Monosporozyma servazzii and use thereof

Abstract

The present invention provides Monosporozyma servazzii. The Monosporozyma servazzii is the Monosporozyma servazzii strain AMCC 31719, which is deposited at the China Center for Type Culture Collection (CCTCC) under the accession number CCTCC NO: M 20242063. The Monosporozyma servazzii strain of the present invention is capable of utilizing multiple carbon sources during growth and is characterized by high glycerol and β-glucosidase production, and aroma production. The strain can enhance the flavor of baked products and improve the texture thereof, and is mainly applicable in the fields of food and fermented food.

Description

A type of *Saccharomyces cerevisiae* and its applications

[0001] Related applications

[0002] This application claims priority to the earlier application No. 202510206265.5 filed with the China National Intellectual Property Administration on February 24, 2025, and to the earlier application No. 202510435659.8 filed with the China National Intellectual Property Administration on April 8, 2025, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to the field of microbiology, specifically to a type of *Saccharomyces cerevisiae* and its applications. Background Technology

[0004] Monosporozyma servazzii is present in traditional sauerkraut, kimchi, fermented sausages, and fermented pasta. Chang Hee Jeong et al. demonstrated through cell experiments, animal experiments, and genomic analysis that Monosporozyma servazzii is safe for food (CH Jeong, Kim JY, OhY-J, et al. Safety assessment of white colony-forming yeasts in kimchi[J]. Food Microbiol, 2022, 106104057.). In the fermentation of vegetables and meats, Monosporozyma servazzii primarily functions by producing ethanol, which reacts with organic acids to generate aromatic substances such as esters, enriching the flavor of the food. In pasta products, patent CN117229930A reports a strain of Monosporozyma servazzii that increases the viscosity of food by producing polysaccharide compounds, making pasta more chewy. Patent KR101975105B1 describes the isolation of a strain of *Monosporium serosa* with excellent gas-producing capabilities from apple preserves, which can be used as a leavening agent in baked goods. *Monosporium serosa* shows potential in the field of flour products. Previous researchers have explored its applications in flour products based on its gas-producing and polysaccharide properties, but there are no reports on its potential in delaying bread staling and enhancing the flavor of flour products.

[0005] A key indicator of bread staling is increased hardness. The key to bread softness lies primarily in its fluffiness and moisture. Regarding fluffiness, the food industry has industrially available brewer's yeast strains with excellent gas-producing properties that allow dough to expand quickly and fully. As for moisture, bread production often uses humectant additives to enhance softness. However, with increasing public awareness of health and the growing advocacy for additive-free and other healthy eating habits, the addition of humectant additives clearly contradicts the current pursuit of purely natural foods and simple recipes. Summary of the Invention

[0006] This invention addresses the problem of bread staling, which is often addressed by adding moisturizing additives to improve softness during bread production. It provides a strain of *Monosporium serrulatum* and its application. This yeast strain can delay bread staling, reduce changes in bread hardness during storage, maintain bread softness, and enhance aroma in bread products.

[0007] Specifically, the present invention proposes the following technical solution:

[0008] Technical Solution 1: A Monosporozyma servazzii strain, characterized in that the Monosporozyma servazzii strain is AMCC 31719, which is deposited at the China Center for Type Culture Collection (CCTCC) with accession number CCTCC NO:M 20242063.

[0009] Technical Solution 2: According to Technical Solution 1, the *Saccharomyces cerevisiae* strain AMCC 31719 has the following ITS gene sequence as shown in SEQ ID NO.3.

[0010] Technical Solution 3: According to Technical Solution 1 or 2, the Saccharomyces cerevisiae is characterized in that the carbon source available to the Saccharomyces cerevisiae AMCC 31719 strain includes one or more of the following substances selected from the group consisting of glucose, galactose, xylose, melibiose, maltose, cellobiose, inulin, stachyose, trehalose, glycerol and fructose.

[0011] Technical Solution 4: According to any one of Technical Solutions 1-3, the *Saccharomyces cerevisiae* strain AMCC 31719 has the ability to produce glycerol, lactic acid, maltose monohydrate, fructose, succinic acid and / or ethanol.

[0012] Preferably, the glycerol content in the fermentation broth of *Saccharomyces cerevisiae* is ≥7.5 g / L; more preferably, the glycerol content in the fermentation broth of *Saccharomyces cerevisiae* is 7.5-7.7 g / L.

[0013] Preferably, the fermentation broth of the *Monosporium sericeum* contains lactic acid content greater than or equal to 659.90 μg / mL, maltose monohydrate content greater than or equal to 1330.90 μg / mL, fructose content greater than or equal to 864.80 μg / mL, succinic acid content greater than or equal to 1748.20 μg / mL, and ethanol content greater than or equal to 43115.30 μg / mL. Specifically, the lactic acid content is 659.90-794.10 μg / mL, the maltose monohydrate content is 1330.90-1365.00 μg / mL, the fructose content is 864.80-1101.00 μg / mL, the succinic acid content is 1748.20-1816.50 μg / mL, and the ethanol content is 43115.30-43191.50 μg / mL.

[0014] More preferably, the fermentation broth of *Saccharomyces cerevisiae* refers to: inoculating the activated *Saccharomyces cerevisiae* broth into YPD liquid medium, and culturing it at 30°C and 180 rpm for 12-36 hours to obtain a viable count of 2 × 10⁻⁶ cells / day. 8 -5×10 8 The fermentation broth of *Saccharomyces cerevisiae* with a concentration of CFU / mL is obtained by separating the solid and liquid components of the fermentation broth and retaining the supernatant.

[0015] Technical Solution 5: The *Saccharomyces cerevisiae* strain according to any one of technical solutions 1-4, characterized in that the *Saccharomyces cerevisiae* AMCC 31719 strain produces β-glucosidase.

[0016] Technical Solution 6: According to any one of Technical Solutions 1-5, the *Saccharomyces cerevisiae* strain AMCC 31719 produces aroma and flavor substances, which include alcohols, esters, aldehydes and ketones.

[0017] Preferably, the alcohols include linalool, isoamyl alcohol, phenethyl alcohol, and / or nerol;

[0018] And / or, the esters include isoamyl acetate, phenethyl acetate and / or ethyl decanoate;

[0019] And / or, the aldehydes include nonanal and / or phenylacetaldehyde;

[0020] And / or, the ketones include acetoin;

[0021] More preferably, the flavoring substance includes acetoin.

[0022] Technical Solution 7: According to the *Saccharomyces cerevisiae* of Technical Solution 6, the concentration of linalool in the alcohols is 33-38 μg / L, and / or the concentration of isoamyl alcohol is 12000-12400 μg / L, and / or the concentration of phenylethanol is 13100-13500 μg / L, and / or the concentration of nerolidol is 1000-1210 μg / L;

[0023] And / or, the concentration of isoamyl acetate in the ester is 26-30 μg / L, and / or the concentration of phenethyl acetate is 24000-24200 μg / L, and / or the concentration of ethyl decanoate is 100-130 μg / L.

[0024] And / or, the concentration of nonanal in the aldehyde is 14-18 μg / L, and / or the concentration of phenylacetaldehyde is 17-21 μg / L;

[0025] And / or, the concentration of acetoin in the ketone is 350-400 μg / L.

[0026] Preferably, L refers to the volume of the fermentation broth of *Saccharomyces cerevisiae*, wherein the activated *Saccharomyces cerevisiae* broth is inoculated into YPD liquid medium and cultured at 30°C and 180 rpm for 12-36 hours to obtain a viable count of 2 × 10⁻⁶ cells / day. 8 -5×10 8 The fermentation broth of *Saccharomyces cerevisiae* with a concentration of CFU / mL is obtained by separating the solid and liquid components of the fermentation broth and retaining the supernatant.

[0027] Technical Solution 8: A microbial agent, characterized in that the microbial agent comprises the *Saccharomyces cerevisiae* AMCC 31719 strain as described in any one of Technical Solutions 1-7.

[0028] Technical Solution 9: The microbial agent according to Technical Solution 8 is characterized in that the microbial agent further includes excipients.

[0029] Technical Solution 10: A fermentation product, characterized in that the fermentation product is prepared by fermentation using the *Saccharomyces cerevisiae* AMCC 31719 strain described in any one of Technical Solutions 1-7 or the inoculum described in Technical Solutions 8 or 9.

[0030] Technical Solution 11: A method for preparing the fermented product, characterized in that the method includes the following steps: culturing the *Saccharomyces cerevisiae* AMCC 31719 strain as described in any one of technical solutions 1-7 or the inoculum as described in technical solutions 8 or 9.

[0031] Technical Solution 12: The preparation method according to Technical Solution 11 is characterized in that the preparation method includes the following steps:

[0032] (1) The above-mentioned *Saccharomyces cerevisiae* AMCC 31719 strain or the above-mentioned inoculum agent is cultured in a large scale.

[0033] (2) Add the product obtained in step (1) to the culture medium and ferment it at 10-45℃ to obtain the fermentation product;

[0034] Preferably, the fermentation product can be any one of the following: original fermentation broth, wet cell culture, or fermentation supernatant. The original fermentation broth refers to a mixture containing cell culture, metabolites, and unconsumed culture medium. The wet cell culture refers to the cell precipitate obtained after solid-liquid separation of the original fermentation broth. The fermentation supernatant refers to the supernatant obtained after solid-liquid separation of the original fermentation broth and removal of the precipitate.

[0035] Technical Solution 13: The application of the fermentation product prepared by the preparation method of any one of Technical Solutions 1-7, or the microbial agent of Technical Solution 8 or 9, or the fermentation product of Technical Solution 10, or the fermentation product of Technical Solution 11 or 12, in the preparation of food, food additives, feed, pharmaceuticals, or health products.

[0036] Preferably, the application of *Saccharomyces cerevisiae* as described in any one of technical solutions 1-7 or the microbial agent as described in technical solution 8 or 9 in the preparation of food, feed, pharmaceuticals, or health products.

[0037] Preferably, the fermented product prepared by the method described in technical solution 10 or technical solution 11 or 12 is used in the preparation of food, food additives or feed.

[0038] Technical Solution 14: According to the application described in Technical Solution 13, the application is characterized in that the application in the preparation of food additives includes the application in the preparation of moisturizing food additives or the preparation of edible flavorings.

[0039] Technical solution 15: The application according to technical solution 13 or 14 is characterized in that the application in food preparation includes the application in the preparation of baked goods;

[0040] Preferably, the baked goods include bread, pastries, biscuits, steamed buns and / or dumplings;

[0041] More preferably, in the preparation of baked goods, the *Saccharomyces cerevisiae* and *Saccharomyces cerevisiae* are used for synergistic fermentation.

[0042] Technical Solution 16: According to the application described in Technical Solution 15, the characteristic is that, in the preparation of baked goods, moisturizing components are produced during the early fermentation of the baked goods, thereby delaying the aging of the baked goods.

[0043] Technical solution 17: The application according to technical solution 15 or 16 is characterized in that, in the preparation of baked goods, the aroma of baked goods is enhanced;

[0044] Preferably, the baked food contains alcohols, esters, ketones, aldehydes and / or phenolic flavor substances;

[0045] And / or, alcohol flavorings include n-hexanol, isoamyl alcohol, and / or phenylethanol;

[0046] And / or, ester flavor compounds include γ-nonanolactone;

[0047] And / or, ketone flavor compounds include acetoin and / or ethylcyclopentenolone;

[0048] And / or, aldehyde flavorings include n-pentanal;

[0049] And / or, phenolic flavor compounds include maltol.

[0050] Technical Solution 18: According to the application described in Technical Solution 17, the content of n-hexanol in the alcohol flavor substance is 410-430 μg / kg, and / or the content of isoamyl alcohol is 4000-4300 μg / kg, and / or the content of phenylethanol is 4700-4900 μg / kg, calculated per kg of the baked food.

[0051] And / or, based on the baked food product, the content of γ-nonanolactone in the ester flavoring substances is 110-140 μg / kg;

[0052] And / or, per kg of the baked food, the content of acetoin in the ketone flavoring substances is 3500-3700 μg / kg, and / or the content of ethylcyclopentenolone is 28-32 μg / kg;

[0053] And / or, based on per kg of the baked food, the content of n-pentanal in the aldehyde flavoring substance is 2800-3100 μg / kg;

[0054] And / or, the maltol content in the phenolic flavoring substances is 650-690 μg / kg per kg of the baked food.

[0055] Technical solution 19: The application according to any one of technical solutions 13-18 is characterized in that the application in food preparation includes the application in the preparation of fermented food;

[0056] Preferably, fermented foods include fermented fruit and vegetable juices, fermented fruits and vegetables, and / or fermented milk;

[0057] Further preferred fermented fruits and vegetables include kimchi.

[0058] Technical solution 20: The application according to any one of technical solutions 13-19 is characterized in that the application in the preparation of pharmaceuticals includes the application in fermented Chinese medicinal materials.

[0059] Technical Solution 21: A type of bread, characterized in that the leavening agent of the bread contains *Saccharomyces cerevisiae* as described in any one of claims 1-7, or the inoculum as described in technical solution 8 or 9, or the fermentation product as described in technical solution 10, or the fermentation product prepared by the method described in technical solution 11 or 12.

[0060] Technical solution 22: The bread according to technical solution 21 is characterized in that the leavening agent used in making the bread also includes brewer's yeast.

[0061] The beneficial effects of this invention include:

[0062] The *Monosporium serrulatum* AMCC 31719 strain provided in this invention can utilize multiple carbon sources during its growth, exhibiting high glycerol and β-glucosidase production, and possesses the ability to produce aroma compounds during fermentation. These aroma compounds include alcohols, esters, aldehydes, and ketones. Specifically, the alcohols include linalool (33-38 μg / L), isoamyl alcohol (12000-12400 μg / L), phenethyl alcohol (13100-13500 μg / L), and nerol (1000-1210 μg / L). The aroma activity values ​​are 150-170 for linalool, 22-26 for isoamyl alcohol, 20-25 for phenethyl alcohol, and 10-13 for nerol. Esters include isoamyl acetate at concentrations of 26-30 μg / L, phenethyl acetate at concentrations of 24000-24200 μg / L, and ethyl decanoate at concentrations of 100-130 μg / L. Isoamyl acetate has an aroma activity value of 160-190, phenethyl acetate has an aroma activity value of 90-100, and ethyl decanoate has an aroma activity value of 20-25. Aldehydes include nonanal at concentrations of 14-18 μg / L and phenylacetaldehyde at concentrations of 17-21 μg / L. Nonanal has an aroma activity value of 13-15, and phenylacetaldehyde has an aroma activity value of 3-5. Ketones include acetoin at a concentration of 350-400 μg / L. Acetonitrile has an aroma activity value of 24-28.

[0063] The *Saccharomyces cerevisiae* AMCC 31719 strain provided in this invention can delay bread staling and enhance aroma in baking applications, reducing the amount of additives used in bread processing. It can promote the production of alcohols, esters, ketones, aldehydes, and phenols in baked goods. Among these, the alcohol flavor compounds include n-hexanol at a content of 3500-3800 μg / kg, isoamyl alcohol at a content of 4000-4300 μg / kg, and phenylethanol at a content of 4500-4900 μg / kg. The aroma activity values ​​of n-hexanol and isoamyl alcohol are 70-80, 8-10, and 8-10, respectively. The ester flavor compounds include γ-nonalactone at a content of 110-140 μg / kg. The aroma activity value of γ-nonalactone is 10-15. Ketone flavor compounds include acetoin at a concentration of 3500-3700 μg / kg and ethylcyclopentenolone at a concentration of 28-32 μg / kg. Acetoniin has an aroma activity value of 240-260, and ethylcyclopentenolone has an aroma activity value of 1-3. Aldehydes flavor compounds include n-pentanal at a concentration of 2800-3100 μg / kg. N-pentanal has an aroma activity value of 240-260. Phenolic flavor compounds include maltol at a concentration of 650-690 μg / kg. Maltol has an aroma activity value of 2-5.

[0064] The *Saccharomyces cerevisiae* AMCC 31719 strain can improve bread softness and delay staling without the addition of sugar or oil, solely through the moisturizing components produced during yeast fermentation. For the food manufacturing industry, this means reducing the use of additives, lowering the calorie and fat content of products, and meeting consumers' demand for healthy eating. *Saccharomyces cerevisiae* AMCC 31719 strain can be widely used in the production of various foods, such as bread, pastries, and biscuits, and has broad market demand and promising application prospects.

[0065] Information on strain preservation

[0066] The Monosporozyma servazzii AMCC 31719 strain provided by this invention was deposited at the China Center for Type Culture Collection (CCTCC) on September 24, 2024, with accession number CCTCC NO: M20242063. The deposit address is: Wuhan University, Wuhan, China, Postcode: 430072; Telephone: 027-68754052.

[0067] The *Saccharomyces cerevisiae* AMCC 31194 used in this invention embodiment was deposited on December 29, 2021, at the China Center for Type Culture Collection (CCTCC), accession number: CCTCC NO: M 20211684, address: Wuhan University, Wuhan, China, postal code: 430072; telephone: 027-68754052. The *Saccharomyces cerevisiae* AMCC 31194 is described in patent application publication number CN117165456A. Attached Figure Description

[0068] Figure 1 shows the colony morphology of *Saccharomyces cerevisiae* strain AMCC 31719 on YPD solid medium in Example 1.

[0069] Figure 2 shows the cell morphology of the *Monosporium serrulatum* strain AMCC 31719 in Example 1.

[0070] Figure 3 shows the growth curves of *Saccharomyces cerevisiae* strain AMCC 31719 in different carbon source assimilation media in Example 2.

[0071] Figure 4 shows the growth curve of *Saccharomyces cerevisiae* strain AMCC 31719 in YPD medium in Example 2.

[0072] Figure 5 shows the phenotypes of *Saccharomyces cerevisiae* strain AMCC 31719 and *Saccharomyces cerevisiae* strain AMCC 31194 in β-glucosidase selection medium plates in Example 4.

[0073] Figure 6 shows infrared scan images of the surface and cross-section of the control group toast and the experimental group toast in Experiment Example 1. A is an infrared scan image of the surface of the control group toast, B is an infrared scan image of the surface of the experimental group toast, C is an infrared scan image of the cross-section of the control group toast, and D is an infrared scan image of the surface of the experimental group toast.

[0074] Figure 7 shows the changes in hardness of the control group and the experimental group of toast during storage in Experiment Example 1. Detailed Implementation

[0075] The technical solutions of the present invention will be further described in detail below with reference to specific embodiments and accompanying drawings, but the present invention is not limited to the following technical solutions.

[0076] The *Monosporozyma servazzii* strain provided in this invention was isolated from kimchi in Yanji City, Jilin Province, and identified as a wild-type microorganism. This strain is named *Monosporozyma servazzii* AMCC 31719. The *Monosporozyma servazzii* strain provided in this invention exhibits multi-carbon source utilization, high glycerol production, and produces a wide variety of flavor compounds after fermentation. Further research revealed that the strain possesses the ability to produce β-glucosidase. Applying this *Monosporozyma servazzii* AMCC 31719 strain to the preparation of baked goods overcomes the tendency of baked goods to stale, enhances their aroma, and provides a cleaner baking formula.

[0077] The *Saccharomyces cerevisiae* strain AMCC 31194 in Example 3 of this invention was obtained through hybridization. The specific construction and identification methods of the strain have been disclosed in patent application CN117165456A. ​​The identification results of this strain are as follows: the colony texture of this *Saccharomyces cerevisiae* strain is cheese-like, milky white in color, smooth on the surface, with neat edges, and an elliptical microscopic morphology. It reproduces by budding. 26S rDNA gene identification confirmed that this strain is a *Saccharomyces cerevisiae* strain. This strain was deposited on December 29, 2021, at the China Center for Type Culture Collection (CCTCC), accession number CCTCC NO: M20211684, address: Wuhan University, Wuhan, China, postal code: 430072; telephone: (027) 68754562.

[0078] In some specific embodiments, the raw materials used in preparing the culture medium include yeast extract and tryptone. The yeast extract primarily exists in the culture medium as an organic nitrogen source, providing the necessary nitrogen for microbial growth during fermentation. Common organic nitrogen sources such as yeast extract decompose in the culture medium, releasing amino acids and small peptides, which then become the nitrogen source required for microbial growth.

[0079] It should be noted that when using peptone as a common organic nitrogen source to prepare culture media in this invention, there are no particular limitations on its source. It can be any commercially available peptone or prepared using conventional methods. Preferably, commercially available peptone with a total nitrogen content of ≥10.0 wt% and an amino nitrogen content of ≥5.0 wt% can be used in this invention.

[0080] It should be noted that when using yeast extract powder as a common organic nitrogen source to prepare culture medium in this invention, there are no particular limitations on its source. It can be any commercially available yeast extract powder or prepared using conventional methods. Preferably, any commercially available yeast extract powder with a total nitrogen content of ≥12.5 wt%, an amino nitrogen content of ≥2.5 wt%, and a peptone content of ≥30.0 ​​wt% can be used in this invention.

[0081] Preferably, in some specific embodiments, based on the weight of the yeast extract, the yeast extract further comprises: 2-5 ppm of vitamin B1, 37-40 ppm of vitamin B2, 113-116 ppm of vitamin B5, 15-20 ppm of vitamin B6, 6-10 ppm of vitamin B7, 25-28 ppm of vitamin B9, 3205-3210 ppm of choline, 1575-1580 ppm of inositol, 325-330 ppm of niacin, and 0.2-0.4 ug of vitamin B12 per 100g of yeast extract.

[0082] And / or, by weight of the yeast extract, the content of potassium is 31910-31912 mg / kg, sodium is 5735-5740 mg / kg, calcium is 354-357 mg / kg, magnesium is 2670-2675 mg / kg, zinc is 77-83 mg / kg and iron is 77-83 mg / kg.

[0083] And / or, based on the weight of the yeast extract, the yeast extract comprises: 30.3-40.85% free amino acids and 51-70.5% hydrolyzed amino acids.

[0084] The free amino acid content includes, based on the weight of the yeast extract, 1-2% free aspartic acid, 2-3% free threonine, 1.5-2% free serine, 6.5-7% free glutamic acid, 1-1.5% free glycine, 4-5% free alanine, 0.1-0.15% free cysteine, 2-3% free valine, 0.5-1% free methionine, 2-2.5% free isoleucine, 3.3-3.7% free leucine, 0.5-1% free tyrosine, 1.5-2% free phenylalanine, 2-2.5% free lysine, 0.1-1% free histidine, 1.5-2.5% free arginine, and 0.5-1% free proline.

[0085] The hydrolyzed amino acid content includes, based on the weight of the yeast extract, 6-6.5% hydrolyzed aspartic acid, 2-3% hydrolyzed threonine, 2-3% hydrolyzed serine, 10-15% hydrolyzed glutamic acid, 2-3% hydrolyzed glycine, 5-6% hydrolyzed alanine, 0.5-1% hydrolyzed cysteine, 3-4% hydrolyzed valine, 0.5-1% hydrolyzed methionine, 3-4% hydrolyzed isoleucine, 4-5% hydrolyzed leucine, 1-2% hydrolyzed tyrosine, 2-3% hydrolyzed phenylalanine, 4-5% hydrolyzed lysine, 1-2% hydrolyzed histidine, 3-4% hydrolyzed arginine, and 2-3% hydrolyzed proline.

[0086] In some specific embodiments, the present invention provides a carbon source assimilation culture medium comprising 0.65-0.7 parts of YNB medium and 1-5 parts of carbon source. Preferably, the carbon source comprises one or more substances selected from the group consisting of glucose, galactose, lactose, sucrose, xylose, raffinose, melibiose, maltose, rhamnose, cellobiose, arabinose, inulin, stachyose, melitriose, trehalose, glycerol, lactic acid, acetic acid, fructose, and sorbitol.

[0087] Preferably, the YNB culture medium comprises: 4900-5100 parts ammonium sulfate, 1-3 parts inositol, 0.2-0.5 parts nicotinic acid, 0.2-0.5 parts thiamine hydrochloride, 0.02-0.05 parts copper sulfate, 950-1050 parts potassium dihydrogen phosphate, 0.4-0.6 parts boric acid, 0.3-0.5 parts pyridoxine hydrochloride, 0.3-0.5 parts calcium pantothenate, and 0.3-0.5 parts para-aminobenzoic acid. The ingredients are: magnesium sulfate 490-510 parts, manganese sulfate 0.3-0.5 parts, zinc sulfate 0.3-0.5 parts, ferric chloride 0.1-0.3 parts, riboflavin 0.1-0.3 parts, calcium chloride 95-105 parts, potassium iodide 0.05-0.15 parts, sodium molybdate 0.1-0.3 parts, biotin 0.001-0.003 parts, folic acid 0.001-0.003 parts, and sodium chloride 95-105 parts.

[0088] More preferably, after mixing YNB culture medium with water and bringing the volume to 1L, the nutrient composition per L comprises: ammonium sulfate 4900-5100mg, inositol 1-3mg, nicotinic acid 0.2-0.5mg, thiamine hydrochloride 0.2-0.5mg, copper sulfate 0.02-0.05mg, potassium dihydrogen phosphate 950-1050mg, boric acid 0.4-0.6mg, pyridoxine hydrochloride 0.3-0.5mg, calcium pantothenate 0.3-0.5mg, and para-amino... Benzoic acid 0.3-0.5mg, magnesium sulfate 490-510mg, manganese sulfate 0.3-0.5mg, zinc sulfate 0.3-0.5mg, ferric chloride 0.1-0.3mg, riboflavin 0.1-0.3mg, calcium chloride 95-105mg, potassium iodide 0.05-0.15mg, sodium molybdate 0.1-0.3mg, biotin 0.001-0.003mg, folic acid 0.001-0.003mg, and sodium chloride 95-105mg.

[0089] Unless otherwise stated, all reagents and instruments used in the embodiments and comparative examples of this invention are conventional commercially available products. Information on the reagents and instruments used in this invention is provided in Tables 1 and 2 below.

[0090] Table 1 Reagent Information Table

[0091] Table 2 Instrument Information Table

[0092] 1. The trace elements contained in the yeast extract powder (model: FM888) used in the examples are as follows: Vitamin B1 2.3 ppm, Vitamin B2 38.8 ppm, Vitamin B5 115.0 ppm, Vitamin B6 18.0 ppm, Vitamin B7 7.9 ppm, Vitamin B9 26.7 ppm, Vitamin B12 0.23 (ug / 100g), Choline 3206.0 ppm, Inositol 1577.7 ppm and Niacin 328.0 ppm.

[0093] The trace elements contained in the yeast extract powder (model: FM888) used in the examples are as follows: potassium 31911.66 mg / kg, sodium 5738.91 mg / kg, calcium 355.25 mg / kg, magnesium 2673.59 mg / kg, zinc 80.94 mg / kg and iron 80.21 mg / kg.

[0094] The yeast extract (model: FM888) used in the examples contained 35.1% free amino acids.

[0095] And hydrolyzed amino acids 61.21%.

[0096] The free amino acid content is as follows, based on the weight of the yeast extract: free aspartic acid 1.6%, free threonine 2.1%, free serine 1.7%, free glutamic acid 6.7%, free glycine 1.2%, free alanine 4.2%, free cysteine ​​0.1%, free valine 2.7%, free methionine 0.8%, free isoleucine 2.2%, free leucine 3.5%, free tyrosine 0.9%, free phenylalanine 1.8%, free lysine 2.3%, free histidine 0.5%, free arginine 2.0%, and free proline 0.8%.

[0097] The hydrolyzed amino acid content is as follows: based on the weight of the yeast extract, hydrolyzed aspartic acid 6.23%, hydrolyzed threonine 2.71%, hydrolyzed serine 2.73%, hydrolyzed glutamic acid 12.33%, hydrolyzed glycine 2.74%, hydrolyzed alanine 5.17%, hydrolyzed cysteine ​​0.61%, hydrolyzed valine 3.84%, hydrolyzed methionine 0.84%, hydrolyzed isoleucine 3.65%, hydrolyzed leucine 4.72%, hydrolyzed tyrosine 1.65%, hydrolyzed phenylalanine 2.68%, hydrolyzed lysine 4.63%, hydrolyzed histidine 1.19%, hydrolyzed arginine 3.30%, and hydrolyzed proline 2.19%.

[0098] 2. The preparation of the culture medium used in the examples is as follows:

[0099] YPD solid medium: 1g yeast extract FM888, 2g glucose, 2g peptone FP316, 2g agar, 100mL distilled water, sterilized at 115℃ for 20min.

[0100] YPD liquid culture medium: 1g yeast extract FM888, 2g glucose, 2g peptone, 100mL distilled water, sterilized at 115℃ for 20min.

[0101] Carbon source assimilation media: 0.67g of YNB medium and 2g of carbon source (glucose, galactose, lactose, sucrose, xylose, raffinose, melibiose, maltose, rhamnose, cellobiose, arabinose, inulin, stachyose, melitriose, trehalose, glycerol, lactic acid, acetic acid, fructose, or sorbitol) were dissolved in 100mL of sterile distilled water and then sterilized by filtering through a 0.22μm filter membrane. A total of 20 different carbon source assimilation media were prepared.

[0102] β-glucosidase screening medium: 0.1g aescin, 0.25g ferric ammonium citrate, 1g yeast extract FM888, 2g glucose, 2g peptone FP316, 100mL distilled water, sterilized at 115℃ for 20min.

[0103] Example 1: Isolation and identification of *Saccharomyces cerevisiae* strain AMCC 31719

[0104] 1. Strains Isolation and Purification

[0105] The *Monosporium serosa* AMCC 31719 strain was isolated from kimchi in Yanji City, Jilin Province. The specific isolation and purification methods are as follows:

[0106] Take 30 mL of sterile physiological saline and place it in a 50 mL sterile centrifuge tube. Use sterile forceps to scrape off about 1 g of kimchi from the surface and place it in the tube. Tighten the cap, shake for 2 minutes to mix, and take 1 mL of the mixture. Inoculate this mixture into a 50 mL centrifuge tube containing 40 mL of YPD medium and incubate at 30 °C for 48 h. Use an inoculation loop to take one loopful of the enriched bacterial solution and streak it on YPD solid medium. After single colonies grow, pick a single colony and streak it twice more on YPD solid medium for purification. Since only one colony morphology was found during the operation, after two purifications, pick a single colony and inoculate it into YPD liquid medium and incubate overnight at 30 °C for the preparation of glycerol seed and genomic extraction.

[0107] 2. Identification of strains

[0108] ITS gene sequence identification of the strain: DNA was extracted using a DNA extraction kit. Then, the strain's gene was amplified using primers ITS1 (5'-TCCGTAGGTGAACCTGCGG-3') (SEQ ID NO.1) and ITS4 (5'-TCCTCCGCTTATTGATATGC-3') (SEQ ID NO.2). The amplification conditions were as follows: PCR program: 94℃ pre-denaturation for 5 min, 94℃ denaturation for 30 s, 55℃ annealing for 15 s, 72℃ extension for 10 s, 30 cycles, and a final extension at 72℃ for 10 min. This was used to amplify the ITS gene sequence. After detection by 1% (1g / 100mL) gel electrophoresis and sequencing, the ITS gene sequence of this strain, SEQ ID NO.3, was determined as follows:

[0109] Blast analysis of the sequence with GenBank showed a sequence similarity greater than 99%, indicating the same species. Morphological analysis revealed a milky-white, cheese-like colony with a smooth surface and regular edges (Figure 1), and the cells were elliptical in shape (Figure 2). Based on morphological analysis and molecular identification, the strain was identified as *Monosporozyma servazzii*, strain number AMCC 31719. It was deposited at the China Center for Type Culture Collection (CCTCC) on September 24, 2024, with accession number CCTCC NO: M20242063.

[0110] Example 2: Carbon source assimilation test and growth curve analysis of *Saccharomyces cerevisiae* strain AMCC 31719

[0111] (1) Carbon source assimilation test

[0112] The *Saccharomyces cerevisiae* AMCC 31719 bacterial suspension preserved in glycerol tubes in Example 1 was inoculated into YPD liquid medium at a 2% (v / v) inoculation rate and activated overnight. 1 mL of the bacterial suspension was transferred to a 2 mL EP tube, centrifuged at 8000 rpm for 3 min, the supernatant was discarded, and the suspension was resuspended in 1 mL of sterile water to wash away residual sugars. The suspension was centrifuged again at 8000 rpm for 3 min, the supernatant was discarded, and the bacterial cells were resuspended in 1 mL of sterile water. 2 μL of the bacterial suspension was inoculated into 20 different ELISA plates containing 200 μL of carbon source assimilation medium, and incubated at 30°C and 180 rpm for 72 h. Turbidity was observed. ， The more bacteria accumulate and the more turbid the environment becomes, the higher its carbon source utilization rate. "+" and "-" represent carbon source utilization, respectively. Strong positive: "+++", positive: "++", weak positive: "+", negative: "-". The results are shown in Table 3.

[0113] Table 3

[0114] Table 3 shows that *Monosporium serosa* strain AMCC 31719 can utilize glucose, galactose, xylose, melibiose, maltose, cellobiose, inulin, stachyose, trehalose, glycerol, and fructose, but cannot utilize lactose, sucrose, raffinose, rhamnose, arabinose, mesotriose, lactic acid, acetic acid, and sorbitol. Furthermore, *Monosporium serosa* strain AMCC 31719 grows vigorously in glucose, galactose, and fructose, followed by inulin, stachyose, and maltose, and grows slowly in trehalose, glycerol, melibiose, xylose, and cellobiose.

[0115] (2) Growth curve analysis

[0116] The *Saccharomyces cerevisiae* AMCC 31719 culture preserved in glycerol tubes in Example 1 was inoculated into YPD liquid medium at a 2% (v / v) inoculation rate and cultured at 30°C and 180 rpm for 24 h to obtain a viable count of 10. 8A bacterial suspension of CFU / mL was prepared and centrifuged and washed. The specific centrifugation and washing method was as follows: 1 mL of the bacterial suspension was centrifuged at 8000 rpm for 2 min, the supernatant was discarded, and the bacterial pellet was retained. The bacterial pellet was resuspended in 1 mL of sterile water and washed twice by centrifugation. Then, the bacterial pellet was resuspended in 1 mL of sterile water and inoculated at a 1% (v / v) inoculum into 100-well plates containing 300 μL of 20 different carbon source assimilation media. Growth curves were measured and plotted using a Bioscreen C instrument. The 20 carbon source assimilation media contained the following carbon sources: glucose, galactose, lactose, sucrose, xylose, raffinose, melibiose, maltose, rhamnose, cellobiose, arabinose, inulin, stachyose, melitriose, trehalose, glycerol, lactic acid, acetic acid, fructose, and sorbitol. The Bioscreen C instrument was set to the following parameters: temperature 30℃, wavelength 600nm, absorbance measured every 0.5 hours. Figure 3 shows the growth curves of *Saccharomyces cerevisiae* AMCC 31719 in different carbon source assimilation media. As can be seen from Figure 3, *Saccharomyces cerevisiae* AMCC 31719 grew better in carbon assimilation media containing glucose, galactose, or fructose as carbon sources, exhibiting an S-shaped growth curve. During the exponential phase, the strain grew rapidly, reaching a plateau after 24 hours of culture. In media containing inulin, stachyose, or maltose as carbon sources, the exponential phase of *Saccharomyces cerevisiae* AMCC 31719 was relatively flat, with an S-shaped growth curve, and it did not reach its plateau phase after 72 hours of culture. In media containing xylose, melibiose, cellobiose, trehalose, and glycerol, the growth curves of *Saccharomyces cerevisiae* AMCC 31719 did not show a significant lag phase, exhibiting a slow and continuous growth trend within 72 hours of culture. In this study, the specific growth rate (μ) of *Saccharomyces cerevisiae* AMCC 31719 strain was calculated for each data detection time period (0.5 h) in different carbon source assimilation media as follows: (OD data at the end of In - OD data at the beginning of In) / 0.5. The maximum calculated specific growth rate (μ) was taken as the maximum specific growth rate (μ). max ), as shown in Table 4.

[0117] Table 4

[0118] As shown in Table 4, the *Monosporium serrulatum* AMCC 31719 strain exhibited the highest specific growth rate in glucose-carbon source assimilation medium, with a μ... maxThe value was 0.31, indicating that glucose was the most efficiently utilized carbon source for *Saccharomyces cerevisiae* AMCC 31719 strain. The growth curve of *Saccharomyces cerevisiae* AMCC 31719 strain in YPD medium is shown in Figure 4. In YPD medium with glucose as the carbon source, the 0-3 hour culture period was the lag phase, the 3-10 hour culture period was the exponential phase, and the plateau phase occurred after 12 hours of culture. The maximum specific growth rate μ in YPD medium was [not specified]. max The OD value during the plateau phase was 1.38, with a value of 0.55. YPD medium is richer in nutrients than carbon source assimilation medium, and can more accurately characterize the growth trend and biomass of yeast strains during conventional fermentation.

[0119] Example 3: Analysis of fermentation metabolites and flavor compounds of *Saccharomyces cerevisiae* strain AMCC 31719

[0120] (1) Fermentation metabolites of *Saccharomyces cerevisiae* strain AMCC 31719

[0121] The *Saccharomyces cerevisiae* AMCC 31719 culture preserved in glycerol tubes in Example 1 was inoculated into YPD liquid medium at a 2% (v / v) inoculation rate and activated overnight. Then, 1.5 mL of the culture was inoculated into a 500 mL shake flask containing 300 mL of YPD liquid medium and cultured at 30°C and 180 rpm for 24 h with shaking. The viable count was 3 × 10⁻⁶. 8 The fermentation broth of *Saccharomyces cerevisiae* strain AMCC 31719 (CFU / mL) was collected. After shaking well, the broth was dispensed into 50mL centrifuge tubes and centrifuged at 5000rpm for 10min. The supernatant was collected and analyzed by liquid chromatography. *Saccharomyces cerevisiae* strain AMCC 31194 was used as a control strain. The collection and analysis methods for the fermentation supernatant of *Saccharomyces cerevisiae* strain AMCC 31194 were the same as those for *Saccharomyces cerevisiae* strain AMCC 31719. The components of the fermentation supernatant of both strains are shown in Table 5.

[0122] Table 5

[0123] As shown in Table 5, the fermentation supernatant of *Monoclonus serrulatus* strain AMCC 31719 (fermentation product of *Monoclonus serrulatus*) contained lactic acid content greater than or equal to 659.90 μg / mL, maltose monohydrate content greater than or equal to 1330.90 μg / mL, fructose content greater than or equal to 864.80 μg / mL, succinic acid content greater than or equal to 1748.20 μg / mL, and ethanol content greater than or equal to 43115.30 μg / mL. Specifically, the lactic acid content was 659.90-794.10 μg / mL, the maltose monohydrate content was 1330.90-1365.00 μg / mL, the fructose content was 864.80-1101.00 μg / mL, the succinic acid content was 1748.20-1816.50 μg / mL, and the ethanol content was 43115.30-43191.50 μg / mL.

[0124] Table 5 also shows that, compared with Saccharomyces cerevisiae, the fermentation metabolites of Saccharomyces cerevisiae AMCC 31719 strain during the shake-flask culture stage mainly showed a high glycerol production of 7532.40-7699.10 μg / mL, approximately 7.5-7.7 g / L. Since the sweetness threshold of glycerol is 5.2 g / L, as shown in Table 5, the glycerol production in the fermentation supernatant of Saccharomyces cerevisiae AMCC 31194 strain was 2467.80-2591.50 μg / mL, approximately 2.47-2.59 g / L, which did not reach the sweetness threshold of 5.2 g / L. Its glycerol production was only 33% of that of Saccharomyces cerevisiae AMCC 31719 strain. Because glycerol is hygroscopic, odorless, and has a sweet taste similar to glucose, it is commonly used in the food processing industry as a sweetener and humectant. It gives food a smooth and delicious texture and better sensory qualities. In bread and cakes, it is used as a moisture-retaining agent because it has strong hygroscopic properties, which can keep bread soft and extend its shelf life.

[0125] (2) Volatile fermentation flavor compounds of Saccharomyces cerevisiae AMCC 31719 strain

[0126] Take 5 mL of *Saccharomyces cerevisiae* AMCC 31719 fermentation supernatant into a headspace vial, add 1.5 g sodium chloride and 1 μL internal standard (o-dichlorobenzene), mix well, equilibrate at 50 °C for 30 min, and perform full-scan detection and analysis of volatile components. Gas chromatography conditions: column: DB-HeavyWAX, 30 m × 0.25 mm × 0.25 μm, injection port temperature: 250 °C, carrier gas: He; temperature program: 40 °C for 3 min, ramp to 200 °C at a rate of 5 °C / min, hold for 0 min; ramp to 250 °C at a rate of 10 °C / min, hold for 3 min. Aroma components were qualitatively identified using scanning mode. The NIST 17 standard library was searched using chromatographic retention time and mass spectrometry information. Volatile substance concentration was calculated based on peak area: Volatile substance concentration (μg / L) = (Volatile substance peak area (mAU*min) / Internal standard peak area (mAU*min)) * (Internal standard concentration (μg / L) * Internal standard volume (mL) / Sample volume (mL)). Aroma activity values ​​were calculated for different volatile substances, and volatile components with an aroma activity value greater than 1 were selected for aroma characteristic analysis. The aroma activity value calculation formula is as follows: Aroma activity value = Volatile substance concentration (μg / L) / Aroma component threshold (μg / L). The aroma component threshold was obtained from the book "Compilation of Compound Olfactory Thresholds". Table 6 shows the volatile flavor compounds with an aroma activity value greater than 1 in the fermentation supernatant of *Saccharomyces cerevisiae* strain AMCC 31719.

[0127] Table 6

[0128] Table 6 shows that the fermentation supernatant of *Saccharomyces cerevisiae* strain AMCC 31719 contained 10 core volatile flavor compounds (aroma activity values ​​greater than 1), including 4 alcohols, 3 esters, 2 aldehydes, and 1 ketone. Among the alcohols, linalool was the main aroma contributor, with a relative content of approximately 35.28 μg / L and an aroma activity value of 160.82, primarily contributing to the lily-of-the-valley aroma. Among the esters, isoamyl acetate mainly contributed to the banana aroma (aroma activity value 189.73), phenethyl acetate contributed to the peach aroma (aroma activity value 96.56), and ethyl decanoate contributed to the coconut aroma (aroma activity value 22.84). Among the aldehydes, nonanal mainly contributed to the sweet orange and oily aromas (aroma activity value 14.68), and phenylacetaldehyde mainly contributed to the daffodil aroma (aroma activity value 4.96). Acetylene, a ketone compound, primarily contributes to the aroma of milk, with an aroma activity value of 26.81.

[0129] Example 4: Enzyme production performance of *Saccharomyces cerevisiae* strain AMCC 31719

[0130] The *Saccharomyces cerevisiae* AMCC 31719 and *Saccharomyces cerevisiae* AMCC 31194 bacterial cultures, preserved in glycerol tubes, were inoculated into YPD liquid medium at a 2% (v / v) inoculation rate and activated overnight. β-glucosidase selection medium was poured onto plates, and 2 μL of the overnight-cultured *Saccharomyces cerevisiae* AMCC 31719 and *Saccharomyces cerevisiae* AMCC 31194 bacterial cultures were spot-inoculated at the center of the plates containing β-glucosidase selection medium. The plates were incubated upside down at 30°C, and this process was repeated three times. Observations showed that *Saccharomyces cerevisiae* AMCC 31719 strain began to show black hydrolysis zones around colonies after 4 hours of culture, and these zones gradually deepened after 6 hours. In contrast, *Saccharomyces cerevisiae* AMCC 31194 did not show an enzyme-producing phenotype after 6 hours of culture. As shown in Figure 5, after 20 hours of cultivation, the black hydrolysis zone of the *Saccharomyces cerevisiae* strain AMCC 31719 on the left side of Figure 5 was significantly larger and deeper in color than that of the *Saccharomyces cerevisiae* strain AMCC 31194 on the right side. At this time, the colony diameter of *Saccharomyces cerevisiae* strain AMCC 31719 was d = 0.80 cm, the diameter of the black hydrolysis zone was D = 3.15 cm, and D / d = 3.94; at the same time, the colony diameter of *Saccharomyces cerevisiae* strain AMCC 31194 was d = 0.81 cm, the diameter of the black hydrolysis zone was D = 1.5 cm, and D / d = 1.85. The size and depth of the black hydrolysis zone on the β-glucosidase-producing plate can qualitatively indicate the β-glucosidase production characteristics of the strain. Since the D / d ratio of *Monosporium sericeum* AMCC 31719 is 113% higher than that of *Saccharomyces cerevisiae* AMCC 31194, and the enzyme-producing phenotype of *Monosporium sericeum* AMCC 31719 appears earlier, it indicates that *Monosporium sericeum* AMCC 31719 has a stronger β-glucosidase production capacity. Because esculin and ferric ammonium citrate were added to the β-glucosidase selection medium, when esculin decomposes into esculin, esculin reacts with the ferrous ions in ferric ammonium citrate to form a black compound, turning the medium black. Aesculin and cellobiose, among other glycosides, have similar β-D-glucanose structures, and β-glucosidase can decompose cellobiose structures in the enzymatic reaction, thus recognizing and binding esculin to decompose it into esculin.

[0131] Experimental Example 5: Baking Application of Saccharomyces cerevisiae AMCC 31719

[0132] Saccharomyces cerevisiae AMCC 31194 was used as the control strain, and Saccharomyces cerevisiae AMCC 31719 was used as the test strain. Glycerol cultures of both strains were streaked on YPD solid medium plates for 48 h. A loopful was then inoculated into a test tube containing 5 mL of YPD liquid medium. After overnight incubation, the culture was transferred at 0.5% (v / v) to a shake flask containing YPD liquid medium. The mixture was then incubated at 30°C and 180 rpm for 24 h, centrifuged at 5000 rpm for 10 min, and the fermentation supernatant was discarded. Yeast milk samples from Saccharomyces cerevisiae AMCC 31194 and Saccharomyces cerevisiae AMCC 31719 were collected. Prepare the starter dough according to the recipe in Table 7. First, weigh out the yeast milk. For the control group, weigh out 6g of brewer's yeast AMCC 31194 yeast milk, and for the experimental group, weigh out 2g of brewer's yeast AMCC 31194 yeast milk and 4g of yeast milk from Monosporus cerevisiae AMCC 31719. Add 100g of water and mix thoroughly, then add 100g of high-gluten flour. Stir briefly until there is no dry flour, cover with plastic wrap, and ferment at 30℃ for 2 hours until the starter dough doubles in size. Then transfer to 4℃ and refrigerate overnight for 14 hours. Next, pour the starter dough from both the control group and the experimental group into a dough mixer according to the main dough recipe in Table 7. Set the mixing program to automatically stop mixing when the dough temperature reaches 26℃. Remove the dough, divide it into 400g portions, and label them 1-3. After manually shaping, let them rest for 4 minutes, then roll them into loaf rolls using an automatic shaping machine. Place them in a loaf pan and proof at 38℃ until the dough reaches the top of the loaf pan.

[0133] Table 7

[0134] Both the control group and the experimental group, with dough balls (numbers 1-3) fully risen into the loaf pan, were placed in a preheated oven. The baking temperature was set to 210℃ (top) and 230℃ (bottom) for 25 minutes. After baking, the dough was unmolded and allowed to cool. An infrared scanner was then used to fully scan and record the appearance of the loaf. The surfaces of the control group and the experimental group loaf are shown in Figures 6A and 6B, respectively. The control group loaf showed a slight, visibly collapsed waist. The cross-sectional images of the control group and the experimental group loaf are shown in Figures 6B and 6C, respectively. The experimental group loaf had a smooth, even shape. The control group and the experimental group's No. 1 toast were then sliced ​​using a slicing machine. The air holes in the three center slices of No. 1 toast were selected, and the unevenness and indentation of the air holes were analyzed using a C-cell instrument. The analysis showed that the experimental group had a more uniform air hole distribution. The unevenness of air holes in the experimental group was 3.77%, while that in the control group was 8.16%, a reduction of 53.80%. The indentation of the control group toast was 3.20%, while that in the experimental group toast was 2.23%, resulting in a 30.31% improvement in the product appearance of the experimental group toast. The results are shown in Table 8.

[0135] Table 8

[0136] Since an increase in bread hardness is an important indicator of bread aging, the cooled loaves of bread No. 2 and No. 3 from the control group and the experimental group were placed in plastic bags and stored at room temperature. After 1 day and 4 days of storage, the loaves were sliced, and the six center slices were selected. Two slices were stacked together to form a group, and the whole texture was tested using a texture analyzer. The degree of aging was compared by detecting the change in the hardness of the bread. The test parameters were: strain 50%, probe return speed 20 mm / sec, and contact force 5 g. The test results are shown in Figure 7. On the day of baking, the hardness of the control group toast was 170.68±4.62g, and the hardness of the experimental group toast was 169.12±17.30g. There was no significant difference in hardness between the two groups (p>0.05). After one day of storage at room temperature, the toast began to age. At this time, the hardness of the control group toast was 313.29±12.83g, and the hardness of the experimental group toast was 261.53±9.93g. The aging of the experimental group toast was significantly delayed by 16.52% compared with the control group (p<0.05). After four days of storage at room temperature, both the experimental and control group toasts were still soft to the touch, odorless, and mold-free. The experimental group toast had a buttery aroma. The hardness of the control group toast was 491.80±18.63g, and the hardness of the experimental group toast was 419.68±21.70g. The aging of the experimental group toast was still significantly delayed by 14.66% compared with the control group (p<0.05).

[0137] Accurately weigh 5g of bread crumbs from both the control and experimental groups into solid-phase extraction headspace vials, add 1μL of internal standard solution (o-dichlorobenzene), mix well, and seal the vials. Equilibrate at 50℃ for 30 min, then perform GC-MS analysis. Gas chromatography conditions: column: DB-HeavyWAX, 30m×0.25mm×0.25μm, injection port temperature: 250℃, carrier gas: He; temperature program: 40℃ for 3 min, ramp to 200℃ at a rate of 5℃ / min, hold for 0 min; ramp to 250℃ at a rate of 10℃ / min, hold for 3 min. The concentration of volatile substances was calculated based on the peak area. The volatile substance concentration (μg / L) was calculated as follows: (volatile substance peak area (mAU*min) / internal standard peak area (mAU*min)) * (internal standard concentration (μg / L) * internal standard volume (mL) / sample volume (mL)). Furthermore, the aroma activity values ​​of different volatile substances were calculated, and volatile components with aroma activity values ​​greater than 1 were selected for aroma characteristic analysis. The aroma activity value calculation formula is as follows: Aroma activity value = volatile substance concentration (μg / L) / aroma component threshold (μg / L). The aroma component threshold was obtained from the book "Compilation of Compound Olfactory Thresholds". The effects of *Saccharomyces cerevisiae* AMCC 31194 in the control group toast and *Saccharomyces cerevisiae* AMCC 31719 in the experimental group toast on the volatile flavor compounds in the toast were analyzed using GC-MS full-scan detection. The results are shown in Table 9.

[0138] Table 9

[0139] As shown in Table 9, five core flavor compounds were detected in the control group toast, while eight were detected in the experimental group toast. Hexanol, γ-nonanolide, and ethylcyclopentenolone were unique flavor compounds found only in the experimental group toast. Hexanol's aroma is characterized by fat and fruitiness, primarily used to create coconut and berry aromas. γ-nonanolide's aroma is characterized by coconut and cream, while ethylcyclopentenolone's aroma is similar to caramel, smoke, and coffee. Comparing the relative contents, among the flavor compounds shared by both groups, the experimental group toast contained significantly higher levels of phenylethyl alcohol, acetoin, n-pentanal, and maltol than the control group. Further comparison of the aroma activity values ​​of the two groups revealed that the substance with the highest aroma activity value in the control group toast was n-pentanal, characterized by a fermented bread aroma, with an aroma activity value of 70.97. In the experimental group toast, the substance with the highest aroma activity value was acetoin, characterized by a milky aroma, with an aroma activity value of 259.21, representing a 378.60% increase compared to the control group. Furthermore, the aroma activity values ​​of phenylethanol, isoamyl alcohol, and maltol in the experimental group were all more than three times higher than those in the control group. In summary, the contributions of substances such as acetoin, n-hexanol, and γ-nonanolide in the experimental group added a greater milky aroma to the toast. Therefore, the *Saccharomyces cerevisiae* AMCC 31719 strain can delay toast staling and enhance the milky aroma of toast in applications. Monosporum serrulatum AMCC 31719 can improve softness and delay bread staling solely through the moisturizing components produced during yeast fermentation, without the addition of sugar and oil. For the food manufacturing industry, this can reduce the use of additives, lower the calorie and fat content of products, and meet consumers' demand for healthy eating.

[0140] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A Yarrowia lipolytica, characterized in that, The Monosporozer vazzii is the AMCC 31719 strain of Monosporozer vazzii, which is preserved in the China Center for Type Culture Collection (CCTCC) with the preservation number of CCTCC NO: M 20242063.

2. The Yarrowia lipolytica of claim 1, wherein, The ITS gene sequence of the Monosporozer vazzii AMCC 31719 strain is shown in SEQ ID NO.

3.

3. The Yarrowia lipolytica of claim 1 or 2, characterized in that, The carbon sources that can be utilized by the Monosporozer vazzii AMCC 31719 strain include one or more than two selected from the group consisting of glucose, galactose, xylose, melibiose, maltose, cellobiose, inulin, stachyose, trehalose, glycerol and fructose.

4. The Yarrowia lipolytica of any one of claims 1-3, wherein, The Monosporozer vazzii AMCC 31719 strain produces glycerol. Preferably, the content of glycerol in the fermentation broth of the Monosporozer vazzii is ≥ 7.5 g / L. Further preferably, the content of glycerol in the fermentation broth of the Monosporozer vazzii is 7.5-7.7 g / L.

5. The Yarrowia lipolytica of any one of claims 1-4, wherein, The Monosporozer vazzii AMCC 31719 strain produces β-glucosidase.

6. The Yarrowia lipolytica of any one of claims 1-5, wherein, The Monosporozer vazzii AMCC 31719 strain produces flavoring substances, which include alcohols, esters, aldehydes and ketones. Preferably, the alcohols include linalool, isoamyl alcohol, phenethyl alcohol and / or nerolidol. And / or, the esters include isoamyl acetate, phenethyl acetate and / or ethyl decanoate. And / or, the aldehydes include nonanal and / or phenylacetaldehyde. And / or, the ketones include acetoin. Further preferably, the flavoring substances include acetoin.

7. The Yarrowia lipolytica of claim 6, wherein, The concentration of linalool in the alcohols is 33-38 μg / L, and / or the concentration of isoamyl alcohol is 12000-12400 μg / L, and / or the concentration of phenethyl alcohol is 13100-13500 μg / L, and / or the concentration of nerolidol is 1000-1210 μg / L. And / or, the concentration of isoamyl acetate in the esters is 26-30 μg / L, and / or the concentration of phenethyl acetate is 24000-24200 μg / L, and / or the concentration of ethyl decanoate is 100-130 μg / L. And / or, the concentration of nonanal in the aldehydes is 14-18 μg / L, and / or the concentration of phenylacetaldehyde is 17-21 μg / L. And / or, the concentration of acetoin in the ketones is 350-400 μg / L.

8. An inoculant characterized in that, The microbial agent includes the Monosporozer vazzii AMCC 31719 strain according to any one of claims 1-7.

9. The bacterial agent of claim 8, characterized in that, The microbial agent further includes excipients.

10. A fermentable material, characterized in that, The fermentation product is prepared by fermentation of the Monosporozer vazzii AMCC 31719 strain according to any one claims 1-7 or the microbial agent according to claim 8 or 9.

11. A method of producing the ferment of claim 10, characterized by, The method includes the following steps: culturing the Monosporozer vazzii AMCC 31719 strain according to any one claim 1-7 or the microbial agent according to claim 8 or 9.

12. The method of claim 11, wherein, The preparation method includes the following steps: (1) culturing the Leucosporidium sersersii AMCC 31719 strain of any one of claims 1-7 or the microbial agent of claim 8 or 9 in a large scale; (2) adding the product obtained in step (1) to a culture medium and culturing at 10-45℃.

13. Use of the Leucosporidium sersersii of any one of claims 1-7 or the microbial agent of claim 8 or 9 in the preparation of food, food additive, feed, medicine or health care product.

14. Use according to claim 13, characterized in that, The use in the preparation of food additive includes the use in the preparation of moisturizing food additive or the preparation of food flavoring.

15. Use according to claim 13 or 14, characterized in that, The use in the preparation of food includes the use in the preparation of baked food. Preferably, the baked food includes bread, cake, biscuit, steamed bun and / or stuffed bun. Further preferably, in the preparation of baked food, the Leucosporidium sersersii is used in synergistic fermentation with Saccharomyces cerevisiae.

16. The use according to claim 15, characterized in that, In the preparation of baked food, the moisture-retaining ingredient is produced in the early fermentation of baked food, delaying the aging of baked food.

17. Use according to claim 15 or 16, characterized in that, In the preparation of baked food, the flavor of baked food is improved. Preferably, the baked food contains alcohol, ester, ketone, aldehyde and / or phenolic flavoring substances. And / or, the alcohol flavoring substances include n-hexanol, isoamyl alcohol and / or phenylethanol. And / or, the ester flavoring substances include γ-nonanolactone. And / or, the ketone flavoring substances include ethyl lactate and / or ethyl cyclopentenolone. And / or, the aldehyde flavoring substances include n-pentanal. And / or, the phenolic flavoring substances include maltol.

18. The use according to claim 17, characterized in that, The content of n-hexanol in the alcohol flavoring substances is 410-430 μg / kg, and / or the content of isoamyl alcohol is 4000-4300 μg / kg, and / or the content of phenylethanol is 4700-4900 μg / kg. And / or, the content of γ-nonanolactone in the ester flavoring substances is 110-140 μg / kg. And / or, the content of ethyl lactate in the ketone flavoring substances is 3500-3700 μg / kg, and / or the content of ethyl cyclopentenolone is 28-32 μg / kg. And / or, the content of n-pentanal in the aldehyde flavoring substances is 2800-3100 μg / kg. And / or, the content of maltol in the phenolic flavoring substances is 650-690 μg / kg.

19. The use according to any one of claims 13 to 18, characterized in that, The use in the preparation of food includes the use in the preparation of fermented food. Preferably, the fermented food includes fermented fruit and vegetable juice, fermented fruit and vegetable and / or fermented milk. Further preferably, the fermented fruit and vegetable includes pickled vegetable.

20. The use according to any one of claims 13 to 19, characterized in that, The use in the preparation of medicine includes the use in the fermentation of traditional Chinese medicinal materials.

21. A bread, characterized in that The bread contains the Leucosporidium sersersii of any one of claims 1- 7 or the microbial agent of claim 8 or 9 or the fermented product prepared by the method of claim 10 or the fermented product of claim 11 or 12.

22. The bread according to claim 21, characterized in that The bread contains Saccharomyces cerevisiae as a fermenting agent.

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