Phytobacterium plantarum MRS1026.1, fungicide, method for degrading cholesterol and application of phytobacterium plantarum MRS1026.1

Abstract

The invention belongs to the technical field of microorganisms, and particularly relates to a plant lactobacillus, a bacterial agent, a method for degrading cholesterol and application. The invention provides a lactobacillus plantarum MRS1026.1 with the preservation number of CGMCC (China General Microbiological Culture Collection Center) No.34166. The lactobacillus plantarum MRS1026.1 disclosed by the invention is separated from cheese, has oxidation resistance and can be used for degrading cholesterol.

Description

Technical Field

[0001] The invention belongs to the technical field of microorganisms, and particularly relates to a Lactobacillus plantarum MRS1026.1, a bacterial agent, a method for degrading cholesterol and an application thereof. Background Art

[0002] Lowering serum cholesterol levels can reduce the risk of cardiovascular disease (CVD). Currently, treatment for hypercholesterolemia primarily involves dietary adjustments and long-term use of statins. These medications are expensive and often associated with adverse reactions, such as digestive tract disorders, liver damage, and myopathy. Therefore, finding alternative treatments for hypercholesterolemia is crucial.

[0003] Probiotics are live bacteria that benefit human health, with lactic acid bacteria being the primary probiotic in the human body. Studies have shown that lactic acid bacteria can reduce cholesterol levels through assimilation, bile salt hydrolase decoupling, and coprecipitation. While Lactobacillus plantarum is also a common probiotic, it's often used to regulate intestinal flora, enhance immunity, and promote digestion. However, there are no reports of Lactobacillus plantarum that can degrade cholesterol and exhibits excellent hydrophobic properties in the prior art. Summary of the Invention

[0004] The present invention provides a Lactobacillus plantarum strain, a bacterial agent, a method for degrading cholesterol and an application thereof. Lactobacillus plantarum strain MRS1026.1 can degrade cholesterol and has good surface hydrophobicity.

[0005] In order to solve the above technical problems, the following technical solutions are proposed:

[0006] The invention provides a Lactobacillus plantarum strain MRS1026.1, with a preservation number of CGMCC No.34166.

[0007] The present invention provides a bacterial agent, comprising the Lactobacillus plantarum MRS1026.1 described in the above technical solution.

[0008] Preferably, the bacterial agent includes one or more of the culture solution, bacterial suspension and supernatant of Lactobacillus plantarum MRS1026.1.

[0009] Preferably, the method for preparing the culture solution comprises: inoculating the Lactobacillus plantarum MRS1026.1 into a culture medium for culturing to obtain a culture solution.

[0010] The present invention provides the use of Lactobacillus plantarum MRS1026.1 described in the above technical solution or the bacterial agent described in the above technical solution in degrading cholesterol or preparing a product that degrades cholesterol.

[0011] Preferably, the cholesterol content in the product to be degraded is 90-100 μg / mL.

[0012] The present invention provides a method for degrading cholesterol, comprising the following steps: mixing the Lactobacillus plantarum MRS1026.1 described in the above technical solution or the bacterial agent described in the above technical solution with a substance to be degraded containing cholesterol for degradation.

[0013] Preferably, after the mixing, the degradable material contains Lactobacillus plantarum MRS1026.1, and the viable cell count of Lactobacillus plantarum MRS1026.1 is 1.0×10 6 CFU / mL.

[0014] Preferably, the degradation temperature is 30-38°C.

[0015] The degradation time is 20 to 50 hours.

[0016] The present invention provides the use of the Lactobacillus plantarum MRS1026.1 described in the above technical solution or the bacterial agent described in the above technical solution in the preparation of products with antioxidant properties.

[0017] The present invention has the beneficial effects of providing a Lactobacillus plantarum strain MRS1026.1, which has a preservation number of CGMCC No. 34166. The Lactobacillus plantarum strain MRS1026.1 is isolated from cheese. The strain MRS1026.1 has good bile salt tolerance and antioxidant properties. The surface hydrophobicity of the strain MRS1026.1 is good, indicating that after passing through the gastrointestinal tract, the strain also has strong intestinal epithelial cell adhesion ability, can inhibit the growth of pathogens, exert a prebiotic effect, and lower cholesterol. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a standard curve diagram used in the determination of cholesterol degradation rate;

[0019] Figure 2 is the MAGA evolutionary tree of strain MRS1026.1;

[0020] Figure 3 This is the standard curve used in antioxidant assay.

[0021] Biological Deposit Description

[0022] Lactobacillus plantarum MRS1026.1 was deposited in the General Microbiology Center of China Culture Collection Administration (CGMCC) on April 11, 2025. The deposit address is: No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, and the deposit number is CGMCC No. 34166. DETAILED DESCRIPTION

[0023] The present invention provides a strain of Lactobacillus plantarum MRS1026.1, with a deposit number of CGMCC No. 34166. The 16S rDNA gene sequence of the Lactobacillus plantarum MRS1026.1 of the present invention is shown in SEQ ID No. 1.

[0024] The present invention uses cheese as a raw material to isolate a Lactobacillus plantarum MRS1026.1. The colony of the strain MRS1026.1 is white, slightly yellow, and translucent, and is capable of degrading cholesterol. Within the range of 0.1% to 0.3% bile salt, the strain MRS1026.1 has good bile salt tolerance, high surface hydrophobicity, high self-aggregation ability, and certain antioxidant capacity.

[0025] The invention uses the 16S rDNA sequence of Lactobacillus plantarum MRS1026.1 to perform BLAST homologous sequence search in NCBI, constructs a phylogenetic tree with the obtained sequences with high homology, and determines that the strain MRS1026.1 is Lactobacillus plantarum.

[0026] The present invention provides a bacterial agent, comprising the Lactobacillus plantarum MRS1026.1 described in the above technical solution.

[0027] As an optional embodiment, the application form of the Lactobacillus plantarum MRS1026.1 of the present invention includes one or more of culture solution, bacterial suspension and supernatant.

[0028] As an optional embodiment, the method for preparing the bacterial suspension of the present invention comprises the following steps: inoculating the Lactobacillus plantarum MRS1026.1 into a culture medium for culturing to obtain a culture solution.

[0029] As another optional embodiment, the present invention inoculates the plant lactobacillus MRS1026.1 into a liquid MRS culture medium for resuscitation culture to obtain a seed liquid. As an optional embodiment, the present invention does not specifically limit the method of inoculation, and a conventional method can be used. As an optional embodiment, the temperature of the resuscitation culture of the present invention is 33°C to 39°C, or 35 to 37°C; in a specific embodiment of the present invention, the temperature of the resuscitation culture is 33, 34, 35, 36, 37, 38 or 39°C. The time of the resuscitation culture is 22 to 26 hours, or 23 to 25 hours. In a specific embodiment of the present invention, the time of the resuscitation culture is 22, 23, 24, 25 or 26 hours. The rotation speed of the resuscitation culture is 170 to 200 rpm, more preferably 180 rpm.

[0030] As another optional embodiment, the present invention inoculates the seed liquid into a liquid MRS culture medium for expansion culture to obtain an activated bacterial liquid, i.e., a culture solution. As an optional embodiment, the inoculation amount of the inoculation of the present invention is 1% to 3% of the volume of the culture medium, more preferably 2%. The present invention does not specifically limit the method of inoculation, and a conventional method can be used. As an optional embodiment, the temperature of the expansion culture is 33°C to 38°C, or 35 to 37°C; in a specific embodiment of the present invention, the temperature of the expansion culture is 33, 34, 35, 36, 37 or 38°C. The time of the expansion culture of the present invention is 22 to 26 hours, more preferably 24 hours. In a specific embodiment of the present invention, the time of the expansion culture is 22, 23, 24, 25 or 26 hours. The rotation speed of the expansion culture of the present invention is 170 to 190 rpm, and in a specific embodiment of the present invention, the rotation speed of the culture is 170, 180 or 190 rpm. As an optional embodiment, the composition of each 1L of the liquid MRS culture medium includes: 10g peptone, 5g beef powder, 4g yeast powder, 2g glucose, 1ml Tween 80, 2g dipotassium hydrogen phosphate, 5g sodium acetate, 2g triammonium citrate, 0.2g magnesium sulfate, 0.05g manganese sulfate and 1000ml distilled water.

[0031] The culture fluid is obtained, and the culture fluid is centrifuged to obtain bacterial cells, and the bacterial cells are washed and resuspended to obtain a bacterial suspension. The present invention does not specifically limit the parameters of the centrifugation, and conventional methods can be used. The solvent used for washing and resuspending in the present invention includes PBS buffer. The OD value of the bacterial suspension in the present invention is 600 The effective viable bacteria count of Lactobacillus plantarum MRS1026.1 in the bacterial suspension is ≥1.0×10 6 CFU / mL, more preferably 1.0×10 7 CFU / mL.

[0032] The present invention provides the use of the Lactobacillus plantarum MRS1026.1 or the bacterial agent described in the above technical solution in degrading cholesterol or preparing a cholesterol-degrading product. In the embodiments of the present invention, a product to be degraded with a cholesterol content of 90 to 100 μg / mL is used as an example for illustration.

[0033] As an optional embodiment, the type and preparation method of the product of the present invention are not particularly limited, and conventional methods can be used.

[0034] The present invention provides a method for degrading cholesterol, comprising the following steps: mixing the Lactobacillus plantarum MRS1026.1 described in the above technical solution or the bacterial agent described in the above technical solution with a substance to be degraded containing cholesterol for degradation.

[0035] As an optional embodiment, the present invention has no special limitation on the mixing method, and a conventional method can be used.

[0036] As an optional embodiment, the degradation temperature of the present invention is 30°C to 38°C, or 35°C to 37°C. In specific embodiments of the present invention, the expansion culture temperature is 33, 34, 35, 36, 37, or 38°C. The degradation time of the present invention is 20 to 50 hours, or 24 to 48 hours. As an optional embodiment, the cholesterol content of the product to be degraded is 90 to 100 μg / mL.

[0037] The present invention provides the use of the Lactobacillus plantarum MRS1026.1 described in the above technical solution or the bacterial agent described in the above technical solution in the preparation of products with antioxidant properties.

[0038] As an optional embodiment, the type and preparation method of the product of the present invention are not particularly limited, and conventional methods can be used.

[0039] In order to further illustrate the present invention, the technical solution provided by the present invention is described in detail below with reference to the accompanying drawings and embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0040] 1. Experimental materials and instruments

[0041] 10 mg / mL cholesterol micelle solution: Weigh 1 g of cholesterol, add anhydrous ethanol, and dilute to 100 mL.

[0042] 1.0 mg / mL cholesterol standard stock solution: Take 10 mL of 10 mg / mL cholesterol micellar solution, add anhydrous ethanol, and dilute to 100 mL.

[0043] 0.1 mg / mL cholesterol standard working solution: Take 10 mL of 1.0 mg / mL cholesterol standard stock solution, add anhydrous ethanol, and dilute to 100 mL.

[0044] MRS-CHOL medium: Add 10 g / L cholesterol micelle solution to MRS medium containing 0.2% (w / v) bile salts to make the final cholesterol concentration 100 μg / mL.

[0045] Ammonium ferric sulfate colorimetric solution: Weigh 4.43 g of ammonium ferric sulfate and dissolve it in 100 mL of 85% phosphoric acid to obtain the ammonium ferric sulfate stock solution. Add 8 mL of the ammonium ferric sulfate stock solution to 92 mL of concentrated sulfuric acid to obtain the ammonium ferric sulfate colorimetric solution.

[0046] Example 1

[0047] 1. Bacterial strain isolation

[0048] Use a sterile toothpick to scrape an appropriate amount of cheese, place it in 100 mL of sterile saline, and place it in a constant temperature shaker at 37°C, 180 rpm, and mix for 15 minutes. Dilute and spread the mixed sample on an MRS solid culture medium plate, and place the plate in a constant temperature incubator at 37°C for 24 hours. A total of 40 lactic acid bacteria strains were isolated. Use a sterile toothpick to pick a single colony of each lactic acid bacteria strain in 20 mL of MRS culture medium, and incubate it in a constant temperature shaker at 37°C, 180 rpm for 24 hours. The cultured bacterial solution and 50% glycerol are stored in a -80°C refrigerator at a volume ratio of 1:1.

[0049] 2. Bacteria activation

[0050] Remove the bacterial culture from step 1 from the -80°C freezer and dissolve at room temperature. Inoculate 1 mL of glycerol stock into 20 mL of MRS medium and incubate on a shaker at 37°C, 180 rpm for 24 hours to resuscitate the culture. Inoculate the revived bacterial solution into 20 mL of fresh MRS medium at a volume ratio of 3% by volume. Incubate on a shaker at 37°C, 180 rpm for 24 hours to activate the bacterial solution.

[0051] 3. In vitro screening of cholesterol-lowering lactic acid bacteria

[0052] 3.1 Drawing of cholesterol standard curve

[0053] Pipette 0.0mL, 0.5mL, 1.0mL, 1.5mL, 2.0mL of 0.1mg / mL cholesterol standard working solution into a test tube, add 4mL, 3.5mL, 3.0mL, 2.5mL, 2mL of anhydrous ethanol respectively, mix thoroughly, add 2mL of ammonium ferric sulfate colorimetric solution, mix well, react to room temperature, pipette 200μL of reaction solution into an enzyme-labeled 96-well plate, and measure the absorbance at 570nm. With cholesterol concentration as the horizontal axis, OD 570 Draw the standard curve with y as the vertical axis.

[0054] Cholesterol standard curve Figure 1 As shown in the figure, there is good linearity in the cholesterol concentration range of 0 to 0.05 μg / mL, R 2 =0.9991, cholesterol concentration and OD 560 The linear regression equation is: y = 4.5288x + 0.04704, where x represents the concentration of cholesterol and y represents the absorbance value.

[0055] 3.2 Determination of cholesterol degradation rate

[0056] The activated bacterial solution in step 2 was inoculated into MRS-CHOL medium at a volume ratio of 3%. The volume of MRS-CHOL medium was 20 mL, and then placed in a constant temperature incubator at 180 rpm and 37 ° C for 24 hours. The above reaction solution was placed in a high-speed centrifuge: 2400xg, 4 ° C centrifugation for 30 minutes, and the supernatant solution was diluted 5 times to obtain a reaction dilution solution. After the reaction dilution solution and ammonium ferric sulfate color development solution were reacted to room temperature at a volume ratio of 1:3, the absorbance was measured at 560 nm. Among them, the uninoculated MRS-CHOL medium was used as the control group, and the cholesterol degradation rate was as follows:

[0057] Cholesterol degradation rate (%) = [(AB) × 100] / A;

[0058] Wherein: A is the absorbance of the control group; B is the absorbance of the experimental group.

[0059] 40 strains of lactic acid bacteria were isolated and their cholesterol degradation rates were determined by ammonium ferric sulfate colorimetric method. The OD 570 The absorbance value of the control group was 0.9903, the absorbance values ​​of the three parallel experiments in the experimental group were 0.5626, 0.5465 and 0.5414, and the cholesterol degradation rate of strain MRS1026.1 was 44.45%.

[0060] 4. Bacterial species identification

[0061] The lactic acid bacteria with a high cholesterol degradation rate obtained in step 3.2 were activated and sent to Guangzhou Aiki Biotechnology Co., Ltd. for 16S rDNA identification. The 16S rDNA of strain MRS1026.1 is shown in SEQ ID NO. 1:

[0062]

[0063] The 16S rDNA sequencing results were uploaded to NCBI for 16S rDNA homology comparison, and the phylogenetic tree was constructed using MAGA software. The phylogenetic tree is as follows Figure 2 Among them, the 16S region of MRS1026.1 was compared with the NCBI database, and the similarity with Lactiplantibacillus plantarum was the highest, at 99.83%. Combined with the phylogenetic tree, strain MRS1026.1 was identified as Lactiplantibacillus plantarum.

[0064] Example 2

[0065] The activated bacterial solution obtained in step 2 of Example 1 was treated by high-speed centrifugation at 10,000 × g to obtain bacterial sediment, and the bacterial cells were washed twice with PBS buffer solution and resuspended to obtain a bacterial suspension. The OD value of the bacterial suspension was 0.05. 600 Adjusted to 1.0;

[0066] The activated bacterial solution obtained in step 2 of Example 1 was treated by high-speed centrifugation at 10,000 × g to obtain bacterial sediment, and the bacterial cells were washed twice with PBS buffer solution and resuspended to obtain a bacterial suspension. The OD value of the bacterial suspension was 0.05. 600 Adjusted to 0.6.

[0067] The following measurements were performed:

[0068] 1. Acid resistance

[0069] The bacterial suspension (OD 600 =1.0) was inoculated into MRS medium with a pH value of 3.0, cultured at 37°C and 180 rpm for 4 h, and the OD 600 Then, the OD 600 =1.0 bacterial suspension was inoculated into MRS medium with a pH value of 6.0 as blank control.

[0070] Acid resistance (%) = A1 / A0 × 100;

[0071] A1 is the absorbance of the experimental group, and A0 is the absorbance of the control group.

[0072] Under normal circumstances, the body's post-meal food emptying period is 1 to 2 hours, and the gastric pH ranges from 3.0 to 6.0. For Lactobacillus plantarum to function effectively without any protective conditions, it must have a certain tolerance to low pH environments to ensure it can enter the intestines without becoming inactivated. Therefore, when Lactobacillus plantarum was placed at a pH of 3.0 and its acid resistance was evaluated, strain MRS1026.1 showed an acid resistance of 37.52%.

[0073] 2 Bile salt tolerance

[0074] The bacterial suspension (OD 600 =1.0) were inoculated into MRS medium containing 0.0%, 0.1%, 0.2%, and 0.3% bile salts, and cultured in a constant temperature shaker at 37°C and 180 rpm for 4 h. The OD values ​​were then measured. 600 .

[0075] Bile salt tolerance (%) = At / A0 × 100;

[0076] Where At is the absorbance of the bacterial solution obtained from the culture medium at different bile salt concentrations; A0 is the absorbance of the bacterial solution obtained from the culture medium without bile salts.

[0077] Food passes through the peristalsis of the stomach and further enters the duodenum. The complete emptying of food will be completed within 4 to 6 hours. Food enters the small intestine from the stomach for digestion and absorption. The small intestine is an important part of the digestion and absorption of the entire human body. It is also an important place for Lactobacillus plantarum to play a probiotic role. However, the small intestine contains 0.03% to 0.3% bile salts. Higher bile salt concentrations will have a greater hydrophobic effect, destroying the cell membrane of Lactobacillus plantarum. The number of live bacteria of Lactobacillus plantarum is reduced, and it is difficult to play a probiotic role. Appropriate bile salt hydrolase activity can effectively help Lactobacillus plantarum to fight bacteria and lower cholesterol. Therefore, Lactobacillus plantarum must also have a higher bile salt tolerance. 0-0.3% bile salts are used to simulate the bile salt environment in the human small intestine. The strain MRS1026.1 has good bile salt tolerance. In the range of 0.1%, 0.2% and 0.3% bile salts, OD 600 The OD values ​​of blank control (0.0% bile salt) were 0.9239, 0.9220, and 0.9092, respectively. 600 was 1.054, and the bile salt tolerance was 87.61%, 87.43% and 86.23% respectively. The bile salt tolerance curve changed smoothly with the increase of bile salt concentration.

[0078] 3. Surface hydrophobicity

[0079] A1 treatment: Take 3 mL of bacterial suspension (OD 600 =0.6), add 1 mL of chloroform, vortex for 2 min to mix thoroughly, place at room temperature for 1 h, carefully aspirate the aqueous phase and measure OD600 .

[0080] A0 treatment: take 4 mL of bacterial suspension (OD 600 =0.6), vortex for 2 min to mix thoroughly, place at room temperature for 1 h, and carefully aspirate the aqueous phase to measure OD 600 .

[0081] Surface hydrophobicity (%) = (A0-A1) / A0×100;

[0082] Among them, A0 is the OD measured without adding chloroform 600 ; A1 is the OD measured by adding chloroform 600 .

[0083] Surface hydrophobicity is a physical and chemical property of cells, which will affect the ability of bacteria to self-aggregate and adhere in the intestine. The adhesion of probiotics to intestinal epithelial cells is one of the important conditions for probiotics to play a probiotic role. Probiotic adhesion can prevent probiotics from falling off due to intestinal peristalsis, thus failing to play a probiotic role. At the same time, probiotics adhere to intestinal epithelial cells to better compete with other intestinal bacteria, which is more conducive to the play of probiotic effects. The surface hydrophobicity of cells is related to the glycol substances and proteins on the cell surface, and the hydrophilicity of the cell surface is related to the polysaccharides on the cell surface. The surface hydrophobicity and self-aggregation ability of bacteria are directly related to the adhesion ability of bacteria. Therefore, Lactobacillus plantarum must also have good hydrophobicity and self-aggregation ability. A1 three parallel experiments OD 600 The OD values ​​of three parallel experiments were 0.1476, 0.1470, and 0.1538, respectively. 600 are 0.5270, 0.5648, and 0.5615, and strain MRS1026.1 has a higher surface hydrophobicity of 72.85%.

[0084] 4. Self-aggregation (self-aggregation ability)

[0085] Take 4 mL of bacterial suspension (OD 600 =1.0) and incubated at 37°C. After incubation for 0, 2, 3, 4, 6, 8, 12, and 24 h, the supernatant was carefully aspirated to measure OD 600 .

[0086] Probiotics need to adhere to the human intestinal epithelial cells to exert their probiotic effects. The self-aggregation ability of a strain refers to the ability of the same strain to aggregate into a group, which helps to form a biofilm and adhere to the host intestine while effectively avoiding the adhesion and invasion of pathogens. Therefore, the self-aggregation ability of probiotics is also of great significance. The self-aggregation rate of Lactobacillus plantarum increases with time and eventually tends to be stable. The OD values ​​of the incubation supernatant obtained after incubation for 0, 2, 3, 4, 6, 8, 12, and 24 hours are as follows: 600They were 1.075, 0.0667, 0.0638, 0.0657, 0.0649, 0.0657, 0.069 and 0.0581 respectively. During incubation for 0 to 2 hours, the self-aggregation ability curve of MRS1026.1 decreased rapidly, indicating a higher self-aggregation ability. After incubation for 8 hours, the self-aggregation ability curve of MRS1026.1 was basically stable.

[0087] 5. Antioxidant

[0088] The antioxidant activity was determined using the Biyuntian Total Antioxidant Capacity Detection Kit (FRAR method), kit number: S0116.

[0089] 5.1 Preparation of standard curve

[0090] The antioxidant curve is as follows Figure 3 , with good linearity, R 2 =0.9991, the linear regression equation is y=0.2497x+0.2113, where x represents the concentration of ferrous sulfate solution and y represents the absorbance value.

[0091] 5.2 Antioxidant activity of supernatant

[0092] The activated bacterial solution obtained in step 2 of Example 1 was centrifuged at 10000 x g to obtain the supernatant for FRAP assay to determine the antioxidant activity. Three parallel experiments were set up for the assay, and the supernatant was diluted 8 times the OD 593 They are 0.4557, 0.4584 and 0.4618 respectively.

[0093] 5.3 Cellular antioxidant capacity

[0094] The activated bacterial solution obtained in step 2 of Example 1 was centrifuged at 10000×g, and the bacterial precipitate was washed 2-3 times with an equal amount of PBS buffer solution to obtain cell solution. The antioxidant activity of the cell solution was determined by FRAP method. The cell solution was diluted 8 times to OD 593 They are 0.0831, 0.0814 and 0.0884 respectively.

[0095] 5.4 Antioxidant activity of intracellular products

[0096] The activated bacterial solution obtained in step 2 of Example 1 was centrifuged at 10000×g, and the bacterial precipitate was washed 2-3 times with an equal amount of PBS buffer solution, and ultrasonically disrupted to obtain a disrupted solution. The antioxidant activity of the disrupted solution, i.e., the antioxidant activity of the intracellular product, was determined by FRAP. The disrupted solution was diluted 8 times to OD 593 They are 0.0918, 0.0914 and 0.0954 respectively.

[0097] The antioxidant capacity of the supernatant of MRS1026.1 was 7.90 mM FeSO4, while the antioxidant capacity of the lysate and cell sap was poor. The antioxidant capacity of the supernatant of Lactobacillus plantarum was significantly greater than that of the cell sap and cell lysate. During the fermentation process, Lactobacillus plantarum produces antioxidant metabolites such as lactic acid, acetic acid, pyruvic acid, catalase, and superoxide dismutase.

[0098] 5.5 Gastrointestinal fluid tolerance

[0099] The activated bacterial solution obtained in step 2 of Example 1 was centrifuged at 10000×g to obtain bacterial pellets. The bacterial pellets were washed twice with PBS buffer solution, and the bacterial pellets were resuspended and the OD was adjusted. 600 To 1.0, a bacterial suspension was obtained. 1 mL of bacterial suspension was added to 9 mL of simulated gastric fluid and incubated in a constant temperature shaker at 37°C, 180 rpm for 2 h. The resulting culture was centrifuged at 10,000 x g. The bacterial pellet was washed with an equal volume of PBS, diluted and spread on a plate, and incubated in a constant temperature incubator at 37°C for 24 h. Plate counts were then performed.

[0100] The activated bacterial solution obtained in step 2 of Example 1 was centrifuged at 10,000 × g to obtain a bacterial pellet. 10 mL of simulated intestinal fluid was added to the bacterial pellet, and the pellet was cultured in a constant temperature shaker at 37°C and 180 rpm for 4 h. The pellet was then centrifuged at 10,000 × g, and the pellet was washed with an equal volume of PBS, diluted and spread, and cultured in a constant temperature incubator at 37°C for 24 h. The plate count was performed.

[0101] Generally speaking, food stays in the gastrointestinal tract for 4 to 6 hours, including 1 to 2 hours in the stomach and 4 to 5 hours in the intestines. Before probiotics reach the small intestine, the highly acidic conditions of gastric juice can destroy the proteins and lipids in the probiotic cell membrane. In addition, various digestive enzymes in the gastrointestinal tract can also damage the cell structure of probiotics, resulting in inhibition or even inactivation of probiotic cell activity. Therefore, in vitro digestion simulation experiments were conducted on Lactobacillus plantarum. After 2 hours of in vitro gastric juice simulation and 4 hours of in vitro intestinal fluid simulation, the survival rate of Lactobacillus plantarum was measured. The survival rate of Lactobacillus plantarum in the digestive tract simulation is shown in Table 1.

[0102] Table 1 Survival rate of strain MRS1026.1 under gastric fluid simulation and intestinal fluid simulation

[0103]

[0104] In summary, the plant lactobacillus (Lactiplantibacillus plantarum) MRS1026.1 of the present invention has good bile salt tolerance, antioxidant properties, and good surface hydrophobicity of the strain MRS1026.1, indicating that after passing through the gastrointestinal tract, the strain must also have strong intestinal epithelial cell adhesion ability, can inhibit the growth of pathogens, exert a prebiotic effect, and reduce cholesterol content.

[0105] Although the above embodiment provides a detailed description of the present invention, it is only a part of the embodiments of the present invention, not all of the embodiments. People can also obtain other embodiments based on this embodiment without creativity, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. A strain of Lactobacillus plantarum MRS1026.1, deposited with CGMCC No. 34166.

2. A bacterial agent, characterized in that The invention comprises the Lactobacillus plantarum MRS1026.1 according to claim 1.

3. The bacterial agent according to claim 2, characterized in that The bacterial agent comprises one or more of the culture solution, bacterial suspension and supernatant of Lactobacillus plantarum MRS1026.

1.

4. The bacterial agent according to claim 3, characterized in that The method for preparing the culture solution comprises: inoculating the Lactobacillus plantarum MRS1026.1 into a culture medium for culturing to obtain the culture solution.

5. Use of the Lactobacillus plantarum MRS1026.1 according to claim 1 or the bacterial agent according to any one of claims 2 to 4 in degrading cholesterol or preparing a product that degrades cholesterol.

6. The use according to claim 5, characterized in that The cholesterol content in the product to be degraded is 90-100 μg / mL.

7. A method for degrading cholesterol, characterized in that: The method comprises the following steps: mixing the Lactobacillus plantarum MRS1026.1 according to claim 1 or the bacterial agent according to any one of claims 2 to 4 with a substance to be degraded containing cholesterol for degradation.

8. The method according to claim 7, characterized in that: After the mixing, the degradable material contains Lactobacillus plantarum MRS1026.1, and the number of viable bacteria of Lactobacillus plantarum MRS1026.1 is 1.0×10 6 CFU / mL.

9. The method according to claim 7, characterized in that: The degradation temperature is 30-38° C., and the degradation time is 20-50 hours.

10. Use of the Lactobacillus plantarum MRS1026.1 according to claim 1 or the bacterial agent according to any one of claims 2 to 4 in the preparation of a product having antioxidant properties.

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