35 results about "Coli cell" patented technology

The invention belongs to the technical field of bioengineering, and discloses a plasma membrane localized green fluorescence overexpression vector as well as a construction method and application thereof. The cytoplasmic membrane localized green fluorescence overexpression vector contains an expression vector skeleton and an AtCBL1 gene connected to the expression vector skeleton, wherein the nucleotide sequence of the AtCBL1 gene is shown as SEQIDNO: 1, and the expression vector skeleton also carries a fluorescent protein gene. The construction method of the vector comprises the following steps: S1, carrying out enzyme digestion and recovery on an AtCBL1 gene sequence with a nucleotide sequence as shown in SEQIDNO: 1 obtained by amplification; s2, performing same enzyme digestion on the expression vector carrying the fluorescent protein gene, and recovering; and S3, connecting the AtCBL1 gene subjected to enzyme digestion with the expression vector to form a recombinant plasmid, converting a connection product into an escherichia coli competent cell, and extracting the recombinant plasmid from positive clone to obtain the plasma membrane localized green fluorescence overexpression vector.

The present invention relates to a method for treatment of polyhydroxyalkanoate (PHA) containing post-consumer product, the method comprising contacting a post-consumer product with a polypeptide that can catalyze degradation of the PHA, the contact taking place at a temperature at least 45° C. In a specific embodiment, the poly peptide is a wild-type PHA depolymerase expressed by a thermophilic microorganism or a modified PHA depolymerase that includes one or more single-site mutations as compared to the wild-type PHA depolymerase. In another specific embodiment, the polypeptide comprising a modified poly hydroxy butyrate (PHB) depolymerase comprising one or more single-site mutations as compared to SEQ ID NO: 1, and the modified PHB depolymerase having an optimum temperature of at least 45° C. The present invention also relates to a host cell transformed to express a polypeptide that catalyzes degradation of a PHA, the polypeptide having an optimum temperature for the degradation reaction of at least 45° C., wherein the host cell is selected from an E. coli cell or a thermophilic microorganism.

The invention provides a measles virus nucleoprotein specific nano antibody as well as a preparation method and application thereof. The amino acid sequence of the nano antibody is any one of A1-A18; the rash virus nucleoprotein can be specifically recognized and combined. And the nano antibody can be massively expressed and purified in escherichia coli cells, so that a potential nano antibody drug with a great application prospect is provided for clinical prevention, treatment and detection of measles viruses.

The present application relates to the field of microorganisms and genetic engineering, and specifically discloses an Escherichia coli engineering bacterium for efficiently producing plastic depolymerase and application thereof. The present application uses Escherichia coli as a host, and through synergistic optimization of multiple key dimensions such as signal peptide, promoter, solubility-promoting tag and co-expression of molecular chaperones, a multi-dimensional engineering system for efficiently expressing plastic depolymerase is constructed. The construction method provided by the present application includes a rational design and a screening strategy for combination and assembly of the multiple elements. The engineering bacterium can realize extracellular high-level expression of plastic depolymerase during induced fermentation, and the enzyme preparation prepared can be directly used for catalyzing efficient depolymerization of polyester plastics. The present application provides an Escherichia coli cell factory with stable high yield for industrialization and low-cost production of plastic depolymerase, and has important industrial application prospects for promoting large-scale biological degradation and resource recycling of waste plastics.

This invention discloses a directed evolution strategy for SsDMS, a type II sesquiterpene cyclase derived from *Streptomyces showdoensis*, based on alanine scanning, and its applications. The invention describes several key mutant sites in SsDMS capable of catalyzing the generation of novel dried sesquiterpene compounds, including substitutions at positions 208, 248, 249, 497, and 505. This invention also discloses a highly efficient *E. coli* cell factory applied to the heterologous expression of SsDMS mutants and the efficient production of novel dried sesquiterpene compounds, further yielding structurally novel dried sesquiterpene compounds. This invention achieves the efficient production of dried sesquiterpene compounds using SsDMS and its mutants. Its modification strategy has broad applicability, providing important enzymatic resources for the biosynthesis of novel terpenoids and offering more options for the discovery of drug lead compounds.

The invention provides a method for extracting and purifying CRM197 protein, and belongs to the technical field of vaccine preparation. Specifically, CRM197 protein is expressed in escherichia coli cytoplasm by adopting a method without adding signal peptide and fusion tag, thalli are treated by an osmotic pressure method (repeated freezing and thawing + hypertonic solution + hypotonic solution) so as to extract soluble expression CRM197 protein in cytoplasm, and then two-step column chromatography (anion column chromatography + hydrophobic column chromatography) is carried out to obtain the CRM197 protein in the cytoplasm. The target protein with relatively high purity is obtained. The CRM197 protein extraction and purification method provided by the invention is simple, efficient and easy to operate, does not need the assistance of complex equipment, and has a cost advantage.

The invention belongs to the technical field of synthetic biology and biological materials, and particularly relates to a cellulose synthetase high-efficiency expression system based on a cell membrane adaptation strategy, and a preparation method and application of cellulose microfibrils. The method is used for efficient heterologous expression of cellulose synthetase subunits PtCesA1 and PtCesA8 from populus trichocarpa, and in-vivo synthesis of cellulose microfibrils is realized. The key enzyme NMT of a phosphatidylcholine synthesis route is introduced to modify the escherichia coli cell membrane lipid composition, so that the expression efficiency and the cellulose synthesis capability of the eukaryotic-source membrane protein are remarkably improved. Further, the cellulose yield is remarkably increased by systematically optimizing culture conditions such as concentration, temperature and time of the inducer. The system constructed by the invention can be used for directly synthesizing cellulose microfibrils with an ordered structure and high purity in escherichia coli, and a new path is provided for green biological manufacturing of cellulose.

The invention relates to the technical field of biology, in particular to a Cas protein mutant, a fusion protein and application of the Cas protein mutant and the fusion protein in gene editing. The research finds that the Cas12h protease complex has the capability of specifically cutting a non-target chain (NTS) in double-stranded DNA in vitro, so that the open loop of the DNA double-stranded DNA is triggered. Based on the characteristic, the invention further develops a gene silencing function of Cas12h in vivo, and successfully realizes a silencing effect on transcription and expression of a specific gene in escherichia coli. Meanwhile, an adenine base editor based on Cas12h fusion protein is further developed, and accurate base conversion from A-T to G-C on the DNA level is successfully realized in escherichia coli cells by finely regulating and controlling growth conditions of the base editor, optimizing peptide connector design and reasonably constructing a fusion protein structure.

This invention relates to a quantitative method for ultrasonic disruption of *E. coli* cells, specifically a method based on firefly luciferase in *E. coli* cells. The method involves mixing *E. coli* expressing firefly luciferase as an internal standard with a suspension of target protein-expressing bacteria, followed by ultrasonic disruption of the cells. The degree of disruption of the target protein-expressing bacterial suspension is quantitatively calculated by measuring the activity of the firefly luciferase. The target protein-expressing bacterial suspension uses *E. coli* expressing the target protein. Compared with existing technologies, this invention overcomes the shortcomings of complex experiments, low efficiency, and unstable accuracy in existing technologies. It achieves efficient and highly accurate quantification of the degree of ultrasonic disruption of *E. coli* cells, reduces experimental complexity, and improves research and development efficiency and accuracy. This provides a scientific basis and new approach for the development of new feed protein resources and livestock breeding research, and has broad application potential.

The application discloses a kind of recombinant escherichia coli for producing NMN and its preparation method and application, belong to genetic engineering and bioengineering technical field.The application expresses nicotinamide phosphoric acid ribosyltransferase NAMPT as shown in SEQ ID NO.1 in escherichia coli, expresses PRPP synthetase BaPRS as shown in SEQ ID NO.2, expresses transporter BMpnuC as shown in SEQ ID NO.3, and knocks out pncC gene, ushA gene, nadR gene and purR gene, improves the accumulation amount of NMN in escherichia coli cell.The application also optimizes fermentation condition, so that NMN can be accumulated efficiently outside cell, and more than 20g / L NMN can be obtained in 5L fermentation system, and has wide application prospect in the field of medicine, cosmetics, feed, textile and the like.

The invention relates to the field of whole-cell biosensors, and provides a whole-cell biosensor array and an early warning model for monitoring the mildewing degree and aflatoxin content of corn peanuts. The Escherichia coli cell comprises a promoter related to the response of a volatile organic compound released by Aspergillus flavus pollution, the promoter is operably connected with a reporter gene, and an expression product of the reporter gene is used for generating a bioluminescence signal which can be detected. Through the whole-cell biosensor and the array thereof, related volatile organic compounds after corn peanuts are infected by aspergillus flavus can be accurately responded, so that rapid and high-sensitivity monitoring on aspergillus flavus mildew and toxin pollution is realized. Besides, the whole-cell biosensor array is combined with a machine learning regression model, so that the aspergillus flavus infection degree can be quantified, and the aflatoxin content can be predicted.

The invention discloses a construction method of escherichia coli for efficiently synthesizing glycollic acid, and belongs to the technical field of biochemical engineering. According to the invention, citric acid synthase gltA and aconitic acid synthase acnA and acnB are overexpressed in escherichia coli cells, pyruvate dehydrogenase transcription inhibition factor pdhR is knocked out, transhydrogenase pntA and pntB are overexpressed, and transhydrogenase stA is knocked out, so that the constructed recombinant escherichia coli can produce glycollic acid by using glucose in a short time. The reaction cost is lower, the yield is higher, the concentration of glycollic acid produced after fermentation in a 5L fermentation tank for 48 hours is 81 g / L, the conversion rate is 0.62 g / g, and the production intensity is 1.69 g / L / h.

The application provides a method for extracting and purifying CRM197 protein, and belongs to the technical field of vaccine preparation. Specifically, the CRM197 protein is expressed in the cytoplasm of Escherichia coli by a method without signal peptide and fusion tag addition, and the bacterial cells are treated by an osmotic pressure method (repeated freeze-thawing + high-osmotic solution + low-osmotic solution) to extract the CRM197 protein expressed in the cytoplasm, and then two-step column chromatography (anion column chromatography + hydrophobic column chromatography) is performed to obtain the target protein with high purity. The method for extracting and purifying the CRM197 protein is simple, efficient, easy to operate, does not need complex equipment assistance, and has a cost advantage.

The invention provides quantum dot modified group B neisseria meningitidis and a preparation method of a vaccine of the quantum dot modified group B neisseria meningitidis. The preparation method comprises the following steps: taking corn straws and sunflower straws as a straw mixture according to a weight ratio of (1-1.5): 1, putting the straw mixture, an escherichia coli DH5alpha cell membrane and urea into water according to a weight ratio of 100: 100: 1, carrying out high-temperature heating reaction, and filtering and dialyzing reactants to prepare aminated quantum dots; extruding the aminated quantum dots and a group B neisseria meningitidis cell membrane through a liposome extruder according to a weight ratio of (8-10): 1, and centrifuging to obtain cell membrane hybrid aminated quantum dots; and co-incubating the cell membrane hybrid aminated quantum dots and the group B neisseria meningitidis to obtain the cell membrane hybrid aminated quantum dots. The group B neisseria meningitidis is modified by adopting the specific quantum dots, the toxicity of the modified group B neisseria meningitidis is obviously reduced, and the modified group B neisseria meningitidis is expected to be applied to related fields of vaccines and the like.

This invention relates to the field of genetic engineering technology, and particularly to TEV protease mutants, their preparation methods, and applications. This invention modifies the TEV enzyme molecule, with mutation points differing from those reported in previous studies. This enhances the activity of the TEV protease at the molecular level. Furthermore, this invention utilizes CRISPR / Cas9 gene editing techniques to modify the host bacterial chassis, obtaining engineered strains that express TEV at high yields. Further, the provided high-density fermentation control method can rapidly promote TEV enzyme expression, resulting in high E. coli cell yield, with an OD600 value reaching approximately 150, a cell wet weight of 80–130 g / L, and high expression levels of the target protein, accounting for 40%–64% of the total bacterial protein. Simultaneously, the method provided by this invention is simple and easy to implement, using readily available raw materials, achieving good application results while reducing production costs, resulting in significant economic benefits.

The invention relates to an Escherichia coli (E. coli-BSO) biological compound system for biological hydrogen production. The biological composite system breaks through the limitation of a traditional single microorganism and material hydrogen production system, bismuth stannate (BSO) nanoparticles and escherichia coli are combined through electrostatic interaction, and a novel composite system with the microbial metabolism hydrogen production capacity and the nanometer material photocatalytic performance is constructed. The system creatively integrates the inherent hydrogen production metabolic pathway in escherichia coli cells and the excellent visible light absorption capacity and photocatalytic electron transfer performance of the BSO nano material, and solves the problems that the light energy utilization rate of pure microorganisms is low, and hydrogen production of pure photocatalytic materials depends on exogenous electron donors. Experiments prove that under visible light irradiation, the hydrogen yield of the composite system reaches 0.8 mmol within 4 hours, the hydrogen production efficiency is improved by 1.5 times compared with that of pure escherichia coli, and the efficiency bottleneck of an existing biological hydrogen production technology is remarkably broken through.

This invention discloses a β-lactoglobulin mutant, its preparation method, and its application, relating to the field of genetic engineering technology. The amino acid sequence of the β-lactoglobulin mutant is shown in SEQ ID NO.1. The preparation method is as follows: designing forward primers, reverse primers, forward mutation primers, and reverse mutation primers; using wild-type β-Lg plasmid as a template, obtaining a mutant DNA fragment using overlap extension PCR technology; ligating the mutant DNA fragment into an empty vector and transforming it into competent E. coli cells for culture and identification to obtain a recombinant plasmid; transforming the recombinant plasmid into competent E. coli cells, culturing, lysing, collecting the cell supernatant, purifying, and obtaining the β-lactoglobulin mutant. This invention, through structural modification of β-lactoglobulin, improves its binding to specific IgE antibodies, enhances the immunogenicity of β-lactoglobulin allergens, and improves the sensitivity and specificity of its allergen-specific IgE antibody detection results.

The application prepares an E.coli-BSO biological composite system for biological hydrogen production. The biological composite system breaks through the limitation of traditional single microorganism and material hydrogen production system, combines bismuth stannate (BSO) nanoparticles and E.coli through electrostatic interaction, and constructs a new composite system with the hydrogen production ability of microbial metabolism and the photocatalytic performance of nanomaterials. The system integrates the inherent hydrogen production metabolic pathway in E.coli cells and the excellent visible light absorption ability and photocatalytic electron transfer performance of BSO nanomaterials, solves the problems of low light energy utilization rate of pure microorganisms and hydrogen production of pure photocatalytic materials depending on external electron donors. Experimental verification shows that under visible light irradiation, the hydrogen production of the composite system reaches 0.8 mmol within 4 hours, which is 1.5 times higher than that of pure E.coli, and significantly breaks through the efficiency bottleneck of existing biological hydrogen production technology.

The invention relates to the technical field of competent escherichia coli cell preparation, and discloses a preparation method of competent escherichia coli cells for gene transformation, which comprises the following steps: step 1, strain activation; step 2, strain amplification culture; step 3, low-temperature suspension and washing: transferring the bacterial liquid into a pre-cooling centrifugal tube, standing on ice, then centrifuging, discarding supernate, adding a pre-cooled CaCl2 solution, gently resuspending, placing on ice, and then centrifuging; step 4, preparation of a competent suspension: removing the supernatant, adding a precooled CaCl2 solution containing glycerol, slightly suspending thalli, and standing on ice for 3-5 minutes to prepare a competent cell suspension; the mass fraction of glycerol in the CaCl2 solution containing glycerol is 15%; the concentration of CaCl2 is 0.05 mol / L; and step 5, sub-packaging and cryopreservation: sub-packaging the obtained competent suspension, and cryopreserving at-80 DEG C. According to the scheme, by optimizing the concentration of CaCl2 and glycerol in the suspension, the suspension temperature and the like, the conversion efficiency, the storage period and the cell membrane stability are effectively improved.

The present disclosure describes a unique viral peptide (VP) vaccine for preventing or treating viral diseases. The vaccine is produced synthetically and includes no production steps in biological cells (e.g. E. coli, CHO cells, yeast cells) that would require subsequent endotoxin assays / removal or viral clearance procedures. The hC peptide is synthesized separately from the VP, and following self-assembly of the hC, the VP is covalently coupled to form the VP-hC conjugate which can serve as a vaccine for preventing or treating viral diseases. The hC includes heptad repeats following a specific pattern. Optionally, the VP-hC conjugate further includes one or more T-cell epitopes at the N- and / or C-terminus of the one or more amphipathic alpha-helices. The present disclosure also describes compositions comprising immunogenic compositions including VP-hC conjugate.

This invention provides a method for producing full-length antibodies in Escherichia coli at a yield of approximately 200 mg / L or more. [Solution] A method for producing a full-length antibody comprising a heavy chain (HC) and a light chain (LC), comprising culturing Escherichia coli cells expressing the coding sequence of the HC and the coding sequence of the LC in a culture medium under conditions acceptable for producing the HC and the LC, wherein the full-length antibody is produced in an amount of at least about 200 mg per liter of the culture medium, or the weight percentage of the produced full-length antibody relative to the weight of the cell pellet produced from the Escherichia coli cells is in the range of 0.05% to 20%.

The invention belongs to the technical field of gene engineering, and relates to a method for improving the expression efficiency of penicillin G acylase protein by modifying a signal peptide. According to the invention, E.coli BL21 (DE3) / pET28a-kcPGA is taken as an original strain, an Erwinia carotovora PelB amino terminal leader sequence (the signal peptide is named as pelB) is synthesized through oligonucleotide primer fusion PCR, then the pelB signal peptide is connected with a PGA gene segment without an original signal peptide by using a homologous recombination method, and finally a recombinant plasmid is constructed through seamless cloning, so that the Erwinia carotovora PelB gene fragment is obtained. And the penicillin G is transformed into escherichia coli cells, so that the expression efficiency of the penicillin G acylase is improved. Compared with original recombinant bacteria, the recombinant engineering strain constructed by the invention has the advantages that the protein expression quantity is greatly improved, the enzyme activity is also improved by about two times, the problem of low expression quantity of penicillin G acylase in escherichia coli cells is effectively solved, and the recombinant engineering strain has wider industrial production and application prospects.

The invention discloses a method for efficiently synthesizing succinic acid by improving cell biomass and cell viability through quorum sensing regulation and control. Through overexpression of ptsH, a normal quorum sensing system of Escherichia coli can be effectively destroyed, and an AI-2 signal channel is quenched. According to the method, the autolysis rate of escherichia coli can be reduced, and the cell biomass and the cell activity can be improved. Fermentation verifies that after ptsH is over-expressed, the high thallus amount level that OD600 is larger than 7 is maintained in the whole succinic acid fermentation process, the maximum OD600 is 8.5, and the final succinic acid yield is 80.12 g / L. Compared with escherichia coli without over-expression of ptsH, the maximum OD600 is improved by 30.7%, and the yield of succinic acid is improved by 17.9%. According to the method, the cell biomass and the cell activity in the fermentation process can be effectively improved, the succinic acid production capacity of the recombinant escherichia coli is remarkably enhanced, and the method has important application value.

The invention discloses a method for screening a melon cold-resistant gene based on a cDNA yeast library, and belongs to the field of gene engineering. The method comprises the following steps: sampling melon leaves subjected to low-temperature treatment, extracting total RNA (Ribonucleic Acid), carrying out reverse transcription to obtain a high-coverage-rate cDNA (Complementary Deoxyribonucleic Acid) library, connecting the cDNA library with a linker to form a three-frame library, connecting the cDNA library to a pYES-NTB carrier, electrically transforming the obtained cDNA library into an escherichia coli competent cell, carrying out cloning amplification, and extracting library plasmids; and transforming the library plasmid and the pYES2 vector into a yeast strain BY4741, screening at low temperature of-20 DEG C for 72 hours, collecting cold-resistant clones, and amplifying and sequencing to obtain the cold-resistant gene of the muskmelon. The constructed yeast system is utilized to efficiently identify potential candidate genes for improving the cold resistance of the muskmelon seedlings, and a foundation is laid for genetic engineering breeding of low-temperature stress resistance of muskmelons.

The invention provides a non-chromatography protein purification label and method suitable for a ship carbon capture biocatalyst-carbonic anhydrase. The method comprises the following steps: connecting a target protein with a purification tag through a proper connecting sequence-linker to construct a target protein-separation tag chimera, constructing the target protein-separation tag chimera in a proper escherichia coli expression vector, introducing the target protein-separation tag chimera into escherichia coli cells, carrying out conventional expansion and induction of strains, collecting bacterial liquid precipitate, and carrying out freeze-drying to obtain the target protein-separation tag chimera. The method comprises the following steps of: taking a crude enzyme as a raw material, resuspending the crude enzyme in a proper buffer solution, crushing at a certain power, collecting crude enzyme precipitate, resuspending the crude enzyme precipitate in the buffer solution, centrifuging at a low speed for 10 minutes, and discarding impurity supernatant, which is a round of purification process, and purifying for 2-3 rounds to obtain the target protein with higher purity.

The invention belongs to the technical field of bioengineering, and particularly relates to a PaSCLec gene with bacteriostatic activity and application of the PaSCLec gene, the nucleotide sequence of the PaSCLec gene is shown as SEQ ID NO.2, and the coded amino acid sequence is shown as SEQ ID NO.3. The invention further discloses a preparation method of the PaSCLec gene. The invention finds that a secretory C-type lectin PaSCLec of periplaneta americana is subjected to variable shearing after natural evolution, and a truncated variant appears. The antibacterial property of the C-type lectin is detected in multiple aspects through in-vitro expression and purification, and it is found that the C-type lectin partially gets rid of the limitation that the function of the C-type lectin needs to depend on Ca < 2 + >, can be directly combined with polysaccharide on the surface of bacteria and destroys the cell structure of escherichia coli, and in addition, the C-type lectin depends on Ca < 2 + > to agglutinate bacteria, so that the C-type lectin the cell structure of the staphylococcus aureus can also be destroyed. In-vitro researches on the protein find that the variant C-type agglutinin not only has the effects of binding, agglutinating and inhibiting bacteria, but also can destroy the cell structure of bacteria so as to kill the bacteria.

The invention discloses a recombinant expression vector and cell for producing bFGF and a production method, and relates to the technical field of biological protein production. According to the production method, a recombinant expression vector for highly expressing the bFGF is prepared by improvement on the basis of a pGEX-6P-1 commercial vector, escherichia coli cells are transformed by the recombinant expression vector to obtain recombinant escherichia coli cells, and then the high-yield and high-purity bFGF is obtained by utilizing the recombinant escherichia coli cells. The technical bottlenecks of low expression efficiency, complex purification process, high cost, poor vector adaptability and the like in the existing recombinant bFGF production are remarkably solved through promoter modification, fusion expression unit design and intein mutation optimization of an expression vector.

Described herein are engineered E. coli cells and strains comprising genetic modifications leading to enhanced efficiency of non-standard amino acid (nsAA) incorporation, and increased expression of nsAA-containing proteins, while preserving cellular viability and adequate growth properties. For example, described herein are engineered E. coli cells and strains in which the plasmid burden is reduced (e.g., wherein nucleic acids encoding an OTS, and / or other regulatory elements are genomically incorporated instead of being introduced on a plasmid). Also described herein are engineered E. coli cells and strains with RF1 gene knockout. In particular, described herein are E. coli RF1 knockout cells and strains which comprise an orthogonal translation system (OTS) and in which TAG codons of certain genes are recoded to TAA. Also described herein are methods of producing a target polypeptide or a target peptide comprising one or more nsAAs using the engineered E. coli cells and strains.

The invention relates to the field of microorganisms and genetic engineering, and particularly discloses an escherichia coli engineering bacterium for efficiently producing plastic depolymerases and application of the escherichia coli engineering bacterium. According to the invention, escherichia coli is taken as a host, and a multi-dimensional engineering system for efficiently expressing the plastic depolymerases is constructed by synergistically optimizing a plurality of key dimensions such as signal peptide, a promoter, a dissolution promoting tag and a co-expression molecular chaperone. The construction method provided by the invention comprises rational design of the plurality of elements and a screening strategy of combination and assembly. The engineering bacterium can realize extracellular high-level expression of the plastic depolymerization enzyme in the induced fermentation process, and the prepared enzyme preparation can be directly used for catalyzing efficient depolymerization of polyester plastics. The invention provides a stable and high-yield escherichia coli cell factory for industrial and low-cost production of the plastic depolymerases, and has important industrial application prospects for promoting large-scale biodegradation and resource circulation of waste plastics.

This invention relates to the field of biotechnology, specifically disclosing a cell-free protein expression system (CFS), its applications, and a kit. The CFS comprises: 35-50 vol% *E. coli* cell extract, 40-50 vol% lysis buffer, 8-12 vol% gene template, and 2-15 vol% nuclease-free water; wherein the *E. coli* is a recombinant bacterium obtained by modifying a recipient *E. coli*, the modification including: (1) knocking out the LacZ gene in the recipient *E. coli*; and (2) adding the LyseR gene to the recipient *E. coli*. The CFS of this invention features high expression activity and gene stability, making it suitable for expressing high molecular weight proteins and for in vitro diagnostic applications based on cell-free sensors.