Perfluorooctane sulfonamide-degrading bacterium c11 and application thereof

Abstract

The application provides a perfluorooctane sulfonamide degrading bacterium C11 and application thereof, and belongs to the technical field of biological treatment of environmental organic pollutants. The application provides a Comamonas testosteroni C11, and the preservation number of the Comamonas testosteroni C11 is CCTCC NO: M2023247. The application separates a high-efficiency PFOSA degrading strain, the Comamonas testosteroni C11, from a sewage sample of a sewage treatment plant in Jilin City, Jilin Province, China, and the Comamonas testosteroni C11 can efficiently degrade PFOSA, and the degradation rate is as high as 64.6%. The discovery of the Comamonas testosteroni C11 provides strain resources for efficient biological degradation of PFOSA, and provides a basis for application of the strain to purification of PFAS contaminated environment.

Description

Technical Field

[0001] This invention belongs to the field of biological treatment technology for environmental organic pollutants, specifically relating to a perfluorooctane sulfonamide degrading bacterium C11 and its applications. Background Technology

[0002] Per- and poly-fluoroalkyl substances (PFAS) are synthetic persistent organic pollutants with unique physicochemical properties, such as high surface activity, strong thermal stability, chemical stability, and hydrophobicity and oleophobicity. These properties contribute to the widespread use of PFAS in industrial and consumer applications, including surfactants, fire-fighting foams, pesticides, and aerospace. Perfluorooctane sulfonate (PFOS) is the most representative PFAS, widely used due to its excellent hydrophobic and oleophobic properties in surface coatings. However, due to its long-distance migration in the environment, extremely high environmental persistence, and bioaccumulation in organisms, it is widely detected in the atmosphere, water, soil, and in plants, animals, and humans. Studies have found that PFOS can enter the environment through secondary transformation of its precursors (preFOS), and can enter organisms through inhalation, digestion, and skin contact, causing developmental toxicity, neurotoxicity, and immunotoxicity. Therefore, PFOS and related substances have received significant attention both domestically and internationally. In 2009, the Stockholm Convention on Persistent Organic Pollutants officially listed PFOS as a persistent organic pollutant.

[0003] The most widely detected PFOS precursors fall into two main categories: perfluorooctane sulfonamidoethanol (FOSE) and perfluorooctane sulfonamides (FOSA). Perfluorooctane sulfonamides (PFOSA) are a typical neutral PFOS precursor and an important intermediate in the degradation of high-molecular-weight precursors. Studies have shown that PFOSA is far more cytotoxic than PFOS and possesses strong lethal and teratogenic effects; therefore, PFOSA is referred to as a developmental neurotoxin.

[0004] Currently, there are two main methods for removing PFOS precursors: physicochemical methods and biodegradation methods. While physicochemical methods have some removal efficiency, they are often limited in practical applications due to their demanding conditions, high energy consumption, complex operation, and serious secondary pollution. Biodegradation methods, as a cost-effective and environmentally friendly remediation technology for removing organic matter from the environment, have attracted widespread attention due to their potential environmental protection role in practical pollution applications. With the deepening of research on PreFOS biodegradation, researchers have screened PFOS-degrading bacteria from PFAS-contaminated environments, such as the *Microphytella* genus, which has a degradation rate of 14.6%. Hyphomicrobium Acinetobacter spp. with a degradation rate of 27% Acinetobacter However, the strains currently reported either have limited ability to degrade high concentrations of PFOSA or can only degrade low concentrations of PFOSA, which is still somewhat different from the requirements for efficient PFOSA removal. Furthermore, the microbial resources available for aerobic PFOSA degradation are currently very limited. Therefore, it is necessary to isolate more efficient degrading strains from the environment. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the purpose of this invention is to provide a *Trichomonas testis* strain C11 that can efficiently degrade PFOSA.

[0006] The objective of this invention is achieved through the following technical solution: This invention provides a strain of *Trichomonas testis* (…). Comamonas testosteroni The preservation number of *Trichomonas testis* C11 is CCTCC NO: M 2023247.

[0007] Preferably, the nucleotide sequence of the 16S rRNA of *Trichomonas testis* C11 is shown in SEQ ID NO.1.

[0008] This invention provides a perfluorooctane sulfonamide-degrading bacterial solution, comprising *Trichomonas testis* C11 as described in the above technical solution.

[0009] This invention provides a method for preparing the bacterial culture described in the above technical solution, comprising the following steps: The *Trichomonas vaginalis* C11 was cultured in a culture medium to obtain a bacterial solution.

[0010] Preferably, the culture temperature is 20℃~40℃; the culture time is 24h~72h.

[0011] This invention provides the application of *Trichomonas vaginalis* C11 as described in the above-described technical solution, the bacterial solution as described in the above-described technical solution, or the bacterial solution prepared by the preparation method described in the above-described technical solution in the degradation of perfluorooctane sulfonamide.

[0012] This invention provides a method for degrading perfluorooctane sulfonamides using *Trichophyton mentagrophytes* C11 as described in the above-described technical solution, the bacterial solution as described in the above-described technical solution, or the bacterial solution prepared by the preparation method described in the above-described technical solution, comprising: Testosterone-bearing Trichomonas vaginalis C11 or its bacterial culture was mixed with perfluorooctane sulfonamide to degrade perfluorooctane sulfonamide.

[0013] This invention also provides a method for screening perfluorooctane sulfonamide degrading bacteria, comprising the following steps: The supernatant of the sewage sample was inoculated into a culture medium and cultured to obtain a mixed culture solution; The mixed bacterial culture was sequentially subcultured in a gradient medium with perfluorooctane sulfonamide as the sole carbon source to obtain an enriched culture. The enriched culture was serially diluted and spread onto solid culture medium containing perfluorooctane sulfonamide. Single colonies with good growth were streaked and purified to obtain perfluorooctane sulfonamide degrading bacteria.

[0014] Preferably, the mass concentrations of perfluorooctane sulfonamide in the inorganic salt gradient culture medium with perfluorooctane sulfonamide as the sole carbon source are 0.005 g / L, 0.01 g / L, 0.015 g / L and 0.02 g / L, respectively.

[0015] Preferably, the mass concentration of perfluorooctane sulfonamide in the solid culture medium containing perfluorooctane sulfonamide is 0.005~0.01 g / L.

[0016] The beneficial effects of this invention are: This invention provides a strain of *Trichomonas testis* C11, whose preservation number is CCTCC NO: M 2023247. This invention isolated a highly efficient PFOSA-degrading strain—*Trichomonas testis* C11—from wastewater samples from a wastewater treatment plant in Jilin City, Jilin Province, China. Through morphological observation, 16S rRNA gene sequence alignment, and whole-genome sequence analysis, a strain with high PFOSA degradation ability was obtained and identified as *Trichomonas testis*. The *Trichomonas testis* C11 provided by this invention can efficiently degrade PFOSA, with a degradation rate as high as 64.6%. The discovery of *Trichomonas testis* C11 in this invention provides a strain resource for the efficient biodegradation of PFOSA and lays the foundation for the application of this strain in the purification of PFAS-contaminated environments.

[0017] Biological Preservation Instructions Testosterone-bearing Trichomonas vaginalis ( Comamonas testosteroniC11 was deposited on March 6, 2023, at the China Center for Type Culture Collection (CCTCC), located at Luojia Mountain, Bayi Road, Wuchang District, Wuhan City, Hubei Province, with accession number CCTCC NO: M 2023247. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 Phylogenetic tree of Trichomonas testis C11; Figure 2 OD of strain C11 under different pH conditions 600 picture; Figure 3 The degradation of PFOSA by strain C11 under different pH conditions is shown in the diagram. Figure 4 OD of strain C11 under different temperature conditions 600 picture; Figure 5 The degradation of PFOSA by strain C11 under different temperature conditions is shown in the diagram. Figure 6 OD of strain C11 under different initial PFOSA concentrations 600 picture; Figure 7 Degradation of PFOSA by strain C11 under different initial PFOSA concentrations; Figure 8 A standard curve of PHOSOSA concentration; Figure 9 The growth curve of strain C11 in inorganic salt medium with an initial PFOSA concentration of 30 mg / L is shown. Figure 10 The degradation of PFOSA by strain C11 in an inorganic salt medium with an initial PFOSA concentration of 30 mg / L is shown in the figure. Figure 11 This is a colony morphology diagram of strain C11 in an inorganic salt medium with PFOSA as the sole carbon source. Figure 12 This is a scanning electron microscope image of strain C11. Detailed Implementation

[0020] This invention provides a strain of *Trichomonas testis* (…). Comamonas testosteroniThe preservation number of *Trichomonas testis* C11 is CCTCC NO: M 2023247.

[0021] This invention provides a perfluorooctane sulfonamide-degrading bacterium. In this invention, the perfluorooctane sulfonamide-degrading bacterium was selected from wastewater from an aeration tank in a sewage treatment plant as the screening source. Enrichment, screening, separation, and purification were performed using a culture medium with perfluorooctane sulfonamide as the sole carbon source, resulting in a perfluorooctane sulfonamide-degrading strain, which was molecularly identified as *Trichophyton mentagrophytes* (testosterone-bearing bacterium). Comamonas testosteroni The *Trichomonas testis* strain C11 was developed and named accordingly. In this invention, *Trichomonas testis* C11 is deposited at the China Center for Type Culture Collection (CCTCC) on March 6, 2023, with accession number CCTCC NO: M 2023247. The *Trichomonas testis* C11 provided by this invention can utilize perfluorooctane sulfonamide (PFOS) as the sole carbon source for metabolism and growth. At 30°C, *Trichomonas testis* C11 achieves a 64.6% degradation rate of PFOS within 14 days, demonstrating excellent degradation capabilities for PFOS. The *Trichomonas testis* C11 provided by this invention can be applied to the remediation of environments polluted by perfluorinated compounds, providing resources for bioremediation efforts.

[0022] In this invention, *Trichomonas testis* C11 is a Gram-negative, rod-shaped, non-flagellated bacterium with a cell size of approximately 0.5 μm × 2 μm. In this invention, *Trichomonas testis* C11 colonies formed on LB solid medium are raised, glossy, round, white, opaque, and have regular edges. In inorganic salt medium with PFOSA as the sole carbon source, *Trichomonas testis* C11 colonies are smaller, approximately 4 mm in diameter, raised, glossy, round, milky white, opaque, and have regular edges. Physiological and biochemical tests show that *Trichomonas testis* C11 can secrete oxidase and catalase; the pyruvate produced by the decomposition of glucose by *Trichomonas testis* C11 is further decomposed into diacetyl; and *Trichomonas testis* C11 can reduce nitrate to nitrite.

[0023] The nucleotide sequence of the 16S rRNA of Trichomonas vaginalis C11 described in this invention is 1464 bp in length, as shown in SEQ ID NO.1.

[0024] In this invention, the nucleotide sequence of SEQ ID NO.1 is as follows:

[0025] The 16S rRNA sequence of *Trichomonas testis* C11 was compared with sequences in the GenBank database using BLAST analysis, and the constructed molecular identification cluster map is shown below. Figure 1 As shown. A comparison with the NCBI database revealed that the 16S rRNA sequence of *Trichomonas testis* C11 is similar to... Comamonas testosteroni Clustering within the same branch with a similarity of 100%, this indicates that C11 belongs to... Comamonas testosteroni .

[0026] This invention provides a perfluorooctane sulfonamide-degrading bacterial solution, comprising *Trichomonas testis* C11 as described in the above technical solution.

[0027] This invention provides a method for preparing the perfluorooctane sulfonamide-degrading bacterial solution described in the above-mentioned technical solution, comprising the following steps: The *Trichomonas vaginalis* C11 was cultured in a culture medium to obtain a bacterial solution.

[0028] This invention does not impose any special restrictions on the type of culture medium; any conventional culture medium in the art that can ensure the survival of *Trichomonas testis* C11 is acceptable. The *Trichomonas testis* C11 provided by this invention can utilize other forms of carbon sources besides PFOSA as the sole carbon source. In this invention, the culture medium can be LB medium. The culture method described in this invention can be light-protected culture; the culture temperature is preferably 20℃~40℃, more preferably 20℃~35℃, even more preferably 25℃~35℃, and more preferably 30℃. The culture time is preferably 24~72h, more preferably 24h. In this invention, the culture is preferably carried out to the logarithmic growth phase. The culture process is preferably accompanied by shaking. The shaking speed is preferably 130~150 r / min, more preferably 150 r / min. After the culture is completed, the OD of the bacterial solution obtained by this invention is... 600 The value is preferably 0.5~1.3, more preferably 0.6~1.0, and even more preferably 0.8. After obtaining the bacterial solution, the bacterial solution of the present invention is preferably stored in 25% glycerol and kept in a refrigerator at -80°C for later use.

[0029] This invention provides the application of *Trichomonas vaginalis* C11 as described in the above-described technical solution, the bacterial solution as described in the above-described technical solution, or the bacterial solution prepared by the preparation method described in the above-described technical solution in the degradation of perfluorooctane sulfonamide.

[0030] This invention provides a method for degrading perfluorooctane sulfonamide using *Trichophyton mentagrophytes* C11 as described in the above-described technical solution, the bacterial solution as described in the above-described technical solution, or the bacterial solution prepared by the preparation method described in the above-described technical solution, comprising: Testosterone-bearing Trichomonas vaginalis C11 or its bacterial culture was mixed with perfluorooctane sulfonamide to degrade perfluorooctane sulfonamide.

[0031] In this invention, the *Trichophyton mentagrophytes* C11 is preferably a suspension of *Trichophyton mentagrophytes* C11. In this invention, the preparation method of the bacterial suspension preferably includes the following steps: After rinsing the bacterial cells of *Trichomonas testis* C11 from the culture medium, the rinsed bacterial cells were resuspended to obtain a bacterial suspension. The OD of the bacterial suspension 600 The value is 0.8~1.0.

[0032] When collecting *Trichomonas testis* C11 cells from a culture medium, this invention preferably collects cells from the logarithmic growth phase of the culture medium. The preferred method of collection is centrifugation, with a preferred centrifugation speed of 6000-8000 r / min, more preferably 8000 r / min; the preferred centrifugation time is 3-5 min, more preferably 5 min. After centrifugation, this invention preferably removes the supernatant and collects the precipitate to obtain *Trichomonas testis* C11 cells. After obtaining the *Trichomonas testis* C11 cells, this invention washes the cells. The preferred washing solution is 1×PBS. This invention does not have a specific limitation on the amount of PBS used; a conventional amount is sufficient. After washing, this invention preferably centrifuges the washing solution and collects the precipitate to obtain the washed cells. The centrifugation speed of this invention is preferably 6000-8000 r / min, more preferably 8000 r / min; the centrifugation time is preferably 3-5 min, more preferably 5 min. The rinsing is preferably performed 3 times. After rinsing, the rinsed bacterial cells are resuspended to obtain a bacterial suspension. The resuspension solution is preferably 1×PBS. In this invention, the OD of the bacterial suspension is... 600 The value is 0.8 to 1.0, preferably 1.0.

[0033] After obtaining the bacterial suspension, the present invention preferably mixes the bacterial suspension with perfluorooctane sulfonamide to degrade the perfluorooctane sulfonamide.

[0034] After obtaining the bacterial suspension, the present invention preferably inoculates the bacterial suspension into a perfluorooctane sulfonamide inorganic salt culture medium for the degradation of perfluorooctane sulfonamide. In the present invention, the pH value of the perfluorooctane sulfonamide inorganic salt culture medium is preferably 5.0-9.0, more preferably 6.0-8.0, and more preferably 7.0; the initial mass concentration of perfluorooctane sulfonamide in the perfluorooctane sulfonamide inorganic salt culture medium is 10-50 mg / L, preferably 20-40 mg / L, and more preferably 30 mg / L; the degradation temperature is 20-40℃, preferably 25-35℃, and more preferably 30℃. In the present invention, at 30℃ and an initial PFOSA concentration of 20 mg / L, strain C11 can grow well within a pH range of 5.0-9.0, and within a pH range of 6.0-8.0, the degradation effect of strain C11 on PFOSA increases with the growth rate of the strain OD. 600 The degradation rate of PFOSA by strain C11 increases with increasing pH, reaching a maximum of 55.5% at pH 7.0. As the pH continues to rise to 9.0, the PFOSA degradation rate gradually decreases. In this invention, strain C11 can grow within the temperature range of 20℃ to 40℃, with the optimal growth temperature being 20℃ to 35℃. In this invention, at pH 7.0 and an initial PFOSA concentration of 20 mg / L, within the temperature range of 20℃ to 30℃, the degradation rate of PFOSA by strain C11 increases with increasing OD. 600 The OD value increased with increasing temperature; strain C11 showed the best PFOSA degradation effect at 30℃, with a degradation rate of 55.5%; when the temperature was further increased to 40℃, the PFOSA degradation rate was 5.65%. In this invention, at 30℃ and pH 7.0, within the initial PFOSA concentration range of 10~30 mg / L, the OD value... 600 The OD value increases with increasing concentration, and the degradation rate of PFOSA also increases. At an initial concentration of 30 mg / L, the OD value... 600 The strain reached a maximum value of 1.382, and also achieved an optimal degradation rate of 64.6% for PFOSA. When the initial PFOSA concentration exceeded 30 mg / L, the OD... 600 The value decreased with increasing concentration, and the degradation efficiency of strain C11 also decreased with increasing initial PFOSA concentration.

[0035] This invention also provides a method for screening perfluorooctane sulfonamide degrading bacteria, comprising the following steps: The supernatant of the sewage sample was inoculated into a culture medium and cultured to obtain a mixed culture solution; The mixed bacterial culture was sequentially subcultured in a gradient medium with perfluorooctane sulfonamide as the sole carbon source to obtain an enriched culture. The enriched culture was serially diluted and spread onto solid culture medium containing perfluorooctane sulfonamide. Single colonies with good growth were streaked to obtain perfluorooctane sulfonamide degrading bacteria.

[0036] In this invention, the supernatant of a sewage sample is inoculated into a culture medium and cultured to obtain a mixed bacterial culture solution.

[0037] In this invention, the wastewater sample is preferably wastewater from the aeration tank of a wastewater treatment plant. The wastewater volume is preferably 50-100 mL, more preferably 100 mL. The wastewater sample is preferably allowed to stand for 10-20 minutes, more preferably 20 minutes, before being collected as supernatant. After obtaining the wastewater supernatant, it is inoculated into a culture medium. The culture medium is preferably LB medium. The culture method is preferably light-protected. The culture temperature is preferably 20-40°C, more preferably 20-35°C, even more preferably 25-35°C, more preferably 30°C. The culture time is preferably 24-72 h, more preferably 48 h. The culture process is preferably accompanied by shaking, with the shaking speed preferably 130-150 r / min, more preferably 150 r / min.

[0038] After obtaining the mixed culture medium, the present invention sequentially passages the mixed culture medium in a gradient medium with perfluorooctane sulfonamide as the sole carbon source to obtain an enriched culture medium.

[0039] In this invention, the mass concentration of perfluorooctane sulfonamide (PFOS) in the gradient culture medium using PFOS as the sole carbon source preferably increases gradually. The preferred mass concentrations of PFOS in the gradient culture medium are 0.005 g / L, 0.01 g / L, 0.015 g / L, and 0.02 g / L, respectively. In this invention, the subculture preferably includes a first subculture, a second subculture, a third subculture, and a fourth subculture. Preferably, the first subculture is performed in a culture medium with a PFOS concentration of 0.005 g / L. During the first subculture, a mixed culture broth is inoculated into the PFOS medium and cultured to obtain the first subculture broth. After obtaining the first subculture broth, the second subculture is preferably performed. Preferably, the second subculture is performed in a culture medium with a PFOS concentration of 0.01 g / L. In this invention, during the second subculture, 5 mL of the first subculture medium is inoculated into perfluorooctane sulfonamide medium to obtain the second subculture medium. After obtaining the second subculture medium, this invention preferably performs a third subculture. This invention preferably performs the third subculture in a medium with a perfluorooctane sulfonamide concentration of 0.015 g / L. In this invention, during the third subculture, 5 mL of the second subculture medium is inoculated into perfluorooctane sulfonamide medium to obtain the third subculture medium. After obtaining the third subculture medium, this invention preferably performs a fourth subculture. This invention preferably performs the fourth subculture in a medium with a perfluorooctane sulfonamide concentration of 0.02 g / L. In this invention, during the fourth subculture, 5 mL of the third subculture medium is inoculated into perfluorooctane sulfonamide medium to obtain the fourth subculture medium. In this invention, the fourth subculture medium is the enrichment culture medium.

[0040] The culture conditions in the subculture process described in this invention are preferably the same. The subculture process is preferably carried out during culture; the temperature of the subculture is preferably 20~40℃, more preferably 25~35℃, and even more preferably 30℃; the subculture time is preferably 24~72h, and even more preferably 72h; the culture process is preferably accompanied by oscillation, and the oscillation speed is preferably 130~150r / min, and even more preferably 150r / min.

[0041] After obtaining the enriched culture medium, the present invention performs serial dilution of the enriched culture medium and spreads it on solid culture medium containing perfluorooctane sulfonamide. The well-grown single colonies are then streaked and purified to obtain perfluorooctane sulfonamide degrading bacteria.

[0042] After obtaining the enriched culture medium, this invention preferably performs serial dilutions using 1 mL of the enriched culture medium. This invention preferably uses physiological saline for serial dilutions. After serial dilutions, this invention preferably obtains dilutions of 10... -3 10 -4 10 -5 10 -6 10 -7 10 -8 The invention provides a gradient dilution culture medium. After obtaining the above-mentioned gradient dilution culture medium, the present invention spreads the gradient dilution culture medium separately on a solid culture medium containing perfluorooctane sulfonamide for spread culture. In the present invention, the mass concentration of perfluorooctane sulfonamide in the solid culture medium containing perfluorooctane sulfonamide is preferably 0.005~0.01 g / L, more preferably 0.01 g / L. The spread culture of the present invention is preferably a culture; the temperature of the spread culture is preferably 20~40℃, more preferably 25~35℃, more preferably 30℃; the subculture time is preferably 1 week. After the spread culture is completed, the present invention performs streak culture on well-grown single colonies, more preferably streak culture on well-grown single colonies of different morphologies. The culture medium for streak culture of the present invention is preferably a solid culture medium containing perfluorooctane sulfonamide; the mass concentration of perfluorooctane sulfonamide in the solid culture medium containing perfluorooctane sulfonamide is preferably 0.005~0.01 g / L, more preferably 0.01 g / L. The streak plating culture described in this invention is preferably carried out in the dark; the temperature of the streak plating culture is preferably 20~40℃, more preferably 25~35℃, and even more preferably 30℃. In this invention, the streak plating time for one session is preferably 3 days. If a single colony cannot be obtained after the first 3-day streak plating culture, this invention preferably continues to purify the single colony by streak plating culture. This invention preferably repeats the streak plating culture until a single colony is finally obtained. The single colony obtained by this invention is a perfluorooctane sulfonamide degrading bacterium.

[0043] In this invention, the culture medium used in the screening method for perfluorooctane sulfonamide degrading bacteria is an inorganic culture medium as the base medium. Preferably, the inorganic salt culture medium comprises: 4.26 g / L NaHPO4, 2.65 g / L KH2PO4, 0.2 g / L MgSO4·7H2O, 1.5 g / L NH4Cl, 0.01 g / L FeSO4, and 0.02 g / L CaCl2. The pH of the inorganic salt culture medium is preferably 7.0-7.2. If the inorganic salt culture medium is a liquid medium, preferably, 4.26 g NaHPO4, 2.65 g KH2PO4, 0.2 g MgSO4·7H2O, 1.5 g NH4Cl, and 0.01 g FeSO4 are weighed, the pH is adjusted to 7.0-7.2, then 0.02 g CaCl2 is added, and finally deionized water is added to bring the volume to 1000 mL. In this invention, if the inorganic salt culture medium is a solid culture medium, it is preferable to add 2% agar powder to the inorganic salt liquid culture medium. In this invention, the inorganic salt liquid culture medium and the inorganic salt solid culture medium are respectively autoclaved at 121°C for 20 minutes. In this invention, after sterilization, the inorganic salt solid culture medium is cooled to approximately 55°C, poured into plates near an alcohol lamp flame, and allowed to cool and solidify before use.

[0044] This invention screened three strains capable of degrading perfluorooctane sulfonamide using the aforementioned screening method. These strains are C1, C11, and C12, with C11 exhibiting the highest degradation efficiency for perfluorooctane sulfonamide.

[0045] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the accompanying drawings and embodiments, but these should not be construed as limiting the scope of protection of the present invention.

[0046] The culture medium and stock solution in the following examples: (1) LB medium: Weigh 10g NaCl, 10g tryptone, 5g yeast extract, adjust pH to 7.0~7.4, add deionized water to make up to 1000mL, and autoclave at 121℃ for 20min.

[0047] (2) Inorganic salt culture medium: Weigh 4.26g NaHPO4, 2.65g KH2PO4, 0.2g MgSO4·7H2O, 1.5g NH4Cl, and 0.01g FeSO4, adjust the pH to 7.0~7.2, then add 0.02g CaCl2, and finally add deionized water to make up to 1000mL. Autoclave at 121℃ for 20min.

[0048] (3) Starch culture medium: Weigh 5g tryptone, 5g NaCl2, 5g beef powder, 10g soluble starch, adjust pH to 7.2, add deionized water to make up to 1000mL, and autoclave at 115℃ for 15min.

[0049] (4) Methyl red medium: Weigh 5g tryptone, 5g glucose, 6.55g K2HPO4·3H2O, adjust pH to 7.2, add deionized water to make up to 1000mL, and autoclave at 115℃ for 15min.

[0050] (5) VP medium: Weigh 5g tryptone, 5g glucose, 6.55g K2HPO4·3H2O, adjust pH to 7.2, add deionized water to make up to 1000mL, and autoclave at 115℃ for 15min.

[0051] (6) Nitrate reduction medium: Weigh 6g of nitrate medium, add deionized water to make up to 1000mL, and autoclave at 121℃ for 20min.

[0052] (7) Hydrogen sulfide medium: Weigh 32.5g of lead acetate medium, add deionized water to make up to 1000mL, and autoclave at 115℃ for 15min.

[0053] (8) Lead acetate solution: Weigh 10g of lead acetate, add 90mL of deionized water, sterilize with a 0.45μm filter membrane, and store in a refrigerator at 4℃ for later use.

[0054] (9) Methyl red reagent: Weigh 0.1g of methyl red, add 300mL of 95% ethanol, and add deionized water to make up to 500mL.

[0055] (10) Solid culture medium: Add 2% agar powder to the liquid culture medium, autoclave, and wait for it to cool to about 55°C. Pour the plate into a clean bench near the flame of an alcohol lamp, and let it cool and solidify before use.

[0056] (11) Preparation of PFOSA stock solution: Dissolve 0.01g of PFOSA standard in 10mL of methanol to prepare PFOSA with a concentration of 1g / L. After the methanol has completely evaporated, sterilize it by passing it through a 0.22μm organic membrane and store it in a refrigerator at 4℃ for later use.

[0057] Unless otherwise specified, the inoculation volume for the following technical solutions is 2% of the culture medium volume.

[0058] Example 1 1. Screening of PFOSA-degrading bacteria A 100 mL wastewater sample was collected from the aeration tank of a wastewater treatment plant in Jilin City, Jilin Province. After standing for 30 min, 5 mL of the supernatant was inoculated into a 100 mL Erlenmeyer flask containing 50 mL of LB medium. The flask was incubated at 30℃ and 150 rpm for 48 h with shaking. Then, 5 mL of the culture was added to an inorganic salt medium containing PFOSA as the sole carbon source (initial PFOSA concentration: 0.005 g / L). The medium was then incubated at 30℃ and 150 rpm for 72 h with shaking to obtain the first subculture medium. 5 mL of this first subculture medium was then transferred to fresh inorganic salt medium with an initial PFOSA concentration of 0.01 g / L and incubated at 30℃ and 150 rpm. The culture was shaken and cultured for 72 h to obtain the second passage culture medium. 5 mL of the second passage culture medium was transferred to fresh inorganic salt medium with an initial PFOSA concentration of 0.015 g / L, and the culture was shaken and cultured at 30 °C and 150 r / min for 72 h to obtain the third passage culture medium. 5 mL of the third passage culture medium was transferred to fresh inorganic salt medium with an initial PFOSA concentration of 0.02 g / L, and the culture was shaken and cultured at 30 °C and 150 r / min for 72 h to obtain the fourth passage culture medium, which is the enrichment culture medium.

[0059] Take 1 mL of enrichment culture medium and serially dilute it with physiological saline, then take 1 mL of the diluted medium at a factor of 10. -3 10 -4 10 -5 10 -6 10 -7 10 -8 The culture medium was spread onto solid inorganic salt agar plates containing 0.01 g / L PFOSA and incubated at 30°C for one week. Single colonies of different morphologies that grew well were then streaked onto solid inorganic salt agar plates containing 0.01 g / L PFOSA. After 3 days of streaking, colonies were transferred to fresh solid agar plates for further incubation until only single colonies were observed on the plates, thus obtaining a pure culture.

[0060] Three degrading strains were successfully isolated and purified by collecting wastewater samples from a wastewater treatment plant. All three strains could grow on inorganic salt solid medium with PFOSA as the sole carbon source. The three degrading strains were numbered C1, C11, and C12, and their colony characteristics on the solid medium were observed, as shown in Table 1.

[0061] Table 1. Colony morphology of the three degrading bacteria obtained from screening on inorganic salt solid medium with PFOSA as the sole carbon source.

[0062] 2. The degradation effect of the three PFOSA-degrading bacteria obtained from the screening was tested on PFOSA.

[0063] The three purified degrading bacteria were inoculated into inorganic salt medium with PFOSA as the sole carbon source. The initial PFOSA concentration was 20 mg / L, pH 7.0, 30℃, and shaken for 7 days. The remaining amount of PFOSA in the degradation system was measured, and the degradation rate was calculated.

[0064] The formula for calculating the degradation rate is: Degradation rate % = (C 降解前 -C 降解后剩余 ) / C 降解前 ×100%.

[0065] The degradation effects of the three screened degrading bacteria on PFOSA are shown in Table 2.

[0066] Table 2 shows the degradation effects of the three screened degrading bacteria on PFOSA.

[0067] As shown in Table 2, after 7 days, the degradation rates of PFOSA by C1, C11 and C12 were 16.8%, 29.75% and 11.15%, respectively. Among them, C11 showed better degradation effect on PFOSA, so strain C11 will be used as the subject of subsequent experimental research.

[0068] Example 2 Physiological and physicochemical properties of strain C11 1. Colony characteristics of strain C11 Strain C11 was inoculated into LB solid medium and incubated at 30°C for 24 h. The colony morphology was then observed. Strain C11 was also inoculated into an inorganic salt medium with PFOSA as the sole carbon source and incubated at 30°C for 24 h. The colony morphology of strain C11 in the inorganic salt medium with PFOSA as the sole carbon source is shown below. Figure 11 As shown.

[0069] When strain C11 was inoculated into LB solid medium and incubated at 30°C for 24 hours, the colonies appeared raised, glossy, round, white, opaque, and with regular edges. When strain C11 was inoculated into an inorganic salt medium with PFOSA as the sole carbon source, the colonies were smaller, approximately 4 mm in diameter, raised, glossy, round, milky white, opaque, and with regular edges.

[0070] 2. Cell morphology and physiological and biochemical characteristics of strain C11 1) Gram staining test: The isolated and purified PFOSA-degrading bacterial strain C11 was inoculated onto LB solid medium and streaked. It was then incubated at 30℃ for 24 hours. The colony morphology was observed, and single colonies were picked for Gram staining. First, a small drop of physiological saline was added to a clean glass slide. A single colony was picked and mixed with the saline solution to ensure a thin and even spread on the slide. The smear was then allowed to air dry. Next, the slide was initially stained with ammonium oxalate crystal violet solution for 1 min, mordanted with Lugol's iodine solution for 1 min, destained with 95% ethanol solution for 30 s, and counterstained with safranin solution for 1 min. After rinsing with water, the slide was allowed to air dry until ready for instrumental analysis.

[0071] The test results showed that strain C11 was a Gram-negative bacterium.

[0072] 2) Scanning electron microscopy (SEM) observation of cell morphology: The isolated and purified PFOSA-degrading bacterial strain C11 was inoculated into LB medium and cultured at 30℃ and 150 rpm until the logarithmic growth phase. 2 mL of culture medium was taken and washed 2-3 times with 1×PBS for 15 min each time, followed by centrifugation at 5000 rpm for 3 min. The supernatant was removed. The bacterial pellet was resuspended in 1 mL of 2.5% glutaraldehyde solution and fixed overnight at 4℃. The sample was then washed 2-3 times with 1×PBS for 15 min each time, followed by centrifugation at 5000 rpm for 3 min. The supernatant was removed. The sample was then dehydrated with a gradient of 10%, 30%, 50%, 70%, 90%, and 100% ethanol solutions. Acetone was added to convert the ethanol to 100% three times. Finally, fresh acetone was added, and the sample was air-dried until ready for SEM observation of cell surface morphology. The SEM results of strain C11 are shown below. Figure 12 As shown.

[0073] Depend on Figure 12 As observed by scanning electron microscopy, strain C11 is rod-shaped, without flagella, and the cell size is approximately 0.5 μm × 2 μm.

[0074] 3) Physiological and biochemical characteristics of strain C11 (1) Oxidase test: The isolated and purified PFOSA degrading bacteria strain C11 was inoculated on LB solid medium. After the bacteria grew on the plate, a single colony was picked up with a fine glass rod and smeared on an oxidase test paper moistened with deionized water. If it turned blue-purple within 30s, it was positive; if it did not change color within 2min, it was negative.

[0075] (2) Contact enzyme test: The isolated and purified PFOSA-degrading bacterial strain C11 was inoculated on LB solid medium. After the bacteria grew on the plate, a single colony was taken for the experiment. First, 1 mL of 3% hydrogen peroxide solution was added to a clean glass slide. Then, a single colony was picked up into the solution using an inoculation loop. The presence of bubbles on the glass slide indicated a positive result, while the absence of bubbles indicated a negative result.

[0076] (3) Starch hydrolysis test: The isolated and purified PFOSA-degrading bacterial strain C11 was inoculated onto a starch solid medium. After the colonies grew on the plate, iodine solution was added to the starch solid medium and spread evenly. The appearance of colorless transparent aldehyde around the colonies indicates a positive result, while the surrounding area remains blue-black, indicating a negative result.

[0077] (4) Methyl red test: The isolated and purified PFOSA-degrading bacterial strain C11 was inoculated into methyl red medium and cultured at room temperature for 3 days. 2 mL of the culture medium was placed in a test tube, and 0.5 mL of methyl red reagent was added. After thoroughly mixing the culture medium and reagent, the color change was observed. A red or orange color indicates a positive result, while a yellow color indicates a negative result.

[0078] (5) VP test: The isolated and purified PFOSA-degrading bacterial strain C11 was inoculated into VP medium and cultured at room temperature for 4 days. 2 mL of culture medium was placed in a test tube, and solutions A and B were added according to the VP kit instructions. After thorough mixing of the culture medium and reagents, the mixture was allowed to stand for 2 hours to observe the color change. A red color indicates a positive result, while no color change indicates a negative result.

[0079] (6) Nitrate Reduction Test: The isolated and purified PFOSA-degrading bacterial strain C11 was inoculated into nitrate medium and cultured at room temperature for 5 days. 2 mL of the culture medium was placed in a test tube, and solutions A and B were added according to the nitrate reduction kit instructions. After thorough mixing of the culture medium and reagents, the mixture was allowed to stand for 5 minutes to observe the color change. A red color indicates a positive result, while no color change indicates a negative result.

[0080] (7) Hydrogen sulfide test: The isolated and purified PFOSA-degrading bacteria are inoculated on nitrate solid medium. After the bacteria have grown on the plate, a single colony is picked up with an inoculation needle and streaked in a zigzag pattern into a hydrogen sulfide ampoule. The ampoule is incubated for 2 days. If the color turns black, the test is positive; if the color does not change, the test is negative.

[0081] The results of the physiological and biochemical performance tests of strain C11 are shown in Table 3. Table 3 Results of physiological and biochemical performance determination of strain C11

[0082] Note: "+" indicates a positive result; "-" indicates a negative result.

[0083] Table 3 shows that strain C11 is a Gram-negative bacterium, and the results of oxidase, catalase, VP, and nitrate reduction tests were all positive; the results of amylase, methyl red, and hydrogen sulfide tests were all negative. Combined with the physiological and biochemical test results of strain C11 in Bergey's Manual of Bacterial Identification and the Manual of Systematic Identification of Common Bacteria, this strain conforms to the characteristics of *Trichophyton mentagrophytes*. The physiological and biochemical performance test results are consistent with the morphological observation results; further molecular biological identification and analysis are needed for further verification.

[0084] 4) Molecular identification After extensive screening and comprehensive consideration, selected strains were identified and further studied. Strain C11 was inoculated into LB medium and cultured at 30°C and 150 rpm for 24 hours with shaking. Total DNA was extracted from the strain using a bacterial total DNA extraction kit and sent to a biotechnology company for sequencing. The obtained strain sequences were then subjected to BLAST sequence alignment analysis in the NCBI database to construct a phylogenetic tree. Figure 1 As shown.

[0085] Sequencing results showed that strain C11 was *Trichomonas testis*. Comamonas testosteroni Its 16S rRNA sequence is shown in SEQ ID NO:1; and the *Trichomonas testis* ( Comamonas testosteroni Strain C11 was deposited at the China Center for Type Culture Collection on March 6, 2023, with accession number CCTCC NO: M 2023247.

[0086] Example 3 Effect of strain C11 on PHOSA degradation performance (1) Preparation of bacterial culture and seed culture The preparation method of bacterial suspension of strain C11 is as follows: the screened degrading strain is inoculated into a 100mL Erlenmeyer flask containing 50mL LB medium, and cultured with shaking at 30℃ and 150r / min until the logarithmic growth phase, and the OD of the bacterial suspension is obtained. 600 It is 0.8.

[0087] The bacterial suspension was prepared as follows: The bacterial cultured to the logarithmic growth phase was centrifuged at 8000 rpm for 5 minutes, the supernatant was removed, and the bacterial cells were collected. The bacterial cells were washed with an appropriate amount of 1×PBS, centrifuged at 8000 rpm for 5 minutes, and the supernatant was removed. This process was repeated three times. Finally, an appropriate amount of 1×PBS was added to resuspend the bacterial cells in OD200. 600 A bacterial suspension with a value of around 1.0 was used as the seed culture.

[0088] (2) Effect of different pH values ​​on the PFOSA degradation performance of strain C11 To determine the optimal pH for PFOSA degradation by strain C11, five different pH values ​​were selected: 5.0, 6.0, 7.0, 8.0, and 9.0. The pH of the inorganic salt medium was adjusted using 1 mol / L HCl and 1 mol / L NaOH. After autoclaving, an appropriate amount of PFOSA stock solution was added to achieve a concentration of 20 mg / L. Inorganic salt media with different pH values ​​and PFOSA as the sole carbon source were thus obtained, with an initial PFOSA concentration of 20 mg / L.

[0089] Seed culture was inoculated into inorganic salt media with different pH values ​​and PFOSA as the sole carbon source. The uninoculated degrading strain C11 served as a blank control. Each experiment was repeated three times. The culture was incubated with shaking at 150 rpm for 14 days. Samples were taken at 1, 3, 5, 7, 9, 11, 13, and 14 days after inoculation to determine the OD value of strain C11. 600 And the concentration of the remaining PFOSA.

[0090] OD of strain C11 cultured for 14 days under different pH conditions 600 The degradation rate of PFOSA by strain C11 is shown in Table 4. The OD values ​​of strain C11 under different pH conditions are also shown. 600 like Figure 2 As shown; the degradation rate of PFOSA by strain C11 under different pH conditions is as follows: Figure 3 As shown.

[0091] Table 4. OD values ​​of strain C11 after 14 days of culture under different pH conditions. 600 and the degradation rate of PFOSA

[0092] From Table 4 and Figure 2 , Figure 3 It was found that strain C11 grew well within the pH range used in the experiment, with the optimal growth pH range being 5.0–9.0. Regarding PFOSA degradation, within the pH range of 6.0–8.0, the degradation effect of strain C11 on PFOSA increased with increasing OD value. 600 The degradation rate of PFOSA increased with the growth of bacteria; within the optimal growth pH range, strain C11 exhibited the highest degradation rate (55.5%) at pH 7.0; as the pH continued to rise to 9.0, the PFOSA degradation rate gradually decreased. Therefore, subsequent experimental strains were cultured at pH 7.0.

[0093] (3) Effect of different temperatures on the PFOSA degradation performance of strain C11 To determine the optimal temperature for PFOSA degradation by strain C11, five different culture temperatures were selected: 20℃, 25℃, 30℃, 35℃, and 40℃. The pH of the inorganic salt medium was adjusted to 7.0, and after high-temperature sterilization, an appropriate amount of PFOSA stock solution was added to achieve a concentration of 20 mg / L. This yielded an inorganic salt medium with PFOSA as the sole carbon source, with an initial PFOSA concentration of 20 mg / L.

[0094] Seed culture was inoculated into inorganic salt medium with PFOSA as the sole carbon source. A control group without inoculation of degrading bacteria was used. Each experiment was repeated three times. After inoculation, the culture system was incubated for 14 days in shakers at 20℃, 25℃, 30℃, 35℃, and 40℃ at 150 r / min. Samples were taken at 1, 3, 5, 7, 9, 11, 13, and 14 days after inoculation to determine the OD of strain C11. 600 And the concentration of the remaining PFOSA.

[0095] OD of strain C11 cultured for 14 days under different temperature conditions 600 The degradation rate of PFOSA by strain C11 is shown in Table 5. The OD values ​​of strain C11 under different temperature conditions are also shown. 600 like Figure 4 As shown; the degradation rate of PFOSA by strain C11 under different temperature conditions is as follows: Figure 5 As shown.

[0096] Table 5. OD values ​​of strain C11 cultured for 14 days under different temperature conditions. 600 and the degradation rate of PFOSA

[0097] From Table 5 and Figure 4 , Figure 5 It was found that strain C11 grew well within the temperature range used in the experiment, with the optimal growth temperature being 20℃~35℃. Regarding the PFOSA degradation effect, within the range of 20℃~30℃, the PFOSA degradation rate of strain C11 increased with increasing OD of the strain. 600 The growth rate increased with increasing temperature. Within the optimal growth temperature range, strain C11 showed the best PFOSA degradation effect at 30℃, with a degradation rate of 55.5%. When the temperature was further increased to 40℃, the PFOSA degradation rate was only 5.65%, indicating that excessively high temperatures lead to denaturation of intracellular enzyme proteins, resulting in enzyme inactivation. This not only affects the growth of the strain but also the PFOSA degradation rate. Therefore, subsequent experiments were conducted at 30℃.

[0098] (4) Effect of initial PFOSA concentration on PFOSA degradation performance Five different initial PFOSA concentrations were selected: 10 mg / L, 20 mg / L, 30 mg / L, 40 mg / L, and 50 mg / L. The pH of the inorganic salt medium was adjusted to 7.0, and after autoclaving, an appropriate amount of PFOSA stock solution was added. Inorganic salt media with PFOSA as the sole carbon source and initial PFOSA concentrations of 10 mg / L, 20 mg / L, 30 mg / L, 40 mg / L, and 50 mg / L were thus obtained.

[0099] Seed culture was inoculated into inorganic salt medium with PFOSA as the sole carbon source. A control group without inoculation of degrading bacteria was used. Each experiment was repeated three times. After inoculation, the culture system was incubated at 30℃ and 150 rpm with shaking for 14 days. Samples were taken at 1, 3, 5, 7, 9, 11, 13, and 14 days after inoculation to determine the OD of strain C11. 600 And the concentration of the remaining PFOSA.

[0100] OD of strain C11 cultured for 14 days under different initial PFOSA concentrations 600 The degradation rate of PFOSA by strain C11 is shown in Table 6. The OD values ​​of strain C11 under different initial PFOSA concentrations are also shown. 600 like Figure 6 As shown; the degradation rate of PFOSA by strain C11 under different initial PFOSA concentrations is as follows: Figure 7 As shown.

[0101] Table 6. OD values ​​of strain C11 after 14 days of culture under different initial PFOSA concentrations. 600 and the degradation rate of PFOSA

[0102] From Table 6 and Figure 6 , Figure 7 It can be seen that within the initial concentration range of PHOSA (10-30 mg / L), OD 600 The OD value increases with increasing concentration, and the degradation rate of PFOSA also increases. At an initial concentration of 30 mg / L, the OD value... 600 The strain reached a maximum value of 1.382, and also achieved an optimal degradation rate of 64.6% for PFOSA. When the initial PFOSA concentration exceeded 30 mg / L, the OD... 600 The PFOSA concentration decreased with increasing concentration, and the degradation efficiency of strain C11 also decreased with increasing initial PFOSA concentration. This may be because excessively high initial PFOSA concentrations have toxic side effects on strain C11, disrupting its cellular physiological functions. Therefore, subsequent experimental strain cultures were cultured with an initial PFOSA concentration of 30 mg / L.

[0103] Example 4 Degradation characteristics of strain C11 (1) PHOSA detection method a. Sample pretreatment: Take 1 mL of culture medium that has been degraded for a certain period of time, dilute it to 10 mL, and purify it by passing it through a PWAX-SPE column. Install the solid-phase extraction column onto the solid-phase extraction device, and activate it sequentially with 4 mL of 0.1% ammonia-methanol solution, 4 mL of methanol, and 4 mL of pure water. Pass the sample through the activated solid-phase extraction column at a flow rate controlled at 1 drop / s, and then rinse with 4 mL of 25 mmol / L ammonium acetate aqueous solution to remove impurities. After drying the SPE column with a nitrogen blower, elute the target contaminant with 4 mL of methanol and 4 mL of 0.1% ammonia-methanol solution. Collect the eluent and blow it into powder with nitrogen gas. Make up the volume with 10 mL of methanol, then pass it through a 0.22 μm organic filter membrane. Transfer 1 mL to a brown sample vial and store at 4 °C until ready for instrumentation.

[0104] b. Quantitative analysis was performed using a triple quadrupole LC-MS / MS. The analytical conditions were as follows: the column was an Agilent Poroshell 120 EC-C18 (3.0 × 150 mm, 2.7 μm); the mobile phase was methanol (A) and 2.5 mmol / L ammonium acetate aqueous solution + 0.1% formic acid (B); the gradient elution ratios are shown in Table 7. The column temperature was 50 °C, the injection volume was 10 μL, and the flow rate was 0.4 mL / min.

[0105] Table 7 Mobile phase elution ratios for triple quadrupole liquid chromatography-mass spectrometry (LC-MS)

[0106] c. Establishment of the standard curve: Six samples of PFOSA stock solution were prepared at concentrations of 0.2 mg / L, 0.5 mg / L, 1 mg / L, 2 mg / L, 3 mg / L, and 5 mg / L. 1.5 mL of each sample was placed in a brown chromatographic vial and analyzed using a triple quadrupole LC-MS / MS. The standard curve of PFOSA concentration was obtained by fitting the curve with PFOSA concentration as the x-axis and the peak area obtained by integration as the y-axis. Figure 8 As shown.

[0107] The formula for the PFOSA standard curve is: A c =a+bc Where c represents the concentration of PFOSA (mg / L), A c This represents the peak area corresponding to a PHOSOSA concentration of c. The value of a is 254.42, and the value of b is 182.05. R 2 It is 0.9990.

[0108] (2) Strain C11 was inoculated into an inorganic salt medium with PFOSA as the sole carbon source. The initial concentration of PFOSA in the inorganic salt medium with PFOSA as the sole carbon source was 30 mg / L, and the inoculation amount was 2% of the medium volume. The OD of the inoculated bacterial suspension was... 600 The culture was carried out at 30℃ and 150 r / min for 14 days with shaking. A blank control group without inoculation of degrading bacteria was used, and each group was tested in triplicate.

[0109] Samples were taken at 1, 3, 5, 7, 9, 11, 13 and 14 days after inoculation to determine the bacterial concentration, the PFOSA concentration in the culture medium and calculate the degradation rate.

[0110] The changes in bacterial concentration and the PFOSA degradation rate at 1, 3, 5, 7, 9, 11, 13, and 14 days after inoculation are detailed in Table 8. The changes in bacterial concentration at 1, 3, 5, 7, 9, 11, 13, and 14 days after inoculation are shown in Table 8. Figure 9 As shown; the degradation rate of PFOSA at 1d, 3d, 5d, 7d, 9d, 11d, 13d and 14d after inoculation is as follows: Figure 10 As shown.

[0111] Table 8 shows the changes in bacterial concentration and PFOSA degradation rate at 1, 3, 5, 7, 9, 11, 13, and 14 days after inoculation.

[0112] From Table 8 and Figure 9 , Figure 10 It can be seen that the strain reached the logarithmic growth phase 3 days after inoculation and gradually entered the stationary phase after 5 days. The degradation of PFOSA by strain C11 accompanied the entire growth process of the strain, and by 14 days, it could degrade 64.6% of PFOSA.

[0113] In summary, the *Trichomonas testis* C11 provided by this invention can efficiently degrade PFOSA, with a degradation rate as high as 64.6%. The discovery of *Trichomonas testis* C11 provides a strain resource for the efficient biodegradation of PFOSA and lays the foundation for the application of this strain in the purification of PFAS-contaminated environments.

[0114] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A strain of *Trichomonas testis* ( Comamonas testosteroni C11, characterized in that, The preservation number of *Trichomonas testis* C11 is CCTCC NO: M 2023247.

2. A perfluorooctane sulfonamide-degrading bacterial solution, characterized in that, Includes *Trichomonas vaginalis* C11 as described in claim 1.

3. The method for preparing the bacterial solution according to claim 2, characterized in that, Includes the following steps: The *Trichomonas vaginalis* C11 was cultured in a culture medium to obtain a bacterial solution.

4. The preparation method according to claim 3, characterized in that, The culture temperature is 20℃~35℃.

5. A method for degrading perfluorooctane sulfonamides using *Trichophyton mentagrophytes* C11 as described in claim 1, the bacterial solution as described in claim 2, or the bacterial solution prepared by the method described in claim 3 or 4, characterized in that... include: Testosterone-bearing Trichomonas citrate C11 or its bacterial culture was mixed with perfluorooctane sulfonamide to degrade perfluorooctane sulfonamide.

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