A salt-tolerant strain of Arthrobacterium and its microecological preparations and applications

Abstract

This invention belongs to the field of microbial technology and relates to a salt-tolerant Arthrobacter strain, its microecological preparations, and applications. The invention uses a salt-tolerant Arthrobacter strain derived from the rhizosphere of aquatic plants as the starting strain. Through ultraviolet mutagenesis, a new strain producing high levels of indoleacetic acid was obtained. This strain has been deposited at the China General Microbiological Culture Collection Center (CGMCC), accession number: CGMCC No. 30670. This bacterium possesses the ability to produce high levels of indoleacetic acid and can promote the growth of aquatic plants.

Description

Technical Field

[0001] This invention belongs to the field of microbial technology, and specifically relates to a salt-tolerant strain of Arthrobacterium and its microecological preparations and applications. Background Technology

[0002] Aquatic plants play a vital role in freshwater shrimp and crab farming. Firstly, they serve as essential plant-based food for farmed freshwater shrimp and crabs such as river crabs and crayfish. Consuming aquatic plants supplements the diet with vitamins and minerals, improving the utilization rate of artificial feed and reducing farming costs. Secondly, aquatic plants absorb excess ammonia nitrogen, nitrite, and other nutrients and harmful substances like heavy metals from the water. Through photosynthesis, they increase dissolved oxygen levels, improve bottom sediment, and accelerate the oxidation and decomposition of organic matter in the water. This contributes to stable water quality, maintains water clarity, and promotes healthy growth and improved quality of shrimp and crabs. Thirdly, aquatic plants provide habitats and hiding places for shrimp and crabs, increasing the effective space in the farming pond, reducing mortality during molting, and providing shade and cooling during hot seasons. They also act as a refuge from predators, contributing to increased shrimp and crab yields. Common aquatic plant species used in aquaculture ponds include: *Elodea nuttallii*, *Hydrilla verticillata*, *Alternanthera philoxeroides*, *Vallisneria natans*, and *Myriophyllum spicatum*.

[0003] In freshwater shrimp and crab farming, insufficient (unbalanced) nutrients in the pond bottom sediment or a lack of endogenous growth hormones often lead to problems in aquatic plant growth. This can manifest as slow growth, inability to meet aquaculture requirements, or underdeveloped root systems, resulting in the plants floating to the surface and dying. Therefore, selecting and breeding microorganisms that promote the decomposition of nutrients in the bottom sediment and secrete plant hormones, and then using them for aquatic plant cultivation, is of great significance for promoting aquatic plant growth and even improving the yield and quality of shrimp and crabs. Summary of the Invention

[0004] To address the aforementioned technical problems, the purpose of this invention is to provide a novel salt-tolerant strain of Arthrobacter.

[0005] The salt-tolerant Arthrobacter B34 provided by this invention was obtained by selecting and breeding a salt-tolerant Arthrobacter bacterium derived from the rhizosphere of aquatic plants through ultraviolet-nitrosoguanidine combined mutagenesis. This strain has the ability to produce high levels of indoleacetic acid.

[0006] The salt-tolerant Arthrobacter B34 provided by this invention was deposited on May 17, 2024, at the China General Microbiological Culture Collection Center (CGMCC), located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences. It is classified and named as Arthrobacter pascens, with accession number CGMCC No. 30670.

[0007] Furthermore, the 16S rRNA sequence of the salt-tolerant Arthroblast is shown in SEQ ID No. 1 of the sequence listing.

[0008] The present invention also provides a fermentation method for the aforementioned salt-tolerant Arthrobacter, specifically as follows:

[0009] (1) The activated salt-tolerant Arthroblasts were transferred to 250 mL LB liquid medium at an inoculation rate of 1% and cultured for 8 to 10 hours to serve as seed culture.

[0010] (2) The seed liquid was inoculated into a fermenter at an inoculation rate of 5% to 10% and cultured. The fermentation medium was: 10g glucose, 10g peptone, 1.0g potassium dihydrogen phosphate, 0.5g magnesium sulfate, 5g sodium chloride, 1000mL distilled water, pH 7.0 to 7.2.

[0011] Fermentation conditions: pH 7.0~7.2, temperature 30-33℃, rotation speed 100~200rpm, fermentation time 10~14h.

[0012] The present invention also provides a microbial preparation containing the aforementioned salt-tolerant Arthrobacter.

[0013] Furthermore, the microecological preparation contains the fermentation broth, powder, or granules of the halophilic Arthrobacter.

[0014] Preferably, the salt-tolerant Arthrobacter powder is a vacuum freeze-dried powder or a spray-dried powder;

[0015] Preferably, the salt-tolerant Arthrobacter granules are granulated from the salt-tolerant Arthrobacter powder and excipients.

[0016] The present invention also provides the application of the salt-tolerant Arthrobacter strain or the microecological preparation in promoting the growth of aquatic plants.

[0017] Furthermore, the aquatic plants include Elodea, Hydrilla verticillata, Vallisneria natans, Myriophyllum spicatum, Alternaria alternifolia, or Chlorella vulgaris.

[0018] The present invention also provides the application of the salt-tolerant Arthrobacter strain or the microecological preparation in the production of indoleacetic acid.

[0019] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0020] This invention provides a novel halophilic strain of *Arthrobacter*, which, after fermentation, produces up to 5870 mg / L of indoleacetic acid. Experimental results have verified that this strain can promote the growth and root development of aquatic plants. Attached Figure Description

[0021] Figure 1 Phylogenetic tree of 16S rDNA of *Arthrobacter halophilus* CGMCC No. 30670.

[0022] Figure 2 This is the standard curve for indoleacetic acid.

[0023] Figure 3 Comparison of indoleacetic acid content in different nitrosoguanidine mutagenized strains. Detailed Implementation

[0024] The present invention will be further described below with reference to embodiments. These embodiments are merely illustrative and not intended to limit the scope of the invention. The embodiments provided below can serve as a reference for further optimization and improvement by those skilled in the art, and are not intended to limit the invention in any way. The scope of the invention is not limited to the following embodiments.

[0025] Unless otherwise specified, the test methods in the following examples are conventional or standard methods and can be performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0026] Example 1: Screening of strains that solubilize phosphorus and potassium and produce indoleacetic acid

[0027] Collection of rhizosphere soil samples from aquatic plants: The roots of aquatic plants were completely dug out in the crab farming ponds, and a large amount of sediment on the roots was shaken off. The sediment that was finally attached to the root surface was taken as the rhizosphere soil of Elodea nuttallii for subsequent screening of phosphorus-solubilizing microorganisms. A total of 20 rhizosphere samples of aquatic plants were collected from the farming ponds. The aquatic plant species included: Elodea nuttallii, Hydrilla verticillata, Alternaria alternata, Vallisneria natans, and Myriophyllum spicatum.

[0028] Screening of phosphate-solubilizing bacteria: The collected rhizosphere samples of aquatic plants were prepared into sample dilutions of different concentrations (10... -1 10 -2 10 -3 10 -4 The bacteria were spread onto a phosphate-solubilizing culture medium. The selection medium for phosphate-solubilizing bacteria consisted of Monkina inorganic phosphorus medium: glucose 10.0 g, calcium phosphate 5.0 g, ammonium sulfate 0.5 g, sodium chloride 0.3 g, potassium chloride 0.3 g, magnesium sulfate heptahydrate 0.3 g, ferrous sulfate heptahydrate 0.03 g, manganese sulfate tetrahydrate 0.03 g, agar 20.0 g, and distilled water 1000 mL. The cultures were incubated upside down at 30°C for 3 days, with three replicates for each treatment. The formation and size of the clear zone were observed at 24 h, 48 h, and 72 h. Different colonies were selected based on their shape, size, and edge regularity, and purified onto a new solid phosphate-solubilizing culture medium. Purification was performed at least three times, resulting in a total of 78 phosphate-solubilizing bacteria strains.

[0029] Screening of potassium-solubilizing bacteria: The obtained phosphate-solubilizing bacteria strains were inoculated onto potassium-solubilizing bacteria solid culture medium. The culture medium consisted of: 5.0 g sucrose, 0.5 g magnesium sulfate heptahydrate, 2.0 g disodium hydrogen phosphate, 0.1 g calcium carbonate, 0.005 g ferric chloride, and 1.0 g mineral (potassium feldspar powder). The cultures were incubated upside down at 30°C for 3-5 days. The presence of a transparent hydrolysis zone around the colonies was observed. Strains with large, transparent, and glossy colonies and a transparent zone were selected as test strains. A total of 41 potassium-solubilizing bacteria strains were obtained.

[0030] Nitrogen-fixing bacteria screening: The phosphorus-solubilizing and potassium-solubilizing bacteria obtained above were inoculated onto Ashby nitrogen-free medium. The Ashby medium composition was: 10.0 g glucose, 0.2 g dipotassium hydrogen phosphate, 0.2 g magnesium sulfate, 0.2 g sodium chloride, 0.2 g calcium sulfate, 5.0 g calcium carbonate, 20.0 g agar, 1000 mL distilled water, pH 7.0–7.2. The medium was incubated upside down at 30°C for 3–5 days. Strains with large colonies were selected as test strains for screening indoleacetic acid-producing strains. The results showed that 20 strains could grow on Ashby nitrogen-free medium.

[0031] Screening of indoleacetic acid (IAA) strains:

[0032] (1) Salkowski colorimetric solution: This is a solution for identifying the ability to produce IAA. Accurately weigh 1.2g FeCl3, slowly add 30mL of deionized water, add 42.97mL of 98% concentrated sulfuric acid, and add the concentrated sulfuric acid while stirring with a glass rod, and make up to 100mL.

[0033] (2) Preparation of standard curve: Prepare indoleacetic acid standard solutions of different concentrations: 20 μg / mL, 40 μg / mL, 60 μg / mL, 80 μg / mL, and 100 μg / mL. Add 100 μL of each gradient standard solution to a 96-well plate, add 100 μL of colorimetric reagent, let stand for 20 min, and measure the absorbance at 530 nm. Construct a standard curve with absorbance as the x-axis and the concentration of the indoleacetic acid standard solution as the y-axis, as shown below. Figure 2 As shown.

[0034] (3) IAA production capacity determination of test strains: Single colonies of the test strains were picked and cultured in LB liquid medium at 30℃ and 180 rpm for 24 h on a shaker. 1 mL of fermentation broth was centrifuged at 12000 rpm for 2 min, and 100 μL of the supernatant was transferred to a 96-well plate. 100 μL of colorimetric reagent was added, and the plate was allowed to stand for 20 min. The absorbance was measured at 530 nm. The IAA concentration of each test strain was calculated based on the standard curve. The results of testing 20 strains of phosphorus-solubilizing and potassium-solubilizing nitrogen-fixing bacteria showed that 10 strains had the ability to produce IAA, with the highest content reaching 510 mg / L. B3-6, which had the highest IAA production, was selected for further mutagenesis treatment.

[0035] Mutagenesis and breeding in Example 2B3-6

[0036] The starting strain was B3-6, which underwent UV-nitrosoguanidine combined mutagenesis. The specific procedure is as follows:

[0037] Growth curve measurement: B3-6 was activated twice and inoculated into 500 mL of liquid culture medium, incubated at 30°C, and the OD value was measured every two hours. A growth curve was plotted with time on the x-axis and OD value on the y-axis. Simultaneously, the bacterial concentration was measured using an automated spiral inoculation system.

[0038] Preparation of bacterial suspension: After activating the starting strain twice, it was inoculated into 500 mL of liquid culture medium. According to the growth curve, it was cultured at 30℃ with shaking for 9–10 h until the logarithmic growth phase. The bacterial cells were collected by centrifugation and washed three times with sterile physiological saline to prepare 10... 7 CFU / mL ~10 8 CFU / mL bacterial suspension, for later use.

[0039] Ultraviolet (UV) mutagenesis lethality: 3–5 mL of bacterial suspension was placed in a sterile petri dish (6 cm in diameter) and irradiated under a 20W UV lamp at a distance of 28 cm for 10, 20, 40, 60, 120, and 240 seconds with stirring. Appropriate dilutions were made according to the mutagenesis time, and 100 μL of each dilution was plated, with three replicates for each dilution. The stock solution was then diluted to 10⁻⁶. -6 10 -7 10 -8 As a control, each dilution was performed in triplicate. Incubation was carried out at 30°C for 18–24 h. Lethality was calculated, and the results are shown in Table 1.

[0040] Table 1. Mortality rate induced by ultraviolet radiation

[0041] Mutagenesis time / s 10s 20s 40s 60s 120s 240s Comparison Mortality rate / % 28 42 55 77 85 99 -

[0042] Ultraviolet mutagenesis selection: The starting strain was subjected to ultraviolet mutagenesis at a mutagenesis time with a lethality rate of 70%–85%. 3–5 mL of bacterial suspension was placed in a sterile petri dish (6 cm in diameter) and placed under a 20W ultraviolet lamp at a distance of 28 cm. The irradiation time, with stirring, was the same as the mutagenesis time for a lethality rate of 70%–85%, i.e., 60 s and 120 s. The mutagenized bacterial suspension was inoculated into fresh liquid culture medium and incubated at 30°C in the dark for 18–24 h. After the bacterial suspension became turbid, it was spread on petri dishes to separate the bacteria. Strains with colony morphology significantly different from the starting strain were selected and subcultured three times in the dark. The surviving strains were stored at 4°C, and their indoleacetic acid (IAA) production capacity was then determined. Strain B3-6 showed the best performance, with an IAA production of 3045 mg / L in the fermentation broth.

[0043] Nitrosylguanidine mutagenesis lethality: The superior mutant strain B3-6, selected through ultraviolet mutagenesis, was activated to produce 10 7 CFU / mL ~10 8 CFU / mL bacterial suspension was used to prepare nitrosoguanidine solution at a ratio of 10 mg NTG: 1 mL acetone. The bacterial suspension was treated at a concentration of 0.3 g / L, 30℃, and 100 rpm for 30 min, 40 min, 50 min, and 60 min, respectively. Appropriate dilutions were made according to the mutagenesis time, and 100 μL of each solution was plated, with three replicates for each dilution. The stock solution was then diluted to 10... -6 10 -7 10 -8 As a control, each dilution was performed in triplicate. Incubation was carried out at 30°C for 18–24 h. Lethality was calculated, and the results are shown in Table 2.

[0044] Table 2. Nitrosylguanidine mutagenic mortality rate

[0045] Mutagenesis time / min 30 40 50 60 Comparison Mortality rate / % 59 66 84 98 -

[0046] Nitroguanidine mutagenesis and selection: The starting strain was mutagenized with nitrosoguanidine at a time when the lethality rate was 70%–85%. A nitrosoguanidine solution was prepared at a ratio of 10 mg NTG to 1 mL acetone and treated with the bacterial suspension at a concentration of 0.3 g / L, 37°C, and 100 rpm for 50 min. The mutagenized bacterial suspension was inoculated into fresh liquid culture medium and incubated at 30°C for 18–24 h. After the suspension became turbid, it was plated for separation. 100–200 strains with significant morphological changes compared to the starting strain were selected and subcultured three times. The 10–60 surviving strains were stored at 4°C for indoleacetic acid (IAA) production assay. Strain B34 showed the best performance, producing 5870 mg / L of IAA in the fermentation broth. Figure 3 As shown.

[0047] The 16S rDNA fragment of strain B34 was amplified using the universal bacterial 16S primers 5'-gagagtttgatcctggctcag-3' and 5'-cggctaccttgttacgactt-3'. Template DNA was extracted according to the bacterial DNA extraction kit instructions. The reaction mixture (20 μL) consisted of: 2 μL 10×PCR buffer, 0.5 μL each of primers (20 μmol / L), 2 μL dNTPs (2.5 mmol / L), 0.2 μL Taq enzyme (5 U / μL), 1 μL template DNA, and water to a final volume of 20 μL. Reaction conditions: 95℃ pre-denaturation for 5 min, 95℃ denaturation for 30 s, 55℃ annealing for 30 s, 72℃ extension for 30 s, for 30 cycles, followed by a final extension at 72℃ for 5 min.

[0048] After 16S rDNA sequencing of strain B34, the obtained gene sequence (SEQ ID No. 1 in the sequence listing) was compared with the 16S rDNA sequence in GenBank using BLAST analysis, and a phylogenetic tree was constructed using Mega4.0 software. Figure 1 The results showed that this strain had the highest homology (99%) with Arthrobacter pascens DSM 20545 published in GenBank, and the strain was identified as Arthrobacter pascens.

[0049] The obtained Arthrobacter pascens was deposited on May 17, 2024, at the China General Microbiological Culture Collection Center (CGMCC), located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences; its classification name is Arthrobacter pascens; and its accession number is CGMCC No. 30670.

[0050] Example 3: Preparation of fermentation broth for *Arthrobacter halophilus* CGMCC No. 30670

[0051] Cryopreserved *Arthrobacter halophilus* CGMCC No. 30670 was activated three times on LB agar plates. Single colonies were picked and inoculated into 10 mL LB liquid tubes and incubated at 30°C and 180 rpm for 10 hours. Then, a 1% inoculum was transferred to a 250 mL Erlenmeyer flask containing 100 mL LB medium and incubated for 8–10 hours to obtain the seed culture. The resulting seed culture was then inoculated into a 5 L fermenter containing 3 L of fermentation medium at a 5%–10% inoculum. The fermentation medium consisted of 10 g glucose, 10 g peptone, 1.0 g potassium dihydrogen phosphate, 0.5 g magnesium sulfate, 5 g sodium chloride, and 1000 mL distilled water, with a pH of 7.0–7.2. Fermentation was carried out at 30–33°C and 180 rpm for 10–14 hours. Fermentation was terminated when the indoleacetic acid content in the fermentation broth reached 5870 mg / L or higher, yielding the *Arthrobacter halophilus* fermentation broth with a viable count of 8.4 × 10⁻⁶ cells / mL. 9 CFU / mL.

[0052] Example 4: Preparation of Salt-Tolerant Bacillus CGMCC No. 30670 Powder

[0053] 10% porous starch and 5% cyclodextrin were added to the fermentation broth prepared in Example 3, mixed well, and then spray-dried. The inlet air temperature was 125°C, the outlet air temperature was 50°C, and the atomizer speed was 15000-18000 rpm, yielding *Bacillus halophilus* CGMCC No. 30670 bacterial powder. The viable count in the bacterial powder was 1.2 × 10⁻⁶. 11 CFU / mL.

[0054] Example 5: Preparation of Salt-Tolerant Bacillus CGMCC No. 30670 Particles

[0055] The bacterial powder obtained in Example 4 was mixed evenly with attapulgite clay at a ratio of 1%. The tilt angle of the drum granulator was adjusted to 45-60°, and the mixture of bacterial powder and attapulgite clay was fed into the drum granulator for granulation. Water mist was sprayed onto the material using a water mist sprayer, causing it to roll and form tiny particles. Microspheres with a particle size of 0.2-0.3 mm were screened out using a vibrating screen. The microspheres were then fed back into the drum granulator, and water mist was continuously sprayed onto the material using a water mist sprayer while adding the mixture of bacterial powder and attapulgite clay until the diameter of the bacterial particles increased to 2-3 mm. The bacterial particles were removed from the drum granulator and air-dried on a fluidized bed to obtain halophilic Bacillus thuringiensis CGMCC No. 30670 bacterial particles. The viable count in the bacterial particles was 1.0 × 10⁻⁶. 9 CFU / mL.

[0056] Example 6: Application of halophilic bacillus CGMCC No. 30670 in promoting the growth and root development of Elodea.

[0057] Cuttings of *Elodea nuttallii* (20cm) were selected, washed with clean water, disinfected with potassium permanganate solution, and then inserted into 15cm thick substrate modules (20cm x 20cm) made of garden soil. The planted substrate modules were placed in a 500L plastic bucket, and groundwater was added to a depth of 50cm at a temperature of 15-20 degrees Celsius. The experimental group used 50g of the bacterial granules prepared in Example 5, applied to the roots of the *Elodea nuttallii*. The control group used attapulgite granules without any bacteria. After 5 days of light cultivation, plant height and maximum root length were measured. The results are shown in Table 3. Using *Bacillus halophilus* CGMCC No. 30670 granules resulted in higher plant height and maximum root length for *Elodea nuttallii* compared to the control group, indicating that this bacterium promotes the growth of *Elodea nuttallii*.

[0058] Table 3. Plant height and maximum root length of *Elodea nuttallii* after 5 days of culture.

[0059]

[0060] Example 7: Application of halophilic bacillus CGMCC No. 30670 in promoting the growth of Chlorella.

[0061] Add 30 ml of Chlorella culture medium and 1 ml of Chlorella seed to a 50 ml Erlenmeyer flask, and then add the fermentation broth from Example 3 and the bacterial powder from Example 4, respectively, to achieve a viable cell count of 1.0 × 10⁻⁶. 6The concentration of CFU / mL was measured, with a control group also included. Each group had three replicates. All samples were cultured in an artificial climate chamber (25℃, light intensity 125 lx, light-dark ratio 14:10, shaking 3 times / day). After 5 days of culture, the number of Chlorella cells was counted using a hemocytometer. The results are shown in Table 4. The number of Chlorella cells was significantly higher in the control group after using the fermentation broth or powder of *Bacillus halophilus* CGMCC No. 30670, indicating that this bacterium promotes the growth of Chlorella.

[0062] Table 4. Number of Chlorella after 4 days of cultivation

[0063]

[0064] SEQ ID No.1

[0065] CCGGTGCGGCGTGCTTACCTGCAAGTCGAACGATGATCTCCAGCTTGCTGG

[0066] GGGGATTAGTGGCGAACGGGTGAGTAACACGTGAGTAACCTGCCCTTAAC

[0067] TCTGGGATAAGCCTGGGAAACTGGGTCTAATACCGGATATGACTCCTCATCG

[0068] CATGGTGGGGGGTGGAAAGCTTTTGTGGTTTTGGATGGACTCGCGGCCTAT

[0069] CAGCTTGTTGGTGAGGTAATGGCTCACCAAGGCGACGACGGGTAGCCGGC

[0070] CTGAGAGGGTGACCGGCCACACTGGGACTGAGACACGGCCCAGACTCCTA

[0071] CGGGAGGCAGCAGTGGGGAATATTGCACAATGGGCGCAAGCCTGATGCAG

[0072] CGACGCCGCGTGAGGGATGACGGCCTTCGGGTTGTAAACCTCTTTCAGTAG

[0073] GGAAGAAGCGAAAGTGACGGTACCTGCAGAAGAAGCGCCGGCTAACTAC

[0074] GTGCCAGCAGCCGCGGTAATACGTAGGGCGCAAGCGTTATCCGGAATTATT

[0075] GGGCGTAAAGAGCTCGTAGGCGGTTTGTCGCGTCTGCCGTGAAAGTCCGG

[0076] GGCTCAACTCCGGATCTGCGGTGGGTACGGGCAGACTAGAGTGATGTAGG

[0077] GGAGACTGGAATTCCTGGTGTAGCGGTGAAATGCGCAGATATCAGGAGGA

[0078] ACACCGATGGCGAAGGCAGGTCTCTGGGCATTAACTGACGCTGAGGAGCG

[0079] AAAGCATGGGGAGCGAACAGGATTAGATACCCTGGTAGTCCATGCCGTAAA

[0080] CGTTGGGCACTAGGTGTGGGGGACATTCCACGTTTTCCGCGCCGTAGCTAA

[0081] CGCATTAAGTGCCCCGCCTGGGGAGTACGGCCGCAAGGCTAAAACTCAAA

[0082] GGAATTGACGGGGGCCCGCACAAGCGGCGGAGCATGCGGATTAATTCGAT

[0083] GCAACGCGAAGAACCTTACCAAGGCTTGACATGGACCGGACCGCCGCAGA

[0084] AATGTGGTTTCCCCTTTGGGGCCGGTTCACAGGTGGTGCATGGTTGTCGTC

[0085] AGCTCGTGTCGTGAGATGTTGGGTTAAGTCCCGCAACGAGCGCAACCCTC

[0086] GTTCCATGTTGCCAGCGCGTAATGGCGGGGACTCATGGGAGACTGCCGGG

[0087] GTCAACTCGGAGGAAGGTGGGGACGACGTCAAATCATCATGCCCCTTATGT

[0088] CTTGGGCTTCACGCATGCTACAATGGCCGGTACAAAGGGTTGCGATACTGT

[0089] GAGGTGGAGCTAATCCCAAAAAGCCGGTCTCAGTTCGGATTGGGGTCTGC

[0090] AACTCGACCCCATGAAGTCGGAGTCGCTAGTAATCGCAGATCAGCAACGCT

[0091] GCGGTGAATACGTTCCCGGGCCTTGTACACACCGCCCGTCAAGTCACGAA

[0092] AGTTGGTAACACCCGAAGCCGGTGGCCTAACCCCTTGTGGGAGGGAGCTT

[0093] CGAAGGGGGACCCAA。

Claims

1. A strain of salt-tolerant Arthrobacter ( Arthrobacter pascens ) strain, characterized in that, Its accession number is CGMCCNo.30670.

2. The fermentation method of halophilic bacteria according to claim 1, characterized in that, (1) The seed culture medium used was LB medium, and the fermentation medium used was: 10 g glucose, 10 g peptone, 1.0 g potassium dihydrogen phosphate, 0.5 g magnesium sulfate, 5 g sodium chloride, 1000 mL distilled water, pH 7.0~7.2; (2) The activated salt-tolerant Arthroblasts were transferred to LB liquid medium at an inoculation rate of 1% and cultured for 8-10 hours to serve as seed culture. (3) The seed liquid is inoculated into a fermenter at an inoculation rate of 5% to 10% for culture; Fermentation conditions: pH 7.0~7.2, temperature 30~33℃, rotation speed 100~200 rpm, fermentation time 10~14h.

3. A microecological preparation containing the salt-tolerant Arthrobacterium as described in claim 1.

4. The microecological preparation according to claim 3, characterized in that, The microecological preparation contains the fermentation broth, powder, or granules of the halophilic Arthrobacter.

5. The microecological preparation according to claim 4, characterized in that, The salt-tolerant Arthrobacter powder is either vacuum freeze-dried or spray-dried.

6. The microecological preparation according to claim 4, characterized in that, The salt-tolerant Arthrobacter granules are granulated from the salt-tolerant Arthrobacter powder and excipients.

7. The application of the salt-tolerant Arthrobacter strain of claim 1 or the microecological preparation of any one of claims 3 to 6 in promoting the growth of aquatic plants.

8. The application according to claim 7, characterized in that, The aquatic plants include Elodea, Hydrilla verticillata, Vallisneria natans, Myriophyllum spicatum, Alternaria alternifolia, or Chlorella vulgaris.

9. The use of the salt-tolerant Arthrobacter strain according to claim 1 or the microecological preparation according to any one of claims 3 to 6 in the production of indoleacetic acid.

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