Mycobacterium fermentans for producing extracellular polysaccharide and application thereof

Abstract

The application discloses a high-yield extracellular polysaccharide fermenting Myxococcus and application thereof, the high-yield extracellular polysaccharide fermenting Myxococcus is preserved in China typical culture preservation center on July 4, 2025, and the preservation number is CCTCC M 20251537, and the preservation address is: China. Wuhan. Wuhan University. The high-yield extracellular polysaccharide fermenting Myxococcus has strong resistance to strong acidic environment and high-concentration bile salt, and high-yield extracellular polysaccharide. Animal test results show that the strain and the extracellular polysaccharide produced by the strain have good blood lipid-lowering and anti-inflammatory effects.

Description

Technical Field

[0001] This invention belongs to the field of microbial technology, specifically relating to a strain of myxobacterium that produces high levels of extracellular polysaccharides for fermentation and its applications. Background Technology

[0002] Cardiovascular disease causes approximately 4 million deaths annually in China, accounting for over 46% of all deaths nationwide. This number exceeds the combined death toll from all cancers, making it the leading cause of death in my country (Hu Shengshou, 2023). Dyslipidemia is the most dangerous risk factor, including high triglycerides, high cholesterol, or a combination of both (i.e., mixed hyperlipidemia). According to the "China Cardiovascular Health and Disease Report 2024," the rate of dyslipidemia in the adult population of my country is as high as 40.4%, affecting over 400 million people. This disease is often associated with chronic diseases such as hypertension and diabetes, seriously threatening the health and lives of the Chinese population. Furthermore, numerous studies have shown that dyslipidemia is often accompanied by a chronic low-grade inflammatory state and is related to obesity and other metabolic disorders. Medical expenditures due to hyperlipidemia in my country continue to rise annually, placing a heavy economic burden on society and families. Clinically, statins are commonly used to inhibit cholesterol production, while fibrates are used to activate peroxisome proliferator-activated receptors, promoting fatty acid β-oxidation and reducing triglyceride production. However, long-term use of such medications can easily cause gastrointestinal discomfort (such as nausea, diarrhea, and bloating), rhabdomyolysis, and abnormal liver and kidney function, posing certain safety risks and making long-term use unsuitable. Therefore, there is an urgent need to find new and safer alternatives for the prevention and treatment of hyperlipidemia.

[0003] In recent years, studies have shown a close relationship between gut microbiota and hyperlipidemia. Supplementation with appropriate lactic acid bacteria (LAB) or fecal microbiota transplantation (FMT) can alleviate lipid metabolism disorders and lower blood lipid levels in patients. However, FMT technology has faced considerable resistance in its promotion, mainly due to unstable efficacy, psychological resistance from test subjects, and the possibility that donors may carry potential pathogens. LAB, on the other hand, is the most common and predominant type of beneficial bacteria in the gut microbiota. It is highly safe and also has functions such as improving non-specific immunity, regulating gut health, lowering serum cholesterol, inhibiting the growth of harmful bacteria, anti-cancer, anti-tumor, anti-diabetic, and uric acid-lowering effects. It is currently the probiotic species most closely related to human health. At present, there are no probiotic products in my country's probiotic market with clear functional claims for lowering blood lipids. Research on probiotics for lowering blood lipids has mostly focused on the isolation and screening of probiotic strains that lower cholesterol or triglycerides in vitro and on the study of their blood lipid-lowering function in animals. Very few strains have actually entered clinical trials. After probiotics such as lactic acid bacteria and bifidobacteria enter the digestive tract, they can alter the intestinal flora through competitive occupation and the production of organic acids. The interaction mechanism is very complex, and their in vivo lipid-lowering mechanism may not be consistent with their in vitro cholesterol-lowering and triglyceride-lowering effects.

[0004] Currently, the material basis for the lipid-lowering effect of lactic acid bacteria is not clearly understood, and there are few studies on screening lipid-lowering probiotic strains based on this material basis. Numerous studies have shown that the extracellular polysaccharides (EPS) of lactic acid bacteria or bifidobacteria have functions similar to those of the strains themselves. For example, lactic acid bacteria EPS have antioxidant effects, improve gut microbiota, enhance non-specific immunity, and have anti-diabetic, anti-tumor, lipid-lowering, and anti-obesity effects. However, the yield and structural composition of EPS produced by different lactic acid bacteria strains vary, and most related studies focus on the antioxidant properties of strain EPS and its fermented foods, as well as its role in thickening natural foods. There are few studies on the relationship between the yield or structural composition of lactic acid bacteria EPS and the probiotic characteristics or functional strength of the strains, and even fewer studies focus on screening high-extrapolysaccharide-producing strains and investigating their lipid-lowering functions. Therefore, screening high-extrapolysaccharide-producing lactic acid bacteria strains from the natural environment and studying their lipid-lowering functions is crucial and could provide a new direction for the screening of lipid-lowering probiotics. Summary of the Invention

[0005] The purpose of this invention is to provide a strain of *Myxobacterium* that produces high levels of extracellular polysaccharides and its applications, addressing the shortcomings of existing technologies.

[0006] The technical solution of the present invention is as follows: A high-yield extracellular polysaccharide-producing fermenting *Limosilactobacillus fermentum*, named *Limosilactobacillus fermentum* P6-1, was deposited on July 4, 2025, at the China Center for Type Culture Collection (CCTCC) with accession number CCTCC M 20251537, located at Wuhan University, Wuhan, China.

[0007] The microbial agent for fermenting Lactobacillus mucinus.

[0008] Furthermore, the microbial agent is a bacterial suspension or fermentation broth of fermented Lactobacillus mucinus.

[0009] The application of the fermented Lactobacillus mucilaginosus or its microbial agent in the production of extracellular polysaccharides.

[0010] An extracellular polysaccharide, said extracellular polysaccharide being obtained by fermentation of *Lactobacillus mucilaginosus* or its microbial inoculum.

[0011] The application of the fermented Lactobacillus mucinus or its microbial agent in the preparation of lipid-lowering drugs, health products or food.

[0012] The application of the fermented Lactobacillus mucinus or its microbial agent in the preparation of anti-inflammatory drugs, health products or food.

[0013] The application of the extracellular polysaccharide in the preparation of lipid-lowering drugs, health products or food.

[0014] The application of the extracellular polysaccharide in the preparation of anti-inflammatory drugs, health products or food.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention obtained a strain of fermenting *Lactobacillus mucinus* P6-1 (… Limosilactobacillus fermentum P6-1), deposited at the China Center for Type Culture Collection (CCTCC), accession number CCTCC M20251537, deposited on July 4, 2025; deposit address: Wuhan University, Wuhan, China.

[0016] 2. Animal experiments showed that the fermented Lactobacillus mucinus P6-1 obtained in this invention can significantly reduce serum and liver TG, TC and LDL-C levels, and significantly reduce hepatic cell fat accumulation and steatosis.

[0017] 3. Animal experiments have shown that the fermented Lactobacillus mucosa P6-1 obtained in this invention significantly alleviates systemic and local intestinal inflammatory responses associated with a high-fat diet by downregulating pro-inflammatory factors such as TNF-α, IL-6, and IL-1β, improving colonic mucosal structure, and reducing inflammatory cell infiltration, thus demonstrating a clear anti-inflammatory effect.

[0018] 4. The fermented Lactobacillus mucinus P6-1 of the present invention has strong resistance to strongly acidic environments and high concentrations of bile salts, thus ensuring a sufficient survival rate after passing through the gastrointestinal tract and better exerting its efficacy.

[0019] 5. The present invention provides a strain of fermenting Lactobacillus fermentum P6-1 that produces high levels of extracellular polysaccharides. Animal experiments have shown that the extracellular polysaccharides produced by this strain have excellent lipid-lowering and anti-inflammatory effects. Attached Figure Description

[0020] Figure 1 The images show colony and cell images of strain P6-1, where A is a colony image of strain P6-1 and B is a cell image of strain P6-1.

[0021] Figure 2 The graph shows the results of four serum lipid tests in mice, where ** indicates a significant difference compared to the HFD group. p <0.05); *** and **** represent extremely significant differences compared to the HFD group ( p <0.01).

[0022] Figure 3 This is a graph showing the results of four lipid profile tests in mouse liver. ** indicates a significant difference compared to the HFD group. p<0.05); *** and **** represent extremely significant differences compared to the HFD group ( p <0.01).

[0023] Figure 4 Image showing the results of Oil Red O staining of liver sections.

[0024] Figure 5 Image showing the results of HE staining of liver sections.

[0025] Figure 6 This is a graph showing the results of serum three pro-inflammatory factors. ** indicates a significant difference compared to the HFD group. p <0.05); *** and **** represent extremely significant differences compared to the HFD group ( p <0.01).

[0026] Figure 7 Image showing the HE staining results of mouse colon sections. Detailed Implementation

[0027] The present invention will be further described below with reference to specific embodiments, but this does not limit the scope of protection and application of the present invention: I. Screening and Identification of Limosilactobacillus fermentum P6-1 Example 1 Screening of strains 1. Sample Source The strain provided by this invention was isolated from homemade pickled vegetable juice made by farmers in a village in Guiyang City, Guizhou Province, and the pickled vegetables were not mixed with any special starter culture or additives.

[0028] 2. Separation and purification Take 1 mL of kimchi juice sample and mix thoroughly with 9 mL of sterile physiological saline. Then, take 1 mL of the mixture for serial dilution. Spread 200 μL of the diluted solution evenly onto an MRS plate containing 0.3% calcium carbonate (10.0 g peptone, 10 g yeast extract, 1.0 mL Tween 80, 5 g beef extract, 2.0 g diammonium citrate, 3.5 g sodium acetate, 2.0 g dipotassium hydrogen phosphate, 0.58 g magnesium sulfate, 20.0 g sucrose, 0.25 g manganese sulfate, 15 g agar, 3 g calcium carbonate, 1000 mL distilled water, pH 6.6), and place the plate in an anaerobic incubator (with anaerobic gas-generating bag for deoxygenation) and incubate at 37°C for 48 h. After the culture is completed, select large, milky white, moist and smooth, high and rounded colonies with neat edges from each group of plates. Repeat the streak purification culture 1 to 3 times until the colony morphology is uniform. Take a single colony and transfer it to an MRS slant for overnight culture. Store the slant at 2 to 6 ℃ for later use.

[0029] 3. Strains screening Take the purified plate samples and pick single colonies with a sterile toothpick. Select strains with a colony length greater than 10 mm for secondary screening. Take the seed culture from the initial screening slant and transfer it to MRS liquid medium. Incubate overnight at 37°C. Take 2% of the liquid seed culture and transfer it to 100 mL of MRS liquid medium. Incubate at 37°C for 24 h to prepare the fermentation broth. Centrifuge the fermentation broth at 12000 rpm for 10 min to separate the supernatant and cell pellet. Wash the cell pellet three times with physiological saline, treat it in a boiling water bath for 10 min (to inactivate polysaccharide hydrolase), cool it, and resuspend it in 1 / 2 volume of 10 mM phosphate buffer (pH=6.7, containing 20 μg / mL lysozyme). Incubate at 37°C and 140 rpm for 1 h with constant temperature shaking, then vortex for 15 min. Centrifuge at 12000 rpm for 10 min and take the supernatant to prepare the cell lysis lysate. The fermentation supernatant and cell lysis supernatant prepared above were added to 4% (m / v) trichloroacetic acid (to precipitate proteins), mixed by inversion, and incubated overnight at 2-6℃. The mixture was then centrifuged at 12000 rpm for 20 min, and the supernatant was collected. 80% (v / v) ethanol solution was added to the supernatant (to precipitate polysaccharides), mixed by inversion, and incubated overnight at 2-6℃. The mixture was then centrifuged at 12000 rpm for 20 min, and the supernatant was discarded. The precipitate was dissolved in an equal volume of distilled water to prepare crude samples of fermentation supernatant polysaccharide (SPS) and fermentation broth cell capsule polysaccharide (CPS). The polysaccharide content was determined using the phenol-sulfuric acid method, and the SPS and CPS yields of each strain were calculated.

[0030] As a result, a high-yielding lactic acid bacteria strain was screened. Its fermentation broth after 24 h of culture was abnormally viscous (indicating high polysaccharide production). The yields of SPS and CPS polysaccharides were 1475.42 µg / mL and 24.53 µg / mL, respectively. Compared with other known strains grown under unoptimized culture media and fermentation conditions, this strain exhibited higher EPS yields and possesses significant research and application value. This strain was named P6-1.

[0031] Example 2 Identification of the strain 1. Morphological identification Dilute the P6-1 culture medium and spread it on a plate. Incubate at 37°C upside down for 48 h. Observe the colony characteristics on plates with colony counts between 30 and 300. Pick single P6-1 colonies for Gram staining, and examine the prepared thin sections under an oil immersion microscope.

[0032] The results are as follows Figure 1As shown: P6-1 colonies are significantly larger than other isolated strains. The colonies are milky white, round, smooth, and have a distinct frankincense aroma. They also have a strong acid-producing ability and can form a large calcium carbonate hydrolysis zone after 48 hours. The colonies are viscous. The cells are stained purple and are single or double rod-shaped with an aspect ratio of about 2 to 3.

[0033] 2. Identification of physiological and biochemical characteristics Starting with strain P6-1, perform tests such as catalase test, glucose gas production test, litmus milk test, nitrate reduction test, gelatin liquefaction test, indole test, hydrogen sulfide test, starch hydrolysis test, and VP test. For specific procedures, refer to the "Manual of Systematic Identification of Common Bacteria" and "Bergey's Manual of Bacterial Identification" (8th edition).

[0034] The results of the identification are as follows: Note: + indicates positive; - indicates negative. 3. 16S rDNA identification Using a single P6-1 colony isolated by streak plating as a template, and universal bacterial primers 27F and 1492R as primers, a certain amount of 2×Taq PCR mix was added for 16S rDNA PCR amplification. The reaction conditions were: 98℃ for 5 min; 94℃ for 30 s, 55℃ for 30 s, 72℃ for 90 s; 72℃ for 5 min, for 30 cycles. After verification by agarose gel electrophoresis, the PCR product was sent to Shanghai Sangon Biotech Co., Ltd. for sequence analysis. The determined 16S rDNA sequence was BLAST-aligned in GenBank (http: / / www.ncbi.nlm.nih.gov / blast / ). The alignment showed that the sequence had 99.90% homology with Limosilactobacillus fermentumstrain IMAU32180.

[0035] Based on morphological, physiological and biochemical characteristics and molecular identification results, strain P6-1 was identified as *Limosilactobacillus fermentum*, with accession number CCTCC NO: M 20251537; it was deposited at the China Center for Type Culture Collection (address: Wuhan University, Wuhan, China) on July 4, 2025, and named *Limosilactobacillus fermentum* P6-1.

[0036] II. Tolerance Test Example 3: Tolerance test of fermenting Lactobacillus mucinus P6-1 1. Acid resistance test Activated 5% liquid seed culture was transferred to liquid MRS medium at pH 2.0 and incubated at 37°C. Culture media at 0, 2, 4, and 6 h were serially diluted, and 200 μL of each dilution was plated onto MRS plates and incubated at 37°C for 48 h. Colony counts were recorded, and survival rates were calculated. Results are shown in Table 2. 2. Bile salt tolerance test Activated 5% liquid seed culture was transferred to MRS liquid medium containing 0.3% porcine bile salts and incubated at 37°C. Culture media at 0, 2, 4, and 6 h were serially diluted, and 200 μL of each dilution was plated onto MRS plates and incubated at 37°C for 48 h. Colony counts were recorded, and survival rates were calculated. Results are shown in Table 3. The above experimental results indicate that *Lactobacillus fermentum* P6-1 exhibits strong resistance to both highly acidic environments and high concentrations of bile salts. Even after 6 hours of treatment, a high percentage of bacteria remained viable, particularly demonstrating strong tolerance to bile salts. The number of viable bacteria after 6 hours of treatment was higher than that after 4 hours, showing an increasing trend. Good tolerance to strong acids and bile salts is a prerequisite for ensuring sufficient survival of lactic acid bacteria after passing through the gastrointestinal tract, which is beneficial for maximizing the efficacy of probiotics.

[0037] III. Animal Experiments Example 4 Animal experiment on fermentation of Lactobacillus mucinus P6-1 1. Experimental Methods Preparation of bacterial suspension: *Lactobacillus fermentans* P6-1, frozen at -80℃, was streaked onto MRS solid medium and incubated at 37℃ for 48 h. Single colonies were picked and streaked twice more. Single colonies were then picked and inoculated onto MRS slant medium and incubated overnight at 37℃. The slant culture was then inoculated onto MRS liquid medium and incubated overnight at 37℃. A 2% inoculum was then added to MRS liquid medium and incubated at 37℃ for 12 h. The fermentation broth of *Lactobacillus fermentans* P6-1 was centrifuged at 12000 rpm for 10 min to separate the supernatant and bacterial cells. The supernatant was reserved for use. The bacterial cells were washed three times with pH 7.0 PBS solution to prepare a viable bacterial concentration of 1.0 × 10⁻⁶. 10 CFU / mL bacterial suspension.

[0038] Preparation of extracellular polysaccharides: Take the fermentation supernatant of P6-1 above and prepare extracellular polysaccharide samples according to the method in Example 1. Dissolve the polysaccharide precipitate after alcohol precipitation in an appropriate amount of purified water to prepare a 25 g / L EPS solution.

[0039] Forty male adult Kunming mice at about 8 weeks of age (the experimental animals were purchased from Spf (Beijing) Biotechnology Co., Ltd., and the experimental animal production license number: SCXK (Beijing) 2024-0001) were adaptively fed for one week and then randomly divided into 4 groups (n = 10).

[0040] Normal diet control group (ND): Fed with normal maintenance diet and gavaged with 100 μL / rat / d of PBS; High-fat model group (HFD): Fed with high-fat diet (the diet formula was: 15.0% sucrose, 15% lard, 0.3% cholesterol, 69.7% basal diet, purchased from Jiangsu Xietong Pharmaceutical Biotechnology Co., Ltd.) and gavaged with 100 μL / rat / d of PBS; Live bacteria P6-1 intervention group (P6-1): Fed with high-fat diet and gavaged with P6-1 live bacteria suspension (daily dose: 1×10 9 CFU / rat); P6-1 exopolysaccharide intervention group (P6-1EPS): Fed with high-fat diet and gavaged with P6-1 EPS (daily dose: 100 μL / rat / d).

[0041] During this period, the mice were allowed to eat and drink freely for 7 weeks. The animals were housed in the animal laboratory of the School of Life Sciences, Guizhou Normal University, at a temperature of 20-26°C, a humidity of 40%-70%, and a light-dark cycle of 12 h / 12 h.

[0042] After the feeding experiment was completed, blood was taken from the inner canthus of the eyes of the animals in each group, and the serum was separated by centrifugation. The four serum lipids (TG, TC, LDL-C, and high-density lipoprotein cholesterol (HDL-C)) and pro-inflammatory factors (IL-|β, IL-6, TNF-α, and LPS) were detected using an ELISA kit. The livers of the mice were taken, and a part of them was homogenized. The levels of TG, TC, LDL-C, and HDL-C in the liver homogenate were detected using a kit. Another part of the liver tissue was stained with Oil Red O and hematoxylin (HE) respectively to prepare sections, and the liver fat accumulation and degeneration were observed. The colon tissues were taken to prepare sections, and the degree of colon inflammation or lesions was observed by HE staining. The serum, liver, and colon tissue samples were sampled under the guidance of technicians from Wuhan Servicebio Technology Co., Ltd., and the company was entrusted to conduct detection and slide preparation analysis.

[0043] 2. Experimental results The detection results of the four serum lipids are as Figure 2As shown, compared with the ND group, the HFD group mice had significantly higher serum TC, TG, and LDL-C levels (p<0.05), indicating that a high-fat diet can induce elevated serum lipids in mice. Compared with the HFD group mice, the P6-1 group and P6-1EPS group mice had extremely significantly lower serum TC, TG, and LDL-C levels (p<0.01), with serum TG levels in the two groups being only 1.14 mmol / L and 1.49 mmol / L, respectively, approximately 32.4% and 42.3% of the HFD group, and 39.7% and 51.9% of the ND group. These data indicate that both P6-1 bacterial suspension and P6-1 EPS significantly inhibited the increase in TC, TG, and LDL-C induced by a high-fat diet (p<0.01), and their efficacy in reducing serum TG was particularly significant.

[0044] Liver lipid profile results as follows Figure 3 As shown, compared with the ND group, the HFD group mice had significantly higher serum TC, TG, and LDL-C levels (p<0.05), indicating that a high-fat diet can induce elevated liver lipids in mice. Compared with the HFD group mice, the P6-1 group and P6-1EPS group mice had significantly lower liver TC, TG, and LDL-C levels (p<0.05), indicating that both P6-1 bacterial suspension and P6-1 EPS significantly inhibited the increase in liver TC, TG, and LDL-C induced by a high-fat diet (p<0.05). However, they also reduced the level of liver HDL-C, and the characteristics of their effects differed from those on the four serum lipid parameters, especially the weaker effect on TG. This may be due to the different mechanisms by which HDL-C and LDL-C transport cholesterol; HDL-C is mainly responsible for transporting cholesterol from serum to the liver, while LDL-C is responsible for transporting cholesterol from the liver to the serum.

[0045] Oil Red O staining results of liver tissue are as follows Figure 4 As shown, the HFD group exhibited numerous red lipid droplets in hepatocytes (green arrows), resulting in a distinctly red liver tissue. The ND group showed fewer tiny red lipid droplets in hepatocytes, leading to a deeper blue color in the liver tissue. The P6-1 and P6-1EPS groups showed lipid accumulation in hepatocytes that fell between the ND and HFD groups (green arrows), and the section color also fell between the two groups. This indicates that both the P6-1 bacterial suspension and P6-1 EPS can inhibit HFD-induced lipid accumulation in hepatocytes.

[0046] Results of HE staining of liver tissue as follows Figure 5As shown, in the HFD group, numerous hepatocytes with steatosis were observed around the central vein and portal areas of the liver, as well as within the parenchyma (green arrows, white round cells). Small, round vacuoles were visible in the cytoplasm, along with mild edema in a few hepatocytes (yellow arrows). The cytoplasm was loose and lightly stained, and extensive vascular congestion was observed (orange arrows). In contrast, only a very small number of hepatocytes with steatosis were observed around the central vein and portal areas of the liver, as well as within the parenchyma (green arrows). In the P6-1 group, a small number of hepatocytes with steatosis were observed around the central vein and portal areas of the liver, as well as within the parenchyma (green arrows). Small, round vacuoles were visible in the cytoplasm, along with numerous sinusoids and extensive vascular congestion (orange arrows). This indicates that both P6-1 bacterial suspension and P6-1 EPS can inhibit HFD-induced hepatocyte steatosis.

[0047] In conclusion, both P6-1 bacterial suspension and P6-1 EPS can significantly reduce serum and liver TG, TC and LDL-C levels, and significantly reduce hepatic cell fat accumulation and steatosis.

[0048] Serum pro-inflammatory factor test results as follows Figure 6 As shown in the figure. Compared with the high-fat HFD group, the serum levels of pro-inflammatory factors TNF-α, IL-6, and IL-1β in the P6-1 intervention group were all significantly decreased (p < 0.01); in the P6-1EPS group, only IL-6 and IL-1β were significantly decreased (p < 0.01), while the TNF-α level showed no significant difference (p > 0.05). This indicates that both P6-1 and its EPS can effectively inhibit the systemic inflammatory response induced by a high-fat diet, but their characteristics of action are different. To observe local intestinal inflammation and changes in mucosal barrier structure, HE staining was performed on the colon tissue of experimental mice, and the results are shown in the figure. Figure 7 As shown in the figure. Histological observation results showed that the mucosal epithelial structure of the ND control group was intact, with a large number of intestinal glands in the lamina propria, which were short and tubular, densely arranged, with abundant goblet cells, and occasional necrosis of intestinal gland epithelial cells (yellow arrows). No obvious inflammatory cell infiltration was observed in the mucosa and submucosa. In the high-fat HFD group, focal erosions were observed, with a small number of mucosal epithelial cells and intestinal gland epithelial cells sloughed off (brown arrows), occasional necrotic cell fragments (yellow arrows), a small amount of intestinal gland structure loss, and a very small amount of connective tissue hyperplasia (blue arrows); occasional focal aggregation of lymphocytes was observed (green arrows), showing obvious inflammatory changes and mucosal barrier damage. In the P6-1 and its EPS intervention groups, the colonic mucosal epithelial structure was intact, with a large number of intestinal glands in the lamina propria, which were short and tubular, densely arranged, with abundant goblet cells, and occasional focal aggregation of lymphocytes (green arrows). The colonic tissue structure destruction and inflammatory changes caused by the high-fat diet were significantly improved.

[0049] Based on the combined results of serum pro-inflammatory factor detection and colon HE staining, it can be concluded that *Lactobacillus mucosa* P6-1 significantly alleviates systemic and local intestinal inflammatory responses associated with a high-fat diet by downregulating pro-inflammatory factors such as TNF-α, IL-6, and IL-1β, improving colonic mucosal structure, and reducing inflammatory cell infiltration. This demonstrates a clear anti-inflammatory effect and provides experimental evidence for its use as an adjunct intervention for chronic low-grade inflammation associated with a high-fat diet.

Claims

1. A strain of *Lactobacillus* that produces high levels of extracellular polysaccharides through fermentation, characterized in that... The high-yield extracellular polysaccharide-producing fermenting *Limosilactobacillus fermentum* was named *Limosilactobacillus fermentum* P6-1 and was deposited on July 4, 2025, at the China Center for Type Culture Collection (CCTCC) with accession number CCTCC M 20251537, located at Wuhan University, Wuhan, China.

2. The microbial agent for fermenting Lactobacillus mucinus as described in claim 1.

3. The microbial agent according to claim 2, characterized in that, The bacterial agent is a bacterial suspension or fermentation broth of fermented Lactobacillus mucinus.

4. The application of the fermenting *Lactobacillus mucilaginosus* as described in claim 1 or the microbial agent as described in claim 2 in the production of extracellular polysaccharides.

5. An extracellular polysaccharide, characterized in that, The extracellular polysaccharide is obtained by fermentation of the fermenting *Lactobacillus mucilaginosus* according to claim 1 or the microbial agent according to claim 2.

6. The use of the fermented Lactobacillus mucinus as described in claim 1 or the microbial agent as described in claim 2 in the preparation of lipid-lowering drugs, health products or food.

7. The use of the fermented Lactobacillus mucinus as described in claim 1 or the microbial agent as described in claim 2 in the preparation of anti-inflammatory drugs, health products or food.

8. The use of the extracellular polysaccharide as described in claim 4 in the preparation of lipid-lowering drugs, health products or food.

9. The use of the extracellular polysaccharide as described in claim 4 in the preparation of anti-inflammatory drugs, health products or food.

Images