Bifidobacterium breve with high efficiency of degrading dodecanoyl-l-homoserine lactone and application thereof

Abstract

The application discloses a kind of high-efficiency degradation dodecanoyl-L-homoserine lactone short bifidobacterium and its application, characterized in that the strain classification is named short bifidobacterium Bifidobacterium breve , preservation number is CGMCC No.39402, also provide the application of above-mentioned strain in preparation for degrading N-hexanoyl-L-homoserine lactone product, production indole-3-lactic acid product, conversion linoleic acid into conjugated linoleic acid product, production lactic acid and / or acetic acid product, bacteriostatic agent, antioxidant and pancreatic lipase inhibitor;Advantages are that the strain can efficiently degrade HSL, and have inhibitory effect on escherichia coli and staphylococcus aureus;Can efficiently utilize tryptophan to produce indole-3-lactic acid, simultaneously high-yield lactic acid and acetic acid;Can utilize linoleic acid substrate to produce conjugated linoleic acid, and can effectively inhibit pancreatic lipase activity and have good antioxidant performance.

Description

Technical Field

[0001] This invention relates to Bifidobacterium breve, and more particularly to a highly efficient Bifidobacterium breve that degrades dodecanoyl-L-homoserine lactone and its applications. Background Technology

[0002] Creatine is a key energy metabolism substance in the human body, mainly absorbed from the intestine and transported to skeletal muscle via creatine transporter protein (CRT), providing a rapid energy supply for muscle contraction. Gram-negative bacteria in the intestine can produce an important quorum sensing signaling molecule—dodecanoyl-L-homoserine lactone (HSL). HSL can significantly inhibit the absorption of creatine by intestinal epithelial cells, primarily through downregulating the expression and / or function of CRT, thus hindering the transport of creatine from the intestine to the bloodstream. Studies have shown that lactic acid bacteria significantly reduce HSL levels by regulating the intestinal microenvironment. This regulatory effect effectively removes the restriction on creatine transport by host intestinal cells, promoting creatine circulation. Therefore, effectively clearing or degrading HSL in the intestinal environment, thereby relieving its inhibitory effect on CRT, has become an important research direction for improving creatine absorption and utilization efficiency.

[0003] Lactic acid bacteria play a vital role in regulating immunity, maintaining gut health, and optimizing lipid metabolism. Some Bifidobacteria can metabolize tryptophan to produce indole-3-lactic acid (ILA), activating the aryl hydrocarbon receptor (AhR) pathway, regulating intestinal immune responses, promoting the production of anti-inflammatory factors, and improving gut microbiota balance. They can also produce short-chain fatty acids such as lactic acid and acetic acid, enhancing intestinal barrier function and participating in energy metabolism regulation. In lipid management, lactic acid bacteria have the ability to convert linoleic acid into conjugated linoleic acid (CLA), which can inhibit fat accumulation and improve blood lipid levels. Simultaneously, lactic acid bacteria can reduce dietary fat absorption by inhibiting pancreatic lipase activity, thus improving the body's lipid metabolism. Therefore, probiotics with multiple functions, including HSL degradation, immune regulation, lipid metabolism optimization, and antioxidant effects, have significant application potential in promoting creatine absorption, improving muscle function, and enhancing overall metabolic health. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a highly efficient Bifidobacterium breve that degrades dodecanoyl-L-homoserine lactone and its applications in products that promote creatine absorption, improve muscle function, relieve sarcopenia, regulate intestinal microecology, enhance immune function, and optimize lipid metabolism.

[0005] The technical solution adopted by this invention to solve the above-mentioned technical problem is: a short-lived Bifidobacterium that efficiently degrades dodecanoyl-L-homoserine lactone, wherein the short-lived Bifidobacterium is classified and named as Bifidobacterium breve (Bifidobacterium breve). Bifidobacterium breveThe strain QS692, with accession number CGMCC No.39402, was deposited on June 16, 2026. The depository is the China General Microbiological Culture Collection Center, located at No.3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, China, Institute of Microbiology, Chinese Academy of Sciences.

[0006] The present invention also provides the use of the above-mentioned Bifidobacterium breve in the preparation of products for degrading N-hexanoyl-L-homoserine lactone (HSL), wherein the Bifidobacterium breve is anaerobically cultured in a medium containing HSL.

[0007] The present invention also provides the application of the above-mentioned Bifidobacterium breve in the preparation of products for the production of indole-3-lactic acid, wherein the Bifidobacterium breve is metabolized to produce indole-3-lactic acid after anaerobic fermentation in a tryptophan-containing culture medium.

[0008] The present invention also provides the application of the above-mentioned Bifidobacterium breve in the preparation of products for converting linoleic acid to conjugated linoleic acid.

[0009] The present invention also provides the use of the above-mentioned Bifidobacterium breve in the preparation of products for the production of lactic acid and / or acetic acid.

[0010] The present invention also provides the use of the above-mentioned Bifidobacterium breve in the preparation of antibacterial agents for inhibiting Staphylococcus aureus and / or Escherichia coli.

[0011] The present invention also provides the application of the above-mentioned Bifidobacterium breve in the preparation of antioxidants, wherein the antioxidants are superoxide anion scavengers, ABTS free radical scavengers and / or DPPH free radical scavengers.

[0012] The present invention also provides the application of the above-mentioned Bifidobacterium breve in the preparation of pancreatic lipase inhibitors.

[0013] The present invention also provides a microbial preparation containing the above-mentioned Bifidobacterium breve, wherein the microbial preparation is selected from Bifidobacterium breve suspension, fermentation supernatant, lyophilized bacterial powder or a combination thereof.

[0014] The present invention also provides the application of the above-mentioned Bifidobacterium breve in the preparation of products, wherein the application is at least one of the following: in the preparation of products that promote creatine absorption, in the preparation of products that improve muscle function, in the preparation of products that alleviate sarcopenia, in the preparation of products that regulate intestinal microecology, and in the preparation of products that optimize lipid metabolism.

[0015] Compared with existing technologies, the advantages of this invention are as follows: This invention discloses a highly efficient Bifidobacterium breve for degrading dodecanoyl-L-homoserine lactone and its application. This Bifidobacterium breve QS692 can efficiently degrade dodecanoyl-L-homoserine lactone (HSL). After fermentation for 48 hours in MRS medium containing a final concentration of 0.3 mM HSL and supplemented with 0.5 wt% L-cysteine ​​hydrochloride, 91.89% of HSL can be effectively degraded. Degradation of HSL can relieve its inhibitory effect on creatine transport proteins, thereby promoting intestinal absorption and muscle utilization of creatine. It plays an indispensable role in promoting creatine absorption, improving muscle function, and alleviating sarcopenia. This strain can efficiently utilize tryptophan to metabolize indole-3-lactic acid. Fermentation for 48 hours in MRS medium containing 2 g / L tryptophan and 0.5 wt% L-cysteine ​​hydrochloride yielded an indole-3-lactic acid content of 77.4 μg / mL, while also producing high levels of lactic acid and acetic acid, at 3.69 g / L and 4.48 g / L, respectively. It achieved a 40.88% conversion rate of linoleic acid to conjugated linoleic acid, and its bacterial suspension inhibited pancreatic lipase activity by 74.33%, demonstrating multiple synergistic functions including regulating intestinal immunity, enhancing the intestinal barrier, and optimizing lipid metabolism. Furthermore, this strain exhibits inhibitory effects against *Escherichia coli* and *Staphylococcus aureus*; it also possesses scavenging abilities against superoxide anions, DPPH radicals, and ABTS radicals, exhibiting excellent antioxidant properties. Attached Figure Description

[0016] Figure 1 This is a colony morphology diagram of Bifidobacterium breve QS692; Figure 2 The images show the liquid chromatograms of Bifidobacterium breve QS692 before and after degradation of HSL. The blue line (thin line) represents the peak area of ​​HSL in the sample solution before inoculation with the strain, and the green line (thick line) represents the peak area of ​​HSL in the sample solution after inoculation with the strain and culturing in medium containing 0.3 mg / mL HSL for 48 h. Figure 3 Liquid chromatography peaks representing the ability of Bifidobacterium brevis QS692 to produce indole-3-lactic acid; Figure 4 The standard curve for indole-3-lactic acid; Figure 5 The standard curve for conjugated linoleic acid; Figure 6 This is a standard curve for lactic acid. Figure 7 This is the standard curve for acetic acid. Detailed Implementation

[0017] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0018] Specific Implementation Example 1: Isolation and Identification of Strains.

[0019] 1. Strains Isolation Dissolve 1g of fecal matter from a centenarian in a centrifuge tube containing 9mL of sterile saline solution, vortex to mix, and set aside. Dilute to 10⁻⁶ using a serial dilution method. -6 From 10 respectively -4 10 -5 10 -6 Three gradients of 100 μL were evenly spread onto MRS solid medium supplemented with 0.5 wt% L-cysteine ​​hydrochloride. The culture dishes were placed in an anaerobic workstation at 37°C and incubated for 48 hours. Colony morphology was observed and recorded. Single colonies were picked up using an inoculation loop and streaked onto MRS solid medium supplemented with 0.5 wt% L-cysteine ​​hydrochloride. The culture was then anaerobic at 37°C for 48 hours to obtain pure colonies. The pure colonies obtained from the plates were inoculated into MRS liquid medium supplemented with 0.5 wt% L-cysteine ​​hydrochloride and anaerobic at 37°C for 16-18 hours. The pure strain was then mixed with a 50% glycerol solution in an equal proportion and stored at -80°C. A total of 110 lactic acid bacteria strains were screened from fecal samples of long-lived elderly individuals. Among them, strain QS692 showed significant advantages in antioxidant and acid-resistant properties. Therefore, strain QS692 was identified as the key strain for this experiment.

[0020] 2. Strain identification Genomic DNA was extracted from the strain obtained in step 1, and then amplified and sequenced using the universal 16S rRNA primers 27F and 1492R to identify the strain species. The primer sequences of the universal 16S rRNA primers 27F and 1492R are as follows: 27F: 5'-AGAGTTTGATCCTGGCTCAG-3'; 1492R: 5'-GGTTACCTTGTTACGACTT-3'; PCR system components: 1 μL DNA template, 1 μL 27F, 1 μL 1492R, 22 μL sterile water, 2×Taq PCR Master Mix (PCR premix).

[0021] The PCR program was as follows: pre-denaturation at 95℃ for 10 min, denaturation at 95℃ for 30 s, annealing at 55℃ for 30 s, extension at 72℃ for 30 s, for 30 cycles; final extension at 72℃ for 10 min. The amplified PCR product was removed, and 1.5-2 μL of the PCR product was added to an agarose gel. The electrophoresis apparatus voltage was set to 99-100V, and the gel was run for 20-30 min. After completion, the gel was removed, and the DNA bands were observed using a gel imaging system, revealing the target fragment length to be 1500 bp.

[0022] 16S rRNA sequencing: The validated PCR products were sent to Shanghai Saiheng Biotechnology Co., Ltd. for sequencing. The obtained 16S rRNA sequences were compared and analyzed on the NCBI website. Homology comparisons were performed with the sequencing information of known strains to identify the strains. The results showed that the colony morphology of strain QS692, screened from the feces of centenarians, was as follows: Figure 1 As shown; strain QS692 was identified as Bifidobacterium breve, with the sequence shown below:

[0023] This strain is currently deposited at the China General Microbiological Culture Collection Center, and its classification name is Bifidobacterium breve (Bifidobacterium breve). Bifidobacterium breve The strain QS692, with accession number CGMCC No.39402, was deposited on June 16, 2026. The deposit address is No.3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, China, Institute of Microbiology, Chinese Academy of Sciences, and the depositary institution is the China General Microbiological Culture Collection Center.

[0024] Specific Example 2: Analysis of the ability of Bifidobacterium breve QS692 to degrade HSL.

[0025] 1. Preparation of Bifidobacterium breve QS692 seed culture The Bifidobacterium breve QS692, stored at -80℃, was taken out and inoculated into MRS liquid medium supplemented with 0.5wt% L-cysteine ​​hydrochloride at an inoculation rate of 2% (v / v) for 3 generations of activation culture.

[0026] 2. Determination of the HSL degradation ability of Bifidobacterium breve QS692 (1) Seed culture was inoculated into 10 mL of MRS medium containing 3 mM HSL and 0.5 wt% L-cysteine ​​hydrochloride at a 2% (v / v) inoculation rate. The culture was anaerobic at 37 °C for 48 h, repeated three times. The culture was centrifuged at 8000 rpm at 4 °C, and the supernatant was collected. 3 mL of the supernatant was vortexed vigorously with an equal volume of ethyl acetate for 2 minutes to fully extract the HSL into the organic phase. After standing and separating the layers, the upper organic phase was carefully aspirated and transferred to a new centrifuge tube. The extraction was repeated twice, and all organic phases were combined and subjected to nitrogen blowing at room temperature to obtain the sample to be tested. The sample was redissolved in 1 mL of chromatographic grade methanol and vortexed vigorously for 1 minute. The redissolved sample was filtered through a 0.22 μm microporous membrane and transferred to an HPLC vial for HPLC analysis.

[0027] (2) The conditions for high performance liquid chromatography (HPLC) analysis included: the HPLC instrument was an Agilent 1260 Infinity. Chromatographic separation was performed using a ZORBAX SB-Aq 4.6×150mm 3.5-Micron chromatogram, with a detection wavelength of 210nm. The organic phase was set as acetonitrile at a ratio of 65%, and the inorganic phase was set as ultrapure water at a ratio of 35%. The column temperature was 30℃, the injection volume was 10μL, and the flow rate was 0.25mL / min.

[0028] (3) The peak area of ​​HSL was determined using the external standard method. The elution time of the HSL standard was 13.686 min. Figure 2As shown, the peak areas of HSL in the solution before and after inoculation with *Bifidobacterium breve* QS692 can be obtained. The peak area of ​​HSL in the sample solution without inoculation with *Bifidobacterium breve* QS692 is 1565.809. After inoculating *Bifidobacterium breve* QS692 into medium containing a final concentration of 0.3 mM HSL and culturing for 48 h, the peak area of ​​HSL in the sample solution is 126.964. The HSL degradation ability of the strain was calculated using the following formula. Therefore, the HSL degradation ability of *Bifidobacterium breve* QS692 is 91.89%.

[0029] HSL degradation capacity (%) = (AB) / A × 100, where A is the peak area of ​​HSL content in the sample solution when the strain is not inoculated; B is the peak area of ​​HSL content in the sample solution after the strain is inoculated into medium containing 0.3 mM HSL and cultured for 48 h.

[0030] Specific Example 3: Analysis of the ability of Bifidobacterium breve QS692 to produce indole-3-lactic acid.

[0031] 1. Preparation of Bifidobacterium breve QS692 seed culture The Bifidobacterium breve QS692, stored at -80℃, was taken out and inoculated into MRS liquid medium supplemented with 0.5wt% L-cysteine ​​hydrochloride at an inoculation rate of 2% (v / v) for 3 generations of activation culture.

[0032] 2. Determination of indole-3-lactic acid, a tryptophan metabolite from Bifidobacterium breve QS692 (1) Seed culture was inoculated into 10 mL of MRS medium containing 2 g / L tryptophan and 0.5 wt% L-cysteine ​​hydrochloride at a 2% (v / v) inoculation rate. The culture was anaerobic at 37 °C for 48 h, and repeated 3 times. The culture medium was centrifuged at 8000 rpm at 4 °C, and the supernatant was collected. The supernatant was mixed with methanol pre-cooled at -20 °C at a ratio of 1:4, treated at -20 °C for 30 min, and centrifuged at 12000 rpm at 4 °C to collect the supernatant. Nitrogen blowing was performed at room temperature to obtain the sample to be tested.

[0033] (2) Redissolve the sample in 1 mL of chromatographic grade methanol and vortex vigorously for 1 minute. Filter the redissolved sample through a 0.22 μm microporous membrane and transfer it to an HPLC vial for high-performance liquid chromatography analysis. The results are as follows: Figure 3As shown. The conditions for high-performance liquid chromatography (HPLC) analysis included: an Agilent 1260 Infinity HPLC system; a ZORBAX SB-Aq 4.6×150mm 3.5-Micron chromatograph for separation; a wavelength of 280 nm; mobile phases A (0.1% formic acid aqueous solution) and B (100% acetonitrile); an injection volume of 10 μL; and a flow rate of 1 mL / min. The gradient elution program was as follows: Table 1 Gradient elution program

[0034] (3) The peak area of ​​indole-3-lactic acid at different concentrations was determined using the external standard method. A standard curve was obtained by plotting the indole-3-lactic acid concentration (x) and peak area (y), as follows: Figure 4 As shown, y = 13.428x - 29.039, R² = 0.9968. From Figure 3 The peak area (y) of Bifidobacterium breve QS692 was obtained, and the concentration of indole-3-lactic acid in the fermentation supernatant of Bifidobacterium breve QS692 was calculated to be 77.4 μg / mL.

[0035] Specific Example 4: Analysis of the ability of Bifidobacterium breve QS692 to convert linoleic acid into conjugated linoleic acid.

[0036] 1. Preparation of Bifidobacterium breve QS692 seed culture The Bifidobacterium breve QS692, stored at -80℃, was taken out and inoculated into MRS liquid medium supplemented with 0.5wt% L-cysteine ​​hydrochloride at an inoculation rate of 2% (v / v) for 3 generations of activation culture.

[0037] 2. Plotting the standard curve of conjugated linoleic acid (CLA) Weigh 100 mg of CLA standard and dissolve it in 10 mL of n-hexane solution. After thorough shaking and mixing, obtain a 10000 mg / L CLA standard stock solution and store it at -20°C protected from light. Dilute the CLA standard stock solution with n-hexane solution to prepare CLA standard solutions of different concentrations (1, 2, 4, 5, 10, and 12.5 mg / L). Plot a standard curve with CLA mass concentration on the x-axis and absorbance on the y-axis. The results are shown below. Figure 5 As shown.

[0038] 3. Preparation of the substrate linoleic acid (LA) Weigh 1500 mg LA and 1000 mg Tween-80, dissolve them in water, and bring the volume to 50 mL. After emulsification by stirring thoroughly with a high-speed emulsifying homogenizer, filter the mixture through a 0.22 μm sterile filter membrane for sterilization, and store it at -20℃ protected from light.

[0039] 4. The ability of Bifidobacterium breve QS692 to convert linoleic acid into conjugated linoleic acid. (1) Seed culture was inoculated into 10 mL of MRS medium containing 50 mg / L L-cysteine ​​hydrochloride at a 2% (v / v) inoculation rate and anaerobic cultured at 37 °C for 48 h, repeated 3 times. The culture medium was centrifuged at 8000 rpm at 4 °C and the supernatant was collected. The supernatant, isopropanol and n-hexane were mixed in a ratio of 3:3:6 (v / v / v), vortexed to mix thoroughly, and allowed to stand to separate into layers. The upper n-hexane layer was transferred to a clean centrifuge tube, and the mixture was repeated 3 times. The absorbance was measured at 233 nm.

[0040] (2) CLA concentration and OD 233nm The linear relationship between the absorbance values ​​is y = 0.0882x - 0.0061, R² = 0.9993. Based on this, it is calculated that *Bifidobacterium breve* QS692 can convert 20.44 mg / L of CLA when the substrate linoleic acid concentration is 50 mg / L. The ability of the strain to convert linoleic acid to conjugated linoleic acid was calculated using the following formula. Therefore, the conversion ability of *Bifidobacterium breve* QS692 to conjugated linoleic acid is 40.88%.

[0041] The ability to convert linoleic acid to conjugated linoleic acid (%) = (AB) / A × 100, where A is the content of the substrate linoleic acid (mg / L); and B is the content of the conjugated linoleic acid generated (mg / L).

[0042] Specific Example 5: Analysis of the ability of Bifidobacterium breve QS692 to produce lactic acid and acetic acid.

[0043] 1. Preparation of Bifidobacterium breve QS692 seed culture The Bifidobacterium breve QS692, stored at -80℃, was taken out and inoculated into MRS liquid medium supplemented with 0.5wt% L-cysteine ​​hydrochloride at an inoculation rate of 2% (v / v) for 3 generations of activation culture.

[0044] 2. Determination of lactic acid and acetic acid content produced by Bifidobacterium breve QS692 (1) Seed culture was inoculated into 10 mL of MRS medium supplemented with 0.5 wt% L-cysteine ​​hydrochloride at an inoculation rate of 2% (v / v). The culture was anaerobic at 37°C for 48 h, and repeated three times. The culture was centrifuged at 4°C and 8000 rpm, the supernatant was collected, and diluted 1000 times to obtain the sample to be tested. Ion chromatography was used for detection. The chromatographic column was AS11-HC, the mobile phase was KOH, the injection volume was 25 μL, and the flow rate was 1.2 mL / min. The gradient elution program was as follows: Table 2 Gradient elution program

[0045] (2) The peak areas of lactic acid and acetic acid standards at different concentrations were determined using the external standard method. A standard curve was obtained by plotting the lactic acid concentration (x) and peak area (y), as follows: Figure 6 As shown, y = 0.1131x - 0.0021, R² = 0.9999. Substituting the values ​​from the standard curve, the lactic acid concentration in the fermentation supernatant of *Bifidobacterium breve* QS692 was calculated to be 3.69 g / L. The standard curve was obtained by plotting the acetic acid concentration (x) and peak area (y), as shown below. Figure 7 As shown, y = 0.1373x + 0.0524, R² = 0.9987. Substituting the values ​​from the standard curve, the acetic acid concentration in the fermentation supernatant of *Bifidobacterium breve* QS692 was calculated to be 4.48 g / L.

[0046] Specific Example 6: Analysis of the antibacterial activity of Bifidobacterium breve QS692 against Staphylococcus aureus ATCC 6538 and Escherichia coli ATCC25922.

[0047] 1. Preparation of pathogenic bacteria suspension Escherichia coli and Staphylococcus aureus were inoculated into LB liquid medium at a rate of 2% (v / v) and incubated at 37°C for 18-24 hours. The bacterial suspensions, after two generations of activation, were then adjusted to an OD concentration using LB liquid medium. 600 It ranges from 0.5 to 0.65.

[0048] 2. Preparation of detection plates Dilute the adjusted concentrations of *Escherichia coli* and *Staphylococcus aureus* at a ratio of 1:10 using LB solid medium cooled to approximately 55°C. After thoroughly mixing the pathogenic bacteria with the LB solid medium, transfer 15 mL to a sterile petri dish containing an Oxford cup, ensuring the bacterial suspension is evenly spread. Once solidified, remove the Oxford cup to prepare the test plate.

[0049] 3. Preparation of Bifidobacterium breve QS692 bacterial culture The Bifidobacterium breve QS692 stored at -80℃ was taken out and inoculated into MRS liquid medium supplemented with 0.5wt% L-cysteine ​​hydrochloride at an inoculation rate of 2% (v / v) for three generations of activation culture. The third generation of Bifidobacterium breve QS692 bacterial culture was collected.

[0050] 4. Antibacterial activity test Add 200 μL of the prepared, third-generation culture of *Bifidobacterium breve* QS692 to the wells of an Oxford cup on a test plate, and then incubate the plate at 37°C for 12–18 h. The antibacterial activity of *Bifidobacterium breve* QS692 is evaluated by measuring the diameter of the inhibition zone. MRS liquid medium containing 0.5 wt% L-cysteine ​​hydrochloride serves as a negative control.

[0051] 5. Evaluation of the antibacterial properties of Bifidobacterium breve QS692 The inhibition zone diameter of Bifidobacterium breve QS692 bacterial suspension against Staphylococcus aureus was 15.5 mm, and the inhibition zone diameter against Escherichia coli was 16.0 mm. This indicates that Bifidobacterium breve QS692 exhibits good antibacterial activity against both Staphylococcus aureus and Escherichia coli.

[0052] Specific Example 7: In vitro antioxidant analysis of Bifidobacterium breve QS692.

[0053] Take out the Bifidobacterium breve QS692 stored at -80℃, inoculate it into MRS liquid medium supplemented with 0.5wt% L-cysteine ​​hydrochloride at a volume ratio of 2%, activate and culture for 3 generations, centrifuge at 8000rpm for 10min at 4℃, and collect the centrifuged cells.

[0054] 1. Evaluation of the superoxide anion scavenging capacity of Bifidobacterium breve QS692 The superoxide anion scavenging capacity of *Bifidobacterium breve* QS692 was determined according to the instructions of the superoxide anion scavenging kit (Grace Biotech, Suzhou), and the result was 21.32%. This indicates that *Bifidobacterium breve* QS692 has good superoxide anion scavenging capacity.

[0055] 2. Evaluation of the ABTS free radical scavenging ability of Bifidobacterium breve QS692 The ABTS free radical scavenging ability of Bifidobacterium breve QS692 was determined according to the instructions of the ABTS free radical scavenging kit (Grace Biotech, Suzhou), and the result was 59.44%. This indicates that Bifidobacterium breve QS692 has good ABTS free radical scavenging ability.

[0056] 3. Evaluation of the DPPH free radical scavenging capacity of Bifidobacterium breve QS692 Following the instructions of the DPPH free radical scavenging kit (Grace Biotech, Suzhou), the DPPH free radical scavenging ability of Bifidobacterium breve QS692 was determined, and the result was 86.00%. This indicates that Bifidobacterium breve QS692 possesses good DPPH free radical scavenging ability.

[0057] Specific Example 8: Analysis of the ability of Bifidobacterium breve QS692 to inhibit pancreatic lipase.

[0058] 1. Preparation of Bifidobacterium breve QS692 seed culture The Bifidobacterium breve QS692, stored at -80℃, was taken out and inoculated into MRS liquid medium supplemented with 0.5wt% L-cysteine ​​hydrochloride at an inoculation rate of 2% (v / v) for 3 generations of activation culture.

[0059] 2. Preparation of Bifidobacterium breve QS692 bacterial suspension Take the prepared 3-generation culture of Bifidobacterium breve QS692 and centrifuge at 8000 rpm for 10 min at 4℃. Collect the centrifuged bacterial cells. Wash the bacterial cells 2-3 times with PBS buffer (under the same centrifugation conditions) to remove residual culture medium. Finally, resuspend the bacterial cells in PBS buffer and vortex thoroughly to disperse them evenly, preparing a bacterial suspension.

[0060] 3. Determination of the ability of Bifidobacterium breve QS692 to inhibit pancreatic lipase 50 μL of *Bifidobacterium breve* QS692 bacterial suspension was added to each well of a 96-well plate, followed by 130 μL of 0.25 mg / mL lipase solution. The plates were incubated at 37 °C for 10 min, then 20 μL of 5.60 μmol / mL p-NPB substrate solution was added, and the plates were incubated at 37 °C for 20 min. The absorbance was then measured at 405 nm, and the inhibitory activity of the strain on pancreatic lipase was calculated using the following formula. The results showed that *Bifidobacterium breve* QS692 inhibited pancreatic lipase by 74.33%.

[0061] The ability to inhibit pancreatic lipase (%) = (1 - (CD) / (AB)) × 100 Wherein, A, B, C and D are the absorbance values ​​of the blank group (no bacterial suspension, but with pancreatic lipase), the blank control group (no bacterial suspension, but no pancreatic lipase), the sample group (with bacterial suspension, but with pancreatic lipase), and the sample control group (with bacterial suspension, but without pancreatic lipase), respectively.

[0062] Specific Example 9: Antibiotic susceptibility test of Bifidobacterium breve QS692.

[0063] 1. Determination of antimicrobial resistance After activating and culturing *Bifidobacterium breve* QS692 for three generations, the bacterial suspension concentration was adjusted with sterile physiological saline. The OD value of the bacterial suspension was measured at 625 nm using a spectrophotometer, ensuring the OD value ranged from 0.16 to 0.20. Following the national food safety standard for the safety evaluation of microbial strains for food use, the antimicrobial resistance of *Bifidobacterium breve* QS692 was determined using the micro-broth dilution method. Seven types of antimicrobial drugs were tested: tetracycline, erythromycin, clindamycin, chloramphenicol, vancomycin, penicillin, and doxycycline.

[0064] 2. Determination of Antimicrobial Resistance Results Referring to the National Food Safety Standard for the Safety Evaluation Procedures of Microbial Strains for Food Use, the drug resistance of Bifidobacterium breve QS692 was evaluated. Bifidobacterium breve QS692 showed sensitivity to seven types of antimicrobial drugs: tetracycline, erythromycin, clindamycin, chloramphenicol, vancomycin, penicillin, and doxycycline, indicating that this strain does not have a significant risk of drug resistance and has good biosafety.

[0065] The foregoing description is not intended to limit the invention, nor is the invention limited to the examples given. Any changes, modifications, additions, or substitutions made by those skilled in the art within the scope of the invention should also be considered within the protection scope of the invention.

Claims

1. A highly efficient Bifidobacterium breve for degrading dodecanoyl-L-homoserine lactone, characterized in that: The short-lived Bifidobacterium is classified and named Bifidobacterium short-lived (Bifidobacterium breve). Bifidobacterium breve (QS692 strain, preservation number CGMCCNo.39402).

2. The use of the Bifidobacterium breve according to claim 1 in the preparation of products for degrading N-hexanoyl-L-homoserine lactone.

3. The use of the Bifidobacterium breve according to claim 1 in the preparation of products for the production of indole-3-lactic acid.

4. The use of the Bifidobacterium breve described in claim 1 in the preparation of a product for converting linoleic acid to conjugated linoleic acid.

5. The use of the Bifidobacterium breve according to claim 1 in the preparation of products for the production of lactic acid and / or acetic acid.

6. The use of the Bifidobacterium breve according to claim 1 in the preparation of an antibacterial agent for inhibiting Staphylococcus aureus and / or Escherichia coli.

7. The application of the *Bifidobacterium breve* according to claim 1 in the preparation of antioxidants, characterized in that, The antioxidants mentioned are superoxide anion scavengers, ABTS free radical scavengers, and / or DPPH free radical scavengers.

8. The use of the Bifidobacterium breve according to claim 1 in the preparation of pancreatic lipase inhibitors.

9. A microbial preparation comprising the *Bifidobacterium breve* as described in claim 1, characterized in that, The microbial preparation is selected from Bifidobacterium breve suspension, fermentation supernatant, freeze-dried bacterial powder, or a combination thereof.

10. The application of the *Bifidobacterium breve* according to claim 1 in the preparation of the product, characterized in that, The application is at least one of the following: preparing products that promote creatine absorption, preparing products that improve muscle function, preparing products that alleviate sarcopenia, preparing products that regulate gut microbiota, and preparing products that optimize lipid metabolism.

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