Bacillus velezensis inducing bacterium and application thereof in lipopeptide production

Abstract

The invention relates to the technical field of microorganisms, and discloses bacillus velezensis inducing bacteria and application thereof in lipopeptide production, the bacillus velezensis is preserved in China General Microbiological Culture Collection Center (CGMCC) on April 6, 2022, and the preservation number is CGMCC No.24640. The invention further discloses a preparation method of the bacillus velezensis inducing bacteria. According to the invention, the bacillus velezensis is taken as an original strain, and a mutant strain with high yield of lipopeptide is successfully screened out through the technical means of ultraviolet mutagenesis, preliminary screening, secondary screening and the like, so that the yield of lipopeptide is remarkably increased. Besides, the chelating capacity of the produced lipopeptide and metal ions is evaluated, the result shows that the binding content of zinc ions in the chelate reaches 478.2012 mg / 100g, and further bacteriostatic experiments show that the chelate can effectively inhibit growth of micrococcus luteus.

Description

Technical Field

[0001] The present invention relates to the technical field of microorganisms, in particular to an induced bacterium of Bacillus velezensis and application thereof in producing lipopeptides. Background Art

[0002] Studies have shown that complexes formed by peptides and metal ions exhibit significant biological activities such as antibacterial and antiseptic properties. Lipopeptides, in particular, have become a new research focus due to their diverse biological activities, excellent stability, non-toxicity, and lack of drug resistance induction. Importantly, lipopeptides have a significant inhibitory effect on pathogens in animals, such as Micrococcus luteus. When lipopeptides bind to metal ions, they form a more stable molecular structure, thereby enhancing their antibacterial activity and ensuring their effective action at the site of lesions, fully demonstrating their therapeutic potential.

[0003] Micrococcus luteus is widely present in the air, soil, and human skin. When the human immune system is weakened or traumatized, the bacteria can invade the bloodstream through the gastrointestinal tract, leading to clinical symptoms such as localized infection and wound suppuration. Therefore, developing antimicrobial agents that effectively inhibit its growth while being safe and harmless to the human body is a key research priority. Summary of the Invention

[0004] In view of this, the present invention proposes an induced bacterium of Bacillus velezensis and its application in producing lipopeptides, aiming to provide an induced bacterium that can efficiently synthesize lipopeptides with significant antibacterial activity, as well as the application of the induced bacterium in the preparation of antibacterial agents.

[0005] The present invention proposes a Bacillus velezensis, which was deposited on April 6, 2022, at the General Microbiology Center of China Culture Collection Administration, located at No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, with a deposit number of CGMCC No. 24640 and a classification name of Bacillus velezensis.

[0006] The present invention also provides an application of the Bacillus Velezii in producing lipopeptides.

[0007] The present invention also provides a lipopeptide-producing strain, which is obtained by subjecting the above-mentioned Bacillus Velezii to ultraviolet mutagenesis.

[0008] The present invention also provides a lipopeptide, which is produced by the above-mentioned Bacillus Velezii or the above-mentioned lipopeptide-producing strain.

[0009] The present invention also provides a lipopeptide-metal ion chelate, which is obtained by chelating the metal with the above-mentioned lipopeptide.

[0010] Preferably, the metal is calcium, magnesium or zinc.

[0011] The application also provides the use of the above-mentioned lipopeptide-metal ion chelate in bacteriostasis.

[0012] The application also provides the use of the above-mentioned lipopeptide-metal ion chelate in the preparation of a bacteriostatic product.

[0013] The application also provides a bacteriostatic product, wherein the active ingredient of the bacteriostatic product comprises the above-mentioned lipopeptide-metal ion chelate.

[0014] Compared with the prior art, the application has the following beneficial effects:

[0015] The application uses Bacillus velezensis (CGMCC No.24640) as an original strain, and successfully screens a mutant strain with high lipopeptide yield through the technical means of ultraviolet mutagenesis, preliminary screening and rescreening. The lipopeptide yield of the mutant strain is significantly improved from 0.220 mg / mL to 0.708 mg / mL. In addition, the chelating ability of the produced lipopeptide and metal ions (zinc ions) is also studied, and it is found that the content of the chelate reaches 478.2012 mg / 100 g. Further bacteriostatic experiments show that the chelate can effectively inhibit the growth of Micrococcus luteus, and the minimum bacteriostatic concentration is 0.125 mg / mL. BRIEF DESCRIPTION OF DRAWINGS

[0016] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The detailed description is made with reference to the accompanying drawings.

[0017] Figure 1 For the synthesis pathway of lipopeptide;

[0018] Figure 2 For the influence of ultraviolet induction time on the lethality of the strain;

[0019] Figure 3 For the results of the preliminary screening of the strain, wherein a is a hemolytic ring, and b is a K value;

[0020] Figure 4 For the results of the rescreening of the strain, wherein a is the lipopeptide yield of the strain, and b is the passage stability;

[0021] Figure 5 For the influence of different medium components on the lipopeptide yield of the strain, wherein a is a carbon source, b is an inorganic salt, c is an organic nitrogen source, and d is an inorganic nitrogen source;

[0022] Figure 6 The effect of different culture conditions on the lipopeptide production of the strain, where a is pH, b is seed age, c is inoculum size, and d is temperature;

[0023] Figure 7 The experimental results of antibacterial effect, among which (A) is the antibacterial effect of Oxford cup method on Micrococcus luteus, and (B) is the effect of different ratios of metal (Ca, Mg, Zn)-CL on the growth of Micrococcus luteus;

[0024] Figure 8 The effects of CL and metal (Ca, Mg, Zn)-CL / 1:2 treatment on the morphology of Micrococcus luteus;

[0025] Figure 9 Element distribution on the surface of lipopeptide and metal ion chelate (1:2);

[0026] Figure 10 Electron micrograph of lipopeptide and metal ion chelate (1:2);

[0027] Figure 11 AFM image of lipopeptide and metal ion chelate (1:2). DETAILED DESCRIPTION

[0028] Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art. It should be noted that, unless there is a conflict, the embodiments of the present disclosure and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0029] Example 1

[0030] 1. Condition Exploration

[0031] 1. Selection of starting strain

[0032] The starting strain, Bacillus velezensis, was isolated from healthy human feces and, after identification, was deposited with the General Microbiology Center of the China General Culture Collection (CGMCC) on April 6, 2022, under the accession number CGMCC No. 24640. Genome sequencing revealed that genes such as SrfAA, SrfAB, SrfAC, and SrfAD may be involved in the expression of lipopeptides. Lipopeptide assays were performed on the fermentation supernatants of these strains, demonstrating their presence (at a concentration of 0.220 mg / mL). Figure 1A pathway diagram for the synthesis of lipopeptides via non-ribosomal pathways from the KEGG database is shown.

[0033] 2. UV induction and initial and rescreening results

[0034] (1) UV induction

[0035] The starting strain was subjected to UV mutagenesis treatment. When the mutagenesis distance was set at 30 cm, the lethality curve of Bacillus velezensis was as follows: Figure 2 As shown. Low-dose mutagenesis results in fewer negative mutations, morphological mutations, and reversion mutations, which helps maintain the genetic stability of the mutagenized strain. Therefore, we selected an irradiation dose with a lethality of approximately 80% and determined the optimal UV irradiation time to be 90 seconds.

[0036] (2) Initial screening results

[0037] The blood plate method was used to screen the high-yielding strains of lipopeptides. The high-yielding colonies would form an obvious hemolysis zone on the blood plate, and the K value of the hemolysis zone was positively correlated with the lipopeptide production. Figure 3 As shown in the figure, we selected 13 mutagenic strains with larger K values ​​for rescreening.

[0038] (3) Rescreening results

[0039] The 13 mutant strains (numbered 1-13) obtained from the initial screening were rescreened, and the starting strain was numbered 0. The test results are as follows Figure 4 As shown in the figure, strains numbered 1, 11, and 13 produced higher lipopeptide yields. After six subcultures, the average yields of these three strains were 0.207 mg / mL, 0.386 mg / mL, and 0.340 mg / mL, respectively. Therefore, we selected strain 11 for further study.

[0040] 3. Culture medium optimization

[0041] Different culture medium components have significant effects on the production of lipopeptides by the induced strains, such as Figure 5 As shown in the figure. In carbon source optimization, the lipopeptide production of the induced strain in the fermentation broth supplemented with yeast extract was the highest (0.405 mg / mL). In inorganic salt optimization, when the Na+ concentration in the fermentation medium was 0.1 M, the induced strain produced the highest lipopeptide concentration, reaching 0.416 mg / mL. When sodium glutamate was used as the organic nitrogen source, the lipopeptide production could be increased to 0.545 mg / mL. Among inorganic nitrogen sources, ammonium sulfate and sodium nitrate both significantly increased the lipopeptide production of the induced strain. However, from the perspective of economy and safety, ammonium sulfate was more suitable as the inorganic nitrogen source, with a lipopeptide production of 0.690 mg / mL.

[0042] 4. Optimization of culture conditions

[0043] Different culture conditions have a significant effect on the lipopeptide production of the mutagenic strain, such as Figure 6 As shown in the figure, the initial pH value was 7.0, and the lipopeptide yield was the best, reaching 0.695 mg / mL. The lipopeptide yield was the highest at 8 hours of inoculation, reaching 0.708 mg / mL. The lipopeptide yield was the highest at 2% inoculation, reaching 0.690 mg / mL. In terms of culture temperature, the yield was the highest at 35°C, reaching 0.692 mg / mL.

[0044] 2. Preparation of efficient synthetic natural lipopeptides using optimal parameters

[0045] 1. Activation of starting strain

[0046] The Bacillus velezensis strain has been deposited with the General Microbiology Center of the China General Microbiology Culture Collection (CGMCC) under the accession number CGMCC No. 24640. The strain was inoculated into LB medium, and the fermentation parameters were set at 37°C and 200 rpm for 24 hours.

[0047] 2. UV mutagenesis treatment

[0048] Turn on the UV lamp to preheat for 20 minutes, dilute the activated strain to 10 8 To determine the CFU / mL concentration, 9 mL was poured into a 9 cm diameter plate. The plate was then placed on a sterile magnetic stirrer (25 rpm) and irradiated with UV light for 90 seconds. The irradiated bacterial solution was diluted and spread on a plate under red light (covered with black cloth after spreading to prevent UV damage from being repaired by visible light), followed by incubation at 37°C for 48 hours.

[0049] 3. Preliminary screening

[0050] Transfer the induced colonies to blood plates and incubate at 37°C for 24 hours. Select the three strains with the largest hemolysis zone (K value) for rescreening. Blood plates are prepared by adding sterile defibrinated sheep blood to LB medium to a final concentration of 50 mL / L.

[0051] 4. Rescreening

[0052] The lipopeptide content of the strains obtained in the initial screening was measured, and the culture was repeated six times to screen out strains with excellent performance and genetic stability.

[0053] 5. Cultivation of target strains

[0054] The selected target strain was inoculated into a specific culture medium and cultured for 48 hours at an initial pH of 7.0, a culture temperature of 35°C, and a 2% inoculum to obtain a fermentation broth. The culture medium consisted of 10 g / L yeast extract, 5 g / L sodium L-glutamate, 5 g / L sodium chloride, and 5 g / L ammonium sulfate.

[0055] 6. Extraction of lipopeptides

[0056] The fermentation broth was centrifuged at 10,000 r / min for 15 minutes at 4°C, the precipitate was removed, and the supernatant was collected. The pH value of the supernatant was adjusted to 2.0 using 6 mol / L HCl and allowed to stand overnight at 4°C. The next day, the broth was centrifuged at 10,000 r / min for 15 minutes, the supernatant was removed, and methanol at 1 / 10 the volume of the original fermentation broth was added to the precipitate. The mixture was shaken for 2 hours, centrifuged, and the supernatant was collected. This was repeated twice. The supernatants collected twice were combined and evaporated to obtain a yellow-brown crude extract. The lipopeptide extract was obtained by acid washing twice with a H2SO4 solution at a pH of 2.0 and freeze-dried.

[0057] Example 2 Preparation of lipopeptide-metal ion chelate using the lipopeptide extract prepared in Example 1

[0058] 1. Preparation method

[0059] Since calcium, magnesium and zinc ions are common multivalent metal ions, calcium chloride, magnesium chloride and zinc sulfate are selected as complex ligands in this embodiment, which are represented by CL-Ca, CL-Mg and CL-Zn respectively, while lipopeptide is represented by CL.

[0060] The pH value of the 1 mg / mL lipopeptide aqueous solution was adjusted to 7 by sodium hydroxide, and then calcium chloride, magnesium chloride, and zinc sulfate solutions with a concentration of 0.1 mol / L were mixed with the lipopeptide aqueous solution at a ratio of 2:1, 1:1, and 1:2 (g:mmol), respectively. The mixture was shaken at 25±5°C for 30 minutes, and the lipopeptide-metal ion complex was prepared by dialysis (dialysis bag molecular weight 1000Da) for 48 hours using freeze-drying technology.

[0061] In this example, lipopeptide is represented by CL; the complexes of calcium ions are represented by CL-Ca / 2:1, CL-Ca / 1:1, and CL-Ca / 1:2, respectively; the complexes of magnesium ions are represented by CL-Mg / 2:1, CL-Mg / 1:1, and CL-Mg / 1:2, respectively; and the complexes of zinc ions are represented by CL-Zn / 2:1, CL-Zn / 1:1, and CL-Zn / 1:2, respectively.

[0062] 2. Antibacterial ability test

[0063] 1. Experimental methods

[0064] Dilute the pathogenic bacteria in the logarithmic growth phase to 10 7 CFU / mL concentration. Under a sterile operating table, evenly spread 100 μL of bacterial solution onto LB agar plates. Next, place 8 mm diameter Oxford cups equidistantly on the coated plates and add 200 μL of the sample to each. A sample-free solvent was used as a control. After incubating the plates at 4°C for 1 hour, transfer them to a 37°C incubator and incubate for 24 hours. The diameter of the inhibition zone was then measured. Each experiment was repeated three times.

[0065] An indicator bacterial suspension in the logarithmic growth phase was inoculated at a 2% (v / v) inoculum into LB medium containing surfactin samples at final concentrations of 0.25 mg / mL and 0.5 mg / mL, respectively. LB medium without sample served as a blank control. The inoculated culture medium was placed in an automated microbial growth curve analyzer at a temperature of 37°C. The absorbance at 600 nm was measured every hour. Three replicates were set for each experiment.

[0066] 2. Experimental results

[0067] Due to its ability to penetrate and disrupt microbial cell membranes, CL exhibits significant antimicrobial activity. After 24 hours of incubation, the diameter inhibition zone (DIZ) against Micrococcus luteus was 16.79 mm, while the DIZ values ​​for the CL-Ca, CL-Mg, and CL-Zn complexes were 16.95 mm, 15.43 mm, and 19.29 mm, respectively (the ratio of metal ions to CL in each complex was 1:2). These results suggest that metal ion coordination can influence the antimicrobial activity of CL, and this activity is metal ion-dependent. While binding to calcium ions had no significant effect on the antimicrobial activity of CL, binding to magnesium ions reduced the antimicrobial activity of the lipopeptide, while binding to zinc ions significantly enhanced it.

[0068] Analysis of the growth curve of Micrococcus luteus revealed that the lipopeptide exerts its antibacterial effect primarily by prolonging the lag phase, which can be extended to 7-8 hours. Furthermore, in the late fermentation phase, the OD600nm value of 0.5 mg / mL CL was higher than that of the control group, likely due to the development of drug resistance in the bacteria. As can be seen from the figure, the addition of CL-Ca and CL-Mg complexes at different concentrations (0.25 mg / mL and 0.5 mg / mL) did not show significant differences compared to CL. However, the CL-Zn complex exhibited significant antibacterial activity, and the higher the zinc ion addition ratio, the stronger the antibacterial effect, showing a dose-dependent effect. In particular, at a concentration of 0.5 mg / mL, the CL-Zn complex (added at a ratio of 1:2) completely inhibited the growth of Micrococcus luteus within 24 hours.

[0069] 3. Minimum inhibitory concentration test

[0070] 1. Experimental process

[0071] In this study, a two-fold dilution method was used to dilute chloride complexes formed by lithium chloride (Cl) and metal ions (calcium, magnesium, and zinc) to concentrations of 1 mg / mL, 0.5 mg / mL, 0.25 mg / mL, 0.125 mg / mL, and 0.063 mg / mL. The solutions were measured according to established methods, and the diameters of the inhibition zones were compared and analyzed. The minimum concentration at which an inhibition zone appeared was defined as the minimum inhibitory concentration (MIC).

[0072] 2. Results

[0073] The minimum inhibitory concentration (MIC) is the lowest concentration of a drug that effectively inhibits microbial growth. In this experiment, the MIC was assessed by measuring the diameter inhibition zone (DIZ). Using the two-fold dilution method, the MIC values ​​of lithium chloride (CL) and its complexes with calcium (Ca) and magnesium (Mg) against Micrococcus luteus were 0.25 mg / mL, while the MIC value of the zinc chloride (CL-Zn) complex was 0.125 mg / mL. Table 1 shows the MIC results of CL and different ratios of metal (Ca, Mg, Zn)-CL against Micrococcus luteus.

[0074] Table 1

[0075] Concentration (mg / mL) 1 0.5 0.25 0.125 CL 12.91±0.67c 10.83±1.04d 8.56±0.72c - CL-Ca / 2:1 13.82±0.82c 11.50±0.74d 8.79±0.96c - CL-Ca / 1:1 13.81±0.28c 10.89±0.80d 9.47±1.27c - CL-Ca / 1:2 13.61±0.85c 10.68±0.61d 8.55±0.51c - CL-Mg / 2:1 12.52±0.77c 11.12±0.95d 8.20±0.24c - CL-Mg / 1:1 13.44±0.50c 10.78±0.75d 8.66±0.51c - CL-Mg / 1:2 13.33±0.78c 11.44±0.37d 8.30±0.28c - CL-Zn / 2:1 16.43±0.90b 13.52±1.42c 11.40±0.33b 8.32±0.26c CL-Zn / 1:1 17.99±0.60a 15.41±0.56b 11.91±0.72b 9.05±0.51b CL-Zn / 1:2 18.84±0.63a 16.89±0.44a 13.39±0.59a 9.61±0.53a

[0076] Note: The table shows the diameter inhibition zone (DIZ) of Micrococcus luteus, unit: cm.

[0077] 4. Bacterial morphology

[0078] 1. Experimental process

[0079] The indicator bacteria solution in the logarithmic growth phase was centrifuged at 4000r / min for 10 minutes, and the bacterial pellet was taken and diluted with PBS to a bacterial suspension concentration of 107CFU / mL. CL, CL-Ca, and CL-Zn were added thereto at a ratio of 1:2, so that the final concentrations reached 0.25mg / mL and 0.5mg / mL, respectively. The culture was shaken at 37°C and 200r / min for 24 hours, and then the bacterial pellet was washed twice with sterile PBS. It was fixed overnight with 2.5% glutaraldehyde and dehydrated with 30%, 50%, 70%, 90%, and 100% ethanol for 20 minutes each, followed by freeze-drying. After ion sputtering gold treatment, it was observed and imaged using a scanning electron microscope at a voltage of 7kV.

[0080] 2. Results

[0081] According to the results of the antibacterial ability test and the minimum inhibitory concentration test, CL-Zn showed a significant antibacterial effect, among which the addition ratio of 1:2 had the best effect. Therefore, the 1:2 addition ratio of the three chelates was selected, and the effective concentration was 0.25 mg / mL. The bacterial morphology was observed, and the results were as follows: Figure 8 shown.

[0082] After 24 hours of treatment with 0.25 mg / mL CL-Zn, the bacteria showed a large amount of cell debris and holes on the cell membrane surface. The bacteria treated with CL-Ca and CL-Mg showed slight fission morphology, while there was no significant difference in morphology between the CL-treated group and the control group CK under electron microscopy.

[0083] Example 3

[0084] 1. Preparation of Lipopeptide-Metal Ion Chelates

[0085] According to the experimental results of Example 2, CL-Zn exhibited significant antibacterial activity, and the antibacterial effect was particularly optimal at a 1:2 ratio. Based on this, the three chelates used in this study all adopted a 1:2 ratio.

[0086] First, the pH value of the lipopeptide aqueous solution (concentration of 1 mg / mL) was adjusted to 7 by sodium hydroxide. Subsequently, calcium chloride, magnesium chloride and zinc sulfate solutions with a concentration of 0.1 mol / L were mixed with the lipopeptide aqueous solution at a weight ratio of 1:2 (g:mmol). The mixed solution was uniformly shaken for 30 minutes at 25±5°C, and then dialyzed (using a dialysis bag with a molecular weight of 1000Da) for 48 hours. After dialysis, the solution was freeze-dried to obtain the corresponding complex.

[0087] In this example, the lipopeptide is labeled as CL; the calcium chelate is labeled as CL-Ca; the magnesium chelate is labeled as CL-Mg; and the zinc chelate is labeled as CL-Zn.

[0088] 2. Experiment

[0089] 1. Metal ion binding capacity

[0090] Calcium and magnesium ions have weaker binding abilities for lithium chloride (Cl) than zinc ions. Zinc ions, on the other hand, exhibit stronger binding abilities for lithium chloride. Table 2 shows the results of metal ion binding assays for lithium chloride and its complexes with metal ions (calcium, magnesium, and zinc).

[0091] Table 2

[0092] CL-Ca CL-Mg CL-Zn Metal binding content (mg / 100g) 18.03017 91.4535 478.2012

[0093] 2. Basic physical and chemical properties of chelates

[0094] Lipopeptides with cyclic peptide segments typically carry a negative charge due to the presence of aspartic acid and glutamic acid. The introduction of metal ions leads to a decrease in the absolute value of the potential, particularly with the addition of magnesium ions. The positive charge neutralization effect of calcium, magnesium, and zinc ions enhances the micelle stability of the surfactant, thereby promoting the micellization process. The addition of divalent counterions reduces the electrostatic repulsion between lipopeptides, promoting the formation of regular micelle aggregates with small particle size.

[0095] The binding of metal ions to the lipopeptide significantly increases the hydrophobicity of the chelate. Specifically, the surface hydrophobicity of CL-Zn reaches a high of 499.83, while that of calcium and magnesium ions increases to 377.17 and 318.65, respectively. This suggests that the addition of metal ions promotes the exposure of more hydrophobic groups. Table 2 shows the potential and hydrophobicity data for CL and metal (Ca, Mg, Zn)-CL.

[0096] Table 3

[0097] CL CL-Ca CL-Mg CL-Zn Zeta-potential / mV 49.61±1.19c 34.59±3.66b 24.27±0.56a 32.27±0.11b hydrophobicity 161.16±0.43d 377.17±0.89b 318.65±1.89c 499.83±1.31a

[0098] 3. Element distribution and mass ratio

[0099] Energy dispersive spectrometers can measure the distribution of elements on the sample surface and their mass fractions. The study found that the addition of metal ions increased the proportion of oxygen, particularly in CL-Ca and CL-Zn, which increased to 18.2% and 19.1%, respectively, compared to 15.7% in CL. The addition of metal ions loosened the structure of the lipopeptide chelate, and the interaction with the metal ions altered the previously dense structure of the lipopeptide surface (the nitrogen element and long fatty chains were internal to the molecular structure and were not detected).

[0100] 4: Morphological observation of chelates

[0101] (1) Scanning electron microscopy (SEM)

[0102] The figure below shows the microstructure of lipopeptide and its metal chelate. Under SEM, CL appears as disordered flakes and rods with a dense and smooth surface. 2+ After bonding, the surface roughness did not change significantly. The Cl-Zn structure became loose, both in sheet and rod structure. 2+ After binding, the sheet and rod structures remain smooth, but some smaller irregular structures become loose. This shows that different metal ions have different effects on CL.

[0103] (2) Atomic force microscopy (AFM)

[0104] AFM was used to observe the morphology of the sample at low concentration (20 μg / mL) to determine its aggregation state. Figure 11 As shown in Figure A, CL is approximately 28 nm tall, forming an ellipsoid with a diameter of approximately 220 nm. The addition of calcium and zinc ions further elongates the lipopeptide, resulting in a sheet-like structure approximately 2.6 nm tall. CL-Ca also exhibits smaller spherical structures with a diameter of approximately 100 nm. Figure 11 The diameter of the CL-Zn sheet structure in C is about 400 nm. This may be due to the lower critical micelle concentration and stronger hydrophobicity of the metal chelate, which causes it to exhibit different aggregation states at the same concentration, changing from spherical to lamellar, and the structure is more stretched.

[0105] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A Bacillus Velezii, characterized in that The Bacillus Velezii was deposited at the General Microbiology Center of the China Culture Collection Administration on April 6, 2022, with the deposit number CGMCC No. 24640.

2. Use of the Bacillus Velezii according to claim 1 in producing lipopeptides.

3. A lipopeptide-producing strain, characterized in that: The lipopeptide-producing strain is obtained by subjecting the Bacillus Velez subtilis described in claim 1 to ultraviolet mutagenesis.

4. A lipopeptide, characterized in that The lipopeptide is produced by the Bacillus Velezii described in claim 1 or the lipopeptide-producing strain described in claim 3.

5. A lipopeptide-metal ion chelate, characterized in that: The lipopeptide-metal ion chelate is obtained by chelating a metal with the lipopeptide according to claim 4.

6. The lipopeptide-metal ion chelate according to claim 5, characterized in that The metal is calcium, magnesium or zinc.

7. Use of the lipopeptide-metal ion chelate according to claim 5 in antibacterial treatment.

8. Use of the lipopeptide-metal ion chelate according to claim 5 in the preparation of an antibacterial product.

9. An antibacterial product, characterized in that: The active ingredient of the antibacterial product includes the lipopeptide-metal ion chelate according to claim 5.

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