Xiamen shewanella and application thereof

Abstract

The invention relates to shewanella xiamenensis and application thereof. The Xiamenensis shewanella is obtained through ion mutagenesis, the strain name is Xiamenensis shewanella CQ-T200, the preservation unit is China Center for Type Culture Collection, the preservation address is Wuhan University, Wuhan, China, the preservation number is CCTCC NO: M 20252555, and the preservation date is November 17, 2025. The strain can be used for producing the blue iron ore by using Fe (III), has the advantages of simplicity in operation, low cost, high yield of the blue iron ore, short production time and the like, and provides a simple and economical fermentation process for producing the blue iron ore by microbial fermentation.

Description

Technical Field

[0001] This invention belongs to the field of microbial fermentation technology, and in particular relates to a strain of Shewanella xiaensis and its application. Background Technology

[0002] Azurite is a phosphorus-rich mineral with significant applications in agriculture, considered a highly efficient slow-release fertilizer. This fertilizer effectively improves crop nutrient absorption, thus reducing the overuse of chemical fertilizers. Compared to traditional calcium phosphate, azurite demonstrates superior performance in promoting crop growth, particularly showing significant yield increases in legume cultivation, making it an ideal alternative to traditional fertilizers. In the industrial sector, azurite is also a key precursor in the production of lithium iron phosphate batteries, playing a crucial role in lithium battery manufacturing. Currently, in the phosphate product market, the unit price of azurite is significantly higher than that of ordinary phosphate rock and other phosphates, giving it high economic value.

[0003] In the synthesis of lapis lazuli, microbial-induced mineralization technology has attracted widespread attention due to its environmental friendliness and process feasibility. This process typically constructs an iron-phosphorus complex system under anaerobic conditions, utilizing the metabolic activity of dissimilar metal-reducing bacteria to reduce ferric iron to ferrous iron, which then combines with phosphate ions in the system to form lapis lazuli precipitate. Compared to other processes, the microbial method has significant advantages in terms of reaction condition control and reaction cost. For example, the magnesium ammonium phosphate crystallization method requires high pH conditions (pH > 8.5) and has high magnesium salt costs, while the calcium hydroxyphosphate crystallization method is easily affected by calcium carbonate byproducts, resulting in low product purity and phosphorus recovery.

[0004] Although microorganisms can mediate the formation of vivianite, the formation rate is still limited by the metabolic activity and electron transfer efficiency of the strain, resulting in a relatively long overall reaction cycle. For example, iron-reducing bacteria... Shewanella oneidensis MR-4 can use hydrated iron oxide as an electron acceptor to gradually form lapis lazuli in the extracellular space, but this process is time-consuming, requiring approximately 16 days of culture before lapis lazuli crystals begin to appear (Wang Fuxian, Zheng Shiling, Qiu Hao, et al. Iron-reducing bacteria). Shewanella oneidensis The process of MR-4-induced formation of lapis lazuli from hydrated iron oxide [J]. Acta Microbiologica Sinica, 2018, 58(4):573-583. DOI:10.13343 / j.cnki.wsxb.20180029.). Shewanella putrefactive bacteria ( Shewanella putrefaciensCN32 can also generate vivianite during the reduction of α-FeOOH, but a reaction time of 15 days is still required (Li, H., Cao, W., Wang, W., Huang, Y., Xiang, M., Wang, C., Chen, S., Si, R., & Huang, M. (2021). Carbon nanotubes mediating nano α-FeOOH reduction by Shewanella putrefaciensCN32 to enhance tetrabromobisphenol A removal. The Science of the totalenvironment, 777, 146183. https: / / doi.org / 10.1016 / j.scitotenv.2021.146183). Therefore, finding suitable microorganisms to accelerate the bio-production of vivianite is key to promoting its practical application. Summary of the Invention

[0005] In view of the problems existing in the prior art, the present invention provides a strain of Shewanella xiaensis and its application in the production of vivianite. The production of vivianite using Shewanella xiaensis has advantages such as simple operation, low cost, high purity of vivianite, and short production time. The strain provided by the present invention can be widely used in the production of vivianite and has good market potential.

[0006] The technical solution of the present invention to solve the above-mentioned technical problems is as follows:

[0007] This invention provides a strain of Shewanella xiaensis, the strain name being Shewanella xiaensis (… Shewanella xiamenensis CQ-T200 has been deposited at the China Center for Type Culture Collection (CCTCC) with accession number CCTCC NO:M 20252555, deposit date November 17, 2025, and deposit address Wuhan University, Wuhan, China.

[0008] The Xiamen Shewanella bacteria were obtained through... It is obtained by ion mutagenesis and can be used to synthesize lapis lazuli using Fe(III). It has the advantages of simple cultivation, easy growth, genetic stability, short time to obtain lapis lazuli, and good application prospects.

[0009] The present invention provides a microbial agent comprising the above-mentioned Shewanella xiaensis or the fermentation broth of the above-mentioned Shewanella xiaensis.

[0010] The present invention provides a method for preparing the above-mentioned bacterial agent, comprising the following steps: fermenting and culturing the above-mentioned Shewanella xiaensis.

[0011] This invention does not impose any particular limitation on the dosage form of the microbial agent; it can be any conventional dosage form in the art, such as liquid, solid, or other dosage forms. In addition to *Shewanella xiaensis*, the microbial agent may also include commonly used components in the art for preparing microbial agents.

[0012] Further, the process may include the following steps: inoculating the above-mentioned *Shewanella xiaensis* into LB liquid medium and culturing at 30°C for 24 h to obtain a seed culture. The seed culture can be used as a microbial agent for the production of vivianite.

[0013] This invention provides the application of the above-mentioned *Shewanella simonii* and / or the above-mentioned bacterial agent in the production of vivianite.

[0014] This invention provides a method for producing lapis lazuli, using the above-mentioned *Shewanella simonii* or the above-mentioned bacterial agent to produce lapis lazuli.

[0015] Furthermore, the above-mentioned strains or inoculants can be added to a fermentation medium with Fe... 3+ Using it as a substrate, fermentation culture is carried out to produce vivianite.

[0016] The present invention provides Xiamen Shewanella ( Shewanella xiamenensis CQ-T200 can produce lapis lazuli by fermentation using Fe(OH)3. This method has the advantages of being inexpensive and readily available, simple to operate, low cost, short production time, and high purity of lapis lazuli, providing a simple and economical fermentation process for the industrialization of microbial mineralization production of lapis lazuli.

[0017] Furthermore, the inoculation dose is 1%-20%. Preferably, the inoculation dose is 10%.

[0018] Furthermore, the initial pH of the fermentation medium is 3-9. Preferably, the pH is 7.

[0019] Furthermore, the fermentation medium contains sodium lactate at a concentration of 1-4 g / L. Preferably, the sodium lactate concentration is 3 g / L.

[0020] Furthermore, the fermentation medium contains ammonium chloride at a concentration of 0.5-2 g / L. Preferably, the ammonium chloride concentration is 1 g / L.

[0021] Furthermore, the fermentation medium also contains hydrogen phosphate ions.

[0022] Furthermore, the fermentation medium also includes 3 g / L KH2PO4, 12.8 g / L Na2HPO4·7H2O, and 2 g / L yeast extract.

[0023] Furthermore, the fermentation culture temperature was 30℃.

[0024] Furthermore, the fermentation time was 48 hours.

[0025] Furthermore, the above-mentioned *Shewanella xiaensis* or the aforementioned inoculum was inoculated into the fermentation medium, and Fe was added. 3+ The solution contains Fe 3+ The volume ratio of the solution to the fermentation medium was 10%, and fermentation was carried out.

[0026] Adopting the above conditions is conducive to further increasing the production of vivianite. Attached Figure Description

[0027] Figure 1 The colony morphology of Shewanella xiaensis CQ-T200 on LB medium.

[0028] Figure 2 TEM image of Shewanella xiaensis CQ-T200.

[0029] Figure 3 It is blue iron ore produced by fermentation of Shewanella ovalis CQ-T200 in Xiamen. Detailed Implementation

[0030] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0031] The present invention provides Xiamen Shewanella ( Shewanella xiamenensis CQ-T200, deposited at: China Center for Type Culture Collection (CCTCC), deposited at: Wuhan University, Wuhan, China, accession number: CCTCC NO: M20252555, deposited on: November 17, 2025.

[0032] The Xiamen Shewanella CQ-T200 provided by this invention is based on Shewanella ( Shewanella xiamenensis CQ-Y1 is the starting bacteria. The strain was obtained through ion-induced mutagenesis and screening. The aforementioned *Shewanella xiaensis* CQ-T200 can be used to produce vivianite through fermentation.

[0033] This invention provides a method for producing vivianite, comprising the following steps:

[0034] (1) Preparation of CQ-T200 seed culture includes the following steps: inoculate Xiamen Shewanella CQ-T200 into LB liquid medium and culture at 30℃ and 120 rpm to obtain CQ-T200 seed culture in the logarithmic phase.

[0035] (2) Inoculate the CQ-T200 seed culture into the fermentation medium at an inoculation amount of 1%-20% (i.e., the volume percentage of CQ-T200 seed culture to fermentation medium is 1%-20%). Add Fe(OH)3 solution to the fermentation medium, with the volume percentage of Fe(OH)3 solution to fermentation medium being 10%. Incubate at 30℃ for 48 h to obtain the product, which is lapis lazuli.

[0036] The fermentation medium formula includes: per 1 L of distilled water, 3 g KH2PO4, 12.8 g Na2HPO4·7H2O, 0.5-2 g NH4Cl, 1-4 g sodium lactate, and 2 g yeast extract, with a pH value of 3-9.

[0037] Further optimization of conditions such as sodium lactate concentration, ammonium chloride concentration, initial pH of fermentation medium, and inoculum size revealed that when the sodium lactate concentration was 3 g / L, the ammonium chloride concentration was 1 g / L, the initial pH of fermentation medium was 7, and the inoculum size was 10%, the yield of vivianite could be increased. Under these conditions, the yield of vivianite was 153.0 ± 7.0 mg / L.

[0038] In this invention, the LB liquid culture medium is prepared in the following proportions: 10 g tryptone, 5 g yeast extract, and 10 g NaCl per 1 L of distilled water, with a pH of 7.

[0039] LB solid medium: Agar is added to LB liquid medium, with an agar content of 1.5% (by mass).

[0040] Fe(OH)3 solution is prepared according to the following ratio: Weigh 3 g FeCl3·6H2O and dissolve it in 100 mL of distilled water. Add 1 M NaOH solution dropwise under continuous stirring to adjust the pH value to 7.

[0041] In this embodiment, the starting strain, *Shewanella xiaensis* CQ-Y1, was isolated from produced water from an oilfield. Its complete genome sequence has been uploaded to the National Center for Biotechnology Information (NCBI) in the United States, with the accession number CP092630.1; its 16S rRNA sequence has been uploaded to the NCBI in the United States, with the accession number NR_116732.1. This strain is currently stored in the inventor's laboratory, and the public can obtain it solely for non-commercial purposes to replicate the embodiments described in this invention.

[0042] Unless otherwise specified, all techniques or conditions used in the embodiments are conventional methods or performed according to the techniques or conditions described in the literature in this field, or according to the product instructions. Reagents used, unless otherwise specified, are all conventional products that can be purchased from legitimate channels or prepared according to conventional methods in this field. Instruments used, unless otherwise specified, are all conventional products that can be purchased from legitimate channels. Solutions involved in this invention, unless otherwise specified, are prepared using water as the solvent.

[0043] The following is a description through specific embodiments.

[0044] Example 1

[0045] Using Shewanella xiaensis CQ-Y1 as the wild-type strain (starting strain) for... Ion mutagenesis screening includes the following steps:

[0046] (1) Shewanella xiaensis CQ-Y1 was inoculated into LB liquid medium and cultured at 30℃ for 24 h. The resulting culture medium was prepared with physiological saline to a cell concentration of 10. 8 Bacterial suspension of cells / mL.

[0047] (2) Take 2 mL of the bacterial culture from step (1) into an irradiation dish, and irradiate the bacterial culture of Shewanella xiaensis CQ-Y1 using the vertical irradiation biological terminal of the Lanzhou Heavy Ion Research Facility (HIRFL) at the National Laboratory for Heavy Ion Research. The irradiation dose is 10-200 Gy. The ion beam energy was 80 MeV / u, the dose rate was 40 Gy / min, the target-source distance was 130 cm, and three parallel beams were set up for each irradiation dose.

[0048] (3) Take 0.5 mL of the bacterial culture treated with different irradiation doses in step (2) and inoculate it into 50 mL of LB liquid medium. Culture at 30℃ and 120 rpm for 24 h to obtain the seed culture in the logarithmic phase.

[0049] (4) The seed culture from step (3) was transferred into the fermentation medium at an inoculation rate of 5% (volume ratio). Fe(OH)3 solution was then added to the fermentation medium, with a volume ratio of Fe(OH)3 solution to fermentation medium of 10%. Fermentation was carried out in a constant temperature incubator at 30℃ for 36 h to obtain the fermentation broth.

[0050] The above fermentation medium formula includes: per 1 L of distilled water, 3 g KH2PO4, 12.8 g Na2HPO4·7H2O, 1 g NH4Cl, 2 g sodium lactate, 2 g yeast extract powder, and a pH value of 5.

[0051] (5) The yield of lapis lazuli in the fermentation broth was determined by the following steps: 10 mL of fermentation broth was collected and centrifuged at 2000 rpm for 5 min to obtain a composite precipitate containing bacteria and lapis lazuli. The composite precipitate was resuspended in distilled water to disperse the bacteria in the supernatant. The precipitate was then centrifuged again under the same conditions (2000 rpm, 5 min), and the supernatant rich in bacteria was discarded. The precipitate was resuspended in distilled water and centrifuged at 2000 rpm for 5 min to collect the lapis lazuli precipitate. The washed lapis lazuli precipitate was freeze-dried at -105℃ for 48 h and weighed to calculate the yield of lapis lazuli per liter of fermentation broth.

[0052] Based on the test results, the vivianite yield of *Shewanella macranthae* CQ-Y1 in Xiamen was calculated to be 73.8 ± 1.0 mg / L. The vivianite yields of each mutant strain after mutagenesis are shown in Table 1. Specifically, CQ-T10 was the mutant strain obtained after treatment with an irradiation dose of 10 Gy; CQ-T20 was the mutant strain obtained after treatment with an irradiation dose of 20 Gy; CQ-T40 was the mutant strain obtained after treatment with an irradiation dose of 40 Gy; CQ-T80 was the mutant strain obtained after treatment with an irradiation dose of 80 Gy; CQ-T120 was the mutant strain obtained after treatment with an irradiation dose of 120 Gy; CQ-T160 was the mutant strain obtained after treatment with an irradiation dose of 160 Gy; and CQ-T200 was the mutant strain obtained after treatment with an irradiation dose of 200 Gy. It can be seen that, compared with other strains obtained from mutagenesis screening, strain CQ-T200 has the highest lapis lazuli yield, reaching 101.1±1.4 mg / L.

[0053] Table 1. Blue iron ore yield of each strain after mutagenesis

[0054]

[0055] Example 2

[0056] CQ-T200 was inoculated onto LB solid medium and incubated at 30℃ for 48 h. The colony morphology of CQ-T200 was then observed. Figure 1 As shown, CQ-T200 colonies exhibit good morphology on LB solid medium, appearing orange, round, with neat edges, a smooth and opaque surface, and a slightly convex center, with a diameter of approximately 2.8-3.2 mm. Transmission electron microscopy (TEM) observation reveals that the bacteria are typically rod-shaped, approximately 0.5 μm wide and 2.5 μm long, with wrinkles on the cell surface and numerous pili (further details needed for accurate translation). Figure 2 Physiological analysis showed that the optimal growth pH for CQ-T200 in LB liquid medium was 7, the optimal temperature range was 25-40℃, and the optimal salinity range was 1%-2% (mass percentage). Genome sequencing results showed that its genome size was approximately 4.65 Mb. The strain was identified as *Shewanella xiaensis*. Shewanella xiamenensis ).

[0057] The present invention provides Xiamen Shewanella ( Shewanella xiamenensis CQ-T200, deposited at: China Center for Type Culture Collection (CCTCC), deposited at: Wuhan University, Wuhan, China, accession number: CCTCC NO: M20252555, deposited on: November 17, 2025.

[0058] Example 3

[0059] This invention provides a method for producing vivianite using *Shewanella xiaensis* CQ-T200, comprising the following steps: 0.5 mL of CQ-T200 seed culture (prepared using the method in Example 1) is inoculated into 10 mL of fermentation medium. The fermentation medium consists of: per 1 L of distilled water, 3 g KH₂PO₄, 12.8 g Na₂HPO₄·7H₂O, 0.5-2 g NH₄Cl, 1-4 g sodium lactate, and 2 g yeast extract, with a pH of 5. Fe(OH)₃ solution is then added to the medium, with a volume percentage of 10% between the Fe(OH)₃ solution and the fermentation medium. The mixture is incubated at 30°C for 48 h to obtain the fermentation broth. The fermentation broth is centrifuged at 2000 rpm for 5 min to obtain a composite precipitate containing bacterial cells and vivianite. The composite precipitate is resuspended in distilled water to disperse the bacterial cells in the supernatant. Subsequently, the mixture is centrifuged again under the same conditions (2000 rpm, 5 min), and the supernatant rich in bacterial cells is discarded. The precipitate was resuspended in distilled water and centrifuged at 2000 rpm for 5 min to collect the lapis lazuli precipitate. The washed lapis lazuli precipitate was freeze-dried at -105℃ for 48 h to obtain lapis lazuli ( Figure 3 ).

[0060] Example 4

[0061] The effect of sodium lactate concentration on vivianite yield was investigated using the following experimental methods:

[0062] (1) Prepare fermentation medium. The fermentation medium formula includes: per 1 L of distilled water, 3 g KH2PO4, 12.8 g Na2HPO4·7H2O, 1 g NH4Cl, 1-4 g sodium lactate (the specific values ​​are 1 g, 2 g, 3 g, and 4 g respectively), 2 g yeast extract powder, and the pH value is 5.

[0063] (2) Following the method in Example 3, the seed culture of strain CQ-T200 was transferred into the fermentation medium at an inoculation rate of 5% (volume ratio), and Fe(OH)3 solution was added to the fermentation medium. The volume ratio of Fe(OH)3 solution to fermentation medium was 10%. Fermentation was carried out in a constant temperature incubator at 30℃ for 48 h to obtain the fermentation broth.

[0064] (3) The yield of blue iron ore in the fermentation broth was detected by referring to Example 1.

[0065] The experimental results are shown in Table 2. When the sodium lactate concentration was 3 g / L, the strain CQ-T200 had the highest lapis lazuli yield, which was 118.9 ± 6.0 mg / L.

[0066] Table 2. Effect of different sodium lactate concentrations on lapis lazuli yield

[0067]

[0068] Example 5

[0069] The effect of ammonium chloride concentration on vivianite yield was investigated using the following experimental methods:

[0070] (1) Prepare fermentation medium. The fermentation medium formula includes: per 1 L of distilled water, 3 g KH2PO4, 12.8 g Na2HPO4·7H2O, 0.5-2 g NH4Cl (the specific values ​​are 0.5 g, 1 g, 1.5 g, and 2 g respectively), 2 g sodium lactate, 2 g yeast extract powder, and the pH value is 5.

[0071] (2) Following the method in Example 3, the seed culture of strain CQ-T200 was transferred into the fermentation medium at an inoculation rate of 5% (volume percentage), and Fe(OH)3 solution was added to the fermentation medium. The volume ratio of Fe(OH)3 solution to fermentation medium was 10%. Fermentation was carried out in an incubator at 30°C for 48 h to obtain the fermentation broth.

[0072] (3) The yield of blue iron ore in the fermentation broth was detected by referring to Example 1.

[0073] The experimental results are shown in Table 3. When the ammonium chloride concentration was 1 g / L, the strain CQ-T200 had the highest lapis lazuli yield, which was 111.1 ± 4.1 mg / L.

[0074] Table 3. Effects of different ammonium chloride concentrations on lapis lazuli production

[0075] Ammonium chloride concentration (g / L) Blue iron ore yield (mg / L) 0.5 91.4±5.6 1 111.1±4.1 1.5 97.5±5.5 2 92.1±4.1

[0076] Example 6

[0077] The effect of pH on vivianite yield was determined using the following experimental methods:

[0078] (1) Prepare fermentation medium. The fermentation medium formula includes: per 1 L of distilled water, 3 g KH2PO4, 12.8 g Na2HPO4·7H2O, 1 g NH4Cl, 2 g sodium lactate, 2 g yeast extract powder, and pH value of 3-9 (specific values ​​are 3, 5, 7, and 9 respectively).

[0079] (2) Following the method in Example 3, the seed culture of strain CQ-T200 was transferred into the fermentation medium at an inoculation rate of 5% (volume percentage), and Fe(OH)3 solution was added to the fermentation medium. The volume ratio of Fe(OH)3 solution to fermentation medium was 10%. Fermentation was carried out in an incubator at 30°C for 48 h to obtain the fermentation broth.

[0080] (3) The yield of blue iron ore in the fermentation broth was detected by referring to Example 1.

[0081] The experimental results are shown in Table 4. When the initial pH of the fermentation medium was 7, the strain CQ-T200 produced the highest yield of lapis lazuli, which was 132.5 ± 1.2 mg / L.

[0082] Table 4. Effects of different pH values ​​on lapis lazuli yield

[0083]

[0084] Example 7

[0085] To determine the effect of inoculum size on vivianite production, the experimental method included the following steps:

[0086] (1) Prepare the fermentation medium. The fermentation medium formula includes: 3 g KH2PO4, 12.8 g Na2HPO4·7H2O, 1 g NH4Cl, 2 g sodium lactate, and 2 g yeast extract per 1 L of distilled water, with a pH value of 5.

[0087] (2) Following the method in Example 3, the seed culture of strain CQ-T200 was transferred into the fermentation medium at inoculation amounts of 1%, 5%, 10%, and 20% (all by volume percentage), respectively. Fe(OH)3 solution was then added to the fermentation medium, with a volume ratio of Fe(OH)3 solution to fermentation medium of 10%. Fermentation was carried out at 30°C for 48 h to obtain the fermentation broth.

[0088] (3) The yield of blue iron ore in the fermentation broth was detected by referring to Example 1.

[0089] The experimental results are shown in Table 5. When the inoculum amount was 10%, the vivianite yield of strain CQ-T200 was the highest, which was 136.0±2.5 mg / L.

[0090] Table 5. Effects of different inoculum amounts on lapis lazuli yield

[0091]

[0092] Example 8

[0093] This invention provides a method for producing vivianite using strain CQ-T200, comprising the following steps:

[0094] (1) Prepare the fermentation medium. The fermentation medium formula includes: per 1 L of distilled water, 3 g KH2PO4, 12.8 g Na2HPO4·7H2O, 1 g NH4Cl, 3 g sodium lactate, 2 g yeast extract powder, and the pH value is 7.

[0095] (2) Following the method in Example 3, the seed culture of strain CQ-T200 was transferred into the fermentation medium at an inoculation rate of 10% (volume ratio), and Fe(OH)3 solution was added to the fermentation medium. The volume ratio of Fe(OH)3 solution to fermentation medium was 10%. Fermentation was carried out in a constant temperature incubator at 30℃ for 48 h to obtain the fermentation broth.

[0096] (3) The yield of lapis lazuli in the fermentation broth was detected using the same method as in Example 1. The results showed that the yield of lapis lazuli using the above method reached 153.0 ± 7.0 mg / L.

[0097] 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. A strain of Shewanella xiaensis, characterized in that, The strain name is Shewanella xiaensis ( Shewanella xiamenensis CQ-T200, accession number CCTCC NO: M 20252555.

2. A microbial agent, characterized in that, Includes the *Shewanella xiaensis* of claim 1 and / or the fermentation product of the *Shewanella xiaensis* of claim 1.

3. A method for producing vivianite, characterized in that, Blue iron ore is produced using the *Shewanella maculata* of claim 1 or the bacterial agent of claim 2.

4. The method for producing vivianite according to claim 3, characterized in that, The *Shewanella xiaensis* of claim 1 or the bacterial agent of claim 2 is added to a fermentation medium with Fe... 3+ Using it as a substrate, fermentation culture is performed.

5. The method for producing vivianite according to claim 4, characterized in that, The vaccination rate is 1%-20%.

6. The method for producing vivianite according to claim 4 or 5, characterized in that, The initial pH of the fermentation medium is 3-9.

7. The method for producing vivianite according to claim 4 or 5, characterized in that, The fermentation medium contains sodium lactate, with a concentration of 1-4 g / L.

8. The method for producing vivianite according to claim 4 or 5, characterized in that, The fermentation medium contains ammonium chloride at a concentration of 0.5-2 g / L.

9. The method for producing vivianite according to claim 4 or 5, characterized in that, The fermentation culture temperature was 30℃, and the fermentation time was 48 h. The culture contained Fe. 3+ The volume ratio of the solution to the fermentation medium is 10%, and the fermentation medium also contains hydrogen phosphate ions.

10. The application of the *Shewanella maculata* of claim 1 or the bacterial agent of claim 2 in the production of vivianite.

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