Pediococcus acidilactici with acid resistance, cholate resistance and bacteriostatic activity and application thereof

Abstract

The invention belongs to the technical field of probiotics, and particularly relates to pediococcus acidilactici with acid resistance, bile salt resistance and antibacterial activity and application of the pediococcus acidilactici. The pediococcus acidilactici TR19 has the preservation number of CGMCC NO.31330 and is classified and named as pediococcus acidilactici according to microorganisms. The strain has good acid resistance and bile salt resistance, and can be used for preparing probiotics for preventing and treating bacteria. Meanwhile, the strain has a relatively strong bacteriostatic effect on escherichia coli, bacillus cereus, staphylococcus aureus and salmonella typhimurium, in addition, the strain has a relatively good degradation capability on nitrite and cholesterol, and the applicability is relatively strong.

Description

Technical Field

[0001] The 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 an application thereof. 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 in turn causes imbalance in the intestinal flora of the human body and has an adverse effect on human health. The most common method for preventing and treating bacterial diseases is the use of antibiotics, but long-term excessive use of antibiotics can lead to bacterial resistance. According to research, almost all bacteria can now acquire various different 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 bacteria in traditional fermented foods. They specifically refer to a type of anaerobic or facultative anaerobic Gram-positive non-spore-forming bacteria that can produce a large amount of lactic acid by fermenting carbohydrates. Lactic acid bacteria are widely distributed in animals, plants, humans 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 industry. Lactic acid bacteria have the beneficial effects of maintaining the balance of human intestinal flora, relieving inflammation, and regulating the body's immunity. Moreover, the metabolites produced during its fermentation, such as acidic and polypeptide substances, not only give food a unique flavor, but also inhibit the growth of pathogenic microorganisms and spoilage bacteria. As a member of probiotics and normal intestinal flora, lactic acid bacteria must overcome the adverse environment of the mouth, stomach (high acidity, pepsin) and upper end of the digestive tract (bile salts, pancreatic enzymes) during the process of transmission from the mouth to the intestine after ingestion, so that it can exert beneficial effects on the host in the form of live bacteria. Therefore, the ability to tolerate the human gastrointestinal environment has become an important property and indicator for evaluating probiotics. In vitro effectiveness screening can reflect the actual survival ability of lactic acid bacteria in the real gastrointestinal environment to a certain extent.

[0004] Therefore, the study further screened out lactic acid bacteria that can survive in the digestive tract environment and have good antibacterial effects on common pathogenic microorganisms, thereby maintaining the dynamic balance of intestinal flora, which has important social significance and economic value.

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

[0006] For example, CN117210350A discloses a lactic acid Pediococcus and its application, which involves the extraction, identification and application fields of microorganisms. The lactic acid Pediococcus is derived from earthworms and is named: lactic acid Pediococcus 11029 strain. It was deposited in the General Microbiological Center of the China Microbiological Culture Collection Administration on December 16, 2021, with the deposit number: CGMCC: 24122. The lactic acid Pediococcus strain 11029 of this application has the advantages of good antibacterial effect, acid and bile resistance, good stress resistance, rapid growth and high biomass, but its tolerance and stress resistance are insufficient.

[0007] For example, CN108504601B discloses a newly isolated strain of Pediococcus acidilactici HEW-AP27, which is deposited in the General Microbiology Center of China Microorganism Culture Collection Committee (referred to as CGMCC, address: Institute of Microbiology, Chinese Academy of Sciences, No. 3, No. 1 Beichen West Road, Chaoyang District, Beijing, zip code: 100101), with a deposit number of CGMCC NO.15419 and a deposit date of March 7, 2018. The application also provides a method for preparing a live bacterial preparation of Pediococcus acidilactici, which specifically includes: using Pediococcus acidilactici as a fermentation strain, using an optimized post-fermentation process and fermentation medium, placing the culture in a tank after primary, secondary and tertiary cultivation, centrifuging to obtain active bacterial mud, adding a stabilizing protective agent, and then granulating the pellets through a granulator, and then adding a coating liquid in a coating machine for coating, and finally obtaining a live bacterial preparation of Pediococcus acidilactici. The invention's Pediococcus acidilactici HEW-AP27 is acid-resistant, bile-resistant, and high-temperature-resistant, has strong acid-producing properties, and can inhibit the growth and reproduction of pathogens. However, its ability to degrade nitrite and cholesterol has not been confirmed.

[0008] In view of this, the present invention is proposed. Summary of the invention

[0009] The purpose of the present invention is to provide a Pediococcus acidilactici with acid resistance, bile salt resistance and antibacterial activity and application thereof. The Pediococcus acidilactici obtained by the present invention has good degradation performance for 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: In the first aspect, an embodiment of the present invention provides a lactic acid Pediococcus having acid resistance, bile resistance and antibacterial activity, wherein the lactic acid Pediococcus was deposited in the General Microbiological Center of the China Microbiological Culture Collection Administration on July 17, 2024, with a deposit number of CGMCC NO.31330, and its microbial classification is named as lactic acid Pediococcus Pediococcusacidilactici .

[0011] In a preferred embodiment, the Pediococcus acidilactici is named TR19.

[0012] In a second aspect, an embodiment of the present invention provides a method for culturing Pediococcus acidilactici having acid resistance, bile resistance and antibacterial activity, comprising the following steps: The sweet mash and sterile physiological saline are mixed, homogenized, cultured on a plate after dilution, and the strain is obtained after separation and purification.

[0013] In a preferred embodiment, the homogenization is performed in a sterile homogenization bag.

[0014] In a preferred embodiment, the ratio of the sweet mash to sterile physiological saline is 25 g: (200-300) ml.

[0015] In a preferred embodiment, the homogenization comprises: Use a slapping homogenizer at 400-500 r / min for 2-4 minutes.

[0016] In a preferred embodiment, the dilution comprises diluting 10 times with physiological saline.

[0017] In a preferred embodiment, MRS agar medium is used for culturing.

[0018] In a preferred embodiment, the culture conditions are: temperature 30-40°C, time 36-72h.

[0019] In a preferred embodiment, the number of viable bacteria in the bacterial solution obtained after culture is 10 8 ~10 9 CFU / mL.

[0020] In a third aspect, an embodiment of the present invention provides the use of the above-mentioned Pediococcus acidilactici having acid resistance, bile salt resistance and antibacterial activity in degrading nitrite.

[0021] In a fourth aspect, an embodiment of the present invention provides the use of the above-mentioned Pediococcus acidilactici having acid resistance, bile salt resistance and antibacterial activity in degrading cholesterol.

[0022] In a fifth aspect, an embodiment of the present invention provides the use of the above-mentioned Pediococcus acidilactici having acid resistance, bile salt resistance and antibacterial activity in the preparation of a nitrite-degrading drug.

[0023] In a sixth aspect, an embodiment of the present invention provides the use of the above-mentioned Pediococcus acidilactici having acid resistance, bile salt resistance and antibacterial activity in the preparation of a cholesterol-degrading drug.

[0024] Compared with the prior art, the advantages and beneficial effects of the present invention are: 1. The Pediococcus acidilactici TR19 strain provided by the present invention has strong acid and bile resistance, as well as tolerance to artificial gastrointestinal fluid, and has the potential to survive and colonize in the human digestive tract environment.

[0025] 2. The Pediococcus acidilactici TR19 strain provided by the present invention has strong antibacterial activity against four pathogenic microorganisms, and has great potential in maintaining the dynamic balance of intestinal flora and preserving and preserving products.

[0026] 3. The Pediococcus acidilactici TR19 strain provided by the present invention has strong degradation performance on nitrite and cholesterol. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The lactic acid Pediococcus TR19 of the present invention was deposited in the General Microbiological Center of the China Microbiological Culture Collection Administration on July 17, 2024, with a deposit number of CGMCC NO.31330, and its microbial classification was named as lactic acid Pediococcus Pediococcusacidilactici .

[0028] Figure 1 : are microbiological morphological observation diagrams of the invented strain TR19, wherein a is the colony morphological characteristics of the strain after being cultured on an MRS plate for 48 hours, and b is the cell morphology of the strain observed under a 100x optical microscope after Gram staining.

[0029] Figure 2 The morphology of the inhibition zones of the invented strain TR19 against four indicator bacteria is observed, wherein a is the size of the inhibition zone of the strain TR19 against Escherichia coli, b is the size of the inhibition zone of the strain TR19 against Bacillus cereus, c is the size of the inhibition zone of the strain TR19 against Salmonella typhimurium, and d is the size of the inhibition zone of the strain TR19 against Staphylococcus aureus.

[0030] Figure 3 It is a diagram of the application of the invented strain TR19 in nitrite degradation, specifically a standard curve for nitrite determination (OD538nm absorbance value is the vertical axis, and nitrite content (μg) is the horizontal axis).

[0031] Figure 4 This is a diagram showing the application of the invented strain TR19 in nitrite degradation, specifically showing the degradation rate of nitrite by the strain TR19 in different time periods.

[0032] Figure 5 The standard curve with OD560nm absorbance as the ordinate and cholesterol content (μg / mL) as the abscissa can be used to detect the quantitative index of cholesterol content in samples. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] Unless otherwise specified, the raw materials used in the present invention are commercially available.

[0035] Example 1 Isolation, Screening, Identification and Preservation of Pediococcus acidilactici TR19 Sweet mash samples were purchased randomly from Dingxi City, Gansu Province. 25 g of the sample was weighed aseptically into a sterile homogenizing bag, and 225 mL of sterile saline was added. The sample was homogenized with a slapping homogenizer at 420 r / min for 2 min to make a 1:10 sample solution. 1 mL of the sample solution was diluted 10 times with sterile saline. 10 ~1 ~10 ~6 0.1 mL of each dilution was spread on the MRS plate. After anaerobic culture at 36°C for 72 h, the colony characteristics were carefully observed, and the lactic acid bacteria of different forms were separated and purified. The single colonies with good growth and different forms were picked by the plate streak method and repeatedly separated and purified on the MRS plate. 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 examined by Gram staining, and the morphology of the bacterial cells was observed under an optical microscope (100× objective lens). The strains with positive Gram staining were selected and preliminarily confirmed as suspected lactic acid strains, and physiological and biochemical tests and 16s rDNA identification were performed.

[0036] like Figure 1As shown in a, the colony morphology is: round, milky white, with neat edges, low ridges, moist, smooth, and opaque surface. Figure 1 The cell morphological characteristics shown in b are: Gram-positive, coccal, without spores, and without flagella. The physiological and biochemical test results are shown in Table 1 below.

[0037] Table 1 Physiological and biochemical characteristics of Pediococcus acidilactici TR19 Catalase activity - Sorbitol - lactose - Urease activity - fructose + Ribose + Amino acid decarboxylase activity - glucose + Rhamnose - Gelatinase activity - Galactose + sucrose - Indole test - Mannitol - Xylose + Nitrate reduction properties - maltose - Note: “+” indicates a positive reaction; “-” indicates a negative reaction Molecular biology identification results: The 16S rDNA sequence of lactic acid bacteria was 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℃5 min; 94℃1 min, 60℃1 min, 72℃1 min, 35 cycles, 72℃10 min. After the amplified product was detected by gel electrophoresis, it was sent to Shanghai Biotech Co., Ltd. for sequence determination. The results of the 16S rDNA gene sequence determination of the TR19 strain are as follows: The detected sequences were compared with the sequences in GenBank (http: / / www.ncbi.nlm.nih.gov) by NCBI Blast software and found that strain TR19 was Pediococcusacidilactici The homology of (ON631864.1) is 99.93%. Based on the principle that homology > 97% means they are of the same species, combined with the morphological characteristics, physiological and biochemical characteristics of the strain, the strain was finally identified as Pediococcus acidilactici ( Pediococcusacidilactici ), named Pediococcus acidilactici TR19 ( Pediococcusacidilactici TR19), deposited in the General Microbiology Center of China Microorganism Culture Collection Administration on July 17, 2024, with the deposit number CGMCC NO.31330.

[0038] Example 2 Acid and bile resistance experiments of Pediococcus acidilactici TR19 (1) Acid resistance test After the strain TR19 was activated, 10 mL of the culture solution was heated at 4°C for 5 000 hours. g The cells were collected by centrifugation for 15 min, and 2 mL of fresh MRS culture medium was added to the cells. After mixing, the bacterial suspension was inoculated into MRS liquid culture medium (adjusted with hydrochloric acid) with pH values ​​of 1.5, 2.5, and 3.5 at a 1% to 2% inoculum to control the number of viable cells to 10 8 ~10 9 CFU / mL range, with MRS (pH 6.4) liquid medium without pH adjustment as control, the culture medium was cultured at 36℃ for 3h, and the number of viable bacteria was calculated by MRS plate count method, and the determination was repeated 3 times, the survival rate = (N1 / N2) × 100%, where N1 is the number of viable bacteria (CFU / mL) after 3h of low pH MRS liquid culture; N2 is the initial number of viable bacteria (CFU / mL) measured on MRS control medium. The viable bacteria count and survival rate of TR19 strain under different pH conditions are shown in Table 2 below. The experimental results show that strain TR19 is intolerant to pH 1.5 and no colony grows. When the pH value is 2.5, the survival rate of strain TR19 is 35.23%, and the survival rate of strain TR19 increases to 79.22% under pH 3.5. The pH of gastric juice fluctuates greatly before and after eating. Generally, the pH is 1.5 when fasting. With the intake of food, the pH of the stomach rises to 3.0 or higher. The strain TR19 maintains a high survival rate under pH 2.5 and pH 3.5 conditions, and the number of viable bacteria can reach 10 8 CFU / mL, indicating that strain TR19 has strong acid tolerance.

[0039] Table 2 Acid resistance test of Pediococcus acidilactici TR19

[0040] (2) Bile salt tolerance test 1% activated TR19 bacterial suspension was added to MRS medium containing 0.00% (blank), 0.10%, 0.20% and 0.30% ox bile salt (w / v), cultured at 36°C, sampled after 4 hours, and the viable bacteria were counted by the coating counting method to calculate the survival rate. The determination was repeated 3 times, and the survival rate = (A / B) × 100%, where A is the number of viable bacteria (CFU / mL) in MRS culture medium with different bile salt concentrations after 4 hours, and B is the initial number of viable bacteria (CFU / mL) measured by MRS control medium. The number of viable bacteria and survival rate of TR19 strain 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 0.1%, 0.2% and 0.3% bile salt concentrations are 61.31%, 18.97% and 16.44%, respectively. The bile salt concentration in the intestine is in a dynamic state, generally between 0.03% and 0.3%. The strain TR19 has a certain survival rate at a bile salt concentration of 0.3%, and the number of viable bacteria remains at 10 8 CFU / mL, indicating that the strain also has good bile salt tolerance.

[0041] Table 3 Bile salt resistance test of Pediococcus acidilactici TR19

[0042] (3) Determination of resistance to artificial gastrointestinal fluid: The activated TR19 bacterial suspension was inoculated at a 1% inoculum size into 3 mL of artificial gastric fluid (NaCl (125 mmol / L), NaHCO3 (45 mmol / L), KCl (7 mmol / L) system, pepsin was added to make its concentration reach 3 g / L, and the pH was adjusted to 2.5), cultured at 36°C for 3 h, and the number of viable bacteria was determined. After 3 h of culture, the bacterial suspension was centrifuged and resuspended in an equal amount of artificial intestinal fluid (0.1% trypsin and 0.3% bile salt were added to the above buffer system, and the pH was adjusted to 8.0). The suspension was further cultured at 36°C for 4 h, and the number of viable bacteria after 4 h was determined. The ability of the strain to tolerate simulated gastrointestinal fluid was analyzed by survival rate, survival rate = (W / W0) × 100%, where W is the number of viable bacteria (CFU / mL) of the strain after 7 h of culture in the artificial gastrointestinal fluid environment, and W0 is the initial number of viable bacteria (CFU / mL). The viable bacterial count and survival rate of the TR19 strain 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 3 hours of treatment in simulated gastric fluid was 74.82%. After further treatment in the intestinal fluid for 4 hours, the viable bacterial count slightly decreased to 8.92Log CFU / mL. The survival rate after 7 hours of culture in the entire simulated gastrointestinal fluid system was 60.30%, indicating that strain TR19 has good tolerance to pepsin and trypsin. The simulated human gastrointestinal tract (GIT) assay is a standardized test system that aims to evaluate the survival rate of strains under conditions that simulate "normal" human stomach and small intestine. At present, there is no unified standard for GIT screening at home and abroad, but experimental data at home and abroad show that the critical value of the viable bacterial count for probiotic products to exert their functional properties is 10 6 CFU / mL. After the strain TR19 of the present invention was cultured in a simulated human gastrointestinal system for 7 hours, the number of viable bacteria reached the critical value requirement for the effectiveness of probiotics, indicating that the strain TR19 has good resistance to the gastrointestinal tract.

[0043] Table 4 Test on resistance of Pediococcus acidilactici TR19 to artificial gastrointestinal fluid

[0044] Example 3 Antibacterial activity of Pediococcus acidilactici TR19 Four common pathogenic microorganisms were selected as indicator bacteria, including two strains of enteric bacteria Escherichia coli and Salmonella typhimurium, which belong to Gram-negative bacteria, and two strains of Gram-positive bacteria Staphylococcus aureus and Bacillus cereus. The antibacterial activity of the fermentation supernatant of TR19 strain was determined by the Oxford cup method: 20 mL of nutrient agar was poured into a 9-cm diameter culture dish, and the indicator bacteria suspension (OD600nm =0.1) 0.1mL was evenly spread on the nutrient plate, and dried in the clean bench for 5 min. The Oxford cup was placed on the plate at an equal distance, and 200μL lactic acid bacteria culture supernatant was added. The MRS medium without bacterial solution was used as the control. The plate was cultured at 36℃ for 12h~24h, and the size of the inhibition zone was observed and the diameter of the inhibition zone was measured (mm). The antibacterial activity of lactic acid strains against common intestinal pathogens was analyzed by comparing the size of the inhibition zone. The results are shown in Table 5 and Figure 2 As shown, Figure 2 In the figure, ad represents the size of the inhibition zone of strain TR19 against indicator bacteria Escherichia coli, Bacillus cereus, Salmonella typhimurium and Staphylococcus aureus. The results showed that strain TR19 had strong antibacterial activity against the four indicator bacteria, and the diameters of the inhibition zones were all above 20 mm. Among them, strain TR19 had the strongest antibacterial activity against Salmonella typhimurium, with an inhibition zone diameter of 25.93 mm.

[0045] Table 5 Antibacterial activity of Pediococcus acidilactici TR19

[0046] Example 4 Nitrite degradation ability of Pediococcus acidilactici TR19 After the strain was activated and cultured, it was inoculated into MRS liquid medium with a NaNO2 content of 125 mg / L at a 2% inoculum and cultured in the dark at 36°C. The fermentation broth was taken at 0h, 6h, 12h, 24h, 36h, and 48h, respectively, and incubated at 4°C, 8000 g , centrifuge for 5 min, take the supernatant, and determine the nitrite content in the fermentation broth by referring to the naphthylethylenediamine hydrochloride method in GB 5009.33~2016 "National Food Safety Standard Determination of Nitrite and Nitrate in Food" (see Appendix 1 for the main reagents used in the experiment), measure the absorbance at a wavelength of 538 nm, and measure 3 times in parallel in each time period. According to the degradation rate of sodium nitrite, the ability of lactic acid bacteria to degrade nitrite was evaluated. Nitrite degradation rate (%) = (B0-B) × 100 / B0, where B0 represents the initial content of NaNO2 in the MRS culture medium without inoculation of strains (mg / kg), and B represents the content of NaNO2 in the fermentation supernatant at different times after inoculation of strains (mg / kg).

[0047] Results Figure 3 and Figure 4As shown in the figure, the results of the nitrite degradation experiment show that strain TR19 has a very good degradation effect on sodium nitrite. After being treated in a medium containing sodium nitrite for 36 hours, the degradation rate reached more than 99%, and almost all of the sodium nitrite was degraded. Compared with existing research reports at home and abroad, strain TR19 degrades nitrite at a faster rate. After 6 hours of cultivation, the nitrite degradation rate is about 30%, and the degradation rate after 12 hours reaches 80%. Nitrite is an important factor causing fermented food safety. Vegetables and crops are planted because of the application of a large amount of nitrogen fertilizer, so that their roots contain a large amount of nitrate. As the fermentation proceeds, nitrate will gradually be converted into nitrite under the action of certain microorganisms, thereby causing potential food safety hazards. Therefore, removing or degrading nitrite in fermented food is crucial to the quality assurance of fermented food. The TR19 strain described in the present invention has a very good degradation effect on nitrite.

[0048] Example 5 Cholesterol degradation ability of Pediococcus acidilactici TR19 The cholesterol content was determined by the ammonium ferric sulfate method: after the strain was activated and cultured, it was inoculated at a 2% inoculum into MRS broth containing a cholesterol solution (0.2% (W / V) ox bile salt was added to the MRS culture medium, sterilized at 121°C for 15 min, a cholesterol solution with a concentration of 0.01 g / mL was prepared with anhydrous ethanol, filtered and sterilized, and added to the above sterilized culture medium at a concentration of 1.2% (V / V) to make the cholesterol content 0.12 g / L.), cultured in a 36°C constant temperature incubator for 48 h, sampled, 2 mL of the cultured bacterial solution was taken, anhydrous ethanol was added to 10 mL, and incubated at 4000 g Centrifuge for 15 min, pipette 2 mL of supernatant into a clean test tube, add 2 mL of ammonium ferric sulfate colorimetric agent, and after cooling, measure the absorbance at 560 nm to calculate the residual cholesterol / μg / mL (C). Repeat each test three times, using MRS (cholesterol-containing) culture medium without inoculation as the control, and measure the initial cholesterol concentration / μg / mL (C0) of fermentation. Cholesterol degradation rate = (C0-C) × 100 / C0. For results, see Figure 5 shown.

[0049] Depend on Figure 5 It can be seen that the results of the cholesterol degradation experiment show that after the strain TR19 was treated in the cholesterol-containing culture medium for 48 hours, the cholesterol degradation rate could reach 56.34%, and the cholesterol content dropped from the initial 120μg / mL to 49.89μg / 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.

[0050] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A lactic acid Pediococcus with acid resistance, bile resistance and antibacterial activity, wherein the lactic acid Pediococcus was deposited in the General Microbiological Center of China Microbiological Culture Collection Administration on July 17, 2024, with a deposit number of CGMCC NO.31330.

2. A method for culturing Pediococcus acidilactici having acid resistance, bile resistance and antibacterial activity as claimed in claim 1, characterized in that: The following steps are involved: The sweet mash and sterile physiological saline are mixed, homogenized, diluted, and then streaked on a plate for culture, and the strain is obtained after separation and purification.

3. The method for culturing Pediococcus acidilactici having acid resistance, bile resistance and antibacterial activity according to claim 2, characterized in that: Homogenization is performed in a sterile homogenization bag.

4. The method for culturing Pediococcus acidilactici having acid resistance, bile resistance and antibacterial activity according to claim 2, characterized in that: The dosage ratio of the sweet mash to sterile physiological saline is 25g: (200-300)ml.

5. The method for culturing Pediococcus acidilactici having acid resistance, bile resistance and antibacterial activity according to claim 2, characterized in that: The homogenization comprises: Use a slapping homogenizer at 400-500 r / min for 2-4 minutes; And / or, the dilution comprises diluting 10 times with physiological saline; And / or, culture is performed using MRS agar medium.

6. The method for culturing Pediococcus acidilactici having acid resistance, bile resistance and antibacterial activity according to claim 2, characterized in that: The culture conditions are: temperature 30-40°C, time 36-72h; And / or, the number of viable bacteria in the bacterial solution obtained after culturing is 10 8 ~10 9 CFU / mL.

7. Use of the acid-resistant, bile-resistant and antibacterial Pediococcus acidilactici bacterium according to claim 1 in degrading nitrite.

8. Use of the acid-resistant, bile-resistant and antibacterial Pediococcus acidilactici as claimed in claim 1 in degrading cholesterol.

9. Use of the acid-resistant, bile-resistant and antibacterial Pediococcus acidilactici according to claim 1 in the preparation of a nitrite-degrading drug.

10. Use of the acid-resistant, bile-resistant and antibacterial Pediococcus acidilactici according to claim 1 in the preparation of cholesterol-degrading drugs.

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