914 results about "Enzyme catalysis" patented technology

The invention discloses silk fibroin composite gel and a preparation method thereof, and relates to the technical field of tissue filling materials. The preparation method of the silk fibroin composite gel comprises the following steps: preparing silk fibroin and carrying out amination modification on the silk fibroin to obtain aminated silk fibroin; carrying out dynamic cross-linking on the aminated silk fibroin and the oxidized sodium alginate through a Schiff base bond by adopting an enzyme catalysis cross-linking process to obtain a dynamic cross-linked network solution; adding a temperature-sensitive component into the dynamic cross-linked network solution, and uniformly mixing to obtain a temperature-sensitive-dynamic dual-network pre-gel solution with temperature responsiveness; loading the active component into the temperature-sensitive-dynamic dual-network pregel solution to obtain a composite gel solution; incubating the composite gel solution to obtain primary gel; after disulfide bonds are introduced into the primary gel, cross-linking strengthening and sterilization are carried out, and the silk fibroin composite gel is obtained. Through temperature-sensitive-dynamic dual-network design, active components and disulfide bonds are introduced to strengthen crosslinking, and the problems that traditional injectable gel is irreversible, single in function, prone to collapse after being filled and the like are systematically solved.

The invention discloses a high-performance carbonyl reductase mutant and application thereof in synthesis of a series of chiral alcohols. The high-performance carbonyl reductase mutant is obtained by performing the following mutations on an amino acid sequence as shown in SEQ ID NO.2: the 69th alanine mutates into any one of lysine, leucine, aspartic acid or asparagine, and the 69th alanine mutates into any one of lysine, leucine, aspartic acid or asparagine; and / or the 100th glycine is mutated into any one of glutamic acid, serine, lysine or asparagine. Compared with a wild type enzyme, the thermal stability and the catalytic activity of the obtained mutant are remarkably improved, particularly, single point mutants Mut-A69N, Mut-G100E and Mut-G100N and a combined mutant Mut-A69N-G100N show excellent relative enzyme activity, thermal stability and substrate tolerance. The mutant has high catalytic activity and stability to various chiral alcohols, and the contradiction that the traditional carbonyl reductase is easy to inactivate at high temperature and the catalytic efficiency is difficult to achieve at the same time is solved. The invention provides an efficient and stable enzyme catalysis tool for green biological preparation of chiral drug intermediates.

The invention relates to a silk fibroin biological material with high beta-fold content and a preparation method thereof, and belongs to the technical field of biological extraction. The method comprises the following steps: preparing a regenerated silk fibroin solution; adding an enzyme catalytic promoter and an enzyme into the regenerated silk fibroin solution for incubation; the enzyme catalysis auxiliary agent is selected from one or more of a metal ion catalyst, a zwitterionic surfactant, a functionalized ionic liquid and a calcium phosphate nano-cluster; and centrifuging, cleaning and drying the obtained product to obtain the silk fibroin biological material with high beta-fold content. The silk fibroin material has higher beta-folding amount through primary structure modification, the space structure is more crystallized, and the amino acid sequence is more regular and ordered. The silk fibroin material provided by the invention has excellent mechanical properties, efficiency and yield, and is a biological protein material with great development potential.

The invention belongs to the technical field of separation of products for synthesizing antibiotics by an enzymic method, and particularly relates to a method for separating and recycling an amoxicillin product synthesized by a one-step method based on catalysis of kluyveromyces citricacidophilus beta subunit G385 mutant penicillin acylase. An immobilized penicillin acylase mutant is used for catalyzing penicillin potassium to synthesize amoxicillin in one step, a set of method for separating amoxicillin and phenylacetic acid is developed for an obtained reaction mixture, and the technical scheme mainly comprises the following steps: firstly, separating the immobilized penicillin acylase mutant from a reaction solution through filtration; then, amoxicillin is separated out through crystallization; and then crystallizing, separating and recovering phenylacetic acid through toluene extraction, back extraction and the like. According to the separation method, the amoxicillin can be rapidly and efficiently separated, the yield of the amoxicillin is relatively high, and the average crystallization rate reaches 93.22%; meanwhile, the separation and recovery effects of phenylacetic acid are good; and the extraction agent toluene can be recycled.

The invention provides a chiral resolution method and application of a 3-aryl substituted glutaric acid monoester compound, and the method comprises the following steps: taking a substance as shown in a formula I as a starting raw material, and carrying out alcoholysis to obtain a racemic intermediate as shown in a formula IV; and splitting the intermediate shown in the formula IV, and then dissociating to obtain the compound shown in the formula III, which has a single spatial configuration and an ee value of more than 99%. A cyclic anhydride substrate with a symmetrical structure is used and reacts with alcohol to obtain racemic 3-aryl substituted glutaric acid monoester, a target configuration with high chiral purity is obtained by screening some resolution reagents and solvents and performing salifying resolution on the 3-aryl substituted glutaric acid monoester, the operation is simple, the resolution reagents are easily available in the market and can be recycled, and the method is suitable for industrial production. The method has the advantages that an expensive chiral catalyst or a harsh enzyme catalysis condition is avoided, the reaction cost is reduced, amplified production is facilitated, the ee value of a target configuration can be increased to 99% or above, and the method is an economic and environment-friendly technical route which is simple in post-treatment and convenient for amplified production.

The present disclosure describes a Pseudococcus preparation and a preparation method and application thereof, the Pseudococcus preparation comprises an active ingredient, the active ingredient comprises a specific pro-inflammatory regression mediator (SPMs) and a pro-inflammatory regression mediator (PRMs), the specific proinflammatory regression medium and the proinflammatory regression medium are generated by catalyzing unsaturated fatty acid synthesized by micrococcus by own enzyme. According to the invention, the invention can provide the micrococcus preparation containing the specific proinflammatory regression medium and the proinflammatory regression medium as well as the preparation method and the application of the micrococcus preparation.

The invention discloses a molecular modification design method for improving the catalytic activity and the thermal stability of citrobacter vinegaticus-derived hyaluronidase and expression application of the citrobacter vinegaticus-derived hyaluronidase. The interaction of citrobacter vinegaticus hyaluronidase active pocket amino acid residues and hyaluronate tetrasaccharide molecules is visually explored through Pymol, conservative analysis of pocket amino acid evolution is carried out through Consurf, and rational design is carried out through policies of FoldX for calculating enzyme-substrate binding free energy, so that the hyaluronidase catalytic activity is improved. A mutant with significantly improved enzyme activity is obtained through screening, and the thermal stability of the enzyme is further improved through PROSS design and an analysis strategy of mutation site amino acid evolution conservative property and position. According to the invention, the sequence, structure and function of hyaluronidase are deeply studied, and hyaluronidase is mutated from two aspects of stabilizing a catalytic structure and promoting a catalytic reaction, so that a high-activity enzyme with higher application value in industrial production is obtained.

The invention belongs to the technical field of engineered probiotics, and particularly relates to engineered probiotics for radiosensitization and tumor metabolism regulation as well as a preparation method and application of the engineered probiotics. The engineering probiotics comprise probiotics and core-shell type metal nanoparticles which are loaded on the probiotics and are synthesized through a biological directional mineralization effect; the core of the core-shell type metal nanoparticle is a palladium element, and the outer layer of the core-shell type metal nanoparticle is a palladium element and a gold element. The engineering probiotics provided by the invention have excellent enzyme catalysis performance and can target and retain in tumor sites, and through the synergistic effect of all components in the engineering probiotics, adenosine metabolism is effectively inhibited, secretion of pro-inflammatory cytokines is enhanced, tumor microenvironment is promoted to be converted into an inflammatory state, up-regulation of immune checkpoints is inhibited, and the immune checkpoints are inhibited. And T cells are inhibited from being transformed into depletion phenotype and transformed into effect type from depletion type. After the SBRT and the immune checkpoint inhibitor are combined for use, the growth of tumors can be effectively inhibited, and the effect of enhancing immune radiotherapy is achieved.

The invention discloses an endoglucanase truncated mutant and an application of the endoglucanase truncated mutant. According to the invention, based on endoglucanase BsEGL from bacillus subtilis DLG, a truncated mutant is constructed by deleting a carbohydrate binding domain (CBM) of the endoglucanase BsEGL, and the truncated mutant is named as BsEGL [delta] CBM. Compared with BsEGL, the truncated mutant BsEGL delta CBM has the advantages that the thermal stability, the pH stability, the organic solvent tolerance and the like are remarkably improved, and the activity of degrading phosphoric acid expanded cellulose and corncob xylan is obtained. In addition, the enzymatic activity of the truncated mutant BsEGL delta CBM is remarkably improved by 6.41%, and the catalytic efficiency is remarkably improved. Due to the characteristics, the mutant can be suitable for industrial processes such as feed processing, papermaking, biological energy sources, spinning and food brewing, and is particularly suitable for enzyme catalytic reaction under extreme environments such as high temperature and low pH. The invention provides an enzyme preparation tool with excellent performance for efficient degradation of cellulose biomass, and has important application value.

The invention belongs to the technical field of biology, and particularly relates to a method for producing xylitol through two-step enzyme catalysis of hemicellulose hydrolysate, and the method comprises the following steps: taking hemicellulose hydrolysate as a raw material, adding arabinose dehydrogenase, NADH oxidase and coenzyme NADH, and carrying out first-step fermentation until no L-arabinose residue exists in fermentation liquor to obtain fermentation reaction liquor I; and adding xylose reductase and glucose dehydrogenase into the fermentation reaction liquid I, and carrying out second-step fermentation to obtain a fermentation product containing xylitol. According to the two-step enzyme catalysis method provided by the invention, xylitol is prepared, and high-purity xylose does not need to be used as a raw material; according to the present invention, the cheap hemicellulose hydrolysate can be directly adopted as the raw material, the xylose conversion rate and the xylitol yield can exceed 99%, the impurity arabitol content in the product is low, the other impurity saccharic acid is easy to separate, and the problems of complex process, large separation difficulty and high cost in the xylitol refining process are successfully solved.

The invention provides a method for preparing high-purity phosphatidylserine by a batch enzyme catalysis method based on dynamic choline removal, and belongs to the technical field of enzymatic reaction. According to the method disclosed by the invention, in a reaction system for preparing phosphatidylserine, a byproduct choline is selectively adsorbed by adopting resin. Choline in a reaction system is removed in real time through the integrated adsorption separation module, the enzyme inhibition problem is solved, and meanwhile, the PC conversion rate is larger than or equal to 98% and the PS purity is larger than or equal to 96% in combination with the immobilized enzyme circulation technology; the enzyme can be reused for more than or equal to 20 times (activity retention is more than or equal to 90%); and the choline residual concentration is less than or equal to 0.5 mM (an inhibition threshold value or less).

The application discloses a galactosyltransferase mutant and application thereof in preparation of flavonoid compounds, and belongs to the technical field of enzymology. The application provides a UDP-galactosyltransferase mutant, which is obtained by site-directed mutation of one amino acid in the amino acid sequence of wild-type galactosyltransferase VcUFGT into alanine (A). The effects of a series of mutants H82A, V139A, G141A, P186A, N245A, V282A and S307A are verified in the examples, the mutants can perform enzyme catalysis reaction with quercetin and UDP-galactoside as substrates, and generate flavonoid compound hyperoside, and the specific enzyme activity of the mutants is more than 1.5 times that of the wild type, thereby providing an effective application basis for biosynthesis of flavonoid compounds.

The invention provides a carbonyl reductase mutant and application thereof in preparation of chiral alcohol compounds, and belongs to the technical field of gene engineering and enzyme catalysis. According to the invention, on the basis of the wild carbonyl reductase, the mutant with activity obviously superior to that of the wild carbonyl reductase is obtained through specific mutation, the selectivity and stability of the enzyme are improved, and the mutant has a wide application prospect in catalytic synthesis of chiral alcohol compounds.

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

The invention provides a saccharomyces cerevisiae engineering strain HYB05 capable of releasing astaxanthin in a controllable self-splitting manner. The saccharomyces cerevisiae engineering strain HYB05 is constructed by taking a basic strain for producing astaxanthin as a starting strain, introducing a coding sequence comprising cell wall lyase Lyc, a coding sequence of a signal peptide mutant F8A and a recombinant nucleic acid construct for expressing a regulatory element, and knocking out an SSD1 gene to relieve a translation inhibition effect. The cell wall lyase Lyc is found and disclosed by the inventor for the first time, and the amino acid sequence is shown as SEQ ID NO: 6; the amino acid sequence of the signal peptide mutant F8A is as shown in SEQ ID NO: 8. According to the engineering strain HYB05, by introducing the recombinant nucleic acid construct, the activation of the catalytic activity of cell wall lyase under specific conditions is realized, so that the cell wall of the saccharomyces cerevisiae is broken, and the astaxanthin synthesized by the saccharomyces cerevisiae is released. Compared with the prior art, the astaxanthin is produced through fermentation of the strain, the extraction steps are simplified, extraction of the astaxanthin in the yeast is achieved to the maximum extent, the yield of the astaxanthin is remarkably increased, and the technical effect is remarkable.

The invention relates to the technical field of mineral materials and nano-enzyme catalysis, in particular to an iron-containing layered silicate mineral nano-enzyme as well as a preparation method and application thereof. The preparation method comprises the following steps: carrying out ball milling on the iron-containing layered silicate mineral, carrying out centrifugal washing, and drying to obtain the iron-containing layered silicate mineral nano-enzyme. According to the method, silicate minerals with a layered structure and rich iron content are adopted as raw materials, the ball-milled layered silicate mineral nano-enzyme is successfully prepared through a ball milling method, the crystallinity of the minerals is reduced, the surface acidity of the minerals is improved, and low-spin iron is generated, so that the affinity of the ball-milled minerals to H2O2 is enhanced; h2O2 is catalyzed to generate singlet oxygen and superoxide free radicals, so that the peroxidase-like activity of the ball-milled minerals is improved. The enzyme-like activity is improved by 10 times, high catalytic activity can still be kept under the neutral condition, and the method can be used for colorimetric sensing and antibacterial application of small biological molecules such as glucose, hydrogen peroxide and glutathione.

The invention provides a plasmid, an alpha-ketoglutaric acid engineering strain and a construction method and application of the alpha-ketoglutaric acid engineering strain, the strain is obtained by adopting a directional transformation method, transcriptional levels of katE, katG, sodB and grxA genes are up-regulated, a catR gene and a katA gene are heterologously expressed, a high-copy plasmid pETKG is carried, and the plasmid simultaneously expresses L-glutamate oxidase LGOX genes from Streptomyces sp and Chain A; the strain self-synthesized catalase eliminates H2O2 generated in the process of producing alpha-ketoglutaric acid through enzyme catalysis, engineering bacteria of L-glutamate oxidase LGOX expressed by pETKG plasmids are used for performing whole-cell catalysis on L-sodium glutamate to synthesize alpha-ketoglutaric acid, and the engineering strain is a high-level engineering strain capable of industrially and stably producing alpha-ketoglutaric acid.

The invention discloses a method for synthesizing ceramide NP through two-step enzyme catalysis, which comprises the following steps of: firstly, adding lipase into vegetable oil to catalyze and combine fatty acid to decompose into free fatty acid, and centrifuging to remove the lipase; a small amount of phytosphingosine is added into the hydrolyzed vegetable oil, the raw material vegetable oil is used as a solvent or a squalane system solvent for incubation, and then immobilized lipase is added for catalytic synthesis of ceramide. The invention establishes a two-enzyme method for efficiently synthesizing the ceramide NP compound, and the process is natural, environment-friendly and non-toxic. The reaction conditions are optimized through response surface analysis, meanwhile, the immobilized lipase shows excellent cycle performance, and the method is easy to operate, environmentally friendly, green and economical and has wide application prospects in the fields of cosmetics, health care products, biological medicine and the like.

The invention discloses an enzyme catalytic synthesis method of a luliconazole chiral intermediate, which comprises the following steps: adding a recombinant escherichia coli wet cell for expressing alcohol dehydrogenase, a recombinant escherichia coli wet cell for expressing formate dehydrogenase, a buffer solution, a substrate, a cosolvent, ammonium formate and a coenzyme into a reaction container, reacting at 25-35 DEG C for 2-24 hours, extracting, separating, and carrying out rotary evaporation, thereby obtaining the luliconazole chiral intermediate. The luliconazole chiral intermediate is obtained; the substrate is 2, 2 ', 4'-trichloroacetophenone; the alcohol dehydrogenase is a mutant of AKR3. The method is mild in reaction condition, environmentally friendly, high in regioselectivity and stereoselectivity, high in conversion rate, high in chiral purity, small in enzyme dosage, low in preparation cost and suitable for industrial production.

The invention relates to the technical field of food processing, in particular to a chicken premade dish and a preparation method thereof. By innovatively integrating a laccase-chequer-shaped indocalamus leaf cross-linking system and a double-frequency ultrasonic pretreatment process, the water retention, bacteriostasis and flavor regulation performance of the chicken premade dish can be synchronously improved, and the effect cannot be replaced by other enzymes such as papain; besides, double-frequency ultrasonic pretreatment is adopted, dynamic balance of deep penetration-surface tenderization is achieved through frequency alternation, and compared with single-frequency or traditional soaking, the method can better cooperate with laccase catalysis to directionally cross-link the preservative, and the effects of water retention, bacteriostasis and flavor regulation and control are achieved.

The invention belongs to the technical field of drug delivery systems, and discloses a two-dimensional vermiculite-based drug delivery system and a preparation method and application thereof. The preparation method comprises the following steps: carrying out ion exchange on expanded vermiculite, NaCl and LiCl, stripping by using a mechanical stripping sheet, centrifuging to obtain a two-dimensional vermiculite nanosheet dispersion liquid, dispersing a drug in the two-dimensional vermiculite nanosheet dispersion liquid, and forming a film to obtain the two-dimensional vermiculite-based drug delivery unit. The drug is synergistically loaded between layers and on the surface of the vermiculite; rich hydroxyl groups and interlayer cations on the end surface of the vermiculite interact with the drug, so that the drug release time is relatively long; the vermiculite-based drug delivery system can realize gradient order release of drugs according to a sequence from the surface to the interlayer through pH response of an affected part. Meanwhile, the vermiculite-based drug delivery system provides an antibacterial effect through enzyme-like catalytic activity, and avoids the problems of abuse of antibiotics and drug resistance.

The present application relates to a pyridoxal kinase mutant, a recombinant expression vector and a microbial cell and their applications, and belongs to the technical field of biological catalysis. In order to solve the problem of low product concentration in existing enzyme catalysis, a pyridoxal kinase mutant is provided, the amino acid sequence is selected from the amino acid sequence shown in SEQ ID NO. 1, the lysine at position 229 is mutated to alanine, phenylalanine, methionine, arginine, threonine, histidine, serine, tyrosine, valine, leucine, isoleucine, proline, asparagine, aspartic acid or glutamic acid; the pyridoxal kinase mutant is used for catalyzing pyridoxal to synthesize pyridoxal phosphate, and a recombinant expression vector and a microbial cell can be further formed. The present application has good enzyme activity, high product conversion rate, high concentration of pyridoxal phosphate obtained, and the concentration of the product catalyzed by the wild-type pyridoxal kinase to phosphorylate pyridoxal is obviously improved.

Provided is a method for preparing purine nucleoside. The preparation method comprises catalyzing a uridine substrate and a substrate base by using a pyrimidine nucleoside phosphorylase and a purine nucleoside phosphorylase, and preparing and obtaining purine nucleoside. The uridine substrate comprises uridine, 2'-deoxyuridine or 2'-amino-2'-deoxyuridine, and the substrate base comprises a purine compound, wherein on the purine compound, R1 comprises -NH 2,-OCH 3 or -Cl, and R2 comprises -NH 2, -F or -Cl. The preparation method can solve the problem of low yield in the preparation of nucleoside compounds in the prior art, and is suitable for the field of enzymatic catalysis.

The invention belongs to the technical field of enzyme catalysis, and particularly relates to a dehydrogenase mutant, a gene, an engineering bacterium and application, the dehydrogenase mutant is obtained through mutation of original dehydrogenase, the sequence of the original dehydrogenase is SEQ ID NO.1, and the mutation mode is that the 344 site is mutated from A to W, K, F, S or N, or the 130 site is mutated from H to T, W or F; the dehydrogenase mutation diagram provided by the invention has higher conversion rate, stronger specificity and faster reaction speed.

The invention relates to a method for preparing (S)-chiral amine through asymmetric catalysis of imine reductase, and belongs to the technical field of biological pharmacy. Comprising the following steps that imine reductase catalyzes imine to be subjected to a reductive hydrogenation reaction under the conditions of coenzyme and a coenzyme regeneration system, and the (S)-chiral amine compound is generated. According to the method, imine reductase is utilized to catalyze imine asymmetric reduction to prepare the innovative drug (S)-chiral amine compound, and compared with a traditional chemical synthesis method, the method has the advantages of being high in reaction efficiency, good in stereoselectivity, mild in reaction condition, environmentally friendly and the like, and is a method meeting the green production requirement.

The invention relates to the technical field of organic synthesis, in particular to a method for constructing Orforglipron tetrahydropyran ring chirality through enzyme catalysis, which comprises the following steps: step S1, taking SM1 as a raw material, and carrying out hydrolysis resolution in a solvent, a buffer salt system and enzyme catalysis to obtain a chiral pure intermediate INT-1; step S2; performing ring closing on the INT-1 through Grignard reaction to synthesize a lactone intermediate; s3, carrying out Diball-H reduction, quenching, dichloromethane extraction and anhydrous sodium sulfate drying on the INT-4, and then reducing the INT-4 by using triethyl silane to obtain an intermediate INT3; step S4, coupling the INT-3 in the presence of a catalyst and a ligand to obtain an intermediate INT-4; step S5, carrying out deprotection and salification on the INT-4 to obtain an intermediate INT5; s6, closing an indole ring from INT5 to obtain a compound of which the general formula is A; chirality is constructed through enzyme catalysis, isomer impurities do not need to be split and separated through SFC when the chirality is constructed, the loss is reduced, the yield is increased, and a target product is obtained with high chiral selectivity; meanwhile, the cost is relatively reduced, and the cost is saved.

The invention discloses a preparation method and application of an ovotransferrin oligomer with an immunomodulatory effect, and a function enhanced nano oligomer is constructed through an enzymatic crosslinking and dynamic hot pressing synergistic treatment technology. The preparation method comprises the following specific steps: preparing an ovotransferrin solution, adjusting the pH value to 1.5-2.0, carrying out high-pressure homogenization and double-frequency ultrasonic treatment after pre-denaturation, adding TG enzyme to catalyze, crosslink and induce controllable aggregation, and finally freeze-drying to obtain oligomer powder, the oligomer is of a nano-scale spherical structure, the particle size is 50-200nm, the solubility is good, and the immunoregulation function is remarkably enhanced. Comprising the steps of promoting dendritic cells to secrete immune factors, prolonging the survival time of nematodes under bacterial infection and improving the immune function of immunosuppressive mice. The method disclosed by the invention is simple in process, green and environment-friendly, suitable for the fields of functional health-care products, pharmaceutical preparations, formula foods with special medical purposes and the like, and wide in application prospect.

The invention discloses an enzyme catalysis preparation method of a milobalin intermediate. According to the method, racemization 3-ethyl bicyclo [3.2. 0] hept-3-ene-6-ketone is used as a substrate, specific ketoreductase is used as a catalyst, (1S, 5R)-3-ethyl bicyclo [3.2. 0] hept-3-ene-6-ketone is selectively reduced into (1S, 5R)-3-ethyl bicyclo [3.2. 0] hept-3-ene-6-alcohol, and a target compound milobalin intermediate (1R, 5S)-3-ethyl bicyclo [3.2. 0] hept-3-ene-6-ketone is reserved. According to the method disclosed by the invention, only one enzyme is used, the concentration of a conversion substrate can reach 200g / L, the yield can reach 47.4%, the ee value can reach 99.8%, the operation is simple, the resolution efficiency is high, the selectivity is good, and the method can be used for industrial production.

The invention relates to the technical field of prebiotics preparation, and discloses a preparation method of prebiotics applied to reproduced areca catechu, and the preparation method comprises the following steps: carrying out enzyme catalysis reaction on sucrose by adopting fructosyl transferase to prepare fructo-oligosaccharide; according to the method, beta-galactosidase is adopted to carry out enzyme catalysis reaction on lactose, so that galactooligosaccharide is prepared; respectively carrying out decoloration, ion exchange, nanofiltration concentration and spray drying on the candy oligosaccharide and the galactooligosaccharide to obtain powder; the method comprises the following steps: mixing fructo-oligosaccharide powder and galactooligosaccharide powder according to a ratio, and uniformly distributing the mixture in a reproduced areca-nut matrix by adopting a spray-drying blending or low-temperature vacuum mixing mode to form a functional reproduced areca-nut product; according to the invention, low-temperature drying is carried out on the product after blending or vacuum mixing, so that the prebiotic areca nuts are released along with saliva in the chewing process, and are selectively utilized by bifidobacteria and lactic acid bacteria after entering the stomach and intestine, thereby achieving the purposes of regulating intestinal flora and improving the health-care function.

The invention discloses an integrated nano platform for bimodal detection and synergistic sterilization of pathogenic bacteria as well as a preparation method and application of the integrated nano platform, and belongs to the technical field of food safety. The platform is composed of a multifunctional nano probe (MPDA / Pd SA-DA-CDs / Apt) and a magnetic separation assembly (MNRs / PGA / AM). The probe integrates enzyme-like catalysis and photo-thermal performance and is used for generating colorimetric and photo-thermal dual-mode signals so as to realize high-sensitivity and high-reliability detection of pathogenic bacteria. The magnetic separation assembly is used for specifically capturing and enriching target bacteria and eliminating matrix interference. After detection is positive, the platform can immediately start secondary propulsion synergistic sterilization: firstly, the action distance is shortened through magnetic aggregation, and then pathogenic bacteria are efficiently inactivated and biological membranes are disintegrated by utilizing the synergistic effect of near-infrared laser excitation photothermal effect and active oxygen. According to the invention, the integration of detection and disinfection is realized, the operation is convenient, and the method has important application value in the fields of food safety and biomedicine.