Microorganism, microbial agent, food, method for preparing food and method for inhibiting the growth of pathogenic bacteria in vitro

Abstract

The present invention discloses a microorganism, a microbial agent, a food and a method for preparing the food, and relates to the field of microorganisms. The microorganism is a submembrane Wickham yeast, and the deposit number is CGMCC No.30795. The submembrane Wickham yeast new strain screened by the present invention has a fast growth rate, strong acid and salt resistance, especially can still grow normally in a 3 mM nitrite environment, and can inhibit the growth of Escherichia coli and Staphylococcus aureus, and has a strong ability to metabolize nitrate; the fermented food prepared by the new strain has low salt content, healthy nutrition and unique flavor; the food fermentation process developed by the new strain has high fermentation efficiency, short production cycle and high application value.

Description

Technical Field

[0001] The present invention relates to the field of microorganisms, and in particular to a microorganism, a microbial agent, a food, a method for preparing the food, and a method for inhibiting the growth of pathogenic bacteria in vitro. Background Art

[0002] Salt is an essential ingredient in the processing of fermented peppers. It can reduce the water activity of peppers, inhibit the growth of spoilage bacteria, extend the shelf life of peppers, and improve the flavor of peppers. Traditional fermented peppers usually add 15-25% salt and rely on microorganisms attached to the surface of food raw materials for fermentation.

[0003] As the world advocates a low-sodium diet, reduced-salt fermented peppers are gaining more and more attention. Reduced-salt fermented peppers usually add 5-12% salt, but during the fermentation process, most yeasts still cannot avoid the reduction in viable counts due to salt stress. Therefore, under natural fermentation conditions, microorganisms grow slowly and the fermented food production cycle is long, making it difficult to meet the production scale of reduced-salt fermented food preparation.

[0004] Therefore, it is still necessary to screen yeasts with good salt and acid resistance and good fermentation performance to meet the development of salt-reduced fermented foods and their fermentation processes. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art to a certain extent. To this end, the present invention provides a submembrane Wickham yeast FVPHBJ24144 and its application. The present invention also provides a microbial agent, food or feed, a method for preparing food, and a method for inhibiting pathogenic bacteria in vitro. The submembrane Wickham yeast new strain screened by the present invention has the advantages of fast growth rate, strong acid and salt resistance, can inhibit the growth of Escherichia coli and Staphylococcus aureus, strong nitrate metabolism ability, etc. The fermented food prepared by using the new strain has low salt content, rich yeast content, healthy nutrition and unique flavor; the food fermentation process developed by using the new strain and microbial agent of the present invention has high fermentation efficiency, short production cycle and high application value.

[0006] Therefore, in the first aspect of the present invention, the present invention provides a microorganism. According to an embodiment of the present invention, the microorganism is submembrane Wickham yeast ( Wickerhamomyces subpelliculosus ), on May 27, 2024, it was deposited in the General Microbiology Center of China Microorganism Culture Collection Administration, with the deposit number CGMCC No.30795.

[0007] Collection information:

[0008] Strain name: Wickham yeast Wickerhamomyces subpelliculosus )FVPHBJ24144

[0009] Classification name: Submembrane Wickham yeast Wickerhamomyces subpelliculosus

[0010] Date of deposit: May 27, 2024

[0011] Depository: China National Microbiological Culture Collection Administration General Microbiology Center

[0012] Deposit number: CGMCC No.30795

[0013] Storage address: No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, Postal Code: 100101

[0014] The submembrane Wickham yeast ( Wickerhamomyces subpelliculosus ) The new strain FVPHBJ24144 grows fast and has strong acid and salt resistance, especially in a 3 mM nitrite environment, where it can still grow normally, and can inhibit the growth of Escherichia coli and Staphylococcus aureus, and has a strong ability to metabolize nitrate; the fermented food made using the new strain has a low salt content, rich yeast content, healthy nutrition, and unique flavor; the food fermentation process developed using the new strain has high fermentation efficiency, short production cycle, and high application value.

[0015] In a second aspect of the present invention, the present invention provides a microbial agent. According to an embodiment of the present invention, the microbial agent includes the aforementioned microorganisms.

[0016] In a third aspect of the present invention, the present invention provides a food or feed. According to an embodiment of the present invention, the food or feed includes at least one of the aforementioned microorganisms or the aforementioned microbial agents. The food or feed of the present invention has low salt content, rich yeast content, healthy nutrition, and unique flavor; the feed of the present invention has low salt content, rich yeast content, and high nutritional value.

[0017] In the fourth aspect of the present invention, the present invention proposes the use of the aforementioned microorganisms or the aforementioned microbial agents in the preparation of food or feed.

[0018] In a fifth aspect of the present invention, the present invention provides a method for preparing food. According to an embodiment of the present invention, the method comprises: fermenting the aforementioned microorganisms, one or more of the aforementioned microbial agents and food raw materials to be fermented to obtain the food. The method according to the embodiment of the present invention has high fermentation efficiency, short production cycle and high application value.

[0019] In a sixth aspect of the present invention, the present invention proposes a method for inhibiting the growth of pathogenic bacteria in vitro. According to an embodiment of the present invention, the method comprises: co-culturing at least one of the aforementioned microorganisms and the aforementioned microbial agents with a sample containing pathogenic bacteria; the pathogenic bacteria are selected from at least one of Staphylococcus aureus and Escherichia coli. According to the method of the embodiment of the present invention, submembrane Wickham yeast ( Wickerhamomyces subpelliculosus ) FVPHBJ24144 has an antibacterial effect and can effectively inhibit the growth of Staphylococcus aureus and Escherichia coli, and can be used to inhibit the growth of pathogens in vitro.

[0020] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0022] Figure 1 The submembrane Wickham yeast ( Wickerhamomyces subpelliculosus )The morphological identification results of FVPHBJ24144;

[0023] Figure 2 The submembrane Wickham yeast ( Wickerhamomyces subpelliculosus )Growth curve of FVPHBJ24144;

[0024] Figure 3 The submembrane Wickham yeast ( Wickerhamomyces subpelliculosus ) Absorbance values ​​(OD) of FVPHBJ24144 before and after culture in different pH medium 600 ) Survey results diagram;

[0025] Figure 4 The submembrane Wickham yeast ( Wickerhamomyces subpelliculosus )The results of the investigation on the number of viable bacteria of FVPHBJ24144 in culture medium with different pH values;

[0026] Figure 5 The submembrane Wickham yeast ( Wickerhamomyces subpelliculosus ) The absorbance values ​​(OD) of FVPHBJ24144 before and after culture in medium containing different salt concentrations 600 ) Survey results diagram;

[0027] Figure 6 The submembrane Wickham yeast ( Wickerhamomyces subpelliculosus )The results of the investigation of the number of viable bacteria of FVPHBJ24144 in culture medium containing different salt concentrations;

[0028] Figure 7 In the fermentation process of the fermented vegetables in Example 4 of the present invention, submembrane Wickham yeast ( Wickerhamomyces subpelliculosus )The results of the investigation on the number of viable bacteria of FVPHBJ24144;

[0029] Figure 8 The submembrane Wickham yeast ( Wickerhamomyces subpelliculosus )The results of the investigation on the inhibition of E. coli growth in the FVPHBJ24144 experimental group and the E. coli control group;

[0030] Figure 9 The submembrane Wickham yeast ( Wickerhamomyces subpelliculosus )The results of the investigation on the inhibition of Staphylococcus aureus growth by the FVPHBJ24144 experimental group and the Staphylococcus aureus control group;

[0031] Figure 10 The submembrane Wickham yeast ( Wickerhamomyces subpelliculosus ) Results of the investigation on the ability of FVPHBJ24144 to metabolize nitrate. DETAILED DESCRIPTION

[0032] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be understood as limiting the present invention.

[0033] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0034] In this document, the terms “include” or “comprising” are open expressions, that is, including the contents specified in the present invention but not excluding other contents.

[0035] As used herein, the terms "optionally", "optional" or "optionally" generally mean that the subsequently described event or circumstance may but need not occur, and that the description includes instances where the event or circumstance occurs and instances where it does not.

[0036] In this article, the term "YPD medium" refers to yeast culture medium, which can be divided into two categories: YPD solid culture medium and YPD liquid culture medium according to the content of coagulant (usually agarose).

[0037] In this article, the term "Wickham's yeast" refers to a yeast belonging to the phylum Ascomycota ( Ascomycota ) Saccharomyces ( Saccharomycetes ) Spore-forming yeasts ( Sporobolomycetales ) Sporobacteriaceae ( Sporobolomycetaceae ) Zygosaccharomyces ruckeri ( Zygosaccharomyces rouxii ), the colonies were medium-sized, white and round.

[0038] The present invention provides a microorganism, a microbial agent, a food or feed, a method for preparing a food, and a method for inhibiting pathogenic bacteria in vitro, which will be described in detail below.

[0039] microorganism

[0040] The present invention provides a microorganism. According to an embodiment of the present invention, the microorganism is submembrane Wickham yeast ( Wickerhamomyces subpelliculosus ), named FVPHBJ24144, and deposited on May 27, 2024 in the General Microbiology Center of China Culture Collection Administration, with the deposit address at No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing, Postal Code: 100101, and the deposit number is CGMCC No.30795.

[0041] According to an embodiment of the present invention, the 16s rDNA sequencing result of the microorganism is shown in SEQ ID NO: 1.

[0042] The submembrane Wickham yeast ( Wickerhamomyces subpelliculosus ) The new strain FVPHBJ24144 grows fast and has strong acid and salt resistance, especially in a 3 mM nitrite environment where it can still grow normally, and can inhibit the growth of Escherichia coli and Staphylococcus aureus, and has a strong ability to metabolize nitrate; the fermented food made using the new strain has a low salt content, rich yeast content, healthy nutrition, and unique flavor; the food fermentation process developed using the new strain has high fermentation efficiency, short production cycle, and high application value.

[0043] In this document, the term "Wickham's yeast ( Wickerhamomyces subpelliculosus )FVPHBJ24144" is synonymous with "submembrane Wickham yeast FVPHBJ24144".

[0044] Microbial Agents

[0045] The present invention provides a microbial agent. According to an embodiment of the present invention, the microbial agent includes the aforementioned microorganisms. The microbial agent of the present invention can be used to prepare fermented food, and after activation, it produces acid, which can be used to adjust the sour taste of food. In addition, the microbial agent can also inhibit the growth of pathogens such as Escherichia coli and Staphylococcus aureus.

[0046] In some specific embodiments, the microbial agent is a liquid microbial agent, and the concentration of the microorganism is 1×10 9 ~1×10 12 CFU / mL.

[0047] For example, the concentration of microorganisms in the aforementioned liquid microbial inoculant may be: 1×10 9 CFU / mL, 5×10 9 CFU / mL, 1×10 10 CFU / mL, 5×10 10 CFU / mL, 1×10 11 CFU / mL, 5×10 11 CFU / mL, 1×10 12 CFU / mL.

[0048] It should be noted that the microbial agent of the present invention may be a liquid microbial agent, including but not limited to fermentation products, etc.; it may also be a solid microbial agent, including but not limited to freeze-dried powder, etc.

[0049] It should be noted that, in the microbial agent of the present invention, the Wickham yeast may exist in the form of living cells and / or non-living cells.

[0050] As used herein, "living cells" refer to cells that have the ability to metabolize, reproduce or replicate.

[0051] Exemplarily, the living cells may be immobilized cells. Herein, "immobilized cells" refer to living cells that are fixed on a carrier and can carry out life activities such as growth, development, reproduction, inheritance and metabolism within a certain spatial range.

[0052] In this article, "non-living cells" refer to cells that do not have the ability to metabolize, reproduce and replicate, including but not limited to dry bacteria. Exemplarily, the microbial agent is a freeze-dried powder.

[0053] In some specific embodiments, the Wickham yeast FVPHBJ24144 exists in the form of living cells, dried bacteria, immobilized cells or any other forms.

[0054] In some specific embodiments, the dry bacteria are obtained by freeze-drying the submembrane Wickham yeast FVPHBJ24144.

[0055] In some specific embodiments, the microbial agent may further contain at least one strain acceptable to food or feed.

[0056] In some specific embodiments, the microbial agent further includes an adjuvant or carrier acceptable in food or an adjuvant or carrier acceptable in animal feed.

[0057] As used herein, "acceptable in food" refers to substances or compositions that can be consumed by humans, which may be adjusted according to the food requirements of different countries.

[0058] In this context, "adjuvant or carrier acceptable in animal feed" refers to a substance or composition that can be consumed by animals, which may be adjusted according to the animal feed requirements of different countries.

[0059] It should be noted that the characteristics and advantages described above for microorganisms are also applicable to the microbial agent and will not be repeated here.

[0060] Food or feed

[0061] The present invention provides a food or feed. According to an embodiment of the present invention, the food or feed comprises at least one of the aforementioned microorganisms or the aforementioned microbial agents. The food or feed of the present invention has low salt content, rich yeast content, is nutritious and healthy, and has a unique flavor.

[0062] According to an embodiment of the present invention, the invention further comprises an auxiliary material or a carrier acceptable to food or feed.

[0063] In some specific embodiments, the aforementioned microorganisms or the aforementioned microbial agents are added or inoculated into food, or added into feed, thereby further obtaining food or feed with low salt content, rich yeast content, healthy nutrition, and unique flavor.

[0064] Exemplarily, the food includes but is not limited to: probiotic tablets, fermented dairy products (such as probiotic yogurt), probiotic solid beverages, probiotic milk powder, probiotic cheese, probiotic soy products, probiotic candies, probiotic fermented vegetables, etc.

[0065] Exemplarily, the food includes but is not limited to: probiotic fermented feed.

[0066] It should be noted that the characteristics and advantages described above for microorganisms are also applicable to the food or feed and will not be repeated here.

[0067] use

[0068] The present invention also proposes the use of the aforementioned microorganism or the aforementioned microbial agent in preparing food or feed.

[0069] It should be noted that the characteristics and advantages described above for microorganisms are also applicable to this use and will not be repeated here.

[0070] method

[0071] The present invention provides a method for preparing food. According to an embodiment of the present invention, the method comprises: fermenting the aforementioned microorganisms, one or more of the aforementioned microbial agents and a food raw material to be fermented to obtain the food.

[0072] According to an embodiment of the present invention, the food raw materials include but are not limited to peppers, cabbages, cucumbers, and radishes.

[0073] The present invention also provides a method for inhibiting the growth of pathogenic bacteria in vitro. According to an embodiment of the present invention, the method comprises: co-culturing at least one of the aforementioned microorganisms and the aforementioned microbial agent with a sample containing pathogenic bacteria.

[0074] According to an embodiment of the present invention, the pathogenic bacteria is selected from at least one of Staphylococcus aureus and Escherichia coli.

[0075] It should be noted that the characteristics and advantages described above for microorganisms are also applicable to this method and will not be repeated here.

[0076] The scheme of the present invention will be explained below in conjunction with the embodiments. It will be appreciated by those skilled in the art that the following embodiments are only used to illustrate the present invention and should not be considered as limiting the scope of the present invention. Where specific techniques or conditions are not indicated in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. The reagents or instruments used are not indicated by the manufacturer and are all conventional products that can be obtained commercially.

[0077] Example 1: Obtaining submembrane Wickham yeast FVPHBJ24144

[0078] The submembrane Wickham yeast FVPHBJ24144 of the invention is separated and obtained from Hebei fermented chili sauce.

[0079] The process of strain collection and isolation: Take naturally fermented chopped pepper and add it to sterilized physiological saline. After mixing, dilute and spread it on YPD medium (10.0g peptone, 100g yeast extract powder, 200g glucose), at pH 6.0±0.2, 30℃, and incubate it for 24-48 hours. Pick out single colonies of different sizes and shapes and streak them on fresh YPD medium plates. Incubate them at 30℃ for 24-48 hours. Repeat the streak purification culture several times until the colonies in the plates are consistent in morphology and are identified after no foreign bacteria are found under microscopic examination.

[0080] Strain preservation: Mix the bacterial solution with sterile 50% glycerol in a freezing tube at a ratio of 1:1 and store at -80℃.

[0081] Example 2: Identification of Wickhamella submembranea FVPHBJ24144

[0082] The culture separated and purified in Example 1 was further confirmed to be a pure culture by streaking and smear microscopy, and then the strain morphology and physiological and biochemical identification, 16S rDNA gene PCR amplification and sequencing analysis were performed.

[0083] 1. Morphological and physiological and biochemical identification

[0084] With reference to the Manual of Systematic Identification of Common Fungi, FVPHBJ24144 was identified by its morphological characteristics, physiological and biochemical properties.

[0085] The identification results showed that the colony morphology on YPD agar medium was characterized by medium-sized, white, round ( Figure 1 ). The final pH in YPD liquid medium was 3.5.

[0086] 2. PCR amplification and sequencing analysis of 16S rDNA gene

[0087] The 16S rDNA sequence of Wickham's yeast FVPHBJ24144 was identified. PCR amplification conditions: 95℃ pre-denaturation for 10min, followed by 30 cycles: 94℃ denaturation for 30s, 56℃ annealing for 30s, 72℃ extension for 1.5min (1kb / min), 72℃ post-extension for 5min; 4℃ storage. The obtained PCR products were detected by 1% agarose gel electrophoresis, and the PCR reaction system is shown in Table 1.

[0088] Table 1 PCR reaction system

[0089]

[0090] The strains were sent to Shanghai Sangon Biotech Co., Ltd. for 16S rDNA sequence detection. The sequences were compared in GenBank, and a phylogenetic tree was constructed between the strains tested and other strains in the genus using MEGA11.0.13.

[0091] The results showed that the isolated strain FVPHBJ24144 was in the same branch as other strains of submembrane Wickham yeast. Wickerhamomyces subpelliculosus The 16S rDNA sequence homology of the strain was 99%. Combined with physiological and biochemical identification, FVPHBJ24144 was further confirmed to be a submembrane Wickham yeast, with the sequence accession number being CGMCC No.30795.

[0092] The final identification confirmed that the isolated strain was a submembrane Wickham yeast, named submembrane Wickham yeast FVPHBJ24144, which was deposited in the "General Microbiology Center of China Microbiological Culture Collection Administration" on May 27, 2024, with the deposit number CGMCC No.30795.

[0093] The 16S rDNA sequencing result of Wickhamella submembranea FVPHBJ24144 is shown in SEQ ID NO: 1.

[0094] (SEQ ID NO: 1).

[0095] Example 3: Submembrane Wickham yeast ( Wickerhamomyces subpelliculosus )Investigation on growth characteristics, acid production ability, acid resistance and salt resistance of FVPHBJ24144

[0096] In this example, the experimental strains were prepared as follows: Wickham's yeast ( Wickerhamomyces subpelliculosus) FVPHBJ24144 was streaked on a YPD agar plate for 24 to 48 h, and a single colony was picked and grown in YPD liquid medium for 16 to 20 h to obtain an activated strain.

[0097] 1. Strain growth characteristics and acid production capacity

[0098] The activated strain was inoculated into YPD liquid medium at 1% inoculation rate and cultured at 30°C. The absorbance at 600 nm was measured every 1 h until the stable period. The growth curve was drawn with the culture time as the horizontal axis and the corresponding absorbance value as the vertical axis ( Figure 2 ).

[0099] The results showed that in the first 24 h of culture, the submembrane Wickham yeast ( Wickerhamomyces subpelliculosus )FVPHBJ24144 grew and metabolized slowly; it entered the logarithmic growth phase after 24 hours. The pH of the bacterial solution was measured when it reached the stable phase and was basically maintained below 4.0.

[0100] 2. Acid resistance of the strain

[0101] The activated strain was inoculated into YPD liquid medium with different pH values ​​(pH values ​​of 3, 4, 5, and 6) at a 1% inoculation rate and cultured at 30°C for 24 h. The absorbance values ​​(OD600) of yeast before and after culture in medium with different pH values ​​were measured. Figure 3 ), and the number of live yeast cells before and after cultivation was determined by the culturable bacteria determination method ( Figure 4 ).

[0102] The results showed that the submembrane Wickham yeast FVPHBJ24144 had a high tolerance to acid. When the pH value of the YPD liquid medium was 4-6, the growth condition was good ( Figure 3 , Figure 4 ); when the pH value dropped to 3.5, the survival rate remained high and the number of viable bacteria was maintained at 10 7 CFU / mL or more ( Figure 4 ).

[0103] 3. Salt tolerance characteristics of strains

[0104] The activated strain was inoculated into YPD liquid medium containing different NaCl concentrations (0%, 4%, 8%, 10%, 15%, 20%) at a 1% inoculum and cultured at 3°C ​​for 24 h. The absorbance values ​​(OD600) of yeast before and after culture in medium with different salt concentrations were measured. Figure 5 ), and the number of live yeast cells before and after cultivation was determined by the culturable bacteria determination method ( Figure 6 ).

[0105] The results showed that the submembrane Wickham yeast FVPHBJ24144 had a high tolerance to NaCl. In a liquid medium with a salt concentration of 15%, the strain could still grow; in a liquid medium with a salt concentration of 20%, the number of viable bacteria was maintained at 10 7 CFU / mL or more ( Figure 6 ).

[0106] Example 4: Submembrane Wickham yeast ( Wickerhamomyces subpelliculosus )Application of FVPHBJ24144

[0107] In this example, the yeast Wickham submembrane ( Wickerhamomyces subpelliculosus )FVPHBJ24144 made fermented vegetables. The specific method is as follows:

[0108] 1. Wickham's yeast Wickerhamomyces subpelliculosus ) Preparation of FVPHBJ24144 starter culture

[0109] Wickham's yeast Wickerhamomyces subpelliculosus )FVPHBJ24144 was streaked on a YPD agar plate for 24-48 h, and a single colony was picked and grown in YPD liquid medium for 16-20 h for activation. The activated submembrane Wickham yeast FVPHBJ24144 was inoculated into YPD liquid medium at a 1% inoculum and expanded for 16-20 h. The bacterial solution was centrifuged, washed with sterile distilled water until no culture medium remained, and resuspended in sterile distilled water. The bacterial cell density was 1×10 10 ~1×10 11 CFU / mL.

[0110] 2. Fermented Vegetable Preparation

[0111] The fermented vegetables are prepared according to the following steps: 50.0 kg of fresh vegetables are selected, washed, drained, and crushed or not, 4.5 to 7.5 kg of salt is added and stirred evenly, the amount of salt added is 8% to 12% of the total vegetable weight, and 1% of the total vegetable weight of the submembrane Wickham yeast FVPHBJ24144 starter is inoculated, and the fermentation is sealed at room temperature for 30 days to obtain fermented vegetables made with submembrane Wickham yeast FVPHBJ24144 as a starter.

[0112] The results showed that the number of live yeast cells remained at 10 during the entire fermentation process. 5 CFU / mL or more ( Figure 7 ).

[0113] For example, vegetables suitable for making fermented vegetables using the submembrane Wickham yeast FVPHBJ24144 include, but are not limited to, peppers, cabbages, cucumbers, and radishes.

[0114] Example 5: Submembrane Wickham yeast ( Wickerhamomyces subpelliculosus )Investigation on the antibacterial properties of FVPHBJ24144

[0115] 1. Inhibit the growth of E. coli

[0116] Add 200 μL of distilled water and 10 μL of fermentation supernatant to A1-F1 of the 96-well plate, mix well, and add 100 μL of LB medium to each of the remaining wells. Pipette 100 μL of the mixture from wells A1-F1 and add it to wells A2-F2 and mix well. Pipette 100 μL from wells A2-F2 and add it to wells A3-F3 and mix well. And so on, until wells A10-F10. Take the cultured E. coli, use sterile water to prepare a bacterial suspension with a bacterial concentration equivalent to 0.5 McFarland turbidimetric standard, dilute it 1:1000 with LB medium, add 100 μL of bacterial suspension to wells 1-10 and well 12 of each row, and mix well. Place in a 37℃ incubator and incubate for 16-20 h. Measure the OD value every 1 h until the bacterial density is basically stable and stop measuring.

[0117] The results showed that the submembrane Wickham yeast FVPHBJ24144 could inhibit the growth of E. coli. Within a certain period of time, the concentration of E. coli in the experimental group was significantly lower than that in the control group ( Figure 8 ).

[0118] 2. Inhibit the growth of Staphylococcus aureus

[0119] Add 200 μL of distilled water and 10 μL of fermentation supernatant to A1-F1 of the 96-well plate, mix well, and add 100 μL of LB medium to each of the remaining wells. Aspirate 100 μL of the mixture from wells A1-F1 and add it to wells A2-F2 and mix well. Aspirate 100 μL from wells A2-F2 and add it to wells A3-F3 and mix well. And so on, until wells A10-F10. Take the cultured Staphylococcus aureus, use sterile water to prepare a bacterial suspension with a bacterial concentration equivalent to 0.5 McFarland turbidity standard, dilute it 1:1000 with LB medium, add 100 μL of bacterial suspension to wells 1-10 and well 12 of each row, and mix well. Place in a 37℃ incubator and incubate for 16-20 h. Measure the OD value every 1 h until the bacterial density is basically stable and stop measuring.

[0120] The results showed that the submembrane Wickham yeast FVPHBJ24144 could inhibit the growth of Staphylococcus aureus. Within a certain period of time, the concentration of Staphylococcus aureus in the experimental group was significantly lower than that in the control group ( Figure 9 ).

[0121] Example 6: Submembrane Wickham yeast ( Wickerhamomyces subpelliculosus)Investigation on the ability of FVPHBJ24144 to metabolize nitrate

[0122] In this example, the experimental strains were prepared as follows: the bacteria stored in a -80°C refrigerator were inoculated into a conical flask containing 100 mL of EM, and the culture was activated by shaking in a constant temperature shaker at 25°C and 160 rpm for 24 hours. After the culture was completed, the bacterial density was adjusted to about 2.0 (i.e., OD600 = 2.0) with sterile water.

[0123] Pipette 1 mL of bacterial suspension with OD600=2.0 into a new 99 mL EM conical flask. The EM without bacterial suspension is the blank control. Shake well and measure the OD value at 600 nm. Measure the OD value every 1 h until the bacterial density is basically stable and stop measuring. Add 5 mL of bacterial suspension with OD600=2.0 into a new 95 mL NM conical flask and analyze the changes in nitrate content to determine the strain's ability to metabolize nitrate. The above experiments all contain blank controls and three parallel groups.

[0124] The results showed that the submembrane Wickham yeast FVPHBJ24144 has a strong ability to metabolize nitrate. After 24 hours, the NaNO3 metabolism reached more than 75 mg / L ( Fig.10 ).

[0125] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0126] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A microorganism, characterized in that The microorganism is Wickham's yeast ( Wickerhamomyces subpelliculosus ), on May 27, 2024, it was deposited in the General Microbiology Center of China Microorganism Culture Collection Administration, with the deposit number CGMCC No.30795.

2. A microbial agent, characterized in that: The microorganism according to claim 1.

3. A food or feed, characterized in that It comprises at least one of the microorganisms described in claim 1 or the microbial agent described in claim 2.

4. Use of the microorganism according to claim 1 or the microbial agent according to claim 2 in the preparation of food or feed.

5. A method for preparing food, characterized in that: include: The food is obtained by fermenting one or more of the microorganisms according to claim 1 and the microbial agent according to claim 2 with food raw materials to be fermented.

6. The method according to claim 5, characterized in that The food raw materials include but are not limited to peppers, cabbages, cucumbers, and radishes.

7. A method for inhibiting the growth of pathogenic bacteria in vitro, characterized in that: include: Co-culturing at least one of the microorganisms of claim 1 and the microbial agent of claim 2 with a sample containing pathogenic bacteria; The pathogenic bacteria is selected from at least one of Staphylococcus aureus and Escherichia coli.

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