10.0g, Ca ₃ (PO ₄ ) ₂ 5.0g，(NH ₄ ) ₂ SO ₄ 0.5g， NaCl 0.2g，MgSO ₄ ·7H ₂ 0.1g of O, 0.2g of KCl, 0.5g of yeast extract and MnSO ₄ ·H ₂ O 0.002g， FeSO ₄ ·7H ₂ O0.002 g, pH 7.0-7.4, 1000ml distilled water. Sterilizing at 115 deg.C for 20 min.

Glucose Yeast Extract (GYE) medium: 10g glucose, 5g yeast extract, 0.6g KH ₂ PO ₄ ，0.5g MgSO ₄ ·7H ₂ O，0.4g K ₂ HPO ₄ ，0.25g CuSO ₄ ·5H ₂ O，0.05g FeSO ₄ ·7H ₂ O，0.05g MnSO ₄ ，0.001 g ZnSO ₄ ·7H ₂ O, 1000ml of distilled water. Sterilizing at 115 deg.C for 20 min.

The formula of the CF-PPB fermentation medium comprises: 35 parts of crushed garden waste, 10 parts of wheat bran, 5 parts of soybean meal and K ₂ HPO ₄ 0.5 part of KH ₂ PO ₄ 0.5 part of FeSO ₄ 0.005 part of MgSO 2 ₄ ·7H ₂ 0.05 part of O, CaCO ₃ 0.05 part and 50 parts of water. Sterilizing at 121 deg.C for 20 min.

Example 1:

confronting experiments with Penicillium oxalicum MEM02, Pseudomonas MB751 and Bacillus tequilensis

Inoculating Penicillium oxalicum MEM02 to PDA plate, culturing at 28 deg.C for 5 days, washing spores with sterile distilled water, and adjusting spore concentration to 1.0 × 10 ⁸ CFU/mL. Pseudomonas MB751 and Bacillus tequilensis were inoculated into LB liquid medium, respectively, and activated overnight at 28 ℃. 5. mu.L of a spore suspension of Penicillium oxalicum MEM02 was dropped on the middle of a PDA plate, and 5. mu.L of Pseudomonas MB751 and Bacillus tequilensis were dropped around the spore suspension, respectively, and cultured at 28 ℃ for 5 days.

The result shows that the penicillium oxalicum MEM02, the pseudomonas MB751 and the bacillus tequilensis have no obvious antagonistic effect and can be prepared into a compound microbial inoculum.

Example 2:

phosphate solubilizing effects of Penicillium oxalicum MEM02, Pseudomonas MB751, Bacillus tequilensis and Complex microbial Agents

The experiments were divided into 5 groups:

penicillium oxalicum MEM02 group: inoculating a penicillium oxalicum MEM02 spore suspension (spore concentration is 1 x 10^7CFU/mL) into an inorganic phosphorus (Pikovskaya) liquid culture medium, wherein the inoculation amount is 1%;

pseudomonas MB751 group: inoculating pseudomonas MB751 bacterial liquid (with effective bacterial concentration of 1 multiplied by 10^9CFU/mL) into inorganic phosphorus (Pikovskaya) liquid culture medium, wherein the inoculation amount is 1%;

group of bacillus tequilensis: inoculating Bacillus tequilensis bacterial liquid (effective bacterial concentration is 1 multiplied by 10^9CFU/mL) into inorganic phosphorus (Pikovskaya) liquid culture medium, wherein the inoculation amount is 1%;

complex microbial inoculum group (CF-PPB group): the method comprises the following steps of inoculating a penicillium oxalicum MEM02 spore suspension (spore concentration is 1 multiplied by 10^7CFU/mL), a pseudomonas MB751 bacterial solution (effective bacterial concentration is 1 multiplied by 10^9CFU/mL), a bacillus tequilensis bacterial solution (effective bacterial concentration is 1 multiplied by 10^9CFU/mL) into an inorganic phosphorus (Pikovskaya) liquid culture medium, wherein the inoculation amounts are 0.5%, 0.25% and 0.25% respectively;

blank control group: inorganic phosphorus (Pikovskaya) liquid medium without added microbial inoculum.

Each group is set with 3 repeats, shaking culture is carried out for 24h at 28 ℃ and 150rpm, and the content of soluble phosphate in the culture medium supernatant is determined by an ammonium molybdate spectrophotometry (GB11893-89 ammonium molybdate spectrophotometry for determining total phosphorus in water).

As shown in FIG. 1, the content of soluble phosphate in the culture supernatant was 316.47. + -. 7.77mg/L after addition of the spores of Penicillium oxalicum MEM 02. After Pseudomonas MB751 is added, the content of soluble phosphate in the culture supernatant is 108.67 + -0.98 mg/L. After the Bacillus tequilensis is added, the content of soluble phosphate in the culture supernatant is 31.56 +/-0.82 mg/L. After the CF-PPB is added, the content of soluble phosphate in the culture medium supernatant is 384.39 +/-37.60 mg/L, which is 21.46 percent higher than that of the Penicillium oxalicum MEM02, and the synergistic phosphorus solubilizing effect of the composite microbial inoculum is demonstrated.

Example 3: DEHP experiments on degradation of Penicillium oxalicum MEM02, Pseudomonas MB751, Bacillus tequilensis and CF-PPB

The experiments were divided into 5 groups:

penicillium oxalicum MEM02 group: inoculating a penicillium oxalicum MEM02 spore suspension (spore concentration is 1 x 10^7CFU/mL) into GYE culture medium, wherein the inoculation amount is 1%;

pseudomonas MB751 group: inoculating pseudomonas MB751 bacterial liquid (with effective bacterial concentration of 1 multiplied by 10^9CFU/mL) into GYE culture medium, wherein the inoculation amount is 1%;

group of bacillus tequilensis: inoculating bacillus tequilensis bacterial liquid (effective bacterial concentration is 1 multiplied by 10^9CFU/mL) into GYE culture medium, wherein the inoculation amount is 1%;

complex microbial inoculum group (CF-PPB group): the method comprises the following steps of inoculating a penicillium oxalicum MEM02 spore suspension (with the spore concentration of 1 x 10^7CFU/mL), a pseudomonas MB751 bacterial solution (with the effective bacterial concentration of 1 x 10^9CFU/mL) and a bacillus tergramicus solution (with the effective bacterial concentration of 1 x 10^9CFU/mL) into GYE culture medium, wherein the inoculation amounts are 0.5%, 0.25% and 0.25% respectively;

blank control group: GYE medium without added microbial inoculum.

Each group was set up in 3 replicates, incubated at 28 ℃ for 5 days with shaking at 150rpm, extracted with dichloromethane from the medium and assayed for DEHP content by high performance liquid chromatography.

As a result, as shown in FIG. 2, Pseudomonas MB751 and Bacillus tequilensis showed no significant DEHP-degrading activity (10-45% degradation rate). The maximum pH value of the penicillium oxalicum MEM02 reaches 83.92% at 1000mg/LDEHP, and the optimum pH value is 6.0. The maximum of CF-PPB to 1000mg/LDEHP reaches 93.54%, and the optimum pH is 6.0, which shows that the compound microbial inoculum has the effect of synergistically degrading DEHP.

Example 4:

preparation of CF-PPB composite microbial organic fertilizer

The cake of Penicillium oxalicum MEM02 was inoculated into a mushroom culture medium (commercially available) and cultured at 28 ℃ for 15 days.

Pseudomonas MB751 and Bacillus tequilensis were inoculated into 1LLB liquid medium, respectively, and cultured at 28 ℃ for 24 hours, and finally the effective bacterial concentration of the Bacillus tequilensis bacterial solution was (2X 10^10CFU/mL) and the effective bacterial concentration of the Pseudomonas MB751 bacterial solution was (1.5X 10^9 CFU/mL).

MEM02 mushroom culture substrate fermentation product (mixture of spore and substrate, effective spore concentration of 1.7 x 10^8 CFU/g). MB751 and Bacillus tequilensis were inoculated at 1% into 1kg of CF-PPB fermentation medium at 5%, and cultured at 28 ℃ for 5 days.

After the culture, the content of the spores of the penicillium oxalicum MEM02 in the CF-PPB fermentation medium was 8.0X 10 ⁸ CFU/g, Pseudomonas MB751 at 1.6 × 10 ⁹ CFU/g, Bacillus tequilensis 1.2X 10 ¹⁰ CFU/g。

Example 5:

tomato potting experiment with CF-PPB (CF-Pentapoly phosphate) compound microbial organic fertilizer

Collecting soil from vegetable farmland of Hubei Jingmen, sieving, dissolving DEHP in acetone, and spraying on soil surface with a spray can to reach soil DEHP content of 50 mg/kg. Each pot was filled with 7.5kg of soil containing DEHP and transplanted into a tomato at the seedling stage. The control group was a blank control without any added inoculum.

The experimental groups were:

1. 15-5-20 inorganic fertilizer (application amount is 0.1 wt%),

2. CF-PPB compound microbial organic fertilizer (application amount is 1.0 wt%) +15-5-20 inorganic fertilizer (application amount is 0.1 wt%),

3. CF-PPB composite microbial organic fertilizer (application amount is 1.0 wt%) +15-0-20 inorganic fertilizer (application amount is 0.1 wt%),

4. CF-PPB compound microbial organic fertilizer (application amount is 1.0 wt%) +15-0-20 inorganic fertilizer (adding 27% phosphate rock powder) (application amount is 0.1 wt%).

Each set was set to 3 replicates. Harvested after 65 days of culture, and the plant height and wet weight were determined. And (3) collecting soil near the rhizosphere of the tomato plant, and measuring the content of soluble phosphorus in the soil by using a sodium bicarbonate extraction-molybdenum-antimony anti-colorimetric method. Extracting DEHP in the soil by using dichloromethane, and detecting the content of the DEHP by using high performance liquid chromatography.

The results show that in the experimental groups applying the CF-PPB compound microbial organic fertilizer, the heights of the tomato plants in the experimental groups applying the CF-PPB compound microbial organic fertilizer and 15-0-20 (adding 27% of phosphate rock powder) are higher than 38.86% of the blank control, and are higher than 15-5-2025.69% of the experimental groups only adding the inorganic fertilizer, the wet weight of the plants is higher than 134.67% of the blank control, and is higher than 15-5-2024.21% of the experimental groups only adding the inorganic fertilizer, the soluble phosphorus content in rhizosphere soil is higher than 128.26% of the blank control, and is higher than 15-5-2011.70% of the experimental groups only adding the inorganic fertilizer, so that the CF-PPB compound microbial organic fertilizer can effectively convert the insoluble inorganic phosphorus (phosphate rock powder) into the soluble phosphorus easily absorbed by tomatoes and promote the growth of the tomatoes. The content of DEHP in tomato rhizosphere soil is obviously reduced in an experimental group applying the CF-PPB compound microbial organic fertilizer, wherein the content of DEHP in the CF-PPB compound microbial organic fertilizer plus 15-0-20 (added with 27% of phosphate rock powder) in the experimental group is reduced by 47.68%.

TABLE 1 CF-PPB composite microbial organic fertilizer tomato potting experiment results

Example 6:

chinese cabbage potting experiment with CF-PPB composite microbial organic fertilizer

Collecting soil from vegetable farmland of Hubei Jingmen, sieving, dissolving DEHP in acetone, and spraying on soil surface with a spray can to make the DEHP content of soil 40 mg/kg. Each pot was filled with 700g of soil containing DEHP, and transplanted into a plantlet-stage pakchoi. The control group was a blank control without any added inoculum.

The experimental groups were:

1. 15-5-20 inorganic fertilizer (application amount is 0.1%);

2. a CF-PPB compound microbial organic fertilizer (the application amount is 1.0 wt%) +15-0-20 inorganic fertilizer (27% of phosphate rock powder is added) (the application amount is 0.1 wt%);

3. CF-PPB composite microbial organic fertilizer (application amount is 5.0 wt%) +15-0-20 inorganic fertilizer (added with 27% phosphate rock powder) (application amount is 0.1 wt%)

4. CF-PPB compound microbial organic fertilizer (application amount is 10.0 wt%) +15-0-20 inorganic fertilizer (added with 27% phosphate rock powder) (application amount is 0.1 wt%).

Each set was set to 3 replicates. After 30 days of culture, the plants were harvested and the wet weight of the plants was determined. And collecting soil near the rhizosphere of the pakchoi plants. Extracting DEHP in the soil by using dichloromethane, and detecting the content of the DEHP by using high performance liquid chromatography.

The result shows that the application amount of the CF-PPB compound microbial organic fertilizer in the experimental group applying the CF-PPB compound microbial organic fertilizer is 10.0 percent and is higher than that of the blank control by 175.00 percent, and the effect of 15-5-20 percent of the inorganic fertilizer is achieved. The experimental group applying the CF-PPB compound microbial organic fertilizer has obvious degradation effect on DEHP in soil, wherein the application amount of the CF-PPB compound microbial organic fertilizer is 10.0%, and the degradation rate reaches 84.76%.

TABLE 2 potted plant experiment results of CF-PPB composite microbial organic fertilizer pakchoi

Example 7:

evaluation of toxicity of product obtained after DEHP degradation of CF-PPB complex microbial inoculum

The GYE medium containing 1000mg/L DEHP was inoculated with the CF-PPB complex inoculum and cultured with shaking at 28 ℃ for 5 days. The medium was extracted twice with the same amount of dichloromethane as the medium, concentrated by a rotary evaporator, and the fermented product was dissolved in 5mL of 0.1% DMSO. The control groups with different concentrations of DEHP were set at 50, 100 and 200mg/L respectively. Synchronizing a large amount of caenorhabditis elegans at the pregnancy, respectively taking 20-30 hatched L1 stage larvae into 48-well plates, adding toxicant with different concentrations, and carrying out toxicant exposure for 48h at 20 ℃. The infected nematodes were individually picked into 48-well plates, 5 per group, and the number of eggs was observed and counted. The experiment was repeated three times.

The result shows that the egg laying rate of the caenorhabditis elegans is continuously reduced along with the increase of the concentration of the DEHP, the degradation product of the CF-PPB composite microbial inoculum after the DEHP is degraded has no obvious influence on the egg laying rate of the caenorhabditis elegans, therefore, the CF-PPB can effectively degrade the environmental endocrine disrupter DEHP, and the influence of the DEHP on the reproduction aspect of the caenorhabditis elegans is effectively reduced.

Table 3 evaluation results of toxicity of products obtained after degrading DEHP by CF-PPB complex microbial inoculum

Claims (7)

1. A compound microbial preparation for degrading DEHP comprises Penicillium oxalicum (B)Penicillium oxalicum) MEM02, accession number: CCTCC NO, M20191002, Pseudomonas (orPseudomonas extremorientalis) MB751, accession No.: CCTCC NO: M2019495 and Bacillus tertalus (B.tertalus) (CCTCC) NOBacillus tequilensis）。

2. The complex microbial inoculant according to claim 1, wherein Penicillium oxalicum (Penicillium sp.), (ii) (i)Penicillium oxalicum) MEM02, Pseudomonas bacterium (M.), (Pseudomonas extremorientalis) MB751 and Bacillus tequilensis (Bacillus tequilensis) The bacterial concentrations in the complex microbial inoculum are respectively as follows: 7.0 to 9.0 x 10 ⁸ CFU/g, Pseudomonas sp MB 7511.2-2.0 x 10 ⁹ CFU/g, Bacillus tequilensis 1.0-1.4 × 10 ¹⁰ CFU/g。

3. The complex microbial inoculant according to claim 2, wherein the ratio of the bacterial concentrations of the penicillium oxalicum MEM02, the pseudomonas MB751 and the bacillus tequilensis is 1:50:50 or 1:2: 15.

4. The use of the complex microbial inoculant defined in claim 1 in the preparation of microbial organic fertilizer.

5. The use of the complex microbial inoculant of claim 1 for degrading DEHP in soil.

6. The use of the complex microbial inoculant of claim 1 for the conversion of poorly soluble inorganic phosphorus in soil.

7. The application of claim 4, wherein the preparation process of the microbial organic fertilizer comprises the following steps: inoculating the compound microbial agent of claim 1 into a CF-PPB fermentation culture medium to obtain a compound microbial organic fertilizer CF-PPB;

the CF-PPB fermentation medium comprises: 30-40 parts of crushed garden waste, 8-12 parts of wheat bran, 4-6 parts of soybean meal and K ₂ HPO ₄ 0.4 to 0.6 part by weight of KH ₂ PO ₄ 0.4 to 0.6 part of FeSO ₄ 0.004-0.006 part of MgSO 2 ₄ ·7H ₂ 0.04 to 0.06 portion of O, CaCO ₃ 0.04-0.06 part of water and 45-55 parts of water, and sterilizing.

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