Leuconostoc mesenteroides subsp. Mesenteroides and application thereof

Abstract

The invention provides a leuconostoc mesenteroides subsp. Mesenteroides and application thereof. The Leuconostoc mesenteroides subsp. Mesenteroides disclosed by the invention is preserved in China General Microbiological Culture Collection Center on September 20, 2023, and the preservation number is CGMCC No.28494. The Leuconostoc mesenteroides subsp. Mesenteroides disclosed by the invention can be used for increasing the content of acidic polysaccharide in a plant fermentation product and increasing the yield of the plant fermentation product. Therefore, the compound can be applied to preparation of related products with the functions of enhancing the body immune function, resisting tumors, resisting oxidation, reducing blood sugar and the like.

Description

Technical Field

[0001] The invention relates to the field of microorganisms, and in particular to a strain of Leuconostoc mesenteroides subspecies mesenteroides and an application thereof. Background Art

[0002] Polysaccharide is a polymeric carbohydrate composed of sugar chains linked by glycosidic bonds, at least more than 10 monosaccharides. Polysaccharide is a natural polymer compound. The complexity of its structure determines the diversity of its functions. Polysaccharides can usually be divided into neutral polysaccharides, acidic polysaccharides and alkaline polysaccharides. Among them, acidic polysaccharides refer to polysaccharides containing acidic groups such as carboxyl or sulfate. They are an important biological substance with a wide range of sources and multiple biological activities, such as antioxidant, immunomodulatory, hypoglycemic and anti-tumor activities. They have little toxicity and side effects and have great development potential.

[0003] At present, fermentation methods that use enzymes and other components secreted by microbial cells to generate or increase the content of acidic polysaccharides in plant fermentation products have become a research hotspot. However, due to the lack of existing technologies, the content of acidic polysaccharides in plant fermentation products is often low. Therefore, how to find a method that can significantly increase the content of acidic polysaccharides in plant fermentation products needs to be solved urgently. Summary of the invention

[0004] The invention provides a strain of Leuconostoc mesenteroides subsp. mesenteroides and application of the strain in improving the content of acidic polysaccharides in plant fermentation products.

[0005] The invention provides a method for increasing the content of acidic polysaccharides in plant fermentation products. The method is simple and convenient, is convenient for subsequent large-scale production, and can obtain plant fermentation products containing a large amount of acidic polysaccharides.

[0006] The present invention also provides a plant fermentation product, which contains a large amount of acidic polysaccharides and can be used to prepare related products with functions such as enhancing the body's immune function, anti-tumor, anti-oxidation, and lowering blood sugar.

[0007] The present invention provides a strain of Leuconostoc mesenteroides subsp. mesenteroides, which was deposited in the General Microbiology Center of China National Microbiological Culture Collection Administration on September 20, 2023, with a deposit number of CGMCC No. 28494.

[0008] The invention provides an application of the above-mentioned Leuconostoc mesenteroides subsp. mesenteroides in improving the content of acidic polysaccharides in plant fermentation products.

[0009] The present invention provides a method for increasing the content of acidic polysaccharides in plant fermentation products, comprising the following steps:

[0010] mixing the plant material with water to obtain a plant stock solution;

[0011] Prepare a liquid culture medium based on the plant stock solution;

[0012] The above-mentioned Leuconostoc mesenteroides subsp. mesenteroides is inoculated into a liquid culture medium for fermentation, and a plant fermentation product is obtained after the fermentation is completed.

[0013] In the method as described above, the fermentation temperature is 30-40°C, the time is 9-15 days, and the stirring speed is 100-200 r / min.

[0014] In the method as described above, the plant raw material includes at least one of Dendrobium, Ganoderma lucidum, Poria, Lilium, Lycium barbarum, Cistanche deserticola, Coix seeds, Cornus officinalis, Cordyceps sinensis, Rhodiola rosea, and Polygonatum sibiricum.

[0015] The method as described above, wherein the mass ratio of the plant material to water is 1:(5-40).

[0016] In the method as described above, the liquid culture medium comprises sugar substances, and the content of the sugar substances is 4% (m / v)-10% (m / v).

[0017] The method as described above, wherein the inoculation amount is 0.5% (v / v)-2% (v / v).

[0018] The present invention also provides a plant fermentation product, wherein the plant fermentation product is obtained by the above method.

[0019] The plant fermentation product as described above, wherein the content of acidic polysaccharides in the plant fermentation product is ≥200 mg / 100 g.

[0020] The present invention provides a strain of Leuconostoc mesenteroides subsp. mesenteroides, which was deposited in the General Microbiology Center of China National Microbiological Culture Collection Administration on September 20, 2023, with a deposit number of CGMCC No. 28494, and can increase the content of acidic polysaccharides in plant fermentation products. DETAILED DESCRIPTION

[0021] In order to enable those skilled in the art to better understand the scheme of the present invention, the present invention is further described in detail below. The specific implementation methods listed below are only for describing the principles and features of the present invention. The examples are only used to explain the present invention and are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] The first aspect of the present invention provides a strain of Leuconostoc mesenteroides subsp. mesenteroides, which was deposited in the China General Microbiology Collection Center (CGMCC) on September 20, 2023, with the deposit address at No. 3, Yard No. 1, Beichen West Road, Chaoyang District, Beijing, and the deposit number is CGMCC No. 28494.

[0023] The second aspect of the present invention provides a use of the above-mentioned Leuconostoc mesenteroides subsp. mesenteroides in increasing the content of acidic polysaccharides in plant fermentation products.

[0024] The inventors have found in long-term research that the use of the Leuconostoc mesenteroides subsp. mesenteroides provided by the present invention can increase the content of acidic polysaccharides in plant fermentation products. Since acidic polysaccharides refer to polysaccharides containing acidic groups such as carboxyl or sulfate groups, they are important biologically active polysaccharides with functions such as enhancing immunity, anti-tumor, anti-oxidation, and hypoglycemic. Therefore, the Leuconostoc mesenteroides subsp. mesenteroides provided by the present invention can also be used to prepare related products with functions such as enhancing immunity, anti-tumor, anti-oxidation, and hypoglycemic. Specifically, the related products include but are not limited to food and health products.

[0025] The third aspect of the present invention provides a method for increasing the content of acidic polysaccharides in plant fermentation products, comprising the following steps:

[0026] mixing the plant material with water to obtain a plant stock solution;

[0027] Prepare a liquid culture medium based on the plant stock solution;

[0028] The above-mentioned Leuconostoc mesenteroides subsp. mesenteroides is inoculated into a liquid culture medium for fermentation, and a plant fermentation product is obtained after the fermentation is completed.

[0029] The inventors have conducted a lot of research and exploration on how to make plant fermentation products contain more acidic polysaccharides, and proved that the above method can effectively increase the content of acidic polysaccharides. First, the plant raw material is mixed with water to obtain a plant stock solution, and then a liquid culture medium is prepared based on the plant stock solution. Subsequently, the Leuconostoc mesenteroides subsp. mesenteroides provided by the first aspect of the present invention is inoculated into the liquid culture medium and fermented. After the fermentation is completed, a plant fermentation product containing a large amount of acidic polysaccharides can be obtained. This method is simple and convenient, and is convenient for subsequent large-scale production.

[0030] Specifically, the fermentation temperature is 30-40°C, the time is 9-15 days, and the stirring speed is 100-200r / min, which helps to further increase the acidic polysaccharide content in the plant fermentation product.

[0031] It is understandable that for different plant raw materials, those skilled in the art can select appropriate fermentation treatment conditions according to the above range. For example, when the plant raw material is Dendrobium, the fermentation temperature can be 32-35°C, the time is 9 days, and the stirring speed is 100-200r / min; when the plant raw material is Ganoderma lucidum, the fermentation temperature can be 32-37°C, the time is 15 days, and the stirring speed is 100-200r / min; when the plant raw material is Poria cocos, the fermentation temperature can be 32-35°C, the time is 10 days, and the stirring speed is 100-200r / min; when the plant raw material is Lilium, the fermentation temperature can be 34-37°C, the time is 12 days, and the stirring speed is 100-200r / min.

[0032] Furthermore, the inventors found that regulating the types of plant raw materials can also help increase the content of acidic polysaccharides in plant fermentation products. Specifically, the plant raw materials can include at least one of Dendrobium, Ganoderma lucidum, Poria, Lilium, Lycium barbarum, Cistanche, Coix seeds, Cornus officinalis, Cordyceps sinensis, Rhodiola rosea, and Polygonatum sibiricum.

[0033] In the scheme of the present invention, the mass ratio of plant raw material to water is 1: (5-40), which helps to maintain good fluidity and specific surface area of ​​the obtained plant stock solution, so as to promote good contact between the subsequent liquid culture medium prepared from Leuconostoc mesenteroides subsp. mesenteroides and the plant stock solution, thereby promoting the full progress of the fermentation process. If too little water is added, the fluidity of the plant stock solution is poor, which is not conducive to the subsequent fermentation process and is likely to reduce the efficiency of the fermentation process; if too much water is added, the reaction volume is too large during the subsequent fermentation process, which increases the load of the subsequent process and wastes resources.

[0034] It is understood that for different plant raw materials, those skilled in the art can select a suitable mass ratio of plant raw materials to water according to the above range. For example, when the plant raw material is Dendrobium officinale, the mass ratio of Dendrobium officinale to water can be 1:(25-35); when the plant raw material is Ganoderma lucidum, the mass ratio of Ganoderma lucidum to water can be 1:(20-30); when the plant raw material is Poria cocos, the mass ratio of Poria cocos to water can be 1:(12-16); when the plant raw material is Lilium brevifolium, the mass ratio of Lilium brevifolium to water can be 1:(18-22).

[0035] In addition, in order to ensure sufficient mixing of the plant raw material and water, the plant raw material can be crushed by a high-speed crusher to obtain a 40-80 mesh powdered plant raw material, and then the powdered plant raw material and water are weighed separately according to a mass ratio of 1: (5-40), and the powdered plant raw material is slowly added to the water at a stirring speed of 100-500r / min to obtain a plant stock solution.

[0036] Since some plant raw materials are rich in starch, which may affect the subsequent fermentation reaction, amylase can be used for enzymatic hydrolysis. For example, the Poria cocos stock solution can be hydrolyzed with amylase, wherein the enzyme activity of amylase is 3000U per gram of Poria cocos, the hydrolysis temperature is 63°C, the time is 1h, and the rotation speed is 200r / min to obtain an enzymatic hydrolyzate, which is then prepared into a liquid culture medium.

[0037] Subsequently, a liquid culture medium is prepared according to the plant stock solution or the enzymatic hydrolyzate, wherein the liquid culture medium includes a carbohydrate substance, and the content of the carbohydrate substance is 4% (m / v)-10% (m / v). The present invention stipulates that the inclusion of carbohydrate substances in the liquid culture medium can provide a high-quality carbon source for the fermentation of Leuconostoc mesenteroides subsp. mesenteroides, and the inventors have found that when the content of the carbohydrate substance is 4% (m / v)-10% (m / v), it can save costs while ensuring the good growth of Leuconostoc mesenteroides subsp. mesenteroides. It is understood that the content of saccharide of 4% (m / v)-10% (m / v) means that the mass of saccharide accounts for 4%-10% of the volume of plant stock solution, i.e., the total volume of plant raw material and water. For example, when the volume of plant stock solution obtained by mixing plant raw material and water is 1L, 40-100g of saccharide is added to the plant stock solution. Specifically, the saccharide can be white granulated sugar. After adding 4% (m / v)-10% (m / v) of white granulated sugar to the plant stock solution and mixing evenly, a liquid culture medium can be obtained.

[0038] In addition, in order to avoid contamination of the fermentation process, the liquid culture medium can be sterilized. The present invention does not limit the specific operation of sterilization, and those skilled in the art can use conventional sterilization methods in the art, for example, sterilization can be performed at 115° C. for 15 minutes.

[0039] Finally, the Leuconostoc mesenteroides subsp. mesenteroides provided by the first aspect of the present invention is inoculated into a liquid culture medium and fermented, and a plant fermentation product can be obtained after the fermentation is completed. Wherein, the inoculation amount is 0.5% (v / v)-2% (v / v). The inoculation amount limited by the present invention can promote the full contact between the Leuconostoc mesenteroides subsp. mesenteroides and the liquid culture medium, and promote the full fermentation reaction. It can be understood that the inoculation amount of 0.5% (v / v)-2% (v / v) means that the volume of the seed solution of the Leuconostoc mesenteroides subsp. mesenteroides accounts for 0.5%-2% of the volume of the liquid culture medium. For example, when the volume of the liquid culture medium is 1L, 5-20mL of the seed solution of the Leuconostoc mesenteroides subsp. mesenteroides is added to the liquid culture medium. The present invention does not limit the preparation method of the seed solution of Leuconostoc mesenteroides subsp. mesenteroides, and those skilled in the art can perform the preparation according to conventional technical means. Specifically, in the present invention, the seed solution of Leuconostoc mesenteroides subsp. mesenteroides is prepared by transferring the strain of Leuconostoc mesenteroides subsp. mesenteroides to a fresh culture medium for temperature activation, and then expanding the culture until the total number of colonies is ≥10. 8 cfu / mL was obtained.

[0040] The fourth aspect of the present invention provides a plant fermentation product, wherein the plant fermentation product is obtained by the above method. Further, the plant fermentation product prepared by the method provided by the present invention has an acid polysaccharide content of ≥200mg / 100g, which can be used to prepare related products with functions such as enhancing immune function, anti-tumor, anti-oxidation, and hypoglycemic effects. Specifically, the related products include but are not limited to food and health products.

[0041] The technical solution of the present application will be further explained below in conjunction with specific examples. The experimental methods in the following examples that do not specify specific conditions are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The reagents used are commercially available or available from public channels unless otherwise specified.

[0042] Embodiment 1:

[0043] The dried dendrobium was crushed by a high-speed grinder to obtain 40-80 mesh powdered dendrobium, and then the powdered dendrobium and pure water were weighed at a mass ratio of 1:30, and then the powdered dendrobium was slowly added to the pure water at a stirring speed of 500r / min to obtain the dendrobium stock solution, to which 8% (m / v) white sugar (based on the volume of the dendrobium stock solution) was added, mixed evenly, and sterilized at 115°C for 15 minutes. After the sterilization was completed, it was taken out and naturally cooled to room temperature to obtain a liquid culture medium. The culture was expanded to a total colony count of ≥10 with an inoculum of 1% (v / v). 8 cfu / mL of Leuconostoc mesenteroides subsp. mesenteroides (CGMCC No.28494) strain was inoculated into liquid culture medium and placed in a constant temperature oscillator for fermentation. The fermentation temperature was controlled at 32°C, the fermentation time was 9 days, and the stirring speed was 150r / min to obtain the fermentation product as the experimental group.

[0044] Since Leuconostoc mesenteroides subsp. mesenteroides, Bacillus plantarum, Lactobacillus paracasei, and Lactobacillus acidophilus are all lactic acid bacteria, lactic acid bacteria may produce acidic polysaccharides during the process. Therefore, referring to the above-mentioned fermentation process, only the strain of Leuconostoc mesenteroides subsp. mesenteroides (CGMCC No. 28494) was replaced with Bacillus plantarum 6201, Lactobacillus paracasei 2103, Bacillus plantarum 6207, Bacillus plantarum 6209, Bacillus plantarum 6208, Lactobacillus acidophilus 8401, Lactobacillus paracasei 2101, and Lactobacillus paracasei 2100 for fermentation, and the obtained fermentation products can be used as a control group.

[0045] The above liquid culture medium and the fermentation products in the experimental group and the control group were subjected to alcohol precipitation to obtain crude polysaccharides, and then the acidic polysaccharides were separated and purified by ion exchange chromatography, and the acidic polysaccharide content was determined by sulfuric acid phenol method. Among them, the acidic polysaccharide content in the liquid culture medium was 261.08 mg / 100 g, and the other results are shown in Table 1. As can be seen from Table 1, the acidic polysaccharide content in the fermentation product of the experimental group was the highest, reaching 910.13 mg / 100 g, which was about 3.5 times higher than that in the liquid culture medium.

[0046] Table 1

[0047] Strain number Strain name Acidic polysaccharide (mg / 100g) 6201 Lactobacillus plantarum 169.55 2103 Lactobacillus paracasei 212.11 6207 Lactobacillus plantarum 180.00 6209 Lactobacillus plantarum 403.19 6208 Lactobacillus plantarum 226.83 8401 Lactobacillus acidophilus 90.02 2101 Lactobacillus paracasei 243.14 2100 Lactobacillus paracasei 337.85 CGMCC No.28494 Leuconostoc mesenteroides subsp. mesenteroides 910.13

[0048] Embodiment 2:

[0049] The dried Ganoderma lucidum slices were crushed by a high-speed grinder to obtain 40-80 mesh powdered Ganoderma lucidum. Then, the powdered Ganoderma lucidum and purified water were weighed at a mass ratio of 1:25, and then the powdered Ganoderma lucidum was slowly added to the purified water at a stirring speed of 300r / min to obtain the Ganoderma lucidum stock solution. 4% (m / v) of white sugar (based on the volume of the Ganoderma lucidum stock solution) was added to the solution. After mixing evenly, the solution was sterilized at 115°C for 15 minutes. After the sterilization was completed, the solution was taken out and naturally cooled to room temperature to obtain a liquid culture medium. The culture was expanded to a total colony count of ≥10 with an inoculum of 1.5% (v / v). 8 cfu / mL of Leuconostoc mesenteroides subsp. mesenteroides (CGMCC No.28494) strain was inoculated into liquid culture medium and placed in a constant temperature oscillator for fermentation. The fermentation temperature was controlled at 35°C, the fermentation time was 15 days, and the stirring speed was 150r / min to obtain the fermentation product as the experimental group.

[0050] Since Leuconostoc mesenteroides subsp. mesenteroides, Bacillus plantarum, Lactobacillus paracasei, and Lactobacillus acidophilus are all lactic acid bacteria, lactic acid bacteria may produce acidic polysaccharides during the process. Therefore, referring to the above-mentioned fermentation process, only the strain of Leuconostoc mesenteroides subsp. mesenteroides (CGMCC No. 28494) was replaced with Bacillus plantarum 6201, Lactobacillus paracasei 2203, Bacillus plantarum 6206, Bacillus plantarum 6202, Lactobacillus acidophilus 8301, Lactobacillus paracasei 2206, Lactobacillus paracasei 2210, and Lactobacillus paracasei 2211 for fermentation, and the obtained fermentation products can be used as a control group.

[0051] The liquid culture medium and the fermentation products in the experimental group and the control group were subjected to alcohol precipitation to obtain crude polysaccharides, and then the acidic polysaccharides were separated and purified by ion exchange chromatography, and the acidic polysaccharide content was determined by the sulfuric acid phenol method. Among them, the acidic polysaccharide content in the liquid culture medium was 96.33 mg / 100 g, and the other results are shown in Table 2. As can be seen from Table 2, the acidic polysaccharide content in the fermentation product of the experimental group was the highest, reaching 210.66 mg / 100 g, which was about 2.2 times higher than the acidic polysaccharide content in the liquid culture medium.

[0052] Table 2

[0053] Strain number Strain name Acidic polysaccharide (mg / 100g) 6201 Lactobacillus plantarum 14.01 2203 Lactobacillus paracasei 5.95 6206 Lactobacillus plantarum 20.26 6202 Lactobacillus plantarum 25.51 8301 Lactobacillus acidophilus 9.30 2206 Lactobacillus paracasei 13.17 2210 Lactobacillus paracasei 12.24 2211 Lactobacillus paracasei 13.10 CGMCC No.28494 Leuconostoc mesenteroides subsp. mesenteroides 210.66

[0054] Embodiment 3:

[0055] The dried Poria cocos was crushed by a high-speed pulverizer to obtain 40-80 mesh powdered Poria cocos, and then the powdered Poria cocos and pure water were weighed at a mass ratio of 1:15, and then the powdered Poria cocos was slowly added to the pure water at a stirring speed of 500r / min to obtain Poria cocos stock solution, and the Poria cocos stock solution was enzymatically hydrolyzed with amylase, wherein the enzyme activity of amylase was 3000U per gram of Poria cocos, the enzymatic hydrolysis temperature was 63°C, the time was 1h, and the speed was 200r / min to obtain an enzymatic solution, and then 8% (m / v) of white sugar (based on the volume of the enzymatic solution) was added thereto, mixed evenly, and sterilized at 115°C for 15min. After the sterilization was completed, it was taken out and naturally cooled to room temperature to obtain a liquid culture medium. The culture was expanded to a total colony count of ≥10 with an inoculum of 0.8% (v / v). 8 cfu / mL of Leuconostoc mesenteroides subsp. mesenteroides (CGMCC No.28494) strain was inoculated into liquid culture medium and placed in a constant temperature oscillator for fermentation. The fermentation temperature was controlled at 35°C, the fermentation time was 10 days, the stirring speed was 150r / min, and the fermentation product was obtained as the experimental group.

[0056] Since Leuconostoc mesenteroides subsp. mesenteroides, Bacillus plantarum, Lactobacillus paracasei, and Pediococcus pentosaceus are all lactic acid bacteria, lactic acid bacteria may produce acidic polysaccharides during the process. Therefore, referring to the above-mentioned fermentation process, only the strain of Leuconostoc mesenteroides subsp. mesenteroides (CGMCC No. 28494) was replaced with Bacillus plantarum 6201, Bacillus plantarum 6205, Bacillus plantarum 6206, Lactobacillus paracasei 2202, Lactobacillus paracasei 2203, Lactobacillus paracasei 2205, and Pediococcus pentosaceus 3190 for fermentation, and the obtained fermentation products can be used as a control group.

[0057] The above liquid culture medium and the fermentation products in the experimental group and the control group were subjected to alcohol precipitation to obtain crude polysaccharides, and then the acidic polysaccharides were separated and purified by ion exchange chromatography, and the acidic polysaccharide content was determined by sulfuric acid phenol method. Among them, the acidic polysaccharide content in the liquid culture medium was 106.34 mg / 100 g, and the other results are shown in Table 3. As can be seen from Table 3, the acidic polysaccharide content in the fermentation product of the experimental group was the highest, reaching 230.88 mg / 100 g, which was about 2.2 times higher than that in the liquid culture medium.

[0058] Table 3

[0059] Strain number Strain name Acidic polysaccharide (mg / 100g) 6201 Lactobacillus plantarum 10.24 6205 Lactobacillus plantarum ＜5 6206 Lactobacillus plantarum 21.81 2202 Lactobacillus paracasei 6.19 2203 Lactobacillus paracasei 8.27 2205 Lactobacillus paracasei 16.31 3190 Pediococcus pentosaceus ＜5 CGMCC No.28494 Leuconostoc mesenteroides subsp. mesenteroides 230.88

[0060] Embodiment 4:

[0061] The dried lily was crushed by a high-speed pulverizer to obtain 40-80 mesh powdered lily, and then the powdered lily and pure water were weighed at a mass ratio of 1:20, and then the powdered lily was slowly added to the pure water at a stirring speed of 300r / min to obtain a lily stock solution, and the lily stock solution was enzymatically hydrolyzed with amylase, wherein the enzyme activity of amylase was 1500U per gram of lily, the enzymatic hydrolysis temperature was 65°C, the time was 1h, and the speed was 150r / min to obtain an enzymatic solution, and then 6.5% (m / v) of white sugar (based on the volume of the enzymatic solution) was added thereto, mixed evenly, and sterilized at 115°C for 15 minutes. After the sterilization was completed, it was taken out and naturally cooled to room temperature to obtain a liquid culture medium. The culture was expanded to a total colony count of ≥10 with an inoculation amount of 1% (v / v). 8 cfu / mL of Leuconostoc mesenteroides subsp. mesenteroides (CGMCC No.28494) strain was inoculated into liquid culture medium and placed in a constant temperature oscillator for fermentation. The fermentation temperature was controlled at 35°C, the fermentation time was 12 days, the stirring speed was 150r / min, and the fermentation product was obtained as the experimental group.

[0062] Since Leuconostoc mesenteroides subsp. mesenteroides, Bacillus plantarum, Lactobacillus paracasei, Lactobacillus acidophilus, and Pediococcus pentosaceus are all lactic acid bacteria, lactic acid bacteria may produce acidic polysaccharides during the process. Therefore, referring to the above-mentioned fermentation process, only the strain of Leuconostoc mesenteroides subsp. mesenteroides (CGMCC No. 28494) was replaced with Bacillus plantarum 6301, Bacillus plantarum 6305, Bacillus plantarum 6306, Lactobacillus paracasei 2211, Lactobacillus paracasei 2213, Lactobacillus acidophilus 8211, and Pediococcus pentosaceus 31902 for fermentation, and the obtained fermentation products can be used as a control group.

[0063] The above liquid culture medium and the fermentation products in the experimental group and the control group were subjected to alcohol precipitation to obtain crude polysaccharides, and then the acidic polysaccharides were separated and purified by ion exchange chromatography, and the acidic polysaccharide content was determined by sulfuric acid phenol method. Among them, the acidic polysaccharide content in the liquid culture medium was 196.77 mg / 100 g, and the other results are shown in Table 4. As can be seen from Table 4, the acidic polysaccharide content in the fermentation product of the experimental group was the highest, reaching 270.50 mg / 100 g, which was about 1.4 times higher than the acidic polysaccharide content in the liquid culture medium.

[0064] Table 4

[0065] Strain number Strain name Acidic polysaccharide (mg / 100g) 6301 Lactobacillus plantarum 46.76 6305 Lactobacillus plantarum 32.16 6306 Lactobacillus plantarum 38.54 2211 Lactobacillus paracasei 11.89 2213 Lactobacillus paracasei 24.02 8211 Lactobacillus acidophilus 8.02 31902 Pediococcus pentosaceus 13.68 CGMCC No.28494 Leuconostoc mesenteroides subsp. mesenteroides 270.50

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some or all of the technical features can be replaced by equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A strain of Leuconostoc mesenteroides subsp. mesenteroides, characterized in that: It was deposited in the General Microbiology Center of China Microorganism Culture Collection Administration on September 20, 2023, with the deposit number CGMCC No.28494.

2. Use of the Leuconostoc mesenteroides subsp. mesenteroides of claim 1 in increasing the content of acidic polysaccharides in plant fermentation products.

3. A method for increasing the content of acidic polysaccharides in plant fermentation products, characterized in that: The steps include: mixing the plant material with water to obtain a plant stock solution; Prepare a liquid culture medium according to the plant stock solution; The Leuconostoc mesenteroides subsp. mesenteroides of claim 1 is inoculated into the liquid culture medium for fermentation, and a plant fermentation product is obtained after the fermentation is completed.

4. The method according to claim 3, characterized in that: The fermentation temperature is 30-40°C, the time is 9-15 days, and the stirring speed is 100-200r / min.

5. The method according to claim 3 or 4, characterized in that: The plant raw material includes at least one of dendrobium, ganoderma lucidum, poria, lily, wolfberry, cistanche, coix seed, cornus officinalis, cordyceps, rhodiola rosea and polygonatum.

6. The method according to any one of claims 3 to 5, characterized in that: The mass ratio of the plant raw material to water is 1:(5-40).

7. The method according to any one of claims 3 to 6, characterized in that: The liquid culture medium comprises sugar substances, and the content of the sugar substances is 4% (m / v)-10% (m / v).

8. The method according to any one of claims 3 to 7, characterized in that: The inoculation amount of the inoculation is 0.5% (v / v)-2% (v / v).

9. A plant fermentation product, characterized in that: The plant fermentation product is obtained by the method according to any one of claims 3 to 8.

10. The plant fermentation product according to claim 9, characterized in that: The content of acidic polysaccharides in the plant fermentation product is ≥200 mg / 100 g.