Corynebacterium glutamicum mutant strain with improved L-glutamic acid production capacity and method for producing L-glutamic acid using the same

Abstract

The present invention relates to a Corynebacterium glutamicum mutant strain with improved L-glutamic acid production ability, a method for producing the same, and a method for producing L-glutamic acid using the same. The Corynebacterium glutamicum mutant strain has a mechanosensitive ion channel gene derived from Corynebacterium sp. introduced therein, which enhances glutamic acid excretion and improves L-glutamic acid production yield. Therefore, by using the mutant strain, L-glutamic acid can be produced more efficiently.

Description

Technical Field

[0001] The present invention relates to a Corynebacterium glutamicum mutant strain with improved L-glutamic acid-producing ability and a method for producing L-glutamic acid using the same. Specifically, the present invention relates to a Corynebacterium glutamicum mutant strain in which a mechanosensitive ion channel gene derived from a Corynebacterium sp. strain is introduced to improve the L-glutamic acid-producing ability, a method for producing the same, and a method for producing L-glutamic acid using the same.

Background Art

[0002] L-Glutamic acid is a typical amino acid produced by microbial fermentation. Monosodium L-glutamate (MSG) enhances the preference for foods such as meat, fish, chicken, vegetables, sauces, soups, and seasonings by balancing the overall taste of food, and can enhance the taste of low-salt foods with up to 30% salt reduction. It is widely used as a seasoning for household and processed food production.

[0003] A brief look at the fermentation pathway of L-glutamic acid reveals that glucose primarily passes through the EMP pathway, but some is metabolized into two molecules of pyruvic acid via the hexose phosphate pathway (HMP). One of these molecules fixes CO2 to become oxaloacetic acid, while the other combines with acetyl-CoA to become citric acid. Furthermore, oxaloacetic acid and citric acid enter the citric acid cycle (TCA cycle) to become alpha-ketoglutaric acid. Here, the oxidative metabolic pathway that oxidizes alpha-ketoglutaric acid to succinic acid is absent, and because isocitrate dehydrogenase and glutamate dehydrogenase are closely involved, the reductive amino acid conversion reaction of alpha-ketoglutaric acid proceeds efficiently to produce L-glutamic acid.

[0004] L-glutamic acid is typically produced by fermentation using strains and mutants of the Brevibacterium and Corynebacterium genera. To increase L-glutamic acid production through microbial culture, methods have been used to regulate the expression of genes involved in L-glutamic acid biosynthesis. These methods mainly involve increasing the copy number of the gene or modifying the gene's promoter to regulate enzyme activity in the biosynthetic pathway. Specifically, L-glutamic acid production has been increased by amplifying specific genes such as the pyc gene and fasR (US Patent No. 6,852,516) or by manipulating the promoter sites of the gdh, gltA, icd, pdh, and argG genes (US Patent No. 6,962,805). Thus, most of the genes involved in the glutamate biosynthesis pathway are already known, and there is a need to discover new genes that can increase glutamate production and develop new glutamate-producing strains that reflect these genes.

[0005] Therefore, the inventors discovered a new gene that helps excrete L-glutamic acid, and by introducing this gene into an L-glutamic acid-producing bacterial strain to create a mutant strain, they confirmed that the L-glutamic acid production capacity of the mutant strain was improved, thus completing the present invention. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] U.S. Registered Patent No. 6,852,516 [Patent Document 2] U.S. Registered Patent No. 6,962,805 [Overview of the project] [Problems that the invention aims to solve]

[0007] The present invention aims to provide a Corynebacterium glutamicum mutant strain that contains a mechanosensitive ion channel gene derived from a Corynebacterium strain and exhibits improved L-glutamic acid production capacity.

[0008] Furthermore, the present invention aims to provide a method for producing the Corynebacterium glutamicum mutant strain, which includes the step of introducing a mechanosensitive ion channel gene derived from a Corynebacterium strain.

[0009] Furthermore, the present invention aims to provide a method for producing L-glutamic acid, comprising the steps of i) culturing the Corynebacterium glutamicum mutant strain in an L-glutamic acid production medium, and ii) recovering L-glutamic acid from the mutant strain or the culture medium in which the mutant strain was cultured. [Means for solving the problem]

[0010] One aspect of the present invention provides a Corynebacterium glutamicum mutant strain that contains a mechanosensitive ion channel gene derived from a Corynebacterium strain and has improved L-glutamic acid production capacity.

[0011] The inventors have strived to develop a novel Corynebacterium glutamicum mutant strain capable of improving L-glutamic acid production. As a result, they have confirmed that by introducing a mechanosensitive ion channel-related gene derived from a Corynebacterium species into a Corynebacterium glutamicum strain that produces L-glutamic acid, the excretion of L-glutamic acid is facilitated, and the L-glutamic acid productivity of the mutant strain is significantly improved.

[0012] In this invention, "Corynebacterium strain" refers to a strain derived from a mechanosensitive ion channel gene intended to be introduced into a Corynebacterium glutamicum strain, and can include all Corynebacterium microorganisms. Specifically, Corynebacterium glutamicum, Corynebacterium crudilactis, Corynebacterium deserti, Corynebacterium callunae, Corynebacterium suranareeae, Corynebacterium lubricantis, Corynebacterium doosanense, Corynebacterium efficiens, Corynebacterium uterequi, Corynebacterium stationis Corynebacterium stationis, Corynebacterium pacaense, Corynebacterium singulare, Corynebacterium humireducens, Corynebacterium marinum, Corynebacterium halotolerans, Corynebacterium spheniscorum, Corynebacterium freiburgense, Corynebacterium striatum, Corynebacterium canis, Corynebacterium ammoniagenes ammoniagenes), Corynebacterium renale (Coryneb. It may also be *Corynebacterium renale*, *Corynebacterium pollutisoli*, *Corynebacterium imitans*, *Corynebacterium caspium*, *Corynebacterium testudinoris*, *Corynebacterium pseudopelargi*, or *Corynebacterium flavescens*.

[0013] In the present invention, "mechanically sensitive ion channels" are channels present in the cell membranes of eukaryotes as well as bacteria, and are involved in osmotic homeostasis. The genes that encode such mechanically sensitive ion channels may be derived from strains of the genus Corynebacterium, and preferably from the nucleotide sequence of SEQ ID NO: 1 derived from Corynebacterium deserti, SEQ ID NO: 2 derived from Corynebacterium crudilactis, or SEQ ID NO: 3 derived from Corynebacterium callunae. In this case, the nucleotide sequences may include those with homology of 60% or more, preferably 70% or more, more preferably 80% or more, even more preferably 90% or more, and most preferably 95% or more, to the nucleotide sequences of SEQ ID NOs: 1 to 3. The aforementioned "homology of % or more" is confirmed by comparing two optimally sequenced sequences with a comparison region, where some of the polynucleotide sequences in the comparison region may contain additions or deletions (i.e., gaps) compared to the reference sequence (without additions or deletions) for the optimal sequences of the two sequences. Furthermore, genes encoding mechanosensitive ion channels may undergo mutations that occur naturally or unnaturally (e.g., genetic recombination, radioactivity, chemical treatment, etc.), and such mutations may weaken or strengthen the function of the gene.

[0014] According to one specific example of the present invention, the mechanosensitive ion channel gene may be encoded in any one of the base sequences of SEQ ID NOs: 1 to 5.

[0015] The base sequence of Sequence ID No. 1 may be that of a mechanosensitive ion channel gene derived from Corynebacterium deserti, the base sequence of Sequence ID No. 2 may be that of a mechanosensitive ion channel gene derived from Corynebacterium crudilactis, and the base sequences of Sequence IDs No. 3 to 5 may be that of a mechanosensitive ion channel gene derived from Corynebacterium carnae. Here, the base sequences of Sequence IDs No. 4 and 5 may encode the amino acid sequence of a mechanosensitive ion channel gene derived from Corynebacterium carnae in which the 107th amino acid is substituted from leucine (LEU) to alanine (ALA) or valine (VAL).

[0016] The inventors hypothesized that the mechanosensible ion channel gene involved in glutamate efflux in Corynebacterium glutamicum has a base sequence with more than 70% homology (Corynebacterium deserti 74%, Corynebacterium crudilactis 72%, Corynebacterium carnae 70%) and plays the same role in glutamate efflux. They confirmed that the glutamate productivity of the mutant strain containing the mechanosensible ion channel gene in the present invention was significantly improved compared to other glutamate-producing strains.

[0017] In the present invention, a strain with "improved productivity" means one in which the productivity of L-glutamic acid has increased compared to the parent strain. The parent strain refers to the wild type or mutant strain that is the target of mutation, and includes strains that are directly targeted for mutation or those that are transformed by recombinant vectors, etc. In the present invention, the parent strain may be a wild-type Corynebacterium glutamicum strain or a strain that has mutated from the wild type. Preferably, it may be the Corynebacterium glutamicum KCTC 11558BP strain.

[0018] A Corynebacterium glutamicum mutant strain with improved L-glutamic acid production ability according to one specific example of the present invention produces 5% or more, specifically 5-20%, more L-glutamic acid than the parent strain, and can produce 36-50g of L-glutamic acid per liter of culture medium, preferably 38-45g.

[0019] Another aspect of the present invention provides a method for producing the Corynebacterium glutamicum mutant strain, comprising the step of introducing a mechanosensitive ion channel gene derived from a Corynebacterium strain.

[0020] The aforementioned step involves transforming the parent strain with a vector containing polynucleotides that encode the mechanosensitive ion channel gene.

[0021] In the present invention, "vector" refers to any agent for cloning and / or transferring bases into a host cell. The vector may be a replicon to which other DNA fragments bind and which brings about the replication of the bound fragments. The "replicon" refers to any genetic unit (e.g., plasmid, phage, cosmid, chromosome, virus) that functions as a self-unit of DNA replication in vivo, i.e., can be replicated by its own regulation. In the present invention, the vector is not particularly limited as long as it can replicate in the host, and any vector known in the art can be used. The vector used for the production of the recombinant vector may be a plasmid, cosmid, virus, or bacteriophage in a natural state or a recombinant state. For example, as phage vectors or cosmid vectors, pWE15, M13, λEMBL3, λEMBL4, λFIXII, λDASHII, λZAPII, λgt10, λgt11, Charon4A, and Charon21A, etc. can be used, and as plasmid vectors, pDZ vectors, pBR series, pUC series, pBluescriptII series, pGEM series, pTZ series, pCL series, and pET series, etc. can be used. The usable vectors are not particularly limited, and known expression vectors can be used, but are not limited thereto.

[0022] In the present invention, "transformation" means introducing a gene into a host cell so as to be expressed in the host cell, and the transformed gene is included without limitation as long as it can be expressed in the host cell, whether it is inserted into the chromosome of the host cell or located extrachromosomally. In the present invention, as an example of the transformation method, an electroporation method (van der Rest et al., Appl. Microbiol. Biotechnol., 52, 541-545, 1999) etc. may be used.

[0023] Another aspect of the present invention provides a method for producing L-glutamic acid, comprising: i) culturing the Corynebacterium glutamicum mutant strain in an L-glutamic acid production medium; and ii) recovering L-glutamic acid from the mutant strain or the culture broth in which the mutant strain has been cultured.

[0024] The above-mentioned culturing is carried out using an appropriate medium and culturing conditions known in the art, and an ordinary technician can easily adjust and use the medium and culturing conditions. Specifically, the medium may be a liquid medium, but is not limited thereto. The culturing method can include, for example, batch culture, continuous culture, fed-batch culture, or a combined culture thereof, but is not limited thereto.

[0025] According to a specific example of the present invention, the medium must meet the requirements of a specific strain in an appropriate manner and can be appropriately modified by an ordinary technician. The culture medium for Corynebacterium strains can refer to known literature (Manual of Methods for General Bacteriology. American Society for Bacteriology. Washington D.C., USA, 1981), but is not limited thereto.

[0026] According to one specific example of the present invention, the culture medium may contain a variety of carbon sources, nitrogen sources, and trace element components. Usable carbon sources include sugars and carbohydrates such as glucose, sucrose, lactose, fructose, maltose, starch, and cellulose; oils and fats such as soybean oil, sunflower oil, castor oil, and coconut oil; fatty acids such as palmitic acid, stearic acid, and linoleic acid; alcohols such as glycerol and ethanol; and organic acids such as acetic acid. These substances may be used individually or in mixtures, but are not limited thereto. Usable nitrogen sources include peptone, yeast extract, meat juice, malt extract, corn maceration, soybean barley, and urea or inorganic compounds, such as ammonium sulfate, ammonium chloride, ammonium phosphate, ammonium carbonate, and ammonium nitrate. Nitrogen sources may also be used individually or in mixtures, but are not limited thereto. Usable phosphorus sources may include, but are not limited thereto, potassium dihydrogen phosphate or dipotassium hydrogen phosphate or corresponding sodium-containing salts. Furthermore, the culture medium may, but is not limited to, contain metal salts such as magnesium sulfate or iron sulfate necessary for growth. Other essential growth substances, such as amino acids and vitamins, may also be included. In addition, suitable precursors can be used in the culture medium. The medium or individual components may, but are not limited to, be added to the culture medium in batches or sequentially in a manner appropriate to the culture process.

[0027] According to one specific example of the present invention, the pH of the microbial culture medium can be adjusted by adding compounds such as ammonium hydroxide, potassium hydroxide, ammonia, phosphoric acid, and sulfuric acid to the culture medium in an appropriate manner during cultivation. Furthermore, the formation of bubbles can be suppressed during cultivation using an antifoaming agent such as fatty acid polyglycol ester. Additionally, oxygen or an oxygen-containing gas (e.g., air) can be injected into the culture medium to maintain an aerobic state. The temperature of the culture medium is typically 20°C to 45°C, for example, 25°C to 40°C. The cultivation period may continue until the useful substance is obtained in the desired yield, or it may be, for example, 10 to 160 hours.

[0028] According to one specific example of the present invention, the step of recovering L-glutamic acid from the cultured mutant strain and culture medium can be performed by collecting or recovering the L-glutamic acid produced from the medium using a suitable method known in the art, depending on the culture method. For example, methods such as centrifugation, filtration, extraction, spraying, drying, evaporation, precipitation, crystallization, electrophoresis, fractional dissolution (e.g., ammonium sulfate precipitation), and chromatography (e.g., ion exchange, affinity, hydrophobicity, and size exclusion) can be used, but are not limited to these.

[0029] According to one specific example of the present invention, the step of recovering glutamic acid can be performed by separating the supernatant obtained by removing biomass from the culture by slow centrifugation using ion exchange chromatography.

[0030] According to one specific example of the present invention, the step of recovering L-glutamic acid may include a step of purifying L-glutamic acid. [Effects of the Invention]

[0031] In one specific example of the present invention, a Corynebacterium glutamicum mutant strain is introduced, thereby enhancing glutamate efflux and improving the L-glutamate production yield. Therefore, using this mutant strain allows for more effective production of L-glutamate. [Brief explanation of the drawing]

[0032] [Figure 1] This figure shows the structure of the pKmscS1 vector containing a mechanosensitive ion channel gene derived from the Corynebacterium deserti strain. [Figure 2]This figure shows the structure of the pKmscS3-L107A vector, which contains a mechanosensitive ion channel gene derived from the Corynebacterium callunae strain in which the 107th amino acid residue is substituted from leucine (LEU) to alanine (ALA). [Modes for carrying out the invention]

[0033] The present invention will be described in more detail below. However, such description is provided only as an example to aid in understanding the present invention, and the scope of the present invention is not limited by such exemplary description. [Examples]

[0034] Example 1. Production of Corynebacterium glutamicum mutant strains 1-1. Production of a vector into which a mechanosensitive ion channel gene derived from Corynebacterium deserti (C. deserti) has been introduced. To introduce the mechanosensitive ion channel gene mscS1, chromosomal DNA was isolated and purified from Corynebacterium deserti (C. deserti GIMN1.010), and then used as a template for amplification by PCR (30 seconds at 95°C, 30 seconds at 58°C, 2 minutes at 72°C, 30 repeats) using primers 3 and 4 shown in Table 1 below.

[0035] The amplified genes were amplified by PCR (30 seconds at 95°C, 30 seconds at 58°C, and 2 minutes at 72°C, 30 repetitions) using primers 1 and 2 and 5 and 6 (Table 1) to recognize the position of the vector into which the amplified gene was to be inserted. The PCR products were examined by electrophoresis to identify bands of approximately 1,500 bp, 1,600 bp, and 1,500 bp, respectively.

[0036] Each purified PCR product (mscS1 gene and vector) was further used as a template for a crossover polymerase chain reaction (PCR), and amplified again using the crossover PCR method (Bacteriol., 179:6228-6237, 1997) with primers 1 and 6 shown in Table 1 below. Subsequently, the 4.6kb PCR product was purified, digested with BamHI restriction enzyme (Takara, Japan), and cloned into a pK19mobSacB vector (Gene, 145:69-73, 1994) digested with the same restriction enzyme to produce the pKmscS1 vector for mscS1 gene introduction (Figure 1).

[0037] [Table 1]

[0038] 1-2. Production of a vector into which a mechanosensitive ion channel gene derived from Corynebacterium crudilactis has been introduced. The pKmscS2 vector for mscS2 gene transfer was prepared in the same manner, except that Corynebacterium crudilactis strain JZ16 was used instead of Corynebacterium deserti as described in 1-1, and the primers shown in Table 2 below were used.

[0039] [Table 2]

[0040] 1-3. Production of a vector into which a mechanosensitive ion channel gene derived from Corynebacterium carnae has been introduced. The pKmscS3 vector for mscS3 gene transfer was prepared in the same manner, except that Corynebacterium callunae (C. callunae DSM 20147) was used instead of Corynebacterium deserti as described in 1-1 above, and the primers shown in Table 3 below were used.

[0041] [Table 3]

[0042] 1-4. Production of vectors into which amino acid residue mutations have been introduced into the mechanosensitive ion channel gene derived from Corynebacterium carnae (C. callunae). To introduce the mechanosensitive ion channel gene mscS3 by substituting the 107th amino acid residue, chromosomal DNA was isolated and purified from Corynebacterium carnae (C. callunae DSM 20147). This was then used as a template and amplified by PCR (30 seconds at 95°C, 30 seconds at 58°C, 2 minutes at 72°C, 30 repetitions) using primers 1 and 2 and 3 and 4 shown in Table 4 below.

[0043] Each purified PCR product (mscS3 gene and vector) was further used as a template for a crossover polymerase chain reaction (PCR), and amplified again using the crossover PCR method (Bacteriol., 179:6228-6237, 1997) with primers 1 and 4 shown in Table 4 below. Subsequently, the 718 bp PCR product was purified, cleaved with BamHI restriction enzyme (Takara, Japan), and cloned into a pK19mobSacB vector (Gene, 145:69-73, 1994) cleaved with the same restriction enzyme to produce a mutagenetic pKmscS3-L107A vector in which the 107th leucine residue of the mscS3 gene was replaced with alanine (Figure 2).

[0044] [Table 4]

[0045] 1-5. Production of vectors into which amino acid residue mutations have been introduced into the mechanosensitive ion channel gene derived from Corynebacterium carnae (C. callunae). The pKmscS3-L107V vector for mutagenesis, which replaces the 107th leucine residue of the mscS3 gene with valine, was manufactured in the same manner, except that the primers shown in Table 5 below were used instead of the primers described in 1-4 above.

[0046] [Table 5]

[0047] 1-6. Transformation and production of mutant strains of Corynebacterium glutamicum KCTC 11558BP strain For the transformation of the Corynebacterium glutamicum KCTC 11558BP strain, a method for producing modified electrocompetent cells based on the van der Rest et al. method was used.

[0048] First, Corynebacterium glutamicum KCTC 11558BP strain was primarily cultured in 100 ml of 2YT medium (16 g / l tryptone, 10 g / l yeast extract, 5 g / l sodium chloride) supplemented with 2% glucose. Then, to the same medium with the glucose removed, isonicotinic acid hydrazine at a concentration of 1 mg / ml and 2.5% glycine were added. Subsequently, OD (Oral Dissociation) was performed. 610 After inoculating the seed culture solution to achieve a value of 0.3, incubate at 18°C ​​and 180 rpm for 12-16 hours to obtain an OD (Oxygen Demand). 610The values ​​were adjusted to 1.2-1.4. After standing on ice for 30 minutes, the cells were centrifuged at 4°C and 4000 rpm for 15 minutes. The supernatant was then discarded, and the precipitated Corynebacterium glutamicum KCTC 11558BP strain was washed four times with 10% glycerol solution. Finally, competent cells were prepared by resuspending the cells in 0.5 ml of 10% glycerol solution. Electroporation was performed using an electroporator from Bio-Rad. The prepared competent cells and the respective manufactured pKmscS1, pKmscS2, pKmscS3, pKmscS3-L107A, and pKmscS3-L107V vectors were added to an electroporation cuvette (0.2 mm), and then an electric shock was applied under conditions of 2.5 kV, 200 Ω, and 12.5 μF. Immediately after the electric shock was completed, 1 ml of regeneration medium (containing Brain Heart infusion 18.5 g / l and sorbitol 0.5 M) was added and heat-treated at 46°C for 6 minutes. After cooling to room temperature, the mixture was transferred to a 15 ml capped tube and incubated at 30°C for 2 hours. The mixture was then streaked onto selection medium (containing tryptone 5 g / l, NaCl 5 g / l, yeast extract 2.5 g / l, Brain Heart infusion powder 18.5 g / l, agar 15 g / l, sorbitol 91 g / l, and kanamycin 20 μg / l). Colonies were incubated at 30°C for 72 hours to induce secondary recombination in BHI medium until the quiescent phase. -5 ~10 -7 Dilute to the specified concentration and spread onto antibiotic-free plates (containing 10% sucrose) in a culture medium that is free from kanamycin resistance and contains 10% sucrose. Growing strains were selected from the samples. The obtained colonies were identified as Corynebacterium glutamicum mutants (IS1, IS2, IS3) with the mscS1, mscS2, and mscS3 genes introduced, respectively, using primers 7 and 8 from Tables 1-3. Corynebacterium glutamicum mutants (IS3-A, IS3-V) with the mscS3-L107A and mscS3-L107V genes introduced, respectively, using primers 5 and 6 from Tables 4 and 5.

[0049] Experimental Example 1. Comparison of L-glutamic acid productivity of mutant strains. The L-glutamic acid productivity of the mscS1, mscS2, and mscS3 gene-transfected mutant strains (IS1, IS2, IS3) produced in Example 1 was compared with that of the parent strain, Corynebacterium glutamicum KCTC 11558BP.

[0050] The mutant strain and parent strain were each streaked onto activated plate medium (pH 7.5) having the composition shown in Table 6 below, and incubated at 30°C for 24 hours. Subsequently, 10 mL of flask medium (pH 7.6) having the composition shown in Table 7 below was placed in a 100 mL flask, and one loop of each strain cultured on plate medium was inoculated into it. Incubation was then carried out at 30°C and 200 rpm for 48 hours. After incubation was complete, the amount of L-glutamic acid in the culture medium was measured, and the results are shown in Table 8 below.

[0051] [Table 6]

[0052] [Table 7]

[0053] [Table 8]

[0054] As shown in Table 8 above, the Corynebacterium glutamicum mutants IS1, IS2, and IS3 were found to have increased L-glutamic acid production by approximately 8%, 7%, and 9%, respectively, compared to the parent strain Corynebacterium glutamicum KCTC 11558BP, which did not have the mscS1 gene from Corynebacterium deserti, the mscS2 gene from Corynebacterium crudilactis, or the mscS3 gene from Corynebacterium callunae introduced into them.

[0055] Experimental Example 2. Comparison of L-glutamic acid productivity of mutant strains with and without amino acid residue substitutions. The L-glutamic acid productivity of the mscS3, mscS3-L107A, and mscS3-L107V gene-transfected mutants (IS3, IS3-A, IS3-V) produced in Example 1 was compared with that of the parent strain, Corynebacterium glutamicum KCTC 11558BP.

[0056] The bacterial strain was cultured using the same method as in Experimental Example 1, and the amount of L-glutamic acid was measured. The results are shown in Table 9 below.

[0057] [Table 9]

[0058] As shown in Table 9 above, the Corynebacterium glutamicum mutants IS3, IS3-A, and IS3-V were confirmed to have increased L-glutamic acid production by approximately 9%, 12%, and 4%, respectively, compared to the parent strain Corynebacterium glutamicum KCTC 11558BP.

[0059] In particular, when the 107th amino acid residue was substituted from leucine to alanine (IS3-A), L-glutamate production increased compared to when the amino acid residue was not substituted (IS3) or when it was substituted from leucine to valine (IS3-V). This indicates that the 107th amino acid residue in the mscS3 gene derived from Corynebacterium carnae is an important position involved in glutamate production. The present invention has been described so far, focusing on preferred embodiments. Those with ordinary skill in the art to which the present invention pertains will understand that the present invention can be realized in modified forms that do not depart from the essential characteristics of the invention. Therefore, the disclosed embodiments should be considered in an explanatory rather than restrictive manner. The scope of the invention is shown in the claims, not in the above description, and all differences within an equivalent scope should be construed as being included in the invention.

Claims

1. A mutant strain of Corynebacterium glutamicum with improved L-glutamic acid production capacity, The Corynebacterium glutamicum mutant strain contains a mechanosensitive ion channel gene derived from one strain selected from the group consisting of Corynebacterium deserti, Corynebacterium crudilactis, and Corynebacterium callunae. Corynebacterium glutamicum mutant strain, wherein the mechanosensitive ion channel gene is encoded by the nucleotide sequence of SEQ ID NO: 1, 2, 3, 4, or 5.

2. A method for producing a Corynebacterium glutamicum mutant according to claim 1, comprising the step of introducing a mechanosensitive ion channel gene derived from one strain selected from the group consisting of Corynebacterium deserti, Corynebacterium crudilactis, and Corynebacterium callunae, A method for producing the machine-sensitive ion channel gene, wherein the machine-sensitive ion channel gene is encoded by the base sequence of SEQ ID NO: 1, 2, 3, 4, or 5.

3. i) The step of culturing the Corynebacterium glutamicum mutant strain described in claim 1 in L-glutamic acid production medium, ii) A step of recovering L-glutamic acid from the mutant strain or the culture medium in which the mutant strain was cultured. A method for producing L-glutamic acid containing [a specific ingredient].

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