Acetobacter aceti as well as isolated culture method and application thereof

Abstract

The invention discloses acetobacter aceti as well as an isolated culture method and application thereof, and belongs to the technical field of microorganisms. According to the invention, an acetobacter aceti SCU-LH-1 strain is separated and screened from vinegar culture, and the preservation number is CGMCC (China General Microbiological Culture Collection Center) NO.33010. The strain provided by the invention can be used for producing litchi kernel table vinegar, lactic acid is preferentially synthesized in the fermentation process, the proportion of organic acid in the table vinegar is changed, and the proportion of lactic acid to acetic acid is remarkably increased, so that the taste of the table vinegar is effectively improved, and the table vinegar is softer and mellower; and the contents of ester components such as isoamyl acetate and lychee flavor components such as geraniol in the table vinegar are increased, so that the table vinegar has richer lychee flavor. According to the method, efficient utilization of fruit byproducts can be achieved, high-quality table vinegar is produced, reasonable utilization of resources is achieved, the raw material source of table vinegar production is expanded, the production cost is reduced, and good economic benefits and environmental benefits are achieved.

Description

Technical Field

[0001] The present invention belongs to the field of microbial technology, and particularly relates to an Acetobacter bacterium, its isolation and culture method, and application. Background Art

[0002] The litchi seed accounts for 10 - 25% of the total fruit weight and is rich in nutrients such as starch, sugars, proteins, crude fiber, etc., and has pharmacological effects such as antioxidant, anti-inflammatory, and lipid-lowering effects, but has not been effectively utilized. Producing vinegar from the by-products of fruit processing is a widely selected way to rationalize resources and increase added value, and the quality of vinegar is closely related to the specificity of acetic acid bacteria strains. In the vinegar fermented by traditional fermentation strains such as Zhongke AS1.41, Huniang 1.01, and Acetobacter rancens, acetic acid is the dominant organic acid, but the taste needs to be improved. Lactic acid can increase the softness and mellow feeling of sour taste and help improve the flavor hierarchy of food. Therefore, screening acetic acid bacteria strains with high total acid production and a high lactic acid ratio is beneficial to improving the flavor of vinegar. In view of this, obtaining a new Acetobacter bacterium that can be applied to acetic acid production is of great significance for improving the quality of acetic acid and industrial production. Summary of the Invention

[0003] The purpose of the present invention is to provide an Acetobacter bacterium to improve the quality of litchi seed vinegar, especially in terms of increasing the lactic acid content and improving the flavor.

[0004] To achieve the above purpose, in the first aspect, the present invention provides an Acetobacter bacterium named Acetobacter oryzoeni SCU-LH-1, which was deposited at the General Microbiology Center of the China Microbial Culture Collection Center on December 10, 2024, and its deposit number is CGMCC NO. 33010.

[0005] Among them, the colony morphology of the above Acetobacter bacterium on the isolation medium is: white, round, convex, opaque colonies, with a colony diameter of 3 - 4 mm, and under the microscope, it is a short rod-shaped straight form, arranged singly.

[0006] Among them, the 16S rDNA sequence of the above Acetobacter bacterium is as shown in SEQ ID NO: 1.

[0007] SEQ ID NO: 1 The 16S rDNA sequence of Acetobacter SCU-LH-1 is as follows:

[0008] CCGTGGGCGCCTTACCATGCAGTCGCACGAAGGCTTCGGCCTTAGTGGCGGACGGG

[0009] TGAGTAACGCGTAGGTATCTATCCATGGGTGGGGGATAACACTGGGAAACTGGTGCTAAT

[0010] ACCGCATGACACCTGAGGGTCAAAGGCGCAAGTCGCCTGTGGAGGAGCCTGCGTTTGA

[0011] TTAGCTAGTTGGTGGGGTAAAGGCCTACCAAGGCGATGATCAATAGCTGGTTTGAGAGG

[0012] ATGATCAGCCACACTGGGACTGAGACACGGCCCAGACTCCTACGGGAGGCAGCAGTGG

[0013] GGAATATTGGACAATGGGGGCAACCCTGATCCAGCAATGCCGCGTGTGTGAAGAAGGTC

[0014] TTCGGATTGTAAAGCACTTTCGACGGGGACGATGATGACGGTACCCGTAGAAGAAGCCC

[0015] CGGCTAACTTCGTGCCAGCAGCCGCGGTAATACGAAGGGGGCTAGCGTTGCTCGGAATG

[0016] ACTGGGCGTAAAGGGCGTGTAGGCGGTTTGTACAGTCAGATGTGAAATCCCCGGGCTTA

[0017] ACCTGGGAGCTGCATTTGATACGTGCAGACTAGAGTGTGAGAGAGGGTTGTGGAATTCC

[0018] CAGTGTAGAGGTGAAATTCGTAGATATTGGGAAGAACACCGGTGGCGAAGGCGGCAAC

[0019] CTGGCTCATTACTGACGCTGAGGCGCGAAAGCGTGGGGAGCAAACAGGATTAGATACCC

[0020] TGGTAGTCCACGCTGTAAACGATGTGTGCTAGATGTTGGGTGACTTAGTCATTCAGTGTC

[0021] GCAGTTAACGCGTTAAGCACACCGCCTGGGGAGTACGGCCGCAAGGTTGAAACTCAAA

[0022] GGAATTGACGGGGGCCCGCACAAGCGGTGGAGCATGTGGTTTAATTCGAAGCAACGCG

[0023] CAGAACCTTACCAGGGCTTGAATGTAGAGGCTGCAAGCAGAGATGTTTGTTTCCCGCAA

[0024] GGGACCTCTAACACAGGTGCTGCATGGCTGTCGTCAGCTCGTGTCGTGAGATGTTGGGT

[0025] TAAGTCCCGCAACGAGCGCAACCCCTATCTTTAGTTGCCATCAGGTTGGGCTGGGCACT

[0026] CTAGAGAGACTGCCGGTGACAAGCCGGAGGAAGGTGGGGATGACGTCAAGTCCTCATG

[0027] GCCCTTATGTCCTGGGCTACACACGTGCTACAATGGCGGTGACAGTGGGAAGCTAGGTG

[0028] GTGACACCATGCTGATCTCTAAAAGCCGTCTCAGTTCGGATTGCACTCTGCAACTCGAG

[0029] TGCATGAAGGTGGAATCGCTAGTAATCGCGGATCAGCATGCCGCGGTGAATACGTTCCC

[0030] GGGCCTTGTACACACCGCCCGTCACACCATGGGAGTTGGTTTGACCTTAAGCCGGTGAG

[0031] CGAACCGCAAGGACGCAGCCGACCACGTTCCGTACGGT。

[0032] In a second aspect, the present invention also provides a method for isolating and culturing the above-mentioned Acetobacter, which comprises the following steps:

[0033] a. Isolation of acid-producing strains: Inoculate the vinegar solid culture into the isolation medium. After cultivation, screen out several strains with strong acid-producing ability according to the size of the clear zone formed by acetic acid dissolving calcium carbonate.

[0034] b. Isolation of ethanol-tolerant and lactic acid-producing strains: Inoculate the strains screened in step a into the acid-producing medium respectively. After cultivation, screen the target strains according to the total acid and lactic acid content in the fermentation broth to obtain Acetobacter SCU-LH-1.

[0035] Among them, for the above isolation and cultivation method, in step a, the isolation medium is: 10 g of glucose, 10 g of yeast extract, 15 g of calcium carbonate, 15 g of agar powder, add 1000 mL of distilled water, natural pH, sterilize at 121 °C for 30 min, and add 20 - 60 g / L of absolute ethanol after cooling.

[0036] Among them, for the above isolation and cultivation method, in step a, the cultivation conditions are: incubate upside down at 30 °C for 48 - 72 h.

[0037] Among them, for the above isolation and cultivation method, in step a, measure the size of the clear zone of each single colony, and screen out 16 strains with strong acid-producing ability with a standard of more than 2 mm.

[0038] Among them, for the above isolation and cultivation method, in step b, the acid-producing medium is: 10 g of glucose, 10 g of yeast extract, add 1000 mL of distilled water, natural pH, sterilize at 121 °C for 30 min, and add 40 - 100 g / L of absolute ethanol after cooling.

[0039] Among them, for the above isolation and cultivation method, in step b, the cultivation conditions are: cultivate at 30 °C and 120 rpm for 72 - 120 h.

[0040] Among them, for the above isolation and cultivation method, in step b, detect the total acid and lactic acid content in the fermentation broth and screen with high content as the index.

[0041] In the third aspect, the present invention also provides the application of the above Acetobacter in the production of vinegar.

[0042] In the fourth aspect, the present invention also provides a method for producing vinegar using litchi seeds and the above Acetobacter, which includes the following steps:

[0043] A. Inoculate Acetobacter SCU-LH-1 into the activation medium for activation cultivation to obtain activated Acetobacter.

[0044] B. Inoculate the activated Acetobacter obtained in step A into the litchi seed alcohol fermentation broth fermented by active dry yeast, and obtain acetic acid fermentation broth through continuous fermentation; in step B, the inoculation amount of the activated Acetobacter is: 1×10 6 ~1×108 CFU / mL;

[0045] C. Centrifuge and remove impurities from the acetic acid fermentation broth obtained in step B, and then fill and sterilize it to obtain fermented litchi seed vinegar.

[0046] Among them, in the above method for producing vinegar, in step A, the activation medium is: 10 g of glucose, 10 g of yeast extract, add 1000 mL of distilled water, natural pH, sterilize at 121 °C for 30 min, and add 20 - 60 g / L of absolute ethanol after cooling.

[0047] Among them, in the above method for producing vinegar, in step A, the conditions for activation culture are: culture at 30 °C and 120 r / min for 24 - 48 h.

[0048] Among them, in the above method for producing vinegar, in step A, the inoculation amount of Acetobacter SCU-LH-1 is: 3 - 10%.

[0049] Among them, in the above method for producing vinegar, in step B, the alcohol content of the litchi seed alcohol fermentation broth fermented by active dry yeast is 5 - 8% vol.

[0050] Among them, in the above method for producing vinegar, in step B, the conditions for continuous fermentation are: continuous fermentation at 30 °C and 120 rpm for 3 - 5 h.

[0051] Among them, in the above method for producing vinegar, the litchi seed alcohol fermentation broth fermented by active dry yeast can be prepared by conventional processes in the art. For example, in step B, the litchi seed alcohol fermentation broth fermented by active dry yeast can be prepared by the following method: Wash the litchi seeds clean, dry, crush and sieve them to obtain fine litchi seed powder; Prepare a suspension with a concentration of 20 - 40% from the fine litchi seed powder with water, and then subject it to enzymatic hydrolysis to obtain a saccharified solution; Inoculate active dry yeast into the saccharified solution to make the cell concentration 1×10 6 ~1×10 8 CFU / mL, and ferment at 25 - 32 °C for 3 - 7 d to obtain litchi seed alcohol fermentation broth.

[0052] Among them, in the above method for producing vinegar, when preparing the litchi seed alcohol fermentation broth fermented by active dry yeast, the drying is: drying at 40 - 100 °C for 8 - 12 h.

[0053] Among them, in the above method for producing vinegar, when preparing the litchi seed alcohol fermentation broth fermented by active dry yeast, the sieving is: sieving through a 60-mesh sieve and taking the undersize.

[0054] Among them, in the above-mentioned method for producing vinegar, when preparing litchi core alcohol fermentation liquid fermented by active dry yeast, the conditions of enzymatic hydrolysis are: the suspension is gelatinized at high temperature at 110°C for 30 to 60 minutes, and when the temperature is reduced to 60°C, 300 to 1000U / mL of α-amylase (100000U / mL) is added for liquefaction, and when the iodine solution does not change color, 300 to 1000U / mL of medium-high temperature saccharifying enzyme (100000U / mL) is added for saccharification, saccharification is carried out at 60°C for 180 minutes, and the enzyme is inactivated at 90°C for 30 minutes to obtain a saccharified liquid.

[0055] Wherein, in the above method for producing vinegar, when preparing litchi core alcohol fermentation liquid fermented by active dry yeast, the active dry yeast is obtained by activating dry yeast with 3% sucrose aqueous solution.

[0056] Beneficial effects of the present invention:

[0057] (1) Increase lactic acid content and improve taste: Acetic acid is the dominant organic acid in vinegar fermented by traditional fermentation strains, and the taste needs to be improved, while lactic acid can increase the softness and mellowness of sour taste. The Acetobacter SCU-LH-1 of the present invention can significantly increase the lactic acid content in vinegar, with an increase rate of 176% compared with the traditional Zhongke AS1.41, and the lactic acid content is increased from 8.75±0.95g / L to 24.14±0.52g / L. This is because Acetobacter SCU-LH-1 optimizes the metabolic pathway during the fermentation process, preferentially synthesizes lactic acid, changes the ratio of organic acids in vinegar, and significantly increases the ratio of lactic acid to acetic acid, thereby effectively improving the taste of vinegar and making it softer and mellower.

[0058] (2) Optimizing the flavor profile and enhancing the flavor of litchi: The Acetobacter SCU-LH-1 of the present invention can improve the flavor profile of litchi core vinegar and increase the content of ester components. Among them, the ester substances are increased by 66.74% compared with Zhongke AS1.41. Ethyl acetate, butyl isovalerate and isoamyl acetate are the main different substances. Isoamyl acetate is a characteristic flavor substance of litchi, which gives the vinegar a strong "litchi aroma". At the same time, Acetobacter SCU-LH-1 also increases the content of typical flavor components of litchi such as limonene and geraniol. Geraniol has a very strong mellow odor and can produce a strong floral and fruity aroma at a lower content. It is one of the typical aroma components of litchi. The changes in these flavor substances effectively cover up the undesirable flavors such as astringency brought by litchi core, making the vinegar have a richer litchi aroma.

[0059] (3) Efficient utilization of fruit by-products, comparable to traditional raw material vinegar: The litchi seed, as a by-product of fruit processing, is rich in various nutrients but has not been effectively utilized. The Acetobacter SCU-LH-1 of the present invention can effectively utilize litchi seeds and convert them into high-quality vinegar. The yield of fermented vinegar, the total acid content and other indicators are comparable to those of vinegar made from starch raw materials such as rice. The total acid content reaches 50.5 ± 0.5 g / L, which indicates that the present invention not only realizes the rational utilization of resources, but also expands the raw material sources for vinegar production, reduces production costs, and has good economic and environmental benefits.

[0060] The preservation number of the Acetobacter of the present invention is CGMCC NO. 33010. The preservation time is December 10, 2024. The preservation center is the China General Microbiological Culture Collection Center (CGMCC), with the address at No. 3, Yard 1, Beichen West Road, Chaoyang District, Beijing, and the postal code 100101. The taxonomic name is Acetobacter oryzoeni SCU-LH-1. Brief Description of the Drawings

[0061] Figure 1 It is a colony observation diagram of the Acetobacter SCU-LH-1 of the present invention.

[0062] Figure 2 It is a cell morphology observation diagram of the Acetobacter SCU-LH-1 of the present invention.

[0063] Figure 3 It is a phylogenetic tree of the Acetobacter SCU-LH-1 of the present invention.

[0064] Figure 4 It is a physical diagram of the fine powder raw material of litchi seeds.

[0065] Figure 5 It is a physical diagram of the finished product of litchi seed fermented vinegar. Detailed Embodiments

[0066] The present invention will be further described in detail below through examples, but the protection scope of the present invention is not limited to the scope of the described examples.

[0067] In the embodiments of the present invention, the dry yeast, BV818 type, is purchased from Angel Yeast Co., Ltd.; A. pasteurianus, AS1.41 type, is purchased from the Shanghai Culture Collection Center.

[0068] Example 1: Isolation of Acetobacter for increasing lactic acid content

[0069] 1. Sample source:

[0070] The Acetobacter SCU-LH-1 in this example was isolated from the vinegar mash of a vinegar factory in Sichuan Province.

[0071] 2. Isolation of acid-producing strains:

[0072] The separation medium was used to screen strains with strong acid production ability. 16 strains with strong acid production ability were screened out by the size of the transparent circle produced by acetic acid dissolving calcium carbonate, and they were numbered C1-C16 respectively. The separation medium was: 10g glucose, 10g yeast extract, 15g calcium carbonate, 15g agar powder, 1000mL distilled water, natural pH, sterilized at 121℃ for 30min, and added 20g / L anhydrous ethanol after cooling. Inverted culture at 30℃ for 48h.

[0073] 3. Isolation of ethanol-resistant, lactic acid-producing strains:

[0074] The strains that are tolerant to high ethanol and produce flavor substances were screened through an acid-producing medium. The acid-producing medium was: 10 g of glucose, 10 g of yeast extract, 1000 mL of distilled water, natural pH, sterilized at 121°C for 30 min, and after cooling, 100 g / L of anhydrous ethanol was added. The culture was carried out at 30°C and 120 rpm for 72 h, and the target strains were screened according to the total acid and lactic acid content of the fermentation liquid.

[0075] The content of organic acids in the fermentation broth was detected by high performance liquid chromatography: 10.00 mL of the sample was taken, and the supernatant was purified by solid phase extraction column after centrifugation (4°C, 12,000 r / min, 10 min). 2 μL of the supernatant was filtered through a 0.22 μm filter membrane and detected on an HPLC (Agilent 1260, Santa Clara, USA) equipped with an Alltech OA-1000 (300 mm*6.5 mm) organic acid column. The mobile phase was 9 mmol / L H 2 SO 4 solution, flow rate 0.6mL / min, detector wavelength 215nm, and calculate the content of organic acid by external standard method.

[0076] The total acid content in the fermentation broth was detected by acid-base titration: 20 mL of the sample diluted 10 times was taken and titrated to pH 8.2 with 0.05 mol / L NaOH solution, and the NaOH consumption was recorded. The total acid content was calculated as acetic acid.

[0077] 4. Strain identification:

[0078] The C16 strain appears as white, round, convex, opaque colonies on the isolation medium, with a diameter of 3-4 mm, and is straight, short, and rod-shaped under a microscope, arranged singly; it can tolerate high ethanol growth in the acid-producing medium, and the fermented vinegar has a mellow sour taste and a higher lactic acid content than the other 15 strains. The purified C16 strain was sent to Shanghai Paisono Biotechnology Co., Ltd. for 16SrDNA sequencing, and the result is shown in SEQ ID NO: 1.

[0079] The obtained gene sequence by sequencing was submitted to the NCBI (https: / / www.ncbi.nlm.nih.gov) database for comparison. Finally, it was identified that the strain belongs to the genus Acetobacter, and its genetic relationship is closest to Acetobacter oryzoeni with a probability of 99.58%. It was experimentally confirmed that this acetic acid bacterium can rapidly produce acid during the fermentation of litchi seed vinegar, and has a high viable cell count, and can complete the fermentation in a short time. It was named SCU-LH-1.

[0080] Example 2: Application of Acetobacter for increasing lactic acid content in litchi seed vinegar

[0081] The litchi seeds were cleaned, dried at 50 °C for 12 h, crushed into powder, and passed through a 60-mesh sieve to obtain fine litchi seed powder. Its physical diagram is as Figure 4 shown. The fine litchi seed powder was prepared into a suspension with a concentration of 20 - 40%. Under the conditions of enzymatic hydrolysis (high-temperature gelatinization at 110 °C for 30 - 60 min, adding 300 - 1000 U / mL of α-amylase (100,000 U / mL) for liquefaction when the temperature was lowered to 60 °C, adding 300 - 1000 U / mL of medium-high temperature glucoamylase (100,000 U / mL) for saccharification when the iodine solution did not change color, and the saccharification conditions were 60 °C, 180 min, and hydrolyzing under inactivated enzyme (90 °C, 30 min)) to obtain a saccharified solution. Active dry yeast activated by 3% sucrose aqueous solution was inoculated to make the cell concentration 1×10 6 CFU / mL, and fermented at 25 - 32 °C for 4 d to obtain an alcoholic fermentation broth with an alcohol content of 7% vol. A. oryzoeni (Acetobacter SCU-LH-1 (CGMCC No. 33010)) activated by a liquid activation medium was inoculated to make the cell concentration 1×10 6 CFU / mL, and shake-flask fermented (30 °C, 120 rpm) until the total acid was stable (4 d), and then centrifuged (12,000 rpm, 10 min) to obtain the fermented vinegar.

[0082] The liquid activation medium was: 10 g of glucose, 10 g of yeast extract, added with 1000 mL of distilled water, natural pH, sterilized at 121 °C for 30 min, and 40 g / L of absolute ethanol was added after cooling. The inoculation amount of Acetobacter SCU-LH-1 was 3%, and it was activated and cultured at 30 °C, 120 r / min for 48 h.

[0083] Comparative Example 1: Application of traditional Acetobacter in litchi seed vinegar

[0084] For the traditional acetic acid bacteria to ferment vinegar, the specific implementation method refers to Example 2, the difference is that the inoculated acetic acid bacteria is AS1.41 (A. pasteurianus).

[0085] The litchi seed starch vinegars obtained from Example 2 and Comparative Example 1 were tested for their organic acid composition and volatile flavor components.

[0086] The content of volatile components in the vinegar was detected by headspace solid-phase microextraction gas chromatography-mass spectrometry: Exactly 0.5 mL of the vinegar sample was placed in a 15 mL headspace vial, 2 mL of saturated NaCl solution and 10 μL of internal standard (2-octanol, 0.1 g / L) were added, and it was equilibrated in a constant temperature water bath at 60 °C for 15 min and extracted for 40 min. It was inserted into the GC-MS injection port for desorption for 5 min. The temperature programming was as follows: hold at 40 °C for 5 min, then increase to 100 °C at a rate of 4 °C / min, and then increase to 230 °C at a rate of 6 °C / min and hold for 10 min. The EI electron energy was 70 eV, and the carrier gas was high-purity helium at 1.0 mL / min. The peak area of the internal standard 2-octanol was used for semi-quantitative analysis of the compounds, and the test results are shown in Table 2.

[0087] The total cyanide in the vinegar was determined by silver nitrate titration: It was carried out with reference to the first method in the Chinese National Environmental Protection Standard HJ 484—2009.

[0088] Table 1 Effects of Acetobacter SCU-LH-1 on the total acid and organic acids in litchi fermented vinegar

[0089]

[0090]

[0091] The results showed that Example 2 inoculated with Acetobacter SCU-LH-1 (CGMCC No. 33010) significantly improved the organic acid composition of litchi fermented vinegar on the premise that there was no significant difference in the total acid content. Six organic acids such as citric acid were detected in Example 2, with a content of 45.08 ± 1.22 g / L; seven organic acids such as oxalic acid were detected in Comparative Example 1, with a content of 46.4 ± 3.05 g / L. The contents of citric acid, succinic acid, and lactic acid in Example 2 increased by 224%, 720%, and 176% compared with Comparative Example 1, the contents of tartaric acid, malic acid, and acetic acid decreased, and oxalic acid was not detected. The ratio of lactic acid to acetic acid affected the flavor and taste of the vinegar, and this ratio reached 0.29 and 2.17 in Comparative Example 1 and Example 2 respectively. The increase in the lactic acid content improved the sensory quality of the vinegar. Therefore, Acetobacter SCU-LH-1 (CGMCC No. 33010) can be used as a fermenting agent for vinegar products to increase the lactic acid content.

[0092] Table 2 Effects of Acetobacter SCU-LH-1 on the volatile substances in litchi fermented vinegar

[0093]

[0094]

[0095] As can be seen from Table 2, the content of esters in Example 2 increased by 66.74% compared with Comparative Example 1. Ethyl acetate, butyl isovalerate, and isoamyl acetate are the main differential substances, among which isoamyl acetate is the characteristic flavor substance of litchi, giving the vinegar a strong "litchi fragrance". In terms of alcohol components, the alcohol content in Comparative Example 1 was 5328.9 μg / L, higher than 2817.9 μg / L in Example 2. The high content of phenethyl alcohol (3404.87 ± 414.09 μg / L) was mainly responsible for this difference. Geraniol, a characteristic component detected in Example 2, has a very strong mellow odor and can produce a strong floral and fruity fragrance even at a low content. It is one of the typical aroma components of litchi and makes an important contribution to the aroma of the vinegar. Although the alcohol component content in Example 2 is lower than that in Comparative Example 1, the retention of several typical litchi flavors can mask the unpleasant flavors such as astringency brought by litchi pits. Total cyanide was not detected in each group of vinegar.

[0096] In summary, litchi pit powder is a type of safe starch raw material. The acetic acid bacteria SCU-LH-1 (CGMCC No. 33010) provided by the present invention can be used for the acetic acid fermentation of litchi pit vinegar, which can well improve the quality of vinegar.

[0097] Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Anyone familiar with this technology can make various modifications and decorations without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be defined by the claims.

Claims

1. Acetobacter, characterized in that: The strain of Acetobacter oryzoeni is named Acetobacter oryzoeni SCU-LH-1, which is deposited in the General Microbiological Center of China Microbiological Culture Collection Administration, and its deposit number is CGMCCNO.33010.

2. The method for isolating and culturing Acetobacter according to claim 1, characterized in that: The following steps are involved: a. Isolation of acid-producing strains: inoculate the vinegar mash into the separation medium, and after culturing, screen out several strains with strong acid-producing ability by the size of the transparent circle produced by acetic acid dissolving calcium carbonate; b. Isolation of ethanol-resistant, lactic acid-producing strains: The strains screened in step a were inoculated into acid-producing culture media respectively. After cultivation, the target strains were screened according to the total acid and lactic acid content of the fermentation broth to obtain Acetobacter SCU-LH-1.

3. The method for isolating and culturing Acetobacter according to claim 2, wherein: At least one of the following is met: In step a, the separation medium is: 10 g glucose, 10 g yeast extract, 15 g calcium carbonate, 15 g agar powder, 1000 mL distilled water, natural pH, sterilized at 121° C. for 30 min, and after cooling, 20 to 60 g / L of anhydrous ethanol is added; In step a, the culture conditions are: inverted culture at 30° C. for 48 to 72 hours; In step a, the size of the transparent zone of each single colony was measured, and 16 strains with strong acid production ability were screened out with a standard of being larger than 2 mm.

4. The method for isolating and culturing Acetobacter according to claim 2, characterized in that: At least one of the following is met: In step b, the acid-producing medium is: 10 g of glucose, 10 g of yeast extract, 1000 mL of distilled water, natural pH, sterilized at 121° C. for 30 min, and after cooling, 40-100 g / L of anhydrous ethanol is added; In step b, the culture conditions are: 30° C., 120 rpm, and 72 to 120 h.

5. Use of the acetobacter according to claim 1 in producing vinegar.

6. A method for producing vinegar using litchi pits and acetic bacteria, characterized in that: The following steps are involved: A. inoculating Acetobacter SCU-LH-1 into an activation culture medium for activation culture to obtain activated Acetobacter; B. Inoculate the activated acetic acid bacteria obtained in step A into the litchi kernel alcohol fermentation liquid fermented with active dry yeast, and obtain acetic acid fermentation liquid through continuous fermentation; in step B, the inoculation amount of the activated acetic acid bacteria is: 1×10 6 ~1×10 8 CFU / mL; C. The acetic acid fermentation liquid obtained in step B is centrifuged to remove impurities and filled and sterilized to obtain litchi core fermented vinegar.

7. The method for producing vinegar using litchi pits and acetobacter according to claim 6, characterized in that: At least one of the following is met: In step A, the activation medium is: 10 g glucose, 10 g yeast extract, 1000 mL distilled water, natural pH, sterilized at 121° C. for 30 min, and after cooling, 20 to 60 g / L of anhydrous ethanol is added; In step A, the activation culture conditions are: 30° C., 120 r / min, 24 to 48 h; In step A, the inoculation amount of the Acetobacter SCU-LH-1 is 3-10%.

8. The method for producing vinegar using litchi pits and acetobacter according to claim 6, characterized in that: At least one of the following is met: In step B, the alcohol content of the litchi core alcohol fermentation liquid fermented with active dry yeast is 5-8% vol; In step B, the continuous fermentation conditions are: 30° C., 120 rpm, and continuous fermentation for 3 to 5 hours.

9. The method for producing vinegar using litchi pits and acetic bacteria according to claim 6, characterized in that: In step B, the litchi kernel alcohol fermentation liquid fermented with active dry yeast is prepared by the following method: cleaning the litchi kernels, drying, crushing and sieving to obtain litchi kernel fine powder; using water to prepare the litchi kernel fine powder into a suspension with a concentration of 20-40%, and hydrolyzing with enzymes to obtain a saccharified liquid; inoculating active dry yeast into the saccharified liquid to make the bacterial concentration 1×10 6 ~1×10 8 CFU / mL, ferment at 25-32℃ for 3-7 days to obtain litchi core alcohol fermentation liquid.

10. The method for producing vinegar using litchi pits and acetic bacteria according to claim 9, characterized in that: When preparing litchi kernel alcohol fermentation liquid fermented with active dry yeast, at least one of the following is met: The drying step is: drying at 40-100° C. for 8-12 hours; The sieving comprises: passing through a 60-mesh sieve and taking the sieve-undersized material; The conditions of the enzymatic hydrolysis are as follows: gelatinize the suspension at 110° C. for 30 to 60 minutes, add 300 to 1000 U / mL of α-amylase to liquefy the suspension when the temperature drops to 60° C., add 300 to 1000 U / mL of medium-high temperature saccharifying enzyme to saccharify the suspension when the iodine solution does not change color, saccharify the suspension at 60° C. for 180 minutes, inactivate the enzyme at 90° C. for 30 minutes, and obtain a saccharified liquid. The active dry yeast is obtained by activating dry yeast with a 3% sucrose aqueous solution.

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