1658 results about "Escherichia coli" patented technology

The invention relates to a construction method of escherichia coli engineering bacteria with high yield of N-acetylglucosamine. According to the method, the metabolic network of escherichia coli is directionally modified through metabolic engineering, the problems of'product re-decomposition ', by-product accumulation, poor genetic stability and the like of natural strains are solved, and efficient industrial production of GlcNAc is realized.

The invention relates to the technical field of synthetic biology, in particular to recombinant XVII type collagen as well as a preparation method and application thereof.The amino acid sequence of the recombinant XVII type collagen comprises a sequence shown in any one of SEQ ID NO.1-SEQ ID NO.3. The recombinant XVII type collagen can be highly expressed in an escherichia coli and pichia pastoris system, the expression system is simple, the cost is low, and the recombinant XVII type collagen is suitable for industrial production. The yield is high; the biological activity is good. The protein can be compounded with other proteins to form raw materials of tissue engineering products, cosmetics, health care products or medicines, so that the protein can be widely applied to the fields of medicines, medical instruments, biological materials, tissue engineering, cosmetics and the like.

The invention discloses SGNH family esterase SH2 screened in a Tibetan hot spring environment and application of the SGNH family esterase SH2, and belongs to the technical field of gene engineering. According to the invention, a new SGNH family esterase gene is screened from a Tibetan hot spring environment, and recombinant expression is realized in escherichia coli. The recombinant esterase prepared by the invention has the characteristics of thermal stability, salt resistance, organic solvent resistance and the like, can be safely applied to tooth whitening or skin exfoliating products, avoids damage of traditional chemical bleaching agents to enamel, and has important application value in the fields of daily chemicals, medicines, food processing and the like.

The invention provides a genetically engineered bacterium for producing O-succinyl-L-homoserine as well as a construction method and application of the genetically engineered bacterium. In a chassis bacterium genome, the expression of a 2-ketoglutaric acid decarboxylase encoding gene sucA is enhanced, and the expression of a succinyl-coenzyme A synthetase encoding gene sucD is weakened, so that the supply of succinyl-coenzyme A is increased; the method comprises the following steps: increasing the NADPH (Nicotinamide Adenine Dinucleotide Phosphate) reducing capacity and ATP (Adenosine Triphosphate) energy supply of a chassis bacterium, increasing DNA (Deoxyribose Nucleic Acid) in combination with a transcription dual regulatory factor ompR to improve the stress resistance of escherichia coli under high osmotic pressure, and introducing an overexpression plasmid containing a homoserine transsuccinylase coding gene metA to construct the genetically engineered bacterium for producing O-succinyl-L-homoserine. The engineering strain obtained through a systematic metabolic engineering modification strategy can realize effective accumulation of OSH, the shake flask yield of OSH reaches 19.8 g / L, the fed-batch fermentation yield of a 5L fermentation tank reaches 110.5 g / L, the sugar-acid conversion rate reaches 52.6%, and a foundation is laid for subsequent construction of high-yield OSH engineering bacteria.

The invention relates to the technical field of Escherichia coli drug resistance analysis, in particular to an Escherichia coli antibiotic drug resistance detection method based on SERS and machine learning. The invention provides an Escherichia coli antibiotic resistance detection method based on SERS (Surface Enhanced Raman Scattering) and machine learning so as to overcome the defect that high-precision and rapid diagnosis cannot be realized in the prior art. The invention aims to realize rapid and high-precision identification of drug-resistant bacteria through a machine learning algorithm by utilizing a core-shell nanostructure SERS substrate of silver-coated gold nanoparticles and combining SERS spectrum differences of drug-resistant escherichia coli with different phenotypes. Through the method, the detection time can be remarkably shortened, the detection precision can be improved, an accurate drug treatment scheme is provided for clinic, and the method has a wide application prospect.

The invention relates to an Escherichia coli engineering strain for producing 2, 3-pentanediol as well as a construction method and application of the Escherichia coli engineering strain, and the method comprises the following steps: constructing recombinant plasmids pACYC-IlvA *-ThrA * BC for expressing an IlvA * gene of threonine deaminase, a ThrA gene of asparaginic acid kinase I, a Thr B gene of homoserine kinase and a ThrC gene of threonine synthetase; the method comprises the following steps: constructing a recombinant plasmid pRSF-Ilv2C-Aro10 for expressing an Ilv2C gene of acetohydroxy acid synthetase and an Aro10 gene of propiophenone dehydrogenase; and chemically converting the recombinant plasmid pACYC-IlvA *-ThrA * BC and the recombinant plasmid pRSF-Ilv2C-Aro10, and transferring the recombinant plasmid pACYC-IlvA *-ThrA * BC and the recombinant plasmid pRSF-Ilv2C-Aro10 into escherichia coli so as to obtain the escherichia coli engineering strain for producing the 2, 3-pentanediol. According to the escherichia coli engineering strain, the biosynthesis of 1.61 g / L of 2, 3-pentanediol is realized by using L-threonine and 40 g / L of glucose.

The present application relates to the technical field of biocatalysis and biosynthesis, and specifically discloses a natural blue pigment and a biosynthesis method therefor. The present application uses metabolically engineered bacteria to express indigoidine synthetase and phosphopantetheinyl transferase, to catalyze glutamine and N-acetylglutamine to biosynthesize a natural blue pigment N-acetylindigoidine, and deduces its molecular structure by means of mass spectrometry, nuclear magnetic resonance and other methods. The present application achieves catalytic synthesis of N-acetylindigoidine from glutamine and N-acetylglutamine in Escherichia coli, Corynebacterium glutamicum, Saccharomyces cerevisiae and Streptomyces. Compared with indigoidine, N-acetylindigoidine has a maximum absorption wavelength of 584 nm, possesses better color brightness, and has more stable coloration that is not easily faded, with a very broad application range and industrial production application prospects.

The invention relates to epsilon-polylysine epsilon-PL-loaded modified rice bran protein antibacterial nanoparticles as well as a preparation method and application thereof, and belongs to the technical field of preparation of nanoparticles. The preparation method comprises the following steps: extracting rice bran protein from defatted rice bran to prepare a rice bran protein stock solution; under continuous stirring, adding succinic anhydride into the rice bran protein stock solution to obtain acylated rice bran protein; mixing the acylated rice bran protein stock solution, the lactose stock solution and the epsilon-PL stock solution; and centrifuging and freeze-drying to obtain the epsilon-PL-loaded modified rice bran protein antibacterial nanoparticles. The preparation method disclosed by the invention is simple and low in cost, the prepared nanoparticles have smaller particle size and turbidity and higher stability, the hygroscopicity of epsilon-PL can be reduced to a great extent, the bioavailability of epsilon-PL can be improved, and the nanoparticles have an obvious bacteriostatic effect on escherichia coli and staphylococcus aureus.

The invention discloses an Escherichia coli mutant strain which is classified and named as Escherichia coli, the strain number is CR-TK01, and the preservation number is CGMCC (China General Microbiological Culture Collection Center) No.35554. The invention further discloses a preparation method of the Escherichia coli mutant strain. The Escherichia coli CR-TK01 with high yield of cytidine provided by the invention has the characteristics of high yield and stable high-yield character, glucose is used as a carbon source, the Escherichia coli CR-TK01 is used for fermentation production of cytidine under a certain fermentation condition, and the yield of cytidine is as high as 97.23 g / L; the strain is not degraded after passage for more than 20 generations, the performance of high-yield cytidine is maintained in the passage fermentation process, and the yield of cytidine in passage fermentation is improved. The method for producing cytidine through fermentation is simple in process, high in yield and suitable for industrialization.

The invention provides a uracil production strain and a construction method and application thereof.According to the strain, on an E.coli UR14 genome by means of a CRIPSR / Cas9 gene editing technology, firstly, psuG genes, preTA genes, rutA genes and upp genes are knocked out, so that decomposition of uracil is blocked; then, a uridine phosphorylase gene udp and a pyrimidine-5 '-nucleotide nucleotidase gene ppnN are subjected to overexpression, and synthesis and accumulation of uracil are synergistically enhanced; and finally, overexpression of the ribose phosphate mutase gene pgm further enhances the conversion of a by-product ribose phosphate 1-precursor 5-ribose phosphate 1-pyrophosphate and improves the carbon utilization rate, and the obtained strain has good genetic stability and high fermentation yield, can stably produce uracil, and has wide application prospects.

The present application relates to the technical field of biocatalysis and biosynthesis, and specifically discloses a blue pigment and a biosynthesis method thereof. In the present application, an indigoidine synthetase and a 4′-phosphopantetheinyl transferase are expressed by a metabolically engineered strain to catalyze the biosynthesis of the blue pigment N-acetyl-indigoidine from glutamine and N-acetylglutamine, and a molecular structure of the blue pigment is inferred by mass spectrometry, nuclear magnetic resonance spectroscopy, etc. The present application achieves the catalytic synthesis of N-acetyl-indigoidine from glutamine and N-acetylglutamine in Escherichia coli (E. coli), Corynebacterium glutamicum (C. glutamicum), Saccharomyces cerevisiae (S. cerevisiae), and Streptomyces. Compared with indigoidine, N-acetyl-indigoidine has a maximum absorption wavelength of 584 nm, and a stable color having high brightness that is not easy to fade. Thus, the blue pigment shows an extensive application range and a promising industrial production prospect.

The invention belongs to the field of polypeptides, and particularly relates to an antibacterial peptide derived from marine microorganisms, an antibacterial composition and application. Based on a deep learning algorithm, five potential antibacterial peptides are mined from a global marine microbiome database, and the five antibacterial peptides are expressed in yarrowia lipolytica. Experimental tests show that the five antibacterial peptides have differentiated antibacterial effects on different bacteria, and the antibacterial peptide shown in SEQ ID NO: 3 can have an obvious inhibition effect on escherichia coli, pseudomonas aeruginosa and staphylococcus aureus, has low hemolysis and has a positive application prospect. The antibacterial peptide disclosed by the invention has the potential of further developing novel antibacterial drugs or antibacterial additives.

The invention relates to the technical field of gene engineering, in particular to Escherichia coli for efficient soluble expression of recombinant human collagen III and construction and application thereof. The invention constructs Escherichia coli for efficient soluble expression of recombinant human III type collagen, and the Escherichia coli can co-express the recombinant human III type collagen and molecular chaperone which are regulated and expressed by signal peptide. Experiments prove that the engineering bacterium provided by the invention has the capability of efficient soluble expression of the recombinant human III-type collagen, and the recombinant human III-type collagen provided by the invention has good stability and anti-inflammatory effect.

The invention provides a method for producing glycosyltransferase or sucrose synthase by fermenting recombinant escherichia coli, and belongs to the technical field of biological fermentation. According to the fermentation method provided by the invention, a three-stage material supplementing control fermentation strategy is adopted, namely after fermentation is carried out for 5 hours, material supplementing operation is started, the material supplementing speed is 6.24-7.20 g / L / h, fermentation is carried out for 8-10 hours, the material supplementing speed is reduced to 4.80 g / L / h, the temperature is reduced to 25 DEG C, and induction is carried out; then maintaining the material supplementing speed until the fermentation OD600 is 65-75, and then reducing the material supplementing speed to 3.84-4.80 g / L / h until the OD600 is not obviously increased any more; the material supplementing mode has remarkable advantages in the aspects of improving fermentation OD600 and fermentation enzyme activity, shortening the fermentation period, reducing the cost and the like.

The invention belongs to the technical field of microorganisms, and particularly relates to recombinant escherichia coli containing a PDRN sequence and a preparation method thereof, and the preparation method comprises the following steps: S1, preparing a PDRN solution; s2, complementing the double strands of the PDRN into blunt ends; s3, constructing a recombinant plasmid; s4, carrying out mixed culture on a product obtained in the step S3 and escherichia coli DH5alpha; s5, screening the recombinants; s6, carrying out PCR (Polymerase Chain Reaction) amplification, and recording a strain from a fragment with the length of more than 200bp; s7, preparing a seed solution by adopting the strain prepared in the step S6; s8, strain fermentation; and S9, centrifugally collecting thalli. The method comprises the following steps: constructing a recombinant plasmid containing a PDRN fragment, introducing the recombinant plasmid into Escherichia coli, subsequently culturing the recombinant Escherichia coli to copy DNA in the Escherichia coli, extracting a purified exogenous gene fragment to obtain a strain containing a single fragment PDRN sequence, and getting rid of dependence on raw materials during subsequent extraction.

The invention belongs to the technical field of biosynthesis, and particularly relates to an engineering bacterium for preparing stevioside through de novo fermentation as well as a preparation method and application of the engineering bacterium. According to the invention, mevalonate kinase in the MVA pathway is mutated and optimized. The method comprises the following steps: carrying out point mutation on mevalonate kinase MvK of a wild type source, constructing a stevioside synthesis route in an escherichia coli host, and comparing the influence of MvK mutation on the yield of stevioside, so as to determine a Q160L mutant, and applying the Q160L mutant to the stevioside production route to realize efficient production of stevioside.

The invention relates to the technical field of synthetic biology and microbial engineering, in particular to recombinant escherichia coli for de novo synthesis of forsythiaside A. The invention provides recombinant escherichia coli for de novo synthesis of forsythiaside A. A preparation method of the recombinant escherichia coli comprises a step of improving an escherichia coli starting strain, and the escherichia coli starting strain is escherichia coli MG1655. In the fermentation process of the recombinant escherichia coli, effective accumulation of forsythiaside A in fermentation liquor can be achieved, and a foundation can be laid for subsequent construction of high-yield forsythiaside A engineering bacteria.

The invention belongs to the technical field of synthetic biology, and particularly relates to recombinant escherichia coli for efficiently producing O-acetyl-L-homoserine as well as a construction method and application of the recombinant escherichia coli. According to the invention, CRISPR-Cas9 gene editing is combined with metabolic modification, so as to precisely integrate OAH biosynthesis key nodes: introducing and overexpressing a mutant metX gene at a genome pseudogene site to enhance the expression of homoserine acetyltransferase, knocking out byproducts such as poxB and mgsA to synthesize genes, and carrying out high-yield synthesis of OAH. Corynebacterium glutamicum thrA (anti-feedback inhibition), aspB and bacillus subtilis acsA-acuA genes (construction of an acetic acid switch) are introduced, gene expression of gltA, tpiA and the like is optimized to increase supply of precursors such as acetyl CoA and the like, and finally a stable strain without plasmids, antibiotics and inducers is obtained. The production cost is effectively reduced, and the method has the advantage of high genetic stability and shows a good application prospect in OAH industrial production.

The invention relates to a Paenibacillus polymyxa strain B01 and application of the Paenibacillus polymyxa strain B01, and belongs to the technical field of microorganisms. The paenibacillus polymyxa B01 disclosed by the invention is preserved in the Guangdong Microbial Culture Collection Center, and the preservation number of the paenibacillus polymyxa B01 is GDMCC NO.66594. The strain is obtained by separation, purification and screening from a soil sample, and tests show that the strain has excellent pH and high temperature tolerance; antibacterial active substances generated by fermentation of the bacillus subtilis have a relatively good antibacterial effect on escherichia coli, pseudomonas aeruginosa, pseudomonas putida, staphylococcus aureus, candida albicans, aspergillus brazilis, propionibacterium acnes and malassezia; and the antibacterial active substance has excellent heat resistance, cold resistance, illumination stability, pH stability and preservative effect, belongs to a mild low-irritation raw material, can be used for preparing daily chemical products and medicines, and has wide application prospects and important conversion research values.

The invention relates to the technical field of agricultural biology, in particular to a fusion P450 enzyme mutant, a method for improving VD3 catalytic activity and a method for generating 25 (OH) VD3 through whole cells. The invention constructs a fusion P450 enzyme VK1-CYP116B46-L21 and a self-sufficiency fusion P450 enzyme mutant with improved activity, wherein the self-sufficiency fusion P450 enzyme mutant is used for catalyzing vitamin D3 to synthesize calcifediol; vD3 is taken as a substrate, glucose, a cosolvent and a wet thallus induced by recombinant escherichia coli for simultaneously expressing fusion P450 enzyme and glucose dehydrogenase are added, and the highest yield of 25 (OH) VD3 within 24 hours after catalytic reaction can reach 3.26 g / L; whole cells are directly used as a catalyst, enzyme purification is not needed, glucose dehydrogenase is introduced, and glucose is used as a substrate to regenerate a cofactor NAD (P) H, so that addition of expensive cofactors is avoided, the production cost is reduced, and industrial production is facilitated.

The invention discloses a method for producing mRNA (messenger ribonucleic acid) template plasmids by fermenting escherichia coli. When the recombinant escherichia coli is fermented and cultured, a seed solution of the recombinant escherichia coli is inoculated into a basic culture medium to be fermented and cultured until the OD600 value of fermentation liquor is 18-22, then a fed-batch culture medium is continuously added at the feeding rate of 5-15 mL / L / h to be subjected to continuous fed-batch fermentation culture, the basic culture medium contains 0.05-0.2 mmoL / L of ferric salt compound and 0.05-0.2 mmoL / L of copper chloride dihydrate, and the basic culture medium contains 0.05-0.2 mmoL / L of ferric salt compound and 0.05-0.2 mmoL / L of copper chloride dihydrate. The basal culture medium contains 10-15 g / L of copper chloride dihydrate and 100-300 mg / L of p-hydroxybenzoic acid, the carbon source of the basal culture medium contains 0.1-0.3 mmoL / L of a ferric salt compound, 0.1-0.3 mmoL / L of copper chloride dihydrate and 100-300 mg / L of p-hydroxybenzoic acid, the carbon source of the fed-batch culture medium contains 360-480 g / L of glycerol, and the ferric salt compound is one or more of ferrous citrate, ferric ammonium citrate or ferrous sulfate heptahydrate. According to the method, the yield and superhelix content of the mRNA template plasmids are improved by optimizing the culture medium formula and culture conditions, and large-scale production of the high-quality target mRNA template plasmids is facilitated.

The invention relates to recombinant escherichia coli for de novo synthesis of piceatannol as well as a construction method and application thereof, and belongs to the field of synthetic biology and metabolic engineering. According to the invention, an L-tyrosine production strain is used as an original strain, five key genes required for synthesizing piceatannol are combined and connected to a plasmid vector, and a recombinant plasmid is introduced into the original strain, so that an engineering strain for heterologous synthesis of piceatannol is successfully constructed. According to the invention, the yield of piceatannol is further obviously improved through copy number optimization.

The invention discloses a progesterone 5beta-reductase mutant and application thereof in synthesis of 5beta-dihydrosteroid, relates to the technical field of biology, and in particular relates to application of gene mining and engineering modification of progesterone 5beta-reductase derived from bacteria in asymmetric synthesis of 5beta-dihydrosteroid. According to the progesterone 5 beta-reductase LpP5beta R disclosed by the invention, the progesterone 5 beta-reductase LpP5beta R from bacteria psoromais is obtained by a gene mining method, and the progesterone 5 beta-reductase LpP5beta R can be subjected to soluble expression in escherichia coli. The mutant obtained by mutating the wild type LpP5beta R has obviously improved catalytic ability on progesterone, and can efficiently catalyze delta 4-3-carbonyl steroids such as hydrocortisone, dinorcitol and the like to generate corresponding 5beta-dihydrosteroids. According to the invention, the technical bottlenecks of poor heterologous expression and low catalytic efficiency of plant-derived progesterone 5beta-reductase are solved, and a potential biocatalyst is provided for green manufacturing of 5beta-dihydrosteroid drugs.

The invention discloses a bacteriophage lyase and application thereof, and particularly relates to a bacteriophage lyase with an amino acid sequence as shown in SEQ INNO.2. The bacteriophage lyase can inhibit the growth of escherichia coli, staphylococcus and salmonella, can be used as an antibacterial substance in splitting gram-negative bacteria and can be used for preparing drugs for resisting gram-negative bacteria. The lyase can be used independently or compounded with other substances, the use concentration of antibiotics can be reduced by combining the lyase with the antibiotics, toxic and side effects (such as renal toxicity of polymyxin) of drugs are reduced, and meanwhile, generation of bacterial drug resistance is delayed. After the lyase and the chitosan are combined for use, remarkable antibacterial activity is generated, the antibacterial effect can be achieved without pre-treatment on bacteria, and the practicability is improved.

The invention discloses an expression system suitable for short-chain non-specific peroxidase and application of the expression system, and belongs to the technical field of enzyme engineering and genetic engineering. According to the expression system disclosed by the invention, a nucleotide sequence of short-chain non-specific peroxidase with SUMO and 8HIS tags is connected to a pET28a vector to obtain a recombinant vector, and escherichia coli BL21 (DE3) is transformed to obtain a genetically engineered bacterium; genetically engineered bacteria are subjected to two-stage temperature control culture in a ZYM5052 liquid culture medium, and meanwhile, 5ALA is added into the culture medium. According to the invention, an escherichia coli self-induction system is used, so that a shake-flask culture can grow at high density in a short time, the culture medium contains rich nutrient substances, and monitoring of cell density and adding of IPTG are not needed in the expression process. Meanwhile, a heme precursor 5ALA is added into an escherichia coli self-induction culture medium, and finally the high-activity short-chain non-specific peroxidase is obtained.

The invention discloses recombinant escherichia coli capable of producing salidroside and application, exogenous genes are introduced by utilizing a CRISPR / Cas9 technology, the recombinant escherichia coli capable of improving the fermentation yield of the salidroside is obtained by modifying and screening key genes, and finally, the salidroside is obtained by optimizing a fermentation tank process. The recombinant Escherichia coli can reach the highest yield of salidroside produced by fermentation of the scale at present on a 5L fermentation tank. The salidroside is fermented in a 5L fermentation tank for 104 hours, so that the maximum accumulation amount of the salidroside is 33.68 g / L, and industrial enlarged production is facilitated.

The invention relates to an alcohol oxidase mutant and application thereof. Specifically disclosed are a mutant derived from Gloeophyllum trabeum alcohol oxidase (GtrAOX-M2), a nucleic acid encoding the alcohol oxidase mutant, a recombinant expression vector containing the nucleic acid, a recombinant expression transformant containing the recombinant expression vector, a preparation method of a recombinant alcohol oxidase catalyst, and a preparation method of the recombinant alcohol oxidase catalyst. The invention also discloses a method for catalyzing methanol to be oxidized into formaldehyde by using the alcohol oxidase, the alcohol oxidase mutant or the recombinant alcohol oxidase catalyst. The activity of the alcohol oxidase mutant provided by the invention is obviously improved compared with that of a female parent, and the enzyme is high in activity and can be heterologously expressed in escherichia coli, so that the alcohol oxidase mutant can efficiently oxidize methanol into formaldehyde and oxidize the methanol into formaldehyde by a one-carbon unit biological utilization methanol enzyme method; wide application prospects are shown in the aspect of subsequent conversion and generation of polyhydric alcohols.

The invention provides a strain for producing L-isoleucine as well as a construction method and application thereof. The strain is obtained by modifying a chassis strain escherichia coli XX12 by utilizing a metabolic engineering modification method, ldhA, adhE and pflB genes are deleted, the transcriptional levels of aspC, pykF, pntAB, ppK, ppc, ilvAfbr, ilvIHfbr and ygaZH genes are up-regulated, the transcriptional level of a leuA gene is down-regulated, a bcd gene derived from B.subtilis 168 and ppnK and cysK genes derived from Cornebacterium glutamicum ATCC 13032 are heterologously expressed, and the strain has the advantages that the strain can be used for producing L-isoleucine; the method has the advantages of no need of adding resistant substances, good L-isoleucine synthesis capability, short fermentation period by using glucose as a carbon source, and good economic benefit and industrial application value.

The invention discloses an escherichia coli engineering bacterium for producing 5-ALA by an anaerobic fermentation method as well as a construction method and a fermentation method of the escherichia coli engineering bacterium. The engineering bacterium is constructed by taking escherichia coli (E. coli) ZX11 as a host and performing heterologous expression on 5-ALA synthetase (HemA) from rhodobacter capsulatus. In order to improve the soluble expression level of the HemA, the HemA is subjected to fusion expression with a maltose binding protein (MBP) tag. Furthermore, the engineering bacterium can also heterologously express a visual purple protein (PR) fused with the MBP tag. The construction method of the engineering bacteria comprises the following steps: sequentially cloning the MBP-HemA fusion gene and the PR gene to an expression vector and transferring into host bacteria. By utilizing the engineering bacteria provided by the invention, anaerobic fermentation can be carried out in a culture medium taking glucose as a carbon source, and 5-ALA can be efficiently synthesized. The invention provides an effective way for realizing green and energy-saving anaerobic biological manufacturing of 5-ALA.

The invention discloses a recombinant escherichia coli engineering strain for producing levodopa and application, and belongs to the technical field of genetic engineering and bioengineering. Escherichia coli WSH-Z06 is used as a starting strain, a levodopa synthesis route is constructed, and supply of cofactors is enhanced by introducing glucose dehydrogenase BmgdH; and the catalytic efficiency of the HpaB is greatly improved by modifying the entrance of the HpaB substrate tunnel. In addition, by optimizing the fermentation pH and induction time, the accumulation amount of the levodopa in the fermentation liquor reaches 60.7 g / L, the production intensity reaches 1.26 g / L / h, a foundation is laid for industrial production of the levodopa, and potential value and significance are achieved for development of synthetic biology.