Paenibacillus WH-2 and its application

Abstract

The present invention discloses Paenibacillus contaminans WH-2 and its application, belonging to the field of microbial technology. The Latin name of Paenibacillus contaminans WH-2 is Paenibacillus contaminans WH-2, which is deposited in the General Microbiological Center of China Microbiological Culture Collection Administration Committee, with a deposit date of April 10, 2024, a deposit number of CGMCC No.30299, and a deposit address of Beijing, China. Paenibacillus WH-2 provided by the present invention is separated and screened from marine shellfish in the sea area contaminated by isopropyl metolachlor. The strain is adapted to a wide range of salinities, can efficiently degrade isopropyl metolachlor and 2-methyl-6-ethylaniline, and has an efficient bioremediation effect on the marine environment contaminated by isopropyl metolachlor and 2-methyl-6-ethylaniline.

Description

Technical Field

[0001] The invention relates to a marine bacterium and an application thereof, in particular to a Paenibacillus sp. WH-2 and an application thereof in degrading metolachlor and 2-methyl-6-ethylaniline (MEA), belonging to the technical field of microorganisms. Background Art

[0002] Isopropylamine is a chloroacetamide selective herbicide with a molecular formula of C 15 H 22 ClNO 2 Due to its broad spectrum, high efficiency and strong selectivity, isopropylamine is widely used in dryland crops, vegetable crops, orchards and rice transplanting fields.

[0003] 2-Methyl-6-ethylaniline (MEA) is an intermediate in the synthesis of chloroacetamides such as isopropylamine and acetochlor. It is also an important metabolite of the photolysis, hydrolysis and biodegradation of chloroacetamides. It can exist and accumulate in organisms for a long time in the natural environment, and is highly toxic, causing harm to organisms and human health.

[0004] Amide herbicides are frequently detected in the marine environment, indicating that their pollution has spread to the marine ecological environment.

[0005] The toxicity of amide herbicides to aquatic animals mainly manifests as teratogenicity, lethality, and effects on enzyme activity, and the toxicity to aquatic plants mainly manifests as reduction of plant cell biomass, interference with cell division, inhibition of photosynthesis, etc. The potential ecological risks to the marine environment caused by the large-scale use of amide herbicides cannot be ignored. Chloroacetamide herbicides are chemically stable and can exist in the marine environment and marine organisms for a long time. Isopropylamine and MEA degrade slowly in the environment. Among them, the hydrolysis half-life of isopropylamine in summer seawater is 67 days and the non-biodegradation half-life is 50 days. In winter seawater, the hydrolysis half-life is 277 days and the non-biodegradation half-life is 193 days. Therefore, it is urgent to develop a fast, efficient and safe method for remediating chloroacetamide herbicide pollution in the marine environment.

[0006] Patent application CN116042443A discloses an anaerobic degradation strain (Trichococcus sp. SRB-2), which is effective for the degradation of 20 mg·L -1 The anaerobic degradation half-life of isopropylamine was 2.0 days, and the degradation of MEA by this strain was not involved.

[0007] The existing document "Isolation, Identification and Degradation Characteristics of Isopropylamine-Degrading Strain Y4-6" (Master's thesis of Nanjing Agricultural University, Dong Yang, 2013) discloses a strain of Pseudoxanthomonas sp. that can degrade isopropylamine, but does not involve the degradation of MEA by this strain.

[0008] It can be seen that among the existing pesticide-degrading microorganisms, there is no strain that can degrade isopropylamine and MEA at the same time. Summary of the invention

[0009] In order to solve the shortcomings of the prior art, the object of the present invention is to provide a marine bacterium that can simultaneously degrade isopropylamine and MEA and has high degradation efficiency and is adaptable to a wide range of salinities.

[0010] In order to achieve the above object, the present invention adopts the following technical solution:

[0011] Paenibacillus contaminans WH-2, whose Latin name is Paenibacillus contaminans WH-2, is deposited in the General Microbiology Center of China Microorganism Culture Collection Administration. The deposit date is April 10, 2024, the deposit number is CGMCC No.30299, and the depository address is Beijing, China.

[0012] The application of the aforementioned Paenibacillus sp. WH-2 in the degradation of isopropylamine and 2-methyl-6-ethylaniline.

[0013] The invention is beneficial in that the Paenibacillus sp. WH-2 provided by the invention is separated and screened from marine shellfish in a sea area polluted by metolachlor. The strain is adaptable to a wide range of salinities, can efficiently degrade metolachlor and MEA, and has a highly efficient bioremediation effect on a marine environment (including seawater and marine sediments) polluted by metolachlor and MEA. The strain is used to treat marine shellfish polluted by metolachlor (at a concentration of 50 mg·L -1 ) and MEA (concentration of 50 mg·L -1 ) after 7 days of treatment with seawater contaminated by isopropylamine and MEA, the biodegradation rates reached 91.6% and 78.9%, respectively, and the degradation half-lives were 2.52 days and 3.56 days, respectively. After 7 days of treatment with the strain in marine sediments contaminated by isopropylamine (concentration of 50 mg / kg) and MEA (concentration of 50 mg / kg), the biodegradation rates of isopropylamine and MEA reached 87.3% and 73.5%, respectively, and the degradation half-lives were 3.06 days and 4.39 days, respectively. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is the colony morphology of Paenibacillus WH-2;

[0015] Figure 2 This is a diagram of the bacterial shape of Paenibacillus WH-2;

[0016] Figure 3 is the phylogenetic tree diagram of Paenibacillus WH-2;

[0017] Figure 4 This is a graph showing the growth test results of Paenibacillus sp. WH-2 at different temperatures;

[0018] Figure 5 This is a graph showing the growth test results of Paenibacillus WH-2 at different salinities;

[0019] Figure 6 This is a graph showing the growth test results of Paenibacillus sp. WH-2 at different pH values;

[0020] Figure 7 This is the statistical result of the degradation rate of isopropylamine and MEA by Paenibacillus sp. WH-2 at different inoculation amounts;

[0021] Figure 8 It is a statistical result graph of biodegradation rate of isopropylamine and MEA in contaminated seawater samples;

[0022] Fig. 9 It is a statistical graph of the biodegradation rates of isopropylamine and MEA in contaminated marine sediment samples. DETAILED DESCRIPTION

[0023] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] 1. Sample collection

[0025] In October 2022, tetrahedral clams were collected from a station (N38°07′28.86″, E118°13′51.07″) in the nearshore waters of the Yellow River Delta contaminated with isopropylamine. The tetrahedral clams were dissected under sterile conditions, and the mucus on the gills and hepatopancreas surface was scraped after rinsing twice with sterile saline. The scraped mucus was added to sterile saline (diluted), sealed, placed in an ice box and transported to the laboratory for use.

[0026] 2. Strain enrichment, screening, isolation and purification

[0027] 1. Culture medium preparation

[0028] Enrichment medium: weigh 19.45g sodium chloride, 5.98g magnesium chloride, 3.24g sodium sulfate, 1.80g calcium chloride, 0.55g potassium chloride, 0.16g sodium carbonate, 0.08g potassium bromide, 0.034g strontium chloride, 0.022g boric acid, 0.004g sodium silicate, 0.0024g sodium fluoride, 0.0016g sodium nitrate and 0.008g disodium hydrogen phosphate, heat and dissolve in 1000mL distilled water, and adjust the pH value to 7.6. Take 100mL of enrichment medium and dispense it into 250mL conical flasks, add 20 small glass beads with a diameter of 1mm to each flask, sterilize it by high pressure at 121℃ for 20min, and set aside.

[0029] Drug-free plate culture medium: prepare 1000 mL of enriched culture medium, add 15.0 g of agar, heat to dissolve and dispense into 250 mL conical flasks, sterilize at 121°C for 20 min, pour into plates and set aside.

[0030] Drug-containing plate culture medium: prepare 1000 mL of enrichment culture medium, add 100 mg of isopropylamine, 100 mg of MEA and 15.0 g of agar, heat to dissolve and dispense into 250 mL conical flasks, sterilize at 121°C for 20 min, pour into plates and set aside.

[0031] Improved LB medium: weigh 10 g tryptone, 5 g yeast extract and 19.45 g sodium chloride (the sodium chloride concentration of conventional LB medium is 5 g L -1 ~10g·L -1 ), dissolved in 1000 mL of distilled water, and the pH value was adjusted to 7.0. Take 100 mL of the modified LB medium and dispense it into a 250 mL conical flask, sterilize it by high pressure at 121°C for 20 min, and set aside.

[0032] 2. Enrichment and domestication of strains

[0033] Metolachlor and MEA were added to the enrichment medium at the same time, and the concentrations of both metolachlor and MEA were 20 mg·L -1 The diluted mucus obtained above was added to the enrichment medium supplemented with isopropylamine and MEA, and the mixture was incubated at 30°C and 150 r·min. -1 Enrichment culture was performed. Every 7 days, the culture was transferred to a new enrichment medium at a transfer rate of 5%. Each time the concentration of isopropylamine and MEA in the enrichment medium was gradually increased to 40 mg·L -1 、60mg·L -1 、80mg·L -1 、100mg·L -1After each transfer, samples were taken after 24 hours of incubation and sent to Shandong Provincial Aquatic Product Quality Inspection Center for gas chromatography-mass spectrometry to detect the residual amounts of isopropylamine and MEA and determine the degradation degree of isopropylamine and MEA.

[0034] Table 1 Degradation rates of metolachlor and MEA by cultures

[0035]

[0036] Table 1 shows that after 4 consecutive passages, the fifth generation culture was sensitive to high concentration (100 mg·L -1 ) The degradation rates of isopropylamine and MEA reached 69.8% and 59.6%, respectively.

[0037] 3. Isolation and purification of strains

[0038] Take 1 mL of the 5th generation culture and perform gradient dilution. Take 100 μL of 10 -3 , 10 -4 , 10 -5 , 10 -6 The diluted solutions of different dilution multiples were spread on drug-containing plate culture media (respectively marked as plate 1, plate 2, plate 3, and plate 4), and cultured in a constant temperature incubator at 30°C for 7 days.

[0039] Compared with other plates, plate 2 had more types of colonies and a moderate number. Multiple single colonies with different morphologies and colors were picked from plate 2 and streaked three times to obtain purified strains. The dominant strain (with larger colony diameter, regular morphology and edges, and smooth surface with protrusions) was selected and recorded as WH-2.

[0040] Metolachlor and MEA were added to the modified LB medium at the same time, and the concentrations of both metolachlor and MEA were 100 mg·L -1 The strain WH-2 was inoculated into the modified LB medium supplemented with isopropylamine and MEA and then grown at 150 r·min -1 The strain was cultured at 30°C on a shaker for 24 h and then preserved in 30% glycerol (stored at -70°C) as a backup strain.

[0041] 3. Colony morphology, bacterial shape, and physiological and biochemical characteristics of strain WH-2

[0042] 1. Colony morphology

[0043] Under sterile conditions, strain WH-2 was inoculated into drug-free plate medium using the three-line method. After 48 h of culture, Figure 1 As shown, it was observed that an opaque colony with a smooth surface, protrusions, round shape, regular edges and a diameter of about 1.0 mm was formed.

[0044] 2. Bacteria shape

[0045] Take two loops of freshly cultured strain WH-2 with an inoculation loop, add them to 1 mL of sterile water, and mix well. Take two copper holes for electron microscopy, cover with aspirated bacterial suspension for 3 minutes, dry the bacterial solution with filter paper, stain with phosphotungstic acid for 1.5 minutes, and dry the phosphotungstic acid with filter paper. Observe the shape of the bacteria under a Hitachi H-7650 transmission electron microscope, such as Figure 2 As shown, strain WH-2 is short rod-shaped and has no flagella.

[0046] 3. Physiological and biochemical characteristics

[0047] Identification by the API 20E bacterial identification system showed that strain WH-2 could assimilate and utilize arginine, sodium citrate, urea, and pyruvate, and could oxidize glucose, melastose, and arabinose, but could not assimilate and utilize o-nitrophenyl-galactoside, sodium thiosulfate, Kohn gelatin, mannitol, inositol, sorbitol, rhamnose, sucrose, and amygdalin, and could not hydrolyze lysine, ornithine, and tryptophan, and could not produce indole.

[0048] Species Identification of Strain WH-2

[0049] The genomic DNA was extracted by proteinase K cleavage, and 3 μL was taken for electrophoresis detection. The marker was DL9000, and the bands from top to bottom were 9000bp, 5000bp, 3000bp, 2000bp, 1000bp, and 500bp, respectively. The sample volume was 3 μL, and the bright band was 30 ng·μL -1 , the remaining bands were all 10 ng·μL -1 , P1, P2, and P3 are blank controls of extraction reagents.

[0050] The 16S rDNA fragment of strain WH-2 was amplified using the 16S full-length amplification forward primer 8F (nucleotide sequence: 5'-AGAGTTTGATCCTGGCTCAG-3') and reverse primer 8R (nucleotide sequence: 5'-TACGGYTACCTTGTTAYGACTT-3'). The amplified product was detected by 1% agarose gel electrophoresis and then sent to Feifan Standard Technology Service Co., Ltd. for sequencing.

[0051] The sequencing results were analyzed for homology using the BLAST search system and the 16S rDNA sequences of related species collected in the GenBank nucleic acid database, and the phylogenetic tree of strain WH-2 was constructed using the MEGA 7.0 software and the Neighbour-joining method. The construction results are shown in Figure 3 shown.

[0052] Comparative analysis showed that strain WH-2 was a Paenibacillus strain, which clustered with Paenibacillus contaminans and formed an independent internal branch. Therefore, strain WH-2 was named Paenibacillus contaminans WH-2.

[0053] 5. Growth of strain WH-2 under different temperature, salinity and pH conditions

[0054] 1. Detection of the growth of strain WH-2 at different temperatures

[0055] Take 500 μL of WH-2 culture medium grown to the exponential phase and inoculate it into the modified LB medium. -1 The cells were cultured on a shaker at 10, 15, 20, 25, 30, 35, 40, and 45 °C for 24 h. Three parallels were set up for each experimental group. The OD of the culture medium was measured at the beginning of the experiment and at 24 h using an ELISA reader. 600 The growth rate of the strain was measured by the OD value of the culture medium at 24h. 600 The OD of the culture medium at the beginning of the experiment 600 The difference (△OD 600 )express.

[0056] The results of strain growth test of strain WH-2 at different temperatures are as follows Figure 4 As shown. Figure 4 It can be seen that strain WH-2 can grow at 10℃~45℃, and the optimal growth temperature is 30℃.

[0057] 2. Growth detection of strain WH-2 under different salinities

[0058] The amount of sodium chloride added to the modified LB medium was adjusted. Specifically, the amount of sodium chloride added was 0 g, 10 g, 20 g, 30 g, 40 g, 50 g, 60 g, 70 g, 80 g, 90 g, and 100 g (dissolved in 1000 mL of distilled water), respectively, so that the salinity of the culture medium was 0, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, and 10%, respectively. 500 μL of WH-2 bacterial solution cultured to the exponential phase was inoculated into the culture medium with different salinities, and the culture medium was incubated at 150 r·min -1 The culture was incubated at 30°C for 24 h on a shaker. Three parallels were set up for each experimental group. The OD of the culture medium was measured at the beginning of the experiment and at 24 h using an ELISA reader. 600 The growth rate of the strain was measured by the OD value of the culture medium at 24 h. 600 The OD of the culture medium at the beginning of the experiment 600 The difference (△OD 600 )express.

[0059] The growth test results of strain WH-2 at different salinities are as follows Figure 5 As shown. Figure 5 It can be seen that the salinity range for the growth of strain WH-2 is 0-10%, and the optimal salinity is 3%-4%.

[0060] 3. Growth detection of strain WH-2 at different pH values

[0061] The pH value of the modified LB medium was adjusted to 3, 4, 5, 6, 7, 8, 9, and 10, respectively. 500 μL of WH-2 culture medium cultured to the exponential phase was inoculated into the culture medium with different pH values, and the mixture was incubated at 150 r·min. -1 The culture was incubated at 30°C for 24 h on a shaker. Three parallels were set up for each experimental group. The OD of the culture medium was measured at the beginning of the experiment and at 24 h using an ELISA reader. 600 The growth rate of the strain was measured by the OD value of the culture medium at 24h. 600 The OD of the culture medium at the beginning of the experiment 600 The difference (△OD 600 )express.

[0062] The growth test results of strain WH-2 at different pH values ​​are as follows Figure 6 As shown. Figure 6 It can be seen that the pH range for the growth of strain WH-2 is 3-10, and the optimal pH value for growth is 7-8.

[0063] In summary, strain WH-2 can grow at 10-45℃, pH 3-10, and sodium chloride concentration (w / v) 0-10%. The optimal growth temperature is 30℃, the optimal pH is 7-8, and the optimal salinity is 3%-4%. It has the characteristics of a wide temperature range, strong salt resistance and acid and alkali resistance, and is suitable for use in different marine environments.

[0064] VI. Degradation effect of strain WH-2 on metolachlor and MEA in marine environment

[0065] The above-mentioned improved LB medium was optimized and adjusted according to the optimal salinity (3% to 4%) of strain WH-2. Specifically, the amount of sodium chloride was further increased from 19.45g to 30g, that is, 10g of tryptone, 5g of yeast extract and 30g of sodium chloride were weighed and dissolved in 1000mL of distilled water, and the pH value was adjusted to 7.0 to obtain a high-salt LB medium. 100mL of high-salt LB medium was dispensed into a 250mL conical flask, autoclaved at 121℃ for 20min, and set aside.

[0066] 1. Degradation rate of isopropylamine and MEA by strain WH-2 at different inoculation rates

[0067] (1) Degradation rate of isopropylamine by strain WH-2 at different inoculation rates

[0068] Add metolachlor to the sterilized high-salt LB medium to a concentration of 50 mg / L -1 The strain WH-2 was inoculated into the high-salt LB medium supplemented with isopropylamine at an inoculum concentration of 0, 0.5%, 1%, 3%, 5%, 10%, 15%, and 20%, respectively. Three replicates were set up in each group and the culture was stirred at 150 r·min. -1 The mixture was cultured on a shaker at 30°C for 24 h. Samples were taken at 24 h and sent to Shandong Provincial Aquatic Product Quality Inspection Center for gas chromatography-mass spectrometry detection of the residual amount of metolachlor to determine the degree of degradation of metolachlor.

[0069] (2) Degradation rate of MEA by strain WH-2 at different inoculation rates

[0070] Add MEA to the sterilized high-salt LB medium to a concentration of 50 mg / L -1 The strain WH-2 was inoculated into the high-salt LB medium supplemented with MEA at an inoculum of 0, 0.5%, 1%, 3%, 5%, 10%, 15%, and 20%, respectively. Each group had three parallels and was incubated at 150 r·min -1 The mixture was cultured on a shaker at 30°C for 24 h. Samples were taken at 24 h and sent to Shandong Aquatic Products Quality Inspection Center for gas chromatography-mass spectrometry to detect the residual amount of MEA and determine the degree of MEA degradation.

[0071] The statistical results of the biodegradation rates of metolachlor and MEA by strain WH-2 at different inoculation rates are shown in Figure 7 .Depend on Figure 7 It can be seen that with the increase of the inoculation amount of strain WH-2, the degradation efficiency of isopropylamine and MEA was significantly improved. When the inoculation amount exceeded 5%, the degradation efficiency tended to balance. Therefore, the optimal inoculation amount of strain WH-2 was 5%.

[0072] 2. Cultivation of strain WH-2

[0073] The strain WH-2 was inoculated into high-salt LB medium and heated at 150 r·min -1 The culture was carried out on a shaker at 30°C for 24 h to obtain a fermentation broth.

[0074] 3. Preparation of contaminated seawater samples and marine sediment samples

[0075] Metolachlor and MEA were added to the seawater at the same time, and the concentrations of both metolachlor and MEA were 50 mg·L -1 , and obtain contaminated seawater samples.

[0076] Metolachlor and MEA were added to the marine sediments at the same time, and the concentration of both metolachlor and MEA was 50 mg kg -1 , to obtain samples of contaminated marine sediments.

[0077] 4. Treating contaminated samples with strain WH-2

[0078] The fermentation broth of strain WH-2 was added to contaminated seawater samples and contaminated marine sediment samples, respectively, with an inoculation amount of 5% (v / v), and the samples were left to stand at 30°C for 7 days.

[0079] During the static treatment period, samples were taken every 24 hours to detect the concentrations of isopropylamine and MEA, and the biodegradation rates and degradation half-lives of isopropylamine and MEA were calculated.

[0080] 5. Results

[0081] The statistical results of the biodegradation rates of metolachlor and MEA in contaminated seawater samples are shown in Figure 8 .Depend on Figure 8 It can be seen that after the contaminated seawater samples were treated with strain WH-2 for 7 days, the biodegradation rate of isopropylamine was 91.6%, and the degradation half-life was 2.52 days; the biodegradation rate of MEA was 78.9%, and the degradation half-life was 3.56 days.

[0082] The statistical results of the biodegradation rates of metolachlor and MEA in contaminated marine sediment samples are shown in Fig. 9 .Depend on Fig. 9 It can be seen that after the contaminated marine sediment samples were treated with strain WH-2 for 7 days, the biodegradation rate of isopropylamine was 87.3%, and the degradation half-life was 2.93 days; the biodegradation rate of MEA was 73.5%, and the degradation half-life was 4.39 days.

[0083] The above results indicate that strain WH-2 has a highly efficient bioremediation effect on marine environments (including seawater and marine sediments) contaminated by isopropylamine and MEA.

[0084] VII. Safety of strain WH-2 to marine animals and marine microalgae

[0085] The strain WH-2 was inoculated into high-salt LB medium and heated at 30°C and 150 r·min -1 The culture was shaken to the exponential phase at 5000 r / min. -1 Centrifuge for 5 minutes and collect the bacteria into sterile PBS buffer for later use.

[0086] 1. Safety of strain WH-2 to marine fish

[0087] Fingerlings of turbot (Scophthalmus maximus) were collected from Yantai, Shandong Province, and were temporarily reared in natural seawater (water temperature 25±0.5℃) for 7 days. During the rearing period, they were fed twice a day and the water was changed twice a day, with 2 / 3 of the water changed each time. The water was aerated continuously, feces were cleaned in time, and dead and unhealthy individuals were selected. Feeding was stopped one day before the experiment. Healthy finless fry of uniform size were selected as experimental subjects and divided into experimental and control groups, with 3 parallels in each group and 10 finless fry in each parallel.

[0088] The strain WH-2 was added to the water of the experimental group to a final concentration of 10 7 CFU·mL -1 The same dose of sterile PBS buffer was added to the water of the control group. During the experiment, the animals were fed once and the water was changed once every 24 hours, with 2 / 3 of the water changed each time. The water was continuously aerated and the feces were cleaned in time. The animals were observed for 7 consecutive days.

[0089] Observation results: The young fish in each group were healthy and energetic, and there was no mortality.

[0090] 2. Safety of strain WH-2 to marine copepods

[0091] Both Halicyclops sinensis Kiefer and Acartiapacifica were collected from the coastal waters of the Yellow River Delta. Natural seawater was filtered through a 0.45 μm mixed cellulose filter membrane and used at a water temperature of 20 ± 0.5 °C and a light-dark ratio of L:D = 12 h:12 h. After acclimation and culture for 3 days, 300 healthy and active adults were selected for the experiment. Experimental and control groups were set up, with 3 parallels in each group and 50 in each parallel, all of which were placed in 250 mL conical flasks.

[0092] The strain WH-2 was added to the water of the experimental group to a final concentration of 10 7 CFU·mL -1 The same dose of sterile PBS buffer was added to the control group water. Marine red yeast was fed once every 24 hours during the experiment, and the water was slightly aerated and observed for 3 consecutive days.

[0093] Observation results: Daphnia in each group survived normally and no death was observed.

[0094] 3. Safety of strain WH-2 on marine microalgae

[0095] Nitzschia closterium f.minutissima was provided by the Algae Seed Room of Shandong Institute of Marine Resources and Environment. Natural seawater and f / 2 culture medium were sterilized and used for the culture of Nitzschia closterium f.minutissima. The water temperature was 25±0.5℃, the light intensity was 3000lx, and the light-dark ratio was L∶D =12h∶12h. After three generations of pre-culture, the cells were normal under microscopic examination and the experiment was carried out in the logarithmic growth phase. Experimental and control groups were set up, with 3 parallels in each group. 100mL of logarithmic growth phase algae solution was taken from each parallel and placed in a 250mL conical flask.

[0096] The strain WH-2 was added to the water of the experimental group to a final concentration of 10 7 CFU·mL -1 The same dose of sterile PBS buffer was added to the control group water and observed for 3 consecutive days. The number of algal cells was counted under a microscope using a hemocytometer.

[0097] Statistical results: There was no significant difference in the number of algal cells among the groups.

[0098] The above results show that strain WH-2 7 CFU·mL -1 Concentrations of 200 mg / kg and below are relatively safe for marine fish, marine copepods and marine microalgae.

[0099] 8. Preservation of bacterial strains

[0100] Paenibacillus contaminans WH-2, whose Latin name is Paenibacillus contaminans WH-2, has been sent to the General Microbiology Center of China Microorganism Culture Collection Administration (CGMCC) for preservation. The preservation date is April 10, 2024, the preservation number is CGMCC No.30299, and the preservation unit address is Beijing, China.

[0101] It should be noted that the above embodiments are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the embodiments here. Any obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. Paenibacillus WH-2, Latin name Paenibacillus contaminans WH-2 is deposited in the General Microbiology Center of China Microbiological Culture Collection Administration, the deposit date is April 10, 2024, the deposit number is CGMCC No.30299, and the depository address is Beijing, China.

2. Use of the Paenibacillus sp. WH-2 according to claim 1 in the degradation of isopropylamine and 2-methyl-6-ethylaniline.

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