326 results about "E coli bacteria" patented technology

The invention provides copper-loaded duck-origin lactobacillus plantarum with high antibacterial peptide yield and application of the copper-loaded duck-origin lactobacillus plantarum. The preservation number of the provided copper-loaded duck-origin lactobacillus plantarum is CGMCC (China General Microbiological Culture Collection Center) NO.32835. The domesticated and bred duck-origin lactobacillus plantarum with high antibacterial peptide yield can tolerate high-concentration copper ions, the domesticated and bred lactobacillus plantarum can stably grow, and the contents of antibacterial peptide, extracellular protein, lipase, amylase, lactic acid, acetic acid and the like in the domesticated and bred lactobacillus plantarum strain are increased; and the amino acid composition is changed. The strain can convert inorganic copper into organic copper, the utilization rate of copper is increased, and growth and development of organisms are promoted. Moreover, small peptides and extracellular proteins in metabiotics generated after fermentation have the effect of effectively inhibiting harmful bacteria such as riemerella anatipestifer, escherichia coli, salmonella and staphylococcus of poultry, and are beneficial to eliminating intestinal inflammatory factors, maintaining intestinal health and improving the feed utilization rate.

The invention relates to the technical field of gene engineering, in particular to an L-rhamnose isomerase mutant, a recombinant plasmid, a mutant strain and application. The amino acid sequence of the mutant is as shown in SEQ ID NO.4, and the nucleotide sequence of the coding gene is as shown in SEQ ID NO.3. A specific mutant gene sequence is designed, a recombinant plasmid pET28a (+)-L-Rhi is successfully constructed, the gene sequence is connected between enzyme cutting sites BamH I and Hind III of an escherichia coli expression vector pET-28a (+) to construct a mutant expression vector (the recombinant plasmid pET-28a (+)-L-Rhi), the mutant expression vector is transformed into an escherichia coli BL21 competent cell, a mutant strain is obtained, and the recombinant plasmid pET-28a (+)-L-Rhi is obtained. The obtained mutant strain can overexpress L-rhamnose isomerase, the conversion rate of D-allose is remarkably improved, the thermal stability of the enzyme is remarkably improved through the design of mutation sites, and the half-life period is effectively prolonged.

The present invention belongs to the field of genetic engineering technology and discloses a plasmid-free genetically engineered bacterium that can efficiently synthesize γ-aminobutyric acid from scratch using a cheap carbon source as a substrate, a method and an application thereof. The engineered bacterium is based on wild-type E. coli MG1655, overexpresses the T7 RNA polymerase gene; deletes the genes gabT and puuE; overexpresses gadC and gad bm , gdh, gltA, pyc, and ppc genes; and a growth-coupled promoter was used to dynamically regulate the expression of the sucA and argA genes in the GABA production pathway in Escherichia coli. All genetic manipulations in this engineered bacterium were performed within the genome, leaving no plasmid residues and requiring no antibiotics or inducers. The resulting strain exhibited stable production performance and a simple fermentation process. Using the engineered bacterium under a staged pH control process for 38 hours, the yield of γ-aminobutyric acid reached 35.4 g / L, demonstrating promising industrial application potential.

The invention relates to a preparation method and application of recombinant canine lactoferrin and peptide thereof, aiming at codon preference of host cells, canine lactoferrin genes are optimized, the full length of canine lactoferrin and the lactoferrin peptide are successfully expressed by virtue of an escherichia coli expression system, and the recombinant canine lactoferrin and the peptide thereof are identified by virtue of a minimum inhibitory concentration experiment. It is proved that the canine lactoferrin and the peptide thereof have the inhibiting capacity on pathogenic bacteria such as staphylococcus aureus, salmonella typhimurium and staphylococcus pseudointermedius, and the antibacterial activity MIC of the canine lactoferrin on the staphylococcus aureus, the salmonella typhimurium and the staphylococcus pseudointermedius is 1.5 mg / mL; the antibacterial activity MIC of the dog lactoferrin peptide to staphylococcus aureus is equal to 0.75 mg / mL, and the dog lactoferrin peptide shows high antibacterial ability.

Escherichia coli is modified by means of metabolic engineering, a genetically engineered bacterium for high yield of O-succinyl-L-homoserine is obtained, and a construction method of the genetically engineered bacterium comprises the following steps: weakening a synthetic route of an organic acid metabolic byproduct of a chassis strain E.coli W3110 [delta] metI [delta] metJ [delta] thrB [delta] metB; wherein the synthetic route of the organic acid metabolic byproducts is selected from at least one of a formic acid synthetic route, a lactic acid synthetic route and an ethanol synthetic route. The constructed genetically engineered bacterium is applied to microbial fermentation production of the O-succinyl-L-homoserine, effective accumulation of the O-succinyl-L-homoserine is achieved, the sugar acid conversion rate reaches 46.8%, and a foundation is laid for subsequent construction of high-yield O-succinyl-L-homoserine engineering bacteria.

The invention belongs to the field of metabolic engineering, and discloses a genetically engineered bacterium for producing myo-inositol as well as a construction method and application of the genetically engineered bacterium. The genetically engineered bacterium takes escherichia coli as an original strain, and is obtained by performing the following gene editing on a genome of the escherichia coli: non-expressed lactose operon repressor protein, glucose phosphate dehydrogenase, acetokinase, glucose phosphate isomerase and glycerol repressor protein; and overexpressing inositol-1-phosphate synthase, inositol monophosphate, glucokinase, glucose permease and glycerol kinase. Compared with the prior art, the genetically engineered bacterium disclosed by the invention has remarkable advantages in the aspects of key enzyme expression rate, metabolism specificity, fermentation period and the like, and an efficient, stable, economical and feasible solution is provided for industrial production of myo-inositol.

Compositions comprising 5. salivarius strain SALI-10 and / or salivarius 10 peptide are taught. Also taught are methods of treating bacterial infections comprising administering a pharmaceutically acceptable amount of the composition to the patient with a bacterial infection caused by a pathogen from, for example, multi-drug resistant (MDR) Streptococcus pneumoniae, Streptococcus pyogenes, Streptococcus dysagalactiae, vancomycin-resistant Enterococcus faecium, Porphyromonas gingivalis, Tannerella forsythia, and MDR Enterococcus faecalis.

The invention discloses an S-type three-dimensional carbon nitride / copper sulfide nanosphere heterojunction as well as a preparation method and application thereof, and belongs to the field of antibacterial application of nano materials. The three-dimensional porous carbon nitride not only can increase photocatalytic active sites, but also can improve close contact with copper sulfide. The copper sulfide nanospheres and the three-dimensional porous nanosheets construct an S-shaped heterojunction, and efficient separation of photo-induced electrons and hole pairs can be driven under the action of a built-in electric field, band edge bending and coulomb force. The S-type three-dimensional carbon nitride / copper sulfide nanosphere heterojunction can generate more active oxygen species to inactivate bacteria through a photocatalysis-Fenton-like reaction; in addition, the photothermal effect of copper sulphide has a certain auxiliary sterilization effect. Under the conditions of visible light irradiation and trace hydrogen peroxide, the inactivation rates of the S-type three-dimensional carbon nitride / copper sulfide nanosphere heterojunction on staphylococcus aureus and escherichia coli are up to 99.5% and 99.7% respectively, and meanwhile, the S-type three-dimensional carbon nitride / copper sulfide nanosphere heterojunction has a remarkable treatment effect on wounds infected by staphylococcus aureus.

The invention relates to the technical field of biology, in particular to a recombinant strain for producing glucuronic acid and application of the recombinant strain. The invention provides a recombinant strain for producing glucuronic acid, and the recombinant strain does not express uronic acid isomerase and overexpresses inositol oxidase. The technical scheme of the invention has the following advantages: (1) uronic acid isomerase uxaC from escherichia coli K12 is knocked out, so that glucuronic acid accumulation is increased; and (2) successfully integrating the target gene of the inositol oxidase from the mouse into the escherichia coli K12MG1655. And (3) when the engineering strain is used for catalyzing inositol, the content of glucuronic acid in a system after the reaction is finished is 52.50 g / L, and the conversion rate is as high as 97.23%.

The invention discloses a preparation method and application of a cat main allergen FEL-1 nano antibody FEL-1-Nb, and relates to the technical field of antibody preparation, and the preparation method comprises the following steps: preparing an immunogen; animal immunization and library construction; constructing and panning a phage display library; screening and identifying positive clone; and expression and purification of the nano antibody: cloning the positively cloned VHH gene to an expression vector such as a pET series, transforming an expression strain such as escherichia coli BL21 (DE3), carrying out IPTG induced expression, and purifying through an inclusion body purification method to obtain a high-purity nano antibody protein. The nano antibody FEL-1-Nb provided by the invention can be specifically bound with a cat main allergen FEL-1 protein, the unique amino acid sequence of the nano antibody FEL-1-Nb is shown as SEQIDNO: 1, high-affinity binding with the FEL-1 protein is ensured, the positive clone binding rate is high through phage display panning and ELISA verification, the phage recovery rate after the third round of panning is increased by more than 1000 times compared with the first round of panning, and the positive clone binding rate is higher than that of the first round of panning. Therefore, the nano antibody has excellent targeted recognition capability.

The present invention relates to the use of a combination of a saccharide and glycerol for skin protection against undesirable bacteria. The present invention is particularly useful in the formulation of compositions that act as prebiotics for commensal skin bacteria such as S. epidermidis to produce metabolites such as lactic acid, which, through the present invention, has been shown to inhibit the growth of undesirable bacteria such as E. coli and S. aureus, among others. The present invention is especially useful because it provides both short-term (i.e., rapid) and long-term (or sustained) protection.

The invention discloses a recombinant bacterium capable of increasing the yield of alpha-bisabolol as well as a preparation method and application of the recombinant bacterium, and belongs to the technical field of microorganisms. The invention aims to improve the yield of alpha-bisabolol and enhance the tolerance of a host to an organic solvent. The invention provides a recombinant bacterium for improving the yield of alpha-bisabolol. Escherichia coli is used as a starting strain; the method comprises the following steps of: overexpressing an acetyl CoA acyltransferase / HMG-CoA reductase mvaE gene, an HMG-CoA synthetase mvaS gene, a 2-methyl citrate dehydratase prpD gene, a mevalonate kinase ERG12 gene, a mevalonate 5-phosphate kinase ERG8 gene, a mevalonate 5-diphosphate decarboxylase ERG19 gene and an isopentenyl diphosphate isomerase idi gene, so as to obtain a recombinant vector; the gene is obtained from an alpha-bisabolol synthase gene of artichoke, a farnesyl diphosphate synthase ispA gene and an alpha-bisabolol synthase CcBOS gene of artichoke. The industrial process of synthesizing alpha-bisabolol by a biological method is promoted.

The invention relates to the fields of enzyme engineering and microbial fermentation production, in particular to an N-acetylglutamate synthetase mutant for producing N-acetyl blue and application of the N-acetylglutamate synthetase mutant. According to the invention, the N-acetylglutamate synthetase mutant EcargAV323A / S435A is constructed by researching the structure of N-acetylglutamate synthetase ArgA (EcargA) from Escherichia coli and mutating the 323rd site and the 435th site of EcargA protein in combination with a directed evolution technology, so that the N-acetylglutamate synthetase mutant EcargAV323A / S435A is constructed. When the engineering strain of the N-acetylglutamate synthetase mutant is used for producing the N-acetylobservation blue through fermentation, the yield of the N-acetylobservation blue can be remarkably improved, the generation of a by-product observation blue is reduced, the fermentation process is simplified, and the production cost is reduced. The N-acetylglutamate synthetase mutant and the engineering strain provided by the invention have good industrial application value.

The invention relates to the technical field of bioengineering, in particular to a preparation method and application of an antibacterial peptide, and the amino acid sequence of the antibacterial peptide is shown as SEQ ID No: 1 and is named as L8. The preparation method of the antibacterial peptide L8 comprises the following steps: S1, obtaining an L8 target gene segment; connecting an L8 target gene segment with a pLC vector to obtain a connection product; transforming the connection product into an escherichia coli DH5-alpha competent cell, and screening positive clones to obtain a pLC-L8 recombinant plasmid; s2, taking the pLC-L8 recombinant plasmid as a substrate, and carrying out cell-free protein synthesis reaction to obtain the antibacterial peptide L8, the cell-free protein synthesis system comprises 175 mM of potassium glutamate, 10 mM of ammonium glutamate, 2.7 mM of potassium oxalate, 33 mM of PEP, 38 mM of compound amino acid, 10 mM of magnesium glutamate, 2% (w / v) PEG-8000, 5 nM of pLC-L8 recombinant plasmid, 11.25 mM of lactose, 33.33% (v / v) of crude extract, 100 mg / mL of escherichia coli tRNA and 2.5 nM of T7 RNA polymerase. The antibacterial peptide L8 is obtained by optimizing the antibacterial peptide LRGG, and compared with the LRGG, the antibacterial peptide L8 subjected to cell-free protein synthesis reaction expression has better antibacterial activity and biological safety.

The invention discloses a conservative B cell epitope peptide of goose parvovirus VP3 protein, a nucleic acid molecule, a recombinant vector and application thereof. Conservative B cell epitope EW12 is inserted into F18 Escherichia coli Fod fimbriae, inert carrier bacteria S9H are introduced, recombinant bacteria capable of functionally exhibiting and expressing the EW12 conservative B cell epitope on the surface of the bacteria are obtained, the recombinant bacteria can specifically generate specific binding reaction with gosling plague egg yolk antibody and gosling plague vaccine immune serum, and the gosling plague egg yolk antibody and the gosling plague vaccine immune serum can be specifically combined with the gosling plague egg yolk antibody and the gosling plague vaccine immune serum. The method has the advantages that macroscopic agglutination particles are generated, cross agglutination reaction with other pathogen positive serum and healthy goose serum is avoided, the method is good in sensitivity, and the specific antibody can be detected in the 5th day after immunization at the earliest. A plate agglutination test directly mediated by the goose parvovirus VP3 protein conservative B cell epitope peptide EW12 has the advantages of specificity, sensitivity, convenience in operation and suitability for on-site large-scale rapid detection, and is expected to provide a new technical means for diagnosis, prevention and control and purification of GPV infection.

The present application relates to the technical field of fermentation engineering, and provides an engineered Escherichia coli for producing uroporphyrin as well as a construction method and application thereof.The present application uses Escherichia coli to express porphyrin synthase of thermophilic bacteria, performs whole-cell catalysis of 5-ALA to synthesize uroporphyrin under high-temperature conditions, and completely shields endogenous regulation; further, the Escherichia coli is wrapped by COF material to prevent the loss of enzymes in the cell recovery process; and a protein scaffold based on dockerin-cohesin is constructed to further improve the yield of uroporphyrin III.The present application creates a brand-new uroporphyrin high-temperature whole-cell catalysis process, realizes the efficient production of uroporphyrin, and provides a basis and idea for the industrial production of uroporphyrin.

The invention discloses a protein sequence analysis method, equipment, a medium and a product, and relates to the technical field of combination of biotechnology and artificial intelligence. The method comprises the steps that a first protein sequence is obtained, corresponding first embedding expression is constructed, and the first protein sequence is an exogenous protein sequence which is expressed in Escherichia coli or is to be expressed in Escherichia coli and is not from Escherichia coli; inputting the first embedded representation into a pre-trained proteotoxicity analysis model to obtain a prediction result aiming at whether the first protein sequence is toxic to escherichia coli or not; the model is a convolutional neural network model based on a channel attention mechanism and a space attention mechanism. According to the technical scheme provided by the embodiment of the invention, the problem that a method for analyzing the toxicity of the escherichia coli by aiming at the protein sequence cannot give consideration to both efficiency and accuracy is solved, and the toxicity of the endogenous or exogenous protein sequence expressed in the escherichia coli to the escherichia coli can be efficiently, stably and accurately predicted and analyzed.

The invention discloses a method for catalytically synthesizing adenosine triphosphate by using microcrystalline cellulose carrier purification immobilized enzyme, which comprises the following steps: preparing bacterial suspension by using escherichia coli wet thalli and Tris-HCL buffer solution, crushing, centrifuging, and taking supernate to obtain crude enzyme; adding a microcrystalline cellulose carrier and the wet thalli into the crude enzyme liquid, and washing the immobilized enzyme after immobilization to obtain the immobilized enzyme; the method comprises the following steps: adding immobilized enzyme adenosine kinase and immobilized polyphosphate kinase into a substrate system with the volume of 1L according to a weight ratio, and starting a catalytic reaction under the conditions that the pH is 5.5-7.5 and the temperature is 20-40 DEG C; after catalysis is finished, the immobilized enzyme adenosine kinase and the immobilized polyphosphate kinase are subjected to solid-liquid separation with reaction liquid through a Buchner funnel, the immobilized enzyme continues to be subjected to catalytic reaction, and the method for preparing the immobilized enzyme is simple in mode, low in cost, easy to industrially produce, high in stability and capable of being repeatedly used for many times, and products are easy to separate.

A vaccine comprising effective amounts of i) E. coli colonization factor antigens comprising CFA / I, CS3, CS5 and CS6 antigens; ii) a heat labile enterotoxin B subunit antigen being an LCTBA protein; and iii) an adjuvant being double mutant (R192G / L211A) of E. coli heat-labile toxin (dmLT), for use in inducing protective immunity against diarrheal disease caused by Salmonella spp. and / or Shigella spp.

This invention discloses a recombinant vector, recombinant bacteria, and fermentation method for high-yield GHK production, belonging to the field of biomedical technology. The recombinant expression vector of this application comprises a bicistronic expression cassette controlled by a T7 / lac heterozygous promoter, sequentially containing the encoding (GHK). n The vector encodes the first cistron of the polypeptide and the second cistron, where n is an integer from 2 to 200. When this vector is transformed into *E. coli* BL21, the resulting recombinant bacteria can simultaneously express (GHK) after IPTG induction. n Polypeptides and trypsinogen. During fermentation, trypsinogen is activated and enables the processing of (GHK). n In situ enzymatic cleavage of peptides efficiently releases GHK. This invention integrates the traditional multi-step process into a "one-step fermentation," simplifying the production process and reducing purification difficulty. Examples show that the GHK yield can reach up to 3.9 g / L, providing an efficient and convenient new strategy for the large-scale biomanufacturing of GHK.

The application discloses a method for producing deoxythymidine triphosphate by using a recombinant strain, and comprises the following steps: step 1: using a CRISPR / Cas9-mediated gene editing method to perform targeted modification on an E. coli genome, and the targeted modification comprises the following contents: a. knocking out a nucleoside triphosphate pyrophosphatase gene (mazG / yhdE) to block a path of degrading dTTP into dTMP; b. knocking out a nucleotide nucleosidase gene (ppnN) to block a path of degrading dTMP into thymine; and c. knocking out a nucleotidase gene (yfbR / yfdR / ushA / umpH / umpG / yjjG) to block a path of degrading dTMP into dT. The application provides a method for producing deoxythymidine triphosphate by using a recombinant strain, and the conversion rate of the method reaches 80% to 90%, and after ion exchange chromatography purification, the purity can reach more than 99%.

The invention provides a composition comprising a Plasmodium species multimeric protein capable of forming a nanoparticle and at least one antigen of interest, wherein the multimeric protein comprises a monomer chosen from Plasmodium species pyridoxal 5'-phosphate synthase (PLP), chaperone 60 protein (Cpn60), and caseinolytic protease (Clp). In embodiments, the invention provides the composition wherein the monomers assemble to form a multimeric nanoparticle and / or which comprises an adjuvant. The invention further provides a nucleic acid encoding the multimeric protein and the at least one antigen of interest, E. coli comprising the nucleic acid, and the use of such in a method for producing the inventive multimeric protein and the at least one antigen of interest. Also provided are a method and use of the inventive multimeric protein and the at least one antigen of interest for immunizing a subject against Plasmodium species.

The invention discloses a recombinant full-length human-derived III-type collagen as well as a preparation method and application of the recombinant full-length human-derived III-type collagen. The method comprises the following steps: replacing at least one corresponding rare codon of glycine, proline, arginine, leucine, isoleucine, valine and / or glutamic acid host bacteria in a Gly-Pro-X or Gly-X-Pro tripeptide structure coded by a wild full-length human III-type collagen gene sequence with a synonymous codon used by the host bacteria at high frequency; the translation efficiency in prokaryotic systems such as escherichia coli is obviously improved; the method comprises the following steps: designing 6-12 gene segments with overlapping sequences, splicing by adopting an overlapping extension PCR (Polymerase Chain Reaction) technology to obtain a full-length optimized gene, constructing the full-length optimized gene to an expression vector, and transforming the full-length optimized gene into host bacteria for induced expression; the expression product exists in the form of an inclusion body, and the natural conformation of the expression product is recovered through in-vitro renaturation; according to the method, high-efficiency expression and active preparation of the full-length human-derived III-type collagen in a prokaryotic system are realized.

This invention discloses a method for preparing and applying plant sulfonated small peptide PSK based on synthetic biology, belonging to the field of biotechnology. Based on the design concept of synthetic biology, this invention constructs an orthogonal synthetic system composed of genetic code expansion technology and SUMO fusion protease digestion technology. A specific PSK dotted vector and a pUltra-sY vector are co-transformed into *E. coli* to construct a genetically engineered strain. The sulfonated small peptide PSK precursor is expressed in this genetically engineered strain, and mature plant sulfonated small peptide PSK is obtained through specific hydrolysis by SUMO protease. This method significantly improves the synthesis efficiency and purity of sulfonated small peptides and has broad application prospects in agricultural production and biotechnology.

The present invention relates to YGHJ polypeptides having novel glycosylation patterns. The glycosylated polypeptides are expressed in avirulent recombinant strains of naturally occurring pathogenic bacteria, which produce glycosylated YGHJ polypeptides that resemble the wild-type polypeptide to a higher degree than polypeptides expressed in E. coli production strains. The present invention also relates to uses of such polypeptides and production strains.

The invention discloses bacillus subtilis for recombinant expression of a hermetia illucens HIAMP0438 gene and a construction method of the bacillus subtilis, and belongs to the technical field of gene engineering. The hermetia illucens recombinant protein used in the invention is obtained by expression of bacillus subtilis WB800N transferred into a pHT43-HIAMP0438 high-efficiency expression vector, and the pHT43-HIAMP0438 high-efficiency expression vector is obtained by a homologous recombination technology, so that high-level expression of the HIAMP0438 gene is realized, the HIAMP0438 gene can be efficiently secreted out of cells, the preparation process of the recombinant protein is greatly simplified, and the production cost is reduced. According to the present invention, the recombinant protein can significantly inhibit the growth of Escherichia coli, Salmonella and Listeria monocytogenes, and the recombinant protein can be used as the animal health product, and can be used for preventing and treating pig and chicken intestinal diarrhea caused by Escherichia coli and Salmonella and food-borne digestive tract diseases caused by Listeria monocytogenes.

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 invention discloses a gallic acid-based cationic photodynamic antibacterial agent with sterilizing, anti-infection and wound healing promoting effects and a preparation method thereof, and belongs to the technical field of antibacterial agent synthetic chemistry. The cationic photodynamic antibacterial agent EY-QEGDM-MG is prepared by taking a natural compound gallic acid as a raw material and carrying out ring opening polymerization and quaternization reaction with photosensitizer eosin EY and ethylene glycol diglycidyl ether (EGDE), and the polymer shows an excellent antibacterial effect on escherichia coli and multi-drug-resistant MRSA germs under the action of illumination, and can be used for preparing a cationic photodynamic antibacterial agent EY-QEGDM-MG. The polymer has good blood compatibility and cell compatibility, in addition, the polymer can kill bacteria around infected wounds and can rapidly promote wound healing, and therefore the polymer can provide a new method for photodynamic antibacterial agents for treating the infected wounds in hospitals.

The invention provides a method for synthesizing melanin nanoparticles by using escherichia coli, and belongs to the technical field of biological genetic engineering. According to the method, a bacillus megaterium-derived tyrosinase gene Tyr1 (SEQ ID NO.2) after codon optimization is taken as a target gene, a recombinant expression plasmid pET-24a-Tyr1 is constructed, and the recombinant expression plasmid pET-24a-Tyr1 is transformed into an escherichia coli BL21 (DE3) competent cell to obtain the genetically engineered bacterium. After the engineering bacterium induces expression of tyrosinase through IPTG (isopropyl-beta-d-thiogalactoside), polymerization of an L-tyrosine substrate is catalyzed in the presence of CuSO4 to obtain high-purity melanin nanoparticles. The melanin nano-particles synthesized by the method are uniform in particle size, have wide-spectrum strong absorption characteristics in a wavelength range of 400-800nm, show excellent photo-thermal performance, free radical scavenging capacity and biocompatibility, and have wide application prospects in the fields of biomedicine and functional materials.

Antimicrobial eyewear features frames infused with or coated with antimicrobial additives, thereby offering continuous protection by actively destroying and inhibiting the growth of bacteria, fungi, parasites, and some viruses. The lenses may also have an antibacterial coating that destroys and inhibits bacterial growth. In some examples, the lenses are treated with a specialized strengthening liquid, wherein the liquid contains nano components that release heavy metal ions capable of invading the cell walls of bacteria, leading to bacterial elimination, destroying DNA molecules and proteases within the bacterial cells, denature viral proteins, break DNA chains, and result in cell death. Additionally, the strengthening liquid reduces dehydrogenase activity and interacts with various protein groups within the cell, thereby reducing the activity of these groups and effectively inhibiting the growth of E. coli and other bacteria on the lens surface.