CN117486982A - Use of the transport protein TdcC for increasing the yield of L-carnosine - Google Patents

Abstract

The invention belongs to the technical field of biology, and particularly provides an application of a transport protein TdcC or a coding gene thereof in improving the yield of L-carnosine, wherein the amino acid sequence of the transport protein TdcC is shown as SEQ ID NO. 1. The transport protein TdcC can obviously improve the yield of the recombinant strain L-carnosine, has stable yield and has wide application prospect in industrial production of the L-carnosine.

Description

Use of the transport protein TdcC for increasing the yield of L-carnosine

Technical Field

The invention belongs to the technical field of biology, and particularly relates to an application of a transport protein TdcC in improving the yield of carnosine.

Background

L-carnosine (beta-alanyl-L-histidine) and its analogues (e.g., homocarnosine and anserine) are naturally active dipeptides that are widely found in the brain, muscle and other important tissues of mammals. Since the active peptide has been found for over one hundred years, a great deal of researches have found or proved that the L-carnosine has remarkable activities of resisting oxidation, eliminating intracellular free radicals, resisting aging and the like, and is clinically used for auxiliary treatment on hypertension, heart diseases, senile cataract, ulcers, anti-tumor, wound healing and the like, and the active peptide and derivatives thereof have wide application in the fields of medicine, health care, sanitation, cosmetics and the like due to the strong antioxidant activity, low toxic and side effects and multiple physiological activities.

The L-carnosine synthesis processes reported so far are mainly divided into two categories: one type is chemical synthesis, and the other type is biocatalytic synthesis.

Although there are many chemical synthesis methods, there are mainly two kinds of methods: firstly, beta-alanine is utilized to participate in synthesis. The main route is that beta-alanine is condensed with protected L-histidine after amino protection and carboxyl activation, and then protective groups are removed to obtain the L-carnosine. The route is complex, the yield is low, racemization is easy to occur in the process of forming peptide bonds, the purity of the product is influenced, the solvent consumption is high, and environmental pollution is easy to cause; and secondly, the reaction involved in the beta-alanine is abandoned. The main principle is that L-histidine forms peptide bond with different beta-alanine precursor before further conversion into carnosine. The route is relatively simple, the processes of protecting and deprotecting different groups are omitted, racemization reaction is avoided, anhydrous operation is required, and the requirements are strict. The above route is along with the difference of the process, and the product yield is about 60% -80%.

In order to avoid the disadvantages of the chemical synthesis method, such as the addition and removal of the protecting groups required under the synthesis conditions, severe reaction temperature change, frequent pH adjustment, high reaction pressure, complex multiphase reaction system, inflammable, explosive and toxic solvent, complex intermediate product separation process and the like.

In recent years, researchers at home and abroad have been working on the production of L-carnosine by a biological method, i.e., the synthesis of L-carnosine by an enzyme or strain under mild conditions. There are two main routes:

(1) Beta aminopeptidase-based L-carnosine synthesis: beta-aminopeptidases are a class of functionally and structurally similar enzymes that have the activity to catalyze hydrolysis or ammonolysis of amide bonds or peptide bonds containing beta-amino acid residues. The mechanism is that the substrate and enzyme form an acylated intermediate, and then nucleophilic action is carried out with water or another amino acid, so as to complete hydrolysis or ammonolysis reaction. The enzyme has the potential of synthesizing beta peptide because of the special catalytic activity of the enzyme to the substrate containing the beta-amino acid, and the yield of the L-carnosine reaches 71 percent after the method is optimized, and the production strength is 3.3mM/L/h. The full strain is repeatedly utilized for 5 times, so that the synthesis efficiency of the L-carnosine is not changed significantly.

(2) L-carnosine Synthesis by L-carnosine enzymes: l-carnosine enzymes are dipeptidases that are present both inside and outside the strain. Wherein human serum carnosine enzyme (CN 1) catalyzes the hydrolysis of Xaa-His dipeptide to maintain carnosine balance in the serum. Chiaki Inaba et al constructed a catalytic system for L-carnosine synthesis in a whole strain one-step method based on Saccharomyces cerevisiae strain surface display technology by using human carnosine enzyme CN1 to connect with the strain wall adhesion domain of alpha-lectin. Compared with an escherichia coli catalytic system developed by Heyland Jan et al, the strain can directly catalyze cheap beta-alanine and L-histidine to synthesize L-carnosine. However, since the synthesis of L-carnosine is a reverse reaction of the hydrolysis of dipeptides catalyzed by L-carnosine enzymes, the synthesis process needs to be performed in an organic solvent or a hydrophobic ionic liquid in order to avoid the influence of water molecules. Nevertheless, the strain exhibits only 5% of L-carnosine synthesis efficiency, which is a great distance from commercial applications.

Chinese patent application 202211727024.8 discloses a kind of pallor bacillus with preservation number of CGMCC No.25590 and its application in synthesizing L-carnosine. The strain can directly utilize L-histidine and beta-alanine to synthesize carnosine, and the yield of the L-carnosine can be up to about 20mg/L.

Chinese patent application 202211706675.9 discloses a protease with a carnosine hydrolase function and application thereof in L-carnosine synthesis, the application adopts a biological enzyme method to catalyze and synthesize L-carnosine, the content of L-carnosine in a conversion solution is 100-125g/L, and the conversion rate is more than 65% based on L-histidine, so that the protease has the advantages of high conversion rate, good repeatability and short conversion time.

There is a need in the art for more biological methods of preparation that increase the yield of L-carnosine.

Disclosure of Invention

In order to achieve the technical purpose of improving the yield of the L-carnosine, the invention provides the following technical scheme:

in one aspect, the invention provides an application of a transport protein TdcC or a coding gene thereof in improving the yield of L-carnosine, wherein the amino acid sequence of the transport protein TdcC is shown as SEQ ID NO. 1.

In some embodiments, the transporter TdcC is used to facilitate extracellular transport of L-carnosine.

In some embodiments, the nucleotide sequence of the coding gene is shown in SEQ ID NO. 2.

In some embodiments, the coding gene is comprised in a recombinant plasmid, preferably a recombinant plasmid that overexpresses the transporter TdcC.

In some preferred embodiments, the recombinant plasmid is pEZ07-tdcC.

In some embodiments, the recombinant plasmid is comprised in a genetically engineered strain.

In some embodiments, the genetically engineered strain is Escherichia coli (Escherichia coli), preferably Escherichia coli CGMCC No.27382.

In another aspect, the invention provides the use of the transporter TdcC or a gene encoding the same in the production of L-carnosine, wherein the amino acid sequence of the transporter TdcC is shown as SEQ ID NO. 1.

In some embodiments, the nucleotide sequence of the coding gene is shown in SEQ ID NO. 2.

In some embodiments, the coding gene is contained in the genetically engineered strain, or integrated in the genome of the genetically engineered strain.

In some embodiments, the genetically engineered strain is escherichia coli, preferably CGMCC No.27382 escherichia coli.

In yet another aspect, the present invention provides a method for producing L-carnosine, comprising:

(1) Introducing a recombinant plasmid comprising a TdcC encoding gene into a host strain; or (b)

(2) Integrating the TdcC encoding gene into the genome of the host strain; or (b)

(3) Culturing a genetically engineered strain with an L-carnosine expression function.

In some embodiments, the genetically engineered strain is CGMCC No.27382 escherichia coli.

In some embodiments, the nucleotide sequence of the TdcC encoding gene is set forth in SEQ ID NO. 2.

SEQ ID NO:1：

MSTSDSIVSSQTKQSSWRKSDTTWTLGLFGTAIGAGVLFFPIRAGFGGLIPILLMLVLAYPIAFYCHRALARLCLSGSNPSGNITETVEEHFGKTGGVVITFLYFFAICPLLWIYGVTITNTFMTFWENQLGFAPLNRGFVALFLLLLMAFVIWFGKDLMVKVMSYLVWPFIASLVLISLSLIPYWNSAVIDQVDLGSLSLTGHDGILITVWLGISIMVFSFNFSPIVSSFVVSKREEYEKDFGRDFTERKCSQIISRASMLMVAVVMFFAFSCLFTLSPANMAEAKAQNIPVLSYLANHFASMTGTKTTFAITLEYAASIIALVAIFKSFFGHYLGTLEGLNGLVLKFGYKGDKTKVSLGKLNTISMIFIMGSTWVVAYANPNILDLIEAMGAPIIASLLCLLPMYAIRKAPSLAKYRGRLDNVFVTVIGLLTILNIVYKLF

SEQ ID NO:2：

ATGagtacttcagatagcattgtatccagccagacaaaacaatcgtcctggcgtaaatcagataccacatggacgttaggcttgtttggtacggcaatcggcgccggggtgctgttcttccctatccgcgcaggttttggcggactgatcccgattcttctgatgttggtattggcataccccatcgcgttttattgccaccgggcgctggcgcgtctgtgtctttctggctctaacccttccggcaacattacggaaacggtggaagagcattttggtaaaactggcggcgtggttatcacgttcctgtacttcttcgcgatttgcccactgctgtggatttatggcgttactattaccaatacctttatgacgttctgggaaaaccagctcggctttgcaccgctgaatcgcggctttgtggcgctgttcctgttgctgctgatggctttcgtcatctggtttggtaaggatctgatggttaaagtgatgagctacctggtatggccgtttatcgccagcctggtgctgatttctttgtcgctgatcccttactggaactctgcagttatcgaccaggttgacctcggttcgctgtcgttaaccggtcatgacggtatcctgatcactgtctggctggggatttccatcatggttttctcctttaacttctcgccaatcgtctcttccttcgtggtttctaagcgtgaagagtatgagaaagacttcggtcgcgacttcaccgaacgtaaatgttcccaaatcatttctcgtgccagcatgctgatggttgcagtggtgatgttctttgcctttagctgcctgtttactctgtctccggccaacatggcggaagccaaagcgcagaatattccagt gctttcttatctggctaaccactttgcgtccatgaccggtaccaaaacaacgttcgcgattacactggaatatgcggcttccatcatcgcactcgtggctatcttcaaatctttcttcggtcactatctgggaacgctggaaggtctgaatggcctggtcctgaagtttggttataaaggcgacaaaactaaagtgtcgctgggtaaactgaacactatcagcatgatcttcatcatgggctccacctgggttgttgcctacgccaacccgaacatccttgacctgattgaagccatgggcgcaccgattatcgcatccctgctgtgcctgttgccgatgtatgccatccgtaaagcgccgtctctggcgaaataccgtggtcgtctggataacgtgtttgttaccgtgattggtctgctgaccatcctgaACATCGTATACAAACTGTTTTAA

In yet another aspect, the present invention provides a method of increasing L-carnosine production by a host strain, the method comprising:

increasing the expression level of the transporter TdcC in said host strain; or (b)

(ii) introducing a recombinant plasmid encoding the transporter TdcC into said host strain.

In some embodiments, the host strain includes eukaryotic strains and prokaryotic strains.

In some embodiments, the prokaryotic strains include, but are not limited to, E.coli, B.subtilis.

In some embodiments, the host strain is escherichia coli (i.e., escherichia coli), preferably escherichia coli W3110.

In some preferred embodiments, the E.coli W3110 is a genetically engineered E.coli W3110, the E.coli W3110 knocks out the degradation, uptake gene of L-carnosine, and the feedback inhibition-deleted L-carnosine synthesis operon is integrated.

In some preferred embodiments, the escherichia coli W3110 is CGMCC No.27382 escherichia coli.

In some embodiments, the transporter TdcC has an amino acid sequence as set forth in SEQ ID NO. 1.

In some embodiments, the transporter TdcC has at least 1 amino acid difference, e.g., 1, 2, 3, 4, 5, or 6, compared to the amino acid sequence set forth in SEQ ID NO. 1.

In some embodiments, the transporter TdcC has an amino acid sequence with at least about 80%, 85%, 90%, 95%, 96%, 97%, 98% or 99% sequence identity to SEQ ID NO. 1.

In still another aspect, the present invention provides a genetically engineered strain deposited in the general microbiological center of the China Committee for culture Collection of microorganisms at 5 months and 18 days of 2023, with a deposit number of CGMCC No.27382, classified as Escherichia coli (Escherichia coli) at the accession number of Hospital No. 1, no. 3, north Chen West Lu, korea, beijing.

In view of the various researches on the improvement of amino acid yield by using transport proteins, 196 transport proteins from escherichia coli are over-expressed, and multiple shaking flask fermentation screening comparison verifies that the transport protein TdcC is finally screened out and applied to the improvement of the L-carnosine yield of host strains. The host strain has stable L-carnosine yield, the L-carnosine yield in the primary screening and the secondary screening is more than 1.7g/L, and the L-carnosine yield is obviously improved by about 28.9 percent compared with the control group.

Preservation information:

biological material: SHK20C/pHD641;

classification naming: escherichia coli;

preservation number: CGMCC No.27382;

preservation unit: china general microbiological culture Collection center (China Committee for culture Collection);

preservation time: 2023, 5, 18;

preservation address: no. 1 and No. 3 of the north cinquefoil of the morning sun area of beijing city.

Drawings

FIG. 1 shows the results of an experiment for determining L-carnosine in a fermentation broth by HPLC.

FIG. 2 shows the re-screening results of the transporter expression library.

Detailed Description

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly used in the art to which this invention belongs. For the purposes of explaining the present specification, the following definitions will apply, and terms used in the singular will also include the plural and vice versa, as appropriate.

The terms "a" and "an" as used herein include plural referents unless the context clearly dictates otherwise. For example, reference to "a strain" includes a plurality of such strains, equivalents thereof known to those skilled in the art, and so forth.

As used herein, the terms "comprising" or "comprises" are intended to mean that the compositions and methods include the recited elements but do not exclude other elements, but also include the case of "consisting of … …" as the context dictates otherwise.

The present invention will be described in further detail with reference to the following examples in order to make the objects, technical solutions and advantages of the present invention more apparent. The specific conditions are not noted in the examples and are carried out according to conventional conditions or conditions recommended by the manufacturer. All reagents or equipment were commercially available as conventional products without the manufacturer's attention. Numerous specific details are set forth in the following description in order to provide a better understanding of the invention. The specific embodiments described herein are for purposes of illustration only and are not to be construed as limiting the invention in any way. In addition, in the following description, descriptions of well-known structures and techniques are omitted so as not to unnecessarily obscure the present invention. Such structures and techniques are also described in a number of publications.

The invention relates to reagents and instruments:

LB medium: each liter of the culture medium contains 5g of yeast powder, 10g of sodium chloride, 10g of peptone and deionized water to a volume of 1L (J.Sam Brookfield Huang Peitang translation, molecular cloning guide 2002,1595). And (3) performing high-pressure steam sterilization on the solution for 20-30min at the sterilization temperature of 121 ℃ to obtain the LB culture medium used in the invention.

Fermentation medium (per liter): 30g of glucose, 200mL of 5N-5 times salt solution, 1mL of TM3 solution, 10mg of ferric citrate, 246mg of magnesium sulfate heptahydrate, 111mg of calcium chloride and 1 mug of thiamine are subjected to volume fixation to 1L by sterile deionized water. Sterilizing the above solution with high pressure steam at 121deg.C for 20-30min. Simultaneously preparing empty shake flasks, weighing 0.4g of calcium carbonate in each flask, and enabling the final concentration of the calcium carbonate to be 20g/L, thus obtaining the fermentation medium used by the invention.

Wherein the 5N-5 times of salt solution is 75.6g of disodium hydrogen phosphate dodecahydrate, 15g of potassium dihydrogen phosphate, 2.5g of sodium chloride and 25g of ammonium chloride, and the volume is fixed to 1L by ionized water; the TM3 solution was zinc chloride tetrahydrate 2.0g, calcium chloride hexahydrate 2.0g, sodium molybdate dihydrate 2.0g, copper sulfate pentahydrate 1.9g, boric acid 0.5g, hydrochloric acid 100mL, deionized water to a volume of 1L.

Instrument: constant temperature shaking incubator.

Example 1 shake flask fermentation method for verifying production of L-carnosine by recombinant strain

And (3) shaking and fermenting:

(1) Inoculating the recombinant strain into 3mL of LB culture medium containing antibiotics, and culturing at 37 ℃ with a shaking table at 250 rpm;

(2) Transferring 200 mu L of the seeds after 16h of culture to 2mL of LB liquid medium containing antibiotics, and culturing for 4h at a shaking table of 250rpm at 37 ℃;

(3) Transferring 2mL of the secondary seeds into a shake flask filled with 18mL of fermentation medium, placing the shake flask in a shaking table at 37 ℃ and culturing at 250rpm for 4 hours; (4) IPTG was added to a final concentration of 1mM, the temperature of the shaking table was adjusted to 34℃and the culture was continued for about 20 hours, and after 0.5mL of the fermentation broth and 0.5mL of water were mixed and centrifuged (12000 rpm,1 min), the supernatant was collected and subjected to HPLC detection.

EXAMPLE 2HPLC determination of L-carnosine in fermentation broth

The fermentation broth was diluted 2-fold with sterile water, centrifuged through a 0.22 μm filter and detected by High Performance Liquid Chromatography (HPLC). The HPLC parameters were as follows: ultimate AQ-C18, 4.6X10X105 μm was used; the mobile phase is A: acetonitrile, B:10mM sodium octane sulfonate +50mM potassium dihydrogen phosphate solution pH 3.0, a: b=15:85; the flow rate of the column is 1mL/min, and the temperature of the column is 30 ℃; the wavelength is 210nm, and the sample injection amount is 5 mu L (after dilution by 2 times); the detection time was 13min. Detecting the wavelength of 210nm by using an ultraviolet detector; the flow rate of the initial mobile phase is 1.0mL/min, the loading amount of the fermentation liquid is 5 mu L, and the column temperature is 30 ℃. The results showed that the peak time of L-carnosine was 10 minutes (FIG. 1).

Example 3 construction of a Transporter expression library

The inventors screened 196 transporters by search query and alignment, designed primers respectively, and constructed on low copy vectors pEZ07 (vector pEZ07 and Chinese patent application No. 201510093004.3) by seamless cloning to obtain 196 transporter expression plasmids pTR01-pTR196, taking pTR154 (i.e. pEZ 07-tdcC) as an example:

1) Using the Escherichia coli W3110 genome as a template, amplifying tdcC gene fragment by using a primer pair pTR154-F/pTR154-R respectively (the primer pair is shown in Table 1), obtaining fragments with the size of 1377bp and without impurity bands in electrophoresis;

2) Directly carrying out column recovery and purification (JieRut gum recovery and purification kit, shanghai JieRut bioengineering technology Co., ltd., product No. GK 2043) on the obtained fragment, and carrying out EZ cloning construction (GBclonart seamless cloning kit, suzhou Shenzhou gene Co., product No. GB 2001-48) on the obtained fragment by carrying out nanomolar ratio of 1:2 with pEZ vector fragment recovered by NcoI/XhoI digestion;

3) The recombined clone reaction liquid is subjected to warm bath for 30min in a water bath kettle at 45 ℃, then transferred to ice and placed for 5min, TG1 conversion competent strains are added, the mixture is uniformly placed for 5min, heat shock is carried out at 42 ℃ for 2min, 800 mu L of resuscitation culture medium LB is added after 2min of ice bath, centrifugation (8000 rpm,1min of centrifugation) is carried out after 1h of resuscitation culture, and LB plates containing 100mg/L spectinomycin are coated;

4) The next day the clone was picked and cultured overnight, the plasmid was extracted and subjected to cleavage verification, and finally the plasmid pEZ-tdcC, numbered pTR154 was constructed. Wherein the tdcC gene sequence of the transport protein is SEQ ID NO.2, the amino acid sequence of the encoded L-carnosine transport protein is SEQ ID NO. 1, and then host escherichia coli W3110 is transformed for shake flask fermentation.

The invention takes Escherichia coli W3110 (ATCC 27325) (genotype: F-mcrAmcrB IN (rrnD-rrnE) 1 lambda-) as a base strain, knocks out the degradation gene and uptake gene of L-carnosine, integrates an L-carnosine synthesis operon for relieving feedback inhibition, improves the feedback inhibition and weakening regulation thereof, and the like, thus obtaining an L-carnosine genetic engineering strain SHK20C/pHD641, which is classified and named as Escherichia coli (preservation number is CGMCC No. 27382).

The transfer protein library related plasmid obtained by the construction is transformed into a host SHK20C/pHD641 to respectively obtain recombinant strains containing different transfer proteins, and the strains and a control strain SHK20C/pHD641 and pEZ07 are subjected to shake flask primary screening and secondary screening to screen transfer proteins which are beneficial to improving the yield of L-carnosine.

TABLE 1 primers according to this example

Example 4 Primary screening of Transporter expression libraries

The method of shake flask fermentation in this example is the same as in example 1.

The mode of shake flask fermentation comparison in this example performs a preliminary screening of the transporter:

inoculating and cloning recombinant strains containing different transport proteins and control bacteria SHK20C/pHD641 and pEZ07 into LB test tubes containing 100mg/L spectinomycin respectively, and culturing overnight;

transferring 200 mu L of the seed cultured overnight to 2mL of LB liquid medium containing antibiotics, culturing for 4 hours at a shaking table of 250rpm at 37 ℃, transferring all the seeds into a shaking bottle filled with 18mL of fermentation medium, culturing for 4 hours at 250rpm in the shaking table of 37 ℃, adding IPTG to induce the culture at 34 ℃ overnight, and continuing culturing for about 20 hours;

0.5mL of the fermentation broth was diluted 2-fold with 0.5mL of ionized water, and the supernatant was centrifuged at 12000rpm for 1min and subjected to HPLC detection in the same manner as in example 2.

3 clones were picked for each strain for parallel fermentation and the results averaged. The primary screening result shows that the yield of L-carnosine is obviously reduced after the transporter of 60% (118/19) is over-expressed; the yield of L-carnosine increased by 20% -60% after only 3.5% (7/196) of transporter was overexpressed, and the initial screening results are shown in tables 2-14.

Table 2 preliminary screening of test results for group 1

Table 3 Experimental results of the preliminary screening of group 2

Table 4 Experimental results of the preliminary screening of group 3

Table 5 experimental results of the preliminary screening of group 4

Table 6 Experimental results of the preliminary screening of group 5

Table 7 Experimental results of the preliminary screening of group 6

Table 8 Experimental results of the preliminary screening of 7 groups

Table 9 results of the preliminary screening of group 8

Table 10 results of the preliminary screening of group 9

Table 11 Experimental results of the preliminary screening of group 10

Table 12 results of preliminary screening 11 groups

Table 13 results of the experiment of the preliminary screening 12 groups

Table 14 experimental results of the preliminary screening 13 groups

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Example 5 rescreening of a Transporter expression library

The 7 recombinant strains with significantly improved yield of primary screened L-carnosine were rescreened according to the shake flask fermentation method of example 1. After 2 rounds of shaking and re-screening fermentation, the yield of L-Car was examined.

The yield of L-Car was tdcC, kgtP, yegT, which was higher than 2g/L in the 7 recombinant strains initially screened, whereas the yield of kgtP was only 1.39g/L during the rescreening, the yield of yegT was only 1.48g/L, and the yield of tdcC was kept at 1.74g/L, so that the yield of L-carnosine was more stable in shake flask fermentation of the tdcC transporter overexpressing strain. The yield of L-carnosine was significantly increased by about 28.9% compared to the control, relative to the yield of 1.35g/L in the control (FIG. 2).

Finally, it should be noted that the above description is only for illustrating the technical solution of the present invention, and not for limiting the scope of the present invention, and that the simple modification and equivalent substitution of the technical solution of the present invention can be made by those skilled in the art without departing from the spirit and scope of the technical solution of the present invention.

Claims (10)

1. The application of the transport protein TdcC or the coding gene thereof in improving the yield of L-carnosine is characterized in that the amino acid sequence of the transport protein TdcC is shown as SEQ ID NO. 1.

2. The use according to claim 1, wherein the transporter TdcC is used to promote extracellular transport of L-carnosine.

3. The use according to claim 1 or 2, wherein the nucleotide sequence of the coding gene is shown in SEQ ID No. 2.

4. The use according to claim 3, wherein the coding gene is comprised in a recombinant plasmid.

5. The use according to claim 4, wherein the recombinant plasmid is comprised in a genetically engineered strain;

the genetic engineering strain is CGMCC No.27382 Escherichia coli.

6. The application of the transport protein TdcC or the coding gene thereof in the production of L-carnosine is characterized in that the amino acid sequence of the transport protein TdcC is shown as SEQ ID NO. 1.

7. The use according to claim 6, wherein the nucleotide sequence of the coding gene is shown in SEQ ID NO. 2.

8. The use according to claim 7, wherein the coding gene is comprised in a genetically engineered strain or integrated in the genome of a genetically engineered strain;

the genetic engineering strain is CGMCC No.27382 Escherichia coli.

9. A method of producing L-carnosine, said method comprising:

(1) Introducing a recombinant plasmid comprising a TdcC encoding gene into a host strain; or (b)

(2) Integrating the TdcC encoding gene into the genome of the host strain; or (b)

(3) Culturing a genetic engineering strain with an L-carnosine expression function;

the genetic engineering strain is CGMCC No.27382 escherichia coli;

the nucleotide sequence of the TdcC encoding gene is shown as SEQ ID NO. 2.

10. A genetic engineering strain is characterized in that the genetic engineering strain is preserved in the China general microbiological culture Collection center (China Committee for culture Collection of microorganisms) on the 5 th month of 2023, the preservation address is the North Chen West Lu No. 1, 3 of the Korean region of Beijing, the preservation number is CGMCC No.27382, and the strain is classified and named as Escherichia coli (Escherichia coli).