Glutamic acid bacterium m6 degrading 4-methylphenol and application thereof

Abstract

This invention relates to the field of bioengineering technology, specifically disclosing a strain of *Glutamicibacterium glutamicum* M6 that degrades 4-methylphenol and its applications. The *Glutamicibacterium glutamicum* M6 has the accession number CCTCC NO: M 2026206; its depositary institution is the China Center for Type Culture Collection; its accession name is *Glutamicibacter sp. M6*; its accession date is January 23, 2026; and its accession address is Wuhan University, Wuhan, China. This invention features adaptability to the production environment of fermented products and high degradation efficiency.

Description

Technical Field

[0001] This invention relates to the field of bioengineering technology, and in particular to a strain of glutamate bacillus M6 that degrades 4-methylphenol and its applications. Background Technology

[0002] 4-Methylphenol (p-cresol, abbreviated as PC), an aromatic compound, is an important synthetic precursor used in the manufacture of various chemical products, including synthetic resins, disinfectants, antioxidants, preservatives, fumigants, and explosives. However, due to its high toxicity to many higher organisms (including humans), it is also considered an environmental pollutant requiring strict control. This compound mainly originates from various industrial processes such as coal gasification and coal tar fractionation. Furthermore, in the natural environment, 4-methylphenol PC is also a byproduct of microbial metabolism of phenylalanine and tyrosine.

[0003] In addition, 4-methylphenol (PC), a volatile substance with a strong fecal odor, has been found in trace amounts in fermented foods such as cheese, wine, whiskey, and spirits. Although trace amounts of 4-methylphenol do not have a significant negative impact on the flavor of food, but rather become a distinctive flavor, its content in fermented bamboo shoots far exceeds its odor threshold. The odor threshold of this substance in 46% alcohol is 116.97 μg / L, and the odor threshold in water is 0.054 μg / L. This results in a noticeable off-odor in fermented bamboo shoots, which seriously restricts the development and sales of fermented bamboo shoot products.

[0004] Existing methods for eliminating the odor of bamboo shoots mainly involve physical control and chemical masking. These methods are not only difficult to implement and costly, but also prone to generating environmentally unfriendly secondary pollutants. Current research indicates that microbial methods for reducing environmental pollutants have received more widespread attention due to their low cost and environmental friendliness. However, resources for PC-degrading microorganisms remain insufficient, lacking food-safe strains suitable for the food industry. Furthermore, existing degrading strains are not adapted to the production environment of fermented products, resulting in insufficient degradation efficiency. Therefore, it is essential to screen for a highly efficient PC-degrading bacterium derived from fermented bamboo shoots to reduce the odor in fermented bamboo shoots. Summary of the Invention

[0005] In order to solve the above-mentioned technical problems in reducing the off-odor in fermented bamboo shoots, this invention provides a strain of glutamic acid bacillus M6 that degrades 4-methylphenol and its application. It has the characteristics of being able to adapt to the production environment of fermented products and having high degradation efficiency.

[0006] The first technical solution of the present invention is: a strain of *Glutamicibacterium glutamicum* M6 that degrades 4-methylphenol, wherein the accession number of *Glutamicibacterium glutamicum* M6 is CCTCC NO: M2026206; the depositary institution of *Glutamicibacterium glutamicum* M6 is the China Center for Type Culture Collection; the accession name of *Glutamicibacterium glutamicum* M6 is *Glutamicibacter sp. M6*; the accession date of *Glutamicibacterium glutamicum* M6 is January 23, 2026; and the accession address of *Glutamicibacterium glutamicum* M6 is Wuhan University, Wuhan, China. The strain of this invention is derived from fermented bamboo shoots and is an endogenous microorganism isolated and screened from the bamboo shoot fermentation system. It has co-evolved with the substrate over a long period and can naturally adapt to the temperature, pH, salinity, nutrient composition, and microbial interactions of the bamboo shoot fermentation environment. It can rapidly colonize and perform degradation functions without additional domestication or genetic modification. The strain is named *Glutamicibacter sp. M6*, clarifying its biological taxonomic position and serving as a basis for distinguishing it from other degrading strains. This confirms that the strain belongs to the food-grade safe strain category and can be legally used in the food processing field. This invention can directionally degrade 4-methylphenol, the main active ingredient in the off-odor of fermented bamboo shoots, eliminating or reducing the off-odor by directly reducing the content of 4-methylphenol. It can lower the concentration of 4-methylphenol in fermented bamboo shoots, improving the sensory quality of the product. The strain of this invention has the ability to metabolize 4-methylphenol as the sole carbon source, using enzymatic reactions to decompose it into harmless or low-harm small molecules, achieving complete degradation rather than physical adsorption or masking. The degradation efficiency is high, and no secondary pollutants are generated.

[0007] Preferably, the nucleotide sequence of the *Glutamicinus* M6 is shown in SEQ ID NO.1; the gene accession number of the *Glutamicinus* M6 is PZ945417.

[0008] The second technical solution of the present invention: a screening method for a strain of *Glutamicinus glutamate* M6 that degrades 4-methylphenol, comprising the following steps:

[0009] (S01) Take an appropriate amount of fermented bamboo shoots and grind them in sterile water until liquid flows out;

[0010] (S02) Take an appropriate amount of bamboo shoot extract from step (S01) and place it in liquid LB medium, and culture it at a temperature of 25-35℃ and a rotation speed of 150-300rpm.

[0011] (S03) Take an appropriate amount of the upper culture liquid from step (S02) and add it to liquid MM medium, and culture it at a temperature of 25-35℃ and a rotation speed of 150-300rpm.

[0012] (S04) Transfer the culture from step (S03) to a new liquid MM medium and repeat the culture;

[0013] (S05) After repeatedly transferring the culture from step (S04) 2-4 times, the final culture solution is diluted and spread onto LB solid agar plates for bacterial selection. This invention uses a sample solution containing endogenous microorganisms obtained from the target fermentation system. The microbial community attached to the surface and interior of bamboo shoot tissue is released into the liquid phase as a source for subsequent screening. This yields a rich original bacterial solution containing the target degrading bacterial species, preserving bacterial diversity. The liquid LB medium can non-selectively amplify the total microorganisms in the sample, ensuring the proliferation of all culturable microorganisms and increasing the bacterial population, thus increasing the probability of the target bacteria being selected from a low abundance state. The LB medium is a nutritionally complete enrichment medium that supports the growth of most heterotrophic bacteria, ensuring sufficient biomass of the degrading bacteria before subsequent selective pressure. This invention uses continuous transfer culture in liquid MM medium to directionally enrich microorganisms with 4-methylphenol degradation capabilities through nutrient selection pressure. In liquid MM medium, only strains that can grow using 4-methylphenol as the sole carbon source can proliferate, while those that cannot degrade this substrate will proliferate. The strains cannot grow due to the lack of carbon source, thus eliminating non-target bacteria and achieving targeted enrichment of degrading bacteria. Liquid MM medium contains no organic carbon source, with only 4-methylphenol added as the sole carbon source; only microorganisms carrying the corresponding degradation gene clusters can survive and proliferate. This invention purifies the target bacterial population through multiple rounds of subculturing. Each round of transfer involves inoculating fresh liquid MM medium at a fixed ratio, continuing to apply selection pressure to further eliminate non-target bacteria and poorly adapted strains. The relative abundance of target degrading bacteria in the community increases with each round. Multiple rounds of transfer and culture constitute a continuous enrichment process, gradually increasing the purity of the target bacterial population and laying the foundation for subsequent plate isolation. Diluting and plating onto LB solid plates allows for the separation of enriched mixed bacterial populations into single colonies, achieving pure culture isolation. Serial dilution allows individual cells to form independent single colonies on the plate, and picking single colonies yields pure cultures, resulting in degrading strains with a single genetic background.

[0014] Preferably, in step (S01), the mass of fermented bamboo shoots is 3 to 7 times the volume of sterile water. More preferably, the mass of fermented bamboo shoots is 4 to 6 times the volume of sterile water; or 5 times the volume of sterile water. This defined range of multiples allows for good control of sample concentration, avoiding insufficient target bacteria content due to excessive dilution, or interference from impurities due to excessive viscosity. It achieves a balance between bacterial enrichment and operational convenience, ensuring a sufficient initial amount of target bacteria for subsequent culture steps. The gradient concentration settings also accommodate operational flexibility in different laboratory and industrial settings.

[0015] Preferably, in step (S01), the mass-to-volume ratio of fermented bamboo shoots to sterile water is 7–15:1.5–3. More preferably, the mass-to-volume ratio is 8–14:1.7–2.8. Even more preferably, the mass-to-volume ratio is 9–13:1.9–2.6. Even more preferably, the mass-to-volume ratio is 10–12:2–2.4. Even more preferably, the mass-to-volume ratio is 11:2.2. In industrial applications, the mass of fermented bamboo shoots is expressed in kg, and the volume of sterile water is expressed in L; in laboratory applications, the mass of fermented bamboo shoots is expressed in g, and the volume of sterile water is expressed in mL.

[0016] Preferably, the grinding is carried out in an industrial grinding vessel or a laboratory mortar.

[0017] Preferably, in step (S02), the volume ratio of bamboo shoot extract to liquid LB medium is 1:20-30. More preferably, the volume ratio is 1:22-28. Even more preferably, the volume ratio is 1:25. In industrial applications, the volume units for bamboo shoot extract and liquid LB medium are L; in laboratory applications, the volume units are mL.

[0018] Preferably, in step (S02), the culture is carried out at a temperature of 28–32°C and a rotation speed of 170–280 rpm. More preferably, the culture is carried out at a temperature of 29–31°C and a rotation speed of 190–260 rpm. Even more preferably, the culture is carried out at a temperature of 30°C and a rotation speed of 220 rpm.

[0019] Preferably, the culture time in step (S02) is 2 to 4 days. More preferably, the culture time is 3 days. The limited culture conditions can provide suitable growth temperature and oxygen mass transfer conditions, simulate the temperature environment of the bamboo shoot fermentation system, ensure the activity of the strain, achieve the logarithmic growth phase of the strain, and reach the maximum biomass.

[0020] Preferably, in step (S03), the volume ratio of the upper culture liquid to the liquid MM medium is 1:20 to 30. More preferably, the volume ratio is 1:22 to 28. Even more preferably, the volume ratio is 1:25. In industrial applications, the volume units of the upper culture liquid and liquid MM medium are expressed in L; in laboratory applications, the volume units are expressed in mL.

[0021] Preferably, in step (S03), the culture is carried out at a temperature of 28–32°C and a rotation speed of 170–280 rpm. More preferably, the culture is carried out at a temperature of 29–31°C and a rotation speed of 190–260 rpm. Even more preferably, the culture is carried out at a temperature of 30°C and a rotation speed of 220 rpm.

[0022] Preferably, the culture time in step (S03) is 3 to 5 days. More preferably, the culture time is 4 days.

[0023] Preferably, the volume ratio of the culture to the new liquid MM medium in step (S04) is 1:20 to 30. More preferably, the volume ratio is 1:22 to 28. Even more preferably, the volume ratio is 1:25. In industrial applications, the volume of the culture to the new liquid MM medium is expressed in L; in laboratory applications, the volume is expressed in mL.

[0024] Preferably, the transfer is repeated 3 times in step (S05).

[0025] Preferably, the *Glutamicinus glutamate* M6 colonies on LB solid agar plates are round, raised, yellow, smooth without wrinkles, and have neat edges. Colony morphology serves as an external marker for preliminary screening and strain identification, aiding in the identification of target colonies during plate isolation and morphologically distinguishing them from other bacteria. This improves the efficiency of colony picking and reduces blind operations.

[0026] Preferably, the physiological and biochemical characteristics of *Glutamica melanobacterium* M6 are detected by Gram staining, methyl red (+), VP (volatile protein), urease, casein hydrolysis, catalase, and gelatin liquefaction. The results for Gram staining, methyl red (+), urease, and catalase are positive, while the results for VP, casein hydrolysis, and gelatin liquefaction are negative. Determining the metabolic type and taxonomic classification of the strain through multiple biochemical indicators helps identify the genus and species level of the strain, distinguishing it from other closely related strains, and is a typical characteristic for confirming that the strain belongs to the *Glutamica* genus.

[0027] Preferably, the utilization characteristics of the sole carbon source by *Glutamicinus glutamate* M6 were detected by testing for glucose, sucrose+, fructose, lactose, arabinose, acetate, citrate, starch, and mannose, respectively. All test results were positive. This method characterizes the breadth of carbon source utilization by the strain, verifies its metabolic diversity, assesses its adaptability in complex fermentation substrates, and confirms that *Glutamicinus glutamate* M6 has a broad range of carbon source utilization and the ability to compete for survival in the bamboo shoot fermentation system.

[0028] As a preferred method, the strains obtained by bacterial selection were identified by physiological and biochemical experiments and 16S rDNA sequence sequencing comparison with reference to Bergey's Manual of Systematic Bacteriology to determine the genus of the obtained strains.

[0029] As a preferred method, based on the 16S rDNA sequencing alignment results, the top 10 strain sequences with the highest similarity were selected and a phylogenetic tree was constructed using MEGA11. The Neighbor-Joining algorithm and 1000 Bootstrap statistical tests were used to construct the tree to determine the taxonomic position of *Glutamicibacter* M6. The taxonomic position of the strain was determined at the molecular level. Through 16S rRNA gene sequence alignment and phylogenetic analysis, the strain was precisely identified to the genus and species level, confirming it as a novel *Glutamicibacter* strain.

[0030] Preferably, the preparation method of fermented bamboo shoots in step (S01) is as follows: fresh bamboo shoots are peeled, cut into pieces, placed in sterilized headspace bottles, and incubated in an incubator at 20-30°C in the dark for 5-9 days. This prepares standardized inoculum material for screening experiments, simulating the natural fermentation process under controlled conditions to obtain a stable 4-methylphenol-producing microbial community, ensuring consistent starting material quality for each screening experiment.

[0031] Preferably, the amount of fresh bamboo shoots used is 100g to 700g, and the headspace bottle has a capacity of 150mL, 200mL, 250mL, 500mL, or 800mL. More preferably, the amount of fresh bamboo shoots used is 150g to 650g. More preferably, the amount of fresh bamboo shoots used is 200g to 600g. More preferably, the amount of fresh bamboo shoots used is 250g to 550g. More preferably, the amount of fresh bamboo shoots used is 300g to 500g. More preferably, the amount of fresh bamboo shoots used is 350g to 450g. More preferably, the amount of fresh bamboo shoots used is 400g.

[0032] Preferably, the pieces are cut into 0.5-2cm pieces. 3 Cut into pieces. More preferably, cut into 1-1.5cm pieces. 3 piece.

[0033] Preferably, the culture is carried out at 22–28°C in the dark for 6–8 days. More preferably, it is carried out at 25°C in the dark for 7 days.

[0034] Preferably, the *Glutamicinus glutamate* M6 was co-cultured in liquid MM medium containing 4-methylphenol under different conditions to detect its degradation ability of 4-methylphenol.

[0035] Preferably, 200–600 mg / L of 4-methylphenol is added to the liquid MM medium. More preferably, 250–550 mg / L of 4-methylphenol is added to the liquid MM medium. More preferably, 300–500 mg / L of 4-methylphenol is added to the liquid MM medium. More preferably, 350–450 mg / L of 4-methylphenol is added to the liquid MM medium. More preferably, 400 mg / L of 4-methylphenol is added to the liquid MM medium.

[0036] Preferably, the different conditions are different temperatures, different pH values, different 4-methylphenol concentrations, and different incubation times.

[0037] As a preferred method, the cells were co-cultured at temperatures of 16℃, 20℃, 25℃, 30℃ and 37℃, respectively, and the growth and degradation capacity for 250 mg / L 4-methylphenol were tested after 24 h.

[0038] As a preferred method, the cells were co-cultured at pH values ​​of 4, 5, 6, 7, 8, 9, and 10, a temperature of 30°C, and a rotation speed of 220 rpm, respectively, and the growth and degradation capacity for 250 mg / L 4-methylphenol were detected after 24 h.

[0039] As a preferred method, the plants were co-cultured at 30°C and 220 rpm, and the growth was assessed after 24 hours, as well as their degradation capacity for 4-methylphenol at different concentrations of 200, 300, 400, 500 and 600 mg / L.

[0040] As a preferred method, the strain was co-cultured at 30℃ and 220rpm, and its growth and degradation ability at a concentration of 250mg / L 4-methylphenol were detected at 8h, 16h, 24h, 32h, and 40h. This comprehensively characterized the degradation performance and optimal working conditions of the M6 ​​strain, determining the optimal temperature, pH range, tolerance concentration, and degradation kinetics for 4-methylphenol degradation, providing process parameters for subsequent industrial applications.

[0041] The third technical solution of this invention: the application of a strain of *Glutamicinus glutamate* M6 that degrades 4-methylphenol in reducing or eliminating the off-odor of fermented bamboo shoots. This strain can completely degrade 250 mg / L of 4-methylphenol (PC) within 24 hours, and also exhibits strong low-temperature resistance, showing a certain degradation effect on high concentrations of 4-methylphenol (PC). The strain was screened from edible fermented bamboo shoots; currently, no related strains have been reported, and it has the ability to degrade off-odor substances in bamboo shoots.

[0042] As a preferred method, the degradation of 4-methylphenol in bamboo shoots by *Bacillus glutamate* M6 after culturing at 30°C for 7 days was determined.

[0043] Preferably, the bamboo shoots are fresh bamboo shoots, fermented bamboo shoots, or fermented bamboo shoots.

[0044] The present invention has the following beneficial effects:

[0045] (1) The strain is derived from fermented bamboo shoots. It is an endogenous microorganism isolated and screened from the bamboo shoot fermentation system. It has long co-evolved with the substrate and can naturally adapt to the temperature, pH, salinity, nutrient composition and microbial community interaction of the bamboo shoot fermentation environment. It can quickly colonize and play a degradation function without additional domestication or genetic modification.

[0046] (2) The strain was named Glutamicibacter M6 and its preservation name was Glutamicibacter sp.M6. The biological classification status of the strain was clarified. As a basis for identification to distinguish it from other degrading strains, it was determined that the strain belongs to the category of food-grade safe strains and can be legally used in the food processing field.

[0047] (3) It can directionally degrade the main active ingredient of fermented bamboo shoot odor, 4-methylphenol, and eliminate or reduce the odor by directly reducing the content of 4-methylphenol. It can reduce the concentration of 4-methylphenol in fermented bamboo shoot and improve the sensory quality of the product.

[0048] (4) The strain has the ability to metabolize 4-methylphenol as the sole carbon source, and uses enzymatic reactions to decompose it into harmless or low-harm small molecules, achieving complete degradation rather than physical adsorption or masking. The degradation efficiency is high and no secondary pollutants are generated.

[0049] (5) The strain can completely degrade 250 mg / L of 4-methylphenol PC within 24 hours, and has strong resistance to low temperature. It has a certain degradation effect on high concentration of 4-methylphenol PC. The strain was screened from edible fermented bamboo shoots. There are currently no reports on related strains. It has the ability to degrade odor substances in bamboo shoots. Attached Figure Description

[0050] Figure 1 This is a colony morphology diagram of Bacillus glutamate M6 of the present invention on LB plates;

[0051] Figure 2 This is a Gram staining result of Bacillus glutamate M6 in this invention;

[0052] Figure 3 This is the sequence phylogenetic tree of Bacillus glutamate M6 of the present invention;

[0053] Figure 4 This is a graph showing the growth and degradation of Bacillus glutamicum M6 at different temperatures and 250 mg / L pc.

[0054] Figure 5This is a diagram showing the growth and degradation of Bacillus glutamicum M6 at different pH levels (250 mg / L pc).

[0055] Figure 6 This is a diagram showing the degradation of different concentrations of PC by Bacillus glutamate M6 and the growth of M6.

[0056] Figure 7 This is a graph showing the growth and degradation of Bacillus glutamate M6 of the present invention at 250 mg / L pc within 40 h;

[0057] Figure 8 This is a graph showing the degradation capacity of PC in bamboo shoots after 7 days following the addition of Bacillus glutamate M6 to bamboo shoots according to the present invention.

[0058] Figure 9 This is a graph showing the degradation capacity of *C. glutamate* M6 in fresh bamboo shoots after 7 days. Detailed Implementation

[0059] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the present invention.

[0060] A strain of *Glutamicibacter* M6 that degrades 4-methylphenol has been identified. The accession number for *Glutamicibacter* M6 is CCTCC NO: M2026206; the depositary institution is the China Center for Type Culture Collection; the accession name is *Glutamicibacter sp. M6*; the deposit date is January 23, 2026; and the deposit address is Wuhan University, Wuhan, China. The nucleotide sequence of *Glutamicibacter* M6 is shown in SEQ ID NO.1; the accession number is PZ945417.

[0061] A screening method for a strain of *Glutamicinus glutamate* M6 that degrades 4-methylphenol includes the following steps:

[0062] (S01) Take an appropriate amount of fermented bamboo shoots and add them to sterile water for grinding until liquid flows out; in step (S01), the mass of fermented bamboo shoots is 3 to 7 times the volume of sterile water; the mass of fermented bamboo shoots is 4 to 6 times the volume of sterile water; the mass of fermented bamboo shoots is 5 times the volume of sterile water; the mass-to-volume ratio of fermented bamboo shoots to sterile water in step (S01) is 7 to 15: 1.5 to 3; the mass-to-volume ratio is 8 to 14: 1.7 to 2.8; the mass-to-volume ratio is 9 to 13: 1.9 to 2.6; the mass-to-volume ratio is 10 to 12: 2 to 2.4; the mass-to-volume ratio is 11: 2.2; in industry, the mass unit of fermented bamboo shoots is kg, and the volume unit of sterile water is L; in the laboratory, the mass unit of fermented bamboo shoots is g, and the volume unit of sterile water is mL; grinding is carried out in an industrial grinding container or a laboratory mortar;

[0063] Step (S01) The preparation method of fermented bamboo shoots is as follows: Take fresh bamboo shoots, peel them, cut them into pieces, place them in sterilized headspace bottles, and incubate them in an incubator at 20-30℃ in the dark for 5-9 days; the amount of fresh bamboo shoots used is 100g-700g, and the headspace bottle specifications are 150mL, 200mL, 250mL, 500mL, or 800mL; the amount of fresh bamboo shoots used is 150g-650g; the amount of fresh bamboo shoots used is 200g-600g; the amount of fresh bamboo shoots used is 250g-550g; the amount of fresh bamboo shoots used is 300g-500g; the amount of fresh bamboo shoots used is 350g-450g; the amount of fresh bamboo shoots used is 400g; the pieces are cut into 0.5-2cm pieces. 3 Cut into pieces; cut into 1-1.5cm pieces. 3 Blocks; cultured in the dark at 22–28℃ for 6–8 days; cultured in the dark at 25℃ for 7 days;

[0064] (S02) Take an appropriate amount of the bamboo shoot extract from step (S01) and place it in liquid LB medium, and incubate at a temperature of 25–35℃ and a rotation speed of 150–300 rpm; the volume ratio of bamboo shoot extract to liquid LB medium in step (S02) is 1:20–30; the volume ratio of bamboo shoot extract to liquid LB medium is 1:22–28; the volume ratio of bamboo shoot extract to liquid LB medium is 1:25; in industrial applications, the volume units of bamboo shoot extract and liquid LB medium are in L; in laboratory applications, the volume units of bamboo shoot extract and liquid LB medium are in mL; in step (S02), incubate at a temperature of 28–32℃ and a rotation speed of 170–280 rpm; incubate at a temperature of 29–31℃ and a rotation speed of 190–260 rpm; incubate at a temperature of 30℃ and a rotation speed of 220 rpm; the incubation time in step (S02) is 2–4 days; the incubation time is 3 days;

[0065] (S03) Take an appropriate amount of the upper culture liquid from step (S02) and add it to liquid MM medium. Incubate at 25-35℃ and 150-300 rpm. The formula of the liquid MM basal medium is: K2HPO4 4.8 g / L, KH2PO4 1.2 g / L, NH4NO3 1.0 g / L, MgSO4·7H2O 0.2 g / L, CaCl2 0.02 g / L, and trace element stock solution 1 mL / L. The composition of the trace element stock solution is: FeSO4·7H2O 1 g, MnSO4·H2O 0.5 g, ZnSO4·7H2O 0.5 g. 0.5g, distilled water to a final volume of 1L, adjust the initial pH of the culture medium to 7.0, autoclave at 121℃ for 20min; add filtered sterilized 4-methylphenol before use to prepare the target working concentration; add an additional 15-20g / L agar to solid MM medium; in step (S03), the volume ratio of the upper culture liquid to the liquid MM medium is 1:20-30; the volume ratio of the upper culture liquid to the liquid MM medium is 1:22-28; the volume ratio of the upper culture liquid to the liquid MM medium... The ratio is 1:25; the volume units of the industrial supernatant culture liquid and liquid MM culture medium are in L; the volume units of the laboratory supernatant culture liquid and liquid MM culture medium are in mL; in step (S03), the culture is carried out at a temperature of 28-32℃ and a rotation speed of 170-280 rpm; at a temperature of 29-31℃ and a rotation speed of 190-260 rpm; at a temperature of 30℃ and a rotation speed of 220 rpm; the culture time in step (S03) is 3-5 days; the culture time is 4 days;

[0066] The liquid MM medium was autoclaved at 121°C for 20 minutes, cooled to room temperature, and then 4-methylphenol stock solution (filtered and sterilized through a 0.22 μm filter membrane) was added under aseptic conditions to prepare the target working concentration. 200–600 mg / L of 4-methylphenol was added to the liquid MM medium; 250–550 mg / L of 4-methylphenol was added to the liquid MM medium; 300–500 mg / L of 4-methylphenol was added to the liquid MM medium; 350–450 mg / L of 4-methylphenol was added to the liquid MM medium; and 400 mg / L of 4-methylphenol was added to the liquid MM medium.

[0067] (S04) Transfer the culture from step (S03) to a new liquid MM medium and repeat the culture; the volume ratio of the culture to the new liquid MM medium in step (S04) is 1:20-30; the volume ratio of the culture to the new liquid MM medium is 1:22-28; the volume ratio of the culture to the new liquid MM medium is 1:25; in industrial applications, the volume unit of the culture to the new liquid MM medium is L; in laboratory applications, the volume unit of the culture to the new liquid MM medium is mL.

[0068] (S05) After transferring the culture in step (S04) 2 to 4 times, dilute the final culture solution and spread it on LB solid plate medium for picking bacteria; repeat the transfer 3 times in step (S05);

[0069] The colonies of *Glutamicinus glutamate* M6 on LB agar plates are round, raised, yellow, smooth, without wrinkles, and have regular edges. The physiological and biochemical characteristics of *Glutamicinus glutamate* M6 were detected using Gram staining, methyl red (+), VP (volatile protein), urease, casein hydrolysis, catalase, and gelatin liquefaction. Gram staining, methyl red (+), urease, and catalase were positive, while VP, casein hydrolysis, and gelatin liquefaction were negative. The utilization characteristics of *Glutamicinus glutamate* M6 by its single carbon source were detected using glucose, sucrose (+), fructose, lactose, arabinose, acetate, citrate, starch, and mannose; all results were positive.

[0070] The selected bacterial strains were identified through physiological and biochemical experiments and 16S rDNA sequence alignment according to Bergey's Manual of Systematic Bacteriology to determine their genus. Based on the 16S rDNA sequencing alignment results, the 16S rRNA gene of *Glutamica glutamicum* strain M6 was amplified by PCR using universal bacterial primers 27F / 1492R. The amplified product was sequenced to obtain the 16S rDNA sequence of *Glutamica glutamicum* strain M6. The sequencing results were submitted to the NCBI database for BLAST comparison. The top 10 strain sequences with the highest similarity were selected and a phylogenetic tree was constructed using MEGA11. The Neighbor-Joining algorithm and 1000 Bootstrap statistical tests were used to construct the phylogenetic tree to determine the taxonomic position of *Glutamica glutamicum* M6. Physiological and biochemical experiments were conducted according to *Bergey's Manual of Systematic Bacteriology* using commercially available bacterial physiological and biochemical identification tubes. The reaction results were observed and recorded after incubation at 30°C for 24–48 hours. The single carbon source utilization experiment used liquid MM basal medium, with the corresponding carbon source added to a final concentration of 1 g / L, and cultured at 30°C with shaking at 220 rpm. The OD was used to determine the phylogenetic position of *Glutamica glutamicum* M6. 600 To determine the growth of the bacterial strain, growth is recorded as positive "+", and no growth is recorded as negative "-".

[0071] The detection method for 4-methylphenol was as follows: High-performance liquid chromatography (HPLC). For the preparation of liquid culture medium samples, the culture medium was centrifuged at 12000 rpm for 10 min, the supernatant was collected, and filtered through a 0.22 μm organic filter membrane. For the preparation of bamboo shoot samples, bamboo shoot tissue was collected, and ethyl acetate was added as the extraction organic solvent (1 g:5 mL ratio). The mixture was vortexed for 3 min, ultrasonically extracted at 200 W for 20 min, centrifuged at 12000 rpm for 10 min, and the upper organic phase was collected and filtered through a 0.22 μm organic phase filter membrane for HPLC detection. The HPLC conditions were: C18 reversed-phase column, methanol-water mobile phase, and UV detector at 277 nm. The external standard method for quantification involved establishing a standard curve using gradient concentrations of 4-methylphenol standards, calculating the 4-methylphenol concentration in the sample, and determining the degradation rate (%) as follows: (C0 - C...). t ) / C0×100%, where C0 is the measured concentration of 4-methylphenol in the blank control sample without inoculation, and C t To determine the residual concentration of 4-methylphenol in samples after inoculation and incubation for time t, all concentrations were determined under the same extraction and HPLC conditions. *Glutamicinus glutamate* M6 was co-cultured in liquid MM medium containing 4-methylphenol under different conditions to assess its degradation ability. These different conditions included different temperatures, different pH values, different 4-methylphenol concentrations, and different incubation times.

[0072] The cells were co-cultured at 16℃, 20℃, 25℃, 30℃ and 37℃ respectively, and the growth and degradation ability of 250 mg / L 4-methylphenol were detected after 24 h.

[0073] The cells were co-cultured at pH values ​​of 4, 5, 6, 7, 8, 9 and 10, temperatures of 30°C and rotation speeds of 220 rpm, respectively, and the growth and degradation capacity for 250 mg / L 4-methylphenol were assessed after 24 h.

[0074] The cells were co-cultured at 30℃ and 220rpm, and the growth was detected after 24h, as well as the degradation capacity of 4-methylphenol at different concentrations of 200, 300, 400, 500 and 600 mg / L.

[0075] The cells were co-cultured at 30℃ and 220rpm, and the growth and degradation capacity of 250mg / L 4-methylphenol were detected at 8h, 16h, 24h, 32h and 40h.

[0076] The application of a strain of glutamate bacillus M6 that degrades 4-methylphenol in reducing or eliminating the off-flavor of fermented bamboo shoots was investigated. The degradation of 4-methylphenol in bamboo shoots by glutamate bacillus M6 after culturing at 30℃ for 7 days was determined. The bamboo shoots included both fresh and fermented bamboo shoots.

[0077] Example 1: A screening method for a strain of *Glutamicinus glutamate* M6 that degrades 4-methylphenol, comprising the following steps:

[0078] (S01) Take an appropriate amount of fermented bamboo shoots and add them to sterile water for grinding until liquid flows out; the mass of fermented bamboo shoots in step (S01) is 3 times the volume of sterile water; grinding is carried out in a laboratory mortar;

[0079] Step (S01) The preparation method of fermented bamboo shoots is as follows: peel fresh bamboo shoots, cut them into pieces, place them in a sterilized headspace bottle, and incubate them in an incubator at 20℃ in the dark for 9 days; the amount of fresh bamboo shoots used is 100g, and the headspace bottle size is 150mL; the pieces are cut into 0.5cm pieces. 3 Blocks; cultured in the dark at 22℃ for 8 days;

[0080] (S02) Take an appropriate amount of bamboo shoot extract from step (S01) and place it in liquid LB medium, and incubate at 25°C and 150 rpm. The volume ratio of bamboo shoot extract to liquid LB medium in step (S02) is 1:20. The volume units of bamboo shoot extract and liquid LB medium in the laboratory are in mL. The incubation time in step (S02) is 4 days.

[0081] (S03) Take an appropriate amount of the upper culture liquid from step (S02) and add it to liquid MM medium. Incubate at 25°C and 150 rpm. The volume ratio of the upper culture liquid to the liquid MM medium in step (S03) is 1:20. The volume units of the upper culture liquid and liquid MM medium in the laboratory are in mL. The incubation time in step (S03) is 5 days.

[0082] Add 200 mg / L of 4-methylphenol to liquid MM medium;

[0083] (S04) Transfer the culture from step (S03) to a new liquid MM medium and repeat the culture; the volume ratio of the culture in step (S04) to the new liquid MM medium is 1:20; the volume of the culture and the new liquid MM medium in the laboratory is in mL.

[0084] (S05) After transferring the culture from step (S04) twice, dilute the final culture solution and spread it onto LB solid plate medium for bacterial picking;

[0085] The colonies of *Glutamicinus glutamate* M6 on LB agar plates are round, raised, yellow, smooth, without wrinkles, and have regular edges. The physiological and biochemical characteristics of *Glutamicinus glutamate* M6 were detected using Gram staining, methyl red (+), VP (volatile protein), urease, casein hydrolysis, catalase, and gelatin liquefaction. Gram staining, methyl red (+), urease, and catalase were positive, while VP, casein hydrolysis, and gelatin liquefaction were negative. The utilization characteristics of *Glutamicinus glutamate* M6 by its single carbon source were detected using glucose, sucrose (+), fructose, lactose, arabinose, acetate, citrate, starch, and mannose; all results were positive.

[0086] The strains obtained by bacterial selection were identified by physiological and biochemical experiments and 16S rDNA sequence alignment according to Bergey's Manual of Systematic Bacteriology to determine the genus of the obtained strains. Based on the 16S rDNA sequence alignment results, the top 10 strains with the highest similarity were selected and a phylogenetic tree was constructed using MEGA11. The Neighbor-Joining algorithm and 1000 Bootstrap statistical tests were used to construct the tree to determine the taxonomic position of Bacillus glutamicum M6.

[0087] *Glutamicinus M6* was co-cultured in liquid MM medium containing 4-methylphenol under different conditions to detect its degradation ability of 4-methylphenol. The different conditions included different temperatures, different pH values, different 4-methylphenol concentrations, and different incubation times. Specifically,

[0088] The cells were co-cultured at 16℃, 20℃, 25℃, 30℃ and 37℃ respectively, and the growth and degradation ability of 250 mg / L 4-methylphenol were detected after 24 h.

[0089] The cells were co-cultured at pH values ​​of 4, 5, 6, 7, 8, 9 and 10, temperatures of 30°C and rotation speeds of 220 rpm, respectively, and the growth and degradation capacity for 250 mg / L 4-methylphenol were assessed after 24 h.

[0090] The cells were co-cultured at 30℃ and 220rpm, and the growth was detected after 24h, as well as the degradation capacity of 4-methylphenol at different concentrations of 200, 300, 400, 500 and 600 mg / L.

[0091] The cells were co-cultured at 30℃ and 220rpm, and the growth and degradation capacity of 250mg / L 4-methylphenol were detected at 8h, 16h, 24h, 32h and 40h.

[0092] Example 2: This example is basically the same as Example 1, except that the mass of fermented bamboo shoots in step (S01) is 7 times the volume of sterile water; the mass of fermented bamboo shoots in the laboratory is expressed in g, and the volume of sterile water is expressed in mL; the preparation method of fermented bamboo shoots in step (S01) is as follows: fresh bamboo shoots are peeled, cut into pieces, placed in a sterile headspace bottle, and placed in an incubator for 5 days in the dark at 30°C; the amount of fresh bamboo shoots used is 700g, and the headspace bottle size is 800mL; the pieces are cut into 2cm pieces. 3 (S02) Take an appropriate amount of the bamboo shoot liquid from step (S01) and place it in liquid LB medium, and culture it at 35℃ and 300 rpm. The volume ratio of the bamboo shoot liquid to the liquid LB medium in step (S02) is 1:30. The culture time in step (S02) is 2 days. (S03) Take an appropriate amount of the upper culture liquid from step (S02) and add it to liquid MM medium, and culture it at 35℃ and 300 rpm. The volume ratio of the upper culture liquid to the liquid MM medium in step (S03) is 1:30. The culture time in step (S03) is 3 days. Add 600 mg / L of 4-methylphenol to the liquid MM medium. The volume ratio of the culture in step (S04) to the new liquid MM medium is 1:30. (S05) After transferring the culture in step (S04) 4 times, dilute the final culture solution and spread it on LB solid plate medium for bacterial picking.

[0093] Example 3: This example is basically the same as Example 1, except that the mass of fermented bamboo shoots in step (S01) is 4 times the volume of sterile water; the mass of fermented bamboo shoots in the laboratory is expressed in g, and the volume of sterile water is expressed in mL; the preparation method of fermented bamboo shoots in step (S01) is as follows: 150g of fresh bamboo shoots are used, the headspace bottle is 200mL, and the shoots are cut into 1cm pieces. 3 The culture was carried out in the dark at 25°C for 7 days; the volume ratio of bamboo shoot extract to liquid LB medium in step (S02) was 1:22; the culture was carried out at 28°C and 170 rpm in step (S02); the culture time in step (S02) was 3 days; the volume ratio of the upper culture liquid to liquid MM medium in step (S03) was 1:22; the culture was carried out at 28°C and 170 rpm in step (S03); the culture time in step (S03) was 4 days; 250 mg / L of 4-methylphenol was added to the liquid MM medium; the volume ratio of the culture to fresh liquid MM medium in step (S04) was 1:22; the transfer was repeated 3 times in step (S05).

[0094] Example 4: This example is basically the same as Example 1, except that the mass of fermented bamboo shoots in step (S01) is 6 times the volume of sterile water; the preparation method of fermented bamboo shoots in step (S01) is as follows: 650g of fresh bamboo shoots are used, the headspace bottle is 800mL, and the shoots are cut into 1.5cm pieces. 3 The culture was carried out in the dark at 25℃ for 7 days; the volume ratio of bamboo shoot liquid to liquid LB medium in step (S02) was 1:28; the culture was carried out at 31℃ and 260 rpm in step (S02); the culture time in step (S02) was 3 days; the volume ratio of the upper culture liquid to liquid MM medium in step (S03) was 1:28; the culture time in step (S03) was 4 days at 31℃ and 260 rpm; 550 mg / L of 4-methylphenol was added to the liquid MM medium; the volume ratio of the culture to the new liquid MM medium in step (S04) was 1:28; the transfer was repeated 3 times in step (S05).

[0095] Example 5: This example is basically the same as Example 1, except that the mass of fermented bamboo shoots in step (S01) is 5 times the volume of sterile water; the preparation method of fermented bamboo shoots in step (S01) is as follows: the amount of fresh bamboo shoots used is 400g; the headspace bottle is 500mL, and the shoots are cut into 1cm pieces. 3 The blocks were cultured in the dark at 25℃ for 7 days; in step (S02), the volume ratio of bamboo shoot liquid to liquid LB medium was 1:25; in step (S02), the culture was carried out at 30℃ and 220 rpm for 3 days; in step (S03), the volume ratio of the upper culture liquid to liquid MM medium was 1:25; in step (S03), the culture was carried out at 30℃ and 220 rpm for 4 days; 400 mg / L of 4-methylphenol was added to the liquid MM medium; in step (S04), the volume ratio of the culture to the new liquid MM medium was 1:25; in step (S05), the transfer was repeated 3 times.

[0096] Example 6: Application of *Glutamicinus glutamate* M6 strain that degrades 4-methylphenol in reducing or eliminating off-flavors in fermented bamboo shoots. The degradation of 4-methylphenol in bamboo shoots by *Glutamicinus glutamate* M6 was determined after culturing at 30°C for 7 days. The bamboo shoots included both fresh and fermented bamboo shoots. The activated *Glutamicinus glutamate* M6 bacterial culture was taken, and the OD value of the bacterial cells was adjusted. 600=1.0 as seed culture; the experimental group was inoculated with Bacillus glutamicum M6 seed culture at a mass-to-volume ratio of 5% (v / w) into the bamboo shoot samples; the inoculation amount of the high-dose experimental group was increased to 10% (v / w); the blank control group was inoculated with an equal volume of sterile physiological saline; the bamboo shoot samples were placed in sealed containers and incubated at 30℃ for 7 days; after the incubation, samples were taken, and the residual amount of 4-methylphenol in the bamboo shoot matrix was determined according to the 4-methylphenol detection method. The detection results are as follows. Figure 8 and Figure 9 As shown, the residual amount of pc in the stinky bamboo shoot control group was 41.6 μg / g; the residual amount of pc in the 5% (v / w) inoculated group with Bacillus glutamate M6 was 30.4 μg / g; the residual amount of pc in the 10% (v / w) inoculated group with 2 times the amount of Bacillus glutamate M6 was 22.3 μg / g; the residual amount of pc in the fresh bamboo shoot control group was 1075 μg / g; and the residual amount of pc in the fresh bamboo shoot group with 5% (v / w) inoculated group with Bacillus glutamate M6 was 512 μg / g.

[0097] Example 7: Screening and identification of Bacillus glutamicum M6:

[0098] (1) To prepare fermented bamboo shoots, take fresh bamboo shoots, cut them into pieces, put them into sterilized headspace bottles, and incubate them in a 25℃ incubator for 7 days.

[0099] (2) Screening: Take 10g of fermented bamboo shoots, add 2mL of sterile water, grind them in a mortar until liquid flows out, and take 2ml of the bamboo shoot liquid into 50ml of liquid LB medium. Incubate at 30℃ and 220rpm for 3 days. After 3 days of incubation, take 2mL of the upper liquid and add it into 50mL of liquid MM medium. Incubate at 30℃ and 220r / min for 4 days. Then take 2mL of the culture and transfer it to a new 50mL of liquid MM medium. Repeat the above culture process. After transferring 3 times, dilute the final culture solution and spread it on LB solid plate medium. Then carry out the step of picking bacteria.

[0100] (3) such as Figure 1 As shown, the colonies of Bacillus glutamate M6 on LB plates are round, raised, yellow, smooth without wrinkles, and have neat edges.

[0101] (4) Physiological and biochemical experiments and utilization characteristics of unique carbon sources: Physiological and biochemical experiments were performed on *Glutamicinus glutamate* M6, and the results are shown in Table 1. In addition, its utilization characteristics of eight unique carbon sources were tested, and the results are shown in Table 2. Furthermore, in Tables 1 and 2, "+" indicates a positive result, and "-" indicates a negative result. Gram staining results are shown below. Figure 2 As shown, purple represents Bacillus glutamate M6.

[0102] Table 1: Physiological and biochemical results of Bacillus glutamicum M6

[0103] Biochemical test items Results of Bacillus glutamicum M6 strain Gram staining + Methyl Red+ + VP - Urease + Casein hydrolysis - catalase + Gelatin liquefaction -

[0104] Table 2: Growth results of Bacillus glutamicum M6 with only one carbon source

[0105] Types of carbon sources Growth results of Bacillus glutamicum M6 strain glucose + Sucrose+ + fructose + lactose + Arabic sugar + Acetate + citrate + starch + Mannose +

[0106] The nucleotide sequence of the 16S rDNA of this strain Glutamicibacter sp. M6 is shown in SEQ ID NO.1, and its accession number in the NCBI GenBank database is PZ945417, specifically:

[0107]

[0108] The sequence was submitted to the NCBI database for BLAST alignment. Based on the 16S rDNA sequencing alignment results, the top 10 strain sequences with the highest similarity were selected and a phylogenetic tree was constructed using MEGA11. The Neighbor-Joining algorithm and 1000 Bootstrap statistical tests were used to construct the phylogenetic tree to determine the taxonomic position of *Glutamicinus glutamate* M6. The phylogenetic tree of *Glutamicinus glutamate* M6 is shown below. Figure 3 .

[0109] The Glutamicibacter M6 was identified as Glutamicibacter sp., with accession number CCTCC NO: M2026206, accession date: January 23, 2026, depositary institution: China Center for Type Culture Collection, address: Wuhan University, Wuhan, China.

[0110] Determination of the ability of Bacillus glutamicum M6 to degrade PC under different conditions:

[0111] like Figure 4 As shown, *Bacillus glutamicum* M6 exhibits good degradation ability at both 25℃ and 30℃, achieving complete degradation within 24 hours, while the degradation performance is worst at 37℃, with only 13.88% degradation.

[0112] like Figure 5 As shown, *Bacillus glutamicum* M6 exhibits good degradation effects on *pc* at pH 6, 7, and 8, with the best degradation effect at pH 8 reaching 82.13%, while the degradation effects are poor at pH 4 and 5, at 26.23% and 13.79%, respectively.

[0113] like Figure 6 As shown, Glutamic acid bacteria M6 exhibited the best degradation effect and growth effect on 200 mg / L PC. The degradation ability decreased with higher concentrations, indicating that PC has a certain degree of toxicity to the strain.

[0114] like Figure 7 As shown, when 250 mg / L of pc is used as the sole carbon source, the growth rate of Bacillus glutamate M6 is the fastest and the degradation rate is the strongest in the first 0-24 hours. However, the degradation rate slows down after 24 hours and is completely degraded at 40 hours.

[0115] like Figure 8 and Figure 9 As shown, when Glutamicin M6 was added to fresh bamboo shoots and stinky bamboo shoots, the PC content in both types of bamboo shoots decreased to some extent after 7 days.

Claims

1. The application of a strain of *Bacillus glutamate* M6 that degrades 4-methylphenol in reducing or eliminating the off-flavor of fermented bamboo shoots, characterized by: The accession number of the *Glutamicinus* M6 is CCTCC NO: M 2026206; the depositary institution of the *Glutamicinus* M6 is the China Center for Type Culture Collection; the accession name of the *Glutamicinus* M6 is *Glutamicibacters p. M6*; the deposit date of the *Glutamicinus* M6 is January 23, 2026; and the deposit address of the *Glutamicinus* M6 is Wuhan University, Wuhan, China.

2. The application of the *Glutamicinus glutamate* M6 strain that degrades 4-methylphenol according to claim 1 in reducing or eliminating the off-flavor of fermented bamboo shoots, characterized in that: The nucleotide sequence of the *Glutamicinus* M6 is shown in SEQ ID NO.1; the gene accession number of the *Glutamicinus* M6 is PZ945417.

3. The application of the *Bacillus glutamate* M6 strain that degrades 4-methylphenol according to claim 1 in reducing or eliminating the off-flavor of fermented bamboo shoots, characterized in that: The degradation of 4-methylphenol in bamboo shoots by Bacillus glutamate M6 after culturing at 30℃ for 7 days was determined.

4. The application of the *Glutamicinus glutamate* M6 strain that degrades 4-methylphenol according to claim 1 in reducing or eliminating the off-flavor of fermented bamboo shoots, characterized in that: The screening method for a strain of glutamate bacillus M6 that degrades 4-methylphenol. Includes the following steps, (S01) Take an appropriate amount of fermented bamboo shoots and grind them in sterile water until liquid flows out; (S02) Take an appropriate amount of bamboo shoot extract from step (S01) and place it in liquid LB medium, and culture it at a temperature of 25-35℃ and a rotation speed of 150-300rpm. (S03) Take an appropriate amount of the upper culture liquid from step (S02) and add it to liquid MM medium, and culture it at a temperature of 25-35℃ and a rotation speed of 150-300rpm. (S04) Transfer the culture from step (S03) to a new liquid MM medium and repeat the culture; (S05) After transferring the culture from step (S04) 2 to 4 times, dilute the final culture solution and spread it onto LB solid plate medium for bacterial picking.

5. The application of the *Glutamicinus glutamate* M6 strain that degrades 4-methylphenol according to claim 4 in reducing or eliminating the off-flavor of fermented bamboo shoots, characterized in that: In step (S01), the mass of fermented bamboo shoots is 3 to 7 times the volume of sterile water; in industry, the mass of fermented bamboo shoots is measured in kg and the volume of sterile water is measured in L; in the laboratory, the mass of fermented bamboo shoots is measured in g and the volume of sterile water is measured in mL; the grinding is carried out in an industrial grinding container or a laboratory mortar. In step (S02), the volume ratio of bamboo shoot extract to liquid LB medium is 1:20-30; in industry, the volume units of bamboo shoot extract and liquid LB medium are in L; in the laboratory, the volume units of bamboo shoot extract and liquid LB medium are in mL; in step (S02), the culture is carried out at a temperature of 28-32℃ and a rotation speed of 170-280 rpm; the culture time in step (S02) is 2-4 days.

6. The application of the *Glutamicinus glutamate* M6 strain that degrades 4-methylphenol according to claim 4 in reducing or eliminating the off-flavor of fermented bamboo shoots, characterized in that: In step (S03), the volume ratio of the upper culture liquid to the liquid MM medium is 1:20-30; in industrial applications, the volume units of the upper culture liquid and liquid MM medium are in liters (L); in laboratory applications, the volume units of the upper culture liquid and liquid MM medium are in milliliters (mL); in step (S03), the culture is carried out at a temperature of 28-32°C and a rotation speed of 170-280 rpm; the culture time in step (S03) is 3-5 days. In step (S04), the volume ratio of the culture to the new liquid MM medium is 1:20-30; in industry, the volume of the culture to the new liquid MM medium is expressed in L; in the laboratory, the volume of the culture to the new liquid MM medium is expressed in mL; 200-600 mg / L of 4-methylphenol is added to the liquid MM medium.

7. The application of the *Glutamicinus glutamate* M6 strain that degrades 4-methylphenol according to claim 1 in reducing or eliminating the off-flavor of fermented bamboo shoots, characterized in that: The colonies of *Glutamicinus M6* on LB solid agar plates are round, raised, yellow, smooth without wrinkles, and have neat edges. The physiological and biochemical characteristics of *Glutamica glutamate* M6 were detected by Gram staining, methyl red+, VP, urease, casein hydrolysis, catalase, and gelatin liquefaction. The results of Gram staining, methyl red+, urease, and catalase were positive, while the results of VP, casein hydrolysis, and gelatin liquefaction were negative. The method for detecting the utilization characteristics of the sole carbon source by *Glutamicinus glutamate* M6 was as follows: glucose, sucrose+, fructose, lactose, arabinose, acetate, citrate, starch, and mannose were used to detect *Glutamicinus glutamate* M6, and the test results were all positive.

8. The application of the *Glutamicinus glutamate* M6 strain that degrades 4-methylphenol according to claim 4 in reducing or eliminating the off-flavor of fermented bamboo shoots, characterized in that: The strains obtained by picking were identified by physiological and biochemical experiments and 16S rDNA sequence sequencing comparison with reference to Bergey's Manual of Systematic Bacteriology to determine the genus of the obtained strains. Based on the 16S rDNA sequencing alignment results, the top 10 strain sequences with the highest similarity were selected and a phylogenetic tree was constructed using MEGA 11. The Neighbor-Joining algorithm and 1000 Bootstrap statistical tests were used to construct the tree to determine the taxonomic position of Bacillus glutamicum M6.

9. The application of the *Glutamicinus glutamate* M6 strain that degrades 4-methylphenol according to claim 4 in reducing or eliminating the off-flavor of fermented bamboo shoots, characterized in that: The preparation method of fermented bamboo shoots in step (S01) is as follows: fresh bamboo shoots are peeled, cut into pieces, placed in sterilized headspace bottles, and incubated in an incubator at 20-30℃ in the dark for 5-9 days; the amount of fresh bamboo shoots used is 100g-700g, and the headspace bottles are available in sizes of 150mL, 200mL, 250mL, 500mL, or 800mL; the pieces are cut into 0.5-2cm pieces. 3 piece.

10. The application of the *Glutamicinus glutamate* M6 strain that degrades 4-methylphenol according to claim 1 in reducing or eliminating the off-flavor of fermented bamboo shoots, characterized in that: The *Glutamicinus glutamate* M6 was co-cultured in liquid MM medium containing 4-methylphenol under different conditions to detect its degradation ability of 4-methylphenol; the different conditions were different temperatures, different pH values, different concentrations of 4-methylphenol, and different incubation times. The cells were co-cultured at 16℃, 20℃, 25℃, 30℃ and 37℃ respectively, and the growth and degradation ability of 250 mg / L 4-methylphenol were detected after 24 h. The cells were co-cultured at pH values ​​of 4, 5, 6, 7, 8, 9 and 10, temperatures of 30°C and rotation speeds of 220 rpm, respectively, and the growth and degradation capacity for 250 mg / L 4-methylphenol were assessed after 24 h. The cells were co-cultured at 30℃ and 220rpm, and the growth was detected after 24h, as well as the degradation capacity of 4-methylphenol at different concentrations of 200, 300, 400, 500 and 600 mg / L. The cells were co-cultured at 30℃ and 220rpm, and the growth and degradation capacity of 250mg / L 4-methylphenol were detected at 8h, 16h, 24h, 32h and 40h.

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