Bacteria producing aroma and application thereof

Abstract

The application discloses a strain of aroma-producing bacteria and application thereof, wherein the aroma-producing bacteria is identified as Heyndrickxia oleronia, has been preserved in the China General Microbiological Culture Collection Center on October 25, 2023, has a preservation number of CGMCC 28772, and is named as SQJ6. The aroma-producing bacteria SQJ6 provided in the application can ferment to produce volatile flavor substances such as 3-ethyl-2,5-dimethylpyrazine, ethyl isovalerate, 2-methylbutyric acid ethyl ester, 6-ethyl-2,3,5-trimethylpyrazine and ethyl phenylacetate. The strain can be used for intensified fermentation in an alcohol fermentation stage, does not affect the fermentation acid production of a main acid-producing bacteria strain of acetobacter pasteurii after intensification, can improve the content of volatile flavor components such as alcohols, esters, aldehydes and pyrazines of a final product of vinegar, can be used as a vinegar flavoring fermentation strain, and can improve the quality of vinegar.

Description

Technical Field

[0001] This invention belongs to the field of microbiology, and in particular relates to an aroma-producing bacterium and its applications. Background Technology

[0002] Vinegar is an important acidic condiment. Besides its primary acidity, the aroma of vinegar is a crucial factor determining its quality. The flavor profile of vinegar includes acidity, sweetness, caramelization, soy sauce aroma, fruitiness, bran aroma, smokiness, rice aroma, wine aroma, and floral aroma. The strength of these different aromas contributes to the distinctive flavor profile of vinegar. The sweetness, fruitiness, and floral aromas in vinegar primarily depend on microbial fermentation, especially microorganisms that produce volatile substances.

[0003] Currently, commercially available vinegar products are largely homogenized in flavor, differing only in their saltiness and sweetness. There are few vinegar products with distinctive flavors, and consumers are hesitant to consume vinegar made with artificial flavorings. By enhancing fermentation with microorganisms that produce distinctive aromas, vinegar can be given its characteristic aromas without affecting its sourness, thus improving its quality.

[0004] The species *Heyndrickxia oleronia* was first isolated by Kuhnigk in 1996 from the gut of termites on the Île d'Oléron in France, and was initially named *Bacillus oleronius*. In 2020, Gupta reclassified the *Bacillus* genus based on genetics and renamed this species *Heyndrickxia oleronia*. Some strains of *Heyndrickxia oleronia* have been reported to have the ability to degrade polysaccharides, cellulose, proteins, and plant-derived phenolic acids, and can be used as microbial fertilizer (patent number CN116063128A), fermentation agents for treating fruit and vegetable wastewater and vegetable tail wastewater (patent numbers CN114350556A, CN114540219A, CN114606154A), and can also be applied to tobacco fermentation to improve tobacco quality (patent number CN115838663A). However, the role and application of this species in aroma production and enhancing the aroma of fermented foods have not yet been reported. Summary of the Invention

[0005] Purpose of the invention: In order to solve the above-mentioned technical problems, the present invention aims to provide a fragrance-producing bacterium with excellent fragrance production and tolerance to ethanol and acetic acid.

[0006] This invention also provides the application of aroma-producing bacteria in the production of spices and the enhancement of aroma in fermented vinegar.

[0007] Technical solution: In order to achieve the above objectives, the present invention provides an aroma-producing bacterium, identified as Heyndrickxia oleronia, which has been deposited at the China General Microbiological Culture Collection Center on October 25, 2023, with the accession number CGMCC 28772 and named SQJ6.

[0008] The aroma-producing fungus SQJ6 described in this invention is isolated from traditional Chinese vinegar fermentation mash. The colonies are flesh-colored, moist, and irregular in shape; Gram-positive, aerobic, and spore-producing.

[0009] Furthermore, the 16S rDNA nucleotide sequence of the aroma-producing bacteria is shown in SEQ ID No. 1.

[0010] The application of the aroma-producing bacteria described in this invention in fragrance production.

[0011] The fragrance includes 3-ethyl-2,5-dimethylpyrazine, ethyl isovalerate, ethyl 2-methylbutyrate, 6-ethyl-2,3,5-trimethylpyrazine, and ethyl phenylacetate.

[0012] The application of aroma-producing bacteria in enhancing the flavor of vinegar according to the present invention.

[0013] Among them, the application of the aroma-producing fungus SQJ6 in solid-state fermented vinegar.

[0014] Furthermore, the aroma-producing bacteria enhance fermentation during the alcoholic fermentation stage of vinegar fermentation, thereby increasing the content of volatile flavor components in the vinegar product.

[0015] Furthermore, during the alcoholic fermentation stage, Angel Yeast rice wine starter and Oleonella SQJ6 culture medium are mixed in before proceeding with the acetic acid fermentation described above.

[0016] Furthermore, the application of the aroma-producing fungus SQJ6 in increasing the total amount of any one or more volatile flavor compounds, such as 2-methoxy-5-methylphenol, trimethylpyrazine, and tetramethylpyrazine, in vinegar.

[0017] Furthermore, the application of the aroma-producing fungus SQJ6 in increasing the total amount of any one or more volatile flavor compounds, such as alcohols, esters, or aldehydes, in vinegar.

[0018] Furthermore, the alcohol is any one or more of isobutanol, phenylethanol, and 2,3-butanediol.

[0019] Further, the esters are any one or more of isoamyl acetate, ethyl 2-methylbutyrate, ethyl isovalerate, diethyl succinate, ethyl phenylacetate, hexyl acetate, ethyl octanoate, ethyl acetate, isooctyl acetate, ethyl nonanoate, ethyl palmitate, phenylethyl acetate, ethyl benzoate, and γ-nonanolide.

[0020] Furthermore, the aldehydes are any one or more of 3-hydroxy-2-butanone, isovaleraldehyde, isophorone, furfural, phenylacetaldehyde, and 3,4-dimethylbenzaldehyde.

[0021] Furthermore, the isolation and screening steps for aroma-producing microorganisms are as follows:

[0022] Zhenjiang vinegar mash was serially diluted using standard methods. The diluted solutions were spread onto GYE solid medium and incubated at 30°C for 48 hours. Single colonies were then picked and purified three times on GYE solid medium using the streak plating method to obtain pure cultures. The isolated pure strains were inoculated onto GYE solid plates, and the plates were sealed with sealing film and incubated at 30°C for 48 hours. The odor produced by the culture was used as the initial screening. The odor of the liquid fermentation broth was used for secondary screening using the odor method. Based on the comprehensive odor characteristics, presence of off-odors, and odor intensity, the strain SQJ6 with the best aroma-producing effect was selected from the 30 initial strains.

[0023] The GYE culture medium consists of: 2% glucose, 1% yeast powder, 2% agar powder, and 3% ethanol (sterilized and then added).

[0024] Furthermore, the strain SQJ6 provided by this invention was amplified by PCR using universal bacterial primers 27F and 1492R. After sequencing, a 16S rRNA gene sequence of 1411 bp was obtained. The sequence was submitted to the Ezbiocloud 16S database for comparison, which showed that the 16S rDNA gene similarity between strain SQJ6 and Heyndrickxia oleronia DSM 9356 was 98.93%. Therefore, strain SQJ6 was classified and named Heyndrickxia oleronia.

[0025] Furthermore, the strain SQJ6 provided by this invention cannot produce acid, lacks the ability to produce extracellular proteases and cellulases, but possesses the ability to produce extracellular esterases and amylases. Strain SQJ6 can grow weakly in acetic acid at concentrations up to 10 g / 100 mL and exhibits good ethanol tolerance, growing excellently in ethanol concentrations up to 6% (v / v), with an optimal ethanol concentration of 2% (v / v).

[0026] Furthermore, the strain SQJ6 provided by this invention can produce a rich fruity aroma without any other unpleasant odors under both solid and liquid GYE culture. Solid-phase microextraction combined with GC-MS identification showed that the main volatile aroma compounds produced by the 48-hour fermentation broth on GYE medium were 3-ethyl-2,5-dimethylpyrazine (7.52 g / L), ethyl isovalerate (4.46 g / L), ethyl 2-methylbutyrate (2.72 g / L), 6-ethyl-2,3,5-trimethylpyrazine (2.00 g / L), and ethyl phenylacetate (0.54 g / L). The aroma-producing properties of strain SQJ6 indicate its potential for development as a fragrance raw material.

[0027] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0028] The aroma-producing *Oleurotus ostreatus* isolated from fermented vinegar mash provided by this invention can ferment in culture medium to produce a rich fruity flavor. Its main volatile components are 3-ethyl-2,5-dimethylpyrazine, ethyl isovalerate, ethyl 2-methylbutyrate, 6-ethyl-2,3,5-trimethylpyrazine, and ethyl phenylacetate, providing a microbial resource for fragrance production.

[0029] The *Hydroxylon oryzae* SQJ6 strain provided by this invention is used for enhanced fermentation in the alcoholic fermentation stage of vinegar production to improve the aroma of fermented vinegar. After enhancement, it does not affect the fermentation and acid production of *Acetobacter pasteurellii*, the main acid-producing bacterium in vinegar production, but can increase the content of alcohols, esters, aldehydes, and other volatile flavor components in the final vinegar product, especially producing esters with fruity aromas and pyrazines with roasted aromas. This strain can be used as a flavor-enhancing fermentation strain for vinegar, applied in the fermentation production of vinegar to improve its quality. Attached Figure Description

[0030] Figure 1 The images show the colony morphology and cell morphology of *Oleuronectiformis* SQJ6 of this invention; where (a) is a colony morphology of the strain on GYE solid medium containing CaCO3, and (b) is a microscopic image of the cells after Gram staining.

[0031] Figure 2 This is a phylogenetic tree diagram of the 16S rDNA gene of *Oleurotus erythrorhizium* SQJ6 of this invention and similar strains.

[0032] Figure 3 The turbidity diagram of *Hydroxylon ammodendron* SQJ6 under different acetic acid (a) and ethanol (b) contents is shown in the present invention.

[0033] Figure 4 This is a graph showing the GC-MS detection results of the fermentation broth of *Hydroxylon ammodendron* SQJ6 according to the present invention;

[0034] Figure 5This is a graph showing the change in total acidity during vinegar fermentation enhanced by the Oleuronecti SQJ6 strain of the present invention. Detailed Implementation

[0035] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0036] Unless otherwise specified, all materials and reagents used in the following examples are commercially available. Experimental methods not specifically described in the examples are generally performed under standard conditions or as recommended by the manufacturer.

[0037] Example 1

[0038] Strain screening and identification

[0039] The vinegar mash collected from Zhenjiang City was serially diluted with sterile water and spread onto GYE solid medium (2% glucose, 1% yeast powder, 2% agar powder, and 3% ethanol added after sterilization) and incubated at 30°C for 48 hours. After colonies grew, single colonies were picked and streaked onto GYE solid medium for purification. The purification was repeated three times to obtain pure cultures.

[0040] Colony plates cultured for 48 hours were initially screened by direct smelling of the culture in a clean bench. Thirty strains were then selected for secondary screening. Secondary screening was conducted using GYE liquid medium (2% glucose, 1% yeast extract, and 3% sterilized ethanol added), selecting strains with good growth by smelling the fermentation broth. During secondary screening, some strains showed very weak fermentation odors, while others exhibited noticeable off-odors. Ultimately, the strain with the strongest, fruity, and odorless fermentation broth was selected and named SQJ6 for further research.

[0041] On GYE medium, strain SQJ6 colonies are flesh-colored, moist, and irregular in shape, such as... Figure 1 As shown in (a); Gram staining microscopic observation of the target bacterial cells revealed that SQJ6 bacterial cells are rod-shaped, capable of producing spores, and Gram-positive, as indicated by... Figure 1 As shown in (b).

[0042] The identification of strain SQJ6 was performed using rapid 16S rDNA identification. Specifically, an appropriate amount of bacterial cells was added to 50 μL of sterile pure water and heated at 100°C for 10 min in a PCR instrument. The supernatant was used as a template, and PCR amplification was performed using universal bacterial primers 27F and 1492R. The PCR amplification system consisted of 1 μL template DNA, 1 μL each of primers, and 2*PCR Hero... TMMix (dye) 12.5 μL (Foregene) and ddH2O 9.5 μL. The PCR amplification program was as follows: pre-denaturation at 95℃ for 5 min, denaturation at 95℃ for 20 s, annealing at 55℃ for 20 s, extension at 72℃ for 40 s, 30 cycles, followed by a final extension at 72℃ for 5 min. The PCR amplification product was sent to Wistron NeWeb for sequencing. The 16S rDNA fragment of strain SQJ6 was amplified, yielding a length of 1411 bp, and the gene sequence is shown in SEQ ID No. 1. The sequencing sequence was submitted to the Ezbiocloud 16S database for alignment, and a phylogenetic tree was constructed using MEGA with the 16S rDNA genes of similar strains.

[0043] The 16S rDNA identification results of strain SQJ6 showed that it had 98.93% similarity to the 16S rDNA gene of Heyndrickxia oleronia DSM 9356. Combined with physiological and biochemical characteristics, strain SQJ6 was identified as Heyndrickxia oleronia. Figure 2 This is a phylogenetic tree of the 16S rDNA genes of strain SQJ6 of this invention and its closely related strains. This strain was deposited on October 25, 2023, at the China General Microbiological Culture Collection Center (CGMCC), Institute of Microbiology, Chinese Academy of Sciences, No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, with accession number CGMCC28772, and its taxonomic name is *Heyndrickxia oleronia*, strain name SQJ6.

[0044] Example 2

[0045] Enzyme production characteristics and tolerance of Oleronae SQJ6

[0046] Oleocystis olleroides SQJ6 was cultured in GYE liquid medium to the logarithmic phase. 5 μL of the bacterial culture was then inoculated onto the following solid medium plate. The presence or absence of a clear zone was used to preliminarily assess whether it possesses the properties of producing acid, protease, amylase, cellulase, and esterase.

[0047] The culture medium for detecting acid production capacity was GYE plus CaCO3 solid medium (2% glucose, 1% yeast extract, 2% agar powder, 3% ethanol sterilized and added, 1% CaCO3). The culture media for detecting protease, amylase, cellulase and esterase production capacity were 0.5% skim milk powder, 0.5% soluble starch, 0.5% sodium carboxymethyl cellulose and 0.2% tributyrate respectively added to the basal medium (1% glucose, 0.5% yeast extract, 2% agar powder). Protease and esterase production were detected by directly observing the presence of clear zones on the plates. Amylase production capacity was detected by adding iodine solution after 72 h of cell culture and observing the presence of clear zones. Cellulase production capacity was detected by adding 1 mg / mL Congo red solution for staining for 10-15 min after 72 h of cell culture, followed by adding 1 mol / L NaCl for 15 min, discarding the washing solution and observing the presence of clear zones on the plates. Experimental results show that *Oleuronectiformis* SQJ6 cannot hydrolyze defatted milk powder and cellulose, but can hydrolyze tricresyl esters and starch. Therefore, this strain does not have the ability to produce extracellular proteases and cellulases, but it has the ability to produce extracellular esterases and amylases.

[0048] Oligosacchariformis SQJ6 was cultured in GYE liquid culture to the logarithmic development phase. It was then inoculated at a 1% (v / v) in basal medium containing 0, 1, 2, 4, 6, 8, and 10 g / 100 mL acetic acid (1% glucose, 0.5% yeast extract). Similarly, it was inoculated at a 1% (v / v) in basal medium containing 0, 2, 4, 6, 8, 10, and 12% (v / v) ethanol (1% glucose, 0.5% yeast extract) and incubated at 30°C for 48 h. The OD600 absorbance of the culture was measured to preliminarily assess its tolerance to acetic acid and ethanol.

[0049] The acid resistance of Oleronae SQJ6 is as follows Figure 3 (a) shows that the best growth was observed in basal medium with 0 g / 100 mL acetic acid, with weak growth in basal medium with 2-10 g / 100 mL acetic acid, and the passaged strains still grew well after being transferred to GYE medium without acetic acid. The ethanol tolerance of *Oleuronectiformis* SQJ6 is as follows: Figure 3 (b) shows that the strain grows best at 2% ethanol concentration, grows well at 0-6% ethanol concentration, and shows no growth in ethanol media with concentrations above 8%. Therefore, *Oleuronecti* SQJ6 can grow weakly in acetic acid up to 10 g / 100 mL and can tolerate ethanol concentrations of 0-6%.

[0050] Example 3

[0051] Analysis of volatile aroma compounds produced by strain SQJ6

[0052] Oleocystis ollerans SQJ6 cultured to the logarithmic phase was inoculated into GYE liquid medium at a volume ratio of 1%. After incubation at 30℃ and 180 rpm / min for 48 h, the volatile flavor compounds of the fermentation broth were measured. Each sample was performed in triplicate.

[0053] Take 6 mL of fermentation broth, add 2.5 g of sodium chloride and 10 μL of 2-octanol internal standard (25 mg / L) to a 20 mL headspace vial for analysis. Place the vial in a rotor, tighten the cap, and put it in a 55°C water bath equipped with a magnetic stirrer. Extract volatile components for 40 min using a 50 / 30 μm DVB / CAR / PDMS extraction fiber (Supelco, USA). After extraction, desorb the volatile components for 5 min at 250°C through the injection port of an ISQ single quadrupole GC-MS instrument.

[0054] Gas chromatography-mass spectrometry (GC-MS) was used (Agilent Technologies, USA, 6890N-5975B). The column was DB-WAX (30m × 0.25mm × 0.25um). The injection port temperature was 220℃, and the carrier gas He flow rate was 1 mL / min. The conditions were: initial temperature 40℃, increased to 150℃ at 4℃ / min, then increased to 250℃ at 8℃ / min and held for 6 min, with split injection at a split ratio of 5. MS conditions: interface temperature 220℃, ion source temperature 230℃, full scan data acquisition mode, electron energy 70 eV, mass scan range 35–500 mL / z.

[0055] After GC-MS analysis of the fermentation broth and sterilized blank culture medium, obvious compound peaks were observed, as shown in the results. Figure 4 As shown in Table 1, by comparing the changes in volatile substances before and after cultivation, strain SQJ6 can produce five main volatile compounds after 48 hours of cultivation. In order of elution, they are ethyl 2-methylbutyrate, ethyl isovalerate, 3-ethyl-2,5-dimethylpyrazine, 6-ethyl-2,3,5-trimethylpyrazine, and ethyl phenylacetate. Detailed information is shown in Table 1. The aroma-producing properties of strain SQJ6 indicate its potential for developing aroma raw materials.

[0056] Table 1. Detailed information on volatile components in the fermentation broth of *Hydrilla verrucosum* SQJ6.

[0057]

[0058] Example 4

[0059] Application of aroma-producing strain SQJ6 in solid-state fermented vinegar

[0060] 1. Vinegar fermentation

[0061] Control Group A: The brewing process for Zhenjiang fragrant vinegar was slightly modified from the traditional brewing process. Specifically: Alcoholic fermentation: 1 kg of glutinous rice was weighed, washed clean, and soaked for 12 hours. The rice was then steamed using a rice steamer. After rinsing with cold water until the rice temperature reached approximately 40℃, 6 g of commercially available Angel rice wine yeast was mixed in and the mixture was fermented. 24 hours after fermentation, 2 kg of water was added, stirred well, and fermentation continued for 4 days. The alcohol content of the fermentation liquid was measured and diluted to 9% (v / v) to obtain the diluted mash, which was then used for acetic acid fermentation.

[0062] Acetic acid fermentation: Weigh 240g of wheat bran and 112.8g of rice bran into a 2L plastic bucket, add 600mL of the diluted mash solution, and stir well to obtain vinegar mash. Inoculate fresh vinegar mash with a 1% (v / v) culture of *Acetobacter pasteurellium* Hu Brewing 1.01 (purchased from CICC, catalog number CICC 20001). Turn the mash once daily until the total acidity no longer increases. Add salt to compact the mash, cover with plastic film, and seal for 7 days. After sealing, leach vinegar and store.

[0063] Experimental Group B: Following the vinegar fermentation method of Control Group A, Angel rice wine yeast was mixed in during the alcoholic fermentation stage, and at the same time, the logarithmic activated culture medium of Oleella ovale SQJ6 was inoculated at a volume ratio of 0.5%, and then the above acetic acid fermentation was carried out.

[0064] Experimental Group C: Following the vinegar fermentation method of Control Group A, Acetobacter pasteurella multocida 1.01 was inoculated during the above acetic acid fermentation stage, and simultaneously, Oleella oleracea SQJ6 logarithmic phase activated culture medium was inoculated at a volume ratio of 0.5% for fermentation.

[0065] During the acetic acid fermentation stage in control group A, experimental group B, and experimental group C, the total acidity of the brine was measured daily (specific steps refer to GB / T 5009.41-2003 "Analytical Methods for Hygienic Standards of Vinegar"). The volatile flavor compounds of the vinegar leached after fermentation were determined using solid phase microextraction and gas chromatography-mass spectrometry (methods are the same as in Example 3). Each sample was tested in triplicate.

[0066] The total acid content of the three acetic acid fermentation processes is as follows: Figure 5 As shown, the total acidity of the three groups of fermented vinegars increased with fermentation time. The acidity increased rapidly during fermentation 1-4 days, and remained basically unchanged during fermentation 5-6 days. The final acidities were 5.89 g / 100 mL for group A, 5.86 g / 100 mL for group B, and 5.86 g / 100 mL for group C. It can be seen that the enhanced fermentation of Oleuronecti SQJ6 in both the alcoholic and acetic acid fermentation stages did not affect the acidity of the final product.

[0067] Table 2 shows the volatile flavor components of vinegar after enhanced fermentation with *Hydroxylon ammodendron* SQJ6. Among the three groups, experimental group B contained the most types and the largest total amount of volatile flavor components. Compared with the unenhanced control group A, experimental group B, i.e., the alcohol-enhanced group, increased the total amount of alcohols (increased by 13.1%), esters (increased by 42.3%), aldehydes (increased by 10.3%), and other types (increased by 8.6%) of volatile flavor substances in vinegar. Among them, the increase in esters was the most significant, specifically the increased content of isoamyl acetate, ethyl 2-methylbutyrate, ethyl isovalerate, diethyl succinate, ethyl phenylacetate, hexyl acetate, ethyl octanoate, ethyl acetate, isooctyl acetate, ethyl nonanoate, ethyl palmitate, phenylethyl acetate, ethyl benzoate, and γ-nonanolide. Ethyl 2-methylbutyrate, ethyl isovalerate, and ethyl phenylacetate produced by *Hydroxylon olleronii* SQJ6 in the fermentation broth were detected in experimental group B, and their contents were significantly higher than those in the control group. 3-ethyl-2,5-dimethylpyrazine and 6-ethyl-2,3,5-trimethylpyrazine produced by *Hydroxylon olleronii* SQJ6 in the fermentation broth were not detected in experimental group B, but small amounts of trimethylpyrazine (0.0003 g / L) and tetramethylpyrazine (0.0219 g / L) were detected in experimental group B. Compared with control group A, the total amount of acids detected in experimental group B was slightly reduced (9.4541 mg / L in group A, 8.8889 mg / L in group B, but the difference was negligible). Specifically, the contents of acetic acid, valeric acid, hexanoic acid, octanoic acid, heptanoic acid, and 2-heptenoic acid decreased, while the contents of isovaleric acid, isobutyric acid, and nonanoic acid increased.

[0068] In experimental group C, the acetic acid fermentation stage enhancement group, the content of each volatile component showed little change or even decreased compared to the control group, and the overall aroma enhancement effect was not significant. Therefore, *Hydrilla verrucosum* SQJ6 can be used to enhance the aroma of fermented vinegar, with significant effects, and inoculation enhancement is preferably carried out during the alcoholic fermentation stage.

[0069] Table 2. Volatile flavor components of Oleurotus erythrorhizon SQJ6 fortified fermented vinegar

[0070]

[0071]

[0072]

Claims

1. A fragrance-producing bacterium, identified as *Oleuronecti* (…). Heyndrickxia oleronia SQJ6 has been deposited at the China General Microbiological Culture Collection Center on October 25, 2023, with accession number CGMCC 28772.

2. The application of *Hydroxylon ammodendron* SQJ6 as described in claim 1 in fragrance production, wherein the fragrance comprises 3-ethyl-2,5-dimethylpyrazine, ethyl isovalerate, ethyl 2-methylbutyrate, 6-ethyl-2,3,5-trimethylpyrazine, and ethyl phenylacetate.

3. The application of the *Hydroxylolari* SQJ6 as described in claim 1 in enhancing the flavor of vinegar.

4. The application according to claim 3, characterized in that, During the alcoholic fermentation stage, Angel Yeast rice wine starter and Oleon Helicobacter SQJ6 culture medium are mixed in, followed by acetic acid fermentation.

5. The application according to claim 3, characterized in that, The application of *Hydroxylon olleron* SQJ6 in increasing the total amount of one or more volatile flavor compounds, including alcohols, esters, or aldehydes, in vinegar, wherein the alcohols are any one or more of isobutanol, phenethyl alcohol, and 2,3-butanediol; the esters are any one or more of isoamyl acetate, ethyl 2-methylbutyrate, ethyl isovalerate, diethyl succinate, ethyl phenylacetate, hexyl acetate, ethyl octanoate, ethyl acetate, isooctyl acetate, ethyl nonanoate, ethyl palmitate, phenylethyl acetate, ethyl benzoate, and γ-nonanolide; and the aldehydes are any one or more of 3-hydroxy-2-butanone, isovaleraldehyde, isophorone, furfural, phenylacetaldehyde, and 3,4-dimethylbenzaldehyde.

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