CN109112082B

CN109112082B - Arthrobacter NX917 and application of adsorbent microbial inoculum thereof in remediation of phthalate-polluted soil

Info

Publication number: CN109112082B
Application number: CN201810855625.4A
Authority: CN
Inventors: 王亚娟; 陶红; 梁浩花; 张小红
Original assignee: Ningxia University
Current assignee: Ningxia University
Priority date: 2018-07-31
Filing date: 2018-07-31
Publication date: 2021-11-02
Anticipated expiration: 2038-07-31
Also published as: CN109112082A

Abstract

The invention relates to arthrobacterium NX917 and application of an adsorbent microbial inoculum thereof in degrading soil phthalate, wherein the arthrobacterium NX917 is classified as Arthrobacter sp, is preserved in China Center for Type Culture Collection (CCTCC) and has the address of eight Los of Lo Jia mountain in Wuchang district of Wuhan city, Hubei, and the preservation number is M2018396. The arthrobacter NX917 provided by the invention has a high-efficiency degradation effect on DBP and DEHP combined pollution of soil, and has a wide application prospect in the field of phthalate-polluted soil remediation.

Description

Arthrobacter NX917 and application of adsorbent microbial inoculum thereof in remediation of phthalate-polluted soil

Technical Field

The invention belongs to the field of agricultural biology, and particularly relates to a high-efficiency degrading bacterium for removing DBP and DEHP in farmland soil, and a preparation method and application of an adsorption bacterium agent thereof.

Background

Phthalic Acid Esters (PAEs), also known as phthalates, are artificially synthesized organic compounds and widely applied to the industries of plastics, fertilizers, pesticides, toys, cosmetics, detergents, coatings and the like, and about 20 to 60 percent of the PAEs are used for processing and manufacturing polyvinyl chloride (PVC) and are used as plasticizers to improve the ductility and flexibility of plastic products. The extensive use of agricultural films is considered to be one of the important sources of phthalates in soil. As the bonds between the phthalate molecules and the plastic molecules are very easily broken by van der waals forces, the phthalate molecules migrate from among the plastic molecules into the soil over time. Phthalates in the soil not only affect the soil quality, the growth and quality of the plants, but also have a certain bio-accumulation effect in the crops, are absorbed by the crops and vegetables to the edible parts to contaminate the food chain, and pose a serious threat to the ecosystem and to human health. Among them, Dibutyl Phthalate (DBP) and Di- (2-ethylhexyl) Phthalate (Di- (2-ethylhexyl Phthalate, DEHP) are two Phthalate compounds with high soil detection rate and high content, and have typical endocrine disturbance and potential 'tri-cause' effect, so that repairing the farmland soil Phthalate pollution, especially the DBP and DEHP pollution, has very important practical significance for guaranteeing the safety of agricultural products and human health.

At present, the organic pollution remediation of soil mainly adopts physical remediation, chemical remediation and biological remediation methods. The bioremediation, particularly the microbial remediation technology, is considered as the most effective and promising pollution treatment technology for remedying the organic contaminated soil because of the advantages of safety, high efficiency, no secondary pollution, good economic benefit and the like, but free microorganisms are easily affected by external factors in the actual environment and the degradation effect of the free microorganisms is difficult to fully exert. The immobilized microorganism technology is adopted, the screened high-efficiency degrading bacteria are fixed in a certain micro environment by utilizing a certain carrier, external adverse factors are shielded, and the degradation rate of phthalate pollutants is finally improved, so that the high-efficiency degrading bacteria can stably play roles in a complex soil environment. Therefore, the high-efficiency degrading bacteria are immobilized by methods such as adsorption and embedding and applied to the polluted soil, so that the degrading effect of the exogenous bacteria on the phthalate is better improved.

Disclosure of Invention

Aiming at the problems, the invention aims to provide a strain with high-efficiency degradation capability aiming at phthalate (especially DBP and DEHP), and further provides an adsorption microbial inoculum for degrading DBP and DEHP in soil.

The phthalate ester related in the invention is dibutyl phthalate (DBP) and di (2-ethylhexyl) phthalate (DEHP), which are the composite pollution of the two.

(1) Screening phthalate degradation bacteria: the invention obtains a strain of Arthrobacter NX917 with a classification name of Arthrobacter sp after a series of screening, which is preserved in China Center for Type Culture Collection (CCTCC) with the address of Bayioney Lodokya mountain in Wuchang district, Wuhan City, Hubei province, the preservation number is CCTCC M2018396, and the preservation date is 2018, 6 months and 25 days.

(2) Of bacterial suspensionsPreparation: culturing DBP and DEHP degrading bacteria to logarithmic phase, cleaning the bacteria with normal saline, and concocting the bacteria with normal saline to obtain bacterial suspension with OD₆₀₀0.8-1.2; the DBP and DEHP degrading bacteria are Arthrobacter NX917 with the classification name of Arthrobacter sp, are preserved in China Center for Type Culture Collection (CCTCC) with the address of Bayinyao mountain in Wuchang district, Wuhan City, Hubei, the preservation number is CCTCC M2018396, and the preservation date is 2018, 6 months and 25 days. In a specific aspect, the physiological saline is a sterilized 0.9% NaCl solution.

(3) The preparation method of the adsorption microbial inoculum comprises the following steps: pulverizing and sieving peanut meal, wheat bran, wood chips and diatomite, drying at 80 ℃, mixing into a composite carrier according to a certain proportion, and performing moist heat sterilization at 120 ℃ for 30 min. Accurately measuring a certain amount of bacterial suspension, uniformly spraying the bacterial suspension on the composite carrier, uniformly mixing, carrying out ventilation fermentation culture for a certain time at a certain temperature, drying at constant temperature, crushing and storing at 4 ℃.

Further, the culture medium of the arthrobacter NX917 in the step (1) is a beef extract peptone culture medium, and the components are as follows: 3g of beef extract, 10g of peptone and 5g of sodium chloride, and adding water to a constant volume of 1000 mL.

Further, the culture conditions of the arthrobacter NX917 in the step (1) are as follows: shaking culture at constant temperature of 200r/min at 25-30 deg.C and pH6.5-7.5 for 24-72 h. Preferably, shaking culture is carried out at the constant temperature of 28 ℃, pH7.0, 170r/min for 24 h.

Further, the method for washing the bacterial cells in the step (2) comprises: centrifuging the culture solution of Arthrobacter NX917 at 3500-4500rpm for 5-15min, discarding the supernatant, resuspending the precipitate with sterilized normal saline, and repeating the steps of centrifuging and resuspending the precipitate 1-3 times.

The application of the arthrobacter NX917 in degrading soil phthalate.

Furthermore, the Arthrobacter NX917 is applied in the form of an adsorption microbial inoculum, the dosage is 0.5-10ml/10g of dry soil, and the water content of the soil is kept to be 55-65% of the maximum water holding capacity in the field in the degradation process.

The invention has the advantages that:

(1) the arthrobacter NX917 provided by the invention has a high-efficiency degradation effect on DBP and DEHP combined pollution of soil, and has a wide application prospect in the field of phthalate-polluted soil remediation.

(2) The microbial inoculum for degrading DBP and DEHP is prepared by adopting the peanut meal, wheat bran, wood chips and diatomite composite carrier as the adsorption material through an adsorption method, and the preparation method is simple to operate.

(3) The immobilized effect of the degrading bacteria is good, the degrading efficiency of DBP and DEHP in soil is high, and the method is suitable for large-area farmland soil phthalate pollution in-situ remediation. After the soil is cultured for 7 days by applying the adsorption bacterium agent, the degradation rate of DBP and DEHP in the soil reaches 89.6 percent and 42.5 percent; in contrast, the degradation rates of the blank control groups of DBP and DEHP were 19.1% and 2.4%, and the degradation rates of DBP and DEHP reached 47.2% and 12.8% when the free bacterium treatment group was between the two groups.

Drawings

FIG. 1 the streaked culture results of Arthrobacter NX 917;

FIG. 2 effect of pH on DBP and DEHP degradation by Arthrobacter NX 917;

FIG. 3 effect of initial concentration on DBP and DEHP degradation by Arthrobacter NX 917;

FIG. 4 effect of rotational speed on DBP and DEHP degradation by Arthrobacter NX 917;

FIG. 5 effect of inoculum size on DBP and DEHP degradation by Arthrobacter NX 917;

FIG. 6 effect of temperature on DBP and DEHP degradation by arthrobacter NX 917;

FIG. 7 shows the influence of the inoculum size on the DBP degradation effect of the microbial inoculum;

FIG. 8 shows the influence of the inoculum size on the DEHP degradation effect of the microbial inoculum;

FIG. 9 is the effect of microbial inoculum fermentation time on DBP degradation effect of microbial inoculum;

FIG. 10 is a graph showing the effect of microbial inoculum fermentation time on the effect of microbial inoculum DEHP degradation;

FIG. 11 shows the degradation performance of the adsorptive microbial inoculum prepared in example 3 on DBP in soil;

FIG. 12 degradation performance of the adsorption bacterial agent prepared in example 3 on DEHP in soil.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail below with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The culture media used in the examples of the present invention were as follows:

beef extract peptone medium: 3g of beef extract, 10g of peptone and 5g of sodium chloride, adding water to a constant volume of 1000mL, and sterilizing at 121 ℃ for 30 min.

Inorganic salt culture medium: k₂HPO₄·3H₂O：1g，NaCl：1g，NH₄NO₃：0.5g，MgSO₄·7H₂O：0.4g，CaCl₂：0.1g，FeCl₃·6H₂O: 0.01g, adding water to a constant volume of 1000mL, and sterilizing at 121 ℃ for 30 min.

DBP/DEHP mineral salts medium: 1ml of each of 5g/L DBP and DEHP acetone solutions were removed in 100ml of sterilized mineral salts medium and placed in a fume hood. After acetone is completely volatilized, the DBP/DEHP inorganic salt culture medium with the concentration of 100mg/L can be obtained (both DBP and DEHP are 100 mg/L).

Example 1 screening and identification of phthalate degrading bacteria

(1) Screening of phthalate degrading bacteria

Collecting a certain amount of soil sample in a vegetable greenhouse in suburbs of the Yinchuan city, accurately weighing 10g of fresh soil sample, adding the fresh soil sample into a triangular flask containing 90mL of distilled water and 10mL of glass beads, placing the triangular flask in a shaking table, oscillating and uniformly mixing at 30 ℃ and 175rpm, and standing for later use.

1mL of the above mixture was inoculated at 1% concentration, added to 100mL of an inorganic salt culture solution having an initial concentration of 100mg/L phthalate (50 mg/L DBP and DEHP), and subjected to shake culture at 30 ℃ in a shaker at 175rpm in the dark for 7 d. The phthalate concentration (including 200mg/L, 500mg/L, 800mg/L, 1000mg/L, 1500mg/L and 2000mg/L) is gradually increased in each transfer, and the transfer is performed once every seven days as a domestication period, and the culture is continuously performed through 6 domestication periods in total.

100 mu L of the final-stage acclimatization solution was spread on an inorganic salt solid plate of 2000mg/L phthalate (DBP and DEHP both 1000mg/L), and then placed in a 30 ℃ biochemical incubator for static culture. After the bacteria can be seen by naked eyes, the growth characteristics of the bacteria are observed, the best growing strain is screened out, and a single bacterial colony is selected and repeatedly streaked and inoculated on a new inorganic salt solid culture medium until the bacteria are purified by microscopic examination.

(2) Identification of phthalate degrading bacteria

The morphological observation of the screened single colony NX917 includes the following culture characteristics: on the solid medium, colony size, ridge shape, transparency, color, migration, texture, morphology, edge characteristics, gloss, and the like were observed. The strain NX917 was cultured on a beef extract peptone medium plate for several days. The bacterial colony is circular, faint yellow, and the viscidity is opaque, and the edge is neat, and the surface uplifts, and moist smooth, the width is generally in 2 ~ 2.5 mm. The specific form is shown in figure 1.

② the strain NX917 sent to Shanghai biological products Limited company for molecular biology identification, and through sequence alignment, the homology with Arthrobacter (Arthrobacter sp.) (GenBank accession number CP017421.1) reaches 100%. The strain NX917 was preliminarily identified as Arthrobacter sp by combining the morphological characteristics of the strain and the result of the 16SrDNA sequence analysis (SEQ ID NO. 1).

Example 2 detection of the ability of Arthrobacter NX917 to degrade phthalates

Preparation of bacterial suspension: selecting smooth and complete Arthrobacter NX917 bacterial colony, inoculating into beef extract peptone liquid culture medium, and shake culturing at 28 deg.C and 170r/min for 24 hr in shaking table. Taking out beef extract peptone liquid culture medium, placing the culture solution in a sterilized centrifuge tube, centrifuging at 4000r/min for 10min at room temperature, and collecting wet thallus. Then washed three times with sterilized physiological saline (0.9% NaCl solution). Finally, the cells were mixed with physiological saline to prepare a bacterial suspension, and the absorbance value OD at a wavelength λ of 600nm was 1.

Determination of the residual amount of DBP/DEHP in the medium with inorganic salts of DBP/DEHP: to 100ml of DBP/DEHP inorganic salt medium was added 30ml of ethyl acetate, shaken for 30min, then transferred to a separatory funnel, shaken for 5min, separated, washed three times with 10ml of ethyl acetate, and the ethyl acetate solution was transferred to a flat bottom flask in its entirety. 4g of anhydrous sodium sulfate, 6g of Florisil and 4g of anhydrous sodium sulfate were added successively to a glass column (1.2 cm. times.30 cm), the column was pre-washed with 10ml of ethyl acetate, the eluate was discarded, and the ethyl acetate extract from the flask was transferred to the column 3 times and eluted with 50ml of ethyl acetate. Collecting all eluates in a heart-shaped flask, rotary evaporating at 35 deg.C for concentration, diluting with chromatographic grade n-hexane to 2.0mL, filtering with organic 0.22 μm filter membrane, and performing gas chromatography mass spectrometry.

DBP and DEHP were measured using a gas chromatography mass spectrometry combination. The chromatographic conditions are as follows: a chromatographic column: rtx-5MS quartz capillary column (30 m.times.0.25 mm. times.0.25 μm); carrier gas: high purity helium gas; sample inlet temperature: 240 ℃; the temperature of the column box is 70 ℃; flow rate: 1 ml/min; the sample amount is 1 ul; and (5) shunting and injecting. Temperature rising procedure: keeping the temperature at 240 ℃ for 5 minutes; the temperature was raised to 280 ℃ at a rate of 5 ℃/min and held for 1 min. The mass spectrum conditions are as follows: the EL ion source has the ion source temperature of 250 ℃, the quadrupole rod temperature of 150 ℃, the interface temperature of 280 ℃ and the solvent delay time of 3 min; and (3) selecting an ion detection SCAN mode to carry out quantitative analysis on the compound within the scanning range of 50-90amu of full-scanning qualitative analysis.

(1) Effect of pH on degradation of DBP and DEHP by Arthrobacter NX917

The medium was sterilized in an inorganic salt medium containing 100mg/L of DBP/DEHP as the initial concentration, and the pH values of the medium were adjusted to 5.0, 6.0, 7.0, 8.0 and 9.0, respectively, using 0.1mol/L HCl and 0.1mol/L NaOH. The strain is cultured for 5 days under the conditions that the inoculation amount of the strain suspension is 2 percent (volume ratio), the temperature is 30 ℃ and the rotating speed is 150r/min, the DBP/DEHP residual quantity is measured, and the degradation rate is calculated.

The degradation rate calculation formula is as follows: the degradation rate (%) ((initial phthalate ester concentration-phthalate ester residual concentration)/initial phthalate ester concentration) × 100%.

The results of fig. 2 show that: the capacity of NX917 strain to degrade phthalate increased first and then decreased with increasing pH, and when pH was 7, NX917 degraded DBP and DEHP at the highest rates of 80.87% and 42.57%, respectively. Therefore, the optimal pH conditions for the strain to degrade DBP and DEHP are 7.

(2) Effect of initial concentration on the degradation of DBP and DEHP by Arthrobacter NX917

After DBP/DEHP inorganic salt culture media with the initial DBP/DEHP concentrations of 50mg/L, 100mg/L, 200mg/L, 300mg/L and 400mg/L are sterilized, 2% of bacterial suspensions are respectively added into DBP/DEHP inorganic salt culture media with different concentrations, shaking culture is carried out for 5 days under the conditions that the pH value is 7, the temperature is 30 ℃ and the rotating speed is 150r/min, the DBP/DEHP residual quantity is measured, and the degradation rate is calculated.

The results of fig. 3 show that: as the initial concentration increases, both the DBP and DEHP degradation rates show a tendency to increase and then decrease. When the initial concentration is 100mg/L, the degradation rate of the strain to DBP and DEHP reaches the highest, and the degradation rate is 73.63% and 62.58% respectively. Therefore, the optimal initial concentration of the strain to degrade DBP and DEHP was 100 mg/L.

(3) Effect of rotational speed on degradation of DBP and DEHP by Arthrobacter NX917

After a DBP/DEHP inorganic salt culture medium with the initial concentration of 100mg/L of DBP/DEHP is sterilized, shaking culture is carried out for 5 days under the conditions that the inoculation amount of bacterial suspension is 2 percent (volume ratio), the pH value is 7 and the temperature is 30 ℃ and at the rotating speeds of 0r/min, 100r/min, 150r/min, 175r/min and 200r/min respectively, the DBP/DEHP residual amount is measured, and the degradation rate is calculated.

The results of fig. 4 show that: under the condition that the rotating speed is 175r/min, the degradation rate of the strain NX917 on DBP and DEHP is the highest and reaches 85.55% and 39.86% respectively. Therefore, the optimal rotating speed for the strain to degrade DBP and DEHP is 175 r/min.

(4) Effect of inoculum size on DBP and DEHP degradation by Arthrobacter NX917

After the DBP/DEHP inorganic salt culture medium with the initial concentration of 100mg/L of DBP/DEHP is sterilized, bacterial suspensions with the volume ratios of 0 percent, 1 percent, 2 percent, 3 percent and 4 percent are respectively added, the mixture is subjected to shaking culture for 5 days under the conditions that the pH value is 7, the temperature is 30 ℃ and the rotating speed is 175r/min, the DBP/DEHP residual quantity is measured, and the degradation rate is calculated.

The results of fig. 5 show that: under the condition that the inoculum size of the bacterial suspension is 4%, the degradation rate of the strain NX917 on DBP and DEHP is the highest and reaches 96.63% and 36.69% respectively. Therefore, the optimal bacterial suspension inoculum for the strains to degrade DBP and DEHP was 4%.

(5) Effect of temperature on degradation of DBP and DEHP by Arthrobacter NX917

After a DBP/DEHP inorganic salt culture medium with the initial concentration of DBP/DEHP of 100mg/L is sterilized, under the conditions that the inoculation amount of a bacterial suspension is 4 percent (volume ratio), the pH value is 7 and the rotating speed is 175r/min, shaking culture is carried out for 5 days at the temperature of 20 ℃, 30 ℃ and 40 ℃ respectively, the DBP/DEHP residual amount is measured, and the degradation rate is calculated.

The results of fig. 6 show that: under the condition of 40 ℃, the strain NX917 has the highest degradation rate on DBP and DEHP, and the degradation rates are respectively 95% and 59.65%. Therefore, the optimal temperature for the strain to degrade DBP and DEHP is 40 ℃.

Example 3 optimization of conditions for preparation of adsorbent bacteria

(1) Preparation of bacterial suspension: arthrobacter NX917 was inoculated into beef extract peptone liquid medium, and cultured at 28 ℃ for 24h at 170 r/min. After the liquid medium was removed, the liquid was dispensed into 50mL sterile centrifuge tubes and centrifuged at 4000rpm for 10 min. Discarding supernatant, resuspending with sterilized normal saline, centrifuging again, cleaning twice, concocting thallus with normal saline to obtain bacterial suspension, and making it OD₆₀₀＝1.0。

(2) The preparation method of the adsorption microbial inoculum comprises the following steps: mixing the carriers according to a certain mass ratio, performing moist heat sterilization at 120 ℃ for 30min, cooling, inoculating 15% bacteria liquid, adding 15% nutrient solution, mixing, subpackaging, ventilating and fermenting at 30 ℃ for 48h, drying at constant temperature, pulverizing at 4 ℃ and storing to obtain the product.

In this embodiment, in order to determine the optimal preparation conditions of the adsorption bacterial agent, carrier ratio, bacterial liquid inoculation amount, and fermentation time are selected as influencing factors, and the preparation conditions are optimized through experiments.

Influence of carrier ratio on bacterial agent living bacterial quantity

As can be seen from Table 1, the ratio of peanut meal, wheat bran, wood flour and diatomite affects the viable count of the microbial inoculum. When the weight ratio of the carrier is 60: 20: 15: 5, the most suitable growth environment is provided for the thalli, the content of viable bacteria is the maximum, and the maximum viable bacteria content reaches 20.3 multiplied by 10⁸cfu/g。

TABLE 1 viable bacteria amount of microbial inoculum prepared by different carrier ratios

② influence of bacterial liquid inoculation amount on phthalate degradation by microbial inoculum

When the carriers m (peanut meal), m (wheat bran), m (wood chips) and m (diatomite) are mixed according to the proportion of 60: 20: 15: 5 and the nutrient solution is 10%, the effect of the bacterial liquid inoculation amount on the DBP and DEHP degradation effect of the microbial inoculum is shown in figures 7 and 8, the effect is highest when the bacterial liquid inoculation amount is 5%, the degradation rates in 3 days, 5 days and 7 days are respectively 89.8%, 93.3% and 99.2%, and the higher the inoculation amount is, the lower the degradation efficiency is. The degradation rate of the microbial inoculum to DEHP is divided into two cases, wherein the inoculation amount is 25% and the degradation rate is the highest at 3 days and 5 days, the inoculation amount is 55.3% and 71.3% respectively, and the degradation rate at 7 days is the highest at 20% and 87.9%.

Influence of fermentation time on degradation of phthalate by microbial inoculum

When carrier m (peanut meal): m (wheat bran): m (wood chips): m (diatomite) is mixed according to the proportion of 60: 20: 15: 5, the effect of the fermentation time on the DBP and DEHP degradation effect of the microbial inoculum is shown in figures 9 and 10 when the inoculation amount is 15% and the nutrient solution amount is 15%, the degradation rate of the microbial inoculum on the DBP is the highest when the fermentation time is 72h, and the degradation rates of 3 days, 5 days and 7 days are respectively 56.3%, 74.3% and 87.1%; the degradation rate of the microbial inoculum to DEHP is the highest when the fermentation time is 72h, and the degradation rates in 3 days, 5 days and 7 days are 29.9%, 55.8% and 75.4% respectively. The result shows that the fermentation time is too short, the reproduction of thalli is influenced, and the number of viable bacteria is less.

Example 4 degradation effect of adsorption inoculum on phthalate in soil

The adsorption microbial inoculum is prepared by using the optimized conditions determined in the embodiment 3, the degradation effects of the free bacterial suspension and the adsorption microbial inoculum prepared in the embodiment on DBP and DEHP in soil are respectively tested, and a blank control is set.

200g of contaminated soil samples (DBP, DEHP content 50mg/kg each) were weighed out into brown sample bottles. Free bacterium group: adding 20mL of bacterial suspension with OD600 of 1.0 (the inoculum size of the bacterial suspension is 10%) into the soil sample; an adsorption microbial inoculum group: 1.5g of the adsorption bacterial agent prepared above (equivalent to the viable bacterial amount of 20ml of bacterial suspension) is added into a soil sample; blank control group: free bacteria and adsorption bacteria agent are not added. And adding sterilized deionized water into each group to ensure that the water content of the soil is 60% of the maximum field water capacity, sealing, placing into a biochemical incubator at 25 ℃ for dark culture, and sampling for analysis when the culture is carried out for 3 rd, 5 th and 7 th days respectively.

After indoor culture for 7 days, the degradation rates of DBP and DEHP in the treatment group with the adsorbent microbial inoculum reach 89.6 percent and 42.5 percent respectively; in contrast, the degradation rates of the blank control groups of DBP and DEHP were 19.1% and 2.4%, respectively, and the degradation rates of DBP and DEHP reached 47.2% and 12.8% between the two groups in the free bacteria treated group (fig. 11 and 12). The adsorption bacterium agent can obviously improve the degradation rate of DBP and DEHP.

It will be understood that modifications and variations can be made by persons skilled in the art in light of the above teachings and all such modifications and variations are intended to be included within the scope of the invention as defined in the appended claims.

Sequence listing

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<120> arthrobacter NX917 and application of adsorbing microbial inoculum thereof in remediation of phthalate-polluted soil

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Claims

1. An adsorption microbial inoculum for degrading DBP and DEHP in soil is prepared by the following preparation method:

(1) preparation of bacterial suspension: culturing DBP and DEHP degrading bacteria to logarithmic phase, cleaning the bacteria with normal saline, and concocting the bacteria with normal saline to obtain bacterial suspension with OD₆₀₀0.8-1.2; the DBP and DEHP degrading bacteria are Arthrobacter NX917 with the classification name of Arthrobacter sp, are preserved in China Center for Type Culture Collection (CCTCC) with the address of Bayinyao mountain in Wuchang district, Wuhan City, Hubei, and have the preservation number of CCTCC M2018396, and the analysis result of the 16SrDNA sequence of the Arthrobacter NX917 is shown in SEQ ID NO. 1;

(2) the preparation method of the adsorption microbial inoculum comprises the following steps: pulverizing and sieving peanut meal, wheat bran, wood chips and diatomite, drying at 80 ℃, mixing into a composite carrier according to a certain proportion, and performing damp-heat sterilization at 120 ℃ for 30 min; weighing a certain amount of bacterial suspension, uniformly spraying the bacterial suspension on the composite carrier, uniformly mixing, carrying out ventilation fermentation culture for a certain time at a certain temperature, drying at constant temperature, crushing and storing at 4 ℃.

2. The use of the adsorptive microbial inoculum of claim 1 in degrading soil phthalate.

3. The application of claim 2, wherein the dosage of the adsorption microbial inoculum is 0.5-10ml/10g of dry soil, and the water content of the soil is kept to be 55-65% of the maximum water capacity in the field in the degradation process.