Propionibacterium freudenreichii subsp. shermanii strain PF37 with heat resistance and its application in intestinal colonization and symbiosis

Abstract

The present invention relates to the field of microbial technology, and specifically discloses a thermotolerant Propionibacterium freudenreichii subsp. shermanii strain PF37 and its application in intestinal colonization and symbiosis. The thermotolerant Propionibacterium freudenreichii subsp. shermanii strain PF37 was deposited with the China General Microbiological Culture Collection Center on March 21, 2025, and its deposit number is CGMCC No. 46389. This strain still has the ability of proliferation activity, fermenting and producing short-chain fatty acids, and promoting the colonization and proliferation of Bifidobacterium in the intestine at 34-37°C.

Description

Technical Field

[0001] The present invention belongs to the technical field of microorganisms, and in particular relates to a temperature-resistant Propionibacterium freudenreichii subsp. shermanii strain PF37 and its application in intestinal colonization and symbiosis. Background Art

[0002] Propionibacterium is a widely used bacterial species in the food industry, mainly used for cheese fermentation and maturation, preservation and nutrition addition. Propionibacterium freudenreichii ) is the primary species of Propionibacterium used in cheese fermentation. Propionibacterium can ferment a variety of substrates, such as lactic acid, sugars, glycerol, and amino acids, producing a variety of beneficial metabolites, such as short-chain fatty acids, B vitamins, conjugated linoleic acid, and bifidobacterium growth stimulator (BGF). It is these metabolites that provide Propionibacterium-fermented cheese with its unique flavor, extend its shelf life, and increase its nutritional value. In recent years, in addition to its application in dairy fermentation, Propionibacterium has increasingly attracted attention as a probiotic. Existing studies have found that the effective effects of Propionibacterium as a probiotic include: regulating the intestinal flora and maintaining intestinal microbial homeostasis; regulating the immune response and reducing intestinal inflammation; and producing beneficial metabolites such as short-chain fatty acids and vitamins.

[0003] Currently, most experiments on in vitro cultivation of Propionibacterium, in vitro evaluation of its ability to produce beneficial metabolites, and fermentation of vitamins by Propionibacterium use temperatures of 30°C or lower. For example, the optimal growth temperature for Propionibacterium freudenreichii subsp. schneiderii NHNK-616, described in CN118956702A, is 30°C.

[0004] However, these Propionibacterium bacteria cultured in vitro at 30°C are inhibited from growing and their probiotic properties are weakened when they enter the human body, where the body temperature is higher than the in vitro culture temperature. Studies have shown that elevated temperatures are detrimental to the growth and metabolism of Propionibacterium bacteria, such as reducing their growth rate, propionic acid production, biomass, and exopolysaccharide production.

[0005] Therefore, it is urgent to develop a Propionibacterium that is suitable for growing in the human body temperature environment. This is crucial for whether it can successfully colonize in the body, produce beneficial metabolites, and exert probiotic properties after entering the human body. Summary of the Invention

[0006] In order to solve the problems existing in the prior art, the purpose of the present invention is to provide a Propionibacterium that is resistant to human body temperature and can have proliferation activity and exert probiotic properties under human body temperature environment.

[0007] To achieve the object of the present invention, the technical solution of the present invention is as follows: In the first aspect, the present invention provides a thermotolerant Propionibacterium freudenreichii subsp. shermanii strain PF37 ( Propionibacterium freudenreichii subsp. shermanii ), and the thermotolerant Propionibacterium freudenreichii subsp. shermanii strain PF37 was deposited with the China General Microbiological Culture Collection Center on March 21, 2025. The address of the depositary institution is No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, and the deposit number is CGMCC No. 46389.

[0008] The thermotolerant Propionibacterium freudenreichii subsp. shermanii strain PF37 was isolated and screened from a cheese sample. After cultivation, the cell morphology is short rod-shaped, light milky white, arranged singly or in pairs, and without spores.

[0009] Furthermore, one of the characteristics of the strain is that it has proliferative activity in the environment of 30-40 °C, and particularly can exhibit proliferative activity different from other Propionibacterium at 34-37 °C.

[0010] Furthermore, the 16S rRNA sequence of the strain is as shown in SEQ ID NO.1.

[0011] Furthermore, the strain has the ability to ferment and produce short-chain fatty acids in the environment of 30-40 °C, and particularly can exhibit higher short-chain fatty acid production ability than other Propionibacterium at 34-37 °C.

[0012] In the specific embodiment of the present invention, acetic acid, propionic acid, and butyric acid are taken as typical non-limiting examples for illustration of short-chain fatty acids.

[0013] In the second aspect, the present invention provides a microbial preparation, and the microbial preparation contains the thermotolerant Propionibacterium freudenreichii subsp. shermanii strain PF37.

[0014] In the third aspect, the present invention provides the application of the thermotolerant Propionibacterium freudenreichii subsp. shermanii strain PF37 in the preparation of probiotic products, and the probiotic products have the function of improving intestinal health.

[0015] The probiotic products contain the strain or the microbial preparation.

[0016] Furthermore, the probiotic products are foods, drugs, or health products.

[0017] The foods include but are not limited to fermented fruits and vegetables, fermented milk, cheese, milk-containing beverages, milk powder, etc.

[0018] The drugs contain the strain, a drug carrier, and / or a pharmaceutical excipient.

[0019] Fourthly, the present invention provides the application of the thermotolerant Propionibacterium freudenreichii subsp. shermanii strain PF37 in promoting the colonization and proliferation of Bifidobacterium in the intestine. The thermotolerant Propionibacterium freudenreichii subsp. shermanii strain PF37 promotes the colonization and proliferation of Bifidobacterium in the intestine by colonizing in the intestine and symbiosis with it.

[0020] Based on this, the present invention also provides a composition, which comprises the thermotolerant Propionibacterium freudenreichii subsp. shermanii strain PF37 and Bifidobacterium.

[0021] The raw materials or reagents involved in the present invention are all ordinary commercially available products, and the operations involved are all conventional operations in the art without special instructions.

[0022] The beneficial effects of the present invention are as follows:

[0023] (1) A Propionibacterium freudenreichii subsp. shermanii strain PF37 is isolated and screened from cheese samples. The Propionibacterium freudenreichii subsp. shermanii strain PF37 can grow normally at 34°C to 40°C, has the ability to tolerate acid and bile salts, and can show a higher in vivo colonization rate, and can produce more beneficial metabolites in vivo, such as short-chain fatty acids, etc.

[0024] (2) The Propionibacterium freudenreichii subsp. shermanii strain provided by the present invention shows a metabolic synergistic effect with Bifidobacterium during co-culture at 34°C to 40°C, and can promote the colonization and proliferation of Bifidobacterium in the intestine. Description of the Drawings

[0025] Figure 1 It is a picture of the colony morphology of Propionibacterium freudenreichii subsp. shermanii PF37;

[0026] Figure 2 It is a Gram staining picture of Propionibacterium freudenreichii subsp. shermanii PF37;

[0027] Figure 3 It is an evolutionary tree of the 16S rRNA gene of 6 Propionibacterium freudenreichii subsp. shermanii strains;

[0028] Figure 4 It is a comparison chart of the growth curves of 10 Propionibacterium freudenreichii subsp. shermanii strains from different sources at a fermentation temperature of 30°C;

[0029] Figure 5 It is a comparison chart of the growth curves of 10 Propionibacterium freudenreichii subsp. shermanii strains from different sources at a fermentation temperature of 34°C;

[0030] Figure 6 It is a comparison chart of the growth curves of 10 Propionibacterium freudenreichii subsp. shermanii strains from different sources at a fermentation temperature of 37°C;

[0031] Figure 7Comparison chart of acetic acid produced by 10 Propionibacterium freudenreichii subsp. shermanii strains from different sources after anaerobic culture at 37°C for 3 days;

[0032] Figure 8 Comparison chart of propionic acid produced by 10 Propionibacterium freudenreichii subsp. shermanii strains from different sources after anaerobic culture at 37°C for 3 days;

[0033] Figure 9 Acid tolerance comparison chart of 10 Propionibacterium freudenreichii subsp. shermanii strains from different sources;

[0034] Figure 10 Bile salt tolerance comparison chart of 10 Propionibacterium freudenreichii subsp. shermanii strains from different sources;

[0035] Figure 11 Comparison chart of acetic acid content in mouse feces after intervention with different strains;

[0036] Figure 12 Comparison chart of propionic acid content in mouse feces after intervention with different strains;

[0037] Figure 13 Comparison chart of butyric acid content in mouse feces after intervention with different strains. Detailed implementation mode

[0038] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the solution of the present invention will be further described below. It should be noted that, without conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0039] Many specific details are set forth in the following description in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways different from those described herein; obviously, the embodiments in the specification are only a part of the embodiments of the present invention, rather than all of the embodiments.

[0040] The preferred embodiments of the present invention will be described in detail below in conjunction with the embodiments. It should be understood that the following embodiments are given only for the purpose of illustration, and are not used to limit the scope of the present invention. Those skilled in the art can make various modifications and substitutions to the present invention without departing from the purpose and spirit of the present invention.

[0041] The experimental methods used in the following examples are all conventional methods unless otherwise specified.

[0042] The materials, reagents, etc. used in the following examples can be obtained from commercial sources unless otherwise specified.

[0043] The YEL medium used in the following examples has the following composition: 21.6 g / L of 60% lactic acid solution, 10 g / L of yeast powder, 10 g / L of peptone, 0.328 g / L of dipotassium hydrogen phosphate, and 0.056 g / L of manganese sulfate.

[0044] The fermentation medium used in the following examples has the following composition: 10 g / L of glucose, 10 g / L of lactose, 20 g / L of yeast extract, 20 g / L of peptone, 2 g / L of dipotassium hydrogen phosphate, 5 g / L of sodium acetate, 0.15 g / L of magnesium sulfate, and 0.05 g / L of manganese sulfate.

[0045] The strains CICC10284, ATCC9614, BNCC353332, and PF-G68 used in the following examples were all obtained through commercial channels.

[0046] Example 1

[0047] Source, isolation, and identification of Propionibacterium freudenreichii subsp. shermanii strain PF37.

[0048] Propionibacteria can effectively utilize lactic acid as a carbon source for growth and propagation. The YEL medium is a medium containing lactic acid and is suitable for the screening and cultivation of Propionibacteria. Its composition is: 21.6 g / L of 60% lactic acid solution, 10 g / L of yeast powder, 10 g / L of peptone, 0.328 g / L of dipotassium hydrogen phosphate, and 0.056 g / L of manganese sulfate.

[0049] Fermenting Propionibacteria requires a fermentation medium with richer nutrients. Its composition is: 10 g / L of glucose, 10 g / L of lactose, 20 g / L of yeast extract, 20 g / L of peptone, 2 g / L of dipotassium hydrogen phosphate, 5 g / L of sodium acetate, 0.15 g / L of magnesium sulfate, and 0.05 g / L of manganese sulfate.

[0050] Cut a small piece of cheese and place it in the YEL medium. Incubate anaerobically at 37°C for 3 days. Dilute the culture solution and spread it on the YEL agar plate. Incubate anaerobically at 37°C for 5 days. Pick a single colony and inoculate it into a fresh YEL liquid medium for cultivation. After PCR amplification and sequencing alignment, a strain of Propionibacterium freudenreichii subsp. shermanii was obtained and named Propionibacterium freudenreichii subsp. shermanii PF37 ( Propionibacterium freudenreichii subsp. shermanii )

[0051] The colony morphology of Propionibacterium freudenreichii subsp. shermanii PF37 is shown as Figure 1 follows. On the YEL agar plate, after anaerobic incubation at 37°C for 5 days, Propionibacterium freudenreichii subsp. shermanii PF37 forms round, convex in the middle, neat edges, and smooth-surfaced light milky white colonies.

[0052] After Propionibacterium freudenreichii subsp. shermanii PF37 is Gram-stained, it is observed to be Gram-positive under a microscope, without spores, and the bacterial morphology is short rod-shaped, arranged singly or in pairs, as Figure 2 shown.

[0053] Take the culture solution of Propionibacterium freudenreichii subsp. shermanii PF37, amplify the 16S rRNA gene fragment of the bacteria by PCR technology, and compare the sequencing result of the amplified product with the NCBI database. The comparison result shows that this strain is Propionibacterium freudenreichii subsp. shermanii ( Propionibacterium freudenreichii subsp. shermanii ), and the sequencing sequence is shown in SEQ ID NO.1.

[0054] The above-mentioned Propionibacterium freudenreichii subsp. shermanii PF37 was deposited in the General Microbiology Center of the China Committee for Culture Collection of Microorganisms (Address: No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing), and the deposit number is CGMCC No. 46389, and the taxonomic name is: Propionibacterium freudenreichii subsp. shermanii , and the deposit date is March 21, 2025.

[0055] Example 2

[0056] Growth characteristics of Propionibacterium freudenreichii subsp. shermanii PF37.

[0057] In order to compare and observe the growth characteristics of Propionibacterium freudenreichii subsp. shermanii PF37, four commercial Propionibacterium freudenreichii subsp. shermanii strains (CICC10284, ATCC9614, BNCC353332, PF-G68) and another five Propionibacterium freudenreichii subsp. shermanii strains (PF051, PF087, PF135, PF172 and PF184) screened from cheese by the method of the example were selected as control strains. The 16S rRNA sequences of the five strains are shown in SEQ ID NO.2, SEQ ID NO.3, SEQ ID NO.4, SEQ ID NO.5, and SEQ ID NO.6 respectively. The phylogenetic tree of the six 16S rRNA genes screened this time is as Figure 3 shown.

[0058] Resuscitate the Propionibacterium freudenreichii subsp. shermanii PF37 strain and the control strains with fresh YEL medium. After subculturing once, culture the seed liquid until OD600 is 3.0, and inoculate the seed liquid into a glass fermenter containing 2 L of fermentation medium at an inoculation amount of 5% for anaerobic fermentation. The fermentation temperatures are set at 30 °C, 34 °C and 37 °C respectively, and other fermentation parameters are the same: pH value 6.5, stirring at 50 rpm, and fermentation duration 96 hours. Sampling is carried out every 12 hours to measure the OD 600 absorbance value of the culture solution.

[0059] From Figures 4 - 6It can be seen that at a culture temperature of 30 °C, the growth of 10 strains of bacteria was normal, and the logarithmic growth phase was from 24 to 60 hours. Except for the two strains BNCC353332 and PF172 with low OD 600 absorbance values, the OD 600 absorbance values of other strains in the stationary phase were all above 20. When the culture temperature was raised to 34 °C, the growth rate of the control strain was inhibited, and the OD 600 absorbance value was lower than that at a culture temperature of 30 °C, while the OD 600 absorbance value of Propionibacterium freudenreichii subsp. shermanii PF37 decreased insignificantly. When the culture temperature was raised to 37 °C, only Propionibacterium freudenreichii subsp. shermanii PF37 grew without being inhibited, and the OD 600 absorbance values of the other 9 strains in the stationary phase all decreased further. After fermentation for 72 hours under the culture condition of 37 °C, the OD 600 absorbance value of Propionibacterium freudenreichii subsp. shermanii PF37 was more than 94% higher than that of the control strain.

[0060] This indicates that Propionibacterium freudenreichii subsp. shermanii PF37 is a strain of propionibacterium that can adapt to human body temperature, and the increase in temperature after colonization in the human body has no inhibitory effect on the growth of the strain.

[0061] Example 3

[0062] Ability of Propionibacterium freudenreichii subsp. shermanii PF37 to produce short-chain fatty acids during in vitro culture at 37 °C.

[0063] Propionibacterium freudenreichii subsp. shermanii PF37 and the control strain were inoculated into 50 mL of fermentation medium and anaerobically cultured for 3 days. The culture temperature was 37 °C. After the culture was completed, the supernatant was obtained by centrifugation, filtered through a 0.22 μm membrane, and the filtrate was used to determine the concentration of short-chain fatty acids by high-performance liquid chromatography.

[0064] From Figures 7 - 8 It can be seen that compared with the control strain, Propionibacterium freudenreichii subsp. shermanii PF37 produced more acetic acid and propionic acid at a culture temperature of 37 °C. The acetic acid content in the fermentation broth of Propionibacterium freudenreichii subsp. shermanii PF37 was 1.253 mg / mL, which was more than 2.96 times that of the control strain, and the propionic acid content was 2.206 mg / mL, which was more than 4.38 times that of the control strain.

[0065] Example 4

[0066] Acid and bile salt tolerance of Propionibacterium freudenreichii subsp. shermanii PF37.

[0067] Propionibacterium freudenreichii subsp. schefflerae PF37 and a control strain were inoculated into YEL medium and cultured anaerobically for 3 days at 30°C. After incubation, the supernatant was centrifuged, resuspended in YEL medium (pH 2.0), and incubated at 37°C for 3 hours. The bacterial cultures before and after incubation were plated and counted to calculate the acid-resistant survival rate.

[0068] Propionibacterium freudenreichii subsp. schefflerae PF37 and a control strain were inoculated into YEL medium and cultured anaerobically for 3 days at 30°C. After incubation, the supernatant was centrifuged, resuspended in YEL medium containing 0.3% bile salts, and incubated at 37°C for 3 hours. The bacterial cultures before and after incubation were plated and counted to calculate the bile salt-tolerant survival rate.

[0069] The results are as follows Figures 9 - 10 As shown, the survival rate of Propionibacterium freudenreichii subsp. shenri PF37 did not decrease significantly after being incubated in acidic YEL medium and YEL medium containing bile salts, indicating that Propionibacterium freudenreichii subsp. shenri PF37 has strong acid and bile salt tolerance.

[0070] Example 5

[0071] The ability of Propionibacterium freudenreichii subsp. schreiberi to produce short-chain fatty acids in vivo.

[0072] Propionibacterium freudenreichii subsp. cheleriana CICC10284, ATCC9614, PF37, PF135, and PF184 were revived and inoculated into YEL medium for anaerobic culture for 3 days. The culture temperature was 30°C. After the culture was completed, the supernatant was removed by centrifugation, and the supernatant was removed after resuspending and washing with physiological saline. The supernatant was removed by centrifugation and resuspended in physiological saline to 1×10 10 CFU / mL, used for oral gavage intervention in mice, 100 μL per mouse per day.

[0073] Six-week-old C57 mice were purchased and, after one week of acclimation, divided into six groups of 10 mice each. The experimental group mice were gavaged with the aforementioned strain suspension, while the blank control group mice were gavaged with an equal volume of saline. The gavage intervention lasted one month.

[0074] After the intervention, the feces of the mice were collected, and methanol (10 times the weight of the feces) was added and mixed. After ultrasonic homogenization, the insoluble particles were removed by centrifugation, and the filtrate was collected for gas chromatography-mass spectrometry analysis. Figures 11 - 13As shown in the figure, compared with the blank control group (Control), the intervention of the control strain in the experimental group did not significantly increase the content of short-chain fatty acids in the feces. However, after the intervention with Propionibacterium freudenreichii subsp. shermanii PF37 strain, the content of short-chain fatty acids increased significantly. The content of acetic acid increased by 72.10%, the content of propionic acid increased by 184.98%, and the content of butyric acid increased by 43.14%. Compared with the control strain, strain PF37 produced 43.52% - 72.09% more acetic acid, 77.64% - 184.98% more propionic acid, and 27.21% - 87.94% more butyric acid in vivo. This indicates that Propionibacterium freudenreichii subsp. shermanii PF37 strain has a stronger ability to produce short-chain fatty acids in vivo.

[0075] Example 6

[0076] Colonization of Propionibacterium freudenreichii subsp. shermanii PF37 in vivo and its ability to promote Bifidobacterium.

[0077] Take the feces of mice after the intervention in Example 5 (day 0), and the feces on the 3rd and 7th days after the intervention, put them into sterile EP tubes, and extract DNA according to the operation instructions of the QIAGEN fecal DNA extraction kit. Use fluorescence quantitative PCR to determine the content of Propionibacterium and Bifidobacterium. The quantitative primer sequences for Propionibacterium are SEQ ID NO.7 and SEQ ID NO.8: 5’-ATTCCATCGCCCTGAAGGA-3’; 5’-TTGATCTGCGTCTTCTGGCC-3’. The quantitative primer sequences for Bifidobacterium are SEQID NO.9 and SEQ ID NO.10: 5’-CGCGTCYGGTGTGAAAG-3’; 5’-CCCCACATCCAGCATCCA-3’. To prepare the standard curve of the viable count of bacteria, take the Propionibacterium freudenreichii subsp. shermanii PF37 bacterial solution and the Bifidobacterium animalis subsp. lactis BB-12 bacterial solution whose viable count has been calculated by plating, and extract genomic DNA according to the operation instructions of the extraction kit. Dilute with sterile water, and dilute the genomic DNA of the two strains to 1.0×10 7 CFU / mL, and then dilute it ten-fold with sterile water to 1.0×10 1 CFU / mL. Use the genomic DNA at 7 dilution concentrations as templates for fluorescence quantitative PCR amplification. After the amplification is completed, use the logarithm of the genomic DNA concentration as the abscissa and the Ct value as the ordinate to draw the standard curve. Use the mouse fecal DNA as the template for fluorescence quantitative PCR amplification, and calculate the content of the two bacteria in the mouse feces according to the Ct value and the standard curve.

[0078] As can be seen from Table 1, compared with other strains, on the 0th day, the content of Propionibacterium in the Propionibacterium freudenreichii subsp. shermanii PF37 group was 21.45 - 48.32 times that of other control strain groups. On the 3rd and 7th days after the intervention stopped, the content of Propionibacterium in other control strain groups decreased significantly. On the 7th day, a large amount of Propionibacterium still remained in the feces of the Propionibacterium freudenreichii subsp. shermanii PF37 group, indicating that Propionibacterium freudenreichii subsp. shermanii PF37 has a stronger colonization ability in the body than other strains.

[0079]

[0080] As can be seen from Table 2, compared with the blank control group (Control), the intervention with Propionibacterium freudenreichii subsp. shermanii PF37 strain significantly increased the content of Bifidobacterium. Compared with the control strain group, the content of Bifidobacterium in the Propionibacterium freudenreichii subsp. shermanii PF37 group also increased significantly. The content of Bifidobacterium in the Propionibacterium freudenreichii subsp. shermanii PF37 group was 10.38 - 29.11 times that of other control strain groups. On the 3rd and 7th days after the intervention stopped, more Bifidobacterium was also found in the feces of mice in the Propionibacterium freudenreichii subsp. shermanii PF37 group. This indicates that the colonization of Propionibacterium freudenreichii subsp. shermanii PF37 strain promotes the colonization and proliferation of Bifidobacterium in the intestine.

[0081]

[0082] Based on the in - vivo experimental results of Example 5 and Example 6, it can be seen that Propionibacterium freudenreichii subsp. shermanii PF37 provided by the present invention has a stronger ability to adapt to body temperature, can colonize better in the body, reproduce and expand in the intestine, maintain higher metabolic activity, and produce more beneficial metabolites.

[0083] It should be noted that in this article, the term "including", "comprising" or any other variant thereof is intended to cover non - exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes elements inherent to such process, method, article or device.

[0084] The above - mentioned are only specific embodiments of the present invention, enabling those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be obvious to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments described herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A temperature-resistant Propionibacterium freudenreichii subsp. shermanii strain PF37, characterized in that, The strain PF37 was deposited at the General Microbiological Center of the China Committee for Culture Collection of Microorganisms on March 21, 2025, with the deposit number CGMCC No. 46389, and the taxonomic name is Propionibacterium freudenreichii subsp. Shermanii , The strain PF37 has the ability to promote the colonization and proliferation of Bifidobacterium in the intestine in vivo.

2. The Propionibacterium freudenreichii subsp. shermanii strain PF37 with heat resistance as described in claim 1, characterized in that, The described strain has proliferative activity in an environment of 34 - 37°C.

3. The Propionibacterium freudenreichii subsp. shermanii strain PF37 with heat resistance as described in claim 1, characterized in that, The described strain has the ability to ferment and produce short-chain fatty acids in an environment of 34 - 37°C.

4. A microbial preparation, characterized in that, The microbial preparation contains the thermotolerant Propionibacterium freudenreichii subsp. shermanii strain PF37 as claimed in claim 1.

5. Use of the thermotolerant Propionibacterium freudenreichii subsp. shermanii strain PF37 as claimed in claim 1 in the preparation of a probiotic product.

6. The application according to claim 5, characterized in that, The probiotic product is a food, a medicine or a health product.

7. A probiotic product, characterized in that, The probiotic product contains the strain as claimed in claim 1 and / or the microbial preparation as claimed in claim 4.

8. Use of the thermotolerant Propionibacterium freudenreichii subsp. shermanii strain PF37 as claimed in claim 1 in promoting the colonization and proliferation of Bifidobacterium in the intestine.

9. The application according to claim 8, wherein The thermotolerant Propionibacterium freudenreichii subsp. shermanii strain PF37 promotes the colonization and proliferation of Bifidobacterium in the intestine and symbiosis with it by colonizing the intestine.

10. A composition, characterized in that, Contains Bifidobacterium and the thermotolerant Propionibacterium freudenreichii subsp. shermanii strain PF37 as claimed in claim 1.

Images