45 results about "Bacillus coli" patented technology

The application discloses a method for improving the fermentation efficiency of soy sauce pool type fermentation, which is characterized by the following steps: using the self-source microorganism in the fermentation tank to carry out fermentation outside the fermentation tank, combining with the fermentation liquid of Lactobacillus reuteri for synergistic fermentation, and then returning the fermentation liquid to the fermentation tank for pouring and utilization, so as to realize the promotion of the self-source microorganism in the fermentation tank to the soy sauce fermentation. The self-source microorganism is fermented and cultured by reducing the salinity outside the fermentation tank and adding a proper amount of starch raw material, and the fermentation liquid with high activity of protease can be prepared in a short time, which is returned to the fermentation tank for pouring and utilization, so as to improve the degree and efficiency of protein hydrolysis in the fermentation tank. The Lactobacillus reuteri uses the fermentation liquid of the soy sauce mash in the fermentation tank as the basic nutrient source and ferments together with a proper amount of white granulated sugar to produce the fermentation liquid with the function of inhibiting Escherichia coli, so as to resist the Escherichia coli pollution in the fermentation process of the self-source microorganism outside the fermentation tank, guarantee the safety of the returned pouring fermentation liquid, and further improve the production efficiency of the soy sauce pool type fermentation technology.

The invention provides a beta-glucosidase mutant from Paenibacillus phyllosphaerae, and a method for efficiently preparing rare ginsenoside F2 by using an enzyme method and a whole-cell method, and particularly provides a beta-glucosidase mutant from Paenibacillus phyllosphaerae and a method for efficiently preparing rare ginsenoside F2 by using a beta-glucosidase mutant from Paenibacillus phyllosphaerae. The method comprises the following steps: engineering-modifying beta-glucosidase by utilizing computer-aided design, constructing a mutant library, carrying out primary screening and secondary screening to obtain two high-activity mutants Q7D and G189A, constructing a combined mutant Q7D / G189A, transforming the combined mutant Q7D / G189A into genetically engineered bacterium escherichia coli for expression, and producing F2 by utilizing a whole-cell method. Finally, the highest yield of 18.01 g / L is achieved after the reaction is carried out for 10 h in a 5 L fermentation tank and is 6.82 times that of a shake flask, and the purity of F2 reaches up to 82.20% after the reaction is carried out for 24 h finally. The invention not only provides an efficient solution for large-scale production of rare saponin F2, but also provides a transferable framework for designing and engineering diversified glycoside hydrolase in customized biological catalysis.

The invention discloses a Rogowski eutrophy alkali-producing engineering strain for producing p-coumaric acid as well as a construction method and application of the Rogowski eutrophy alkali-producing engineering strain. The preparation method comprises the following steps: by taking a chemoautotrophic microorganism Ropriavidus alcaligenes H16 as an original strain, firstly, by knocking out a synthetic route of a strain poly-3-hydroxybutyrate (PHB), introducing a tyrosine ammonia lyase gene from Rhodotorula glutinis to construct a basic engineering strain capable of producing p-coumaric acid, and then, carrying out fermentation on the basic engineering strain to obtain the p-coumaric acid. Then, endogenous 3-deoxy-7-phosphoheptanone acid synthase gene aroG1 and chorismate synthase gene aroC are overexpressed, and the total copy is increased, so that the p-coumaric acid synthetic pathway flux of the engineering strain is enhanced; and introducing NAD (P) transhydrogenase gene pntAB from Escherichia coli to improve the supply of cofactors, so as to finally obtain the eutrophy alcaligenes Rosei engineering strain capable of synthesizing p-coumaric acid by using CO2.

The present invention relates to a composition that is used to primarily disrupt and remove biofilm from surfaces. This is achieved using a composition comprising a bacteriophage capable of lysing bacteria selected from one or more of Pseudomonas aeruginosa, Acinetobacter baumanii, Staphylococcus aureus, and E.coli; and a Bacillus bacterial spore in the presence of a specific surfactant of the poloxamer type.

The invention belongs to the technical field of membrane separation, and particularly relates to a quercetin-doped reverse osmosis composite membrane, a preparation method thereof and a water purification method. The quercetin-doped reverse osmosis composite membrane comprises a polysulfone microfiltration base membrane and a quercetin-doped polyamide selection layer, the quercetin-doped polyamide selection layer is attached to the surface of at least one side of the polysulfone microfiltration base membrane; the quercetin-doped polyamide selection layer comprises quercetin and a polyamide skeleton, and the quercetin and the polyamide skeleton are connected through an ester bond and / or a hydrogen bond. The quercetin-doped reverse osmosis composite membrane at least meets one of the following conditions: the surface roughness is 121 nm to 199 nm; the water contact angle is 50-60 degrees; under the conditions of 20 bar and 25 DEG C + / -1 DEG C, the retention rate on a 2000 mg.L <-1 > NaCl solution is greater than or equal to 95%; the Zeta potential is-30mV to-60mV when the pH value is equal to 7; the sustained release rate of quercetin is 0.1 [mu] g.cm <-2 >. D <-1 >-10 [mu] g.cm <-2 >. D <-1 >; the killing rate of escherichia coli is greater than or equal to 90%; and the killing rate of staphylococcus aureus is greater than or equal to 90%.

The invention relates to a method for extracting roselle anthocyanin through enzymolysis-ultrasonic assistance, a product and application of the product. The method comprises the following steps: degreasing roselle powder, and performing enzymolysis for 24 hours by using cellulase and pectinase (20U / g respectively) under the conditions that the pH is 5.0 and the temperature is 40 DEG C; an acetone-hydrochloric acid mixed solution (the volume fraction of hydrochloric acid is 36%) with the liquid-material ratio being 10: 1 serves as an extracting agent, and ultrasonic extraction is conducted for 34 minutes at the temperature of 58 DEG C and the power of 160 W; and finally, centrifuging, extracting with ethyl acetate, and purifying to obtain an anthocyanin product. According to the method, the extraction rate reaches 3.087 mg / g, the main component of the product is cyanidin-3-glucoside, the antioxidant and antibacterial activity is remarkable, the scavenging rates of DPPH, ABTS and hydroxyl radicals are 86.26%, 81.34% and 93.75% respectively under the concentration of 3.0 mg / mL, and the scavenging rates are superior to those of vitamin C with the same concentration; under the concentration of 11mg / mL, the compound has an obvious inhibition effect on escherichia coli and staphylococcus aureus. The process is efficient and mild, the product activity is excellent, and the method is suitable for development and application of natural antioxidants and antibacterial agents.

The application discloses a colloidal gold test strip for distinguishing between wild toxin infection and vaccine immunization of porcine pleuropneumonia actinobacillus and application. The test strip of the application takes ApxIVA truncated protein with an amino acid sequence shown as SEQ ID NO. 3 as an antigen, the truncated protein can be soluble expressed in E. coli, and the structure and function of the truncated protein are close to those of natural apxIVA. The test strip of the application comprises a sample pad, a colloidal gold pad, an NC membrane, a water absorption filter paper and a bottom plate, the colloidal gold pad is coated with gold-labeled apxIVA truncated protein and gold-labeled chicken IgY antibody, and the C line and the T line of the NC membrane are fixed with goat anti-chicken IgY antibody and apxIVA truncated protein. The test strip only needs 25 muL of pig serum to make detection within 5-10 min, and can distinguish between APP wild strain infection and gene deletion vaccine APP-HB-04M immunized serum samples.

The application discloses an L-aspartate alpha-decarboxylase with improved substrate tolerance, and the L-aspartate alpha-decarboxylase is derived from Bacillus subtilis and is subjected to site-directed mutation, i.e., phenylalanine at the 4th site is changed into tryptophan, isoleucine at the 33rd site is changed into alanine, and isoleucine at the 88th site is changed into tryptophan, so as to obtain an enzyme mutant; the mutant is recombined into E. coli, and after expression is induced, the mutant catalyzes the substrate L-aspartate to generate beta-alanine. When the substrate addition concentration of the whole cell catalytic system is 60 g / L, the conversion rates of the three enzyme mutants T4W, I33A and I88M can reach about 90%, and the yields are 1.2, 1.3 and 1.2 times of that of the unmutated strain respectively, and the substrate tolerance is obviously improved; the combined mutation also has a certain improvement on the substrate tolerance, and the finding has important research value for industrial preparation of beta-alanine.

The present disclosure provides, among other things, methods for removing linear ribonucleic acid molecules from a sample by contacting the sample with ribonuclease R (RNase R) from a thermophilic organism, for example, Geobacillus stearothermophilus, Fervidobacterium pennivorans or Thermus thermophilus expressed and purified in E.coli. Also provided herein are methods of producing circular RNA and removing uncircularized linear RNA molecules, linear RNA byproducts, or linear RNA side products using an RNase R expressed or purified from a thermophilic organism. The present disclosure also provides methods of purifying RNase R from a thermophilic organism in E. coll, wherein the method comprises heat treatment at high temperatures, and compositions and kits comprising the same.

The present application relates to the field of genetic engineering and biological enzyme depolymerization of PET plastics, and particularly relates to a hydrophilic PET depolymerase mutant and application thereof. The present application obtains a hydrophilic PET depolymerase mutant V68R, or A137R or I243R by mutating the 68th, or 137th, or 243th amino acid residue of the PETase protein amino acid sequence into R. Compared with the wild-type PETase protein, under the premise of ensuring the depolymerization efficiency of PET / BHET and effectively depolymerizing PET / BHET, the expression level of soluble protein is improved, and the formation of inclusion bodies is reduced in the expression system of Escherichia coli, Bacillus subtilis or Pichia pastoris, which has economic feasibility, PETase high-yield universality, and wide application prospect.

This invention belongs to the field of genetic engineering technology and discloses a high-efficiency expression method for recombinant collagenase and its application in the preparation of bovine bone collagen peptides. The collagenase gene derived from Bacillus sp. HUB-I-004 strain (accession number J9CTX3) was optimized using E. coli-preferred codons. A recombinant expression vector was constructed and transformed into E. coli BL21(DE3). After optimization of induction conditions and Ni-NTA affinity purification, a highly active recombinant collagenase with a specific activity of 231.05 U / mg was obtained. Bovine bone collagen was extracted using a high-temperature, high-pressure method. Bovine bone collagen peptides were prepared under optimal conditions of a substrate concentration of 10 mg / mL, an enzyme addition of 20%, and enzymatic hydrolysis at 37℃ for 8 h, significantly improving peptide yield. The obtained product is mainly composed of small molecule peptides and exhibits significant osteoblast proliferation-promoting activity, making it widely applicable in the preparation of health foods and pharmaceuticals.

The invention discloses a method for crystallizing BM3 protein in bacillus megaterium. The method comprises the following steps: constructing a gene for coding the BM3 protein into an expression vector, carrying out induced expression in escherichia coli, carrying out affinity chromatography purification, excising a fusion tag, carrying out gel filtration purification, incubating with cofactors FAD, FMN and NADPH to form a compound, and crystallizing under a specific pool liquid condition through a seated drop gas phase diffusion method. According to the method, the high-quality BM3 protein crystal suitable for X-ray diffraction analysis can be obtained, and a basis is provided for analyzing the three-dimensional structure of the BM3 protein crystal and researching an electron transfer mechanism.

The invention discloses a bacillus subtilis genome integrated plasmid for efficient and stable expression of genes and application of the bacillus subtilis genome integrated plasmid in production of beta-galactosidase. The plasmid comprises a bacillus subtilis promoter, an RBS sequence, a terminator, a bacillus subtilis resistance gene, a genome integration homologous arm, an escherichia coli replicon and a resistance gene. The homologous arm is selected from upstream and downstream sequences of sites behind termination codons such as genes spxA, tatCY, rlmCD and the like, so that exogenous genes are accurately integrated to a plurality of non-essential sites on the premise of not damaging essential genes. The invention also provides a method for constructing a bacillus subtilis engineering strain for producing beta-galactosidase by using the plasmid. The integration system is high in expression level, stable expression can be achieved without adding antibiotics and inducers, the fermentation cost is remarkably reduced, the enzyme production efficiency is improved, and the integration system is suitable for industrial enzyme preparation production.

The invention discloses preparation of a mulberry leaf peptide and gallic acid synergistic antibacterial compound and application of the mulberry leaf peptide and gallic acid synergistic antibacterial compound in bacteriostasis and preservation, and belongs to the technical field of food preservation. The antibacterial compound comprises mulberry leaf peptide and gallic acid, and the mass ratio of the mulberry leaf peptide to the gallic acid is 5: (1-3). The preparation method of the antibacterial compound comprises the following steps: (1) obtaining mulberry leaf protein; (2) carrying out mixed fermentation on the mulberry leaf protein in a liquid medium by utilizing lactobacillus rhamnosus and lactobacillus reuteri to obtain mulberry leaf peptide; and (3) reacting the mulberry leaf peptide with gallic acid in any one of non-covalent binding, alkaline catalytic covalent binding or free radical grafting initiated covalent binding to prepare the gallic acid-mulberry leaf peptide compound. The compound has an antibacterial function of effectively inhibiting staphylococcus aureus and escherichia coli, and can remarkably improve the fresh-keeping effect of fruits, thereby laying a foundation for developing an innovative, safe and efficient natural fresh-keeping agent in the food industry.

The invention belongs to the technical field of aquatic product pathogen gene editing, and particularly relates to a target gene knockout method for photobacterium damsela subsp. Piscicida (PDP), which is characterized in that the target gene knockout method for the photobacterium damsela subsp. Piscicida (PDP) is disclosed. The method comprises the following steps: obtaining a DNA fusion fragment with deletion of a target region fragment of a target gene (MshL) by adopting overlapping PCR (Polymerase Chain Reaction), constructing a recombinant vector by using the obtained DNA fusion fragment, and obtaining the target gene knocked-out photobacterium damnieri subspecies fish by taking escherichia coli S17-1 lambda pir as a donor bacterium of a recombinant plasmid and PDP as a recipient bacterium. Specific knockout of the PDP specific gene is achieved for the first time, the knockout efficiency is high (the single-exchange positive rate is 29.2%, and the double-exchange positive rate is 30.8%), the cost is low, and the method is suitable for construction of a PDP specific gene deleted strain and functional research of the specific gene.

The invention relates to a Juncao-sourced natural antibacterial, antiviral and environment-friendly clothing lining as well as a preparation method and application thereof. The lining of the garment is woven and formed in a weaving or knitting mode by taking Juncao regenerated cellulose fiber filaments as a core functional material; wherein the weaving mode comprises that warp and weft yarns adopt a full-fungus grass filament framework A of fungus grass regenerated cellulose fiber filaments, or warp yarns adopt common polyester fiber filaments / common viscose fiber filaments, and weft yarns adopt a composite synergistic framework B of fungus grass regenerated cellulose fiber filaments. The functions of the Juncao regenerated cellulose fiber filaments can be enhanced by combining with a nano-scale metal oxide finishing agent. The preparation method comprises the following green after-finishing processes: preparing the fiber filaments by a green and environment-friendly method, weaving and forming, and carrying out biological enzyme desizing, biological polishing, low-temperature setting and the like. The product has excellent antibacterial and antiviral properties (for example, the 24-hour bacteriostasis rate for staphylococcus aureus, escherichia coli and candida albicans is greater than or equal to 95%, and the activity rate for resisting H3N2 and H1N1 avian influenza viruses is greater than or equal to 90%), has the characteristics of high comfort and high biodegradation rate, and is suitable for linings of high-end clothes such as business suits, overcoats, down jackets and the like. Unification of functions, comfort and environmental protection is achieved, and the good industrialization prospect is achieved.

The application provides a rhodioloside production strain and a construction method and application thereof, the strain lacks tyrR, feaB, ldhA, ushA, pykF genes, up-regulates tktA , aroG fbr 、 tyrA fbr、 pgm, galU, gntK the transcription level of a gene, and heterologously introduces a TDC gene from Lactobacillus brevis, a TYO gene from Micrococcus luteus, a ARO10 gene from Saccharomyces cerevisiae, and a ADH6 gene, heterologously introduces a GDH gene from Bacillus and a sugar transferase Oft8gt1 gene from Osmanthus fragrans; the construction method is to reconstruct the metabolic network of Escherichia coli to rhodioloside through metabolic engineering and genetic engineering means, which can effectively utilize glucose to synthesize rhodioloside from scratch, improve the production level of rhodioloside, and lay a solid foundation for the industrialized scale production thereof.

The invention discloses phosphorylated bald calvatia polysaccharide-starch hemostatic microspheres as well as a preparation method and application thereof, and belongs to the technical field of biological medicines. The preparation method comprises the following steps: firstly, dissolving bald puffball polysaccharide in DMF (Dimethyl Formamide), and carrying out phosphorylation modification in the presence of sodium tripolyphosphate under an alkaline condition to obtain phosphorylated bald puffball polysaccharide; then, EDC / NHS is used for activating moderately-crosslinked starch microspheres, the moderately-crosslinked starch microspheres and the phosphorylated polysaccharide are subjected to covalent coupling at specific pH and temperature, and finally the hemostatic microspheres are prepared. The hemostatic microspheres combine the excellent procoagulant, anti-inflammatory and bacteriostatic biological activities of phosphorylated polysaccharide and the physical characteristics of rapid water absorption and expansion of starch microspheres, so that the synergistic efficient hemostasis of physical barrier and biochemical activation is realized. The product can shorten the blood coagulation time (APTT) and has an inhibition effect on staphylococcus aureus and escherichia coli.

This invention belongs to the field of biomimetic nanomaterials technology, specifically providing a method for synthesizing biomimetic nanoenzymes and their application in antibacterial, anti-mold, and preservation of fruits and vegetables. The synthesis of the biomimetic nanoenzyme includes the following steps: (1) adding glutamic acid to deionized water and heating and stirring until a transparent or homogeneous glutamic acid solution is formed; (2) adding zinc sulfate and cerium sulfate to deionized water and ultrasonically dispersing them uniformly to obtain a bimetallic salt solution; (3) adding the bimetallic salt solution to the glutamic acid solution according to a molar ratio of zinc in zinc sulfate, cerium in cerium sulfate, and glutamic acid of 3~4:0.5~0.9:1, followed by the addition of an organic solvent, stirring under heating conditions, and then washing, drying, and grinding to obtain the biomimetic nanoenzyme. Experiments show that the biomimetic nanoenzyme Zn of this invention… 3.5 / Ce 0.9 -Glu has a bactericidal rate of 99.41% against Escherichia coli and 98.28% against Staphylococcus aureus, which can extend the storage period of cherry tomatoes to 12 days.

The invention discloses a BCG3973 gene knocked-down recombinant bacillus calmette guerin vaccine strain as well as a construction method and application thereof. According to the invention, a CRISPRi / dCas9th1 technology is utilized to block RNA polymerase movement in space through a compound formed by crRNA, dCas9 protein and sgRNA at a transcriptional level, so that the expression of the BCG3973 gene in the BCG vaccine is inhibited. After being treated by the recombinant bacillus calmette guerin bacterial strain, the immune-related pathways of macrophages, such as a cytokine-cytokine receptor action pathway, a Ca < + + > signal pathway and pathways such as PPAR and JAK-STAT, are obviously increased, and IL-1beta, TNF-alpha, antiviral protein and calmodulin with higher levels are expressed, so that the recombinant bacillus calmette guerin bacterial strain has stronger bactericidal ability on escherichia coli. Mouse in-vivo experiments show that the recombinant bacillus calmette-guerin bacterial strain has a very good protection effect on escherichia coli infection and endotoxemia caused by lipopolysaccharide, and shows higher survival rate and stronger capability of eliminating heterologous substance infection under attack of a lethal dose of Candida albicans.

The invention relates to the technical field of traditional Chinese medicine fermentation, in particular to a preparation method of compound traditional Chinese medicine probiotic fermentation liquor for treating chicken colibacillosis, the fermentation liquor and application. Wherein the traditional Chinese medicine composition comprises the following raw materials: coptis chinensis, golden cypress, scutellaria baicalensis, isatis root, rheum officinale and liquorice; s2, preparing a strain culture medium; s3, adding the compound extracting solution into a strain culture medium to prepare a fermentation culture medium; s4, inoculating probiotics to the fermentation culture medium for fermentation; a traditional medicinal and edible traditional Chinese medicine compound is fermented by using bacillus subtilis, and the traditional Chinese medicine compound is biologically converted, so that the strain activity and the effectiveness of the medicinal and edible traditional Chinese medicine compound can be remarkably enhanced, and the content of active substances in a traditional Chinese medicine compound extracting solution is increased; meanwhile, the compounds in the compound can provide nutrient substances for the growth of the bacillus subtilis and promote the growth of the bacillus subtilis, so that the effects of the traditional Chinese medicines and the probiotics are exerted to the greatest extent.

The invention relates to a multi-antibacterial composite hydrogel dressing and a preparation method thereof, and the preparation method is characterized by comprising the following steps: (1) dissolving acrylamide and acrylic acid in water according to a mass ratio of 3: 7-7: 3; (2) sequentially adding 0.2 to 35 percent of vanadium trichloride and 0.09 to 15 percent of mangiferin, and uniformly stirring; (3) continuing to add 0.2-2% of N, N '-methylene bisacrylamide and 0.2-2% of ammonium persulfate, stirring and dissolving, adding 0.2-2% of N, N, N', N '-tetramethylethylenediamine, uniformly mixing, and injecting into a mold; (4) standing and reacting at room temperature for 6-48 hours to form tough brown hydrogel; and soaking and washing the brown hydrogel with deionized water for 3-5 times, and then cutting. The multi-antibacterial composite hydrogel dressing has the advantages that the antibacterial rate of the multi-antibacterial composite hydrogel dressing to staphylococcus aureus and escherichia coli is not lower than 70%, and the antibacterial rate can be increased to 80% or above under the assistance of near-infrared light.

According to the method, the glycerol-ethanol mixture is creatively adopted as the cosolvent, preparation of the lignin with the high sulfonation degree is achieved, and the technical effect is remarkable. Wherein the use amount of the cosolvent is 10-30 wt% of water in the sulfonation reaction, and the content of glycerol in the cosolvent is 60-90 wt%. The inventor accidentally finds that lignin with high sulfonation degree can be obtained by taking a proper amount of glycerol-ethanol mixture as a cosolvent in the preparation process of sulfonated lignin. On the basis, the lignin sulfonate and a cationic auxiliary agent are compounded to obtain the biological adhesive, so that the adhesive performance is improved. Compared with the prior art, the preparation method is simple, easy to operate and low in cost, has automatic continuous preparation conditions and has wide industrial application prospects. In addition, in the sulfonated lignin preparation process, traditional Chinese medicine residues are adopted as raw materials; in preparation of the biological adhesive, traditional Chinese medicine soup is adopted to replace part of water, and the traditional Chinese medicine-based biological adhesive is obtained. The bacteriostasis rate of the traditional Chinese medicine-based biological adhesive on escherichia coli and staphylococcus aureus is greater than 90%, the cytocompatibility is good, and the technical problem that in the prior art, a traditional Chinese medicine patch is prone to causing allergy is solved.

本发明提供一种植物乳杆菌（Lactiplantibacillus plantarum）DC76及其应用，所述菌株分离自贵州传统发酵食品豆豉，已于 2025 年 11 月 26 日保藏于广东省微生物菌种保藏中心，保藏号为GDMCC No.67360。该菌株具备优异的耐酸、耐胆盐特性，对大肠杆菌、沙门氏菌、巴氏杆菌等多种动物致病菌具有显著抑制作用；可调节肠道微生态平衡，上调肠道紧密连接蛋白 ZO‑1、Occludin 表达，增强肠道屏障完整性、降低肠道通透性，修复受损肠道屏障，同时调节肠道免疫微环境、减轻炎症反应。本发明所述菌株可用于制备动物饲料添加剂、微生态制剂及生物发酵剂，在畜禽健康养殖及替抗领域具有良好应用前景。

The invention relates to a protein delivery system, a preparation method and modification and application thereof, and belongs to the technical field of biology. The protein delivery system disclosed by the invention comprises a structural protein derived from a Yersinia similia 228 strain, a regulatory factor derived from a Photorhabus asymbiosis 43949 strain, and a signal peptide derived from a pathogenic bacterium, a yersinia and a non-symbiotic photobacterium, and is characterized in that the protein delivery system comprises the structural protein derived from the Yersinia similia 228 strain and the regulatory factor derived from the Photorhabus asymbiosis 43949 strain. The protein delivery system disclosed by the invention can be expressed in escherichia coli and assembled into the YPCIS protein compound, and the effect protein can be loaded to the YPCIS protein compound through the signal peptide; on the basis, the recognition region of the protein coded by the Cis gene cluster is further subjected to adaptive transformation, so that the YPCIS protein compound can target a target cell, and the specific delivery of the effect protein is realized.

The invention discloses a high-barrier antibacterial CPP composite film and a preparation method thereof, and belongs to the technical field of CPP composite films, the high-barrier antibacterial CPP composite film is of a three-layer co-extrusion structure formed by a heat sealing layer, a core layer and a corona layer which are sequentially arranged, and the core layer is prepared from the following raw materials in parts by weight: 80-95 parts of polypropylene resin, 0.5-3 parts of modified nano silicon dioxide and 2-5 parts of a compatilizer. The three-layer co-extrusion structure sequentially comprising the heat sealing layer, the core layer and the corona layer is arranged, the modified nano silicon dioxide subjected to gamma-aminopropyltriethoxysilane surface grafting treatment is added into the core layer, and meanwhile the chitosan-silver composite antibacterial agent is added into the heat sealing layer; according to the present invention, with the composite film, the oxygen and water vapor barrier property and the antibacterial property are significantly improved while the good heat sealing performance and the good surface corona treatment effect of the composite film are maintained, the oxygen transmission rate can be as low as 3.8 cm / (m.24h. 0.1 MPa), and the antibacterial rates on escherichia coli and staphylococcus aureus can achieve more than 98.9%.

The application discloses a peppermint essential oil nanoemulsion and a preparation method thereof. The preparation method comprises the following steps: S1, 0.275 mL of peppermint essential oil, 0.25 mL of polyglycerol-4-decanoate / thymol (1 / 2, mol / mol), 0.94 mL of betaine / glycerol (1 / 3, mol / mol) and 3.76 mL of ultrapure water are added into every 5.225 mL of a mixed system, the mixed system is uniformly shaken to obtain a coarse emulsion; and S2, the coarse emulsion is subjected to ultrasonic emulsification for 30 min to prepare the peppermint essential oil nanoemulsion. The peppermint essential oil nanoemulsion prepared by the method is mostly in spherical shape and is uniformly distributed, and is still in a stable state after being placed at different temperatures for 14 days, and the emulsion is stable in property. Anti-inflammatory effect test results show that, compared with the peppermint essential oil, the nanoemulsion reduces NO production in the presence of lipopolysaccharide (LPS) at a lower concentration. Bacteriostatic effect test results show that the peppermint essential oil nanoemulsion has a greater inhibitory effect on Staphylococcus aureus and Escherichia coli than the peppermint essential oil of the same concentration, and better antibacterial performance is obtained.

The application belongs to the technical field of microorganisms, and particularly relates to a Citrobacter freundii BD11 with anaerobic CO2 fixation function and application of the Citrobacter freundii BD11 in synthesis of cationic polysaccharide. The Citrobacter freundii BD11 is preserved in the China General Microbiological Culture Collection Center on July 6, 2026, and the preservation number is CGMCC No. 38727. The Citrobacter freundii BD11 is a gram-negative facultative anaerobe, can synthesize cationic polysaccharide by using CO2 and acetate under anaerobic conditions, and the CO2 fixation amount is 41-45 mM within 21 days, so that the resource utilization of CO2 is realized, and the green biological manufacturing concept is met. The synthesized cationic polysaccharide is a heteropolysaccharide structure, the monosaccharide composition and relative content are as follows: 70-75% of glucosamine, 17-20% of galactosamine, and 8-10% of mannose. In addition, the cationic polysaccharide also has high efficient bacteriostatic activity, when the concentration of the cationic polysaccharide is greater than or equal to 0.2%, the inhibition rate on Escherichia coli K-12 is greater than or equal to 90% within 1 h.

This invention relates to the field of avian immunology, and more particularly to a universal monoclonal antibody against Riemerella anatipestifer, a detection kit, and their applications. Specifically, this invention successfully designed a universal monoclonal antibody against Riemerella anatipestifer, and the detection kit developed based on this monoclonal antibody can rapidly detect the level of Riemerella anatipestifer serum antibodies in samples with high sensitivity and strong specificity. Furthermore, it shows no cross-reactivity with Enterococcus faecalis, Salmonella typhi, Escherichia coli, and Salmonella enteritidis, thus it can be used for rapid screening, epidemiological monitoring, and evaluation of vaccine immunization efficacy against Riemerella anatipestifer infection, with broad application prospects.