Exiguobacterium basophilus, microbial inoculum and application of microbial inoculum

Abstract

The invention provides an Exiguobacterium basophilus, a microbial agent and application of the Exiguobacterium basophilus, the Exiguobacterium basophilus strain S112 is preserved in the China General Microbiological Culture Collection Center (CGMCC) on November 12, 2025, and the preservation number is CGMCC No.36581. The invention further provides a preparation method of the Exiguobacterium basophilus strain S112. The Exiguobacterium basophilus and the microbial agent provided by the invention can synchronously remove various pollutants including phosphorus, heavy metal hexavalent chromium, blue-green algae and the like in a water body, have the advantages of ecological safety, efficient synergy, wide adaptability and the like, and provide new microbial resources and technical schemes for water pollution treatment.

Description

Technical Field

[0001] This invention relates to the fields of microbial technology and water pollution control technology, and in particular to an alkalophilic microbacterium, a bacterial agent, and its application. Background Technology

[0002] With the acceleration of global industrialization and urbanization, and the large-scale development of agricultural production, large amounts of industrial and agricultural wastewater, domestic sewage, and agricultural runoff containing nutrients such as nitrogen and phosphorus are discharged directly into natural water bodies without effective treatment, leading to an increasingly serious eutrophication problem worldwide. According to the "2024 China Ecological Environment Status Bulletin," more than 15% of monitoring sections of surface water in my country are still in a eutrophic state, with lakes and reservoirs reaching over 25%. In eutrophic waters, phosphorus, as a limiting nutrient for algal growth, can directly trigger cyanobacterial blooms due to its excessive accumulation. Common cyanobacteria that cause these blooms include *Aphanizmenon*, *Cylindrospermopsis*, *Dolichosperma*, *Microcystis*, *Nodularia*, *Planktothrix*, and *Trichodesmium*. Cyanobacterial blooms cause decreased water transparency, reduced dissolved oxygen levels, aquatic organism mortality, water quality deterioration, and the emission of pungent odors. Furthermore, some cyanobacterial blooms release toxins that can cause liver, digestive, and nervous system diseases when ingested by birds, mammals, and humans. Therefore, cyanobacterial blooms not only disrupt the ecological balance and reduce biodiversity, but also affect drinking water safety and landscape value, posing a serious challenge to regional sustainable economic and social development and ecological environmental protection.

[0003] Meanwhile, hexavalent chromium (Cr(VI)), a highly toxic and persistent heavy metal pollutant, is widely present in wastewater from industries such as electroplating, leather tanning, and chemical processing. It enters the aquatic environment through discharge, posing a serious threat to aquatic ecosystems and public health. Cr(VI) is highly carcinogenic, genotoxic, and mutagenic, and is difficult to degrade under natural conditions, tending to accumulate persistently in the environment, further exacerbating its ecological and health risks.

[0004] To address these issues, various remediation technologies have been developed both domestically and internationally, primarily falling into three categories: physical, chemical, and biological methods. However, these traditional technologies all have limitations in practical application. Physical methods mainly include mechanical dredging, water diversion for silt flushing, bottom sediment dredging, and aeration. However, these methods generally suffer from high costs, complex operations, and short-lived effects, making large-scale application difficult. Chemical methods mainly involve adding chemical agents (such as CuSO4 and H2O2) to the water to kill algae or precipitate phosphates. However, the use of chemical agents may damage the structure and function of the ecosystem and may harm human health through the food chain. Furthermore, the use of chemical agents can cause drastic changes in water pH, leading to secondary pollution. Therefore, the application of chemical methods is increasingly restricted, especially in drinking water sources and ecologically sensitive areas.

[0005] Biological methods are considered the most promising water environment management technologies, mainly involving ecological restoration using aquatic plants, aquatic animals, and microorganisms. Aquatic plants (such as submerged plants) can inhibit algal growth through nutrient absorption and allelopathic effects, but their long growth cycle makes them susceptible to environmental limitations, and they struggle to survive in water bodies with severe algal blooms. Aquatic animals (such as filter-feeding fish) can control algal biomass by consuming algae, but their algal control effect is unstable and may alter the original food web structure of the water body. In contrast, microorganisms have become a research hotspot both domestically and internationally due to their advantages such as rapid reproduction, strong adaptability, flexible application, and eco-friendliness. However, existing microbial agents still suffer from limited functionality, making it difficult to simultaneously address the combined pollution of eutrophication and algal blooms; while compound microbial agents, although multifunctional, face challenges such as interspecies competition, complex processes, increased costs, and insufficient stability of efficacy.

[0006] Therefore, screening for multifunctional, highly efficient, and environmentally adaptable single bacterial strains that can remove pollutants from water and control cyanobacterial blooms, and developing corresponding low-cost, highly stable bacterial agents and application technologies, is of great practical significance and application value for solving water pollution problems. Summary of the Invention

[0007] In view of this, the present invention proposes a strain of alkalophilic microbacterium, a microbial agent and its application. The alkalophilic microbacterium strain S112 provided by the present invention can simultaneously achieve the dual effects of removing water pollutants and inhibiting the growth of cyanobacteria blooms through its own metabolic activities. It effectively overcomes the shortcomings of existing technologies, such as the limited treatment effect of single-function microbial agents and the high cost and complex process of compound microbial agents. It provides a brand-new microbial resource and technical solution for achieving low-cost, ecologically safe and comprehensive treatment of water pollution.

[0008] The technical solution of this invention is implemented as follows: In a first aspect, the present invention provides a strain of alkalophilic microbacterium, namely strain S112, which was deposited on November 12, 2025 at the China General Microbiological Culture Collection Center (CGMCC) with accession number CGMCC No. 36581.

[0009] Based on the above technical solutions, the 16S rRNA sequence of the alkalophilic microbacterium is further shown in SEQ ID NO.1.

[0010] The *Microbacterium alkalophilum* strain described in this invention was isolated from the soil of the eutrophic Nanhu Lake ecotone in Wuhan, China (coordinates: 30°30′20.88″N, 114°21′23.4″E). Systematic identification revealed its 16S rRNA gene sequence to be shown in SEQ ID NO:1, and scanning electron microscopy showed its cell morphology to be regular rod-shaped. This strain exhibits rapid proliferation and excellent environmental adaptability, while also possessing multiple biological activities, including highly efficient removal of pollutants from water and significant inhibition of cyanobacteria blooms such as *Microcystis aeruginosa*, thus overcoming the bottleneck of existing functional strains with limited single-function applications.

[0011] Secondly, the present invention provides a microbial inoculant containing the aforementioned alkalophilic microbacterium.

[0012] Based on the above technical solutions, the microbial agent can be further prepared into various dosage forms such as liquid, solid, or lyophilized powder.

[0013] The microbial agent has the characteristics of high viable count, good storage stability, and convenient application, which can meet the needs of different application scenarios.

[0014] Thirdly, the present invention provides the application of the aforementioned alkalophilic microbacteria and microbial agents in the remediation of eutrophic water bodies, control of cyanobacterial blooms, and wastewater treatment, and is applied to inhibit cyanobacterial growth and remove chromium and / or phosphorus.

[0015] Based on the above technical solution, the alkalophilic microorganisms or microbial agents are further added to the water body to be remediated, so that the final concentration of alkalophilic microorganisms is 10. 6 ~10 10 CFU / L.

[0016] Based on the above technical solutions, the cyanobacteria further include at least one of Microcystis aeruginosa, Anabaena aeruginosa, Fibrocystis aeruginosa, Synechocystis aeruginosa, Oscillatoria aeruginosa, and Nostoc commune.

[0017] It should be noted that this invention specifically addresses the technical challenges of "simultaneous phosphorus reduction, algae removal, and chromium removal" in actual polluted water bodies: Regarding the inhibition of microorganisms by the strong toxicity of hexavalent chromium, the alkalophilic microbacterium strain S112 of this invention originates from soil surrounding eutrophic polluted water bodies and has developed excellent chromium tolerance through natural environmental acclimatization. Its metabolic system is not easily affected by Cr(VI) toxicity, allowing it to proliferate and function normally in chromium-containing water bodies. Regarding the mutual interference between phosphorus, cyanobacterial metabolites, and chromium removal, this strain, through its own synergistic metabolic mechanism, efficiently absorbs and transforms phosphorus while secreting algae-inhibiting substances to inhibit cyanobacterial growth. Furthermore, the above metabolic process does not alter key microenvironmental parameters of the water body; instead, it provides suitable conditions for the reduction and removal of chromium, breaking the vicious cycle of "toxicity inhibition - functional failure - mutually exclusive effects." Compared to existing single-function bacterial agents that require multiple additions and compound bacterial agents that suffer from bacterial antagonism, this invention achieves triple efficacy through a single bacterial strain, eliminating the need for compounding with other bacterial strains or agents. This simplifies the application process, reduces treatment costs, and avoids the problem of unstable effects caused by bacterial competition, perfectly meeting the treatment needs of actual complex polluted water bodies.

[0018] Compared with the prior art, the present invention has the following beneficial effects: (1) The alkalophilic microbacterium provided by the present invention can simultaneously achieve efficient "chromium removal", "phosphorus reduction" and "algae removal", solving the problem of instability of multiple bacterial agents and simplifying the application process.

[0019] (2) The alkalophilic microbacterium provided by the present invention can inhibit Microcystis aeruginosa by more than 85% within 7 days, remove more than 90% of total phosphorus, and remove more than 90% of heavy metal chromium. It has a fast onset of action and high treatment efficiency.

[0020] (3) The present invention adopts a pure biological treatment method, which avoids the risk of secondary pollution caused by chemical agents and has good environmental compatibility.

[0021] (4) The alkalophilic microbacterium strain provided by the present invention is derived from the natural water environment, has good adaptability to actual water conditions, and exhibits broad-spectrum algae-inhibiting activity in a variety of cyanobacteria coexisting systems, and has a wide range of applications. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a typical colony morphology diagram of the alkalophilic microbacterium strain S112 provided by this invention on a solid plate culture medium; Figure 2 This is a three-dimensional morphological characterization image of the alkalophilic microbacterium strain S112 provided by the present invention using scanning electron microscopy (SEM). Figure 3 It is a phylogenetic tree constructed based on the 16S rRNA gene sequence; Figure 4 This is a graph showing the total phosphorus removal effect and cyanobacterial inhibition effect of the alkalophilic microbacterium strain S112 provided by this invention under actual natural water conditions. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] In the following specific embodiments, Microcystis aeruginosa (FACHB905), Anabaena sp. (FACHB82), Aphanizomenon sp. (FACHB1395), Synechocystis sp. (PCC6803), Oscillatoria sp. (FACHB528), and Nostoc sp. (FACHB892) were all purchased from the Institute of Hydrobiology, Chinese Academy of Sciences.

[0026] In the following specific implementation method, the cultivation method of cyanobacteria such as Microcystis aeruginosa is as follows: Microcystis aeruginosa is placed at 25°C with a light intensity of 40 μE·m. -2 ·s -1 In an artificial climate incubator with a light-dark cycle ratio of 12 h (light):12 h (dark), all cyanobacteria were cultured on BG11 medium. The initial cell density of the algal solution was approximately 0.5 × 10⁻⁶ cells / day. 8 -1×10 8 The algal cell count / L meets the requirements for moderate cyanobacterial blooms (DB5301 / T 56-2021 Kunming Municipal Local Standard for Grading, Early Warning and Emergency Treatment of Cyanobacterial Blooms in Dianchi Lake).

[0027] In the following specific embodiments, the preparation process of LB liquid culture medium is as follows: Weigh 5 g NaCl, 10 g tryptone, and 5 g yeast extract, add 1 L deionized water, adjust the pH to 7.0-7.2, and sterilize at high temperature before use. For solid culture medium, add 15 g agar powder to the liquid culture medium, sterilize at high temperature, and set aside.

[0028] In the following specific embodiment, *Exiguobacterium alkaliphilum* strain S112 was isolated from the soil surrounding Nanhu Lake, a eutrophic water body in Wuhan, China (30°30′20.88″N, 114°21′23.4″E) on June 30, 2025. It was deposited on November 12, 2025, at the China General Microbiological Culture Collection Center (CGMCC, address: No. 3, No. 1, Beichen West Road, Chaoyang District, Beijing), with accession number CGMCC No. 36581, and its microbiological classification name is *Exiguobacterium alkaliphilum*.

[0029] Example 1 This embodiment provides the screening, isolation, and identification of alkalophilic microbacterium strain S112, including the following steps: (1) Weigh 10 g of the collected soil sample and place it in a 250 mL conical flask. Add 90 mL of sterile water and place it in a shaker at 100 rpm and 30 °C for 1 h to obtain a soil mixture.

[0030] (2) Take 1 mL of soil mixture and dilute it to 10, 100, 1000 and 10000 times. Take 100 μL of each dilution and spread it on the isolation medium plate. Incubate in a constant temperature incubator at 30℃ for 48 h. Pick a single colony and further purify it by streaking the plate multiple times until a single colony is obtained. Then, transfer it to liquid medium for expansion culture.

[0031] (3) The cell morphology of strain S112 was observed using a scanning electron microscope.

[0032] (4) Determine the 16S rRNA gene sequence of strain Strain S112 for species identification. The genome of strain Strain S112 was extracted, and PCR amplification of the 16S rRNA was performed using universal primers 27F (5-AGAGTTTGATCCTGGCTCAG-3) and 27R (5-GGTTACCTTGTTACGACTT-3). The PCR products were detected by agarose gel electrophoresis and then recovered for sequencing. The sequenced sequences were compared with those obtained from NCBI (https: / / www.ncbi.nlm.nih.gov / ), and the sequence with the highest similarity and the highest overall score was selected as the species identification result.

[0033] The colonies of strain S112 on solid culture medium have smooth, moist surfaces and are pale yellow in color. Figure 1 As shown. Figure 2 As shown, strain S112 has a short rod-shaped morphology.

[0034] The 16S rRNA gene sequence of strain strain S112 was analyzed, and the gene sequence of the strain is shown in SEQ ID NO.1.

[0035] By comparing gene sequences with those in the NCBI database, it was found that the 16S rRNA gene (SEQ ID NO.1) of strain S112 had the highest sequence similarity (99.65%) with that of Exiguobacterium alkaliphilum 12 / 1.

[0036] A phylogenetic tree was constructed using the 16S rRNA sequence of strain S112. For example... Figure 3 As shown in the phylogenetic tree, strain S112 and Exiguobacterium alkaliphilum cluster together, further indicating that strain S112 and Exiguobacterium alkaliphilum are most closely related.

[0037] Therefore, strain S112 was classified as *Exiguobacterium alkaliphilum*.

[0038] Example 2 This embodiment provides a microbial inoculum containing *Microbacterium alkalophilum* strain S112 and its preparation method. The microbial inoculum includes liquid, solid, and lyophilized powder formulations.

[0039] The preparation method of the liquid dosage form includes: fermenting and culturing *Microbacterium alkalophilum* strain S112 to the late logarithmic stage, adding a protectant (glycerol), and then dispensing.

[0040] The preparation method of solid dosage form includes: centrifuging the fermentation broth to obtain high concentration of bacterial cells, then uniformly adsorbing and mixing it with a sterilized carrier (diatomaceous earth), and finally drying it at low temperature, pulverizing and sieving it to make powder.

[0041] The preparation method of the freeze-dried powder formulation includes: mixing concentrated bacterial cells with a compound freeze-drying protectant (trehalose), and then undergoing a deep pre-freezing and freeze-drying process to completely remove moisture and obtain a highly active loose powder.

[0042] Example 3 This embodiment compares the effects of different components of *Strain S112* (bacterial culture medium, sterile supernatant, and bacterial suspension) on the growth of *Microcystis aeruginosa*. The steps include: 1. Incubate *Microbacterium alkalophilum* strain S112 at 30°C and 100 rpm with constant temperature shaking until OD. 600 A value of 1.0–1.4 indicates that the bacterial culture medium is in the late logarithmic growth stage. 2. The above bacterial culture medium was treated as follows, with three treatment groups: bacterial culture medium, sterile supernatant, and bacterial suspension: (1) The bacterial culture medium was used directly as a group; (2) After centrifugation, the supernatant of the bacterial culture medium is filtered through a 0.22 μm filter membrane to obtain a sterile supernatant; (3) The bacterial precipitate after centrifugation is resuspended in sterile water to prepare a bacterial suspension; Each of the above samples was inoculated into Microcystis aeruginosa solution at an inoculation rate of 10% (V / V). After culturing for 9 days, the chlorophyll a content in each group of algal solutions was measured, and the algal inhibition rate was calculated.

[0043] The results are shown in Table 1. The chlorophyll a content of the algal solution in the bacterial culture medium treatment group was significantly lower than that in other treatment groups, indicating that it had the best inhibitory effect on Microcystis aeruginosa; the bacterial suspension treatment group was the second best, while the sterile supernatant treatment group had the lowest inhibitory effect.

[0044] Table 1. Inhibitory effects of different components of *Microcystis alkalophilus* strain S112 on *Microcystis aeruginosa*.

[0045] Example 4 This embodiment compares the inhibitory effect of alkalophilic microbacterium strain S112 on Microcystis aeruginosa under different treatment times, including the following steps: The bacterial culture medium in the late logarithmic growth stage was divided into 10... 8 An inoculum of CFU / L was added to the Microcystis aeruginosa solution, and samples were taken on days 1, 3, 5, 7, and 9 after treatment to determine the chlorophyll a content in the algal solution at each time point and calculate the algal inhibition rate.

[0046] The results are shown in Table 2. With increasing treatment time, the chlorophyll a content in the algal solution decreased significantly, indicating that StrainS112 has a sustained inhibitory effect on Microcystis aeruginosa. By day 7 of treatment, most algal cells had been effectively inhibited, demonstrating that this strain has a rapid and efficient treatment capacity in controlling the proliferation of Microcystis aeruginosa in eutrophic waters.

[0047] Table 2. Inhibitory effect of alkalophilic microbacterium strain S112 on the dominant algal bloom species Microcystis aeruginosa.FACHB905

[0048] Example 5 This embodiment provides the inhibitory effect of *Microbacterium alkalophilum* strain S112 on other toxin-producing cyanobacteria, including *Anabaena* sp. *FACHB82*, *Aphanizomenon* sp. *FACHB1395*, *Oscillatoria* sp. *FACHB528*, and *Nostoc* sp. *FACHB892*. The steps include: The bacterial culture medium in the mid-to-late logarithmic growth stage was divided into 10... 6 An inoculum of CFU / L was added to algal solutions containing different algae. After culturing for 7 days, the chlorophyll a content of different algae was measured, and the algal inhibition rate was calculated.

[0049] The results are shown in Table 3. The alkalophilic microbacterium strain S112 showed significant inhibitory effects on Anabaena, Thymicola, Oscillatoria and Nostoc, with inhibition rates all exceeding 80%. This indicates that the strain has a broad-spectrum and highly efficient algal inhibitory ability against a variety of toxin-producing cyanobacteria, and has good application potential in controlling the proliferation of harmful cyanobacteria in water bodies.

[0050] Table 3. Inhibitory effects of alkalophilic microbacterium strain S112 on different toxin-producing cyanobacteria.

[0051] Example 6 This embodiment evaluated the phosphorus removal capacity of the alkalophilic microbacterium strain S112 in the aquatic environment. The specific implementation steps are as follows: The bacterial culture medium in the late logarithmic growth stage was centrifuged at 8000-12000 rpm for 2-5 min, the bacterial cells were collected, washed with sterile water and resuspended to prepare a bacterial suspension. This bacterial suspension was then centrifuged at 10... 10 The solution was inoculated into water with an initial phosphorus concentration of 20 mg / L at a concentration of CFU / L. An equal volume of sterile water was used as a blank control. The inoculated system was then cultured with shaking at 37°C and 150 rpm.

[0052] Total phosphorus content in water samples was determined using the ammonium molybdate spectrophotometric method. Various phosphorus compounds were converted into orthophosphates; in an acidic environment, the orthophosphates reacted with ammonium molybdate to form phosphomolybdic heteropolyacid in the presence of antimony salts, which was subsequently reduced by ascorbic acid to a blue complex. This blue complex exhibited maximum absorbance at 700 nm. Total phosphorus content (x) and OD... 700 The standard curve equation between nm values ​​(y) is: y = 0.0233x - 0.0035, with a correlation coefficient R. 2 =0.9989.

[0053] The total phosphorus content in the inoculated culture medium and the uninoculated control were determined by the above method, and the removal rate of total phosphorus by *Microbacterium alkalophilum* strain S112 in a system with an initial phosphorus content of 20 mg / L was calculated.

[0054] The results are shown in Table 4. After 7 days of treatment with alkalophilic microbacterium strain S112, the experimental group was able to remove more than 90% of the phosphorus in the system, indicating that the strain has a high phosphorus removal capacity and has good application potential in the remediation of eutrophic water bodies and the control of phosphorus pollution.

[0055] Table 4. Phosphorus removal efficiency of *Microbacterium alkalophilum* strain S112

[0056] Example 7 This embodiment evaluated the removal capacity of the alkalophilic microbacterium strain S112 for chromium in the aquatic environment. The specific steps are as follows: Calculate the alkalophilic microbacterium strain S112 at 10 8 The strain was inoculated into synthetic wastewater with an initial hexavalent chromium concentration of 100 mg / L at a ratio of CFU / L. The wastewater was cultured with shaking at 30°C and 120 rpm, and samples were taken on days 1, 3, 5, 7, and 9 to determine the residual concentration of hexavalent chromium and to evaluate the removal efficiency of the strain for hexavalent chromium.

[0057] The concentration of hexavalent chromium in water samples was determined using the "Determination of Hexavalent Chromium in Water - Diphenylcarbazide Spectrophotometric Method" (GB / T 7467-87). The removal efficiency of the alkalophilic microbacterium strain S112 in synthetic wastewater with an initial hexavalent chromium concentration of 100 mg / L was calculated.

[0058] The results are shown in Table 5. After 7 days of treatment with alkalophilic microbacterium strain S112, the removal rate of hexavalent chromium in the synthetic wastewater reached over 90%, proving that this strain has a highly efficient removal capacity for hexavalent chromium in water.

[0059] Table 5. Removal efficiency of hexavalent chromium by *Microbacterium alkalophilum* strain S112

[0060] Example 8 This embodiment evaluated the comprehensive remediation effect of *Microbacterium alkalophilum* strain S112 in eutrophic natural water bodies, testing its ability to remove total phosphorus and its inhibitory effect on algal growth. The steps included are as follows: The culture medium of *Microbacterium alkalophilum* strain S112 in the late logarithmic growth stage was centrifuged to collect the bacterial cells, washed with sterile water and resuspended to prepare a high-concentration bacterial suspension. This bacterial suspension was then subjected to a 10⁻⁶... 8 The final concentration of CFU / L was inoculated into natural water samples collected from eutrophic lakes. All treatment groups were placed under suitable light and temperature conditions and cultured using static or gentle shaking methods.

[0061] The total phosphorus content in the water sample was determined using the ammonium molybdate spectrophotometric method described in Example 6, and the total phosphorus removal rate was calculated. Chlorophyll a content was simultaneously measured to characterize changes in algal biomass in the water sample, and the algal inhibition rate was calculated.

[0062] The results are as follows Figure 4 As shown, after 7 days of treatment with *Microbacterium alkalophilum* strain S112, the total phosphorus content in the water sample decreased significantly, with a removal rate exceeding 90%. Simultaneously, the chlorophyll a content in the water sample decreased significantly, and the algae inhibition rate reached over 85%. These results indicate that *Microbacterium alkalophilum* strain S112 can simultaneously and efficiently remove phosphorus nutrients from water bodies and inhibit algal proliferation, demonstrating a dual function of synergistic phosphorus removal and algae inhibition in the remediation of eutrophic natural water bodies, and possessing significant environmental application value.

[0063] Example 9 This embodiment evaluated the removal efficiency of *Microbacterium alkalophilum* strain S112 in polluted water containing hexavalent chromium, total phosphorus, and algae, testing its removal capacity for hexavalent chromium and total phosphorus, as well as its inhibitory effect on algal growth. The process included the following steps: Take 1L of natural water sample collected from the eutrophic lake area in Example 8, add hexavalent chromium to a final concentration of 100mg / L to obtain the water sample to be tested.

[0064] The culture medium of *Microbacterium alkalophilum* strain S112 in the late logarithmic growth stage was centrifuged to collect the bacterial cells, washed with sterile water and resuspended to prepare a high-concentration bacterial suspension. This bacterial suspension was then subjected to a 10⁻⁶... 8 The final concentration of CFU / L was inoculated into the water sample to be tested. The sample was then incubated with shaking at 30°C and 120 rpm for 7 days.

[0065] The total phosphorus content in the water sample was determined using the ammonium molybdate spectrophotometric method described in Example 6, and the total phosphorus removal rate was calculated. Chlorophyll a content was simultaneously measured to characterize changes in algal biomass in the water sample, and the algal inhibition rate was calculated. The concentration of hexavalent chromium in the water sample was determined using the diphenylcarbazide spectrophotometric method described in Example 7 (GB / T 7467-87 Water Quality - Determination of Hexavalent Chromium).

[0066] The results are shown in Table 6. After 7 days of treatment with *Microbacterium alkalophilum* strain S112, the total phosphorus content in the water samples decreased significantly, with a total phosphorus removal rate of over 85%. Simultaneously, the chlorophyll a content in the water samples decreased significantly, and the algae inhibition rate reached over 85%. The removal rate of hexavalent chromium reached over 80%.

[0067] Table 6. Removal efficiency of hexavalent chromium and total phosphorus and algal inhibition rate of *Microbacterium alkalophilum* strain S112.

[0068] Comparative Example 1 The strain Rhodotorula mucilaginosa TLJ-1 (accession number: GDMCC No: 64271) disclosed in invention patent CN119120233A and the strain Bacillus sp. L1-3 (accession number: CCTCC N) disclosed in invention patent CN120384021A were used. O Compared with M 2025629, although the strains with algicidal function disclosed in the prior art have algicidal ability to a certain extent, they all lack efficient and stable phosphorus reduction and chromium removal functions, and cannot achieve the treatment goal of simultaneously reducing phosphorus, inhibiting algae and removing chromium.

[0069] The results are shown in Table 7. In comparison, the alkalophilic microbacterium (Exiguobacterium alkaliphilum strain S112) provided by this invention simultaneously achieved efficient removal of total phosphorus (removal rate > 90%), broad-spectrum inhibition of various cyanobacteria (algal inhibition rate > 85%), and efficient removal of hexavalent chromium (removal rate > 90%) in the same system, demonstrating significant functional synergy and ecological restoration potential. It is suitable for the comprehensive treatment of eutrophic water bodies, cyanobacterial blooms, and the heavy metal hexavalent chromium.

[0070] Table 7 Summary and comparison of the strains of this invention with the comparative strains

[0071] In summary, this invention proposes an alkaline-loving microbacterium, a microbial agent, and their applications. The alkaline-loving microbacterium strain S112 provided by this invention can simultaneously achieve the dual effects of removing water pollutants and inhibiting the growth of cyanobacteria blooms through its own metabolic activities. It effectively overcomes the shortcomings of existing technologies, such as the limited treatment effect of single-function microbial agents and the high cost and complex process of compound microbial agents. This invention provides a brand-new microbial resource and technical solution for achieving low-cost, ecologically safe, and comprehensive treatment of water pollution.

[0072] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An Alcaligenes parvus, characterized in that, The alkaliphilic Parvibacter is Parvibacter alkalitolerans strain S112, which has been preserved in the China General Microbiological Culture Collection Center on November 12, 2025, and the preservation number is CGMCC No. 36581.

2. The Alcaligenes microorganism of claim 1, wherein The 16sRNA sequence of the alkaliphilic Parvibacter is shown as SEQ ID NO.

1.

3. A microbial inoculant, characterized in that, The alkaliphilic Parvibacter according to any one of claims 1-2.

4. The application of Alkalimicrobium bicolor or the microbial inoculant of claim 3 in the restoration of eutrophic water bodies, the control of cyanobacterial blooms, and the treatment of sewage, characterized in that, It is applied to inhibit the growth of blue algae, remove hexavalent chromium and / or phosphorus.

5. The use according to claim 4, wherein the compound is ###0002### The blue algae include at least one of Microcystis aeruginosa, Anabaena, Comsphaerophorum, Synechococcus, Oscillatoria and Nostoc. The blue algae include at least one of Microcystis aeruginosa, Anabaena, Comsphaerophorum, Synechococcus, Oscillatoria and Nostoc.

6. The use according to claim 4, wherein the compound is ###0002### The alkaliophilic microbacterium or microbial inoculant is added to the water body to be restored, so that the final concentration of alkaliophilic microbacterium is 10 6 ~10 10 CFU / L.

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