Pediococcus acidilactici with acid resistance, bile salt resistance and antibacterial activity and its application

Abstract

The present invention belongs to the technical field of probiotics, and particularly relates to a Pediococcus acidilactici with acid resistance, bile salt resistance and antibacterial activity and its application. The Pediococcus acidilactici TR19 of the present invention has a preservation number of CGMCC NO. 31330, and the microbial taxonomic name is Pediococcus acidilactici Pediococcus acidilactici , this strain has good acid resistance and bile salt resistance characteristics, and at the same time has strong antibacterial effects on Escherichia coli, Bacillus cereus, Staphylococcus aureus and Salmonella typhimurium. In addition, this strain has good degradation ability for both nitrite and cholesterol, and has strong applicability.

Description

Technical Field

[0001] The present invention belongs to the technical field of probiotics, and particularly relates to a Pediococcus acidilactici with acid resistance, bile salt resistance and antibacterial activity and its application. Background Art

[0002] In recent years, food poisoning and intestinal diseases caused by pathogenic microorganisms have occurred from time to time. Bacterial food poisoning has become an important factor affecting food safety, which will then cause the imbalance of the human intestinal flora and have an adverse impact on human health. The most common method for preventing and treating bacterial diseases is to use antibiotics. However, long-term and excessive use of antibiotics will lead to the emergence of bacterial drug resistance. According to research, almost all bacteria can now obtain various different drug resistance genes, and each antibiotic can be resisted by bacteria to varying degrees. Therefore, it is particularly important to study alternatives to antibiotics, and lactic acid bacteria have been reported in a large number of literatures to have great potential in inhibiting the growth of pathogenic microorganisms.

[0003] Lactic Acid Bacteria (LAB) are the dominant flora in traditional fermented foods, specifically referring to a group of Gram-positive, sporeless bacteria that grow anaerobically or facultatively anaerobically and can ferment carbohydrates to produce a large amount of lactic acid. Lactic acid bacteria are widely distributed in animals, plants, the human body and the environment. Currently known lactic acid bacteria include Lactobacillus, Lactococcus, Streptococcus, Leuconostoc, Pediococcus, Streptococcus, Enterococcus, Bifidobacterium, etc. However, there are still a large number of lactic acid bacteria resources that have not been developed and utilized. Except for a small number of lactic acid bacteria, the vast majority of lactic acid bacteria have good safety and probiotic effects and are generally recognized as safe (GRAS) microorganisms in the food field. Lactic acid bacteria have the probiotic effects of maintaining the balance of the human intestinal flora, relieving inflammation and regulating the body's immunity. Moreover, the metabolites produced during their fermentation process, such as acidic and polypeptide substances, not only give food a unique flavor, but also can inhibit the growth of pathogenic microorganisms and spoilage bacteria. As a member of probiotics and the normal intestinal flora, lactic acid bacteria must overcome the adverse environments of the oral cavity, stomach (high acidity, pepsin) and the upper digestive tract (bile salts, pancreatic enzymes) during the transmission process from the oral cavity to the intestine after ingestion in order to exert beneficial effects on the host in the form of live bacteria. Therefore, the ability to resist the human gastrointestinal environment has become an important property and index for evaluating probiotics, and in vitro effectiveness screening can to a certain extent reflect the actual survival ability of lactic acid bacteria in the real gastrointestinal environment.

[0004] Therefore, it is of great social significance and economic value to further screen out lactic acid bacteria that can survive in the gastrointestinal tract environment and have good antibacterial effects on common pathogenic microorganisms, so as to maintain the dynamic balance of the intestinal flora.

[0005] Nitrite is mainly used as a food additive (for coloring and preservation) in the processing and production of food, and the nitrite in fermented foods mainly comes from the reduction of nitrate by some microorganisms during the food fermentation process. Nitrite will be converted into harmful substances such as amines in the stomach, such as nitrosamines with strong carcinogenic effects. In addition, nitrite will also cause red blood cells to lose their oxygen-carrying capacity, thus causing methemoglobinemia. Existing studies have shown that lactic acid bacteria have a strong degradation effect on nitrite in food, mainly through the enzymatic metabolites produced (producing nitrite reductase), other metabolites (carbohydrates, amino acids, lipids, nucleotides, and nitrogen metabolism, etc.), and lactic acid (reacting with H+ and nitrite) to degrade nitrite. Therefore, lactic acid bacteria have great application potential in controlling the nitrite content in fermented foods.

[0006] For example, CN117210350A discloses a Pediococcus acidilactici and its application, which relates to the field of extraction, identification, and application of microorganisms. This Pediococcus acidilactici is derived from earthworms and is named: Pediococcus acidilactici strain 11029, which was deposited at the General Microbiological Center of the China Committee for Culture Collection of Microorganisms on December 16, 2021, with the deposit number: CGMCC: 24122. The Pediococcus acidilactici strain 11029 in this application has advantages such as good antibacterial effect, good acid and bile salt tolerance, rapid growth, and high biomass, but its tolerance and stress resistance are insufficient.

[0007] For example, CN108504601B discloses a newly isolated Pediococcus acidilactici HEW-AP27, which is deposited at the General Microbiological Center of the China Committee for Culture Collection of Microorganisms (abbreviated as CGMCC, address: Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, Postcode: 100101), with the deposit number CGMCC NO.15419 and the deposit date of March 7, 2018. This application also provides a preparation method for the live bacteria preparation of Pediococcus acidilactici, which specifically includes: using Pediococcus acidilactici as the fermentation strain, adopting an optimized fermentation process and fermentation medium, discharging the tank after first-stage, second-stage, and third-stage cultivation, centrifuging to obtain active bacterial sludge, adding a stabilizing and protecting agent, then granulating through a granulator, and then adding a coating solution in a coating machine for coating to finally obtain the live bacteria preparation of Pediococcus acidilactici. The Pediococcus acidilactici HEW-AP27 of this invention is acid-resistant, bile-salt-resistant, heat-resistant, has strong acid-producing performance, and can also inhibit the growth and reproduction of pathogenic bacteria. However, its degradation performance on nitrite and cholesterol has not been confirmed.

[0008] In view of this, the present invention is hereby provided. Summary of the Invention

[0009] The object of the present invention is to provide a Pediococcus acidilactici with acid resistance, bile salt resistance and antibacterial activity and its application. The Pediococcus acidilactici obtained by the present invention has good degradation performance on nitrite and cholesterol, and has strong tolerance and stress resistance.

[0010] In order to achieve the above object, the present invention provides the following technical solutions:

[0011] In the first aspect, an embodiment of the present invention provides a Pediococcus acidilactici with acid resistance, bile salt resistance and antibacterial activity. The Pediococcus acidilactici was deposited at the General Microbiological Center of the China Committee for Culture Collection of Microorganisms on July 17, 2024, with the deposit number CGMCC NO. 31330, and its microbial classification name is Pediococcus acidilactici Pediococcus acidilactici .

[0012] In a preferred embodiment, the Pediococcus acidilactici is named TR19.

[0013] In the second aspect, an embodiment of the present invention provides a culture method for a Pediococcus acidilactici with acid resistance, bile salt resistance and antibacterial activity, including the following steps:

[0014] Mix sweet fermented grains and sterile physiological saline, homogenize, dilute and then culture on a plate, and obtain the strain after separation and purification.

[0015] In a preferred embodiment, the homogenization is carried out in a sterile homogenization bag.

[0016] In a preferred embodiment, the dosage ratio of the sweet fermented grains to the sterile physiological saline is 25 g:(200 - 300) ml.

[0017] In a preferred embodiment, the homogenization includes:

[0018] Use a percussion homogenizer to percuss at 400 - 500 r / min for 2 - 4 min.

[0019] In a preferred embodiment, the dilution includes diluting 10 times with physiological saline.

[0020] In a preferred embodiment, it is cultured using MRS agar medium.

[0021] In a preferred embodiment, the culture conditions are: temperature 30 - 40 °C, time 36 - 72 h.

[0022] In a preferred embodiment, the viable cell count in the bacterial liquid obtained after culture is 108 ~10 9 CFU / mL.

[0023] In a third aspect, an embodiment of the present invention provides an application of the above-mentioned Pediococcus acidilactici with acid resistance, bile salt resistance and antibacterial activity in degrading nitrite.

[0024] In a fourth aspect, an embodiment of the present invention provides an application of the above-mentioned Pediococcus acidilactici with acid resistance, bile salt resistance and antibacterial activity in degrading cholesterol.

[0025] In a fifth aspect, an embodiment of the present invention provides an application of the above-mentioned Pediococcus acidilactici with acid resistance, bile salt resistance and antibacterial activity in the preparation of drugs for degrading nitrite.

[0026] In a sixth aspect, an embodiment of the present invention provides an application of the above-mentioned Pediococcus acidilactici with acid resistance, bile salt resistance and antibacterial activity in the preparation of drugs for degrading cholesterol.

[0027] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows:

[0028] 1. The Pediococcus acidilactici strain TR19 provided by the present invention has strong acid resistance, bile salt resistance, and tolerance to artificial gastrointestinal fluid, and has the potential to survive and colonize in the human digestive tract environment.

[0029] 2. The Pediococcus acidilactici strain TR19 provided by the present invention has strong antibacterial activity against 4 pathogenic microorganisms, and has great potential in maintaining the dynamic balance of intestinal flora and product preservation and anti-corrosion.

[0030] 3. The Pediococcus acidilactici strain TR19 provided by the present invention has strong degradation performance for nitrite and cholesterol. Description of the Drawings

[0031] The Pediococcus acidilactici TR19 of the present invention was deposited at the General Microbiology Center of the China Committee for Culture Collection of Microorganisms on July 17, 2024, with the deposit number CGMCC NO. 31330, and its microbial classification name is Pediococcus acidilactici Pediococcus acidilactici .

[0032] Figure 1 It is a microbiological morphological observation diagram of the inventive strain TR19, where a is the colony morphological characteristics of the strain after culturing on an MRS plate for 48 h, and b is the cell morphology observed under a 100-fold optical microscope after Gram staining of the strain.

[0033] Figure 2Observation of the antibacterial circle morphology of the inventive strain TR19 against 4 indicator bacteria. Among them, a is the size of the antibacterial circle of strain TR19 against Escherichia coli, b is the size of the antibacterial circle of strain TR19 against Bacillus cereus, c is the size of the antibacterial circle of strain TR19 against Salmonella typhimurium, and d is the size of the antibacterial circle of strain TR19 against Staphylococcus aureus.

[0034] Figure 3 Application diagram of the inventive strain TR19 in nitrite degradation. Specifically, it is the standard curve for nitrite determination (with the absorbance value at OD538nm as the ordinate and the nitrite content (μg) as the abscissa).

[0035] Figure 4 Application diagram of the inventive strain TR19 in nitrite degradation. Specifically, it is the degradation rate of nitrite by strain TR19 at different time periods.

[0036] Figure 5 Standard curve with the absorbance value at OD560nm as the ordinate and the cholesterol content (μg / mL) as the abscissa, which can be used as a quantitative index for detecting the cholesterol content in samples. Detailed implementation mode

[0037] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0038] Unless otherwise specified, all raw materials used in the present invention are obtained commercially.

[0039] Example 1

[0040] Isolation, screening, identification and preservation of Pediococcus acidilactici TR19

[0041] Randomly purchase sweet fermented wheat samples from Dingxi City, Gansu Province. Weigh 25 g of the sample aseptically into a sterile homogenization bag, add 225 mL of sterile physiological saline, and use a beating homogenizer to beat for 2 min at 420 r / min to prepare a 1:10 sample homogenate. Take 1 mL of the sample homogenate and perform 10-fold serial dilutions with sterile physiological saline. Select 10 ~1 ~10 ~60.1 mL of each dilution was spread on MRS plates and anaerobically cultured at 36°C for 72 h. After that, the colony characteristics were carefully observed, and lactic acid bacteria with different morphologies were isolated and purified. The plate streaking method was used to pick single colonies with good growth status and different morphologies on MRS plates for repeated isolation and purification. The morphological characteristics of the purified colonies, such as shape, color, smoothness, and edge, were observed and recorded. At the same time, the lactic acid bacteria were Gram-stained and examined under a microscope. The morphology of the bacterial cells was observed under an optical microscope (100× objective lens). Strains with positive Gram staining were initially identified as suspected lactic acid strains, and physiological and biochemical tests and 16S rDNA identification were carried out.

[0042] As Figure 1 shown in a of Figure 1 , the colony morphological characteristics were: round, milky white, neat edge, low elevation, moist surface, smooth, opaque. As

[0043] Table 1 Physiological and Biochemical Characteristics of Pediococcus acidilactici TR19

[0044] Catalase activity - Sorbitol - Lactose - Urease activity - Fructose + Ribose + Amino acid decarboxylase activity - Glucose + Rhamnose - Gelatinase activity - Galactose + Sucrose - Indole test - Mannitol - Xylose + Nitrate reduction characteristics - Maltose -

[0045] Note: "+" indicates a positive reaction; "-" indicates a negative reaction

[0046] Results of Molecular Biology Identification:

[0047] The 16S rDNA sequences of lactic acid bacteria were amplified and sequenced. The universal primers for lactic acid bacteria were 1492R (5’-GGTTACCTTGTTACGACTT-3’) and 27F (5’-AGAGTTTGATCMTGGCTCAG-3’). The PCR amplification reaction conditions were: 94°C for 5 min; 94°C for 1 min, 60°C for 1 min, 72°C for 1 min, 35 cycles, and 72°C for 10 min. After the amplified products were detected by gel electrophoresis, they were sent to Sangon Biotech (Shanghai) Co., Ltd. for sequence determination. The 16S rDNA gene sequence determination results of strain TR19 were as follows:

[0048]

[0049] The detection sequence was analyzed for homology alignment with the sequences in GenBank (http: / / www.ncbi.nlm.nih.gov) using the NCBI Blast software. It was found that the homology between strain TR19 and Pediococcus acidilactici (ON631864.1) was 99.93%. According to the principle that homology > 97% indicates the same species, combined with the morphological characteristics, physiological and biochemical characteristics of the strain. The final identification result of this strain was Pediococcus acidilactici ( Pediococcus acidilactici ), named Pediococcus acidilactici TR19 ( Pediococcus acidilactici TR19), which was deposited in the General Microbiology Center of the China Committee for Culture Collection of Microorganisms on July 17, 2024, with the deposit number CGMCC NO.31330.

[0050] Example 2

[0051] Acid and bile salt tolerance experiments of Pediococcus acidilactici TR19

[0052] (1) Determination of acid tolerance

[0053] After the strain TR19 was activated and cultured, 10 mL of the culture solution was centrifuged at 5000 g for 15 min at 4°C to collect the bacterial cells. 2 mL of fresh MRS culture solution was added to the bacterial cells, and after mixing, a bacterial suspension was prepared. The bacterial suspension was inoculated into MRS liquid media with pH values of 1.5, 2.5, and 3.5 (adjusted with hydrochloric acid) at an inoculation amount of 1% - 2%, so that the viable cell count was controlled within the range of 10 8 ~10 9 CFU / mL. The MRS (pH 6.4) liquid medium without pH adjustment was used as a control. After the culture solution was cultured at 36°C for 3 h, the viable cell count was calculated by the MRS plate counting method, and the measurement was performed in parallel 3 times. The survival rate = (N1 / N2) × 100%, where N1 was the viable cell count (CFU / mL) after 3 h of culture in the low-pH MRS liquid medium; N2 was the initial viable cell count (CFU / mL) measured on the MRS control medium. The viable cell count and survival rate of strain TR19 under different pH conditions are shown in Table 2 below. The experimental results showed that strain TR19 was not tolerant under the condition of pH 1.5 and no colonies grew. When the pH value was 2.5, the survival rate of strain TR19 was 35.23%. When the pH condition was 3.5, the survival rate of strain TR19 increased to 79.22%. The pH of gastric juice fluctuates greatly before and after eating. Generally, the pH is 1.5 on an empty stomach, and with the intake of food, the pH of the stomach rises to 3.0 or higher. Strain TR19 maintained a relatively high survival rate under the conditions of pH 2.5 and pH 3.5, and the viable cell count could reach 10 8CFU / mL, indicating that strain TR19 has strong acid tolerance.

[0054] Table 2 Acid tolerance test of Pediococcus acidilactici TR19

[0055]

[0056] (2)Determination of bile salt tolerance

[0057] Add 1% activated TR19 bacterial suspension to MRS medium containing 0.00% (blank), 0.10%, 0.20% and 0.30% bile salts (w / v), culture at 36 °C, sample after 4 h, perform viable cell counting by spread plate method, calculate the survival rate, and measure in parallel 3 times. The survival rate = (A / B) × 100%, where A is the number of viable cells (CFU / mL) in MRS culture solution with different bile salt concentrations after 4 h, and B is the initial number of viable cells (CFU / mL) measured in the MRS control medium. The number of viable cells and survival rate of strain TR19 at different bile salt concentrations are shown in Table 3 below. The experimental results show that the survival rate of strain TR19 is negatively correlated with the bile salt concentration. The higher the bile salt concentration, the lower the survival rate. The survival rates of strain TR19 at bile salt concentrations of 0.1%, 0.2% and 0.3% are 61.31%, 18.97% and 16.44% respectively. The bile salt concentration in the intestine is in dynamic change, generally between 0.03% and 0.3%. Strain TR19 has a certain survival rate at a bile salt concentration of 0.3%, and the number of viable cells still remains at about 10 8 CFU / mL, indicating that this strain also has good bile salt tolerance.

[0058] Table 3 Bile salt tolerance test of Pediococcus acidilactici TR19

[0059]

[0060] (3) Determination of the ability to resist artificial gastrointestinal fluids: The activated TR19 bacterial suspension was inoculated at an inoculation amount of 1% into 3 mL of artificial gastric juice (in the system of NaCl (125 mmol / L), NaHCO3 (45 mmol / L), KCl (7 mmol / L), pepsin was added to make its concentration reach 3 g / L, and the pH was adjusted to 2.5), and cultured at 36 °C for 3 h, and the viable bacteria count was measured. After centrifuging the bacterial liquid cultured for 3 h, the bacteria were resuspended with an equal volume of artificial intestinal juice (0.1% trypsin and 0.3% bile salts were added to the above buffer system, and the pH was adjusted to 8.0), and continued to be cultured at 36 °C for 4 h, and the viable bacteria count after 4 h was measured. The ability of the strain to tolerate simulated gastrointestinal fluids was analyzed by the survival rate. The survival rate = (W / W0) × 100%, where W is the viable bacteria count (CFU / mL) of the strain cultured in the artificial gastrointestinal fluid environment for 7 h, and W0 is the initial viable bacteria count (CFU / mL). The viable bacteria count and survival rate of strain TR19 in the simulated artificial gastrointestinal fluid system are shown in Table 4 below. The experimental results show that the survival rate of strain TR19 after being treated in simulated gastric juice for 3 h is 74.82%. The viable bacteria count decreased slightly after being further treated in intestinal juice for 4 h, which is 8.92 Log CFU / mL. The survival rate after being cultured in the whole simulated gastrointestinal fluid system for 7 h is 60.30%, indicating that strain TR19 has good tolerance to pepsin and trypsin. The determination of simulated human gastrointestinal tract (GIT) movement is a set of standardized test systems, aiming to evaluate the survival rate of strains under simulated "normal" human stomach and small intestine conditions. At present, there is no unified standard for GIT screening at home and abroad. However, experimental data at home and abroad have shown that the critical value of the viable bacteria count for probiotic products to exert functional characteristics is 10 6 CFU / mL. After strain TR19 of the present invention was cultured in the simulated human gastrointestinal tract system for 7 h, the viable bacteria count reached the critical value requirement for probiotics to exert their effects, indicating that strain TR19 has good stress resistance to the gastrointestinal tract.

[0061] Table 4 Artificial gastrointestinal fluid tolerance test of Pediococcus acidilactici TR19

[0062]

[0063] Example 3

[0064] Antibacterial activity of Pediococcus acidilactici TR19

[0065] For the common pathogenic bacteria that cause food spoilage and foodborne diseases, 4 common pathogenic microorganisms were selected as indicator bacteria, including 2 strains of intestinal bacteria Escherichia coli and Salmonella typhimurium, belonging to Gram-negative bacteria, and 2 strains of Gram-positive bacteria Staphylococcus aureus and Bacillus cereus. The antibacterial activity of the fermentation supernatant of strain TR19 was determined by the Oxford cup method: Pour 20 mL of nutrient agar into a petri dish with a diameter of 9 cm, and respectively pipette 0.1 mL of the indicator bacteria suspension (OD 600nm = 0.1) into the nutrient plate, spread evenly, and dry in a laminar flow hood for 5 min. Place Oxford cups equidistantly on the plate, add 200 μL of the lactic acid bacteria culture supernatant, use the MRS medium without added bacterial solution as a control, place it in a constant temperature incubator at 36 °C for 12 h to 24 h, observe the size of the antibacterial zone, and measure the diameter of the antibacterial zone (mm). Compare and analyze the antibacterial activity of lactic acid bacteria strains against common intestinal pathogenic bacteria by the size of the antibacterial zone. The results are shown in Table 5 and Figure 2 as shown, Figure 2 In a-d in

[0066] Table 5 shows the antibacterial activity of Pediococcus acidilactici TR19.

[0067]

[0068] Example 4

[0069] The ability of Pediococcus acidilactici TR19 to degrade nitrite

[0070] After the strain was activated and cultured, it was inoculated into the MRS liquid medium with a NaNO2 content of 125 mg / L at an inoculation amount of 2%, and cultured statically in the dark at 36 °C. Fermentation broth was taken at 0 h, 6 h, 12 h, 24 h, 36 h, and 48 h respectively, and at 4 °C, 8000 g, Centrifuge for 5 min, take the supernatant, and refer to the method of N-(1-Naphthyl)ethylenediamine dihydrochloride method in GB 5009.33~2016 "National Food Safety Standard Determination of Nitrite and Nitrate in Foods" to determine the nitrite content in the fermentation broth (the main reagents used in the experiment are shown in Appendix 1). Measure the absorbance at a wavelength of 538 nm, and measure in parallel 3 times for each time period. According to the nitrite degradation rate, evaluate the ability of lactic acid bacteria to degrade nitrite. The nitrite degradation rate % = (B0 - B) × 100 / B0, where B0 represents the initial content of NaNO2 in the MRS culture medium without inoculated strains (mg / kg), and B represents the content of NaNO2 in the fermentation supernatant at different times after inoculating the strains (mg / kg).

[0071] The results are shown in Figure 3 and Figure 4 As shown, the results of the nitrite degradation experiment show that strain TR19 has a very good degradation effect on sodium nitrite. After being treated in the medium containing sodium nitrite for 36 h, the degradation rate reached more than 99%, and almost all of the sodium nitrite was degraded. Compared with the existing research reports at home and abroad, the rate of strain TR19 degrading nitrite is relatively fast. After culturing for 6 h, the nitrite degradation rate is about 30%, and the degradation rate reaches 80% after 12 h. Nitrite is an important factor causing the safety of fermented foods. When vegetables and crops are planted, due to the application of a large amount of nitrogen fertilizer, their roots contain a large amount of nitrate. As the fermentation progresses, nitrate will gradually be converted into nitrite under the action of certain microorganisms, thus causing potential food safety hazards. Therefore, removing or degrading nitrite in fermented foods is crucial for ensuring the quality of fermented foods. The TR19 strain described in the present invention has a very good degradation effect on nitrite.

[0072] Example 5

[0073] Ability of Pediococcus acidilactici TR19 to degrade cholesterol

[0074] The ferric ammonium sulfate method was used to determine the cholesterol content: After activating and culturing the strain, inoculate it into the MRS broth containing cholesterol solution at an inoculation amount of 2% (the MRS culture medium is added with 0.2% (W / V) of bile salt, sterilized at 121 °C for 15 min, prepare a cholesterol solution with a concentration of 0.01 g / mL with absolute ethanol, filter and sterilize it, and add it to the above sterilized medium at a volume fraction of 1.2% (V / V) so that the cholesterol content is 0.12 g / L). After culturing in a constant temperature incubator at 36 °C for 48 h, take samples. Pipette 2 mL of the cultured bacterial liquid, add absolute ethanol to 10 mL, and centrifuge at 4000 gCentrifuge for 15 min, pipette 2 mL of the supernatant into a clean test tube, add 2 mL of ammonium ferric sulfate color reagent, and after cooling, measure the absorbance at 560 nm, calculate the cholesterol residue amount / μg / mL (C), repeat each group of experiments three times, use the MRS (containing cholesterol) culture medium without inoculated strains as the control, measure the initial cholesterol concentration / μg / mL (C0) of fermentation, cholesterol degradation rate = (C0 - C) × 100 / C0, the results are shown in Figure 5 as follows.

[0075] It can be seen from Figure 5 that the cholesterol degradation experiment results show that after the strain TR19 is treated in the cholesterol-containing culture medium for 48 h, the cholesterol degradation rate can reach 56.34%, and the cholesterol content drops from the initial 120 μg / mL to 49.89 μg / mL, indicating that the strain TR19 has a certain degradation effect on cholesterol and can improve cardiovascular and cerebrovascular diseases such as coronary heart disease and atherosclerosis caused by excessive cholesterol.

[0076] The above is the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle described in the present invention, several improvements and modifications can be made, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A Pediococcus acidilactici with acid resistance, bile salt resistance and antibacterial activity ( Pediococcus acidilactici ), which was deposited in the China General Microbiological Culture Collection Center on July 17, 2024, with the deposit number of CGMCC NO. 31330.

2. Use of Pediococcus acidilactici with acid tolerance, bile salt tolerance and antibacterial activity as described in claim 1 in the preparation of a drug for degrading nitrite.

3. Use of Pediococcus acidilactici with acid tolerance, bile salt tolerance and antibacterial activity as described in claim 1 in the preparation of a drug for degrading cholesterol.

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