CN114836362A

CN114836362A - Method for improving immobilized fermentation of escherichia coli by applying fimH (fimH) in quorum sensing dynamic regulation and control system

Info

Publication number: CN114836362A
Application number: CN202210713019.5A
Authority: CN
Inventors: 陈勇; 侯安奇; 应汉杰; 陈天鹏; 孙文俊; 余斌; 柳东; 牛欢青
Original assignee: Nanjing Tech University
Current assignee: Nanjing Tech University
Priority date: 2022-06-22
Filing date: 2022-06-22
Publication date: 2022-08-02

Abstract

The invention discloses a method for improving immobilized fermentation of escherichia coli by applying pilus adhesion protein fimH to a quorum sensing dynamic regulation and control system, wherein escherichia coli genetic engineering bacteria introduce pUC19-PJ23119-MCS plasmid containing esaI/R system into escherichia coli BL21, and combine the plasmid with adhesion gene fimH. The invention combines the adhesion gene fimH related to the colibacillus film formation with the quorum sensing system esaI/R for the first time, controls the formation, decomposition and diffusion of the biological film through the signal transmission among quorum sensing signal molecules, establishes a specific regulation and control mode, accurately regulates and controls the formation process of the biological film in the fermentation process, strengthens the formation of the biological film in the early and middle stages of the fermentation, weakens the decomposition and diffusion in the later stage, and improves the immobilization efficiency and the catalytic efficiency of the biological film.

Description

Method for improving immobilized fermentation of escherichia coli by applying fimH (fimH) in quorum sensing dynamic regulation and control system

Technical Field

The invention relates to the field of biology, in particular to a method for improving immobilized fermentation of escherichia coli by applying pilus adhesion protein fimH to a quorum sensing dynamic regulation and control system.

Background

Biofilms (bifilms) are a form of microbial community in nature. The microorganisms gather together and secrete organic substances, such as polysaccharides, to cover the surface of the microorganisms, thereby forming a film-like substance. The microorganisms can better adapt to the external environment by forming the colony structure, and resist factors unfavorable for survival. In the medical field, the drug resistance of the bacteria is improved because the pathogenic bacteria often form a biological membrane, and the research on the biological membrane lasts for a long time. In the field of industrial fermentation applications, the mechanism of biofilm formation is relatively poorly studied. In particular to the molecular research aiming at the fermentation characteristics of the immobilized cells.

Adhesion proteins are a class of adhesion proteins that are widely found in gram bacteria. In gram-negative bacteria, the cell movement organ, which is composed of adhesion proteins, is called pilus. The role of these pili is mainly responsible for adhesion between bacterial cells, bacteria and non-biological surfaces, and is associated with biofilm formation and DNA transfer, among other things. The Escherichia coli has various types of pili, and a great deal of research shows that the I-type pili of the Escherichia coli promotes the biofilm formation in the process of forming the biofilm by the Escherichia coli, plays an important role in the reversible and non-reversible stages of the biofilm formation stage, and can enhance the adhesion characteristics among Escherichia coli cells and between cells and non-biological surfaces. The main key genes of the I-type pilus are regulated and controlled by a fim family, and comprise 9 genes such as fimA, fimH and the like, the fimH gene is the adhesin of the I-type pilus and is responsible for the adhesion with a non-biological surface, the I-type pilus also has an important function on the formation of an escherichia coli biofilm, and the fimA gene and the fimH gene are key genes for the formation of the escherichia coli biofilm.

Quorum Sensing (QS) is a bacterial cell-to-cell communication system, where microorganisms sense changes in the density of bacterial populations through secretion of diffusible small molecule signals, thereby causing coordinated expression of a set of specific genes at the transcriptional level. This communication allows the bacteria to express different physiological behaviors including regulation of bioluminescence, biofilm formation, toxin production, spore formation, and the like.

With the intensive research on quorum sensing action mechanism, the biological characteristic can be used for developing a cell density-dependent self-induced dynamic regulation tool. In E.coli, lacking genes responsible for the synthesis of AHLs with functions similar to LuxI, it is not able to produce AHL signal molecules by itself, but they encode LuxR homologous proteins and therefore can sense and respond to AHLs produced by other bacteria.

The AHL-mediated quorum sensing systems currently most studied and most widely used are mainly the luxI/luxR system from Vibrio fischeri and the esaI/esaR system from bacterial wilt disease of maize. Among gram-negative bacteria, the QS system, consisting of the luxI/luxR bi-component, is the most widely studied. Whereas the esaI/esaR system is homologous to the luxI/luxR system and originates from the maize pathogen Pantoea stewartii subspecies. Unlike most LuxR homologues, esaR can act as both a transcriptional activator and repressor, independent of whether binding to AHL signaling molecule occurs. In addition, Pesar is a native promoter that is repressed by esaR, and Pesas is a native promoter that is activated by esaR. At low cell densities, the cells produce less AHL signaling molecules and esaR binds to its target DNA sequence (esa box), turning on expression of the genes downstream of the PesaS promoter and turning off expression of the genes downstream of the PesaR promoter. At high cell densities, the cells produced more AHL signaling molecules and esaR released esa box binding to AHL, at which time the promoter PesaR was open and PesaS was closed.

Disclosure of Invention

The invention aims to: the technical problem to be solved by the invention is to provide a genetically engineered Escherichia coli strain containing quorum-sensing dynamic control biofilm formation, aiming at the defects of the prior art.

The technical problem to be solved by the invention is to provide a method for constructing the plasmid contained in the escherichia coli genetic engineering bacteria.

The invention further aims to solve the technical problem of providing the application of the escherichia coli genetic engineering bacteria.

The invention idea is as follows: the esaI/esaR system is homologous with the luxI/luxR system, and has a quorum sensing system with a bidirectional regulation function, and the adhesion gene fimH is proved to promote the formation of an escherichia coli biomembrane, so that the invention utilizes the fimH applied to the esaI/esaR system to realize the purpose of dynamic regulation.

In order to solve the first technical problem, the invention discloses an escherichia coli genetic engineering bacterium, wherein a pUC19-PJ23119-MCS plasmid containing an esaI/R system is introduced into escherichia coli BL21, and is combined with an adhesion gene fimH to be applied to improving the escherichia coli film forming amount and further improving the fermentation efficiency in immobilized fermentation.

Wherein, the gene contained in the esaI/R system is a transcription regulation factor with the nucleotide sequence respectively shown as SEQ ID NO.1 and SEQ ID NO. 2: esaI, esaR; the nucleotide sequences of the promoter are respectively shown as SEQ ID NO.3 and SEQ ID NO. 4: p _esaS 、P _esaR (ii) a The nucleotide sequences of the reporter genes are respectively shown as SEQ ID NO.5 and SEQ ID NO. 6: red fluorescent protein mCherry, green fluorescent protein EGFP.

Wherein the nucleotide sequence of fimH is shown as SEQ ID NO. 7.

In order to solve the second technical problem, the invention discloses a method for constructing the escherichia coli genetic engineering bacteria, which comprises the following steps:

(1) amplifying to obtain esaI and esaR genes by using pseudomonas aeruginosa genome DNA as a template; the gene P is synthesized by general biosynthesis _esaS 、P _esaR The PUC19 plasmid is used as a template to obtain P through amplification _esaS 、P _esaR A gene; amplifying by taking a plasmid pET28a-mCherry as a template to obtain an mCheerry gene; amplifying by taking the plasmid pET-28a-EGFP as a template to obtain an EGFP gene;

(2) taking the fragment obtained in the step (1) as a template, and carrying out overlap PCR amplification to obtain an esaI + esaR fragment and P _esaS + fimH + mCherry fragment, P _esaR + an EGFP fragment;

(3) cloning the gene fragment obtained in the step (2) between Hind III and Sac I restriction sites of plasmid pUC19-PJ23119-MCS to obtain recombinant plasmid pUC19-PJ23119-MCS-esaI/R, wherein the nucleotide sequence of the recombinant plasmid is shown as SEQ ID NO. 8;

(4) transforming the recombinant plasmid obtained in the step (3) into an escherichia coli T1 competence, and extracting, purifying and recovering the recombinant plasmid from escherichia coli T1;

(5) and (3) transforming the recombinant plasmid extracted in the step (4) into the competence of escherichia coli BL21 to obtain the escherichia coli genetic engineering bacteria.

In the step (1), primers for amplifying esaI and esaR genes are esaI-F, esaI-R, esaR-F, esaR-R with nucleotide sequences shown as SEQ ID NO.11, SEQ ID NO.12, SEQ ID NO.13 and SEQ ID NO.14 respectively.

In step (1), P is amplified _esaS 、P _esaR The primers of the gene are P with nucleotide sequences shown as SEQ ID NO.15, SEQ ID NO.16, SEQ ID NO.17 and SEQ ID NO.18 respectively _esaS -F、P _esaS -R、P _esaR -F、P _esaR -R。

In the step (1), primers for amplifying mCherry and EGFP genes are mChery-F, mCherry-R, EGFP-F, EGFP-R with nucleotide sequences shown as SEQ ID No.19, SEQ ID No.20, SEQ ID No.21 and SEQ ID No.22 respectively.

In order to solve the third technical problem, the invention discloses application of the large escherichia coli genetic engineering bacteria in xylanase production.

The xylanase is produced by replacing xylanase gene with nucleotide sequence shown in SEQ ID NO.23 to EGFP gene position in large Escherichia coli genetic engineering bacteria, and inoculating the bacteria to fermentation culture medium for fermentation.

Wherein the fermentation medium comprises 30g/L of glucose, 0.8g/L of sodium chloride, 20-22g/L of ammonium sulfate, 2g/L of anhydrous potassium dihydrogen phosphate, 0.8g/L of magnesium sulfate heptahydrate, 0.02g/L of manganese sulfate pentahydrate, 0.02g/L of ferric sulfate heptahydrate, 10.002g/L of vitamin B, 1g/L of yeast powder and 15-30g/L of calcium carbonate.

Has the advantages that: compared with the prior art, the invention has the following advantages:

the invention combines the adhesion gene fimH related to the colibacillus film formation with the quorum sensing system esaI/R for the first time, controls the formation, decomposition and diffusion of the biological film through the signal transmission among quorum sensing signal molecules, establishes a specific regulation and control mode, accurately regulates and controls the formation process of the biological film in the fermentation process, strengthens the formation of the biological film in the early and middle stages of the fermentation, weakens the decomposition and diffusion in the later stage, and improves the immobilization efficiency and the catalytic efficiency of the biological film.

Drawings

The foregoing and/or other advantages of the invention will become further apparent from the following detailed description of the invention when taken in conjunction with the accompanying drawings.

FIG. 1 shows fimH, esaI, esaR, P in example 1 _esaS 、P _esaR Agarose gel electrophoresis of genes mCherry and EGFP.

FIG. 2 depicts the esaI + esaR fragment, P, after OVERLAP in example 1 _esaS + fimH + mCherry fragment and P _esaR FIG. agarose gel electrophoresis of the EGFP fragment.

FIG. 3 is a schematic diagram of the construction of a recombinant expression plasmid in example 1.

FIG. 4 is a PCR scheme of plasmid-transformed colonies in example 1.

FIG. 5 is a graph showing the results of fluorescence microscopy in example 2.

FIG. 6 is a graph showing the results of fluorescence intensity detection by the microplate reader in example 3.

FIG. 7 is a graph showing the results of the crystal violet staining experiment in example 4.

FIG. 8 is a schematic diagram showing the results of the enzyme activity assay in example 5.

Detailed Description

The experimental methods described in the following examples are all conventional methods unless otherwise specified; the reagents and materials are commercially available, unless otherwise specified.

In the following embodiment, the Escherichia coli strain selected for the present invention is BL21, and Pseudomonas aeruginosa for the present invention is ATCC 15692.

Example 1: construction of the target Strain

First, amplification of target Gene

(1) Using the original genome of escherichia coli as a template, and using fimH-F, fimH-R (sequences are respectively shown as SEQ ID NO.9 and SEQ ID NO. 10) as a primer for amplification by using common PCR to obtain fimH; using pseudomonas aeruginosa genome DNA as a template, and using common PCR to amplify by using esaI-F, esaI-R, esaR-F, esaR-R (sequences are respectively shown as SEQ ID NO.11, SEQ ID NO.12, SEQ ID NO.13 and SEQ ID NO. 14) as primers to obtain esaI and esaR; the gene P is synthesized by general biosynthesis _esaS 、P _esaR The pUC19 plasmid was used as a template, and P was used as a template in the conventional PCR _esaS -F、P _esaS -R、P _esaR -F、P _esaR -R (the sequences are respectively shown as SEQ ID NO.15, SEQ ID NO.16, SEQ ID NO.17 and SEQ ID NO. 18) is used as a primer for amplification to obtain P _esaS 、P _esaR A gene; using plasmid pET28a-mCherry as a template, and using a common PCR to amplify by using mCherry-F, mCherry-R (sequences are respectively shown as SEQ ID NO.19 and SEQ ID NO. 20) as a primer to obtain a reporter gene mCheerry; the reporter gene EGFP is obtained by using plasmid pET-28a-EGFP as a template and EGFP-F, EGFP-R (sequences are respectively shown as SEQ ID NO.21 and SEQ ID NO. 22) as a primer through common PCR (polymerase chain reaction).

The PCR reaction system is shown in Table 1 below, and the reaction conditions are as follows: pre-denaturation at 95 ℃ for 4 min; denaturation at 94 ℃ for 10 s; annealing at 60 ℃ for 30 s; extending for 2min at 68 ℃; degeneration and regressionThe three steps of fire and extension are circulated for 35 times; further extension was carried out at 68 ℃ for 10 min. Wherein the annealing temperature depends on the Tm value of the primer, and the extension time at 68 ℃ depends on the length of the amplified fragment (1 kb/min). After the PCR was completed, the product was subjected to agarose gel electrophoresis, as shown in FIG. 1, and the objective genes fimH, esaI, esaR, P were recovered by cutting the gel _esaS 、P _esaR 、mCherry、EGFP。

TABLE 1 PCR reaction System

(2) Using the esaI gene and the esaR gene obtained in the step (1) as templates, using esaI-F as an upper primer and esaR-R as a lower primer, and amplifying by using an overlap PCR technology to obtain an esaI + esaR fragment; with P obtained in step (1) _esaS The gene, fimH gene and mCherry gene are used as templates and P is used _esaS F is an upper primer, mchery-R is a lower primer, and P is obtained by applying overlap PCR technology to amplify _esaS + fimH + mCherry fragment; with P obtained in step (1) _esaR Gene and EGFP gene as template, using P _esaR F is an upper primer, EGFP-R is a lower primer, and P is obtained by amplification by using overlap PCR technology _esaR + an EGFP fragment;

the PCR reaction system is shown in Table 3 below, and the reaction conditions are as follows: pre-denaturation at 95 ℃ for 4 min; denaturation at 94 ℃ for 10 s; annealing at 60 ℃ for 30 s; extending for 2min at 68 ℃; three steps of denaturation, annealing and extension are cycled for 30 times; further extension was carried out at 68 ℃ for 10 min. Wherein the annealing temperature depends on the Tm value of the primer, and the extension time at 68 ℃ depends on the length of the amplified fragment (1 kb/min). After the PCR was completed, the product was subjected to agarose gel electrophoresis, see FIG. 2, and the three fragment modules esaI + esaR fragment and P were recovered by cutting the gel _esaS + fimH + mCherry fragment and P _esaR + EGFP fragment.

TABLE 2 PCR reaction System

Second, construction of recombinant plasmid

(1) Plasmid extracting body

Coli DH 5. alpha. glycerol strain (containing plasmid pUC19-PJ23119-MCS) was inoculated to liquid LB (ampicillin resistant, 100. mu.g/mL) and cultured at 37 ℃ for 12 hours. The cells cultured in the previous step were collected in a 1.5mL centrifuge tube, centrifuged at 10000rpm for 2min, and the supernatant was removed. Plasmid pUC19-PJ23119-MCS was extracted according to the AxyPrep plasmid extraction kit of Corning Life sciences Ltd.

(2) Linearization of vectors

To fragment the gene of interest (esaI + esaR, P) _esaS + mCherry and P _esaR + EGFP) was ligated to plasmid pUC19-PJ23119-MCS, which was digested in a double digestion reaction system (20. mu.L) of 0.1% BSA 2. mu.L, 1. mu.M buffer 2. mu.L, 0.5. mu.L each of HindIII and SacI enzymes (from TAKARA), plasmid pUC19-PJ23119-MCS 10. mu.L, sterile water 5. mu.L. The enzyme digestion reaction is carried out for 2h at 37 ℃. And (4) carrying out gel recovery after enzyme digestion for subsequent experiments.

Wherein, the buffer: 10 × Loading buffer: 0.9% SDS, 50% glycocol, 0.05% Bromophenol Blue;

the Hind iii enzyme: restriction enzyme

The SacI enzyme: restriction enzyme

Definition of enzyme activity: the reaction was carried out at 37 ℃ for 1 hour in 50. mu.L of the reaction solution, and the amount of the enzyme that completely decomposed 1. mu.g of lambda.DNA was defined as 1 activity unit (U).

(3) Construction of plasmid pUC19-PJ23119-MCS-esaI/R

The three fragments (esaI + esaR, P) _esaS + mCherry and P _esaR + EGFP) was ligated to the purified linear vector following the procedures described in the NEB's multiple fragment one-step cloning of the enzyme to obtain the recombinant plasmid pUC19-PJ23119-MCS-esaI/R (SEQ ID NO. 8). The one-step cloning reaction system is shown in Table 3, and after a water bath at 50 ℃ for 15 minutes, the reaction system is immediately subjected to an ice bath for 5 minutesStoring at-20 deg.C. A schematic diagram of the construction of the recombinant expression plasmid is shown in FIG. 3.

TABLE 3 Multi-fragment one-step cloning reaction System

Wherein the plasmid pUC19-PJ23119-MCS after double digestion, the purified gene fragment esaI + esaR and the purified gene fragment P _esaS + fimH + mCherry, purified gene fragment P _esaR + EGFP concentration 100 ng/. mu.l.

(4) Transformation and selection of recombinant plasmids

Taking out the TI competent cells, thawing the TI competent cells to be liquid on ice, and adding the competent cells and the recombinant plasmid pUC19-PJ23119-MCS-esaI/R in a ratio of 10:1v/v into a precooling centrifuge tube. The mixture was kept on ice for 30min, and heat-shocked in a water bath at 42 ℃ for 90 sec. The ice box was cooled for 3 minutes, added with 1mL LB at 37 degrees C, 200rpm culture for 1 hours, centrifugal removal of most of the supernatant heavy suspension bacteria liquid and ampicillin resistance plate. After overnight incubation in an incubator at 37 ℃, single spots on the plates were picked, 100. mu.g/mL ampicillin resistance in the shake tube was added, and then the plasmid pUC19-PJ23119-MCS-esaI/R was extracted for sequencing validation.

Third, construction of recombinant strains

After the recombinant plasmid is successfully verified, an esaI/R system-containing strain is constructed and named as Escherichia coli BL 21-R. The successfully verified plasmids are transferred into the competence of escherichia coli BL21 by the same transformation method, and a single colony is picked for colony PCR verification. The results of colony PCR experiments are shown in FIG. 4, and it can be seen that the transformation was successful.

Example 2: carrying out fluorescence microscope observation on original bacteria BL21 and modified bacteria BL21-R

(1) 100. mu.L of each of glycerol strain WT (original strain BL21) and modified strain BL21-R (strain containing esaI/R system constructed in example 1) was added to 5mL of sterilized LB liquid medium for overnight culture (ampicillin resistance, 100. mu.g/mL), and activated;

(2) according to the volume ratio of 1: 10, transferring the activated bacterial liquid obtained in the step (1) to 100mL of LB liquid medium (ampicillin resistance, 100. mu.g/mL; 3mL of 1M L-arabinose was added as appropriate for induction), and continuing the culture at 37 ℃ and 220rpm for 13 hours;

(3) and (3) sampling the bacterial liquid cultured in the step (2), and then directly observing under a fluorescence microscope, wherein the fluorescence microscope result is shown in FIG. 5, which shows that the original transformed bacterium has no luminescence, and the transformed bacterium has luminescence, and shows that the esaI/R system of the transformed bacterium BL21-R is established without errors.

Example 3: fluorescence intensity detection experiment of enzyme labeling instrument for modified bacteria BL21-R

(1) Since the original bacterium BL21 did not emit light in the fluorescence microscope observation, only the modified bacterium was detected in the fluorescence intensity detection experiment. The modified strain BL21-R (the strain containing the esaI/R system constructed in example 1) was added to a sterilized 5mL LB liquid medium in an amount of 100. mu.L for overnight culture (ampicillin resistance, 100. mu.g/mL), and activated;

(2) according to the volume ratio of 1: 10, transferring the activated bacterial liquid obtained in the step (1) to 100mL of LB liquid medium (ampicillin resistance, 100 mu g/mL), continuously culturing at 37 ℃ and 220rpm, and taking samples every 4 hours for 48 hours;

(3) the well-taken sample is diluted by 20 times by PBS buffer solution, 200 mu L of the diluted sample is added into a 96-well plate, and detection is carried out by a microplate reader at different wavelengths respectively: detecting the green fluorescence intensity of 485nm excitation wavelength and 528nm emission wavelength, and detecting the red fluorescence intensity of 587nm excitation wavelength and 610nm emission wavelength. The fluorescence intensity is shown in fig. 6, the red fluorescence (mCherry) is stronger in the early stage, the green fluorescence (EGFP) is stronger in the later stage, and the fluorescent material accords with the process of an esaI/R system and the experimental design concept, and can be applied in the next step.

Example 4: biofilm crystal violet staining experiment

1) 100. mu.L of each of glycerol strain WT (original strain BL21) and modified strain BL21-R (strain containing esaI/R system constructed in example 1) was added to 5mL of sterilized LB liquid medium for overnight culture (ampicillin resistance, 100. mu.g/mL), and activated;

(2) according to the volume ratio of 1: 10, transferring the activated bacterium liquid obtained in the step (1) to 100mL of LB liquid culture medium, and continuously culturing at 37 ℃ and 220rpm until the OD600 value of the bacterium liquid is between 0.8 and 1.2;

(3) measuring the absorbance value of 2mL of bacterial liquid under OD600, and diluting the bacterial liquid by using a sterilized LB liquid culture medium to enable the OD600 of the diluted bacterial liquid to be 1;

(4) adding 200 mu L of diluted bacterial liquid into a 96-well plate, using a liquid culture medium as a reference, and culturing at 37 ℃ for 12h, 24h and 36 h;

(5) pouring out the bacterial liquid in the 96-well plate, taking 200 mu L of 0.01M PBS buffer solution to wash for 2-3 times, and patting dry;

(6) adding 200 μ L paraformaldehyde fixing solution, fixing for 15min, pouring off, and air drying.

(7) Adding 200 μ L of 1% crystal violet solution into 96-well plate, staining for 10-20min, washing with PBS buffer solution for 2-3 times, and drying;

(8) adding 200 μ L glacial acetic acid into 96-well plate to dissolve the biofilm, gently shaking for 40min, measuring OD570nm biofilm yield, and taking average value. The crystal violet staining experiment result is shown in fig. 7, the original bacteria biofilm amount is 0.3786, the modified bacteria biofilm amount is 0.9649, and the modified bacteria biofilm amount is improved by 2.54 times, which shows that the modified strain BL21-R biofilm is obviously increased, and the biological membrane immobilization fermentation experiment can be carried out.

Example 5: application of modified bacteria BL21-R in immobilized fermentation for producing xylanase

(1) The xylanase gene xyn (derived from Thermoanaerobacterium Thermoanaerobacterium thermosaccharolyticum M5) was replaced in the position of the EGFP gene.

Alternatively, EGFP of the recombinant plasmid is cut off by using an enzyme cleavage site and then xyn is connected by one-step cloning by using a one-step cloning kit C112 of Novozam, and the specific steps are similar to the step (3) of the example 1 to obtain the strain BL 21-R-xyn.

Meanwhile, a strain WT-xyn only containing xyn genes is constructed (the method is the same as the method, and the used plasmid is an empty plasmid PUC19 without esaI/R system).

(2) Immobilizing the bacteria obtained in the step (1) for fermentation to produce xylanase

WT-xyn and BL21-R-xyn were removed from a freezer at-80 ℃ and 5mL of LB medium was prepared in tubes, one bottle containing 100. mu.g/mL ampicillin at 1% inoculum size. Culturing in a shaker at 37 deg.C for 12h at 200rpm to obtain bacterial liquid.

The resulting bacterial solution was diluted to OD 0.1 and inoculated into 100mL LB fermentation medium (5 g square cotton fibers were placed in the medium in advance), and cultured in a shaker at 37 ℃ for 36h at 200 and 220 rpm.

Wherein, the LB fermentation medium: 30g/L of glucose, 0.8g/L of sodium chloride, 20g/L of ammonium sulfate, 2g/L of anhydrous potassium dihydrogen phosphate, 0.8g/L of magnesium sulfate heptahydrate, 0.02g/L of manganese sulfate pentahydrate, 0.02g/L of ferric sulfate heptahydrate, 10.002g/L of vitamin B, 1g/L of yeast powder and 15g/L of calcium carbonate.

The detection method comprises the following steps: the xylanase activity is determined by a dinitrosalicylic acid method (DNS), dinitrosalicylic acid and reducing sugar can generate oxidation-reduction reaction to generate 3-amino-5-nitro salicylic acid, the product is brownish red under boiling condition, and the color depth is in a proportional relation with the content of the reducing sugar within a certain concentration range. The reaction process is as follows: 1mL of enzyme solution (diluted by a certain amount if necessary) and 1mL of 1% xylan (dissolved in PBS buffer solution with pH 6.0) were reacted in a water bath at 55 ℃ for 10min, then 2mL of DNS solution was added, and the mixture was subjected to a boiling water bath for 5min to obtain a volume of 25mL, and A540 was measured. Definition of enzyme activity (U): the amount of enzyme required to produce 1. mu.M xylose per minute.

The enzyme activity test result is shown in figure 8, the enzyme activity of the original strain WT-xyn is measured to be 0.55U/mg, the enzyme activity of the modified strain BL21-R-xyn is measured to be 0.97U/mg, and the enzyme activity of the modified strain is improved by 1.76 times.

The invention provides an escherichia coli genetic engineering bacterium containing an esaI/R quorum sensing system, and a construction method and application thereof, the above description is only a preferred embodiment of the invention, and it should be noted that, for a person skilled in the art, a plurality of improvements and modifications can be made without departing from the principle of the invention, and these improvements and modifications should also be regarded as the protection scope of the invention. All the components not specified in the present embodiment can be realized by the prior art.

Sequence listing

<110> Nanjing university of industry

<120> method for improving immobilized fermentation of escherichia coli by applying fimH (fimH) to quorum sensing dynamic regulation and control system

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<400> 5

atggtgagca agggcgagga ggataacatg gccatcatca aggagttcat gcgcttcaag 60

gtgcacatgg agggctccgt gaacggccac gagttcgaga tcgagggcga gggcgagggc 120

cgcccctacg agggcaccca gaccgccaag ctgaaggtga ccaagggtgg ccccctgccc 180

ttcgcctggg acatcctgtc ccctcagttc atgtacggct ccaaggccta cgtgaagcac 240

cccgccgaca tccccgacta cttgaagctg tccttccccg agggcttcaa gtgggagcgc 300

gtgatgaact tcgaggacgg cggcgtggtg accgtgaccc aggactcctc cctgcaggac 360

ggcgagttca tctacaaggt gaagctgcgc ggcaccaact tcccctccga cggccccgta 420

atgcagaaga agaccatggg ctgggaggcc tcctccgagc ggatgtaccc cgaggacggc 480

gccctgaagg gcgagatcaa gcagaggctg aagctgaagg acggcggcca ctacgacgct 540

gaggtcaaga ccacctacaa ggccaagaag cccgtgcagc tgcccggcgc ctacaacgtc 600

aacatcaagt ttctagagga catcacctcc cacaacgagg actacaccat cgtggaacag 660

tacgaacgcg ccgagggccg ccactccacc ggcggcatgg acgagctgta caagtaa 717

<210> 6

<211> 720

<212> DNA

<213> EGFP

<400> 6

atggtgagca agggcgagga gctgttcacc ggggtggtgc ccatcctggt cgagctggac 60

ggcgacgtaa acggccacaa gttcagcgtg tccggcgagg gcgagggcga tgccacctac 120

ggcaagctga ccctgaagtt catctgcacc accggcaagc tgcccgtgcc ctggcccacc 180

ctcgtgacca ccctgaccta cggcgtgcag tgcttcagcc gctaccccga ccacatgaag 240

cagcacgact tcttcaagtc cgccatgccc gaaggctacg tccaggagcg caccatcttc 300

ttcaaggacg acggcaacta caagacccgc gccgaggtga agttcgaggg cgacaccctg 360

gtgaaccgca tcgagctgaa gggcatcgac ttcaaggagg acggcaacat cctggggcac 420

aagctggagt acaactacaa cagccacaac gtctatatca tggccgacaa gcagaagaac 480

ggcatcaagg tgaacttcaa gatccgccac aacatcgagg acggcagcgt gcagctcgcc 540

gaccactacc agcagaacac ccccatcggc gacggccccg tgctgctgcc cgacaaccac 600

tacctgagca cccagtccgc cctgagcaaa gaccccaacg agaagcgcga tcacatggtc 660

ctgctggagt tcgtgaccgc cgccgggatc actctcggca tggacgagct gtacaagtaa 720

<210> 7

<211> 903

<212> DNA

<213> fimH

<400> 7

atgaaacgag ttattaccct gtttgctgta ctgctgatgg gctggtcggt aaatgcctgg 60

tcattcgcct gtaaaaccgc caatggtacc gctatcccta ttggcggtgg cagcgccaat 120

gtttatgtaa accttgcgcc cgtcgtgaat gtggggcaaa acctggtcgt ggatctttcg 180

acgcaaatct tttgccataa cgattatccg gaaaccatta cagactatgt cacactgcaa 240

cgaggctcgg cttatggcgg cgtgttatct aatttttccg ggaccgtaaa atatagtggc 300

agtagctatc catttcctac caccagcgaa acgccgcgcg ttgtttataa ttcgagaacg 360

gataagccgt ggccggtggc gctttatttg acgcctgtga gcagtgcggg cggggtggcg 420

attaaagctg gctcattaat tgccgtgctt attttgcgac agaccaacaa ctataacagc 480

gatgatttcc agtttgtgtg gaatatttac gccaataatg atgtggtggt gcctactggc 540

ggctgcgatg tttctgctcg tgatgtcacc gttactctgc cggactaccc tggttcagtg 600

ccaattcctc ttaccgttta ttgtgcgaaa agccaaaacc tggggtatta cctctccggc 660

acaaccgcag atgcgggcaa ctcgattttc accaataccg cgtcgttttc acctgcacag 720

ggcgtcggcg tacagttgac gcgcaacggt acgattattc cagcgaataa cacggtatcg 780

ttaggagcag tagggacttc ggcggtgagt ctgggattaa cggcaaatta tgcacgtacc 840

ggagggcagg tgactgcagg gaatgtgcaa tcgattattg gcgtgacttt tgtttatcaa 900

taa 903

<210> 8

<211> 6959

<212> DNA

<213> pUC19-PJ23119-MCS-esaI/R

<400> 8

gcgcccaata cgcaaaccgc ctctccccgc gcgttggccg attcattaat gcagctggca 60

cgacaggttt cccgactgga aagcgggcag tgagcgcaac gcaattaatg tgagttagct 120

cactcattag gcaccccagg cttgacagct agctcagtcc taggtataat actagttttc 180

acacaggaaa cagctatgac catgattacg ccaagcttaa gaaaccaatt gtccatattg 240

catcagacat tgccgtcact gcgtctttta ctggcacttc tcgctaacca aaccggtaac 300

cccgcttatt aaaagcattc tgtaacaaag cgggaccaaa gccatgacaa aaacgcgtaa 360

caaaagtgtc tataatcacg gcagaaaagt ccacattgat tatttgcacg gcgtcacact 420

ttgctatgcc atagcatttt tatccataag attagcggat cctacctgac gctttttatc 480

gcaactctct actgtttctc catgtcgaca tgatcgtaca aattggtcgg cgcgaagagt 540

tcgataaaaa actgctgggc gagatgcaca agttgcgtgc tcaagtgttc aaggagcgca 600

aaggctggga cgttagtgtc atcgacgaga tggaaatcga tggttatgac gcactcagtc 660

cttattacat gttgatccag gaagatactc ctgaagccca ggttttcggt tgctggcgaa 720

ttctcgatac cactggcccc tacatgctga agaacacctt cccggagctt ctgcacggca 780

aggaagcgcc ttgctcgccg cacatctggg aactcagccg tttcgccatc aactctggac 840

agaaaggctc gctgggcttt tccgactgta cgctggaggc gatgcgcgcg ctggcccgct 900

acagcctgca gaacgacatc cagacgctgg tgacggtaac caccgtaggc gtggagaaga 960

tgatgatccg tgccggcctg gacgtatcgc gcttcggtcc gcacctgaag atcggcatcg 1020

agcgcgcggt ggccttgcgc atcgaactca atgccaagac ccagatcgcg ctttacgggg 1080

gagtgctggt ggaacagcga ctggcggttt catgataatg tgagttagct cactcattag 1140

gcaccccagg cttgacagct agctcagtcc taggtataat actagtatgg ccttggttga 1200

cggttttctt gagctggaac gctcaagtgg aaaattggag tggagcgcca tcctgcagaa 1260

gatggcgagc gaccttggat tctcgaagat cctgttcggc ctgttgccta aggacagcca 1320

ggactacgag aacgccttca tcgtcggcaa ctacccggcc gcctggcgcg agcattacga 1380

ccgggctggc tacgcgcggg tcgacccgac ggtcagtcac tgtacccaga gcgtactgcc 1440

gattttctgg gaaccgtcca tctaccagac gcgaaagcag cacgagttct tcgaggaagc 1500

ctcggccgcc ggcctggtgt atgggctgac catgccgctg catggtgctc gcggcgaact 1560

cggcgcgctg agcctcagcg tggaagcgga aaaccgggcc gaggccaacc gtttcatgga 1620

gtcggtcctg ccgaccctgt ggatgctcaa ggactacgca ctgcagagcg gtgccggact 1680

ggccttcgaa catccggtca gcaaaccggt ggttctgacc agccgggaga aggaagtgtt 1740

gcagtggtgc gccatcggca agaccagttg ggagatatcg gttatctgca actgctcgga 1800

agccaatgtg aacttccata tgggaaatat tcggcggaag ttcggtgtga cctcccgccg 1860

cgtagcggcc attatggccg ttaatttggg tcttattact ctctgagcat gcgctcacaa 1920

cagtgtaagc gtatccgtta ttgtttgatt ttcaaggaaa aaagaaaaca ttcaggctcc 1980

atgctgcttc ttttacttaa cgtggactta acctgcacta tagtacaggc aagatgatac 2040

ttaagagtaa cttacaatga atcattcaga ggttacaatg gcttcagttg tttagcgtcg 2100

acatgaaacg agttattacc ctgtttgctg tactgctgat gggctggtcg gtaaatgcct 2160

ggtcattcgc ctgtaaaacc gccaatggta ccgctatccc tattggcggt ggcagcgcca 2220

atgtttatgt aaaccttgcg cccgtcgtga atgtggggca aaacctggtc gtggatcttt 2280

cgacgcaaat cttttgccat aacgattatc cggaaaccat tacagactat gtcacactgc 2340

aacgaggctc ggcttatggc ggcgtgttat ctaatttttc cgggaccgta aaatatagtg 2400

gcagtagcta tccatttcct accaccagcg aaacgccgcg cgttgtttat aattcgagaa 2460

cggataagcc gtggccggtg gcgctttatt tgacgcctgt gagcagtgcg ggcggggtgg 2520

cgattaaagc tggctcatta attgccgtgc ttattttgcg acagaccaac aactataaca 2580

gcgatgattt ccagtttgtg tggaatattt acgccaataa tgatgtggtg gtgcctactg 2640

gcggctgcga tgtttctgct cgtgatgtca ccgttactct gccggactac cctggttcag 2700

tgccaattcc tcttaccgtt tattgtgcga aaagccaaaa cctggggtat tacctctccg 2760

gcacaaccgc agatgcgggc aactcgattt tcaccaatac cgcgtcgttt tcacctgcac 2820

agggcgtcgg cgtacagttg acgcgcaacg gtacgattat tccagcgaat aacacggtat 2880

cgttaggagc agtagggact tcggcggtga gtctgggatt aacggcaaat tatgcacgta 2940

ccggagggca ggtgactgca gggaatgtgc aatcgattat tggcgtgact tttgtttatc 3000

aataaatggt gagcaagggc gaggaggata acatggccat catcaaggag ttcatgcgct 3060

tcaaggtgca catggagggc tccgtgaacg gccacgagtt cgagatcgag ggcgagggcg 3120

agggccgccc ctacgagggc acccagaccg ccaagctgaa ggtgaccaag ggtggccccc 3180

tgcccttcgc ctgggacatc ctgtcccctc agttcatgta cggctccaag gcctacgtga 3240

agcaccccgc cgacatcccc gactacttga agctgtcctt ccccgagggc ttcaagtggg 3300

agcgcgtgat gaacttcgag gacggcggcg tggtgaccgt gacccaggac tcctccctgc 3360

aggacggcga gttcatctac aaggtgaagc tgcgcggcac caacttcccc tccgacggcc 3420

ccgtaatgca gaagaagacc atgggctggg aggcctcctc cgagcggatg taccccgagg 3480

acggcgccct gaagggcgag atcaagcaga ggctgaagct gaaggacggc ggccactacg 3540

acgctgaggt caagaccacc tacaaggcca agaagcccgt gcagctgccc ggcgcctaca 3600

acgtcaacat caagtttcta gaggacatca cctcccacaa cgaggactac accatcgtgg 3660

aacagtacga acgcgccgag ggccgccact ccaccggcgg catggacgag ctgtacaagt 3720

aattgtaacc tctgaatgat tcattgtaag ttactcttaa gtatcatctt gcctgtacta 3780

tagtgcaggt taagtccacg ttaagtaaaa gaagcagcgg atccctcgag atggtgagca 3840

agggcgagga gctgttcacc ggggtggtgc ccatcctggt cgagctggac ggcgacgtaa 3900

acggccacaa gttcagcgtg tccggcgagg gcgagggcga tgccacctac ggcaagctga 3960

ccctgaagtt catctgcacc accggcaagc tgcccgtgcc ctggcccacc ctcgtgacca 4020

ccctgaccta cggcgtgcag tgcttcagcc gctaccccga ccacatgaag cagcacgact 4080

tcttcaagtc cgccatgccc gaaggctacg tccaggagcg caccatcttc ttcaaggacg 4140

acggcaacta caagacccgc gccgaggtga agttcgaggg cgacaccctg gtgaaccgca 4200

tcgagctgaa gggcatcgac ttcaaggagg acggcaacat cctggggcac aagctggagt 4260

acaactacaa cagccacaac gtctatatca tggccgacaa gcagaagaac ggcatcaagg 4320

tgaacttcaa gatccgccac aacatcgagg acggcagcgt gcagctcgcc gaccactacc 4380

agcagaacac ccccatcggc gacggccccg tgctgctgcc cgacaaccac tacctgagca 4440

cccagtccgc cctgagcaaa gaccccaacg agaagcgcga tcacatggtc ctgctggagt 4500

tcgtgaccgc cgccgggatc actctcggca tggacgagct gtacaagtaa gagctcgaat 4560

tcactggccg tcgttttaca acgtcgtgac tgggaaaacc ctggcgttac ccaacttaat 4620

cgccttgcag cacatccccc tttcgccagc tggcgtaata gcgaagaggc ccgcaccgat 4680

cgcccttccc aacagttgcg cagcctgaat ggcgaatggc gcctgatgcg gtattttctc 4740

cttacgcatc tgtgcggtat ttcacaccgc atatggtgca ctctcagtac aatctgctct 4800

gatgccgcat agttaagcca gccccgacac ccgccaacac ccgctgacgc gccctgacgg 4860

gcttgtctgc tcccggcatc cgcttacaga caagctgtga ccgtctccgg gagctgcatg 4920

tgtcagaggt tttcaccgtc atcaccgaaa cgcgcgagac gaaagggcct cgtgatacgc 4980

ctatttttat aggttaatgt catgataata atggtttctt agacgtcagg tggcactttt 5040

cggggaaatg tgcgcggaac ccctatttgt ttatttttct aaatacattc aaatatgtat 5100

ccgctcatga gacaataacc ctgataaatg cttcaataat attgaaaaag gaagagtatg 5160

agtattcaac atttccgtgt cgcccttatt cccttttttg cggcattttg ccttcctgtt 5220

tttgctcacc cagaaacgct ggtgaaagta aaagatgctg aagatcagtt gggtgcacga 5280

gtgggttaca tcgaactgga tctcaacagc ggtaagatcc ttgagagttt tcgccccgaa 5340

gaacgttttc caatgatgag cacttttaaa gttctgctat gtggcgcggt attatcccgt 5400

attgacgccg ggcaagagca actcggtcgc cgcatacact attctcagaa tgacttggtt 5460

gagtactcac cagtcacaga aaagcatctt acggatggca tgacagtaag agaattatgc 5520

agtgctgcca taaccatgag tgataacact gcggccaact tacttctgac aacgatcgga 5580

ggaccgaagg agctaaccgc ttttttgcac aacatggggg atcatgtaac tcgccttgat 5640

cgttgggaac cggagctgaa tgaagccata ccaaacgacg agcgtgacac cacgatgcct 5700

gtagcaatgg caacaacgtt gcgcaaacta ttaactggcg aactacttac tctagcttcc 5760

cggcaacaat taatagactg gatggaggcg gataaagttg caggaccact tctgcgctcg 5820

gcccttccgg ctggctggtt tattgctgat aaatctggag ccggtgagcg tgggtctcgc 5880

ggtatcattg cagcactggg gccagatggt aagccctccc gtatcgtagt tatctacacg 5940

acggggagtc aggcaactat ggatgaacga aatagacaga tcgctgagat aggtgcctca 6000

ctgattaagc attggtaact gtcagaccaa gtttactcat atatacttta gattgattta 6060

aaacttcatt tttaatttaa aaggatctag gtgaagatcc tttttgataa tctcatgacc 6120

aaaatccctt aacgtgagtt ttcgttccac tgagcgtcag accccgtaga aaagatcaaa 6180

ggatcttctt gagatccttt ttttctgcgc gtaatctgct gcttgcaaac aaaaaaacca 6240

ccgctaccag cggtggtttg tttgccggat caagagctac caactctttt tccgaaggta 6300

actggcttca gcagagcgca gataccaaat actgttcttc tagtgtagcc gtagttaggc 6360

caccacttca agaactctgt agcaccgcct acatacctcg ctctgctaat cctgttacca 6420

gtggctgctg ccagtggcga taagtcgtgt cttaccgggt tggactcaag acgatagtta 6480

ccggataagg cgcagcggtc gggctgaacg gggggttcgt gcacacagcc cagcttggag 6540

cgaacgacct acaccgaact gagataccta cagcgtgagc tatgagaaag cgccacgctt 6600

cccgaaggga gaaaggcgga caggtatccg gtaagcggca gggtcggaac aggagagcgc 6660

acgagggagc ttccaggggg aaacgcctgg tatctttata gtcctgtcgg gtttcgccac 6720

ctctgacttg agcgtcgatt tttgtgatgc tcgtcagggg ggcggagcct atggaaaaac 6780

gccagcaacg cggccttttt acggttcctg gccttttgct ggccttttgc tcacatgttc 6840

tttcctgcgt tatcccctga ttctgtggat aaccgtatta ccgcctttga gtgagctgat 6900

accgctcgcc gcagccgaac gaccgagcgc agcgagtcag tgagcgagga agcggaaga 6959

<210> 9

<211> 47

<212> DNA

<213> fimH-F

<400> 9

caatggcttc agttgtttag cgtcgacatg aaacgagtta ttaccct 47

<210> 10

<211> 47

<212> DNA

<213> fimH-R

<400> 10

atcctcctcg cccttgctca ccatttattg ataaacaaaa gtcacgc 47

<210> 11

<211> 50

<212> DNA

<213> esaI-F

<400> 11

gcaactctct actgtttctc catgtcgaca tgatcgtaca aattggtcgg 50

<210> 12

<211> 65

<212> DNA

<213> esaI-R

<400> 12

gtcaaccaag gccatactag tattatacct aggactgagc tagctgtcaa tcatgaaacc 60

gccag 65

<210> 13

<211> 65

<212> DNA

<213> esaR-F

<400> 13

ctggcggttt catgattgac agctagctca gtcctaggta taatactagt atggccttgg 60

ttgac 65

<210> 14

<211> 37

<212> DNA

<213> esaR-R

<400> 14

gcatgctcag agagtaataa gacccaaatt aacggcc 37

<210> 15

<211> 46

<212> DNA

<213> PesaS-F

<400> 15

tgggtcttat tactctctga gcatgcgctc acaacagtgt aagcgt 46

<210> 16

<211> 47

<212> DNA

<213> PesaS-R

<400> 16

agggtaataa ctcgtttcat gtcgacgcta aacaactgaa gccattg 47

<210> 17

<211> 42

<212> DNA

<213> PesaR-F

<400> 17

ctacaacgtc aacatcaagt ttctagagga catcacctcc ca 42

<210> 18

<211> 36

<212> DNA

<213> PesaR-R

<400> 18

gagctgtaca agtaactcga gggatccgct gcttct 36

<210> 19

<211> 47

<212> DNA

<213> mcherry-F

<400> 19

gcgtgacttt tgtttatcaa taaatggtga gcaagggcga ggaggat 47

<210> 20

<211> 26

<212> DNA

<213> mcherry-R

<400> 20

tctagattac ttgtacagct cgtcca 26

<210> 21

<211> 47

<212> DNA

<213> EGFP-F

<400> 21

agaagcagcg gatccctcga gatggtgagc aagggcgagg agctgtt 47

<210> 22

<211> 50

<212> DNA

<213> EGFP-R

<400> 22

cgacggccag tgaattcgag ctcttacttg tacagctcgt ccatgccgag 50

<210> 23

<211> 1242

<212> DNA

<213> xyn

<400> 23

atgaatgcgg atgctgcaga taaattaaaa caccgcaaag gaatcgccaa aataaagtta 60

gttaagaaag atggttcacc tataaaagat gcagaagtcg ctgtatctca ggtgaagcat 120

aaatttttat ttggttgtgg agcatttgat tctcttcctc ttgccaatgg tgaattgaaa 180

gaaaatgata aagaaaaaat tgaagaccgt tttgagaaat tttttgactt atttaactat 240

gctacgattc cattttattg gggcaggttc gagcctgaaa aaggaaagcc agacacaaat 300

agactcaaaa aggcttcaga atggcttgta tcaaaaggtt gccttgtaaa aggccatcca 360

ctttgctggc atactgtaac agcaccttgg cttttagata tgaacaatga agacatatta 420

aaggctcagc tatcccgcat aaaacgtgaa gtaagcgatt ttaaaggatt agtgaatata 480

tgggatgtaa taaatgaagt tgtcatcatg cctatttttg ataaatacga caatggaata 540

accaggatat gcaaagaatt aggccgtatt cgcctcgtaa aagaagtttt taatgaagct 600

aaaaaagcta atcctgaagc agttctcctt ataaatgact ttaatacatc aatttcatac 660

gaaatactca tagaaggatg ccttgaagct ggaatcccta ttgatgccat aggaattcag 720

tcacacatgc atcaaggata ttggggagtt gaaaaaactt tagaagtact tgaaagattt 780

tcgcatttca acattccatt gcattttaca gaaaacacat tattatcagg gcatttgatg 840

ccacctgaaa tagaagactt aaatgactac cagataaggg attggccttc aacacctgat 900

ggtgaagaac gacaagcgat ggaaatagta cagcattaca aaactctttt ttcacatcca 960

atggtagaat caattacgtg gtggaatttt tgtgatgaaa atgcatggct tggtgcacca 1020

gcaggtcttt tacgccgtga caattcatgc aaaccatcat attacgaatt aaaaaagctt 1080

ataaaagatg aatggtggac acatcctaca cgtcttgtca caagtaacac aggcgaattt 1140

gaatttacag gtttcttagg cgaatacgaa ttagtcatta gcgataaaag gttttacttt 1200

acccttgata aaaacagcac aacaattgaa atcacgattt aa 1242

Claims

1. An escherichia coli genetic engineering bacterium is characterized in that pUC19-PJ23119-MCS plasmid containing esaI/R system is introduced into escherichia coli BL21 and combined with adhesion gene fimH.

2. The escherichia coli genetically engineered bacterium of claim 1, wherein the gene contained in the esaI/R system is a transcription regulatory factor having a nucleotide sequence shown in SEQ ID No.1 and SEQ ID No.2, respectively: esaI, esaR; the nucleotide sequences of the promoter are respectively shown as SEQ ID NO.3 and SEQ ID NO. 4: p _esaS 、P _esaR (ii) a The nucleotide sequences of the reporter genes are respectively shown as SEQ ID NO.5 and SEQ ID NO. 6: red fluorescent protein mCherry, green fluorescent protein EGFP.

3. The engineered Escherichia coli strain of claim 1, wherein the nucleotide sequence of fimH is represented by SEQ ID NO. 7.

4. The method for constructing the Escherichia coli genetically engineered bacterium of any one of claims 1 to 3, comprising the steps of:

5. The method of claim 4, wherein in step (1), primers for amplifying esaI and esaR genes are esaI-F, esaI-R, esaR-F, esaR-R with nucleotide sequences shown in SEQ ID NO.11, SEQ ID NO.12, SEQ ID NO.13 and SEQ ID NO.14, respectively.

6. The method of claim 4, wherein in step (1), P is amplified _esaS 、P _esaR The primers of the gene are P with nucleotide sequences shown as SEQ ID NO.15, SEQ ID NO.16, SEQ ID NO.17 and SEQ ID NO.18 respectively _esaS -F、P _esaS -R、P _esaR -F、P _esaR -R。

7. The method of claim 4, wherein in the step (1), primers for amplifying mCherry and EGFP genes are mCherry-F, mCherry-R, EGFP-F, EGFP-R with the nucleotide sequences shown in SEQ ID NO.19, SEQ ID NO.20, SEQ ID NO.21 and SEQ ID NO.22, respectively.

8. The use of the genetically engineered Escherichia coli of any one of claims 1 to 3 in the production of xylanase.

9. The application of claim 8, wherein the xylanase is produced by replacing xylanase gene with xylanase gene shown in SEQ ID NO.23, and inoculating the strain to fermentation medium.

10. The use of claim 9, wherein the fermentation medium comprises 30g/L glucose, 0.8g/L sodium chloride, 20-22g/L ammonium sulfate, 2g/L anhydrous potassium dihydrogen phosphate, 0.8g/L magnesium sulfate heptahydrate, 0.02g/L manganese sulfate pentahydrate, 0.02g/L iron sulfate heptahydrate, 10.002g/L vitamin B, 1g/L yeast powder and 15-30g/L calcium carbonate.