Acinetobacter venetii for broad-spectrum degradation of aromatic organic pollutants and application of acinetobacter venetii

Abstract

The invention discloses a bacterial strain for broad-spectrum degradation of organic pollutants and application of the bacterial strain, the bacterial strain is classified and named as Acinetobacter venetianus, the bacterial strain number is GXGD-YZ-2508, the bacterial strain is preserved in Guangdong Microbial Culture Collection Center on August 27, 2025, the preservation number is GDMCC No: 66869, and the preservation address is the fifth floor, No. 59 building, No. 100 Courtyard, Xianlie Middle Road, Guangzhou City, Guangdong Province. The strain can grow under the condition that the salinity is 3wt%, can efficiently degrade 4-ethylphenol (4-EP), 2, 4-di-tert-butylphenol (2, 4-DTBP) and terephthalic acid (PTA), is suitable for biological treatment of aromatic pollutant-containing wastewater such as refining wastewater and PTA production wastewater, and has the advantages of high treatment efficiency, strong environmental adaptability and the like. The invention provides a novel microbial resource and an effective technical support for biological treatment of refractory aromatic pollutants, and has a wide application prospect.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of environmental microorganism technology, and particularly relates to a broad-spectrum aromatic organic pollutant-degrading Acinetobacter venetianus and application thereof. BACKGROUND

[0002] With the rapid development of petroleum refining, plastic additive manufacturing, polyester production and food chemical industry, a large amount of aromatic organic pollutants with stable structure and significant toxicity contained in industrial wastewater have become a key and difficult problem in current environmental governance. 4-ethylphenol (4-EP), 2,4-di-tert-butylphenol (2,4-DTBP) and terephthalic acid (PTA) are typical representatives among them. These three pollutants are widely distributed in refining wastewater, plastic processing wastewater, antioxidant and coating additive wastewater and PTA polyester production tail water. They not only have high chemical stability and hydrophobicity, but also have strong biological toxicity and high environmental persistence. After entering the water body, they are difficult to degrade and can be enriched in the biological body, causing long-term harm to the ecological system and public health. Related studies have shown that the concentration of some substrates in the environment is even much higher than the safety threshold, which has caused widespread impact on surface water, groundwater and aquatic biological systems.

[0003] 4-ethylphenol is a volatile and strongly odorous phenol derivative, which can be produced by coal tar processing, by-product purification or natural fermentation process. Its sensory threshold is only 0.14-0.62 mg / L, and it is easy to cause odor pollution in water and air. It is often regarded as a "quality defect marker" in the wine, beer, fermented product and food additive industry. After entering the water body, this substance can inhibit the photosynthesis of algae and affect the reproductive system of fish, and it is a typical environmental endocrine disruptor. At present, in the food industry and wastewater treatment, this substance is often removed by activated carbon adsorption, reverse osmosis, molecularly imprinted polymer and other methods, but these technologies can only reduce its concentration to below the olfactory threshold, cannot achieve complete mineralization, and have defects such as long processing period, high cost and easy to cause secondary pollution.

[0004] 2,4-di-tert-butylphenol, as a widely used plastic, rubber, and lubricating oil anti-aging additive, is easily discharged into water bodies with waste liquid during industrial production and product application. Its two bulky tert-butyl substituents in the structure make it have high steric hindrance and oxidation stability, and it is not easy to decompose in the conventional wastewater treatment system. It has been detected by environmental monitoring agencies in rivers, lakes, sewage treatment plant effluent and offshore waters, and the concentration of some points can reach hundreds of micrograms per liter. Studies have shown that this substance can cause intestinal flora disorder, mucosal shedding, inflammatory response, etc. in aquatic organisms, and belongs to the category of emerging toxic and harmful pollutants. At present, there is still a lack of targeted and efficient treatment process in engineering. The existing advanced oxidation method and membrane separation method are mostly aimed at the treatment of total phenol or mixed pollution of phenols, and it is difficult to achieve specific and efficient degradation of 2,4-di-tert-butylphenol.

[0005] Terephthalic acid is an important monomer for the synthesis of polyester bottles, polyester fibers and other products. The mother liquor and tower bottom wastewater generated during its oxidation and rectification process contains a large amount of PTA residue. This type of wastewater has typical characteristics such as high COD, high aromatic structure ratio and low biodegradability, and direct discharge will seriously pollute water bodies. The current mainstream treatment technologies include aerobic / anaerobic biochemical method, Fenton oxidation, ozone catalysis, artificial zeolite adsorption, etc., but there are different degrees of limitations in treatment efficiency, operation cost, system stability and final mineralization degree. For example, the Cu-Ce artificial zeolite catalytic ozone oxidation process can achieve a COD removal rate of more than 80% under optimized conditions, but there are problems such as catalyst loss, high cost, complex operation and poor resource recycling. Although biochemical methods can degrade PTA under certain conditions, they are highly sensitive to reaction time, microbial community composition and water quality fluctuations, and lack of universality.

[0006] In summary, traditional pretreatment, chemical oxidation or membrane separation methods have the problems of complex process, high energy consumption, high operation cost, poor selectivity for pollutants, and residual risk after treatment, etc. when dealing with such pollutants, which are difficult to meet the current increasingly strict industrial wastewater discharge standards. Especially in the high-salt, high-concentration, high-toxicity composite wastewater system coexisting with a variety of structurally different aromatic pollutants (such as 4-ethylphenol, 2,4-di-tert-butylphenol and terephthalic acid), the stability and overall removal efficiency of traditional processes are still difficult to guarantee. In contrast, microbial methods have become an important development direction for the treatment of refractory organic pollutants in recent years due to their mild reaction conditions, green treatment process and low system operation cost. Among them, the construction of functional strains with multi-substrate adaptability is an important technical basis for promoting precise and efficient biological treatment of industrial wastewater.

[0007] However, most publicly reported microbial resources focus on the degradation of single types of pollutants, lacking strains with synergistic degradation capabilities for aromatic pollutants with diverse structures and properties. In particular, no microorganisms with highly efficient degradation performance for three typical organic pollutants—4-ethylphenol, 2,4-di-tert-butylphenol, and terephthalic acid—have been reported in existing biological resource banks. Summary of the Invention

[0008] The purpose of this invention is to address the problems of poor adaptability and low degradation efficiency of existing biological treatment processes for various aromatic organic pollutants, and to provide a strain of Acinetobacter venetianus GXGD-YZ-2508 that can simultaneously degrade 4-ethylphenol, 2,4-di-tert-butylphenol and terephthalic acid.

[0009] To achieve the above objectives, the technical solution provided by the present invention is as follows:

[0010] A strain of Acinetobacter venetianus, which broadly degrades aromatic organic pollutants, was deposited on August 27, 2025, at the Guangdong Provincial Center for Microbial Culture Collection (GDMCC No: 66869). The deposit address is 5th Floor, Building 59, No. 100 Xianlie Middle Road, Guangzhou, Guangdong Province.

[0011] The 16S rDNA nucleotide sequence of Acinetobacter veneritus is shown in SEQ ID NO.1; after growing on LB medium for 24–48 hours, the colonies of Acinetobacter veneritus are milky white to pale yellow, opaque, with neat edges and a smooth, moist surface; under an optical microscope, the individual morphology of the Acinetobacter veneritus is thick and long rod-shaped, about 1.5–2.5 μm long and about 0.5–1.5 μm wide.

[0012] The Acinetobacter veneris described herein has a salt tolerance range of 1–5% (mass fraction of total salt in wastewater calculated as NaCl content), and it has the ability to survive in high-salt environments with a salinity of 1–5 wt% and to efficiently degrade 4-ethylphenol and / or 2,4-di-tert-butylphenol and / or terephthalic acid.

[0013] The present invention also provides the application of the aforementioned Acinetobacter veneris in the treatment of wastewater containing aromatic organic pollutants, wherein the aromatic organic pollutants are any one or more combinations of 4-ethylphenol, 2,4-di-tert-butylphenol and terephthalic acid.

[0014] The total salt content in the wastewater containing aromatic organic pollutants is not higher than 5% by mass.

[0015] Preferably, the total salt content in the wastewater containing aromatic organic pollutants is not higher than 3% by mass.

[0016] The present invention also provides a method for treating wastewater containing aromatic organic pollutants, wherein the Acinetobacter veneris is inoculated into the wastewater containing aromatic organic pollutants to carry out a biological reaction, wherein the aromatic organic pollutants are any one or more combinations of 4-ethylphenol, 2,4-di-tert-butylphenol and terephthalic acid.

[0017] The total salt content in the wastewater containing aromatic organic pollutants is not higher than 5% by mass.

[0018] Preferably, the contents of 4-ethylphenol, 2,4-di-tert-butylphenol, and terephthalic acid in the wastewater containing aromatic organic pollutants are all not higher than 2 g / L.

[0019] More preferably, the content of 4-ethylphenol in the wastewater containing aromatic organic pollutants is not higher than 0.8 g / L, the content of 2,4-di-tert-butylphenol is not higher than 0.65 g / L, and the content of terephthalic acid is not higher than 1.5 g / L.

[0020] The inoculation amount of Acinetobacter venereum was 10. 6 ~10 8 CFU / mL.

[0021] The biological reaction is carried out under aerobic conditions with a temperature of 28–37°C, a pH of 6.5–8.5, and a carbon-to-nitrogen ratio of 5–10:1.

[0022] The Acinetobacter veneris mentioned above exists in a free or immobilized state.

[0023] Preferably, the immobilization involves embedding the Acinetobacter veneris in an immobilization carrier or attaching it to the surface of a packing material.

[0024] Preferably, the Acinetobacter veneris exists in the form of an adhering bacterium to the surface of the packing material. The strain adheres to the surface of the packing material to form a biofilm, thereby improving its degradation efficiency of 4-ethylphenol, 2,4-di-tert-butylphenol, and terephthalic acid.

[0025] Preferably, the filler is an inert filler; more preferably, the filler is a carbon-based carrier.

[0026] The present invention also provides a microbial inoculant comprising the aforementioned Acinetobacter veneris.

[0027] The microbial agent exists in liquid, powder or granule form.

[0028] Preferably, the microbial agent is prepared into powder or granules by fermentation and expansion followed by freeze-drying or spray drying, and stored at room temperature for 12 months, with a cell survival rate of more than 85%.

[0029] Beneficial effects:

[0030] The *Acinetobacter venetianus* GXGD-YZ-2508 strain provided by this invention exhibits high degradation efficiency for three organic pollutants: 4-ethylphenol, 2,4-di-tert-butylphenol, and terephthalic acid. Under conditions of 3 wt% NaCl and an initial 4-ethylphenol concentration of 800 mg / L (COD concentration of 2080 mg / L), the strain can reduce COD to 240 mg / L within 21 days, achieving a 4-ethylphenol removal rate of 88.46%, while simultaneously reducing OD... 600 The concentration remained stable at approximately 0.3. Under conditions of 3 wt% NaCl and an initial 2,4-di-tert-butylphenol concentration of 650 mg / L (COD concentration of 2000 mg / L), the above-mentioned strains could reduce COD to 400 mg / L within 21 days, achieving a 2,4-di-tert-butylphenol removal rate of 80%, while simultaneously reducing OD... 600 The concentration remained stable at approximately 0.3. Under conditions of 3 wt% NaCl and an initial terephthalic acid concentration of 1500 mg / L (COD concentration of 2520 mg / L), the above-mentioned strains could reduce COD to 320 mg / L within 21 days, achieving a terephthalic acid removal rate of 85.19%, while simultaneously reducing OD... 600 The concentration remained stable at approximately 0.2. The broad-spectrum degradation characteristics of this strain make it promising for the treatment of refining wastewater, PTA wastewater, and other aromatic pollutants. The development of this strain not only enriches the bacterial resources for the biological treatment of recalcitrant organic pollutants but also provides a new microbiological solution for the integrated, low-energy-consumption, and efficient purification of complex polluted water bodies such as refining wastewater and PTA wastewater, demonstrating significant engineering application value and promising prospects for wider application. Attached Figure Description

[0031] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, and the advantages of the present invention in the above and / or other aspects will become clearer.

[0032] Figure 1 This is a colony photograph of Acinetobacter venetianus GXGD-YZ-2508, the strain screened in this invention.

[0033] Figure 2The graphs show the degradation effects of strain Acinetobacter venetianus GXGD-YZ-2508 on 4-ethylphenol, 2,4-di-tert-butylphenol, and terephthalic acid under a salinity of 3 wt%.

[0034] Figure 3 The growth curves of strain Acinetobacter venetianus GXGD-YZ-2508 are shown in the figure. The salinity is 3 wt%, and the single carbon sources are 4-ethylphenol, 2,4-di-tert-butylphenol and terephthalic acid. Detailed Implementation

[0035] The present invention will be further described below with reference to the following embodiments. It should be understood that the following embodiments are for illustrative purposes only and are not intended to limit the present invention.

[0036] Unless otherwise specified, the experimental methods used in the following examples follow standard experimental procedures in the field of biology; and the reagents and materials used are commercially available unless otherwise specified.

[0037] The *Acinetobacter venetianus* GXGD-YZ-2508 provided in this invention is a Gram-negative bacterium isolated from high-salt wastewater from a chemical refinery. Under LB agar culture conditions, its colony morphology is characterized as follows: milky white to pale yellow, opaque, with regular edges, and a smooth, moist surface. Under an optical microscope, the individual strains are stout, elongated rods, approximately 1.5–2.5 μm in length and 0.5–1.5 μm in width.

[0038] The salt tolerance range of the Acinetobacter venetianus GXGD-YZ-2508 is 1-5% (mass fraction of total salt in wastewater calculated based on NaCl content).

[0039] The formulation of the BHB basal medium (Bushnell-Haas Broth liquid medium) used in the following examples is shown in the table below. After the drugs were added, the medium was sterilized at 121°C for 20 minutes. After the basal medium cooled to room temperature, the contaminant stock solution, which had been dissolved in ethanol or DMSO beforehand, was added to the target concentration in a sterile operating table.

[0040] Table 1. BHB basal culture medium formulation

[0041] Component Concentration Function KH2PO4 1.0 g / L Buffer, phosphorus source K2HPO4 1.0 g / L Buffer, phosphorus source MgSO4.7H2O 0.2 g / L Magnesium source, auxiliary enzyme activity CaCl2 0.02 g / L Calcium source, cell function maintenance NH4CI 1.0 g / L Nitrogen source FeCl3 0.05 g / L Trace elements, oxidoreductase co-factor NaCl Added as needed Salinity, mimic RO concentrate environment Tween 80 0.5 mL / L Surfactant, promote hydrophobic contaminant dispersion

[0042] Example 1: Isolation, Screening, Domestication, and Identification of Strains

[0043] 10 mL of high-salinity wastewater from a wastewater treatment plant in Jieyang, Guangdong Province, originating from the petroleum refining process, was added to 200 mL of BHB medium (salinity 3%) containing 50 mg / L 4-ethylphenol, 50 mg / L 2,4-di-tert-butylphenol, 25 mg / L m-cresol, and 25 mg / L p-methylphenol. The medium was incubated at 30°C and 180 rpm for 72 hours with shaking to enrich a microbial community capable of degrading aromatic compounds. After incubation, the medium was serially diluted 10-fold. The 10-fold diluted samples were then collected. -5 10 -6 10 -7 0.15 mL of each bacterial suspension was evenly spread onto the surface of BHA (Bushnell-Haas Agar, a solid medium prepared by adding 15-18 g / L agar to BHB basal medium) containing 50 mg / L 4-ethylphenol, 50 mg / L 2,4-di-tert-butylphenol, 25 mg / L m-cresol, and 25 mg / L p-methylphenol. The culture was incubated at 30°C for 3–7 days, and colony growth was observed. Obvious colonies on the plates were picked and purified again using the dilution plating method through multiple rounds of isolation and purification until homogeneous pure cultures were obtained. Several strains capable of growing on the surface of BHA solid plates containing 50 mg / L 4-ethylphenol, 50 mg / L 2,4-di-tert-butylphenol, 25 mg / L m-cresol, and 25 mg / L p-methylphenol were successfully isolated, providing candidate bacterial sources for subsequent domestication and identification.

[0044] Since 4-ethylphenol and 2,4-di-tert-butylphenol are strongly hydrophobic compounds and insoluble in water, they are added as follows: Dissolve 4-ethylphenol and 2,4-di-tert-butylphenol in anhydrous ethanol or DMSO. After thorough stirring and dissolution, prepare stock solutions of 100 g / L for 4-ethylphenol and 2,4-di-tert-butylphenol, respectively. As needed, add the stock solutions directly to BHB or BHA culture media to obtain the required concentration of the culture system.

[0045] To further enhance the tolerance and degradation capacity of the strains to aromatic compounds, all isolated strains underwent four rounds of gradient acclimatization culture in three groups. The acclimatization process used BHB basal medium, with each group supplemented with a single aromatic compound (4-ethylphenol, 2,4-di-tert-butylphenol, and terephthalic acid) at concentrations of 200 mg / L, 300 mg / L, 400 mg / L, and 500 mg / L, respectively, to simulate the environmental pressure of gradually increasing pollutant concentrations. Each round of cultivation lasted 7 days, maintained at 30℃, with a shaking speed of 180 r / min, pH controlled at 7.0, and salinity adjusted to 3% (NaCl content 30 g / L) to adapt to the high-salt environment of the refining wastewater. This method induced the strains to adapt to the corresponding aromatic compounds and enhanced their degradation capacity.

[0046] After four rounds of gradient acclimatization, a dominant strain with good growth and outstanding degradation effects on 4-ethylphenol, 2,4-di-tert-butylphenol, and terephthalic acid was screened from several strains and named GXGD-YZ-2508. GXGD-YZ-2508 was identified as *Acinetobacter venetianus*. This strain was mixed with 25% v / v glycerol protective solution and stored in an ultra-low temperature freezer at -80°C for long-term preservation and subsequent research. The colony morphology of strain GXGD-YZ-2508 is as follows: Figure 1 As shown.

[0047] Example 2: Degradation Experiment of 4-Ethylphenol

[0048] The strain *Acinetobacter venetianus* GXGD-YZ-2508, screened in Example 1, was inoculated into BHB medium with 4-ethylphenol as the sole carbon source to verify its degradation ability for typical recalcitrant pollutants. Specifically, the strain culture was centrifuged at 4000 rpm and 4°C for 10 min, the supernatant was discarded, and the bacterial cells were collected and inoculated into prepared BHB liquid medium, resulting in an initial bacterial concentration of 2 × 10⁻⁶ cells. 7 The medium contains 800 mg / L 4-ethylphenol, has a salinity of 3 wt%, and an initial chemical oxygen demand of 2080 mg / L, all derived from 4-ethylphenol, and is used to simulate a high-concentration organic pollution environment.

[0049] The experimental culture conditions were set at a constant temperature of 30℃ with shaking at 180 rpm to ensure sufficient contact between the bacteria and the contaminants and an aerobic degradation environment. The total culture period was 21 days, during which samples were taken regularly to measure the COD value and optical density (OD) of the culture medium. 600COD (Chemical Oxygen Demand) is used as a measure of the concentration of the organic pollutant 4-ethylphenol to assess the 4-ethylphenol degradation capacity of bacterial strains; OD (Oxygen Demand) is used to assess the 4-ethylphenol degradation capacity of bacterial strains. 600 The COD concentration reflects the microbial cell density in the culture medium and is used to characterize bacterial growth. COD was determined using the potassium dichromate standard method (Determination of Chemical Oxygen Demand in Water - Dichromate Method GB 11914-89) to ensure the scientific validity and comparability of the data. To verify the reliability of COD changes, a blank control group without inoculated strains was set up, with the same culture conditions as the experimental group, to eliminate interference from factors such as the self-degradation or volatilization of 4-ethylphenol on COD removal efficiency. The COD concentration in the control group remained essentially unchanged over 21 days, indicating that pollutant degradation mainly originated from the biodegradation process of the strains.

[0050] The experimental results are shown in Table 2. Figure 2 and Figure 3 As shown, the COD value in the culture medium decreased day by day with the extension of the culture time, and by day 21, the COD value had dropped to 240 mg / L (Table 2). Figure 2 The degradation rate reached 88.46%, indicating that most of the pollutants had been degraded. (Bacterial growth curve) Figure 3 The results show that the bacteria are in an adaptation period for the first 3 days, and the OD... 600 The changes were not significant; days 4 to 9 were the logarithmic growth phase, OD 600 It rose significantly, reaching a maximum of 0.34; it entered a stable period from day 10 to day 15, OD 600 Basically stable, OD from day 16 to day 21 600 A slight decrease indicates that the carbon source is gradually depleted and the bacterial growth tends to stabilize.

[0051] Table 2. Degradation effect of 4-ethylphenol by strain Acinetobacter venetianus GXGD-YZ-2508

[0052]

[0053]

[0054] To more accurately assess the degradation kinetics, COD removal rate (η) was used for quantification, and the calculation formula is as follows:

[0055] Wherein, COD0 is the initial COD concentration (2080 mg / L), COD t Let be the COD concentration on day t. Taking day 21 as an example...

[0056] The above experimental results show that strain GXGD-YZ-2508 can effectively degrade 4-ethylphenol under high salt and high load conditions, exhibiting good degradation performance and environmental adaptability.

[0057] Example 3: Degradation Experiment of 2,4-Di-tert-Butylphenol

[0058] The strain *Acinetobacter venetianus* GXGD-YZ-2508, screened in Example 1, was inoculated into BHB medium with 2,4-di-tert-butylphenol as the sole carbon source to verify its degradation ability for typical recalcitrant pollutants. Specifically, the strain culture was centrifuged at 4000 rpm and 4°C for 10 min, the supernatant was discarded, and the bacterial cells were collected and inoculated into prepared BHB liquid medium, resulting in an initial bacterial concentration of 2 × 10⁻⁶ cells. 7 The medium contains 650 mg / L of 2,4-di-tert-butylphenol, has a salinity of 3 wt%, and an initial chemical oxygen demand of 2000 mg / L, all derived from 2,4-di-tert-butylphenol. It is used to simulate a high-concentration organic pollution environment.

[0059] The experimental culture conditions were set at a constant temperature of 30℃ with shaking at 180 rpm to ensure sufficient contact between the bacteria and the contaminants and an aerobic degradation environment. The total culture period was 21 days, during which samples were taken regularly to measure the COD value and optical density (OD) of the culture medium. 600 COD (Chemical Oxygen Demand) is used as a measure of the concentration of the organic pollutant 2,4-di-tert-butylphenol to assess the 2,4-di-tert-butylphenol degradation capacity of bacterial strains; OD (Oxygen Demand) is used to assess the 2,4-di-tert-butylphenol degradation capacity of bacterial strains. 600 The COD concentration reflects the microbial cell density in the culture medium and is used to characterize bacterial growth. COD was determined using the potassium dichromate standard method (Determination of Chemical Oxygen Demand in Water - Dichromate Method GB 11914-89) to ensure the scientific validity and comparability of the data. To verify the reliability of COD changes, a blank control group without inoculated strains was set up, with the same culture conditions as the experimental group, to eliminate interference from factors such as the self-degradation or volatilization of 2,4-di-tert-butylphenol. The COD concentration in the control group remained essentially unchanged over 21 days, indicating that pollutant degradation mainly originated from the biodegradation process of the strains.

[0060] The experimental results are shown in Table 3. Figure 2 and Figure 3 As shown, the COD value in the culture medium decreased day by day with the extension of the culture time, and by the 21st day, the COD value had dropped to 400 mg / L. Figure 2 This indicates that the pollutants have been largely degraded, with a degradation rate reaching 80%. (Bacterial growth curve) Figure 3 The results show that the bacteria are in an adaptation period for the first 3 days, and the OD... 600Little change; days 4 to 6 are the logarithmic growth phase, OD 600 It rose significantly, reaching a maximum of around 0.35; it entered a stable period on the 7th day, OD 600 The basic structure remains unchanged, and the growth of the bacteria tends to be stable.

[0061] Table 3. Degradation effect of 2,4-di-tert-butylphenol by strain Acinetobacter venetianus GXGD-YZ-2508

[0062]

[0063] To more accurately assess the degradation kinetics, COD removal rate (η) was used for quantification, and the calculation formula is as follows:

[0064] Wherein, COD0 is the initial COD concentration (2000 mg / L), COD t Let be the COD concentration on day t. Taking day 7 data as an example...

[0065] The above experimental results show that strain GXGD-YZ-2508 can significantly remove 2,4-di-tert-butylphenol in a short time and has good biodegradation ability.

[0066] Example 4: Terephthalic Acid Degradation Experiment

[0067] The strain *Acinetobacter venetianus* GXGD-YZ-2508, screened in Example 1, was inoculated into BHB medium with terephthalic acid as the sole carbon source to verify its degradation ability for typical recalcitrant pollutants. Specifically, the strain culture was centrifuged at 4000 rpm and 4°C for 10 min, the supernatant was discarded, and the bacterial cells were collected and inoculated into prepared BHB liquid medium, resulting in an initial bacterial concentration of 2 × 10⁻⁶ cells. 7 The culture medium contains 1500 mg / L terephthalic acid and has a salinity of 3 wt%. The initial chemical oxygen demand of the medium is 2160 mg / L, all derived from terephthalic acid, and is used to simulate a high-concentration organic pollution environment.

[0068] The experimental culture conditions were set at a constant temperature of 30℃ with shaking at 180 rpm to ensure sufficient contact between the bacteria and the contaminants and an aerobic degradation environment. The total culture period was 21 days, during which samples were taken regularly to measure the COD value and optical density (OD) of the culture medium. 600 COD (Chemical Oxygen Demand) is used as a measure of the concentration of terephthalic acid, an organic pollutant, to assess the terephthalic acid degradation capacity of bacterial strains; OD (Oxygen Demand) value. 600The COD concentration reflects the microbial cell density in the culture medium and is used to characterize bacterial growth. COD was determined using the potassium dichromate standard method (Determination of Chemical Oxygen Demand in Water - Dichromate Method GB 11914-89) to ensure the scientific validity and comparability of the data. To verify the reliability of COD changes, a blank control group without inoculated strains was set up, with the same culture conditions as the experimental group, to eliminate interference from factors such as the autodegradation or volatilization of terephthalic acid. The COD concentration in the control group remained essentially unchanged over 21 days, indicating that pollutant degradation mainly originates from the biodegradation process of the strains.

[0069] The experimental results are shown in Table 4. Figure 2 and Figure 3 As shown, the COD value in the culture medium decreased day by day with the extension of the culture time, and by day 21, the COD value had dropped to 320 mg / L (Table 4). Figure 2 This indicates that the pollutants have been largely degraded, with a degradation rate of 85.19%. (Bacterial growth curve) Figure 3 The results show that the bacteria are in an adaptation period for the first 3 days, and the OD... 600 Little change; days 4 to 7 are the logarithmic growth phase, OD 600 It rose significantly, reaching a maximum of around 0.27; it entered a stable period on the 7th day, OD 600 The levels remained essentially unchanged, and bacterial growth tended to stabilize; however, they began to decline slowly from day 14, reaching 0.11 by day 21.

[0070] Table 4. Terephthalic acid degradation effect of strain Acinetobacter venetianus GXGD-YZ-2508

[0071]

[0072] To more accurately assess the degradation kinetics, COD removal rate (η) was used for quantification, and the calculation formula is as follows:

[0073] Wherein, COD0 is the initial COD concentration (2520 mg / L), COD t Let be the COD concentration on day t. Taking day 21 as an example...

[0074] The above experimental results show that strain GXGD-YZ-2508 has a significant ability to degrade PTA and exhibits good adaptability to recalcitrant aromatic dicarboxylic acids.

[0075] The three examples above verified that the Acinetobacter venetianus GXGD-YZ-2508 strain could achieve a broad-spectrum degradation capacity of ≥80% COD removal rate under high-salt BHB culture conditions with 4-ethylphenol, 2,4-di-tert-butylphenol, and terephthalic acid as the sole carbon sources. 4-Ethylphenol, 2,4-di-tert-butylphenol, and terephthalic acid represent structurally simple small-molecule phenols, sterically hindered large phenols, and aromatic dicarboxylic acids, respectively. The GXGD-YZ-2508 strain exhibited stable growth and sustained degradation activity within 21 days, indicating that it has a rich metabolic pathway, strong substrate adaptability, and the potential to serve as an environmental functional bacterium for the treatment of complex aromatic wastewater.

[0076] Example 5: Degradation Experiment of Mixed Substrate

[0077] To verify the combined degradation ability of the strain Acinetobacter venetianus GXGD-YZ-2508 of this invention for three typical recalcitrant pollutants—4-ethylphenol, 2,4-di-tert-butylphenol, and terephthalic acid—the following experiments were conducted:

[0078] The strain *Acinetobacter venetianus* GXGD-YZ-2508, screened in Example 1, was inoculated into BHB medium using 4-ethylphenol, 2,4-di-tert-butylphenol, and terephthalic acid as carbon sources to verify its synergistic degradation ability against a variety of typical recalcitrant pollutants. Specifically, the strain culture was centrifuged at 4000 rpm and 4°C for 10 min, the supernatant was discarded, and the bacterial cells were collected and inoculated into prepared BHB liquid medium, resulting in an initial bacterial concentration of 2 × 10⁻⁶ cells. 7 The culture medium contains 250 mg / L 4-ethylphenol, 220 mg / L 2,4-di-tert-butylphenol, and 500 mg / L terephthalic acid, with a salinity of 3 wt%. The initial chemical oxygen demand of the medium is 2040 mg / L, all derived from the above three pollutants, and is used to simulate a high-concentration organic pollution environment.

[0079] The experimental conditions were as follows: the culture was carried out at a constant temperature of 30℃ with shaking at a rotation speed of 180 rpm to ensure sufficient contact between the bacteria and the contaminants and an aerobic degradation environment. The total experimental period was 21 days, during which samples were taken regularly to measure the COD value and optical density (OD) of the culture medium. 600 COD value. COD value serves as a measure of the degree of degradation of organic pollutants, while OD value... 600 The COD value is used to reflect the growth status of the bacteria. The determination of COD value adopts the potassium dichromate standard method (GB 11914-89) to ensure the scientific validity and comparability of the data.

[0080] To eliminate interference from non-biodegradation factors such as autodegradation or volatilization of the three pollutants, a blank control group was set up, in which the pollutants were cultured under the same conditions without inoculation by the strain. In the blank control group, the COD concentration did not change significantly over 21 days, indicating that the degradation of the pollutants mainly originated from the biodegradation by strain GXGD-YZ-2508.

[0081] The experimental results are shown in Table 5. With the extension of the culture time, the COD value in the culture medium showed a decreasing trend day by day. By day 21, the COD value dropped to 560 mg / L, and the degradation rate reached 72.55%. (See the bacterial growth curve for details.) Figure 3 This indicates that the first 3 days are the bacterial adaptation period, and the OD... 600 The value changes relatively little; it enters the logarithmic growth phase from day 3 to day 6, OD 600 The value increased significantly, reaching a maximum of 0.35; it entered a stable period on the 6th day, OD 600 The OD value remained basically unchanged, and the bacterial growth tended to stabilize; from day 12 onwards... 600 The value began to decline slowly, dropping to 0.12 by day 21.

[0082] Table 5. Degradation efficiency of mixed substrates for strain Acinetobacter venetianus GXGD-YZ-2508

[0083]

[0084] To more accurately assess the degradation kinetics, COD removal rate (η) was used for quantification, and the calculation formula is as follows:

[0085] Wherein, COD0 is the initial COD concentration (2520 mg / L), COD t Let be the COD concentration on day t. Taking day 21 as an example...

[0086] The experimental results show that the strain GXGD-YZ-2508 of this invention can not only effectively degrade single pollutants, but also synergistically degrade 4-ethylphenol, 2,4-di-tert-butylphenol and terephthalic acid in complex multi-pollutant environments, demonstrating its broad-spectrum ability to degrade pollutants and proving its wide application potential in wastewater treatment.

[0087] This invention provides a method and approach for the broad-spectrum degradation of organic pollutants by Acinetobacter veneris, and its applications. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment of the invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technologies.

Claims

1. A strain of Acinetobacter venetianus that broadly degrades aromatic organic pollutants, classified as Acinetobacter venetianus, strain number GXGD-YZ-2508, and preservation number GDMCC No:66869.

2. The application of Acinetobacter veneris according to claim 1 in the treatment of wastewater containing aromatic organic pollutants, wherein the aromatic organic pollutants are any one or more combinations of 4-ethylphenol, 2,4-di-tert-butylphenol and terephthalic acid.

3. The application according to claim 2, characterized in that, The total salt content in the wastewater containing aromatic organic pollutants shall not exceed 5% by mass.

4. A method for treating wastewater containing aromatic organic pollutants, characterized in that, The Acinetobacter veneris described in claim 1 is inoculated into wastewater containing aromatic organic pollutants to carry out a biological reaction; the aromatic organic pollutants are any one or more combinations of 4-ethylphenol, 2,4-di-tert-butylphenol and terephthalic acid.

5. The method according to claim 4, characterized in that, The total salt content in the wastewater containing aromatic organic pollutants shall not exceed 5% by mass.

6. The method according to claim 4, characterized in that, The inoculation amount of Acinetobacter venetum was 10. 6 ~10 8 CFU / mL.

7. The method according to claim 4, characterized in that, The biological reaction was carried out under aerobic conditions with a temperature of 28–37°C, a pH of 6.5–8.5, and a carbon-to-nitrogen ratio of 5–10:

1.

8. The method according to any one of claims 4 to 7, characterized in that, The Acinetobacter veneris described exists in either a free or immobilized state.

9. A microbial inoculant, characterized in that, It includes Acinetobacter veneris as described in claim 1.

10. The microbial agent according to claim 9, characterized in that, The microbial agent exists in liquid, powder, or granular form.

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