Streptococcus thermophilus with high yield of gamma-aminobutyric acid and application

Abstract

The invention discloses streptococcus thermophilus with high yield of gamma-aminobutyric acid and application, and belongs to the technical field of food microorganisms. The streptococcus thermophilus CCFM1368 strain disclosed by the invention has the capability of producing gamma-aminobutyric acid at high yield, and the yield of GABA (gamma-aminobutyric acid) can reach 1.05 g / L by taking 15g / L sodium glutamate as a substrate; after the GABA is compounded with lactobacillus bulgaricus, yoghourt is produced through fermentation, and the yield of GABA can reach 5.70 g / L after 12 h; after the GABA is compounded with lactobacillus bulgaricus, when casein hydrolysate is added, yoghourt is produced through fermentation, and the yield of GABA can reach 9.60 g / L after 12 h. The streptococcus thermophilus CCFM1368 disclosed by the invention can efficiently convert sodium glutamate into GABA with higher biological activity, and the streptococcus thermophilus CCFM1368 is applied to lactic acid bacteria products to prepare internationally recognized safe and healthy foods and has a good market prospect.

Description

Technical Field

[0001] The invention relates to a thermophilic streptococcus with high gamma-aminobutyric acid production and application thereof, belonging to the technical field of food microorganisms. Background Art

[0002] γ-aminobutyric acid (GABA) is a non-protein amino acid and an important inhibitory neurotransmitter in the central nervous system of mammals. It can also be used as a neuromodulator in peripheral tissues. It participates in a variety of metabolic activities and has high physiological activity. Studies have shown that GABA has physiological effects such as calming nerves, anti-anxiety, reducing blood ammonia, improving brain activity, promoting ethanol metabolism, and improving lipid metabolism.

[0003] GABA is a natural active ingredient that is widely distributed in animals and plants. Plants such as legumes, ginseng, and Chinese herbal medicines all contain GABA in their seeds, rhizomes, and tissue fluids. The content of GABA in animal and plant tissues is low. For example, the content in bean leaves is only 0.04 μg / g fresh weight. Therefore, it is not feasible to directly extract GABA from animals and plants and use it as a food ingredient. The main reason is that GABA exists in small amounts and is difficult to separate. In animals, GABA is almost exclusively found in nerve tissue, with the content in brain tissue being approximately 0.1-0.6 mg / g tissue.

[0004] Since GABA exists in low amounts naturally, it is difficult to extract in large quantities. Currently, most studies focus on optimizing its yield through methods such as chemical synthesis, plant enrichment, and microbial fermentation. Given the poor safety and high cost of chemical synthesis, the low content of GABA enriched in plants, and the high yield, low cost, and wide source of microorganisms of microbial fermentation, the prospect of synthesizing GABA through microbial fermentation should not be underestimated. For example, Han Xiao et al. studied the production of γ-aminobutyric acid by 68 strains of Lactobacillus brevis and Lactobacillus plantarum and found that Lactobacillus brevis DL1-11 could produce a high level of GABA with a yield of 5072 mg / L (Han Xiao, Yu Leilei, Zhai Qixiao et al. Research on the production of γ-aminobutyric acid and its key genes by Lactobacillus brevis and Lactobacillus plantarum [J]. Food and Fermentation Industries, 2019, 45(13): 1-8. DOI: 10.13995 / j.cnki.11-1802 / ts.020342.).

[0005] At present, microbial fermentation methods focus more on the optimization of fermentation conditions and the purification of the product GABA. There are few large-scale screenings of lactic acid bacteria and the selection of specific strains to optimize their GABA production in products, and the yield is still not ideal. In addition, although some lactic acid bacteria in the prior art can metabolize GABA in high yield, not all bacteria can metabolize GABA in high yield in a fermentation system containing skim milk. Individual strains can ferment and produce fermented milk with high GABA content in cow's milk containing multiple additives, but due to the complex ingredients of additives, long fermentation time, and low GABA production efficiency, it is still impossible to promote it on a large scale in industrial production. Based on the important nutritional value of GABA, there is a broad market demand for the development of fermented dairy products with high GABA content. Therefore, screening strains that can efficiently produce GABA using dairy products and single-ingredient additives to carry out fermentation production of dairy products, optimize the fermentation system and process, so as to achieve the purpose of increasing the GABA production in dairy products, has important production significance. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a strain of Streptococcus thermophilus that can use dairy products as substrates and produce high levels of GABA, and by adding GABA precursor substances, the GABA production of the strain in the product is doubled, which to a certain extent lays the foundation for new functional fermented dairy products. The strain can be used to prevent and / or treat food allergies.

[0007] In order to achieve the above objectives, the inventors screened out a strain of Streptococcus thermophilus that can metabolize high-yield GABA in a culture medium from thermophilic Streptococcus, and optimized its fermentation process. It was found that adding monosodium glutamate (L-MSG), a precursor of synthesizing GABA, to the fermentation system doubled the yield of GABA in the fermentation product of the strain. The inventors also provided a practical application of the strain in producing GABA in fermented milk, and developed yogurt rich in GABA.

[0008] The present invention provides a strain of Streptococcus thermophhilus CCFM1368, which has been deposited in Guangdong Provincial Microbiological Culture Collection Center on December 24, 2023, with a preservation number of GDMCC No: 64186.

[0009] In one embodiment of the present invention, the Streptococcus thermophhilus CCFM1368 is retained in the Food Biotechnology Strain Collection Center of Jiangnan University, with the original number DQHXN14M3.

[0010] In one embodiment of the present invention, the Streptococcus thermophhilus CCFM1368 is derived from a dairy sample. The strain is sequenced and analyzed, and the result shows that the strain is Streptococcus thermophhilus, and is named Streptococcus thermophhilus CCFM1368.

[0011] In one embodiment of the present invention, the thermophilic Streptococcus (Streptococcus thermophhilus) CCFM1368 has white raised, round, smooth-edged colonies on a GM17 solid plate, is a Gram-positive bacterium, and is cultured in a GM17 medium at a constant temperature and aerobic conditions of 42° C. for about 24 hours to reach the end of the logarithmic phase.

[0012] The present invention also provides a microbial agent containing the thermophilic streptococcus CCFM1368.

[0013] In one embodiment of the present invention, the preparation method of the microbial agent is to inoculate the above-mentioned Streptococcus thermophhilus CCFM1368 into the culture medium according to an inoculation amount of 2 to 4% of the total mass of the culture medium, and culture it at 42°C for 24 hours to obtain a culture solution; centrifuge the culture solution to obtain bacterial cells; and resuspend the bacterial cells with physiological saline to obtain a microbial agent.

[0014] In one embodiment of the present invention, the culture medium is GM17 medium.

[0015] The invention also provides a product containing the above-mentioned Streptococcus thermophhilus CCFM1368 or the microbial preparation.

[0016] In one embodiment of the present invention, the product includes food, medicine or health care product.

[0017] In one embodiment of the present invention, in the product, the viable count of the thermophilic Streptococcus thermophhilus CCFM1368 is not less than 10 7 CFU / g.

[0018] In one embodiment of the present invention, the food comprises dairy products, bean products, meat products or fruit and vegetable products produced using the above-mentioned Streptococcus thermophhilus CCFM1368 or the microbial agent; or the food comprises a solid beverage containing Streptococcus thermophhilus CCFM1368.

[0019] In one embodiment of the present invention, the medicine includes traditional Chinese medicine, biological medicine or chemical medicine.

[0020] The present invention also provides products containing metabolites, fermentation supernatants or bacterial lysates of the thermophilic streptococcus CCFM1368, wherein the products include skin care products or cosmetics, and the products do not contain living cells.

[0021] The present invention also provides a method for producing gamma-aminobutyric acid or a product containing gamma-aminobutyric acid, wherein the thermophilic streptococcus CCFM1368 is added to a culture medium containing sodium glutamate for fermentation.

[0022] In one embodiment of the present invention, the culture medium further contains casein hydrolysate.

[0023] In one embodiment of the present invention, the content of sodium glutamate in the culture medium is 10-20 g / L.

[0024] In one embodiment of the present invention, the content of casein hydrolyzate in the culture medium is 0.5-2 g / L.

[0025] In one embodiment of the present invention, the culture medium includes a conventional culture medium or dairy products; the dairy products include cow's milk, goat's milk or camel's milk; the conventional culture medium includes GM17 culture medium.

[0026] In one embodiment of the present invention, the dairy product comprises skimmed milk.

[0027] The present invention also provides the use of the thermophilic streptococcus CCFM1368 in preparing gamma-aminobutyric acid or products containing gamma-aminobutyric acid.

[0028] In one embodiment of the present invention, the product includes food, medicine, health care product or daily chemical product; the food includes fermented dairy product.

[0029] Beneficial effects:

[0030] The thermophilic Streptococcus CCFM1368 provided by the present invention has the following beneficial effects:

[0031] (1) It has the ability to produce high levels of γ-aminobutyric acid. With 15 g / L sodium glutamate as the substrate, the GABA production in GM17 medium can reach 1.054 g / L.

[0032] (2) GABA can be produced in high amounts in a culture medium containing cow's milk. After being combined with Lactobacillus bulgaricus, it can be fermented to produce yogurt. In a culture medium containing the substrate sodium glutamate, the GABA production can reach 5.70 g / L after 12 hours of fermentation; in a culture medium containing sodium glutamate and casein hydrolysate, the GABA production can reach 9.60 g / L after 12 hours of fermentation.

[0033] Therefore, the thermophilic Streptococcus CCFM1368 can be used to prepare fermented products or dairy products with high GABA content, and has broad market application prospects.

[0034] Biomaterial Deposit

[0035] A strain of thermophilic Streptococcus CCFM1368 with high production of γ-aminobutyric acid, taxonomically named Streptococcus thermophilus, was deposited in the Guangdong Provincial Microbiological Culture Collection on December 24, 2023, with the collection number GDMCCNo: 64186, and the collection address is 5th Floor, Building 59, No. 100 Xianlie Middle Road, Guangzhou. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 :Activation and preservation operation procedures of Streptococcus thermophilus.

[0037] Figure 2 : Comparison of GABA content produced by Streptococcus thermophilus in GM17 medium containing L-MSG substrate.

[0038] Figure 3 : Comparison of GABA content produced by Streptococcus thermophilus in fermented milk with and without L-MSG substrate.

[0039] Figure 4 : Comparison of GABA production by Streptococcus thermophilus in fermented milk with and without L-MSG substrate and casein hydrolysate. DETAILED DESCRIPTION

[0040] The present invention will be better understood through the following examples.

[0041] In the present invention, unless otherwise specified, "%" or percentage used to describe concentration or ratio are all weight percentages.

[0042] The present invention relates to the following culture medium:

[0043] GM17 liquid culture medium: 5 g tryptone, 5 g soy peptone, 5 g beef extract, 2.5 g yeast extract powder, 0.25 g magnesium sulfate heptahydrate, 0.5 g ascorbic acid, 19 g sodium β-glycerophosphate pentahydrate, 5 g glucose, add water to 1000 mL.

[0044] GM17 solid medium is obtained by adding 1.5% agar based on the total weight of liquid medium to the above medium.

[0045] MRS liquid culture medium: 10 g tryptone, 10 g beef extract, 5 g yeast powder, 20 g glucose, 2 g diammonium hydrogen citrate, 5 g sodium acetate, 2 g dipotassium hydrogen phosphate, 0.5 g magnesium sulfate heptahydrate, 0.25 g manganese sulfate monohydrate, 1 mL Tween 80 and 0.5 g cysteine, add water to 1000 mL.

[0046] MRS solid medium is obtained by adding 1.5% agar based on the total weight of liquid medium.

[0047] Skim milk liquid culture medium: 110g skim milk, 890g water.

[0048] The Lactobacillus bulgaricus D11M188 involved in the following embodiments is Lactobacillus delbrueckii subspecies bulgaricus D11M188, which has been disclosed in the document "Comparison of whey protein utilization ability of Lactobacillus delbrueckii subspecies bulgaricus"; the Lactobacillus brevis DL1-1 involved in the following embodiments has been disclosed in the document "Study on the production of γ-aminobutyric acid and its key genes by Lactobacillus brevis and Lactobacillus plantarum".

[0049] The thermophilic Streptococcus DQHXN10M6 and DQHXN5M3 involved in the following examples are self-selected strains.

[0050] The aerobic environment culture involved in the following embodiments refers to culture in a GRP-9080 water-proof constant temperature incubator at 42°C; the anaerobic environment culture refers to culture in an anaerobic incubator AW500SG DG250 at 37°C.

[0051] Example 1: Collection, separation and identification of thermophilic Streptococcus CCFM1368

[0052] Thermophilus streptococcus CCFM1368 was collected and isolated from dairy products in Xining, Qinghai. Take 1g of dairy products, apply it to GM17 solid culture medium after gradient dilution, place it in an anaerobic environment and culture it at 42°C for 72h, observe and record the colony morphology, pick out the colony and purify it by streaking, and then culture it in MRS liquid culture medium at 42°C for 48h, the obtained colonies are Gram-stained and the strain morphology is recorded, the Gram-negative strains and Gram-positive cocci in the colonies are discarded, and Gram-positive bacilli are selected, and all the obtained are identified as thermophilus streptococci by 16S rDNA sequencing (16S rDNA sequence is shown in SEQ ID NO.1). The obtained thermophilus streptococci are subcultured, the collected bacteria are placed in a centrifuge tube and centrifuged at 3000rpm for 10min for washing, and repeated 3 times. The obtained bacteria are added to the matrix protective agent for cryopreservation and preserved in Guangdong Microbiological Culture Collection Center, with the preservation number of GDMCC No: 64186.

[0053] 16S rDNA amplification conditions: 95°C for 5 min; 35 cycles (95°C for 30 s, 55°C for 30 s, 72°C for 2 min); 72°C for 10 min

[0054] Amplification primers: 27F: (5'-AGAGTTTGATCCTGGCTCAG-3'), 1492R: (5'-TACGGCTACCTTGTTACGACT T-3') The purification of amplified products and sequence alignment were carried out according to the method described in the literature (Turroni F et al. Exploring the Diversity of the Bifidobacterial Population in the Human Intestinal Tract [J]. Appl Environ Microb. 2009; 75 (6): 1534–45).

[0055] Example 2: Conversion of GABA by Streptococcus thermophilus CCFM1368 in medium containing L-MSG

[0056] Streak the thermophilic Streptococcus CCFM1368 culture medium on GM17 solid medium and culture it in a water-tight constant temperature incubator at 42°C for 24 hours. Pick out the grown single colonies and inoculate them in GM17 liquid medium, culture them at 42°C for 24 hours under an aerobic environment, and activate them for three generations.

[0057] The activated bacterial solution was set at a final concentration of 10 7The inoculum of CFU / mL was inoculated into 5mL GM17 liquid medium containing 1.5% sodium glutamate (L-MSG), and cultured at 42°C for 12h under an aerobic environment. At the same time, the medium with the same amount of substrate added but not the bacterial solution was used as a blank control, the medium with the same amount of substrate added and the activated Lactobacillus brevis DL1-1 bacterial solution was used as a positive control, and the medium with the same amount of substrate added and the activated Streptococcus thermophilus DQHXN10M6 bacterial solution was used as a negative control. After the fermentation, the liquid was centrifuged and filtered, and then the GABA content was determined by HPLC.

[0058] 1. Sample pretreatment

[0059] Take 1 mL of the fermented sample, centrifuge it at 6000 r / min for 5 min at 4°C, take the supernatant, filter it through a 0.22 μm microporous filter membrane, and then use it for derivatization reaction.

[0060] 2. Sample derivatization

[0061] ① Preparation of 0.4 mol / L boric acid buffer: Accurately weigh 2.47 g of boric acid, add about 80 mL of water, adjust the pH to 10.2 with NaOH, and make up to 100 mL with water.

[0062] ② Preparation of derivatization reagent: Weigh 0.1 g of o-phthalaldehyde (OPA), dissolve it in 1 mL of acetonitrile, then add 130 μL of mercaptoethanol, and dilute to 100 mL with water.

[0063] ③ Sample pre-column derivatization: Pipette 10 μL of derivatization reagent, add 10 μL of pretreated sample, mix well, react at room temperature for 90 seconds and then inject.

[0064] 3. Configuration of standard curve

[0065] GABA standard samples with concentrations of 0.05, 0.1, 0.5, 1, 2, 5, and 10 g / L were accurately prepared, and after derivatization and injection, the standard working curve was drawn with the chromatographic peak area of ​​GABA as the ordinate and the corresponding mass concentration as the abscissa. According to the liquid phase results, the concentration of GABA produced by thermophilic Streptococcus after adding substrate was obtained.

[0066] 4. GC-MS detection

[0067] Chromatographic column: XP t C18 (5μm, 4.6×250mm) liquid chromatography column

[0068] Program temperature conditions: column temperature 30°C; injection volume: 10 μL; mobile phase A is 20 mmol / L sodium acetate aqueous solution, mobile phase B is V (40 mmol / L sodium acetate aqueous solution): V (acetonitrile) = 1:1; flow rate 1 mL / min;

[0069] The elution gradient is: 0 min, 30% B; 0-14 min, 30%-50% B; 14-26 min, 50%-60% B; 26-28 min, 60%-100% B; 28-35 min, 100% B; 35-38 min, 100%-30% B; 38-47 min, 30% B;

[0070] UV detector wavelength: 338nm.

[0071] The results showed that the GABA contents detected by HPLC were: 0.204 g / L in the blank control group, 1.054 g / L in thermophilic Streptococcus CCFM1368, 1.278 g / L in Lactobacillus brevis DL1-1, and 0.206 g / L in thermophilic Streptococcus DQHXN10M6.

[0072] After analysis and comparison, it was found that thermophilic Streptococcus CCFM1368 could produce high levels of GABA in GM17 liquid culture medium containing 1.5% L-MSG substrate.

[0073] Example 3: Preparation of Streptococcus thermophilus CCFM1368 dairy product containing GABA

[0074] Activation of thermophilic Streptococcus CCFM1368 Reference Example 2: Take out the glycerol tube of Lactobacillus bulgaricus D11M188 from the -80°C refrigerator, take the bacterial liquid and streak it on MRS solid medium, and culture it in an anaerobic environment at 37°C for 24 hours. Pick out the grown single colony and inoculate it in MRS liquid medium, culture it in an anaerobic environment at 37°C for 24 hours, and activate it for three generations.

[0075] Thermophilic Streptococcus and Lactobacillus bulgaricus were co-inoculated into milk liquid culture medium to produce fermented milk. The experimental settings are shown in Table 1. The activated thermophilic Streptococcus CCFM1368 and Lactobacillus bulgaricus D11M188 bacterial liquids were inoculated at a final concentration of 10 viable cells. 7 CFU / mL inoculum was inoculated into 5mL skim milk liquid medium containing 1.5% L-MSG at the same time (CCFM1386 added substrate group), and cultured for 12h at 42°C under aerobic environment. The culture medium with equal amount of bacterial liquid but without substrate was used as blank control (CCFM1386 did not add substrate group), and the culture medium with equal amount of activated Streptococcus thermophilus DQHXN5M3 and Lactobacillus bulgaricus D11M188 bacterial liquid (with or without substrate) was used as control. The GABA content produced after fermentation was measured by HPLC, and the method was the same as in Example 2.

[0076] Table 1 Preparation of fermented milk containing GABA

[0077]

[0078]

[0079] The results showed that the GABA production of Streptococcus thermophilus CCFM1368 without adding substrate was 0.59 g / L, and the GABA production of Streptococcus thermophilus CCFM1368 with adding 15 g / L substrate was 5.70 g / L after 12 hours; the GABA production of Streptococcus thermophilus DQHXN5M3 without adding substrate was 0.41 g / L, and the GABA production of Streptococcus thermophilus DQHXN5M3 with adding 15 g / L substrate was 0.45 g / L.

[0080] After analysis and comparison, it was found that after 12 hours of compounding with Lactobacillus bulgaricus D11M188, thermophilic Streptococcus CCFM1368 could prepare yogurt containing γ-aminobutyric acid products.

[0081] By adjusting the substrate content in the culture medium to 10-20 g / L, yogurt with a high content of γ-aminobutyric acid product can be fermented.

[0082] Example 4 Preparation of fermented milk with high GABA content by thermophilic Streptococcus CCFM1368 in the presence of casein hydrolysate

[0083] Activation of thermophilic Streptococcus CCFM1368 Reference Example 2: Take out the glycerol tube of Lactobacillus bulgaricus D11M188 from the -80°C refrigerator, take the bacterial liquid and streak it on MRS solid medium, and culture it in an anaerobic environment at 37°C for 24 hours. Pick out the grown single colony and inoculate it in MRS liquid medium, culture it in an anaerobic environment at 37°C for 24 hours, and activate it for three generations.

[0084] Thermophilic Streptococcus and Lactobacillus bulgaricus were co-inoculated into milk liquid culture medium to produce fermented milk. The experimental settings are shown in Table 2. The activated thermophilic Streptococcus CCFM1368 and Lactobacillus bulgaricus D11M188 bacterial liquids were inoculated at a final concentration of 10 viable cells. 7 CFU / mL inoculum size was inoculated into 5mL skim milk liquid medium containing 1.5% L-MSG and 0.1% casein hydrolyzate (McLean, C822594) simultaneously (CCFM1386 added substrate group), and cultured for 12h at 42°C under aerobic environment. The culture medium with equal amount of bacterial liquid but without substrate was used as blank control (CCFM1386 did not add substrate group), and the culture medium with equal amount of activated Streptococcus thermophilus DQHXN5M3 and Lactobacillus bulgaricus D11M188 bacterial liquid (with or without substrate) was used as control. The GABA content produced after fermentation was measured by HPLC, and the method was the same as in Example 2.

[0085] Table 2 Preparation of fermented milk with high GABA content

[0086]

[0087] The results showed that the GABA production of Streptococcus thermophilus CCFM1368 without adding substrate was 0.63 g / L, and the GABA production of Streptococcus thermophilus CCFM1368 with 15 g / L substrate and 1 g / L casein hydrolysate was 9.60 g / L after 12 hours; the GABA production of Streptococcus thermophilus DQHXN5M3 without adding substrate was 0.61 g / L, and the production of Streptococcus thermophilus DQHXN5M3 with 15 g / L substrate was 0.65 g / L.

[0088] After analysis and comparison, it was found that when thermophilic Streptococcus CCFM1368 was compounded with Lactobacillus bulgaricus D11M188 and casein hydrolysate was added, yogurt with high γ-aminobutyric acid content could be prepared after fermentation for 12 hours.

[0089] By adjusting the substrate content in the culture medium to 10-20 g / L and the casein hydrolyzate content to 0.5-2 g / L, yogurt with a high content of γ-aminobutyric acid products can be fermented.

[0090] Example 5 Application of Streptococcus thermophilus CCFM1368 in the preparation of skin care products or cosmetics containing GABA

[0091] Streak the thermophilic Streptococcus CCFM1368 bacterial liquid on GM17 solid culture medium and culture it in a water-proof constant temperature incubator at 42°C for 24h. Pick the grown single colonies and inoculate them in GM17 liquid culture medium, culture them at 42°C for 24h under aerobic environment, and activate them for 3 generations continuously. The activated bacterial liquid is inoculated into 5mL GM17 liquid culture medium containing 1.5% sodium glutamate (L-MSG) according to the inoculation amount of 2% (v / v), and cultured at 42°C for 12h under aerobic environment. Take the fermented sample, centrifuge it at 6000r / min for 5min at 4°C, take the supernatant, and obtain the thermophilic Streptococcus CCFM1368 fermentation product.

[0092] The preparation process of lotion is as follows: ① Mix 1,3-butanediol, methylisothiazolinone, dipotassium glycyrrhizinate, sodium hyaluronate, fermentation product of Streptococcus thermophilus CCFM1368 and deionized water, and stir until dissolved; ② Stir glycerol, linolenic acid, Tween-80, vitamin A palmitate and vitamin E acetate in phase A; ③ Add the result of step ② to the result of step ①, stir evenly, and filter to obtain the lotion containing GABA.

[0093] The manufacturing process of the facial cleanser is as follows: ① dissolve fatty alcohol polyoxyethylene ether sodium sulfate, sodium lauryl sulfate, coconut oil fatty acid diethanolamide, cocamidopropyl betaine, dodecyl dimethyl ammonium oxide, glycerol and methylisothiazolinone in phase A in deionized water, and heat to 70°C while stirring; ② mix lanolin and stearic acid in phase B and heat to 70°C while stirring; ③ slowly add the obtained product of step ② to the obtained product of step ①, stir and homogenize at 65°C, cool to 45°C, add the fermentation product of thermophilic streptococcus CCFM1368 in phase C, and continue stirring; ④ stop stirring after the temperature drops to 35°C, discharge the material, and obtain the facial cleanser containing GABA.

[0094] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the definition of the claims.

Claims

1. A strain of Streptococcus thermophilus CCFM1368, characterized in that: The thermophilic Streptococcus CCFM1368 was deposited in the Guangdong Provincial Microbiological Culture Collection Center on December 24, 2023, with the collection number GDMCCNo: 64186, and the collection address is 5th Floor, Building 59, No. 100 Xianlie Middle Road, Guangzhou.

2. A microbial agent containing the thermophilic Streptococcus CCFM1368 according to claim 1.

3. A product containing the thermophilic Streptococcus CCFM1368 according to claim 1, or the microbial agent according to claim 2.

4. The product according to claim 3, characterized in that The products include food, medicine or health products; the food includes dairy products, soy products, meat products or fruit and vegetable products; the medicine includes traditional Chinese medicine, biological medicine or chemical medicine.

5. A product containing metabolites, fermentation supernatant or bacterial lysate of Streptococcus thermophilus CCFM1368 according to claim 1, characterized in that: The products include skin care products or cosmetics, and the products do not contain living cells.

6. A method for producing γ-aminobutyric acid or a product containing γ-aminobutyric acid, characterized in that: The thermophilic Streptococcus CCFM1368 described in claim 1 is added to a culture medium containing sodium glutamate for fermentation.

7. The method according to claim 6, characterized in that The culture medium also contains casein hydrolysate.

8. The method according to claim 7, characterized in that In the culture medium, the content of sodium glutamate is 10-20 g / L; the content of casein hydrolyzate is 0.5-2 g / L.

9. The method according to any one of claims 6 to 8, characterized in that: The culture medium includes conventional culture medium or dairy products; the dairy products include cow's milk, goat's milk or camel's milk; optionally, the dairy products include skimmed milk.

10. Use of the thermophilic Streptococcus CCFM1368 according to claim 1 or the microbial agent according to claim 2 in the preparation of γ-aminobutyric acid or a product containing γ-aminobutyric acid, characterized in that: The products include food, medicine, health care products or daily chemical products; the food includes fermented dairy products.

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