146 results about "Molecular weight cut-off" patented technology

The invention discloses a surface-enhanced tryptophan modified nanofiltration membrane as well as a preparation method and application thereof. Belongs to the field of water treatment membrane preparation. The invention aims to solve the technical problems of non-uniform pore size distribution and surface hydrophobicity of the conventional nanofiltration membrane. The method comprises the following steps: adding tryptophan into a piperazine water-phase solution, and carrying out interfacial polymerization with oil-phase trimesoyl chloride to prepare the tryptophan modified nanofiltration membrane. According to the preparation method, the diffusion rate of the piperazine monomer can be adjusted in the interfacial polymerization process by utilizing a similar surfactant structure of tryptophan, meanwhile, the tryptophan has hydrophilicity and can improve the hydrophilicity of the surface of an active layer, and the prepared modified nanofiltration membrane is reduced in molecular weight cut-off, improved in surface hydrophilicity and good in water resistance. The retention rate of organic micro-pollutants is improved, and meanwhile, good anti-pollution performance is achieved.

The invention discloses camel milk polypeptide with xanthine oxidase inhibitory activity and application thereof.The camel milk polypeptide is prepared by taking fresh camel milk as a raw material, conducting low-temperature centrifugation to remove fat, conducting triple enzymolysis through papain, pepsin and trypsin to obtain enzymatic hydrolysate, enabling the enzymatic hydrolysate to pass through an ultrafiltration membrane (the molecular weight cutoff is 10 kDa) to obtain filtrate, and conducting freeze-drying to obtain the camel milk polypeptide. The compound has xanthine oxidase inhibitory activity. The invention also discloses a small molecule polypeptide with xanthine oxidase inhibitory activity. The filtered solution is screened and combined with polypeptides by adopting a xanthine oxidase affinity ultrafiltration method, the activity of the polypeptides is verified through molecular docking and in-vitro enzyme inhibition, four small-molecule polypeptides with xanthine oxidase inhibitory activity are obtained, the sequence of the small-molecule polypeptides is shown as any one of SEQ ID NO.1-4, and the small-molecule polypeptides can be used for preparing drugs with the effect of inhibiting the uric acid level.

The invention discloses an implant-derived exosome which is prepared by the following steps: adding cleaned and crushed colored rice flour into a PBS (Phosphate Buffer Solution) with the pH value of 6-7.4, homogenizing at a high speed, adding alpha-amylase into rice milk, performing enzymolysis for 1-2 hours under the conditions that the pH value is 6-7.4 and the temperature is 90-97 DEG C, filtering, and standing filtrate overnight; carrying out gradient differential centrifugation at 4 DEG C, collecting supernate, filtering, carrying out ultracentrifugation on filtrate at 4 DEG C and 12000-15000g for 1.5-3 hours, and collecting precipitate; and re-suspending the precipitate, enriching by using an MWCO ultrafiltration tube with the molecular weight cut-off of 100kDa, collecting the precipitate at the bottom of the ultrafiltration tube, and re-suspending in a PBS buffer solution, thereby obtaining the product. The exosome can effectively inhibit the generation of inflammatory factors, has a good inhibition effect on various pathogenic bacteria, also has an anti-oxidation effect, and has application prospects in the fields of inflammation resistance, bacteria resistance, oxidation resistance and the like.

The invention discloses application of walnut peptide in preparation of a medicine for treating or preventing cognitive impairment of diabetes mellitus. The preparation process of the walnut peptide is as follows: after walnut protein is subjected to enzymolysis by alkaline protease, the molecular weight cut-off is 1t; and separating by using a 3kDa ultrafiltration tube to obtain the walnut peptide. The walnut peptide can effectively reduce the blood sugar level of a diabetic model mouse, regulate the disorder effect of blood fat, relieve brain tissue oxidative damage and hippocampal neuroinflammation damage of the diabetic model mouse, and improve learning and memory damage. The compound can be used for preparing medicines for treating or preventing cognitive impairment of diabetes mellitus.

The invention provides a preparation method of yak bone collagen peptide, a composition for promoting skeletal development and application of the composition, and relates to the technical field of health food. The preparation method comprises the following steps: carrying out ultrasonic pretreatment on yak bones, and degreasing through supercritical CO2 to obtain a degreased product; mixing the degreased product with a fishy smell removing agent to obtain a fishy smell removing product; the fishy smell removing agent is an aqueous solution of a plant extract; the plant extract is selected from at least one of amomum tsao-ko extract, turmeric extract, green tea extract or momordica grosvenori extract; the fishy smell removal product is subjected to an enzymatic hydrolysis reaction through an immobilized compound enzyme reactor, wherein the compound enzyme is prolyl endopeptidase, papain and ficin; obtaining a crude product; carrying out ultrafiltration by adopting a filter membrane with the molecular weight cut-off of 1kDa, and adsorbing through macroporous resin. The yak bone collagen peptide and the composition prepared by the invention can obviously improve the body length, promote the skeletal development and promote the secretion of growth hormone, and meet the growth requirements of children.

The invention relates to an efficient enrichment method for low-concentration bacteriophages in river and lake water bodies, which remarkably improves the recovery rate and the concentration multiple of the bacteriophages through a multi-stage synergistic technology in combination with physical interception, chemical precipitation and biological targeted adsorption. The method specifically comprises the following steps: pretreatment: removing large particles and suspended solids through gradient filtration and low-speed centrifugation; ultrafiltration concentration: adopting a hollow fiber ultrafiltration membrane with the molecular weight cut-off of 30-100 kDa, and realizing 10-50 times concentration under the pressure of 0.1-0.3 MPa; chemical precipitation strengthening: optimizing synergistic precipitation conditions of PEG and NaCl, and reducing phage inactivation in combination with low-temperature standing; specific adsorption of host bacteria: combining the host bacteria in the logarithmic phase with bacteriophage according to the volume ratio of 1: 100, and carrying out pH regulation and control elution to obtain a high-purity enriched solution. The method has the advantages that the total concentration multiple reaches 500-1000 times, and the recovery rate is gt; the activity retention rate is gt; and the method is suitable for a complex water body environment. Through a multi-technology combination strategy and targeted adsorption design, an efficient tool is provided for environmental monitoring, phage therapy and microbiological research.

The application discloses a fusion protein NGF2 with improved in-vivo half-life and application thereof, and belongs to the technical field of medical biological engineering, and comprises ABD and FGF2, and the gene and protein sequence thereof are respectively composed of the sequences shown in SEQ ID NO:1, SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:5, SEQ ID NO:6 and SEQ ID NO:7, and the complete gene and protein sequence thereof is shown in SEQ ID NO:4 and SEQ ID NO:8. The fusion protein NGF2 can keep activity for more than 7 days in an environment of 37 DEG C, and the half-life of the fusion protein in solution is prolonged. In addition, the ABD is combined with HAS to form a complex, and the total molecular weight reaches 90kDa, which is higher than the cut-off molecular weight of glomerular filtration, so that the in-vivo half-life of the fusion protein is effectively prolonged.

The invention discloses a chickpea sprout peptide. The amino acid sequence of the chickpea sprout peptide is as follows: Glu-Glu-Cys-Pro-Cys-Ala-Asn-Cys-Cys, wherein the amino acid sequence of the chickpea sprout peptide is as follows: Glu-Glu-Cys-Pro-Cys-Ala-Asn-Cys-Cys; the preparation method of the chickpea sprouting peptide comprises the following steps: step 1, sprouting chickpeas until the sprouting length is 0.5-1.5 cm, wherein the sprouting time is 12-72 hours; step 2, mixing and pulping germinated chickpeas and water according to a weight ratio of 1: 1-1: 1.2, and adjusting the pH value of the pulp to 6.5-8.0; step 3, adding neutral protease and compound flavor protease, and performing enzymolysis at the enzymolysis temperature of 50-55 DEG C for 2-3 hours; step 4, treating the enzymatic hydrolysate through an ultrafiltration membrane with the molecular weight cut-off of 5000Da under the conditions that the working pressure is 0.15-0.25 MPa and the working temperature is 20-45 DEG C, and collecting filtrate; and step 5, carrying out corrosion prevention and drying on the filtrate to obtain the chickpea sprout peptide. The chickpea sprout peptide has the effects of resisting obesity, resisting oxidation and adjusting immunity, in addition, the preparation method can achieve efficient and high-quality preparation of the chickpea sprout peptide, the chickpea sprout peptide is accurately screened, and the ineffective experiment cost is reduced.

The invention discloses a desalting nanofiltration membrane as well as a preparation method and application thereof. The preparation method of the desalting nanofiltration membrane comprises the step of compounding a polyaminopiperazine selective separation layer on the surface of a base membrane to obtain the desalting nanofiltration membrane. The molecular weight cut-off of the desalting nanofiltration membrane provided by the invention can be as low as 150Da, the cut-off rate of the desalting nanofiltration membrane to small molecular organic matters such as xylose and glucose is greater than 90%, and the cut-off rate of sodium chloride is less than 30%, namely, the desalting nanofiltration membrane shows relatively high small molecular organic matter-salt selectivity.

The invention discloses a preparation method of a crocodile polypeptide extract and a beverage, and relates to the technical field of polypeptide extraction and beverage preparation, and the preparation method comprises the following steps: pretreatment of crocodile skin; denaturation treatment: adding a NaHCO3 buffer solution, and treating under a microwave condition; performing ultrasonic pretreatment; carrying out enzymolysis reaction, namely sequentially carrying out primary enzymolysis of alkaline protease and secondary enzymolysis of compounding trypsin and neutral protease; adding composite colloid after enzyme deactivation treatment, wherein the composite colloid comprises flaxseed gum and xanthan gum; centrifuging to take supernate, and carrying out fractional separation through ultrafiltration membranes with the molecular weight cut-off of 500Da and 1000Da; and concentrating and drying to obtain polypeptide powder. According to the method, the polypeptide yield, the beverage stability and the oral bioavailability are improved; finally, the obtained polypeptide is scientifically matched with hyaluronic acid and vitamin C to prepare the beautifying beverage with the effects of remarkably improving skin stains and fine wrinkles and brightening the skin color, and the breakthrough of high-value utilization of crocodile skin resources and product function integration is realized.

The application discloses a kind of multilayer dialysis device and use method for separating landfill leachate, belong to landfill leachate processing technical field, multilayer dialysis device includes magnetic stirring module and multilayer dialysis module;Magnetic stirring module includes magnetic stirring rotor and the magnetic field control device of driving magnetic stirring rotor rotation;Multilayer dialysis module includes the experimental cylinder being set on stirring table, and multiple different diameters and coaxially arranged dialysis cylinders are arranged in experimental cylinder, and magnetic stirring rotor is arranged at the bottom of the smallest diameter dialysis cylinder;By setting multiple dialysis cylinders with different molecular weight cut-off in multilayer dialysis module, and setting magnetic stirring rotor at the bottom of the smallest diameter dialysis cylinder, not only can simultaneously process the dialysis work of multiple molecular weight organic matter and ionic landfill leachate, but also significantly improve the separation efficiency of multiple molecular weight organic matter and ions with magnetic stirring rotor, compared with single membrane technology, more separation tasks can be completed in shorter time.

The invention discloses an egg yolk globulin crude extraction method, extraction process and extraction equipment, and relates to the technical field of egg yolk globulin extraction.The process comprises the following steps that S1, egg yolk liquid is poured into a mold to be subjected to liquid nitrogen quick freezing, demolding is conducted, and the egg yolk liquid is smashed into particles; s2, mixing and stirring precooled acetone and the frozen egg yolk particles, centrifuging, and removing lipid precipitates on the upper layer; s3, adding the pre-cooled PBS, mixing, stirring and centrifuging, taking supernate, and carrying out treatment at the temperature of 0-5 DEG C; s4, slowly adding ammonium sulfate until the saturation degree is 30-40%, standing for 2 hours in an environment of 0-5 DEG C, then performing centrifugal treatment, taking precipitate, and redissolving the precipitate with PBS to obtain a redissolved solution; s5, performing ultrafiltration concentration on the reconstitution fluid by using an ultrafiltration membrane with the molecular weight cutoff of 100-200kDa; s6, carrying out ion exchange layer and hydrophobic layer chromatography treatment in sequence; and S7, carrying out pre-freezing in an environment of-80 DEG C, and then carrying out vacuum freeze-drying treatment. The method has the effect of improving the comprehensive benefit of extracting high-purity and high-activity egg yolk globulin.

The invention belongs to the technical field of separation and purification, and particularly relates to a separation and purification method for active components of wasp venom. According to the invention, only an ultrafiltration membrane method is adopted, reverse operation is carried out according to a sequence from large to small, ultrafiltration membranes with molecular weight cutoff of 30kDa, 10kDa and 3kDa are respectively used for sequentially intercepting a vespa velutina venom solution, and freeze drying is carried out, so that three active components with antifungal (candida albicans) and antibacterial (escherichia coli and staphylococcus aureus) effects are obtained. The method is simple to operate and relatively high in efficiency, purification time is greatly saved, the whole process only relates to physical separation, inactivation of active components is greatly avoided, and the method is very beneficial to process amplification.

The invention discloses a sea-buckthorn small molecule peptide and a preparation method thereof, and relates to the field of biological medicine and food processing. According to the method, sea-buckthorn pulp residues and sea-buckthorn seed residues are used as composite raw materials and are mixed and stirred to form homogenate, and then cell wall structures are destroyed through ultrasonic wall breaking treatment to release protein components; then cutting off a peptide bond under the action of compound enzymes (plant protease, neutral protease and pepsase) by adopting an ultrasonic-enzyme synergistic hydrolysis process to generate a small molecule peptide fragment; after removing impurities through centrifugal separation, purifying through an ultrafiltration membrane (the molecular weight cut-off is 1-3kDa) to obtain a small molecule peptide solution; and performing debitterizing treatment by using macroporous adsorption resin, and preparing sea-buckthorn small molecule peptide powder by using a vacuum freeze-drying technology. According to the method, through ultrasonic-enzyme synergistic interaction, multi-stage purification combination and low-temperature keep-alive processes, the yield, molecular weight uniformity and antioxidant activity of small molecular peptides are remarkably improved, and high-valued utilization of sea-buckthorn processing by-products is achieved.

The invention discloses a full-value protein biological feed production method, and relates to the technical field of protein feed production, the production method comprises the following steps: double-strain co-fermentation: cooling fermentable syrup to 38-42 DEG C, adjusting the pH value to 6.5-7.0, inoculating a mixed strain of Thermoactinomyces vulgaris and Candida utilis, fermenting for 18-24 hours under the condition that the dissolved oxygen is maintained to be 30-60%, and carrying out double-strain co-fermentation; in the process, the pH, dissolved oxygen and temperature are monitored in real time by an on-line sensor controlled by a PLC (Programmable Logic Controller), and materials are automatically supplemented; and membrane separation and concentration: enabling the fermentation liquor to pass through a PVDF (Polyvinylidene Fluoride) ultrafiltration membrane with the molecular weight cutoff of 10kDa-30kDa, and intercepting thalli and protein aggregates by a membrane concentration multiple of 5-10 to obtain a membrane concentrated solution with the protein concentration of more than or equal to 50g / L. According to the method, agricultural waste is efficiently converted into complete protein through double-bacterium synergistic fermentation, the problems that traditional single-bacterium fermentation is low in yield and unbalanced in nutrition are solved, and the protein yield is increased.

This invention relates to the field of fertilizer technology, specifically to an organic liquid fertilizer based on straw enzymatic hydrolysate and its preparation method. The method includes: pretreating corn straw with potassium hydroxide, followed by enzymatic hydrolysis with cellulase and xylanase to obtain the enzymatic supernatant; sequentially treating the supernatant with an ultrafiltration membrane with a molecular weight cutoff of 3000 Da and a nanofiltration membrane with a molecular weight cutoff of 500 Da to collect oligosaccharides with a molecular weight window of 500-3000 Da; partially stabilizing the reducing end of the oligosaccharides with sodium borohydride; pre-complexing with boric acid at pH 8.4-8.8; then sequentially adding relatively low molecular weight sodium polyglutamate, calcium chloride dihydrate aqueous solution, and ultra-high molecular weight sodium polyglutamate to construct a sequential complexation system; subsequently adding potassium nitrate and citric acid aqueous solution; and finally, after filtration at 5 μm and heat treatment at 70℃, obtaining the organic liquid fertilizer. This fertilizer has a high proportion of 500-3000 Da oligosaccharides and a low reducing sugar equivalent, inhibiting storage precipitation and browning, and improving the retention rate of extractable oligosaccharides in the soil.

The invention discloses a preparation method of dendrobium polysaccharides and cosmetic application of the dendrobium polysaccharides, and relates to the technical field of daily necessities. The preparation method of the dendrobium polysaccharide comprises the following steps: mixing dendrobium officinale powder with water to obtain a to-be-extracted solution; performing ultrasonic extraction on the to-be-extracted solution, adding a compound enzyme into the to-be-extracted solution for enzymolysis after ultrasonic extraction, and filtering the enzymatic hydrolysate by adopting an ultrafiltration membrane with the molecular weight cut-off of 5000-10000 Da after enzymolysis is finished. According to the method disclosed by the invention, the extraction effect of the dendrobium polysaccharides can be remarkably improved and the content of the dendrobium polysaccharides can be increased in a manner of ultrasonic extraction, enzymolysis and ultrafiltration membrane filtration, and the prepared dendrobium polysaccharides are relatively high in content and relatively small in molecular weight. The ultra-low molecular dendrobium polysaccharide (the molecular weight is generally less than 10kDa) is selected as a component of the anti-oxidation and anti-wrinkle composition, so that the transdermal absorption efficiency and bioavailability of the anti-oxidation and anti-wrinkle composition can be remarkably improved. The antioxidant and anti-wrinkle composition can be widely applied to preparation of skin care products or cosmetics.

The invention discloses an improved loading method of a nano-drug carrier, which comprises the following steps: adding a carrier of recombinant human heavy-chain ferritin or a derivative thereof into a high-concentration urea solution, mixing and reacting to depolymerize a shell of the recombinant human heavy-chain ferritin; adding a medicine, mixing and incubating; and diluting a reaction solution obtained by incubation into a low-concentration urea solution by using a Tris buffer solution, reacting for 8-15 hours to re-polymerize the recombinant human heavy chain ferritin shell, and finally changing the solution by using a membrane bag with the molecular weight cutoff of 50 KD through the Tris buffer solution to obtain the loaded ferritin drug composite particles. According to the preparation method provided by the invention, the effect of obviously improving the protein recovery rate and the drug loading capacity is achieved by providing a preparation method of replacing liquid after dilution and then standing and optimizing the drug-mass ratio, the protein recovery rate can reach 100%, and the drug loading capacity can reach 186 mu g / mL.

The invention relates to application of a high-selectivity nanofiltration membrane regulated and controlled by chitosan hydrogel to separation of salt ions and perfluorinated compounds in a mineral salt solution. The invention provides application of a high-selectivity nanofiltration membrane regulated and controlled by chitosan hydrogel to separation of salt ions and perfluorinated compounds in a mineral salt solution. The high-selectivity nanofiltration membrane comprises a base membrane, and a hydrogel layer and a polyamide layer which are respectively arranged on the surface of the base membrane. Experiments prove that when natural water is treated, the total salt rejection rate is reduced along with the increase of the concentration of the middle layer, the conductivity is reduced under the combined action of the size screening effect of the cut-off molecular weight and electronegative electrostatic repulsion, and the modified membrane can permeate more mineral elements.

The present invention relates to a method for preparing a composite nanofiltration membrane and a composite nanofiltration membrane prepared thereby. The method for preparing the composite nanofiltration membrane comprises the following steps: preparing a polymer solution as a casting liquid, solidifying the casting liquid on a reinforcing material to form a base membrane; then sequentially contacting with an aqueous solution containing an amine compound, a silane coupling agent and a biomass acid, and an oil phase solution containing a polyacid chloride to form a functional layer; and obtaining a composite nanofiltration membrane after post-treatment and drying. In the preparation method of the present invention, base membranes with different surface average pore sizes are obtained by adjusting the concentration of the polymer in the casting liquid; by adding a silane coupling agent and a biomass acid to the aqueous solution to eliminate other reaction variable factors, the interfacial polymerization reaction is only affected by the average pore size of the base membrane, and accordingly, composite nanofiltration membranes with functional layers with different surface average pore sizes are obtained, thereby having different maximum retention molecular weights.

The invention discloses a preparation method of shiitake mushroom foot umami peptide based on an enzyme membrane reactor. The preparation method comprises the following steps: extracting shiitake mushroom foot protein; the shiitake mushroom foot umami peptide is prepared based on enzymolysis of an enzyme membrane reactor, and the molecular weight cutoff of an ultrafiltration membrane configured in the enzyme membrane reactor is 5-30 kDa, preferably 30 kDa. The invention also discloses five shiitake mushroom foot umami peptide products screened from the prepared shiitake mushroom foot umami peptide. The mushroom foot umami peptide is prepared by using the enzyme membrane reactor, and the protein conversion rate is improved, so that the yield of the mushroom foot umami peptide is improved. Wherein the shiitake mushroom foot umami peptide prepared by the enzyme membrane reactor with the ultrafiltration membrane molecular weight cutoff of 30 kDa has higher umami strength and relatively small bitter taste. Five shiitake mushroom foot umami peptide products are screened from the prepared shiitake mushroom foot umami peptides, and the umami threshold value of the shiitake mushroom foot umami peptide products is low and ranges from 0.023 mM to 0.375 mM; the fresh taste score is high (electronic tongue score), and is 16.66-18.11.

The application provides a layer-by-layer self-assembly nanofiltration membrane, a preparation method and application thereof. The layer-by-layer self-assembly nanofiltration membrane comprises a base film and a self-assembly coating layer formed on the base film, wherein the self-assembly coating layer comprises at least a starting alternating coating layer and a separation alternating coating layer; the molecular weight cut-off of the base film is not less than 500 kDa; the starting alternating coating layer is alternately assembled by a high-molecular-weight cationic polyelectrolyte layer and an anionic polyelectrolyte layer; the separation alternating coating layer is alternately assembled by a low-molecular-weight cationic polyelectrolyte layer and an anionic polyelectrolyte layer; the starting alternating coating layer is formed on the base film, and the high-molecular-weight cationic polyelectrolyte layer in the starting alternating coating layer adopts a cationic polyelectrolyte with a number-average molecular weight of not less than 500 kDa; and the low-molecular-weight cationic polyelectrolyte layer in the separation alternating coating layer adopts a cationic polyelectrolyte with a number-average molecular weight of not more than 100 kDa. The layer-by-layer self-assembly nanofiltration membrane has more excellent permeability and micro-pollutant rejection rate.

The invention relates to the technical field of cell culture, in particular to nano liver stem cell peptide as well as a preparation method and application thereof. The preparation method of the nano liver stem cell peptide comprises the following steps: (1) mixing induced pluripotent stem cells with a first induced differentiation culture medium, and culturing for 3-5 days to obtain an intermediate cell 1; (2) inoculating the intermediate cell 1 into a second induced differentiation culture medium, and culturing for 3-5 days to obtain an intermediate cell 2; and (3) inoculating the intermediate cell 2 into a third induced differentiation culture medium, and culturing for 3-5 days to obtain the liver stem cell, and (4) after the liver stem cells are subjected to ultrafiltration, taking substances of which the molecular weight cutoff is less than or equal to 50kDa, centrifuging, taking precipitates, and drying to obtain the liver stem cell peptide. The liver stem cell peptide prepared by the method has the particle size of 1-20nm, can target the liver, has a good effect in treatment of liver injury, and does not generate drug resistance.

The invention discloses a preparation method and application of a fluorescent polymer dot with adjustable chargeability. Using natural polymer sodium alginate SA as the main carbon source and introducing o-phenylenediamine oPDA as an auxiliary agent, carbonized polymer dots SAPD-CPDs are synthesized by a hydrothermal method. SA and oPDA are mixed in water and sonicated until completely dissolved, then the pH value of the solution is adjusted to 4 with hydrochloric acid and sodium hydroxide solutions, sealed in the polytetrafluoroethylene liner of a reaction kettle, and placed in an oven at 160 °C for reaction for 10 h. It is filtered through a 0.22 μm mixed cellulose filter, dialyzed for 24 h with a dialysis bag having a molecular weight cut-off of 500 Da, vacuum concentrated, and then freeze-dried to obtain a solid powder. The carbon dots retain the characteristics of the sodium alginate polymer chain and can form a stable luminescent film with chitosan due to physical adsorption.

The application discloses a dandelion extract capable of neutralizing bacterial toxins and application thereof. The dandelion extract is mainly prepared by the following method: fresh dandelion juice is squeezed, the juice is collected, the juice is centrifuged, the supernatant is collected, the supernatant is ultra-filtered, and components capable of passing through a filter membrane with a molecular weight cut-off of 100 kD and incapable of passing through a filter membrane with a molecular weight cut-off of 3 kD are collected, namely the dandelion extract. The dandelion extract obtained by the application is natural in composition, free of toxic side effects and high in biological activity. Experimental evidence shows that the dandelion extract can protect host cells from attack by directly and specifically combining with toxins, effectively neutralizes the toxicity of bacterial toxins, and has effective prevention and treatment effects on diseases such as systemic bacterial infection, wound infection and bacterial pneumonia. Therefore, the dandelion extract can be used as a new type of anti-microbial and anti-infection functional material and applied to the fields of functional food, health products, medicines or functional cosmetics.

The invention discloses a walnut source DPP-IV inhibitory peptide as well as a preparation and screening method and application thereof. The walnut source DPP-IV inhibitory peptide comprises FPAG and / or LPSYQPTP, the preparation and screening method comprises the following steps: (1) adding walnut protein powder into deionized water, and fully dissolving to obtain a walnut protein solution; (2) adding hydrolyzed compound protease into the walnut protein solution for enzymolysis to obtain walnut protein hydrolysate freeze-dried powder; (3) re-suspending the walnut protein hydrolysate freeze-dried powder in deionized water, and performing ultrafiltration separation by using an ultrafiltration membrane with the molecular weight cutoff of 1kDa to obtain a component F1; step (4), performing peptide fragment sequence identification on the obtained F1 component through peptidomics; and step (5), screening from peptide fragment sequences obtained by identification through a bioinformatics technology. The walnut source DPP-IV inhibitory peptide screened by the invention can be used for preparing a medicine or food with a DPP-IV inhibition function, so that the problems that the existing walnut source DPP-IV inhibitor has many side effects and the like are solved.

This invention belongs to the field of cosmetic raw material technology, specifically relating to a skincare product raw material containing peony root bark extract and its preparation method. In the skincare product raw material containing peony root bark extract provided by this invention, the volume ratio of peony root bark concentrate: 1,3-butanediol:water is 0.9:6:3.1. The peony root bark concentrate is first prepared using a full-process membrane separation technology. Specifically, the aqueous extract of peony root bark is first clarified and filtered using a ceramic membrane with a pore size of 1μm. Then, it undergoes three-stage retention separation using ultrafiltration membranes with molecular weight cutoffs of 10000 Da, 5000 Da, and 3000 Da. Finally, a fourth-stage retention separation is performed using a nanofiltration membrane with a molecular weight cutoff of 500 Da, followed by concentration via reverse osmosis. The cosmetic raw material prepared by this invention is rich in membrane-purified active ingredients of peony root bark, is green, safe, and non-irritating, and has multiple effects such as moisturizing, whitening, anti-inflammatory, antibacterial, acne-reducing, and oil-controlling properties.

The invention belongs to the technical field of high polymer materials, and particularly relates to a polyimide composite film as well as a preparation method and application thereof. The polyimide composite film is prepared from composite slurry containing polyimide, nanocrystalline cellulose and a polar aprotic solvent, the mass fraction of the nanocrystalline cellulose is 0.3%-0.7%, the mass fraction of the polyimide is 10%-20%, and the mass fraction of the polar aprotic solvent is 79.3%-89.7%. The preparation method comprises the following steps: preparing the nanocrystalline cellulose, synthesizing a polyamide acid solution, mixing the nanocrystalline cellulose and the polyamide acid solution to prepare composite slurry, and finally preparing the composite membrane by an immersion precipitation phase inversion method. The composite membrane has precise molecular weight cut-off, and meanwhile, the hydrophilicity, the mechanical strength and the anti-pollution performance are remarkably improved. The composite membrane can be directly used for intercepting macromolecular pollutants in sewage treatment or used as a supporting layer of a composite nanofiltration membrane, and the problem that the performance of a traditional separation membrane material is difficult to consider is solved.

The invention discloses a composite nanofiltration membrane as well as a preparation method and application thereof. The preparation method of the composite nanofiltration membrane comprises the following steps: (1) dissolving a soluble polymer in a solvent to obtain a membrane casting solution; coating the membrane casting solution to form a membrane, and then immersing the membrane in a non-solvent to convert the phase of the membrane into a solid membrane; (2) immersing the solid membrane in a water phase solution for first treatment to obtain a primary composite nanofiltration membrane; wherein a water-phase monomer in the water-phase solution comprises a component A and a component B; (3) immersing the obtained primary composite nanofiltration membrane in an oil phase solution for second treatment; then carrying out heat treatment to obtain a composite nanofiltration membrane; wherein an oil phase monomer in the oil phase solution is selected from at least one of phenyl acyl chloride. The composite nanofiltration membrane is prepared by adopting an interfacial polymerization method, and high-temperature-resistant nanofiltration membranes with different molecular weight cut-off can be prepared.

The invention discloses a treatment method suitable for livestock breeding wastewater, and relates to the field of wastewater treatment.The wastewater sequentially passes through a pretreatment unit, a biochemical treatment unit, an advanced treatment unit and a solid waste resourceful treatment unit, and the pretreatment unit comprises solid-liquid separation, water quality adjustment and preliminary flocculation precipitation; the biochemical treatment unit comprises anaerobic treatment and a two-stage A / O process. Through an integrated process of pretreatment, two-stage A / O biochemical treatment, hollow fiber nanofiltration and contact oxidation, synergistic deep removal of organic matters, nitrogen, phosphorus and chromaticity in the breeding wastewater is realized, the effluent quality is excellent and stable, the impact load resistance of the system is high, energy and resource recovery is realized through UASB biogas production and sludge composting, and the method is suitable for industrial production. Optimized membrane molecular weight cutoff and automatic control ensure long-term stable operation of a membrane system, membrane concentrated water backflow avoids secondary pollution, and a set of efficient and recycling complete solution is formed.