Stenotrophomonas and application thereof

Abstract

The invention discloses stenotrophomonas and application thereof, and belongs to the technical field of microorganisms. The stenotrophomonas maltophilia provided by the invention is stenotrophomonas maltophilia, the strain number of the stenotrophomonas maltophilia is M22, and the registration number of the stenotrophomonas maltophilia in the China General Microbiological Culture Collection Center is CGMCC (China General Microbiological Culture Collection Center) No. 32084. The stenotrophomonas screened by the invention can degrade AHLs in a membrane bioreactor system, effectively alleviates the biological pollution of a membrane, and has great significance for the development of the field of sewage treatment.

Description

Technical Field

[0001] The invention belongs to the technical field of microorganisms, and in particular relates to oligotrophic mononas and application thereof. Background Art

[0002] With the increasing demand for water resource reuse, membrane bioreactor (MBR) has become one of the most efficient processes in wastewater treatment technology due to its advantages such as good effluent quality, low sludge production, small footprint, and flexible operation and control. However, the inevitable membrane biofouling problem in the operation of MBR has greatly increased the additional energy consumption and cost of the technology in the operation and maintenance process, becoming the main bottleneck restricting the stable and efficient operation and further large-scale application of MBR. Traditional membrane fouling control research mainly focuses on membrane cleaning (physical cleaning, chemical cleaning, biological / biochemical cleaning), adding additives (biomass, activated carbon, flocculants, etc.), optimizing operating conditions (adjusting SRT and HRT, controlling aeration and sludge concentration, etc.), and modifying membranes. However, since membrane biofouling is a spontaneous behavior of microbial communities, these methods cannot fundamentally inhibit the formation of biofilms, and the control effect on membrane fouling is limited.

[0003] Quorum sensing (QS) refers to the mechanism by which bacteria can sense the density of their colonies by secreting signal molecules and detecting their concentrations, and then regulate gene expression to control collective behavior. Microorganisms use signal molecules of different structures for intra- and inter-species communication. It has been confirmed that there are three different types of signal molecules: AHLs for communication between Gram-negative bacteria, autoinducing peptides (AIPs) for communication between Gram-positive bacteria, and diesters (AI-2) for inter-species communication. Since Gram-negative colonies are the most abundant in MBRs and dominate the microbial community, it is generally believed that inter-species communication between bacteria in MBRs is mainly based on the signal molecule AHL.

[0004] Quorum quenching (QQ) refers to a mechanism that effectively interferes with quorum sensing communication by inhibiting the expression of quorum sensing-related genes. Quorum quenching effectively reduces membrane biocontaminants in MBR and increases membrane permeation flux by interfering with quorum sensing between microorganisms without affecting the microbial biomass and pollutant removal effect in MBR.

[0005] The strains that can degrade N-acyl-L-homoserine lactones (AHLs) signal molecules to a concentration below a certain threshold and inhibit the expression of QS-related genes are strains with quorum sensing quenching ability (QQ bacteria). Using AHL as the only carbon source, researchers have isolated and screened Microbacteriumtestaceum StLB037, Rhodococcus sp. B5, Rhodococcus sp. BH4, Pseudomonas sp. 1A1, Rhodococcus erythropolis W2 and other QQ bacteria strains. However, the QQ bacteria resources reported so far are still very limited.

[0006] Therefore, it is necessary to screen more quorum sensing quenching bacteria to promote the application of quorum sensing quenching in the field of water treatment. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a new quorum sensing quenching sterilization. The technical problem to be solved is not limited to the described technical subject matter, and those skilled in the art can clearly understand other technical subjects not mentioned in this article through the following description.

[0008] In order to solve the above technical problems, the present invention provides the following technical solutions: The present invention provides a quorum sensing quenching sterilization, wherein the quorum sensing quenching sterilization is Stenotrophomonas maltophilia ( Stenotrophomonas maltophilia ), its strain number is M22, and its registration number at the General Microbiology Center of China Culture Collection Administration is: CGMCC No.32084.

[0009] The present invention provides a culture of the aforementioned Stenotrophomonas maltophilia, which is a substance obtained by culturing the aforementioned Stenotrophomonas maltophilia in a microbial culture medium.

[0010] The culture contains Stenotrophomonas maltophilia ( Stenotrophomonas maltophilia )M22.

[0011] In the above culture, the culture is a culture of Stenotrophomonas maltophilia ( Stenotrophomonas maltophilia ) The fermentation product obtained by culturing M22 in microbial culture medium.

[0012] In the above culture, the substance includes the Stenotrophomonas maltophilia ( Stenotrophomonas maltophilia ) M22 and Stenotrophomonas maltophilia ( Stenotrophomonas maltophilia ) metabolites of M22.

[0013] The term "culture" refers to a general term for liquid or solid products (all substances in the culture container, i.e., fermentation products) that have a microbial community after artificial inoculation and culture. That is, the product obtained by growing and / or amplifying microorganisms, which can be a biologically pure culture of microorganisms, or it can contain a certain amount of culture medium, metabolites, and / or other components produced during the culture process. The term "culture" also includes a subculture obtained by subculturing a microorganism, which can be a culture of a certain generation or a mixture of several generations.

[0014] In the above culture, the microbial culture medium may be a solid culture medium or a liquid culture medium.

[0015] The present invention provides a bacterial agent, which contains the aforementioned Stenotrophomonas maltophilia or / and a metabolite of the aforementioned Stenotrophomonas maltophilia or / and the aforementioned culture.

[0016] Herein, the metabolites can be obtained from Stenotrophomonas maltophilia ( Stenotrophomonas maltophilia ) obtained from the fermentation broth of M22. Stenotrophomonas maltophilia ) The metabolites of M22 can be Stenotrophomonas maltophilia ) axenic metabolites of M22 or Stenotrophomonas maltophilia ( Stenotrophomonas maltophilia ) Bacterial metabolites of M22. Stenotrophomonas maltophilia ) The sterile metabolite (sterile fermentation filtrate) of M22 can be prepared as follows: culturing Stenotrophomonas maltophilia ( Stenotrophomonas maltophilia ) M22, filter to remove Stenotrophomonas maltophilia from liquid culture (fermentation broth) ( Stenotrophomonas maltophilia ) M22 is to obtain Stenotrophomonas maltophilia ( Stenotrophomonas maltophilia ) Axenic metabolites of M22. Stenotrophomonas maltophilia ) The bacterial metabolites of M22 can be prepared according to the following method: culturing Stenotrophomonas maltophilia ( Stenotrophomonas maltophilia ) M22, collect the fermentation broth (containing Stenotrophomonas maltophilia ( Stenotrophomonas maltophilia ) M22 and the substances secreted into the liquid culture medium), the fermentation broth is Stenotrophomonas maltophilia ( Stenotrophomonas maltophilia ) Bacterial metabolites of M22.

[0017] The active ingredient of the above-mentioned bacterial agent can be Stenotrophomonas maltophilia ( Stenotrophomonas maltophilia ) M22 and / or Stenotrophomonas maltophilia ( Stenotrophomonas maltophilia ) metabolites of M22 or / and the above-mentioned culture, the active ingredients of the above-mentioned bacterial agent may also contain other biological components or non-biological components, and those skilled in the art may determine the other active ingredients of the above-mentioned bacterial agent according to the effects of the bacterial agent.

[0018] In the above-mentioned bacterial agent, the bacterial agent may further include a carrier. The carrier may be a solid carrier or a liquid carrier.

[0019] The solid carrier may be a mineral material or a biological material; the mineral material may be at least one of peat, clay, talc, kaolin, montmorillonite, white carbon, zeolite, silica and diatomaceous earth; the biological material may be at least one of various crop straws, pine husks, straw, peanut shells, corn flour, bean flour, starch, peat and animal feces; the liquid carrier may be water; in the bacterial agent, the maltophilia oligotrophic monosaccharides ( Stenotrophomonas maltophilia ) M22 and / or Stenotrophomonas maltophilia ( Stenotrophomonas maltophilia ) The metabolites of M22 can exist in the form of cultured living cells, fermentation broth of living cells, filtrate of cell culture, or a mixture of cells and filtrate. The formulation of the bacterial agent can be in various forms, such as liquid, emulsion, suspension, powder, granule, wettable powder or water dispersible granule.

[0020] As required, a surfactant (such as Tween 20, Tween 80, etc.), a binder, a stabilizer (such as an antioxidant), a pH adjuster, etc. may also be added to the bacterial agent.

[0021] The present invention also provides any of the following uses of the aforementioned Stenotrophomonas maltophilia: A1) Quorum sensing of inhibitory strains; A2) preparing products that inhibit quorum sensing of strains; A3) Degradation of N-acyl homoserine lactone in membrane bioreactor system; A4) Preparing a product for degrading N-acyl homoserine lactone in a membrane bioreactor system.

[0022] The present invention also provides any of the following uses of the metabolites of the aforementioned Stenotrophomonas maltophilia: A1) Quorum sensing of inhibitory strains; A2) preparing products that inhibit quorum sensing of strains; A3) Degradation of N-acyl homoserine lactone in membrane bioreactor system; A4) Preparing a product for degrading N-acyl homoserine lactone in a membrane bioreactor system.

[0023] The present invention also provides any of the following uses of the aforementioned culture: A1) Quorum sensing of inhibitory strains; A2) preparing products that inhibit quorum sensing of strains; A3) Degradation of N-acyl homoserine lactone in membrane bioreactor system; A4) Preparing a product for degrading N-acyl homoserine lactone in a membrane bioreactor system.

[0024] The present invention also provides any of the following uses of the aforementioned bacterial agent: A1) Quorum sensing of inhibitory strains; A2) preparing products that inhibit quorum sensing of strains; A3) Degradation of N-acyl homoserine lactone in membrane bioreactor system; A4) Preparing a product for degrading N-acyl homoserine lactone in a membrane bioreactor system.

[0025] The present invention also provides a screening method for the aforementioned quorum induction quenching sterilization, which includes the following steps: inoculating the above-mentioned activated sludge mixed liquid in a container containing a culture medium with C8-HSL as the sole carbon source, the inoculation amount is 5g, and the culture medium with C8-HSL as the sole carbon source is 50mL. Culture at 30°C for 42 days to obtain a fermentation broth. Take 1 mL of the aforementioned fermentation broth and dilute its concentration with sterile water in a gradient manner to 10-1, 10-2, 10-3, 10-4, 10-5, 10-6, 10-7, and 10-8 fermentation broth, then take 100 μL of the diluted fermentation broth of each concentration gradient and evenly spread it on an LB solid plate, culture at 30°C for 48h, select the aforementioned concentration gradient culture medium with the best growth potential, select single colonies of different morphologies from it, and perform streaking culture on the LB solid culture medium. The culture conditions are cultured at 30°C for 48h to obtain M22.

[0026] Optionally, in S1, S2, and S3, the AHL includes C6-HSL and C8-HSL.

[0027] Optionally, in S1, S2, and S3, in the culture medium with AHL as the sole carbon source, the AHL concentrations are 5 μM, 10 μM, 20 μM, 40 μM, 80 μM, and 160 μM, respectively.

[0028] Optionally, in S4, the step of diluting the fermentation broth with sterile water, and then spreading the diluted fermentation broth on LB agar to isolate multiple single colonies specifically includes: Take 1 mL of the fermentation broth with AHL as the sole carbon source, dilute it with sterile water to 10-1, 10-2, 10-3, 10-4, 10-5, 10-6, 10-7, 10-8, and then take 100 μL of the diluted fermentation broth of each concentration gradient and spread it evenly on the LB solid plate and culture at 30 ° C. Pick single colonies with different colony morphologies on the plate, and repeatedly streak them on the LB solid plate for purification until a single colony is isolated.

[0029] Optionally, in S5, the steps of performing QS function identification and culturing on the isolated colonies, adding signal molecules, comparing quenching effects, calculating the quenching rate according to the degradation amount of the signal molecules, and screening new bacteria for quorum sensing quenching specifically include: inoculating the screened single colony into LB liquid culture medium for 24 hours, adding 50 μM AHL signal molecules, and taking 1 mL of bacterial solution after 24 hours to determine the remaining concentration of the signal molecules therein using a reporter strain. The quenching rate is calculated according to the degradation amount of the signal molecules by the strain within 24 hours.

[0030] Optionally, the reporter strain is Bacillus violaceus CV026.

[0031] The advantages of the present invention are that it provides a new quorum sensing quenching bacterium, supplements the existing QQ bacteria species resources, and can degrade signal molecules in the membrane bioreactor system, effectively combating biological contamination of the membrane, which is of great significance to the development of the sewage treatment field.

[0032] Collection Instructions Strain name: Stenotrophomonas maltophilia Latin name: Stenotrophomonas maltophilia Strain ID: M22 Depository: China National Microbiological Culture Collection Administration General Microbiology Center Abbreviation of depository institution: CGMCC Address: No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing Deposit date: September 26, 2024 The registration number of the Collection Center is: CGMCC No.32084. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 For the initial screening of bacteria in MBR sludge mixed liquor.

[0034] Figure 2 The single colony strains are M1 to M22. The first row from top to bottom are M1 to M6, the second row from top to bottom are M7 to M12, the third row from top to bottom are M14 to M17 and M19, and the fourth row from top to bottom are M21 and M22.

[0035] Figure 3 The results show that the extracts of strains M21-M23 from MBR sludge mixed liquor, methanol and ultrapure water inhibited the production of violacein.

[0036] Figure 4 This is a phylogenetic tree constructed based on the 16S rRNA gene sequence of strain M22 and its closely related species.

[0037] Figure 5This is the effect of crude extracts from the supernatant of M22 strain on the growth of Bacillus violaceus Cv026.

[0038] Figure 6 This is the effect of different concentrations of strain M22 extract on the production of violacein from Bacillus violaceus Cv026. DETAILED DESCRIPTION

[0039] The present invention is further described in detail below in conjunction with specific embodiments, and the examples provided are only for illustrating the present invention, rather than for limiting the scope of the present invention. The examples provided below can be used as a guide for further improvements by those of ordinary skill in the art, and do not constitute a limitation of the present invention in any way.

[0040] The experimental methods in the following examples, unless otherwise specified, are all conventional methods, and are performed according to the techniques or conditions described in the literature in the field or according to the product instructions. The materials, reagents, etc. used in the following examples, unless otherwise specified, can all be obtained from commercial channels.

[0041] The following examples used GraphPad Prism 8 statistical software to process the data, and the experimental results were expressed as mean ± standard deviation. One-way ANOVA test was used, and P < 0.05 (*) indicated a significant difference.

[0042] LB medium: 10 g / L tryptone; 5 g / L yeast extract; 5 g / L sodium chloride, 1000 ml sterile water, pH adjusted to about 7.0.

[0043] Mineral salt medium (MSM): ammonium sulfate 2 g / L; magnesium sulfate heptahydrate 0.2 g / L; calcium chloride dihydrate 0.01 g / L; ferrous sulfate heptahydrate 0.001 g / L; disodium hydrogen phosphate dodecahydrate 1.5 g / L; sodium dihydrogen phosphate 1.5 g / L, sterile water 1000ml, pH 6.5.

[0044] The above culture medium was sterilized at 121℃ for 20 minutes before use. If the corresponding solid culture medium is required, add 1.5% (w / ν) agar powder.

[0045] Bacillus violaceus Cv026 was obtained from Baosai Plasmid Strain Resource Company.

[0046] C8-HSL: purchased from Shanghai MacLean Biochemical Technology Co., Ltd., product number N922680-25mg.

[0047] Example 1. Isolation, identification and rescreening of strains 1. Strain Isolation and Screening 1. Strain Isolation The culture medium formula with C8-HSL as the sole carbon source is: 2 g ammonium sulfate, 0.2 g magnesium sulfate heptahydrate, 0.01 g calcium chloride dihydrate, 0.001 g ferrous sulfate heptahydrate, 1.5 g disodium hydrogen phosphate dodecahydrate, 1.5 g sodium dihydrogen phosphate, pH 6.5, and the balance is deionized water.

[0048] The activated sludge sample was taken from the small-scale MBR equipment (equipment name: membrane bioreactor, the membrane bioreactor is a customized model, no model) in the 1310 laboratory of Minzu University of China in Beijing in June 2024. The activated sludge was resuspended by adding 0.05% NaCl solution to obtain an activated sludge mixed liquor, and the content of activated sludge in the activated sludge mixed liquor was between 7901.14 ± 527.11 mg / L. The activated sludge mixed liquor was separated according to the following operations: The above activated sludge mixture was inoculated into a container containing a culture medium with C8-HSL as the sole carbon source, with an inoculation amount of 5 g, of which 50 mL was the culture medium with C8-HSL as the sole carbon source. The culture was cultured at 30°C for 42 days to obtain a fermentation broth. 1 mL of the above fermentation broth was taken and diluted with sterile water to a concentration of 10 -1 , 10 -2 , 10 -3 , 10 -4 , 10 -5 , 10 -6 , 10 -7 , 10 -8 Then, 100 μL of the diluted fermentation broth of each concentration gradient was evenly spread on the LB solid plate, and cultured at 30°C for 48 h. The concentration gradient medium with the best growth potential ( Figure 1 ), single colonies of different morphologies were selected and streaked on LB solid medium at 30°C for 48h. Figure 2 As shown, the single colony obtained was named M22.

[0049] 2. Strain screening The purified 23 single colonies were inoculated into LB liquid culture medium, cultured at 28°C for 1 day, and the fermentation broth of 23 strains of bacteria was obtained. The above fermentation broth was used to extract the crude supernatant extract using ethyl acetate, and the specific operation was as follows: 2mL of glycerol bacterial solution was inoculated into 100mL of LB liquid culture medium, placed in a constant temperature incubator at 28°C, and cultured at 160rpm for 24h, then the culture broth was centrifuged for 10min at 4°C and 6000xg, the supernatant was filtered through a 0.22μm filter membrane and mixed with an equal volume of ethyl acetate, fully shaken, and allowed to stand for 10min, the upper extract was collected, and the above steps were repeated 3 times, all the collected extracts were evaporated to dryness at 40°C by a rotary evaporator, the extract was dissolved in 70% methanol and filtered through a 0.22μm filter membrane to obtain a crude supernatant extract, and the crude supernatant extracts of the above 23 strains of bacteria were obtained.

[0050] Purple Bacillus Cv026 was inoculated on a plate containing LB liquid culture medium (formula: 10 g / L tryptone, 5 g / L yeast extract, 10 g / L sodium chloride, 1000mL distilled water) containing 0.2mmol / L C8-HSL solution and 100μL 50mg / L kanamycin solution. After culturing at 28℃ for 24h, a hole with a diameter of 6mm was punched on the above plate using a hole puncher (5 holes were punched on each plate). The crude supernatant extracts of the above 23 strains were injected into the above holes, 0.5mL per well. If the strain has the ability to inhibit quorum sensing, a yellow halo will appear around the round hole. The wells injected with an equal amount of methanol or sterile water were used as controls.

[0051] Since the purple bacillus Cv026 does not produce AHLs signal molecules by itself, only when exogenous AHLs signal molecules appear, such as the signal molecule C8-HSL, the CviR gene of the purple bacillus Cv026 is expressed and purple bacteriocin is secreted, causing the plate inoculated with purple bacillus Cv026 to appear purple. Figure 3 It can be seen that the circles where methanol and sterile water (control group) were injected were purple, indicating that they had no quorum sensing inhibition ability, while obvious yellow halos appeared around the circles where the crude extract of the supernatant of the M22 strain was injected, indicating that this strain may have quorum sensing quenching ability, indicating that its quorum sensing quenching activity may be extremely strong.

[0052] 3. Species identification of quorum quenching bacteria M22 DNA of the M22 strain was extracted and PCR amplified using the following primers: 27F primer (5′-AGAGTTTGATCMTGGCTCAG-3′) and 1492R (5′-TACGGYTACCTTGTTACGACTT-3′).

[0053] The amplified product of the M22 strain was sequenced to obtain the 16S rRNA gene sequence of the M22 strain.

[0054] 16S rRNA gene of M22 (SEQ ID NO: 1):

[0055] The 16S rRNA gene sequence of strain M22 was compared with that of Stenotrophomonas maltophilia strain LI has the highest homology, reaching 99.64% ( Figure 2 ). The biological phylogenetic tree of strain M22 is as follows Figure 6 As shown. Strain M22 and Stenotrophomonas maltophilia The relationship between strain LI and strain LI is the closest, and the evolutionary tree shows that they belong to the same large branch. Combined with the sequencing results of strain M22, it can be identified as Stenotrophomonas maltophilia (Stereotrophomonas maltophilia).

[0056] Based on the above morphological characteristics, physiological and biochemical characteristics, and 16S rRNA gene analysis results, strain M22 was identified as Stenotrophomonas maltophilia ( Stenotrophomonas maltophilia ). It was deposited on September 26, 2024 in the General Microbiology Center of China Microorganism Culture Collection (referred to as CGMCC; address: No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, Institute of Microbiology, Chinese Academy of Sciences; Postal Code: 100101), with the deposit number CGMCC No.32084.

[0057] 2. Results of population quenching sterilization rescreening Although Chromobacterium violaceum Cv026 cannot synthesize signal molecules by itself, it can activate the expression of quorum sensing-related genes and secrete violacein in the presence of exogenous signal molecules, making the plate appear purple (references: McClean, KayH., et al. "Quorum Sensing and Chromobacterium violaceum: Exploitation ofViolacein Production and Inhibition for the Detection of N-Acyl HomoserineLactones." Microbiology, vol. 143, 1997, pp. 3703-3711. SGM, https: / / doi.org / 10.1099 / 00221287-143-12-3703.;Steindler, Laura, and Vittorio Venturi. "Detection of Quorum-Sensing N-Acyl Homoserine Lactone Signal Molecules byBacterial Biosensors." FEMS Microbiology Letters, vol. 266, no. 1, 2007, pp.1-9. Oxford University Press, https: / / doi.org / 10.1111 / j.1574-6968.2006.00501.x.). If the strain can reduce the concentration of AHL signal molecules (that is, the metabolites of the target strain can degrade AHL signal molecules), the amount of violacein secreted by Bacillus purpurogenus Cv026 will decrease. However, the metabolites of the target strain may also reduce the concentration of violacein by inhibiting the growth of Bacillus purpurogenus Cv026. Therefore, it is necessary to re-screen the quorum-sensing quenching bacteria by detecting the effect of M22 extract on the growth of Bacillus purpurogenus Cv026 and the effect of different concentrations of extracts on the concentration of violacein secreted by Bacillus purpurogenus Cv026.

[0058] Extraction method of crude supernatant extract of M22: inoculate M22 into LB liquid culture medium and culture at 28 ℃ for 1 day to obtain the fermentation liquid of M22 strain. Use ethyl acetate to extract the crude supernatant extract of the fermentation liquid. The specific operation is as follows: inoculate 2mL of glycerol bacterial liquid into 100mL of LB liquid culture medium, place it in a constant temperature incubator at 28℃, shake and culture at 160rpm for 24h, then centrifuge the culture liquid at 4℃ and 6000xg for 10min, take the supernatant and pass it through a 0.22μm filter membrane, mix it with an equal volume of ethyl acetate, shake it thoroughly, let it stand for 10min, collect the upper extract, and repeat the above steps 3 times. The collected M22 extract was evaporated to dryness at 40℃ on a rotary evaporator, the extract was dissolved in 70% methanol and passed through a 0.22μm filter membrane to obtain a crude supernatant extract, and the crude supernatant extract of M22 was obtained. The crude supernatant extract of M22 was prepared as a working solution. The contents of crude extracts of M22 supernatant in the working solution were 0 mg / L, 50 mg / L, 100 mg / L, 250 mg / L and 500 mg / L, respectively. Working solution preparation method: M22 supernatant crude extracts were mixed with C8-HSL (0.2mmol / L) to make the final contents of M22 supernatant crude extracts in the working solution 0 mg / L, 50 mg / L, 100 mg / L, 250 mg / L, 500 mg / L (three parallels in each group).

[0059] The purple bacillus Cv026 was inoculated on a plate containing a culture medium (formula: 10 g Tryptone, 5 g Yeast Extract, 10 g NaCl) containing 0.2 mmol / L C8-HSL solution and 100 μL 50 mg / L kanamycin solution. After culturing at 28°C for 24 h, a hole was punched in the plate and the supernatant extract was added to the hole. The plate was placed in a constant temperature incubator and cultured at 28°C for 24 h. The above plates were processed and the OD values ​​of the supernatant crude extracts of 0 / 50 / 100 / 250 / 500 mg / L were calculated. 600nm The value was used to evaluate the effect of the supernatant crude extract on the growth of purple bacillus Cv026. The specific method was as follows: purple bacillus Cv026 was inoculated into LB liquid culture medium and cultured in a constant temperature shaking box at 28°C and 160rpm until OD600≈1.0. The purple bacillus Cv026 bacterial solution was diluted 1000 times with sterilized LB culture medium, and the supernatant crude extract with a final concentration of 0 / 50 / 100 / 250 / 500mg·mL–1 was added (three parallels in each group), and the supernatant crude extract was cultured at 28°C and 160rpm. The OD600 absorbance was measured every 2h until OD600≈1.0 to detect the effect of the extract on the growth of purple bacillus Cv026.

[0060] At the same time, the purple bacterium production of the above-mentioned plate was measured. The specific method was as follows: purple bacillus Cv026 was inoculated into LB liquid culture medium and cultured in a constant temperature shaking box at 28°C and 160 rpm until OD 600 ≈1.0. Add 0.2mmol·L –1 After C8-HSL, mix well and add crude supernatant extracts at final concentrations of 0 / 50 / 100 / 250 / 500 mg / L (three parallels per group); blank control group: 0 mmol·L –1 C8-HSL, 0mg·mL –1 The supernatant was crude extract; cultured at 30°C, 180 rpm with shaking for 20 h.

[0061] The cultured purple bacillus Cv026 was placed in a sterile centrifuge tube and centrifuged at 8000 rpm for 10 min at room temperature. The supernatant was discarded and an equal volume of DMSO was added. The tube was fully vortexed for 1 min to dissolve the purple bacterin. The tube was centrifuged again under the same conditions. 300 μL of the supernatant was taken and plated on a 96-well plate to measure the OD 585 . Used to evaluate the effect of the extract on the production of violacein from Bacillus violaceus Cv026.

[0062] Effects of different concentrations of crude extracts from M22 supernatant on the growth of Bacillus violaceus Cv026 Figure 5 As shown, after adding 0-500 mg / L supernatant crude extract, the growth of Bacillus violaceus Cv026 did not change significantly, which indicates that the above four strains of preliminary screening bacteria do not inhibit the secretion of violacein by inhibiting the growth of Bacillus violaceus Cv026.

[0063] Effects of different concentrations of M22 supernatant extract on the yield of violacein Figure 6 As shown, the yield of violacein decreased with the increase of the amount of crude extract added to the strain supernatant, indicating that the strain M22 inhibited the production of violacein, and the intensity of inhibition was obviously dose-dependent, which was consistent with the above-mentioned plate model screening results.

[0064] In summary, M22 reduces the production of violacein by interfering with the QS system of Bacillus violaceus (i.e., inhibiting the expression of quorum sensing-related genes).

[0065] The present invention has been described in detail above. For those skilled in the art, without departing from the purpose and scope of the present invention, and without the need to carry out unnecessary experimental conditions, the present invention can be implemented in a wide range under equivalent parameters, concentrations and conditions. Although the present invention provides specific embodiments, it should be understood that the present invention can be further improved. In a word, according to the principles of the present invention, the application is intended to include any changes, uses or improvements to the present invention, including departure from the disclosed scope in the application, and changes made with conventional techniques known in the art.

Claims

1. A oligotrophic monocytogenes, characterized in that The oligotrophic mononas is oligotrophic mononas maltophilia ( Stenotrophomonas maltophilia ), its strain number is M22, and its registration number at the General Microbiology Center of China Culture Collection Administration is: CGMCC No.32084.

2. The culture of Stenotrophomonas maltophilia according to claim 1, which is obtained by culturing the Stenotrophomonas maltophilia according to claim 1 in a microbial culture medium.

3. A bacterial agent, characterized in that The bacterial agent contains the Stenotrophomonas maltophilia described in claim 1 or / and the metabolites of the Stenotrophomonas maltophilia described in claim 1 or / and the culture described in claim 2.

4. Any of the following uses of the Stenotrophomonas maltophilia described in claim 1: A1) Quorum sensing of inhibitory strains; A2) preparing products that inhibit quorum sensing of strains; A3) Degradation of N-acyl homoserine lactone in membrane bioreactor system; A4) Preparing a product for degrading N-acyl homoserine lactone in a membrane bioreactor system.

5. Any of the following uses of the metabolite of Stenotrophomonas maltophilia described in claim 1: A1) Quorum sensing of inhibitory strains; A2) preparing products that inhibit quorum sensing of strains; A3) Degradation of N-acyl homoserine lactone in membrane bioreactor system; A4) Preparing a product for degrading N-acyl homoserine lactone in a membrane bioreactor system.

6. Any of the following uses of the culture according to claim 2: A1) Quorum sensing of inhibitory strains; A2) preparing products that inhibit quorum sensing of strains; A3) Degradation of N-acyl homoserine lactone in membrane bioreactor system; A4) Preparing a product for degrading N-acyl homoserine lactone in a membrane bioreactor system.

7. Any of the following uses of the bacterial agent according to claim 3: A1) Quorum sensing of inhibitory strains; A2) preparing products that inhibit quorum sensing of strains; A3) Degradation of N-acyl homoserine lactone in membrane bioreactor system; A4) Preparing a product for degrading N-acyl homoserine lactone in a membrane bioreactor system.

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