A strain of streptomyces sp. M-1 for degrading polycyclic aromatic hydrocarbons

Abstract

A highly efficient polycyclic aromatic hydrocarbon (PAH) degrading bacterium belonging to the genus *Streptomyces* sp., with accession number CCTCC M 2024204, was isolated from contaminated kerosene. This strain, *Streptomyces sp. M-1*, exhibits remarkable degradation efficiency for anthracene in PAHs, showing the best growth rate at an anthracene concentration of 100 mg·L⁻¹. ‑1 At that time, Streptomyces sp. M-1 showed the highest 7-day degradation rate of anthracene, reaching 93.14%, with a maximum average degradation rate of 2.720 mg / day. ‑1 At an anthracene / phenanthrene concentration of 50 mg·L⁻¹ ‑1 After 14 days of cultivation, the degradation rate of anthracene in the actual water body was 98.98%, and the degradation rate of phenanthrene was 72.77%.

Description

Technical Field

[0001] This invention relates to the biological treatment of environmental pollutants, specifically to a highly efficient polycyclic aromatic hydrocarbon degrading strain of Streptomyces sp. M-1 and its application patent application. Background Technology

[0002] Polycyclic aromatic hydrocarbons (PAHs) are persistent and toxic organic chemical pollutants composed of two or more benzene rings. They exhibit "three-fold" effects: mutagenicity, carcinogenicity, and teratogenicity. PAHs can be formed from hydrocarbon-containing compounds produced by the incomplete combustion or pyrolysis of various fossil fuels and wood, and are widely distributed in different environmental media. Low-ring aromatic hydrocarbons are more easily transferred from soil to wheat, and PAHs in soil and water eventually enter the human body through the food chain. Once in the human body, the metabolites of PAHs bind to biological macromolecules such as DNA and proteins, potentially leading to DNA mutations. Many carcinogenic, immune, and reproductive diseases are associated with PAH exposure, posing a serious threat to human health and ecological security.

[0003] PAH-contaminated water bodies and soils can be remediated using physical, chemical, and biological methods. Physical remediation methods are costly and unsuitable for large-scale soil and water remediation. Chemical remediation, with long-term use, alters the original soil structure and physicochemical properties, negatively impacting biological growth. Bioremediation, on the other hand, is an environmentally friendly technology that does not cause secondary pollution. It is highly efficient, clean, and inexpensive, making it the primary approach to resolving PAH pollution.

[0004] Currently known microorganisms capable of degrading PAHs include algae, fungi, and bacteria. Bacteria are the most widely studied group, characterized by rapid and simple reproduction, strong metabolic capacity, and diverse metabolic pathways. They are relatively safe for plants during microbial remediation of PAHs in soil (the vast majority of plant diseases are caused by pathogenic fungi). These include Bacillus, Pseudomonas, Rhodococcus, Sphingospora, Flavobacterium, Mycobacterium, Klebsiella, and Trichoderma. However, research on PAH-degrading bacteria is largely limited to laboratory conditions, lacking validation in actual polluted water bodies. Furthermore, the application of PAH-degrading bacteria in actual contaminated sites is often constrained by environmental conditions and other factors. Therefore, screening for environmentally adaptable, highly efficient, and stable PAH-degrading bacteria is a crucial prerequisite for bioremediation. Summary of the Invention

[0005] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a highly efficient polycyclic aromatic hydrocarbon (PAH) degrading bacterium and its application, which is used to solve the problem of strain environmental adaptability, thereby meeting the technical needs of PAH degradation and water remediation under relevant environmental conditions.

[0006] The technical solution adopted in this invention is described in detail below.

[0007] The first objective of this invention is to provide a polycyclic aromatic hydrocarbon degrading strain of the genus Streptomyces p. M-1. This strain belongs to the genus Streptomyces. After preliminary identification, the strain was named Streptomyces sp. M-1, and its accession number is CCTCC M 2024204. It was deposited on January 25, 2024, at the China Center for Type Culture Collection (CCTCC) located at Wuhan University, China.

[0008] The degrading bacterium Streptomyces sp. M-1 provided by this invention was isolated from contaminated oil samples. No studies on the degradation of polycyclic aromatic hydrocarbons (PAHs) anthracene by this strain have been reported domestically or internationally. After being cultured on tryptic soybean agar (TSA) plates at 35°C for 2-3 days, the colonies of this strain were milky white, small and dense, opaque, with regular edges, smooth surfaces, and were not easily picked up.

[0009] The morphological characteristics of the Streptomyces sp. M-1 strain provided by this invention are: Gram-positive, rough cell surface, no flagella, and no spores.

[0010] The physiological and biochemical characteristics of the Streptomyces sp. M-1 strain provided by this invention are as follows: positive for β-galactosidase production, citric acid utilization, arginine dihydrolase, lysine decarboxylase, ornithine decarboxylase, H2S production, and urease; negative for gelatin hydrolysis, oxidase, VP, and indole production.

[0011] The 16S rDNA gene sequence characteristics of Streptomyces sp.M-1 provided by this invention are shown in the sequence listing.

[0012] The screening process for Streptomyces sp. M-1 provided by this invention includes the following steps:

[0013] (1) Enrichment: In order to maximize the selection of target bacteria, enrichment was carried out twice in TSB medium to obtain enriched mixed bacteria.

[0014] (2) Initial screening: The enriched mixed bacteria were transferred to a selective liquid culture medium with kerosene as the sole nutrient source and incubated at 35°C and 165 rpm.

[0015] The microbial community was cultured under the same conditions until it became turbid, and then transferred three times under the same conditions to finally obtain a microbial community that could utilize the kerosene mixture.

[0016] (3) Isolation: Under aseptic conditions, use a pipette to aspirate the initially screened culture medium, dilute it serially with sterile water, and spread it onto a selective solid medium. Incubate at 35°C for an appropriate time. After colonies have grown on the plates, select colonies with good growth and different morphologies.

[0017] (4) Purification: The obtained colonies are separated by streak plating multiple times until a single strain is obtained.

[0018] (5) Secondary screening: The purified single strain was inoculated into a selective liquid culture medium with kerosene as the sole nutrient source and cultured at 35°C and 165 rpm for 7 days. The kerosene content in the culture medium was measured, the degradation rate was calculated, and the degrading strain Streptomyces sp.M-1 was obtained by screening based on the degradation rate.

[0019] A second objective of this invention is to provide the Streptomyces sp. M-1 for degrading polycyclic aromatic hydrocarbon pollutants, specifically anthracene or phenanthrene within polycyclic aromatic hydrocarbons.

[0020] The Streptomyces M-1 strain obtained in this application exhibits good degradation activity against polycyclic aromatic hydrocarbons (PAHs) such as anthracene, at an anthracene concentration of 100 mg·L⁻¹. -1 At that time, Streptomyces sp. M-1 showed the highest 7-day degradation rate of anthracene, reaching 93.14%, with a maximum average degradation rate of 2.720 mg / day. -1 .

[0021] A third objective of this invention is to provide the application of the aforementioned Streptomyces sp. M-1 in the degradation of polycyclic aromatic hydrocarbon pollutants, characterized in that the degradation of anthracene or phenanthrene is carried out under laboratory conditions and actual polluted water conditions, respectively.

[0022] A fourth objective of this invention is to provide the application of the aforementioned Streptomyces sp. M-1 in the bioremediation of polycyclic aromatic hydrocarbon-contaminated water bodies.

[0023] This invention domesticated and isolated a strain M-1 capable of degrading anthracene and phenanthrene from contaminated oil samples. Based on the strain's morphology, physiological characteristics, Gram reaction, 16S rDNA gene sequencing analysis, and phylogenetic analysis, the strain was identified as Streptomycess p. This strain can utilize anthracene or phenanthrene as the sole carbon source and rapidly degrade anthracene; at an initial anthracene concentration of 200 mg·L⁻¹, it can degrade anthracene rapidly. -1After culturing in an inorganic salt medium for 4 days, the degradation rate was 81.66%. When the bacterium was inoculated into inorganic salt media with different anthracene concentrations, the maximum average degradation rate of anthracene by Streptomyces sp. M-1 was 2.720 mg / dL. -1 Streptomyces sp. M-1 showed good degradation effects on anthracene / phenanthrene in actual organisms. After 14 days of cultivation, the degradation rate of anthracene in actual water bodies was 98.98%, almost completely degraded, while the degradation rate of phenanthrene in actual water bodies was 72.77%. Therefore, this strain has good application potential in bioremediation. Attached Figure Description

[0024] Figure 1 (a) Ultraviolet spectrum analysis of aviation kerosene solution; (b) Standard curve of aviation kerosene concentration-absorbance.

[0025] Figure 210 shows the degradation rate of aviation kerosene by the bacteria.

[0026] Figure 3 (a) Colony morphology of M-1; (b) SEM image of M-1.

[0027] Figure 4 Phylogenetic tree of strain M-1

[0028] Figure 5 Growth curve of Streptomyces sp. M-1

[0029] Figure 6 (a) UV spectrum of anthracene standard solution; (b) UV spectrum of phenanthrene standard solution.

[0030] Figure 7 (a) Anthracene concentration-absorbance standard curve; (b) Phenanthrene concentration-absorbance standard curve

[0031] Figure 8 (a) Degradation of anthracene by Streptomyces sp. M-1; (b) Effect of anthracene concentration on the anthracene degradation performance of Streptomyces sp. M-1.

[0032] Figure 9 (a) The degradation effect of Streptomyces sp. M-1 on phenanthrene; (b) The effect of phenanthrene concentration on the phenanthrene degradation performance of Streptomyces sp. M-1.

[0033] Figure 10 (a) Degradation of anthracene by Streptomyces sp. M-1 in real water bodies; (b) Degradation of phenanthrene by Streptomyces sp. M-1 in real water bodies. Detailed Implementation

[0034] Example 1: Screening of highly efficient polycyclic aromatic hydrocarbon degrading bacteria

[0035] Enrichment medium: tryptic soy broth.

[0036] Selective liquid culture medium: kerosene 0.7 mL, MgSO4 1.0 g, K2HPO4 0.5 g, KH2PO4 0.5 g, Na2SO4 1.0 g, CaCl2 0.1 g, NaCl 30 g, (NH4)2SO4 2.5 g, yeast extract 0.1 g, sodium lactate aqueous solution (1.270–1.330 g / mL) -1 1.0 mL, 1000 mL distilled water.

[0037] Selective solid culture medium: kerosene 0.7 mL, MgSO4 1.0 g, K2HPO4 0.5 g, KH2PO4 0.5 g, Na2SO4 1.0 g, CaCl2 0.1 g, NaCl 30 g, (NH4)2SO4 2.5 g, yeast extract 0.1 g, sodium lactate aqueous solution (1.270–1.330 g / mL) -1 1.0 mL, 18 g agar powder, 1000 mL distilled water.

[0038] Tryptic soybean peptone liquid medium (TSB): 17.0 g tryptic peptone, 3.0 g plant peptone, 2.5 g K2HPO4·3H2O, 5.0 g NaCl, 2.5 g glucose, 1000 mL distilled water, pH 7.0±0.2.

[0039] Under aseptic conditions, the bacteria in the contaminated oil sample were filtered onto a sterile filter membrane, rinsed with sterile water to obtain a bacterial suspension, inoculated into an enrichment medium, and cultured at 35°C and 165 rpm for 24-36 hours. Then, 2 mL of the enrichment culture was added to fresh enrichment medium and cultured under the same conditions for 24-36 hours to obtain the enriched mixed bacteria, thus completing the enrichment process.

[0040] Initial screening: The enriched mixed bacteria were transferred to a selective liquid culture medium with kerosene as the sole nutrient source and cultured at 35°C and 165 rpm until turbidity was observed. The same conditions were repeated 3 times to finally obtain a microbial community that could utilize the kerosene mixture.

[0041] Isolation: Under aseptic conditions, use a pipette to aspirate the initially screened culture medium, serially dilute it with sterile water, and spread it onto selective solid culture medium. Incubate at 35°C for an appropriate time. After colonies have grown on the plates, select colonies that are in good growth condition and have different morphologies.

[0042] Purification: The obtained colonies are isolated by repeated streak plating until a single strain is obtained.

[0043] Secondary screening: The purified single strain was inoculated into a selective liquid culture medium with kerosene as the sole nutrient source and cultured at 35℃ and 165 rpm for 7 days. The kerosene content in the culture medium was measured, and the degradation rate was calculated. Based on the degradation rate, the degrading bacterium Streptomyces sp. M-1 was screened. The specific measurement method is as follows:

[0044] (1) Establish a method for determining kerosene content by ultraviolet spectrophotometry

[0045] First, the optimal absorption wavelength was determined. Petroleum ether (60–90℃) was used as the extractant to extract kerosene added to the liquid screening medium. 10.0 mL of petroleum ether was added each time, and the mixture was allowed to stand for 10 min in a separatory funnel. After separation, the petroleum ether layer was collected. This process was repeated three times. The collected petroleum ether mixture was diluted to an appropriate concentration and then subjected to a full-wavelength UV scan. Simultaneously, a 1.0 g·L⁻¹ solution was prepared… -1 A kerosene standard solution was prepared, with petroleum ether as a blank control. The extracted solution and 1.0 g·L⁻¹ were analyzed using a UV-Vis spectrophotometer in the wavelength range of 200–300 nm. -1 The absorbance of the kerosene standard solution was measured to determine the optimal absorption wavelength as 266 nm (see Appendix). Figure 1 a) Next, plot the standard curve. Prepare a concentration of 100–1000 mg·L⁻¹. -1 A standard solution of kerosene was prepared, with petroleum ether as a blank control. The absorbance at 266 nm was measured using a UV-Vis spectrophotometer. A standard curve was plotted with the mass concentration of kerosene on the x-axis and absorbance on the y-axis (see Appendix). Figure 1 b). Next, perform a spiked recovery experiment. Accurately pipette a 0.7 mg / mL solution. -1 1.0 mL of the sample was placed in a small beaker, and 1.0 mL of solutions with concentrations of 0.7, 0.9, and 1.1 mg / mL were added respectively. -1 The absorbance of the kerosene standard solution was determined according to the method established above, and the spiked recovery rate was calculated (see Table 1). Finally, an accuracy experiment was performed. 0.7 g·L⁻¹ of kerosene standard solution was pipetted... -1 The standard solution of kerosene was prepared in 6 small test tubes, and its absorbance was measured according to the method established above. The accuracy was then calculated.

[0046] (2) Determination of kerosene content in culture medium

[0047] The degrading bacteria were inoculated into TSB medium and activated at 35°C and 165 rpm for 12 h. The activated culture was then transferred to liquid screening medium at an inoculation rate of 2% (v / v) and incubated at 35°C and 165 rpm for 7 days. Each group had three replicates, with a blank medium as a control. Petroleum ether was used as the extraction solvent, with 10.0 mL added each time. After shaking, the mixture was allowed to stand for 10 min in a separatory funnel. After separation, the petroleum ether layer was collected, and the extraction was repeated three times. The concentration of kerosene was determined using a UV-Vis spectrophotometer after extraction. The residual amount of kerosene was calculated using a standard curve, and the degradation rate was calculated using the following formula:

[0048]

[0049] In the formula, c1 represents the kerosene concentration of the blank sample, in mg·L⁻¹. -1 ;

[0050] c2 — Residual kerosene concentration in the culture medium, mg·L⁻¹ -1 ;

[0051] V1 — Volume of culture medium, L;

[0052] V2 — Volume after petroleum ether extraction, in L.

[0053] Using kerosene degradation rate as the evaluation index, Streptomyces sp. M-1 was finally selected, with a degradation efficiency of almost 100% (see appendix). Figure 2 ).

[0054] Example 2: Identification of the Streptomyces sp. M-1 strain provided by the present invention

[0055] The Streptomyces sp. M-1 provided by this invention was isolated from a contaminated oil sample and purified by repeated dilutions and plate coating. It was then identified through morphological observation, physiological and biochemical reactions, and genetic testing.

[0056] Streptomyces sp. M-1 can grow single colonies on TSA plates at 35°C for 48–72 hours. These single colonies are milky white, small, dense, opaque, with regular edges, smooth surfaces, and are not easily picked up (see attached image). Figure 3 a) This strain is Gram-positive, has a rough cell surface, no flagella, and no spores (see appendix). Figure 3 b);

[0057] The results for β-galactosidase production, citrate utilization, arginine dihydrolase, lysine decarboxylase, ornithine decarboxylase, H2S production, and urease were positive, while the results for gelatin hydrolysis, oxidase, VP, and indole production were negative (see Table 2).

[0058] Genomic DNA was extracted from *Streptomyces* sp. M-1 using a bacterial genomic DNA extraction kit (Tiangen Biotech Co., Ltd.). PCR amplification was performed using the upstream primer 5'-AGAGTTTGATCCTGGCTCAG-3' and the downstream primer 5'-GGTTACCTTGTTACGACTT-3' to obtain the 16S rDNA gene fragment. The amplified product was sent to the Qingdao branch of Beijing Qingke Biotechnology Co., Ltd. for sequencing. Homologous sequences were analyzed using BLAST on the NCBI website. A phylogenetic tree of the strain was constructed using MEGA 7.0 software and ClustalX 2.0. Sequencing results showed that the 16S rDNA gene sequence of this strain was 1429 bp in length. Sequencing and alignment of the 16S rDNA sequence (the sequenced result showed the highest similarity (99.72%) to the sequence accession number OR186246.1 in GenBank) led to the construction of a phylogenetic tree (see Appendix). Figure 4 Based on the results, it can be preliminarily determined that this strain belongs to the genus Streptomyces and is named Streptomyces sp.M-1.

[0059] Example 3: Preparation of Seed Liquid

[0060] The Streptomyces sp. M-1 strain was inoculated into a 250 mL Erlenmeyer flask containing 50 mL of TSB liquid medium and cultured at 35°C for 76 hours on a shaker at 165 rpm to obtain the seed culture.

[0061] Example 4: Degradation of anthracene and phenanthrene by degrading bacteria under experimental conditions

[0062] (1) Growth curve determination

[0063] Based on the mycelial dry reconstitution of the strain, a cell growth curve was plotted, and the OD was measured every 4 hours using a UV spectrophotometer. 600 The absorbance value at nm was used to determine that 76 hours was the optimal inoculation time for the bacterial strain (see Appendix). Figure 5 ).

[0064] (2) Establish a method for determining the content of anthracene and phenanthrene by ultraviolet spectrophotometry.

[0065] First, determine the optimal absorption wavelength. Prepare a 15 mg·L⁻¹ solution using cyclohexane as the solvent. -1 anthracene standard solution and 5 mg·L -1Using phenanthrene standard solutions and cyclohexane as a blank control, the absorbance of anthracene and phenanthrene standard solutions was measured using a UV-Vis spectrophotometer in the wavelength range of 200–400 nm. The optimal absorption wavelength was determined to be 355 nm for anthracene (see Appendix). Figure 6 a) The method for determining the optimal absorption wavelength (291 nm) of phenanthrene is the same as that for anthracene (see Appendix). Figure 6 b); Next, plot the standard curve. Prepare a concentration of 3–15 mg·L⁻¹. -1 Anthracene standard solution, 1–20 mg / L -1 Anthracene standard solution was used, with cyclohexane as a blank control. The absorbance at 355 nm (anthracene) / 291 nm (phenanthrene) was measured using a UV-Vis spectrophotometer. A standard curve was plotted with the mass concentration of anthracene / phenanthrene on the x-axis and absorbance on the y-axis (see Appendix). Figure 7 a, 7b); Next, conduct a spiked recovery experiment. ③ Accurately pipette a known concentration (10 mg·L⁻¹) -1 1.0 mL of the sample was placed in a small beaker, and 1.0 mL of each of the following concentrations (10, 20, and 30 mg·L⁻¹) was added respectively. -1 Anthracene and phenanthrene standard solutions were analyzed using the method established above, and their absorbance was determined. The recoveries were calculated (see Table 3). Finally, an accuracy experiment was performed. 5 mg·L⁻¹ of each standard solution was pipetted... -1 Anthracene, 15 mg·L -1 The absorbance of the phenanthrene standard solution in 6 small test tubes was measured according to the method established above, and the accuracy was calculated.

[0066] (3) Determination of anthracene and phenanthrene content

[0067] Cyclohexane was used as the extraction solvent. 20g of sodium chloride and 10mL of cyclohexane solution were added to 50mL of culture medium. The mixture was vortexed for 2 minutes, allowed to stand in a separatory funnel for 10 minutes, and after separation, the cyclohexane layer was collected. The extraction was repeated three times. After dehydration with anhydrous sodium sulfate, the solution was brought to a final volume of 30mL with cyclohexane. The degradation rate was determined by ultraviolet spectrophotometry. The concentrations of anthracene and phenanthrene were calculated using a standard curve. The degradation rates of anthracene and phenanthrene by Streptomyces sp. M-1 were calculated according to Formula 4-1.

[0068]

[0069] In the formula, c1 represents the anthracene / phenanthrene concentration of the blank sample, in mg·L⁻¹. -1 ;

[0070] c2 — Anthracene / phenanthrene residual concentration in the culture medium, mg·L⁻¹ -1 ;

[0071] V1 — Volume of culture medium, L;

[0072] V2 — Volume after cyclohexane extraction, in L.

[0073] The degradation effect of Streptomyces sp. M-1 on anthracene is shown in the attached figure. Figure 8 As shown in Figure a, the degradation effect of Streptomyces sp. M-1 on anthracene gradually increased with the extension of culture time, reaching its highest degradation rate of 81.66% on day 4 of culture. The effect of anthracene concentration on the anthracene degradation performance of Streptomyces sp. M-1 is shown in the attached figure. Figure 8 As shown in b, Streptomyces sp. M-1 also exhibits a certain degradation ability for higher concentrations of anthracene, at an anthracene concentration of 100 mg·L⁻¹. -1 At that time, Streptomyces sp. M-1 showed the highest degradation rate of anthracene, reaching 93.14%, and the maximum average degradation rate of anthracene by Streptomyces sp. M-1 was 2.720 mg / day. -1 .

[0074] The degradation effect of Streptomyces sp. M-1 on phenanthrene is shown in the attached figure. Figure 9 As shown in Figure a. The highest degradation rate of phenanthrene was observed on day 6 of cultivation, reaching 47.64%. The effect of phenanthrene concentration on the phenanthrene degradation performance of Streptomyces sp. M-1 is shown in the appendix. Figure 9 As shown in figure b, it can be seen that Streptomyces sp. M-1 also has a certain degradation ability for higher concentrations of phenanthrene, at a concentration of 50 mg·L⁻¹. -1 At that time, strain M-1 showed the highest degradation rate of phenanthrene at 49.26%, and the maximum average degradation rate of phenanthrene by Streptomyces sp. M-1 was 1.283 mg / d. -1 .

[0075] The results above show that the Streptomyces sp. M-1 strain has a better degradation and utilization effect on anthracene than phenanthrene, with an average degradation rate of anthracene that is about twice that of phenanthrene.

[0076] Example 5: Degradation of anthracene / phenanthrene by degrading bacteria in actual water bodies

[0077] Streptomyces sp. M-1 was activated and inoculated at 3% (v / v) into seawater culture medium containing anthracene / phenanthroline. The medium was cultured at 35°C and 165 rpm in a shaker. Samples were taken to determine the degradation rate of anthracene / phenanthroline in the culture medium. The experimental results are shown below. Figure 10As shown in the figure, Streptomyces sp. M-1 showed good degradation effect on anthracene / phenanthrene in actual organisms. After 14 days of cultivation, the degradation rate of anthracene in actual water was 98.98%, almost completely degraded, while the degradation rate of phenanthrene in actual water was 72.77%.

[0078] Table 1

[0079]

[0080] Table 2

[0081]

[0082] Note 1: "+" indicates a positive reaction, and "-" indicates a negative reaction.

[0083] Table 3

[0084]

Claims

1. A strain of Streptomyces M-1, a highly efficient polycyclic aromatic hydrocarbon degrading bacterium, characterized in that, This strain belongs to the genus Streptomyces sp. and is named Streptomyces sp. M-1. It is deposited at the China Center for Type Culture Collection (CCTCC) with accession number CCTCC No: M 2024204.

2. The application of the polycyclic aromatic hydrocarbon degrading strain Streptomyces M-1 according to claim 1 in the degradation of polycyclic aromatic hydrocarbon pollutants, characterized in that, The strain is used to degrade anthracene or phenanthrene in polycyclic aromatic hydrocarbons.

3. The application of the polycyclic aromatic hydrocarbon degrading strain Streptomyces M-1 as described in claim 2 in the degradation of polycyclic aromatic hydrocarbon pollutants, characterized in that, Under laboratory conditions, at an anthracene concentration of 100 mg·L⁻¹ -1 At that time, the strain exhibited the highest 7-day degradation rate of anthracene, reaching 93.14%, with a maximum average degradation rate of 2.720 mg / d. -1 .

4. The application of the polycyclic aromatic hydrocarbon (PAH) degrading strain *Streptomyces m-1* as described in claim 1 in the bioremediation of PAH-contaminated environments, characterized in that... The strain is used to degrade anthracene or phenanthrene in polycyclic aromatic hydrocarbons, wherein the degradation of anthracene or phenanthrene is carried out in water.

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