Pediococcus acidilactici and use thereof

Abstract

The application discloses a pediococcus acidilactici and application thereof, and relates to the technical field of microorganisms. The pediococcus acidilactici is pediococcus acidilactici Mei.1103.1, the preservation unit is the China General Microbiological Culture Collection Center, the preservation number is CGMCC NO.32564, the preservation date is November 11, 2024, and the preservation address is the Institute of Microbiology, Chinese Academy of Sciences, No.3, Yihuangyuan, Beichenxilu, Chaoyang District, Beijing. The application also provides application of the pediococcus acidilactici in preparation of products for reducing uric acid, preventing / treating hyperuricemia, immune regulation, preventing / treating kidney injury, preventing / treating fatty liver and fermented dry rice flour. The bacteria can reduce uric acid, relieve hyperuricemia, regulate blood lipids, repair kidney and liver injury caused by hyperuricemia, and increase the content of volatile flavor compounds in fermented dry rice flour.

Description

Technical Field

[0001] The present invention relates to the technical field of microorganisms, and in particular to Pediococcus acidilactici and applications thereof. Background Art

[0002] Hyperuricemia (HUA) is a metabolic disease caused by excessive uric acid production or impaired uric acid excretion. Its main causes include purine metabolism disorders, renal insufficiency, or genetic factors. Clinically, hyperuricemia is usually diagnosed by measuring the patient's fasting serum uric acid level. A fasting serum uric acid level exceeding 420 μmol / L, regardless of gender or whether measured on different days, is considered hyperuricemia. Hyperuricemia can progress from early benign, asymptomatic hyperuricemia to more severe chronic gouty arthritis and may ultimately lead to renal failure, hypertension, hyperlipidemia, type 2 diabetes, and cardiovascular atherosclerosis.

[0003] In recent years, with improvements in living standards and changes in diet and lifestyle, the prevalence of hyperuricemia has increased significantly worldwide. Currently, drug therapy and dietary intervention are the two main treatment strategies for hyperuricemia. Although medications have alleviated hyperuricemia to some extent, some are expensive and may cause serious side effects. Furthermore, approximately half of cases of asymptomatic hyperuricemia do not ultimately develop gout, making many patients resistant to drug treatment. Dietary intervention, on the other hand, has a significant impact on patients' quality of life. In recent years, researchers have begun exploring non-drug uric acid-lowering therapies, including lactic acid bacteria, plant extracts, dietary fiber, and oligopeptides, in the hope of providing patients with hyperuricemia with a mild, non-toxic, and effective treatment. Compared with traditional drug treatments, lactic acid bacteria, as a natural microorganism, offer advantages such as safety, independence, and the absence of side effects, and are therefore attracting increasing attention.

[0004] Rice noodles, a popular traditional food, enjoy a huge consumer market in my country and around the world. Traditional rice noodle production primarily uses early indica rice, which is high in amylose, rather than late indica rice, which boasts a higher amylopectin content and a richer flavor. This results in limited flavor, making it difficult to meet consumers' increasingly diverse and high-quality demands. In the food industry, microbial fermentation technology has been widely used to improve food quality and enhance flavor. Microbial fermentation can decompose and transform macromolecules in raw materials, producing a variety of volatile flavor compounds that impart a unique flavor. In some dry-cured meat products, such as fish and goose, microbial activity enriches them with aliphatic unsaturated aldehydes with carbon chain lengths of C6-C12, enhancing their flavor. However, existing fermented rice noodle production technologies require short fermentation times, resulting in predominantly saturated volatile aldehydes, whose flavor thresholds are often higher than those of unsaturated aldehydes, resulting in a less robust flavor. Furthermore, the natural fermentation process can lead to significant variations in microbial community structure, making it susceptible to contamination by other bacteria, resulting in unstable flavor and quality. Purified strain fermentation offers a solution to this problem. However, the existing fermentation bacteria used are difficult to efficiently produce aliphatic unsaturated aldehydes with a carbon chain length of C6-C12, such as trans-2-decenal and 2-undecenal, which have grassy, ​​fatty, and fruity aromas. Summary of the Invention

[0005] The present invention aims to address at least one of the technical problems existing in the prior art. It provides Pediococcus acidilactici and its applications. Specifically, Pediococcus acidilactici Mei.1103.1 has the efficacy of degrading nucleosides, lowering uric acid, alleviating hyperuricemia, regulating the immune system, preventing / treating kidney damage, and preventing / treating fatty liver, and can be used to prepare fermented dry rice noodles. In vitro and in vivo experiments have demonstrated the uric acid-lowering efficacy of this bacterium, which can alleviate hyperuricemia, regulate blood lipids, repair kidney and liver damage caused by hyperuricemia, and increase the content of volatile flavor compounds in fermented dry rice noodles. This provides the technical solution of the present invention and achieves its objectives.

[0006] The technical solutions of the present invention are as follows:

[0007] A first aspect of the present invention provides Pediococcus acidilactici, which is Pediococcus acidilactici Mei.1103.1, deposited with the China General Microbiology Center of the China Culture Collection Administration of Microorganisms (CGMCC), with a deposit number of CGMCC NO.32564, a deposit date of November 11, 2024, and an address of the Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing.

[0008] Furthermore, the degradation rate of inosine and guanosine by the lactic acid bacteria was 100% within 30 minutes, and the degradation rates of inosine and guanosine by the lactic acid bacteria were 6.67 mg / (L·min) and 6.67 mg / (L·min), respectively.

[0009] Furthermore, the P. acidilactici bacteria exhibited resistance to acid, bile salts, and gastrointestinal digestion. Specifically, the survival rates of the bacteria at pH 2.0 and pH 3.0 were 81.28% and 100%, respectively; the survival rates of the bacteria at 0.15 wt% bile salts and 0.3 wt% bile salts were 93.77% and 90.55%, respectively; and the survival rates of the bacteria in artificial simulated gastric fluid and artificial simulated intestinal fluid were 87.13% and 79.08%, respectively.

[0010] Furthermore, the Pediococcus acidilactici has an excellent antibacterial effect. Specifically, the Pediococcus acidilactici can inhibit several common pathogenic bacteria, including Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, and Salmonella.

[0011] Furthermore, the biological characteristics of the lactic acid bacteria are Gram-positive. When cultured in MRS medium at 37° C. for 24 h, the colonies are white, round, with a moist surface, opaque, and neat edges; the bacteria are spherical.

[0012] A second aspect of the present invention provides a lactic acid bacteria agent, wherein the active ingredient of the lactic acid bacteria agent includes the Pediococcus acidilactici.

[0013] The third aspect of the present invention provides a freeze-dried lactic acid bacteria powder, wherein the active ingredient of the freeze-dried lactic acid bacteria powder includes the Pediococcus acidilactici.

[0014] Optionally, the freeze-dried lactic acid bacteria powder further comprises a freeze-dried protective agent, and the freeze-dried protective agent comprises the following components: skim milk powder, sodium L-ascorbate, sodium glutamate, and xylo-oligosaccharides.

[0015] The fourth aspect of the present invention provides the use of the Pediococcus acidilactici or the lactic acid bacteria agent or the lactic acid bacteria freeze-dried powder in the preparation of a degraded nucleoside product or an immunomodulatory product.

[0016] Specifically, the degradation rate of inosine and guanosine by Pediococcus acidilactici within 30 minutes is 100%; the immunomodulatory product has at least one of the following characteristics: 1) increasing the level of the anti-inflammatory factor IL-10; 2) reducing the level of the pro-inflammatory factors IL-6 and / or IL-1β and / or TNF-α.

[0017] The fifth aspect of the present invention provides the use of the Pediococcus acidilactici or the lactic acid bacteria agent or the lactic acid bacteria freeze-dried powder in the preparation of products for lowering uric acid, preventing and / or treating hyperuricemia.

[0018] Specifically, the product has the ability to lower serum uric acid levels.

[0019] A sixth aspect of the present invention provides the use of Pediococcus acidilactici or the lactic acid bacteria agent or the lactic acid bacteria freeze-dried powder in the preparation of a product for preventing and / or treating kidney damage or a product for preventing and / or treating fatty liver.

[0020] Specifically, the product for preventing and / or treating kidney damage has the ability to reduce serum creatinine and / or urea nitrogen levels.

[0021] Specifically, the product for preventing and / or treating fatty liver can reduce serum triglyceride and / or low-density lipoprotein and / or high-density lipoprotein levels.

[0022] The seventh aspect of the present invention provides the use of the lactic acid bacteria or the lactic acid bacteria agent or the lactic acid bacteria freeze-dried powder in the preparation of fermented dry rice noodles, wherein the use includes increasing the content of volatile flavor compounds trans-2-decenal and 2-undecenal in the fermented dry rice noodles, increasing the lactic acid content in the fermentation broth and lowering the pH of the fermentation broth.

[0023] An eighth aspect of the present invention provides a method for preparing fermented dry rice noodles, comprising the following steps:

[0024] S1, soaking the washed and dried late indica rice in water, the amount of water added is 1.0 times to 1.5 times the dry weight of the late indica rice, and inoculating the lactic acid bacteria or the lactic acid bacteria agent or the lactic acid bacteria freeze-dried powder therein for fermentation; wherein the inoculation amount of the lactic acid bacteria is 10 5 CFU / g~10 7 CFU / g, fermentation temperature is 25℃~35℃, fermentation time is 7 days~15 days, and fermentation pH is 3~3.8;

[0025] S2, after fermentation is completed, the fermented late indica rice is subjected to grinding, filter pressing, dough making, steaming, powder squeezing, powder cooking, cooling, powder panning, and drying to make fermented dry rice noodles.

[0026] A ninth aspect of the present invention provides fermented dry rice noodles obtained by the preparation method, wherein the contents of the volatile flavor compounds trans-2-decenal and 2-undecenal in the fermented dry rice noodles are 1277.05 μg / kg and 313.47 μg / kg, respectively.

[0027] The present invention has at least one of the following beneficial effects:

[0028] 1. The present invention isolates a strain of Pediococcus acidilactici Mei.1103.1 from the fermentation broth of Luocheng Zhafen. This strain can efficiently degrade inosine and guanosine, and also has excellent acid resistance, bile salt tolerance, and antibacterial properties. It does not have pathogenic genes, virulence genes, or drug-resistance genes, is sensitive to antibiotics, and is non-hemolytic. It is a safe probiotic that can be used in food. In addition, the Pediococcus acidilactici Mei.1103.1 can effectively lower uric acid and alleviate hyperuricemia; it has a protective effect on kidney damage, can lower blood lipids and protect the liver, and has anti-inflammatory and immune-regulating effects.

[0029] 2. The present invention also utilizes Pediococcus acidilactici in the preparation of fermented dry rice noodles. Late indica rice fermented with the present invention's Pediococcus acidilactici Mei.1103.1 produces high concentrations of trans-2-decenal and 2-undecenal when made into dry rice noodles. The present invention's Pediococcus acidilactici Mei.1103.1 has a strong acid-producing capacity, stabilizes the rice noodle fermentation process, reduces the risk of contamination by other bacteria, and ensures the stability of the flavor and quality of the fermented dry rice noodles.

[0030] The lactic acid Pediococcus of the present invention is Pediococcus acidilactici Mei.1103.1, the preservation unit is the General Microbiology Center of the China Culture Collection Administration of Microorganisms (CGMCC for short), the preservation number is CGMCCNO.32564, the preservation date is November 11, 2024, and the preservation address is the Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The growth curve of Pediococcus acidilactici Mei.1103.1 in Example 2 of the present invention ( Figure 1 A in the figure), Gram staining ( Figure 1 B in the figure), scanning electron microscope image ( Figure 1 C in );

[0032] Figure 2 The stress resistance of Pediococcus acidilactici Mei.1103.1 in Example 3 of the present invention;

[0033] Figure 3 This is the chromosome circle map of Pediococcus acidilactici Mei.1103.1 in Example 5 of the present invention;

[0034] Figure 4 This is a circle diagram of plasmid 1 of Pediococcus acidilactici Mei.1103.1 in Example 5 of the present invention;

[0035] Figure 5This is a circle diagram of plasmid 2 of Pediococcus acidilactici Mei.1103.1 in Example 5 of the present invention;

[0036] Figure 6 is the hemolytic result in Example 5 of the present invention, Figure 6 A in the figure is the positive control Staphylococcus aureus. Figure 6 B in the figure is Pediococcus acidilactici Mei.1103.1;

[0037] Figure 7 The results of the uric acid-lowering zebrafish experiment with Pediococcus acidilactici Mei.1103.1 in Example 6 of the present invention are as follows;

[0038] Figure 8 These are the three results of rat renal function in Example 6 of the present invention, Figure 8 A in is the serum uric acid level, Figure 8 B in the table is the serum creatinine level. Figure 8 C in is the serum urea nitrogen level;

[0039] Figure 9 The appearance of rat kidney in Example 6 of the present invention ( Figure 9 A) and HE staining results ( Figure 9 B in the );

[0040] Figure 10 These are the four results of rat blood lipids in Example 6 of the present invention. Figure 10 A in the equation is the total cholesterol level. Figure 10 B in the figure is the triglyceride level. Figure 10 The C in the equation is the high-density lipoprotein level. Figure 10 D in the figure represents the low-density lipoprotein level;

[0041] Figure 11 The appearance of rat liver in Example 6 of the present invention ( Figure 11 A) and HE staining results ( Figure 11 B in the );

[0042] Figure 12 The results of rat kidney inflammatory factors in Example 6 of the present invention are as follows: Figure 12 A in the expression is IL-1β. Figure 12 B in the expression is IL-6. Figure 12 The C in it is TNF-α, Figure 12 The D in the expression is IL-10.

[0043] Figure 13 The pH value change curves during the fermentation process in Example 8 of the present invention and Comparative Example 1 are shown.

[0044] Figure 14 The lactic acid content change curves during the fermentation process in Example 8 of the present invention and Comparative Example 1 are shown. DETAILED DESCRIPTION

[0045] In order to make the technical problems solved by the present application, technical solutions and beneficial effects clearer, the present application will be further described in detail below with reference to the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and not to limit the present application.

[0046] The MRS liquid medium (Qingdao Gaosike Industrial Park Haibo Biotechnology Co., Ltd.) in the embodiment of the present application is composed of the following components: glucose 20 g / L, peptone 10 g / L, beef infusion powder 8.0 g, yeast infusion powder 5 g, diammonium hydrogen citrate 2 g / L, dipotassium hydrogen phosphate 2 g / L, ammonium acetate 5 g / L, magnesium sulfate 0.2 g / L, manganese sulfate 0.04 g / L, Tween-80 1 g / L, and the pH is 5.7±0.2. The preparation method is as follows: weigh 52.24 g of the medium sample, dissolve in 1 L of distilled water by heating, and sterilize at 121℃ for 15 min, and then store for use.

[0047] The MRS solid medium (Qingdao Gaosike Industrial Park Haibo Biotechnology Co., Ltd.) in the embodiment of the present application is composed of the following components: glucose 20 g / L, peptone 10 g / L, beef infusion powder 8.0 g, yeast infusion powder 5 g, diammonium hydrogen citrate 2 g / L, dipotassium hydrogen phosphate 2 g / L, ammonium acetate 5 g / L, magnesium sulfate 0.2 g / L, manganese sulfate 0.04 g / L, Tween-80 1 g / L, agar 15 g / L, and the pH is 5.7±0.2. The preparation method is as follows: weigh 66.2 g of the medium sample, dissolve in 1 L of distilled water by heating, and sterilize at 121℃ for 20 min, and then store for use.

[0048] If the specific experimental steps or conditions are not specified in the examples, the operations or conditions can be performed according to the conventional experimental steps described in the literature in the art. The raw materials or instruments used are conventional products that can be obtained by purchase, including but not limited to the raw materials or instruments used in the examples of the present application.

[0049] The present application will be further described in detail below with specific examples, but the present application is not limited to the following specific examples.

[0050] Example 1 Screening and identification of potential uric acid-lowering bacterial strains

[0051] 1. Isolation of strains

[0052] The present invention screened the Pediococcus acidilactici strain Mei.1103.1 from the fermentation broth of Zhafen in Luocheng, Jiangxi Province. The specific acquisition method involved taking an appropriate amount of the fermentation broth and placing it in sterile nutrient broth at 37°C for strain enrichment. Subsequently, a suitable concentration gradient was selected and inoculated onto MRS solid medium. Strains with distinct colony morphology, size, and color were selected and streaked onto plates. This streaking process was repeated multiple times to obtain pure lactic acid bacteria cultures. A total of 20 strains of lactic acid bacteria were isolated, designated Mei.1103.1 to Mei.1103.20, and the isolated strains were stored in glycerol tubes.

[0053] 2. Screening of strains with nucleoside degradation ability

[0054] The isolated strains were activated in MRS liquid medium at 37°C for 24 h. The activated fermentation broth was centrifuged at 5000 rpm for 10 min at 4°C to obtain a precipitate, which was washed three times with phosphate buffer and resuspended in potassium dihydrogen phosphate solution containing purine nucleosides (0.2 g / L inosine and 0.2 g / L guanosine, added at a 4% concentration). The mixture was incubated anaerobically at 37°C for 30 min. Perchloric acid was then added as a terminator at a ratio of 9:1 (v / v) and filtered through a 0.22 μm filter. 20 μL of the filtrate was analyzed by high-performance liquid chromatography (HPLC, 1260 Series, Agilent Technologies, CA, USA). Chromatographic conditions included a Sunfire C18 column (5 μm, 250 mm × 4.6 mm; water), a flow rate of 1 mL / min, a column temperature of 25°C, and a UV detector at 254 nm. The mobile phase consisted of methanol-phosphate (1:99 volume ratio). The degradation rate of nucleosides is calculated as follows:

[0055]

[0056] Among them, C 空白 The nucleoside content of the supernatant of the reaction solution without adding lactic acid bacteria, C 样品 They are the nucleoside contents after adding lactic acid bacteria.

[0057] The degradation efficiency of nucleosides by all lactic acid bacteria varied, ranging from 1.77% to 100%, as shown in Table 1. The screened strain Mei.1103.1 had the best nucleoside degradation ability, completely degrading inosine and guanosine within 30 min. The degradation rates of inosine and guanosine by Pediococcus acidilactici were 6.67 mg / (L·min) and 6.67 mg / (L·min), respectively.

[0058] Table 1

[0059] strain Inosine degradation rate (%) Guanosine degradation rate (%) strain Inosine degradation rate (%) Guanosine degradation rate (%) Mei.1103.1 100.00± 0.00 100.00± 0.00 Mei.1103.11 11.08±5.21 45.19±5.33 Mei.1103.2 44.71±2.94 78.08±4.28 Mei.1103.12 22.01±3.99 10.12±4.67 Mei.1103.3 86.17±0.76 94.37±3.08 Mei.1103.13 95.50±2.54 73.93±9.94 Mei.1103.4 6.24±1.83 48.64±5.59 Mei.1103.14 29.07±9.01 73.37±2.83 Mei.1103.5 19.62±1.51 18.81±1.37 Mei.1103.15 69.49±1.93 64.44±4.05 Mei.1103.6 32.63±6.14 3.60±3.58 Mei.1103.16 38.19±0.84 58.85±5.98 Mei.1103.7 78.24±3.00 69.24±8.66 Mei.1103.17 77.28±0.95 41.77±8.21 Mei.1103.8 57.66±5.44 31.93±3.64 Mei.1103.18 37.55±4.14 85.52±5.23 Mei.1103.9 19.59±2.08 17.13±5.47 Mei.1103.19 50.16±1.61 42.58±8.32 Mei.1103.10 1.77±1.13 28.09±6.49 Mei.1103.20 79.78±3.07 95.23±2.91

[0060] 3. Strain identification

[0061] DNA from the screened strain Mei.1103.1 was extracted using a kit and amplified by PCR. The strain was then sent to Shanghai Paisonno Biotechnology Co., Ltd. for 16S rRNA gene sequencing. Sequencing results were compared using BLAST tools in NCBI to confirm the strain's species identity, confirming it as Pediococcus acidilactici. This strain, Mei.1103.1, was deposited with the General Microbiology Center of the China General Microbiology Culture Collection (CGMCC) under the deposit number CGMCC No. 32564, on November 11, 2024, at the Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing.

[0062] The 16S rRNA sequence of the bacterium is shown in SEQ ID NO: 1:

[0063]

[0064] Example 2 Growth Characteristics and Cell Morphology Observation of Pediococcus acidilactici Mei.1103.1

[0065] 1. Growth curve determination of Pediococcus acidilactici Mei.1103.1

[0066] 200 μL of the glycerol stock of Pediococcus acidilactici screened in Example 1 was inoculated into 50 mL of MRS liquid medium and cultured at 37°C and 160 r / min until the bacterial solution became turbid. The same activation operation was repeated twice. The activated Pediococcus acidilactici Mei.1103.1 was inoculated into MRS liquid medium and cultured at 37°C and 160 r / min for 30 h. Samples were taken at 0 h, 2 h, 4 h, 6 h, 8 h, 10 h, 12 h, 14 h, 16 h, 18 h, 20 h, 22 h, 24 h, 28 h, and 30 h, and the OD value of the culture solution was measured. 600 The result is shown in Figure 1 A. The Pediococcus acidilactici Mei.1103.1 of the present invention enters the logarithmic phase at around 8 h and enters the stable phase at around 24 h.

[0067] 2. Gram staining of Pediococcus acidilactici Mei.1103.1

[0068] Use an inoculation loop to pick up a small amount of lactic acid Pediococcus and spread it evenly on a clean glass slide, heat it with a flame to fix it, stain it with ammonium oxalate crystal violet for 1 minute, rinse it with tap water to remove the floating color, stain it with iodine-potassium iodide solution for 1 minute, pour off the excess solution, decolorize it with 95% ethanol for 30 seconds, and then counterstain it with safranin dye for 30 seconds. After decolorization, observe the morphology under an electron microscope with a 100x oil lens. The specific morphology is as follows. Figure 1 As shown in B, the Pediococcus acidilactici Mei.1103.1 obtained in the present invention is a Gram-positive bacterium.

[0069] 3. Scanning electron microscopy observation of Pediococcus acidilactici Mei.1103.1

[0070] The lactic acid bacteria Mei.1103.1 was activated and cultured in MRS liquid medium at 37 ℃ for 24 h. The activated fermentation broth was centrifuged at 5000 rpm for 10 min at 4 ℃ to obtain a precipitate, which was then washed three times with phosphate buffer. 1 mL of 2.5% glutaraldehyde solution was added, mixed thoroughly, fixed at 4 ℃ for 4 h, and then centrifuged at 5000 rpm for 10 min at 4 ℃ to obtain a precipitate. The precipitate was dehydrated with ethanol solutions of gradient volume concentrations (including five concentrations of 20%, 40%, 60%, 80%, and 100%), treated for 10 min at each concentration, and centrifuged at 5000 rpm for 3 min. The cell morphology was observed using a scanning electron microscope. The results are shown in Figure 2. Figure 1As shown in C in FIG, the Pediococcus acidilactici Mei.1103.1 obtained in the present invention is a spherical bacterium.

[0071] Example 3: Excellent stress resistance of Pediococcus acidilactici Mei.1103.1

[0072] Pediococcus acidilactici Mei.1103.1 was activated and cultured in MRS liquid medium at 37 ℃ for 24 h, inoculated in MRS liquid medium at pH 2.0 and pH 3.0 for 3 h to evaluate its tolerance to acidic conditions, inoculated in MRS medium containing 0.15 wt% and 0.3 wt% bile salts for 3 h to evaluate its tolerance to bile salts, and inoculated in artificial simulated gastric fluid and artificial simulated intestinal fluid in vitro for 2 h to evaluate its tolerance to the gastrointestinal environment.

[0073] Artificial simulated gastric fluid: Prepare 40 mL of gastric electrolyte solution according to Table 2 and adjust the pH to 3. Then add pepsin and lipase at 2000 U / mL and 60 U / mL respectively. After they are evenly dissolved, sterilize the microporous filter membrane and set aside.

[0074] Artificial simulated intestinal fluid: Prepare 80 mL of intestinal electrolyte solution according to Table 2 and adjust its pH to 7. Then add pancreatic enzyme and bile salt at the amounts of 100 U / mL and 0.3 mg / mL. After they are evenly dissolved, sterilize the microporous filter membrane and set aside.

[0075] Table 2

[0076] Components Artificial simulated gastric fluid electrolytes Artificial simulated intestinal fluid electrolytes KCl 0.69 g 1.36 g <![CDATA[KH2PO4]]> 0.09 g 0.16 g <![CDATA[NaHCO3]]> 1.25 g 8.5 g NaCl 1.18 g 1.92 g <![CDATA[MgCl2(H2O)6]]> 0.04 g 0.22 g <![CDATA[(NH4)2CO3]]> 0.05 g - <![CDATA[CaCl2(H2O)2]]> 0.10 g 0.08 g <![CDATA[H2O]]> 36.69 g 67.76 g

[0077] The calculation formula is as follows:

[0078] Where: CFUNt - viable bacterial count after treatment with acid / bile salt / artificial simulated gastric fluid / artificial simulated intestinal fluid, CFUN0 - original viable bacterial count;

[0079] The results are as follows Figure 2 As shown. Figure 2 It can be seen that the Pediococcus acidilactici obtained by the present invention has excellent acid resistance, bile salt resistance and gastrointestinal digestion resistance.

[0080] Example 4: Excellent antibacterial properties of Pediococcus acidilactici Mei.1103.1

[0081] The cell-free supernatant of Pediococcus acidilactici Mei.1103.1 was tested for its inhibitory activity against four common pathogens (Listeria monocytogenes, Escherichia coli, Staphylococcus aureus, and Salmonella) using the Oxford cup method. The strain obtained in the present invention, Pediococcus acidilactici Mei.1103.1, exhibited significant antibacterial activity against all four common pathogens. The results are shown in Table 3 below.

[0082] Table 3

[0083]

[0084] Example 5 Safety evaluation of Pediococcus acidilactici Mei.1103.1

[0085] The complete genome of Pediococcus acidilactici Mei.1103.1 was determined and analyzed using whole genome sequencing technology, and the whole genome sequence was submitted to Genebank with project number PRJNA1242910 and biological sample number SAMN47610829. The results showed that the genome of Pediococcus acidilactici Mei.1103.1 consisted of one chromosome and two plasmids, with a total genome length of 2,142,273 bp. The genome contained 2084 coding genes, accounting for 85.55% of the genome sequence. These genes are closely related to the physiological function, metabolic pathway and environmental adaptability of the strain. The average GC content of the genome is 40.01%, which is consistent with the typical genome characteristics of lactic acid bacteria, indicating that the strain has a relatively stable genome structure. Genome assembly analysis showed that the genome of Pediococcus acidilactici Mei.1103.1 has good quality and high integrity. In order to further describe the structural characteristics of the genome of the strain, the detailed genome assembly statistical data are shown in Table 4 below. The circular structure map of the genome Figures 3 to 5 ) directly shows the distribution of each functional region in the genome.

[0086] Table 4

[0087]

[0088] 1. Pathogenic / virulence gene analysis of Pediococcus acidilactici Mei.1103.1

[0089] The obtained sequencing data were annotated using Prokka and RAST tools to identify potential pathogenic / virulence gene regions, and these genes were aligned with known pathogenic gene databases using BLAST tools to screen genes related to foodborne pathogens, pathogenicity or virulence, including but not limited to: enterotoxin genes (such as enterotoxin), collagenase genes (such as collagenase), invasive genes (such as invA), cytolysin genes (such as cytolysin). According to the relevant standards and index requirements in the “Guiding Principles for Safety Inspection and Evaluation of Health Food Raw Material Strains (2020)”, the Pediococcus acidilactici Mei.1103.1 in the present application was confirmed by genome analysis to not contain common pathogenicity-related genes. These results show that the genome of the strain does not carry any known pathogenic genes, meeting the safety requirements as probiotics and food additives.

[0090] 2. Antibiotic resistance analysis of Pediococcus acidilactici Mei.1103.1

[0091] The obtained sequencing data were annotated using Prokka and RAST tools to identify all possible genes and functional regions. The genomic data were then compared with known antibiotic resistance gene databases (such as CARD and ResFinder) using BLAST tools, focusing on identifying genes associated with antibiotic resistance, including enzymes, membrane proteins, and pumps encoded by resistance genes. Furthermore, antibiotic susceptibility testing was performed to further confirm resistance. The E-test method was used to test the susceptibility of Pediococcus acidilactici Mei.1103.1 to common antibiotics, and the minimum inhibitory concentration (MIC) was recorded to determine whether the strain exhibited antibiotic resistance. Gene annotation and BLAST comparison analysis revealed no genes associated with antibiotic resistance in the genome of Pediococcus acidilactici Mei.1103.1. E-tests demonstrated sensitivity to all commonly used antibiotics, with no resistance. The analysis of this example shows that the genome of Pediococcus acidilactici Mei.1103.1 does not contain genes related to antibiotic resistance and does not show resistance to common antibiotics, thus meeting the safety requirements for use as a probiotic and food additive.

[0092] 3. Hemolytic analysis of Pediococcus acidilactici Mei.1103.1

[0093] The lactic acid bacteria Mei.1103.1 was inoculated into MRS medium and cultured for 18 h until the bacteria entered the logarithmic growth phase. The cultured lactic acid bacteria Mei.1103.1 was aseptically adjusted to an appropriate concentration (about 10 8 CFU / mL), use a sterile inoculation loop to evenly streak the bacterial solution on the surface of the blood agar plate, and place the blood agar plate in a 37°C incubator for 24-48 hours to observe whether the strain has hemolytic performance. The commercial Staphylococcus aureus ATCC 25923 (known as a β-hemolytic strain) is set as the positive control group. Hemolysis is judged by observing the hemolysis zone around the bacterial growth on the blood agar plate. According to the nature of the hemolysis zone, it can be divided into: β-hemolysis: The bacteria completely dissolve the red blood cells in the blood agar around it, which appears as a clear transparent area. α-hemolysis: The bacteria partially dissolve the red blood cells in the blood agar, forming a green or brown area. γ-hemolysis: The bacteria do not dissolve the red blood cells, and the blood agar remains intact. This example is tested by blood agar plate hemolysis test (the results are shown in the figure). Figure 6 As shown, Figure 6 A in the figure is the positive control Staphylococcus aureus. Figure 6(B in the expression "Pediococcus acidilactici" stands for "Mei.1103.1"). It was confirmed that Pediococcus acidilactici Mei.1103.1 is non-hemolytic under conventional culture conditions. This strain does not exhibit β-hemolytic or α-hemolytic characteristics, but rather γ-hemolytic characteristics, meaning it lacks the ability to lyse red blood cells. Therefore, Pediococcus acidilactici Mei.1103.1 can be identified as non-hemolytic and meets the safety requirements for probiotics in food and health products.

[0094] Example 6 Verification of the uric acid-lowering effect of Pediococcus acidilactici Mei.1103.1

[0095] 1. Animal experiments

[0096] The experimental animals used to verify the uric acid-lowering effect of Pediococcus acidilactici Mei.1103.1 in the present invention include zebrafish and rats.

[0097] Zebrafish were raised in 28°C fish farming water (water quality: 200 mg of instant sea salt was added to every 1 L of reverse osmosis water, conductivity was 450-550 uS / cm; pH was 6.5-8.5; hardness was 50-100 mg / L CaCO3). The fish were bred and provided by the Huante Company Fish Farming Center. The experimental animal license number is SYXK (Zhejiang) 2022-0004. The breeding and management complies with the requirements of the international AAALAC certification (certification number: 001458). 5 dpf wild-type AB strain zebrafish were randomly selected in 6-well plates, and 30 zebrafish were treated in each well. They were divided into 6 groups, namely control group, model group, low-dose group, medium-dose group, high-dose group, and positive drug control group. The control group was given normal saline, and the other groups were given potassium oxonate and sodium xanthine to induce hyperuricemia. In addition, the low-dose group was given 10 7 CFU of Pediococcus acidilactici Mei.1103.1, the medium dose group was given 10 8 CFU of Pediococcus acidilactici Mei.1103.1, high-dose group was given 10 9 The zebrafish were treated with CFU of Pediococcus acidilactici Mei.1103.1. The positive control group was given 136 μg / mL allopurinol at 28°C for 1 day. The Amplex® Red Uric Acid / Uricase Assay Kit was used to collect data using a multifunctional microplate reader software. The uric acid fluorescence value of zebrafish was analyzed. The statistical analysis results of this indicator were used to evaluate the uric acid-lowering efficacy of Pediococcus acidilactici.

[0098] 24 SPF level SD rats (6 weeks old, weighing about 200 g) were purchased from Beijing Sbiopharm Biotechnology Co., Ltd. with license number SYXK (Gan) 2021-0001. The rats were raised in the Animal Experiment School, and the feeding environment was maintained stable: the relative humidity was maintained at 60%-80%, the temperature was maintained at 22-25 ℃, the light and dark conditions were cycled for 12 hours each day, and the rats were free to eat and drink water, and the body weight of the rats was weighed and recorded every week.

[0099] After the SD rats were adaptively fed with ordinary standard feed and normal drinking water for one week, 24 rats were randomly divided into three groups, 8 rats in each group, and the specific grouping method is as follows: (1) control group (NC): fed with ordinary standard feed, and 1 mL of 0.5% carboxymethylcellulose sodium and 1 mL of normal saline were administered intragastrically in the morning every day; (2) model group (HUM): fed with high-fat high-fructose feed, and 1 mL of normal saline was administered intragastrically in the morning every day, and high uric acid was induced by potassium oxonate-adenine (potassium oxonate 500 mg / kg, adenine 100 mg / kg); (3) Pediococcus acidilactici group (Mei.1103.1): fed with high-fat high-fructose feed, and 1 mL of normal saline was administered intragastrically in the morning every day, and high uric acid was induced by potassium oxonate-adenine (potassium oxonate 500 mg / kg, adenine 100 mg / kg) and Pediococcus acidilactici Mei.1103.1 (10 9 CFU / d).

[0100] 2. Uric acid-lowering efficacy evaluation of Pediococcus acidilactici Mei.1103.1

[0101] The results of zebrafish experiments Figure 7 showed that administration of Pediococcus acidilactici Mei.1103.1 could significantly reduce the uric acid level in zebrafish, with a decrease of about 16-41% compared with the model group. The high-dose group had a greater decrease in uric acid level than the medium-dose and low-dose groups, indicating that Pediococcus acidilactici Mei.1103.1 had a uric acid-lowering effect in zebrafish and showed a dose-dependent effect. The results of rat experiments are shown in Figure 8 A of Figure 8 , and the serum uric acid level of the model group in A was significantly increased, indicating that a high uric acid model was successfully established. After administration of Pediococcus acidilactici Mei.1103.1, the serum uric acid concentration of the experimental group rats decreased significantly, with a decrease of 52%. Based on the results of zebrafish and rat experiments, Pediococcus acidilactici Mei.1103.1 showed a significant uric acid-lowering effect, providing a scientific basis for further development as a potential health product or adjunctive therapy drug.

[0102] 3. Pediococcus acidilactici Mei.1103.1 relieves kidney damage

[0103] In addition to serum uric acid, this experiment further assessed the rats' renal function (using serum creatinine and urea nitrogen levels as indicators of renal function). The rat kidneys were fixed with 4% paraformaldehyde for 24 hours. The samples were then paraffin-embedded, sectioned, stained with hematoxylin and eosin (HE), and mounted. The mounted sections were then examined and photographed under a 100× microscope to observe and analyze changes in the rats' renal tissue structure.

[0104] Renal function index results such as Figure 8 B and Figure 8 As shown in Figure C, serum creatinine and urea nitrogen levels in the model (HUM) group were significantly higher than those in the normal control (NC) group, suggesting that hyperuricemia leads to renal damage in rats. In contrast, serum creatinine and urea nitrogen levels in rats treated with Pediococcus acidilactici Mei.1103.1 were significantly reduced, indicating that this strain can improve renal function to a certain extent and has a significant renal protective effect.

[0105] The kidney damage was further evaluated by the appearance of the kidney and pathological section analysis. Figure 9 A and Figure 9 As shown in Figure B, the experiment found that the kidneys of rats in the hyperuricemia model group were significantly enlarged, showing significant edema and fibrosis. Pathological section analysis further revealed that the glomeruli of the model group rats showed varying degrees of atrophy and a significant reduction in volume, accompanied by an increase in the gap between the glomerulus and the renal capsule, suggesting damage to the renal tissue structure. However, the renal pathological damage in the group treated with Pediococcus acidilactici Mei.1103.1 was significantly alleviated, with relatively intact glomerular morphology, normalized gaps, and reduced fibrosis, indicating that Pediococcus acidilactici has a certain protective effect on renal damage caused by hyperuricemia.

[0106] 4. Pediococcus acidilactici Mei.1103.1 relieves fatty liver

[0107] The present invention further measured and evaluated the liver function of each group of rats (by measuring the four blood lipid levels in the serum as an indicator of liver function). At the same time, the rat livers were fixed with 4% paraformaldehyde for 24 hours, and then the samples were embedded in paraffin, sectioned, HE stained, and sealed. Finally, the sealed sections were placed under a 100× microscope for examination and photography to observe and analyze the changes in the rat liver tissue structure.

[0108] Changes in serum lipid levels such as Figure 10 As shown, Figure 10 A in the equation is the total cholesterol level. Figure 10 B in the figure is the triglyceride level. Figure 10 The C in the equation is the high-density lipoprotein level. Figure 10The D in the figure represents the level of low-density lipoprotein. The model group showed significant increases in total cholesterol, triglycerides, and high-density lipoprotein, indicating abnormal lipid metabolism. The intervention of Pediococcus acidilactici Mei.1103.1 significantly reduced these abnormal lipid levels, suggesting that the strain may have a positive effect on fat accumulation by regulating lipid metabolism. The liver of the control group appeared normal reddish-brown and had a smooth surface, without obvious pathological changes. In contrast, the liver of the model group showed typical pathological characteristics of fatty liver, mainly including a significant increase in liver volume and yellowing of color, suggesting disordered liver fat metabolism and the occurrence of fat deposition. However, Pediococcus acidilactici Mei.1103.1 can effectively improve the manifestations of these fatty livers and reduce fat deposition and volume increase in the liver. Further pathological sections ( Figure 11 ) analysis showed that Figure 11 A in the figure represents the appearance of rat liver. Figure 11 Figure B shows the results of HE staining. The liver cells in the model group exhibited significant pathological changes, including uneven cell size, blurred cell boundaries, and a large number of fat vacuoles between cells. These changes indicate that the liver has suffered significant damage during the process of fat accumulation. After intervention with Pediococcus acidilactici Mei.1103.1, these pathological changes were repaired to a certain extent. The morphology of the hepatocytes returned to a near-normal state, with cell size becoming more consistent, fat vacuoles decreasing, and cell boundaries becoming more clearly defined. This indicates that the strain has a certain liver-protective effect and can improve the structural damage caused by fatty liver.

[0109] 5. Pediococcus acidilactici Mei.1103.1 relieves inflammation

[0110] The present invention further measured the inflammatory factors in rat kidneys, using commercial ELISA kits to quantitatively analyze the pro-inflammatory factors IL-6, IL-1β, TNF-α and the anti-inflammatory factor IL-10. Figure 12 As shown, Figure 12 The A in it is interleukin-1β (IL-1β), Figure 12 B in it is interleukin-6 (IL-6), Figure 12 The C in TNF-α is tumor necrosis factor α (TNF-α). Figure 12D in the expression "D" stands for interleukin-10 (IL-10). Levels of the proinflammatory cytokines IL-6, IL-1β, and TNF-α in the model group were significantly elevated, indicating a significant inflammatory response in renal tissue. Conversely, levels of the anti-inflammatory cytokine IL-10 were significantly decreased, further demonstrating renal immune imbalance and exacerbated inflammatory status. Notably, the addition of Pediococcus acidilactici Mei.1103.1 significantly reduced kidney expression of the proinflammatory cytokines IL-6, IL-1β, and TNF-α, while IL-10 levels rebounded, suggesting that this strain possesses anti-inflammatory properties and can effectively alleviate renal inflammation. These results suggest that Pediococcus acidilactici Mei.1103.1 may mitigate renal inflammatory damage by modulating the immune response and balancing the expression of pro- and anti-inflammatory factors. By improving immune system function, this strain may provide a new therapeutic strategy for alleviating the inflammatory process in renal disease.

[0111] In summary, Pediococcus acidilactici Mei.1103.1 not only demonstrated excellent efficacy in lowering serum uric acid levels but also significantly improved renal and liver damage caused by hyperuricemia, regulated blood lipids, and alleviated inflammatory responses. Therefore, as a natural probiotic, Pediococcus acidilactici Mei.1103.1 has broad clinical application prospects, particularly in the treatment of hyperuricemia and related metabolic diseases (such as kidney damage and fatty liver), and has the potential to become a new natural health ingredient. These findings further support its feasibility as a clinical probiotic and lay a scientific foundation for its future application.

[0112] Example 7 Preparation of freeze-dried bacterial powder of Pediococcus acidilactici Mei.1103.1

[0113] A 1% inoculum of twice-activated Pediococcus acidilactici Mei.1103.1 was inoculated into MRS liquid medium and cultured at 37°C for 24 hours. The pellet was then centrifuged at 4500 rpm for 10 minutes to collect the precipitate, washed three times with sterile saline or phosphate buffer, and mixed with a lyoprotectant at a ratio of 1:1 (by mass). The pellet was then pre-frozen at -80°C for 12 hours and freeze-dried in a vacuum freeze dryer for 48 hours to produce lyophilized bacterial powder. The lyoprotectant was prepared as follows: 15 g of skim milk powder, 3 g of sodium L-ascorbate, 3 g of monosodium glutamate, and 5 g of xylo-oligosaccharides were dissolved in 100 mL of 0.9% saline and sterilized by heating in a water bath at 65°C for 30 minutes.

[0114] Example 8 Preparation of fermented dry rice flour

[0115] (1) Rice fermentation: Wash and dry late indica rice and soak it in water. The amount of water is 1.35 times of the dry weight of late indica rice. Then, the lactic acid bacteria Mei.1103.1-Mei.1103.5 selected in Example 1 are inoculated with 10 6 CFU / g, the fermentation temperature was controlled at 30 ℃, and the fermentation was sealed for 11 days.

[0116] (2) Fermented dry rice flour processing: After the late indica rice is fermented, it is processed through grinding, filtration, dough making, steaming, powder extrusion, boiling, cooling, panning, and drying to produce fermented dry rice flour. The specific process is as follows:

[0117] Milling: After the fermentation of indica rice is completed, it is ground into rice slurry through wet milling;

[0118] Filter pressing: The wet-milled rice slurry is pressed with a plate and frame filter press to filter out the water and form rice flour blocks. The moisture content of the rice flour blocks is controlled to be 45%;

[0119] Dough making: The filtered rice flour block is squeezed into a cylindrical dough with a bottom diameter of 14 cm and a height of 25 cm using a dough making machine;

[0120] Steaming dough: Steam the prepared cylindrical dough at 105°C for 80 minutes;

[0121] Extruding the dough: Pressurize the steamed dough to form noodles with a diameter of 2.0 mm.

[0122] Cooking noodles: Heat the extruded noodles in boiling water for 6 minutes;

[0123] Cooling: Take out the cooked vermicelli and place it in cold water to cool;

[0124] Roll the vermicelli into a powdered shape: Place the cooled vermicelli into a mold with a length, width and height of 25 cm × 15 cm × 5 cm and roll it into a powdered shape;

[0125] Drying: Place the cooled vermicelli in a light drying device to dry.

[0126] Comparative Example 1: Preparation of naturally fermented dry rice flour

[0127] (1) Rice fermentation: Soak the washed and dried late indica rice in water with the amount of water being 1.35 times the dry weight of the late indica rice. Control the fermentation temperature at 30 °C and seal the fermentation for 11 days.

[0128] (2) Processing of fermented dry rice noodles: After the rice is fermented, it is subjected to grinding, filter pressing, dough making, steaming, powder squeezing, powder boiling, cooling, panning, and drying to prepare fermented dry rice noodles. The specific steps are the same as those in Example 8.

[0129] The volatile flavor substance content in the fermented dry rice noodles prepared in Example 8 and Comparative Example 1, as well as the pH and lactic acid content in the fermentation broth during the fermentation process, were detected by the following method:

[0130] (1) Volatile flavor compound content determination: Solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS) was used on a DB-Wax column (30 m × 0.25 mm × 0.25 μm, Agilent). Relative quantification was performed using methyl myristate as the internal standard. The volatile flavor compound content of the fermented dry rice noodles prepared in Example 8 and Comparative Example 1 is shown in Table 5.

[0131] Table 5

[0132]

[0133] As shown in Table 5, Comparative Example 1 had the lowest alkenal content, with trans-2-decenal and 2-undecenal at only 184.68 μg / kg and 40.50 μg / kg, respectively, indicating that naturally fermented rice flour contains very low levels of alkenal flavor compounds. Among the rice flour fermented with Pediococcus acidilactici, the rice flour inoculated with Mei.1103.1 had the highest content of volatile alkenal flavor compounds, compared to the rice flour inoculated with Mei.1103.2-Mei.1103.5. The levels of trans-2-decenal and 2-undecenal were 1277.05 μg / kg and 313.47 μg / kg, respectively, indicating that inoculation with Mei.1103.1 helped increase the content of trans-2-decenal and 2-undecenal in the fermented rice flour. Trans-2-decenal and 2-undecenal, as important flavor-active compounds, can significantly enhance the flavor quality of fermented dry rice noodles. Among them, the product obtained by fermentation with Mei.1103.1 strain exhibits the most prominent flavor characteristics.

[0134] (2) Detection of pH and lactic acid during fermentation

[0135] The pH and lactic acid changes in the rice fermentation process of Example 8 and Comparative Example 1 were detected, and the results were as follows: Figure 13 、 Figure 14 As shown. Figure 13 、 Figure 14Comparative Example 1 showed the highest pH value and the lowest lactic acid content. At the end of fermentation, the pH and lactic acid content in Comparative Example 1 were 4.71 and 34.12 mmol / L, respectively, indicating that Comparative Example 1 had a weak acid production capacity. Among the rice noodles fermented with Pediococcus acidilactici, the pH value of the rice noodles inoculated with Mei.1103.1 decreased the fastest and the lactic acid content increased the fastest compared to those inoculated with Mei.1103.2-Mei.1103.5. At the end of fermentation, the pH and lactic acid content were 3.42 and 78.69 mmol / L, respectively, indicating that Mei.1103.1 had the strongest acid production capacity and was able to effectively inhibit the growth of other bacteria.

[0136] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A Pediococcus acidilactici, characterized in that The lactic acid bacteria is lactic acid bacteria ( Pediococcus acidilactici ) Mei.1103.1, the depository is the General Microbiology Center of China Culture Collection Administration, the deposit number is CGMCC NO.32564, the deposit date is November 11, 2024, and the deposit address is the Institute of Microbiology, Chinese Academy of Sciences, No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing.

2. A lactic acid bacteria agent, characterized in that The active ingredient of the lactic acid bacteria agent includes the Pediococcus acidilactici according to claim 1.

3. A freeze-dried lactic acid bacteria powder, characterized in that: The active ingredient of the freeze-dried lactic acid bacteria powder includes the Pediococcus acidilactici according to claim 1.

4. Use of the Pediococcus acidilactici according to claim 1, the lactic acid bacteria agent according to claim 2, or the lyophilized lactic acid bacteria powder according to claim 3 in the preparation of a degraded nucleoside product or an immunomodulatory product.

5. Use of the Pediococcus acidilactici according to claim 1, the lactic acid bacteria agent according to claim 2, or the lyophilized lactic acid bacteria powder according to claim 3 in the preparation of a product for lowering uric acid, preventing and / or treating hyperuricemia.

6. Use of the Pediococcus acidilactici according to claim 1, the lactic acid bacteria agent according to claim 2, or the lyophilized lactic acid bacteria powder according to claim 3 in the preparation of a product for preventing and / or treating fatty liver.

7. Use of the Pediococcus acidilactici according to claim 1, the lactic acid bacteria agent according to claim 2, or the lyophilized lactic acid bacteria powder according to claim 3 in the preparation of a product for reducing serum creatinine and / or urea nitrogen levels.

8. Use of the Pediococcus acidilactici according to claim 1, the lactic acid bacteria agent according to claim 2, or the freeze-dried lactic acid bacteria powder according to claim 3 in preparing fermented dry rice noodles, characterized in that: The application includes increasing the content of volatile flavor compounds trans-2-decenal and 2-undecenal in fermented dry rice flour, increasing the lactic acid content in the fermentation liquid and reducing the pH value of the fermentation liquid.

9. A method for preparing fermented dry rice noodles, characterized in that: The following steps are involved: S1, soaking the washed and dried late indica rice in water, wherein the amount of water added is 1.0 times to 1.5 times the dry weight of the late indica rice, and inoculating the lactic acid bacteria described in claim 1 or the lactic acid bacteria agent described in claim 2 or the lactic acid bacteria freeze-dried powder described in claim 3 for fermentation; wherein the inoculation amount of the lactic acid bacteria is 10 5 CFU / g~10 7 CFU / g, fermentation temperature is 25℃~35℃, and fermentation time is 7 days~15 days; S2, after fermentation is completed, the fermented late indica rice is subjected to grinding, filter pressing, dough making, steaming, powder squeezing, powder cooking, cooling, powder panning, and drying to make fermented dry rice noodles.

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