Pediococcus acidilactici and application thereof

Abstract

The invention discloses pediococcus acidilactici from aged shrimp paste and application of the pediococcus acidilactici. The invention specifically discloses a strain of pediococcus acidilactici ZM2025 and an application of the strain of pediococcus acidilactici ZM2025 in degradation of purine and / or improvement of hyperuricemia. The pediococcus acidilactici ZM2025 disclosed by the invention is obtained by performing multiple rounds of enrichment by using a special enrichment culture medium taking adenine, guanine, hypoxanthine and xanthine as the sole nitrogen source, and then combining with screening of a chromogenic selective culture medium and determination of a purine degradation rate. The strain has relatively strong purine degradation capability, can effectively degrade purine in food and reduce generation of uric acid, and has a remarkable effect on improving hyperuricemia and gout symptoms. The pediococcus acidilactici ZM2025 disclosed by the invention also shows good acid resistance and cholate resistance, and is suitable for being added into fermented foods or probiotic preparations as probiotics. The invention provides an important strain resource for developing a new method for treating gout on the basis of microorganisms.

Description

Technical Field

[0001] This invention belongs to the field of microbial technology and relates to a strain of Pediococcus lactis and its application, specifically to a strain of Pediococcus lactis with purine degradation ability and its application in degrading purines and / or improving hyperuricemia. Background Technology

[0002] Hyperuricemia is a common metabolic disease, mainly caused by purine metabolism disorders or impaired uric acid excretion, and is the biochemical basis of gout. Epidemiological surveys show that the global incidence of hyperuricemia is increasing year by year, reaching approximately 13.3% in the adult population of my country. Hyperuricemia not only leads to gout but is also closely related to various diseases such as hypertension, coronary heart disease, and kidney disease, becoming a significant threat to human health.

[0003] Currently, the main drugs for treating hyperuricemia include xanthine oxidase inhibitors (such as allopurinol) and drugs that promote uric acid excretion (such as benzbromarone). While these drugs have some efficacy, long-term use may lead to adverse reactions such as liver and kidney damage and skin rashes. Therefore, developing safe and effective new methods to improve hyperuricemia is of great significance.

[0004] Purines are important components of nucleotides and are widely found in various foods, such as animal organs, seafood, and legumes. Dietary purines are eventually metabolized into uric acid in the body. Therefore, limiting the intake of high-purine foods is one of the important measures for preventing and treating hyperuricemia. However, long-term strict dietary control has a significant impact on patients' quality of life.

[0005] In recent years, research has revealed that certain microorganisms possess the ability to degrade purines, offering the potential for developing novel methods to improve hyperuricemia. For example, studies have found that some lactobacilli can degrade adenine, guanine, xanthine, and hypoxanthine in culture media. However, the degradation rates for each type of purine are uneven, exhibiting substrate specificity and failing to simultaneously and rapidly degrade all types of purines, or exhibiting slow degradation rates. Furthermore, they lack tolerance to the gastrointestinal environment and food processing conditions, potentially leading to significant reductions in activity during practical applications.

[0006] Chinese patent application CN202311447010.5 discloses a fermenting Lactobacillus mucinus isolated from precipitation in Gansu Province. Its 24-hour degradation rate of adenosine is 23.06% and that of inosine is 48.72%. The degradation rate of this strain is relatively low. Further observation revealed that the degradation rate of adenosine and inosine in a short period of time was not measured, indicating that it may not be able to rapidly degrade purine substances. Purine substances in food have more time to be digested and absorbed into the body.

[0007] Chinese patent application CN202011250373.6 discloses a strain of *Lactobacillus rhamnosus* YZULr026, which exhibits an 87.85% degradation rate of guanine within 2 hours. However, its 2-hour degradation rates for xanthine and hypoxanthine are only 23.14% and 12.17%, respectively, further highlighting the substrate specificity of *Lactobacillus* for purine metabolism, indicating its inability to efficiently degrade various types of purines. Therefore, screening for novel purine-degrading bacteria with more efficient and comprehensive degradation capabilities is of great significance for improving hyperuricemia and developing low-purine foods.

[0008] Pediococcus acidilactici( Pediococcus acidilactici Pediococcus lactis is an important lactic acid bacterium widely used in dairy fermentation and holds GRAS (Generally Recognized as Safe) status. Due to its good safety and acceptability, Pediococcus lactis is an ideal probiotic and microbial carrier. Compared to most traditional lactobacilli, Pediococcus lactis typically exhibits stronger acid and salt tolerance, enabling it to survive and ferment under more demanding environmental conditions. Furthermore, Pediococcus lactis has a wider temperature adaptability, fermenting stably at both mesophilic and lower temperatures, providing greater flexibility for production processes. Secondly, the fermentation cycle of Pediococcus lactis is usually shorter, improving production efficiency. Moreover, unlike most traditional lactobacilli, Pediococcus lactis primarily produces L-lactic acid, an optical isomer that is more easily metabolized by the human body, reducing the metabolic burden that D-lactic acid may pose.

[0009] Chinese patent application CN202310041721.6 discloses a strain of Pediococcus lactis GR-5, which was used to develop and improve low-purine probiotic beer. However, further observation revealed that its degradation rates of adenine, guanine, xanthine, and xanthine within 1 hour were only 12%, 6%, 13%, and 8%, respectively.

[0010] Therefore, isolating and screening Pediococcus lactis with efficient purine degradation capabilities and applying them to improve hyperuricemia and reduce the purine content of food has important scientific significance and application value. Summary of the Invention

[0011] The purpose of this invention is to provide a strain of *Pediococcus lactis* with highly efficient purine degradation capabilities and its application in degrading purines and / or improving hyperuricemia.

[0012] To achieve the above objectives, the present invention first provides a strain of *Pediococcus lactis*, wherein the *Pediococcus lactis* is *Pediococcus lactis* (… Pediococcus acidilactici ZM2025, its accession number at the Guangdong Provincial Center for Microbial Culture Collection is GDMCC NO: 66061.

[0013] This invention also provides a method for selectively isolating the *Pediococcus lactis*, the method comprising: A) inoculating an aged shrimp paste sample into an enrichment medium with adenine, guanine, hypoxanthine, and xanthine as the sole nitrogen source, and culturing at 30°C for 24-48 hours; B) inoculating the culture from step A) into a fresh enrichment medium, repeating this step 3-4 times; C) diluting the culture from step B) and spreading it onto a selective plate containing a colorimetric indicator, and culturing at 30°C for 24-48 hours; D) picking positive colonies for colorimetric reaction, inoculating them into a assay medium containing adenine or guanine, and culturing to determine the purine degradation rate; E) selecting strains with high purine degradation rates for purification and identification to obtain the *Pediococcus lactis*.

[0014] Preferably, the content of adenine, guanine, hypoxanthine and xanthine is 0.5-1.0 g / L.

[0015] Preferably, the enrichment culture medium comprises: 10 g / L glucose, 0.5 g / L yeast extract, 1.0 g / L adenine, 0.5 g / L guanine, 1.0 g / L hypoxanthine, 0.5 g / L xanthine, 1.0 g / L K2HPO4, 0.2 g / L MgSO4·7H2O, 0.1 g / L NaCl, and a pH of 7.0-7.2.

[0016] Preferably, the colorimetric indicator is bromophenol blue.

[0017] Preferably, the purine degradation rate is determined by measuring the changes in the contents of adenine, guanine, hypoxanthine, and xanthine in the culture medium before and after culture using high performance liquid chromatography (HPLC).

[0018] The present invention also provides cultures containing the aforementioned *Pediococcus lactis*. The term "culture" refers to a liquid or solid product (all substances within the culture vessel, i.e., fermentation products) that has grown a microbial community after artificial inoculation and cultivation. That is, it is a product obtained by growing and / or amplifying microorganisms, which can be a biologically pure culture of microorganisms, or it can contain a certain amount of culture medium, metabolites, or other components produced during the cultivation process. The term "culture" also includes passaged cultures obtained by subculturing microorganisms, which can be a culture of a single generation or a mixture of several generations.

[0019] The culture involves culturing the *Pediococcus lactis* ZM2025 under conditions suitable for culturing *Pediococcus lactis*. Those skilled in the art are familiar with various methods for culturing the strains of this invention, including batch or continuous methods such as fed-batch or repeated fed-batch culturing, but the invention is not limited thereto.

[0020] The present invention also provides a microbial agent containing the aforementioned *Pediococcus lactis* and / or the aforementioned culture. Further, the microbial agent may be a microbial agent, a biological agent, a health food, a functional food, a probiotic preparation, a pharmaceutical preparation, a medicinal supplement, or a fermented food.

[0021] Furthermore, the bacterial agent can be obtained by purifying Pediococcus lactis (… Pediococcus acidilactici ZM2025 is mixed with a solid carrier and / or additives to obtain a solid microbial agent. The solid carrier includes one or more of maltodextrin, lactose, sucrose, glucose, fructose, starch, mannitol, microcrystalline cellulose, calcium carbonate, silica, and silicon dioxide; the additives include one or more of antioxidants, moisture-proofing agents, preservatives, stabilizers, and emulsifiers.

[0022] Furthermore, the bacterial agent can be obtained by introducing Pediococcus lactis (… Pediococcus acidilactici ZM2025 was inoculated into a liquid culture medium and cultured, and the bacterial solution was collected to obtain a liquid bacterial agent. Further, the bacterial agent can be obtained by centrifuging the bacterial solution, collecting the supernatant as a liquid bacterial agent, and / or by collecting the precipitate and preparing a bacterial suspension as a liquid bacterial agent.

[0023] The present invention also provides the use of the said *Pediococcus lactis* and / or the said culture and / or the said bacterial agent in degrading purines and / or improving hyperuricemia.

[0024] The present invention also provides a method for producing a fermented food containing the aforementioned *Pediococcus lactis*, the method comprising inoculating the *Pediococcus lactis* into a food ingredient and fermenting it under suitable conditions. Preferably, the food ingredient is a dairy product, soy product, grain, or fruit and vegetable.

[0025] The present invention also provides any of the following applications of the said *Pediococcus lactis* and / or the said culture and / or the said bacterial agent: A1) application in the biodegradation of purines in food, and / or preparation of formulations for the biodegradation of purines in food; A2) application in the preparation of products for improving hyperuricemia; A3) application in the preparation of health food; A4) application in the preparation of probiotic formulations; A5) application in the preparation of fermented foods with uric acid-lowering function.

[0026] The present invention also provides a method for preventing and / or improving hyperuricemia, characterized in that the method comprises orally administering the *Pediococcus lactis* and / or the culture or the bacterial agent to a subject. Preferably, the number of live bacteria administered orally is 1 × 10⁻⁶. 8 ~1×10¹ 0 cfu / day.

[0027] Compared with the prior art, the present invention has the following advantages: (1) This invention provides a method for selectively isolating Pediococcus lactis with purine degradation ability. The method involves multiple enrichment in an enrichment medium with various purines as the sole nitrogen source to enrich strains with purine degradation ability. Then, selective separation is performed using a colorimetric indicator. Finally, screening is performed by measuring the purine degradation rate. This method is simple, efficient, and highly targeted, and can effectively isolate Pediococcus lactis with high purine degradation ability.

[0028] (2) The *Pediococcus lactis* ZM2025 isolated by this invention has a high efficiency in purine degradation. The 4-hour degradation rates of adenine, guanine, hypoxanthine and xanthine are as high as 90.2%, 86.8%, 89.35% and 83.37%, respectively, which are significantly better than other reported microorganisms.

[0029] (3) The Lactococcus lactis ZM2025 of the present invention has good acid and alkali tolerance and bile salt tolerance, and can survive and function in the gastrointestinal environment. In vivo experiments have confirmed that it can significantly reduce the serum uric acid level in hyperuricemia model animals.

[0030] (4) The Lactococcus lactis ZM2025 of the present invention is a lactic acid bacterium with GRAS status, high safety, and can be widely used in food, health products, medicine and other fields, providing a new safe and effective method for improving hyperuricemia. Attached Figure Description

[0031] Figure 1 The degradation abilities of different strains of adenine, guanine, hypoxanthine and xanthine.

[0032] Figure 2 This is a plate colony morphology diagram of strain ZM2025.

[0033] Figure 3 A phylogenetic tree was constructed using the neighbor-joining method based on the 16S rDNA sequences of strain ZM2025 and related strains.

[0034] Figure 4 This is a growth curve of strain ZM2025.

[0035] Figure 5 The 4-hour degradation capacity of strain ZM2025 for adenine, guanine, hypoxanthine and xanthine is measured.

[0036] Figure 6 The tolerance of strain ZM2025 to different pH values ​​and bile salt concentrations was investigated.

[0037] Figure 7 The effect of strain ZM2025 on a mouse model of hyperuricemia. Detailed Implementation

[0038] The present invention will now be described in further detail with reference to specific embodiments. The given embodiments are merely illustrative of the invention and not intended to limit its scope. The embodiments provided below can serve as a guide for further improvements by those skilled in the art and do not constitute a limitation on the invention in any way.

[0039] Unless otherwise specified, the experimental methods used in the following examples are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0040] In this embodiment, *Pediococcus lactis* ( Pediococcus acidilactici ZM2025 was deposited on March 26, 2025, at the Guangdong Provincial Microbial Culture Collection Center (GDMCC, address: 5th Floor, Building 59, Institute of Microbiology, Guangdong Academy of Sciences, No. 100 Xianlie Middle Road, Guangzhou, Guangdong Province), with accession number GDMCC NO: 66061.

[0041] Collect shrimp paste samples aged 3 years or more, weigh 10g of the sample, add 90mL of sterile physiological saline, mix thoroughly, and prepare 10 -1 Diluent. Then take 10 mL of 10 -1 The diluted solution was inoculated into 90 mL of enrichment medium with purine as the sole nitrogen source (enrichment medium composition: glucose 10 g / L, yeast extract 0.5 g / L, adenine 1.0 g / L, guanine 0.5 g / L, hypoxanthine 1.0 g / L, xanthine 0.5 g / L, K₂HPO₄ 1.0 g / L, MgSO₄·7H₂O 0.2 g / L, NaCl 0.1 g / L, pH 7.0), and incubated at 30°C for 48 hours. 5 mL of the culture was then inoculated into 95 mL of fresh enrichment medium and incubated at 30°C for 48 hours. This enrichment culture step was repeated four times.

[0042] The final enrichment culture was serially diluted 10-fold. 100 μL of the appropriately diluted bacterial solution was spread onto a selective solid medium containing bromophenol blue (0.003%) (the composition of the solid medium was the same as the enrichment medium, with the addition of 1.5% agar and 0.003% bromophenol blue). The medium was incubated at 30°C for 48 hours.

[0043] Fifteen bacterial strains that produced a distinct yellow ring (indicating the ability to metabolize adenine and cause a decrease in pH) were selected and inoculated into enrichment medium and cultured for 48 hours. The degradation rate of various purines was determined by HPLC. Figure 1The strain with the highest degradation rate was selected and purified on MRS agar plates to obtain a pure culture, which was named ZM2025.

[0044] Strain strain ZM2025 was inoculated onto MRS plates and incubated at 30°C for 24 hours. Colony morphology was then observed. Colonies were round, smooth, milky white, with regular edges, and approximately 1.0-2.0 mm in diameter. Morphological characteristics were as follows: Figure 2 As shown.

[0045] Physiological and biochemical identification of bacterium ZM2025 was performed according to the "Handbook of Systematic Identification of Common Bacteria". The results are shown in Table 1. Table 1 Note: "+" indicates a positive reaction, and "-" indicates a negative reaction.

[0046] Based on its physiological and biochemical characteristics, this strain conforms to the typical characteristics of Pediococcus lactis.

[0047] Genomic DNA was extracted from strain ZM2025 using a bacterial genomic DNA extraction kit (Beijing Solarbio Science & Technology Co., Ltd.). PCR amplification was performed using universal bacterial primers (27F: 5'-AGAGTTTGATCCTGGCTCAG-3', 1492R: 5'-GGTTACCTTGTTACGACTT-3') with the Chinco 1×TSE101 Gold Mix. The PCR products were purified and then sequenced.

[0048] The obtained 16S rDNA sequence (approximately 1450 bp) was BLAST-aligned with the NCBI database, and the results showed that the sequence was consistent with... Pediococcus acidilactici The similarity was as high as 100%. A phylogenetic tree was constructed using MEGA software. Figure 3 Further confirmation revealed that the strain was *Pediococcus lactis*. Pediococcus acidilactici ).

[0049] Based on morphological, physiological and biochemical characteristics and 16S rDNA sequence analysis, the isolated strain was identified as *Pediococcus lactis*. Pediococcus acidilactici It was named ZM2025.

[0050] Pediococcus lactis ZM2025 was inoculated into MRS liquid medium and cultured at 30°C. OD600 values ​​were measured every 2 hours, and growth curves were plotted. Results are as follows: Figure 4 As shown, the growth curve of strain ZM2025 exhibits a typical "S" shape, with a lag phase of 0-4 hours, a logarithmic growth phase of 4-12 hours, and a stationary phase after 12 hours.

[0051] Take an appropriate amount of *Pediococcus lactis* strain ZM2025 in the logarithmic growth phase, centrifuge at 8000 r / min, 4℃ for 10 minutes, discard the supernatant, and resuspend in physiological saline to a concentration of 1×10⁻⁶. 10 CFU / mL, at a ratio of 10%, were inoculated into 100 mL of sterile adenine, guanine, hypoxanthine, and xanthine solutions with a concentration of 10 mmol / L, and incubated at 30°C for 4 hours. Samples were taken before and after incubation, and the content of adenine or guanine in the culture medium was determined by HPLC to calculate the degradation rate.

[0052] HPLC conditions: C18 column (4.6×250 mm, 5 μm), mobile phase 0.02 mol / L KH2PO4 solution (pH 3.0): methanol = 90:10 (v / v), flow rate 1.0 mL / min, column temperature 30℃, detection wavelength 260 nm, injection volume 20 μL.

[0053] The control group used culture medium without inoculated strains, and was cultured and measured under the same conditions.

[0054] Purine degradation rate (%) = (Purine content in control group - Purine content in experimental group) / Purine content in control group × 100% The results are as follows Figure 5 As shown, strain ZM2025 exhibited degradation rates of 90.2%, 86.8%, 89.35%, and 83.37% for adenine, guanine, hypoxanthine, and xanthine, respectively, which are significantly higher than those of other reported microbial strains.

[0055] To assess the survival ability of strain ZM2025 in the gastrointestinal environment, its tolerance to different pH values ​​and bile salt concentrations was determined.

[0056] Acid tolerance test: A bacterial suspension of strain ZM2025 (approximately 1×10⁻⁶) was prepared. 9 The cfu / mL of the bacteria was inoculated into PBS buffer at different pH values ​​(2.0, 3.0, 4.0, 5.0, 6.0), incubated at 30°C for 3 hours, and the number of surviving bacteria was determined by plate counting.

[0057] Bile salt tolerance test: A bacterial suspension of strain ZM2025 (approximately 1×10⁻⁶) was prepared. 9 CFU / mL was inoculated into MRS medium containing different concentrations of bile salts (0%, 0.1%, 0.3%, 0.5%, 1.0%) and incubated at 30°C for 24 hours. The number of surviving bacteria was then determined by plate counting.

[0058] The results are as follows Figure 6As shown, strain ZM2025 exhibited good survival rates in environments above pH 3.0, and after incubation for 3 hours at pH 4.0, the survival rate remained above 87.31%. At a bile salt concentration of 0.3%, the strain maintained a survival rate of over 89.65%. This indicates that the strain possesses good acid-base tolerance and bile salt tolerance, enabling it to survive in the gastrointestinal environment, which is of great significance for its function as an oral probiotic.

[0059] A hyperuricemia model was established: Six-week-old male ICR mice, weighing 20-25g, were randomly divided into 5 groups, with 10 mice in each group. The groups included a normal control group (NC), a model control group (MC), a positive control group (PC, allopurinol 20 mg / kg / d), and a low-dose experimental group (LD, ZM2025 bacterial suspension 1×10⁻⁶). 8 cfu / d) and high-dose experimental group (HD, ZM2025 bacterial suspension 1×10 10 (cfu / d). Except for the normal control group, mice in other groups were given intraperitoneal injections of sodium hypoxanthine (300 mg / kg) and adenosine (200 mg / kg) to establish a hyperuricemia model.

[0060] Administration method: The normal control group and the model control group were given an equal volume of physiological saline. The positive control group was given allopurinol (20 mg / kg / d) by gavage. The low-dose experimental group and the high-dose experimental group were given ZM2025 bacterial suspension (1×10⁻⁶) by gavage. 8 cfu / d and 1×10 10 (cfu / day). Administer continuously for 14 days.

[0061] Sampling and measurement: 14 days after administration, orbital venous blood was collected from mice, serum was separated, and serum uric acid (UA) content was measured using a Mindray BS-240VET fully automated biochemical analyzer. Xanthine oxidase activity and inflammatory factor (IL-1β, TNF-α) levels were measured using an ELISA kit.

[0062] The results are as follows Figure 7 As shown in the figure. Compared with the normal control group, the serum uric acid level of mice in the model control group was significantly increased (P<0.01), xanthine oxidase activity was significantly enhanced (P<0.01), and the level of inflammatory factors was significantly increased (P<0.01). Compared with the model control group, the serum uric acid level of mice in the positive control group and the experimental group was significantly decreased (P<0.01), xanthine oxidase activity was significantly decreased (P<0.01), and the level of inflammatory factors was significantly decreased (P<0.01). The high-dose experimental group showed better results than the low-dose experimental group and was close to that of the positive control group.

[0063] The results showed that Porphyromonas lactis ZM2025 could significantly reduce serum uric acid levels in hyperuricemia model mice, inhibit xanthine oxidase activity, and reduce inflammatory response, thus having a significant effect on improving hyperuricemia.

[0064] Strain ZM2025 was inoculated into high-purine foods (yeast extract, broth, shrimp paste) at an initial inoculation density of 1×10⁻⁶. 8 cfu / g or 1×10 8 After fermentation at 30℃ for 24 hours with cfu / mL, the change in purine content in the food was determined by HPLC.

[0065] Purine reduction rate (%) = (Purine content before fermentation - Purine content after fermentation) / Purine content before fermentation × 100% The results are shown in Table 2: Table 2 The results showed that strain ZM2025 could significantly reduce the purine content in food, with reduction rates of 74.0%, 66.6%, and 64.6% in yeast extract, meat broth, and shrimp paste, respectively. This provides new possibilities for the development of low-purine foods.

[0066] Strain ZM2025 was inoculated into skim milk at an initial inoculum size of 1×10⁻⁶. 8 Fermented dairy products were prepared by fermenting at 30°C for 24 hours with cfu / mL concentration.

[0067] Sensory evaluation: The color is uniform, the texture is delicate, the clots are intact, the taste is moderately sweet and sour, with the typical flavor of lactic acid bacteria fermentation, and there is no off-odor.

[0068] Physicochemical properties: pH 4.3-4.5, titratable acidity 0.8-0.9%, viscosity 3500-4000 mPa·s.

[0069] Microbiological indicators: Pediococcus lactis count ≥1×10 9 cfu / mL, coliform bacteria <3 MPN / g, yeast and mold <10 CFU / g, pathogenic bacteria not detected.

[0070] Purine content: Compared with the control group without inoculation with strain ZM2025, the purine content in fermented dairy products was reduced by 62.5%.

[0071] The results showed that strain ZM2025 can be used to prepare fermented dairy products with good sensory quality and low purine content, making it suitable for patients with hyperuricemia.

[0072] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A strain of *Pediococcus lactis*, characterized in that, The lactic acid cocci are *Pediococcus lactis* ( Pediococcus acidilactici ZM2025, with accession number GDMCC NO: 66061 at the Guangdong Provincial Center for Microbial Culture Collection, was deposited on March 26, 2025. The deposit address is 5th Floor, Building 59, Institute of Microbiology, Guangdong Academy of Sciences, No. 100 Xianlie Middle Road, Guangzhou, Guangdong Province.

2. A method for selectively isolating Pediococcus lactis, characterized in that, The method includes: A) Inoculating aged shrimp paste samples into an enrichment medium with purines (adenine, guanine, hypoxanthine, and xanthine) as the sole nitrogen source and culturing at 30°C for 24-48 hours; B) Inoculating the culture from step A) into fresh enrichment medium and repeating this step 3-4 times; C) Diluting the culture from step B) and spreading it onto a selective plate containing a colorimetric indicator, and culturing at 30°C for 24-48 hours; D) Picking colorimetrically positive colonies and inoculating them into a assay medium containing purines (adenine, guanine, hypoxanthine, and xanthine) and culturing to determine the purine degradation rate; E) Selecting strains with high purine degradation rates for purification and identification to obtain the *Pediococcus lactis*.

3. The method according to claim 2, characterized in that, The purine content is 0.5-3.0 g / L.

4. The method according to claim 2, characterized in that, The enrichment medium consisted of: 10 g / L glucose, 0.5 g / L yeast extract, 1.0 g / L adenine, 0.5 g / L guanine, 1.0 g / L hypoxanthine, 0.5 g / L xanthine, 1.0 g / L K₂HPO₄, 0.2 g / L MgSO₄·7H₂O, 0.1 g / L NaCl, and a pH of 7.0-7.

2.

5. The method according to claim 2, characterized in that, The colorimetric indicator is bromophenol blue.

6. The method according to claim 2, characterized in that, The purine degradation rate was determined by measuring the change in purine content in the culture medium before and after culture using high performance liquid chromatography (HPLC).

7. A culture containing the *Pediococcus lactis* of claim 1.

8. A bacterial agent containing the *Pediococcus lactis* of claim 1 and / or the culture of claim 7.

9. The use of the *Pediococcus lactis* of claim 1 and / or the culture of claim 7 and / or the bacterial agent of claim 8 in the degradation of purines and / or improvement of hyperuricemia.

10. A method for producing a fermented food containing the *Pediococcus lactis* of claim 1, characterized in that, The method includes inoculating the Pediococcus lactis of claim 1 into food raw materials and fermenting them under suitable conditions.

11. The method according to claim 10, characterized in that, The food ingredients are dairy products, soy products, animal products, grains, or fruits and vegetables.

12. Any of the following applications of the *Pediococcus lactis* of claim 1 and / or the culture of claim 7 and / or the microbial agent of claim 8: A1) application in the biodegradation of purines in food, and / or in the preparation of preparations for the biodegradation of purines in food; A2) application in the preparation of products for improving hyperuricemia; A3) application in the preparation of health foods; A4) application in the preparation of probiotic preparations; A5) application in the preparation of fermented foods with uric acid-lowering functions.

13. A method for preventing and / or improving hyperuricemia, characterized in that, The method comprises orally administering to the subject the *Pediococcus lactis* of claim 1 and / or the culture of claim 7 or the bacterial agent of claim 8.

14. The method according to claim 13, characterized in that, The number of live bacteria administered orally was 1×10⁻⁶. 8 ~1×10¹ 0 cfu / day.

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