Exiguobacterium acetylbacter and application thereof

Abstract

The invention relates to the technical field of microorganisms, in particular to an Exiguobacterium aceticum and application thereof. The Exiguobacterium aceticum strain is classified and named as Exiguobacterium aceticum, the strain number is H102, the Exiguobacterium aceticum strain is preserved in the China General Microbiological Culture Collection Center (CGMCC) on December 24, 2025, and the preservation number is CGMCC No.37157. The Exiguobacterium aceticum strain has the advantages that the Exiguobacterium aceticum strain can be used for preparing the Exiguobacterium aceticum strain; the strain has strong saline-alkaline tolerance, drought tolerance and high temperature resistance, and a foundation is provided for colonization of the strain. Meanwhile, the strain has the functional characteristics of producing acetoin, polysaccharide and polyglutamic acid and the like, can effectively provide nutritional ingredients for plant growth and reduce the harm of abiotic stress to the plants, and therefore, the strain has important application value in the aspects of improving saline-alkali soil, improving abiotic stress resistance of the plants, promoting plant growth and the like.

Description

Technical Field

[0001] This invention relates to the field of microbial technology, specifically to a strain of Microbeluga acetylcholine and its applications. Background Technology

[0002] In agricultural production, the large-scale input of chemical fertilizers and pesticides has long been relied upon to maintain and increase crop yields and prevent plant diseases. While these agrochemicals have played a significant role in boosting short-term productivity, their overuse has led to a series of serious problems, such as damaging soil microbial diversity, increasing pesticide resistance in plant pathogens, reducing soil fertility, and causing soil pollution. More importantly, current chemical fertilizer use in many regions is approaching or has reached the point of diminishing returns; even continued increases in input are unlikely to achieve further increases in crop yields and may even exacerbate environmental burdens. Therefore, developing environmentally friendly and sustainable agricultural inputs has become an urgent need for agricultural development.

[0003] Microbial fertilizers are considered an environmentally friendly option, especially functional microbial agents with Plant Growth-Promoting Rhizobacteria (PGPR) as their core. By colonizing the plant rhizosphere, they can exert their growth-promoting effects directly or indirectly. They are regarded as one of the effective ways to replace or reduce the use of chemical fertilizers and pesticides, so as to achieve "reduced fertilizer use and increased efficiency" and safe production in agriculture.

[0004] However, the research and application of existing microbial fertilizers still have significant limitations. Currently, the resources of PGPR strains that have been successfully commercialized or widely used are relatively limited, and their functional characteristics are often developed for conventional soil conditions, making it difficult to meet the needs of complex and diverse adverse environments. For example, in saline-alkali soils, the survival and colonization ability and growth-promoting function of ordinary PGPR strains are severely inhibited, leading to unstable or even ineffective application. Therefore, screening microbial strains suitable for adverse environments such as saline-alkali soils and possessing highly efficient growth-promoting capabilities can compensate for the technical shortcomings of existing microbial fertilizers, such as their single function and poor stress resistance. Furthermore, it has extremely important strategic significance for the development and utilization of land resources in adverse environments. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a strain of Acetylmicrobacterium to address the shortcomings of the prior art.

[0006] Another technical problem that the present invention needs to solve is to provide the application of the aforementioned Acetylmicrobacterium.

[0007] The final technical problem to be solved by this invention is to provide a microbial growth promoter.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0009] A strain of *Exiguobacterium acetylicum*, classified as *Exiguobacterium acetylicum*, with strain number H102, was deposited on December 24, 2025, at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC No. 37157. The deposit address is Institute of Microbiology, Chinese Academy of Sciences, No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing.

[0010] The acetylmicrobacterium was isolated from the saline-alkali area (N32) of Yancheng City, Jiangsu Province. o 46', E120 o 56') of the rhizosphere soil of Suaeda salsa.

[0011] The 16S rRNA gene sequence of the *Acetylmicrobacterium* is shown in SEQ ID NO.1.

[0012] The acetylmicrobacterium can grow normally under the following conditions: NaCl content 0~1.2 mol / L, and / or polyethylene glycol content 0~20% w / v, and / or pH 6~12, and / or 24~40℃.

[0013] The application of *Microbacterium acetylcholine* in the fermentation production of acetoin is also within the scope of protection of this invention.

[0014] The application of *Microbacterium acetylcholine* in the fermentation production of polysaccharides is also within the scope of protection of this invention.

[0015] The application of *Microbacterium acetylcholine* in the fermentation production of polyglutamic acid is also within the scope of protection of this invention.

[0016] The application of the aforementioned acetylmicrobacterium in promoting crop growth is also within the scope of protection of this invention.

[0017] The application of the aforementioned acetylmicrobacterium in enhancing crop resilience to abiotic stress is also within the scope of protection of this invention.

[0018] The crops mentioned are tomatoes and / or corn.

[0019] The abiotic stresses include any one or a combination of several of the following: salt-alkali stress, drought stress, and high-temperature stress.

[0020] The present invention also provides a microbial growth promoter.

[0021] The microbial growth promoter contains the fermentation broth of the acetylmicrobacterium.

[0022] The concentration of the fermentation broth is 10. 5 ~10 11 CFU / mL.

[0023] Beneficial effects:

[0024] This invention provides a strain of *Exiguobacterium acetylicum* H102 isolated and screened from the rhizosphere soil of the halophyte *Suaeda salsa*, which was deposited on December 24, 2025, at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC No. 37157. This strain exhibits strong tolerance to salinity, drought, and high temperatures, providing a foundation for its colonization. Furthermore, this strain possesses functional characteristics such as acetoin production, polysaccharide production, and polyglutamic acid production, effectively providing nutrients for plant growth, reducing the harm caused by abiotic stress, and ultimately promoting plant growth. Therefore, the H102 strain has significant application value in saline-alkali soil improvement, enhancing plant tolerance to abiotic stress, and promoting plant growth. Attached Figure Description

[0025] The present invention will be further described in detail below with reference to the accompanying drawings, and the advantages of the present invention in the above and / or other aspects will become clearer.

[0026] Figure 1 This is a colony morphology diagram of Acetylmicrobacterium H102.

[0027] Figure 2 This is a Gram staining result of Acetylmicrobacterium H102.

[0028] Figure 3 This is a growth curve of Microbacterium acetylcholine H102.

[0029] Figure 4 This is a graph showing the growth of *Acetobacter acetylcholine* H102 at different salt concentrations.

[0030] Figure 5 This image shows the growth of *Microbacterium acetylcholine* H102 under different PEG-6000 conditions.

[0031] Figure 6 This is a diagram showing the growth of *Acetobacter acetylcholine* H102 under different pH conditions.

[0032] Figure 7 This is a diagram showing the growth of *Acetobacter acetylcholine* H102 under different temperature conditions.

[0033] Figure 8 This is a diagram of the VP assay for Acetylmicrobacterium H102.

[0034] Figure 9 Standard curve for the determination of acetoin content in Microbacterium acetylcholine H102.

[0035] Figure 10 Standard curve for determining the polysaccharide content of Acetylmicrobacterium H102.

[0036] Figure 11 Standard curve for determining polyglutamic acid content in Microbacterium acetylcholine H102.

[0037] Figure 12 The effect of acetylmicrobacterium H102 on the growth promotion of tomato seedlings.

[0038] Figure 13 The effect of acetylmicrobacterium H102 on the growth promotion of maize. Detailed Implementation

[0039] The present invention will be further described in detail below with reference to specific embodiments, and the advantages of the present invention in the above and / or other aspects will become clearer.

[0040] Unless otherwise specified, the experimental methods described in the following examples are conventional methods; the reagents and materials described are commercially available unless otherwise specified.

[0041] The culture medium, reagents, and materials used in this invention are as follows:

[0042] (1) LB medium, the formula is: sodium chloride 10 g / L, tryptone 10 g / L, yeast extract powder 5 g / L, pH adjusted to 7.0, sterilized at 121℃ for 20 min.

[0043] (2) 600 mmol NaCl LB liquid medium (salted LB medium), the formula is: 10 g / L tryptone, 5 g / L yeast powder, 45.1 g / L NaCl, pH adjusted to 7.0, sterilized at 121℃ for 20 min.

[0044] (3) 1 / 10 LB liquid medium with 600 mmol NaCl (1 / 10 LB medium with added salt), the formula is: 1 g / L tryptone, 0.5 g / L yeast extract, 4.51 g / L NaCl, pH adjusted to 7.0, sterilized at 121℃ for 20 min.

[0045] (4) FJ medium, the formula of which is: glucose 10 g / L, dipotassium hydrogen phosphate 1.5 g / L, potassium dihydrogen phosphate 1.5 g / L, peptone 10 g / L, magnesium sulfate 1.5 g / L, pH adjusted to 7.0, sterilized at 121℃ for 20 min.

[0046] (5) Glucose peptone medium, the formula of which is: 7 g / L peptone, 5 g / L glucose, 5 g / L dipotassium hydrogen phosphate, pH 7.1~7.2, sterilized at 115℃ for 20 min.

[0047] (6) Nitrogenous medium, the formula is: sucrose 10.0 g / L, (NH4)2SO4 1 g / L, MgSO4·7H2O 0.5 g / L, NaCl 0.1 g / L, K2HPO4 2 g / L, yeast extract 0.5 g / L, adjust the pH to 7.5, solid medium with 20 g / L agar, liquid medium without agar.

[0048] (7) DF medium and ADF medium: purchased from Shanghai Yuanye Biotechnology Co., Ltd., storage conditions: 2~8℃.

[0049] (8) 0.5% Creatine: Weigh 0.25 g of creatine accurately, dissolve it in distilled water, and bring the volume up to 50 mL.

[0050] (9) 5% Naphthol: Accurately weigh 2.5 g of Naphthol, dissolve it in anhydrous ethanol, and make up to 50 mL. Prepare fresh before use.

[0051] (10) 10% potassium hydroxide solution: Weigh 2.5 g of potassium hydroxide accurately, dissolve it in distilled water, and make up to 50 mL.

[0052] This invention's deposit information: A strain of *Exiguobacterium acetylicum*, classified as *Exiguobacterium acetylicum*, with strain number H102 and deposit number CGMCC No. 37157, was deposited on December 24, 2025, at the China General Microbiological Culture Collection Center, Institute of Microbiology, Chinese Academy of Sciences, No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing.

[0053] Example 1: Isolation and purification of strains

[0054] Samples were collected from the saline-alkali area (N32) of Yancheng City, Jiangsu Province using sterile sampling bags. o 46', E120 o 56') of rhizosphere soil from *Suaeda salsa* was collected and brought back to the laboratory for preservation. 0.5 g of rhizosphere soil from *Suaeda salsa* was weighed and placed in an Erlenmeyer flask containing 4.5 mL of sterile water. The flask was shaken at 200 r / min and 30℃ for 30 min. The soil suspension was then serially diluted, and 10 g samples were taken from each flask. -2 10 -3 10 -4 10 -5100 µL of each diluted soil suspension was spread onto 1 / 10 LB medium containing 600 mM NaCl using the dilution-spreading method and incubated at 30°C for 48 h. Single colonies were picked and purified by streak plating three times to obtain pure culture of strain H102. The strain morphology is as follows: Figure 1 As shown. The strain was inoculated into 1 / 10 LB liquid medium containing 600 mM NaCl and cultured for 24 h. Then, it was stored in an ultra-low temperature freezer at -80°C using the glycerol preservation method for later use.

[0055] Example 2: Identification of strain H102

[0056] The 16S rRNA gene sequence of strain H102 was amplified and compared. Specifically, PCR amplification was performed using a single colony of H102 obtained from pure culture in Example 1 as a template, with the universal bacterial primers 27F / 1492R used. The PCR amplification system was 20 μL: 2 μL primer 27F (5'-AGAGTTTGATCCTGGCTCAG-3'), 2 μL primer 1492R (5'-GGTTACCTTGTTACGACTT-3'), 4 μL ddH2O, 2 μL DNA, and 10 μL rTaq polymerase (5 U / μL). -1 Takara Biotechnology (Dalian) Co., Ltd., Dalian, China. The PCR program was set as follows: 95℃ pre-denaturation for 10 min; 95℃ pre-denaturation for 15 s, 55℃ annealing for 15 s, 72℃ extension for 1 min, 35 cycles; final extension at 72℃ for 5 min, and storage at 4℃ for 5 min. The PCR-amplified gene fragments were detected using agarose gel electrophoresis (1.0%) at 200 V for 20 min. Sequencing of the PCR-amplified gene fragments was performed by a sequencing company. The sequencing results of the 16S rRNA of strain H102 are shown in SEQ ID NO. 1. BLAST alignment of the 16S rRNA sequence of strain H102 showed the highest homology with *Exiguobacterium acetylicum*.

[0057] Morphological observation of strain H102 was performed. Single colonies of strain H102 were isolated by streaking in three zones on solid LB medium. It was observed that the colonies of strain H102 were round, orange, moist, and had smooth edges without protrusions.

[0058] Further Gram staining of the strain revealed a purple color, such as... Figure 2 As shown, this indicates that strain H102 is a Gram-positive bacterium.

[0059] Based on molecular identification, morphological observation, and Gram staining results, strain H102 was identified as *Exiguobacterium acetylicum*. This strain was deposited at the China General Microbiological Culture Collection Center (CGMCC) on December 24, 2025, and named *Exiguobacterium acetylicum*, with strain number H102 and accession number CGMCC No. 37157. The deposit address is Institute of Microbiology, Chinese Academy of Sciences, No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing.

[0060] Example 3: Identification of growth conditions for strain H102

[0061] 1. Growth curve determination of strain H102

[0062] Single colonies of strain H102 were picked and placed in LB broth, incubated on a constant temperature shaking incubator at 30°C and 200 r / min. The absorbance of the bacterial solution at 600 nm was measured using a UV spectrophotometer. The OD value of the bacterial solution was then determined. 600 The absorbance was 0.6–0.8. The bacterial culture was inoculated into FJ liquid medium at a 2% v / v inoculum and cultured on a constant temperature shaking incubator at 30°C and 200 r / min. The absorbance at 600 nm was measured periodically using a UV spectrophotometer, and a growth curve was plotted. The results are shown below. Figure 3 As shown, strain H102 exhibits good growth characteristics and stable metabolic performance, providing reference data for the subsequent production of this strain.

[0063] 2. Salt tolerance of strain H102

[0064] The H102 strain was inoculated into salted LB broth and cultured at 30℃ and 200 r / min for 24 h. Then, it was inoculated at a 1% v / v rate into FJ broth with NaCl concentrations of 0 mol / L, 0.1 mol / L, 0.3 mol / L, 0.6 mol / L, 1.2 mol / L, 1.8 mol / L, 2.1 mol / L, 2.4 mol / L, 2.6 mol / L, 2.8 mol / L, and 3.0 mol / L. The fermentation broth was continuously cultured in a shaker at 30℃ and 200 r / min. Samples of the fermentation broth were taken in a clean bench at 3 h, 6 h, 9 h, 12 h, 15 h, 18 h, 24 h, 36 h, 48 h, 60 h, 72 h, 84 h, 96 h, 108 h, 120 h, and 125 h to determine the OD of the bacterial culture. 600 The value is repeated 3 times for each group.

[0065] The results are as follows Figure 4 As shown, strain H102 can grow normally under salt concentrations of 0–1.2 mol / L, demonstrating excellent salt stress tolerance, which lays the foundation for the colonization and application of this bacterium in saline-alkali land.

[0066] 3. Drought tolerance of strain H102

[0067] Using LB medium with added salt as the seed culture, strain H102 was inoculated and cultured for 12 h in a shaker at 30℃ and 200 r / min. Then, at a 1% v / v inoculation rate, it was inoculated into FJ liquid medium supplemented with 0%, 5%, 10%, 20%, 30%, 40%, 50%, and 60% polyethylene glycol (PEG-6000) (g / 100 mL) with a molecular weight of 6000, respectively, and cultured at 30℃ and 200 r / min. Samples of the fermentation broth were taken in a clean bench at 3 h, 6 h, 9 h, 12 h, 15 h, 18 h, 24 h, 36 h, 48 h, 60 h, 72 h, 84 h, 96 h, 108 h, 120 h, and 125 h to determine the OD value of the bacterial culture. 600 The value is repeated 3 times for each group.

[0068] The results are as follows Figure 5 As shown, strain H102 can tolerate drought well under conditions of 0-10% PEG-6000. It can still grow when the concentration of PEG-6000 is as high as 20%, indicating that strain H102 has excellent drought resistance.

[0069] 4. Alkali tolerance of strain H102

[0070] The H102 strain was inoculated at a rate of 1% v / v into 250 mL Erlenmeyer flasks containing 100 mL of salt-added LB medium. The initial pH was adjusted to 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, 11.0, and 12.0, respectively. The flasks were then incubated at 30℃ and 200 rpm for 24 h. The OD of the bacterial culture was then measured. 600 value.

[0071] The results are as follows Figure 6 As shown, strain H102 can grow normally under conditions of pH 6-12, demonstrating alkali tolerance, which provides a basis for the application of this strain in saline-alkali land.

[0072] 5. The high-temperature resistance of strain H102

[0073] The H102 strain was inoculated at a rate of 1% v / v into 250 mL Erlenmeyer flasks containing 100 mL of salt-added LB medium. The different groups of Erlenmeyer flasks were then incubated in shakers at 24℃, 30℃, 37℃, and 40℃, respectively, at a rotation speed of 200 r / min. The OD of the bacterial culture was measured after 24 h of incubation. 600 value.

[0074] The results are as follows Figure 7 As shown, strain H102 can grow normally in the range of 24~40℃, and has the ability to withstand high temperatures.

[0075] Example 4: Functional identification of strain H102

[0076] 1. Acetonitrile production ability of strain H102

[0077] VP test: First, in a clean bench, 2.5 mL of glucose-peptone aqueous medium was inoculated with activated H102 strain. After incubation at 30°C inverted for 96 h, the culture was removed for the VP test. 0.6 mL of 6% α-naphthol anhydrous ethanol solution and 0.2 mL of 40% KOH solution were added sequentially. After shaking and standing for 3 min, VP-positive bacteria would turn red; if no red color appeared, the result was negative. Results are as follows... Figure 8 As shown, strain H102 appears red and is a positive bacteria.

[0078] Plotting the acetoin standard curve: Prepare acetoin solutions with different concentration gradients. Specifically, prepare 1 g / L acetoin standard solution and 10 mL centrifuge tubes, setting concentration gradients of 0, 0.02, 0.04, 0.06, 0.08, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.8, and 1.0 g / L. Different concentration gradients of acetoin solutions are obtained by dilution at different ratios. Add 0.1 mL of each diluted acetoin standard solution to a 5 mL centrifuge tube, with three replicates for each concentration gradient. Add 1 mL of 5% naphthol solution (dissolved in anhydrous ethanol), 1 mL of 10% potassium hydroxide, and 1 mL of 0.5% creatine solution sequentially to each tube (the order of addition must not be reversed). Shake well and heat in a water bath at 30°C for 30 min. Pipette 0.2 mL of each liquid into a 96-well plate and measure its OD. 540 The preparation yielded as follows Figure 9 The standard curve of acetoin is shown.

[0079] Assay for acetoin yield in fermentation broth: A single colony of activated H102 strain was picked up with a pipette tip and inoculated into a 10 mL centrifuge tube containing 3 mL of glucose-peptone aqueous medium. The culture was incubated at 30°C for 48 h using a shaker. 2 mL of H119 fermentation broth was centrifuged at 8000 r / min for 10 min. 0.1 mL of the supernatant was transferred to a 5 mL centrifuge tube, and 1 mL of 5% naphthol solution (dissolved in anhydrous ethanol), 1 mL of 10% potassium hydroxide, and 1 mL of 0.5% creatine solution were added (the order of addition must not be reversed). The mixture was shaken well and heated in a 30°C water bath for 30 min. The OD value in the centrifuge tube was then measured. 540 The yield of acetoin in the fermentation broth was obtained by comparing with the standard curve, and the yield of acetoin produced by strain H102 was measured to be 425 mg / L.

[0080] 2. Polysaccharide production capacity of strain H102

[0081] The H102 strain, preserved at -80℃, was removed from the freezer and activated by streak plating on nitrogenous solid medium. It was then incubated at 30℃ for 48 h. The colonies were observed to be moist and glossy, exhibiting a stringy, viscous texture when lifted with a toothpick, indicating that the H102 strain possesses polysaccharide-producing characteristics. A single colony of the H102 strain was picked and placed in a 10 mL centrifuge tube containing 3 mL of nitrogenous medium. The culture was carried out at 30℃ and 200 rpm for 72 h. The polysaccharide yield of the H102 strain was determined according to the polysaccharide content determination method in the liquid sample polysaccharide content kit from Suzhou Greens Biotechnology Co., Ltd., and the final polysaccharide yield was 0.1145 mg / mL. Figure 10 Standard curve for determining the polysaccharide content of Acetylmicrobacterium H102.

[0082] 3. Polyglutamic acid production capacity of strain H102

[0083] Strain activation culture: In a clean bench, use a sterile pipette tip to take a small amount of bacterial suspension stored at -80℃ and inoculate it into LB agar medium by streak plating. Incubate upside down in a 37℃ incubator for 48 h; then subculture 2-3 times.

[0084] Seed culture: Pick up the activated inoculum with a pipette tip and inoculate it into a 10 mL centrifuge tube containing 3 mL of seed culture medium (10 g / L glucose, 10 g / L peptone, 20 g / L sodium glutamate, 1.0 g / L magnesium sulfate heptahydrate, 5.0 g / L sodium chloride and 0.5 g / L dipotassium hydrogen phosphate). Incubate overnight at 37°C and 200 rpm to obtain the seed culture.

[0085] Fermentation culture: 200 μL of seed culture was inoculated into a 10 mL centrifuge tube containing 3 mL of fermentation medium (35 g / L sucrose, 20 g / L peptone, 40 g / L monosodium glutamate, 1.0 g / L magnesium sulfate heptahydrate, 5.0 g / L sodium chloride, 0.1 g / L calcium chloride, 0.5 g / L dipotassium hydrogen phosphate, 0.2 g / L manganese sulfate, and 10 g / L defoamer) and incubated at 37℃ and 200 rpm for 96 h.

[0086] γ-PGA yield was determined using the CTAB turbidimetric method. 1 mL of fermentation broth was taken, and 4 mL of sterile water was added. The mixture was thoroughly mixed by pipetting. After centrifugation at 10,000 rpm for 15 min, 1 mL of the supernatant was collected. 3 mL of anhydrous ethanol was added to the supernatant, and the mixture was thoroughly mixed by inverting. The mixture was then placed in a 4°C refrigerator and allowed to stand overnight. After standing overnight, the mixture was centrifuged at 10,000 rpm for 15 min. The supernatant was removed by pipetting, and the precipitate was dried in an oven to constant weight. 1 mL of sterile water was then added to dissolve the precipitate to obtain the γ-PGA test solution. 1 mL of the test solution was added to 1 mL of CTAB (hexadecyltrimethylammonium bromide) solution, and the mixture was shaken thoroughly, avoiding foaming during shaking. After standing at room temperature for 3 minutes, the absorbance of the test solution was measured at 250 nm using a UV spectrophotometer. The concentration of γ-PGA in the fermentation broth was obtained by substituting the absorbance value into the γ-PGA standard curve. The final yield of polyglutamic acid produced by strain H102 was 8.87 µg / mL. Figure 11 Standard curve for determining polyglutamic acid content in Microbacterium acetylcholine H102.

[0087] Example 5: Identification of the growth-promoting function of strain H102

[0088] 1. Seed culture

[0089] Pick a single colony of activated H102 strain with a pipette tip, inoculate it into a 50 mL centrifuge tube containing 10 mL of LB medium with added salt, and incubate overnight in a shaker at 30°C and 200 rpm to obtain seed culture.

[0090] 2. Fermentation culture

[0091] 100 μL of seed culture was inoculated into a 250 mL Erlenmeyer flask containing 100 mL of glucose peptone medium and incubated at 30 °C and 200 rpm for 72 h.

[0092] 3. Greenhouse pot experiments on tomatoes and corn

[0093] Two potted plant experiments were conducted, one with corn and the other with tomatoes. Water served as the control group, while a 10-fold dilution of H102 bacterial solution (bacterial solution concentration 10) was used as the treatment group. 8 ~10 9 (CFU / mL). A completely randomized design was used, with 6 replicates for each treatment. The entire experiment was conducted in an artificial greenhouse. During the experiment, the temperature in the greenhouse was set at (25±3)℃, the relative humidity at 60~70%, and the light intensity at 14 hd. -1 Illuminance 5000 lx.

[0094] The tomato seeds were of the variety "Xinzhongshu No. 4" and were purchased from Hanyu Seed Industry. The soil used for the tomato greenhouse pot experiment was vegetable soil from Yixing City, Jiangsu Province (32°46'12'' N, 120°56'19'' E). After being naturally air-dried, the soil was sieved through a 2 mm sieve and thoroughly mixed before use.

[0095] The corn seeds were of the variety "Huangnuo 688" and were purchased from Gansu Tianfu Agricultural Technology Development Co., Ltd. The soil used for the corn greenhouse pot experiment was moderately saline coastal soil from Yancheng City, Jiangsu Province (32°46'12'' N, 120°56'19'' E, electrical conductivity 722 µs / cm, salinity 0.04%). After natural air drying, the soil was sieved through a 2 mm sieve and thoroughly mixed before use.

[0096] First, tomato and corn seeds were soaked in sterile water for 10 minutes, then a 2% sodium hypochlorite solution was added and shaken thoroughly for 8-10 minutes for surface disinfection. This process was repeated twice. After disinfection, the seeds were soaked in sterile water again for 30 minutes, and then rinsed 8-10 times with sterile water to remove any residual sodium hypochlorite solution. The seeds were then blotted dry with sterile filter paper, and plump, uniformly sized seeds were sown evenly in seedling trays containing experimental soil. After about two weeks of seedling cultivation, uniformly growing seedlings were selected and transplanted into pots. Two tomato seedlings were planted per pot, and four corn seedlings per pot. The pots had a volume of approximately 360 mL (upper and lower bottom inner diameters and height were 90, 60, and 110 mm, respectively), and each pot contained 320 g of well-mixed, air-dried soil. On the second day after transplanting, different treatment solutions (clean water and H102 bacterial solution diluted 10 times with clean water) were applied to the roots of the plants, 10 mL per pot. Routine pot cultivation management was followed.

[0097] Depend on Figure 12 As shown in Table 1, applying H102 bacterial solution to the rhizosphere soil of tomatoes resulted in better growth promotion. Compared with the control group on FJ medium, the plant height, SPAD, leaf area, aboveground dry weight, and underground dry weight of potted tomato seedlings treated with H102 bacterial solution were significantly increased by 28.3%, 11.8%, 109.7%, 111.8%, and 109.7%, respectively.

[0098] Depend on Figure 13 As shown in Table 2, the results of the experiment on corn pot plants also showed that the H102 strain of bacterial solution had a significant growth-promoting effect on the plants, with the plant height and underground dry weight of corn increasing significantly by 2.9% and 114.8%, respectively.

[0099] This indicates that strain H102 can significantly promote the growth of tomato and corn seedlings.

[0100] Table 1. Growth of tomato seedlings

[0101]

[0102] Table 2. Growth of maize seedlings

[0103]

[0104] This invention provides a strain of Microbacterium acetylcholine and its application, along with related ideas and methods. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment of the invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technologies.

Claims

1. A strain of *Exiguobacterium acetylicum*, classified as *Exiguobacterium acetylicum*, with strain number H102, was deposited on December 24, 2025, at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC No. 37157.

2. The application of the Acetylmicrobacterium as described in claim 1 in the fermentation production of acetoin.

3. The application of the Acetylmicrobacterium as described in claim 1 in the fermentation production of polysaccharides.

4. The application of the Acetylmicrobacterium as described in claim 1 in the fermentation production of polyglutamic acid.

5. The application of the Acetylmicrobacterium as described in claim 1 in promoting crop growth.

6. The application of the Acetylmicrobacterium of claim 1 in improving crop tolerance to abiotic stress.

7. The application according to claim 5 or 6, characterized in that, The crop is tomato and / or corn.

8. The application according to claim 6, characterized in that, The abiotic stresses include any one or a combination of several of the following: salinity stress, drought stress, and high temperature stress.

9. A microbial growth promoter, characterized in that, Fermentation broth containing the acetylmicrobacterium described in claim 1.

10. The microbial growth promoter according to claim 9, characterized in that, The concentration of the fermentation broth is 10. 5 ~10 11 CFU / mL.

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