25 results about "Chitosanase" patented technology

The invention provides a multi-enzyme combination for accurately characterizing a compost fermentation process and application, and belongs to the technical field of environmental biotechnology and solid waste resource utilization, the multi-enzyme combination comprises alpha-glucosidase, alpha-galactosidase, endo-1, 3-glucanase, endo-cellulase and endo-chitosanase. The multi-enzyme composition is determined by screening composting systems of different raw materials such as wheat straw, corn straw, chicken manure, alfalfa and sludge under different C / N ratios. The multi-enzyme combination can accurately characterize the four stages of temperature rise, high temperature, temperature reduction and decomposition of the compost, the enzyme activity can be determined through a plurality of detection methods such as a fluorescent color development method and a visible light color development method, so that the real-time monitoring and state evaluation of the compost process are realized, the technical support for compost process regulation and control and quality release is provided, and the application prospect is wide.

The invention discloses a chitosanase mutant S155A / T200A as well as a recombinant expression vector and application thereof, and belongs to the field of gene engineering and enzyme engineering. The specific enzyme activity of the constructed S155A / T200A reaches 1556.60 U / mg, which is 1.061 times that of the original type; the product spectrum is obviously expanded, chitooctasaccharide (DP8) which can not be generated by an original type can be efficiently synthesized, the product proportion is 0.88%, and the total proportion of high-polymerization-degree chitosan oligosaccharide (DP is greater than or equal to 5) reaches 13.47% and is 3.3 times that of the original enzyme. The half-life period of the mutant at 60 DEG C reaches 383.37 min, the catalytic durability is excellent, a new generation of enzyme preparation is provided for industrial production of chitosan oligosaccharide with the specific polymerization degree, and the mutant has wide application prospects in the fields of medicine carriers, functional food and the like.

The present application relates to a kind of chitosanase mutant WP-E80A, plasmid, recombinant bacteria and its application, belong to enzyme engineering technical field, the amino acid sequence of the chitosanase mutant as shown in SEQ ID NO:1, the amino acid sequence of wild-type chitosanase CsnWP as shown in SEQ ID NO:2.Compared with wild-type chitosanase CsnWP, the 80th amino acid is subjected to site-directed mutagenesis.The present application also provides plasmid and recombinant engineering bacteria comprising the chitosanase mutant WP-E80A gene, and the chitosanase mutant WP-E80A can be prepared to generate chitotriose with chitobiose as substrate.

The chitosan oligosaccharide enzymatic hydrolysis device comprises a working base and an enzymatic hydrolysis tank body, the working base is located at the bottom of the enzymatic hydrolysis tank body, one side of the upper end of the working base is fixedly connected with a lifting control frame, one side of the upper end of the lifting control frame is fixedly connected with an upper connecting cover plate, and the other side of the upper end of the lifting control frame is fixedly connected with a lower connecting cover plate. A first control motor is fixedly connected to the middle of the upper end of the upper connecting cover plate, a rotary control rod is movably connected to the lower end of the upper connecting cover plate, and a stirring and wall scraping telescopic mechanism is positioned and mounted at the lower end of the rotary control rod. According to the chitosan oligosaccharide enzymatic hydrolysis device for preparing chitosan oligosaccharide, stirring operation can be carried out in the enzymatic hydrolysis tank body through the arranged stirring wall scraping telescopic mechanism, meanwhile, accumulation of residues and impurities can be prevented, cross contamination is avoided, accumulation and hardening of the residues can be prevented through regular cleaning, corrosion and abrasion to equipment are reduced, and the service life of the equipment is prolonged. Therefore, the service life of equipment is prolonged.

The invention belongs to the technical field of seasoning processing, and particularly relates to a method for improving the antibacterial activity of shrimp shell powder in salt-reduced soy sauce production and use processes. The method mainly comprises the following steps: decalcifying and crushing shrimp shells by comprehensively utilizing an acid solution, microwaves and a superfine crushing technology, taking the shrimp shells as part of production raw materials of the salt-reduced soy sauce, and degrading chitin in the shrimp shells into low-molecular-weight chitosan by utilizing a chitinase system and a chitosanase system produced by microorganisms in a koji-making and soy sauce mash fermentation process. The antibacterial activity of the compound in the fermentation and use processes of the salt-reduced soy sauce is improved, and the biological safety of the salt-reduced soy sauce in the production and use processes is guaranteed. Compared with the conventional soy sauce (the saline concentration is 22%, w / v), the content of NaCl in the salt-reduced soy sauce produced by the method disclosed by the invention is reduced by more than 28%, the content of organic substances (amino acid nitrogen, total nitrogen, salt-free solids and the like) is increased, and the flavor of the salt-reduced soy sauce is improved. Therefore, the method disclosed by the invention has a wide application prospect.

The application provides a method for continuously producing chitooligosaccharide with specific polymerization degree by using an immobilized enzyme membrane reactor. The method is as follows: 1. preparing a PLGA nanofiber-temperature-sensitive hydrogel composite carrier, fixing the carrier in the inner wall of a ceramic membrane to obtain a composite carrier membrane; 2. assembling the composite carrier membrane into a folding enzyme membrane reactor with temperature control, pressure monitoring and material switching units; 3. introducing enzyme solution to fix chitosanase, and then introducing pretreated chitosan substrate to catalyze the reaction; 4. monitoring the polymerization degree on line to control the reaction process, washing the reactor after the reaction to realize continuous production, and concentrating and spray drying the product to obtain the target product. The application fuses the characteristics of multiple carriers to construct a “rigid support-flexible regulation” structure: the ceramic provides stable mechanical support, the temperature-sensitive hydrogel adjusts the swelling degree with temperature, the enzyme active site is exposed at low temperature to improve the efficiency, and the product is released by shrinking at a later stage, so that the problem of product retention and side reaction is solved.

The application provides a chitosanase and application thereof, and relates to the technical field of enzyme engineering. The amino acid sequence of the chitosanase is shown as SEQ ID NO. 1. The chitosanase prepared by the application can efficiently and controllably catalyze chitosan hydrolysis to generate chitooligosaccharide with a specific polymerization degree. The enzyme is obtained by screening from an extreme environment through metagenomic technology, has a novel sequence, unreported catalytic characteristics and can precisely regulate product composition, and meets the preparation requirements of specific high-purity chitooligosaccharide. These characteristics make the enzyme have important application value in the large-scale production of chitooligosaccharide, provide an effective way for solving the problems of single product and low purity in the traditional method, and lay a technical foundation for the development in the fields of medicine, food and agriculture.

The invention discloses screening and application of a high-yield chitosanase strain, and belongs to the field of microbial engineering and enzyme preparations. According to the invention, a strain of bacillus cereus F3 is obtained, the enzyme activity of the strain reaches 23.40 U / mL by optimizing a fermentation process, and the fermentation enzyme production time is only 36 hours; besides, it is found that the bacillus cereus F3 is a non-inducible cell-producing chitosanase strain, colloidal chitosan and powdery chitosan do not need to be added as inducers in the culture process, and the enzyme extraction process can be simplified in industrial production. The compound preparation of bacillus cereus F3 and chitosan oligosaccharide can promote corn growth under salt stress and drought stress, has more obvious growth promoting effect on plant height and stem diameter, and can improve the chlorophyll content and antioxidant enzyme activity of corn and enhance the stress resistance of crops.

This invention relates to a chitosanase mutant BAC / MH and the application of its prepared chitosan oligosaccharide in abalone preservation, belonging to the field of genetic engineering. The amino acid sequence of the chitosanase mutant BAC / MH is shown in SEQ ID NO:1. Compared with the wild-type chitosanase Csn-BAC, cysteine ​​at position 77 is mutated to methionine and threonine at position 236 is mutated to histidine. The chitosanase mutant BAC / MH of this invention can catalyze the production of chitosan oligosaccharide from chitosan, with a catalytic activity 6.13 times that of the wild-type chitosanase Csn-BAC. Furthermore, the chitosan oligosaccharide can improve the quality of abalone during cold storage preservation.

The present application relates to a kind of chitosanase mutant CsnW27-HF, plasmid, recombination bacteria and its application, belong to enzyme engineering technical field, the amino acid sequence of the chitosanase mutant as shown in SEQ ID NO:1, the amino acid sequence of wild-type chitosanase CsnW27 as shown in SEQ ID NO:2.Compared with wild-type chitosanase CsnW27, the 82th and 99th amino acid are subjected to site-directed mutagenesis.The present application also provides plasmid and recombination engineering bacteria comprising the chitosanase mutant CsnW27-HF gene, the enzyme activity of the mutant is increased by 2.36 times compared with wild type.

The invention discloses chitosan microparticle-vegetable protein emulsion microcapsule powder as well as a preparation method and application thereof. The preparation method comprises the following steps: dissolving food-grade chitosan in an acetic acid solution, adjusting the pH value to 5.5, adding a chitosanase solution, performing enzymolysis, centrifuging, collecting supernate, and performing freeze drying to obtain chitosan microparticles; the preparation method comprises the following steps: dissolving chitosan microparticles in deionized water, adding a vegetable protein solution and edible salt, carrying out homogenization treatment at 8000 rpm for 1 min, continuously stirring at 50 DEG C for 2-4 h, dropwise adding vegetable oil, continuously homogenizing at 8000-16000 rpm for 3 min to form a primary emulsion, and carrying out ultrasonic / supercritical treatment on the primary emulsion to form a stable emulsion; performing low-temperature vacuum spray drying on the emulsion to obtain chitosan microparticle-vegetable protein emulsion microcapsule powder; the cereal product realizes effective reduction of postprandial glycemic index, and is suitable for developing a new generation of healthy bread products.

The invention provides a preparation method of a high-temperature-resistant antibacterial sputum suction catheter, and belongs to the technical field of medical instruments. The preparation method comprises the following steps: quaternary ammonium salt chitosan is treated by chitosanase to obtain modified chitosan, polytetrahydrofuran, polyethylene glycol and diisocyanate react to obtain a prepolymer, the prepolymer, dimethylolpropionic acid and the modified chitosan react to obtain a polyurethane prepolymer, modified silane and the polyurethane prepolymer are mixed to obtain a mixed material, and the mixed material is dried to obtain a finished product. And performing extrusion molding on the mixture to obtain the high-temperature-resistant antibacterial sputum suction catheter. Hydrophilic groups in the modified silane and polyurethane polymer can reduce the friction force on the surface of the sputum suction catheter and reduce vascular endothelial injury; in addition, quaternary ammonium salt structures in the resveratrol and the modified chitosan can jointly destroy metabolism of bacteria to achieve a good antibacterial effect, and the combined non-antibiotic antibacterial strategy can delay generation of drug-resistant bacteria.

This invention discloses an artificial intelligence-based method for targeted optimization of chitosanase, comprising: constructing a sequence-function-product standardized association dataset containing chitosanase amino acid sequence, substrate molecular structure, enzyme activity data, and product polymerization degree data; encoding the enzyme sequence using a protein language model and the substrate structure using a chemical language model to obtain enzyme sequence feature vectors and substrate structure feature vectors, and forming a multimodal fusion feature vector by concatenating the vectors; inputting the fusion features into an Extra Trees ensemble model for training to predict the probability of enzyme-substrate interaction, enzyme activity, and product polymerization degree; and performing targeted screening of target chitosanase and determining mutation sites based on the prediction results to obtain optimized mutants. This invention can significantly improve the efficiency and prediction accuracy of chitosanase modification, reduce experimental screening costs, and achieve efficient and accurate optimization of chitosanase.

The application provides a multi-enzyme combination and application for accurately characterizing compost fermentation process, and belongs to the technical field of environmental biotechnology and solid waste resource utilization, and the multi-enzyme combination comprises alpha-glucosidase, alpha-galactosidase, endo-1, 3 glucanase, endo-cellulase and endo-chitosanase. The multi-enzyme combination is determined by screening the compost systems of different raw materials such as wheat straw, corn straw, chicken manure, alfalfa, sludge and the like under different C / N ratios. The multi-enzyme combination can accurately characterize four stages of composting, i.e. temperature rising, high temperature, temperature falling and maturity, and the enzyme activity can be determined by various detection methods such as fluorescence colorimetry and visible light colorimetry, so that the real-time monitoring and state evaluation of the composting process can be realized, technical support for the process regulation and quality release of composting is provided, and the application prospect is wide.

The invention discloses a mutant gene with improved thermal stability and specific enzyme activity of chitosanase as well as a recombinant expression vector and a recombinant strain of the mutant gene, and belongs to the technical field of gene engineering. The mutant Mut4 constructed by the invention has good thermal stability at 60 DEG C and 70 DEG C, 68.74% and 25.45% of enzyme activity are respectively retained after incubation for 2 hours, and meanwhile, the specific activity of the mutant Mut4 is obviously improved compared with that of a wild type. According to the method, good heat resistance of the chitosanase at high temperature is achieved, and good industrial application prospects are shown.

The invention discloses a method and a device for continuously preparing narrow-distribution chitosan oligosaccharide. The method comprises the following steps: S100, adsorbing chitosanase on a magnetic carrier, so as to prepare magnetic immobilized chitosanase; s200, the prepared magnetic immobilized chitosanase is placed in a reaction container, a chitosan substrate solution is continuously introduced into the reaction container for an enzymolysis reaction, and a reaction product is separated through an ultrafiltration membrane; s300, collecting the separated penetrating fluid, re-introducing the trapped fluid trapped by the ultrafiltration membrane into the reaction container, and repeating the step S200; wherein the reaction conditions of the enzymolysis reaction in the step S200 are as follows: the pH value is 6.0-6.5, and the temperature is 40-45 DEG C; the molecular weight cutoff of the ultrafiltration membrane is 5-10 kDa. Through effective coupling of the magnetic immobilized chitosanase and the ultrafiltration membrane separation process with the specific molecular weight cut-off, efficient, continuous and stable production of the narrow-distribution chitosan oligosaccharide is successfully realized.

The application provides a chitosanase and application thereof, and relates to the technical field of enzyme engineering. The amino acid sequence of the chitosanase is shown as SEQ ID NO. 1. The novel chitosanase prepared by the application can efficiently and controllably catalyze chitosan hydrolysis to generate chitooligosaccharide with a specific polymerization degree. The enzyme is obtained by screening from an extreme environment through metagenomic technology, has a novel sequence, unreported catalytic characteristics and can precisely regulate product composition, and meets the preparation requirements of specific high-purity chitooligosaccharide. These characteristics make the enzyme have important application value in the large-scale production of chitooligosaccharide, provide an effective way for solving the problems of single product and low purity in the traditional method, and lay a technical foundation for the development in the fields of medicine, food and agriculture.

The present application relates to chitosanase mutants producing chitotetraose and application thereof, and belongs to the field of enzyme engineering. Specifically, the chitosanase is derived from GH46 family glycoside hydrolase (BsCsn46A) of Bacillus subtilis, the chitosanase mutant is that the aspartic acid at the 151th position of the amino acid sequence of BsCsn46A is mutated into serine, the mutant is D151S; or mutated into threonine, the mutant is D151T; or mutated into tyrosine, the mutant is D151Y. The mutant has the ability of hydrolyzing chitosan to produce chitotetraose.

The invention relates to a chitosanase mutant CsnW27-HF, a plasmid, a recombinant bacterium and application of the chitosanase mutant CsnW27-HF, and belongs to the technical field of enzyme engineering, the amino acid sequence of the chitosanase mutant is shown as SEQ ID NO: 1, and the amino acid sequence of wild chitosanase CsnW27 is shown as SEQ ID NO: 2. Compared with wild chitosanase CsnW27, the chitosanase CsnW27 has the advantage that site-specific mutagenesis is carried out on 82nd and 99th amino acids. The invention further provides plasmids and recombinant engineering bacteria containing the chitosanase mutant CsnW27-HF gene, and the enzyme activity of the mutant is improved by 2.36 times compared with that of a wild type.

The application belongs to the technical field of chitosan oligosaccharide preparation, and specifically discloses a low-polymerization-degree chitosan oligosaccharide as well as a preparation method and application thereof. First, chitosan and an organic acid solution are prepared into a chitosan colloidal solution; then, pectinase is used for pretreatment, and chitosanase is added for enzymolysis treatment to obtain an enzymolysis solution; after the enzymolysis solution is inactivated, centrifugal treatment and fractional alcohol precipitation are performed to obtain the low-polymerization-degree chitosan oligosaccharide with a polymerization degree of 2-4. The application adopts a double-enzyme hydrolysis strategy of pectinase and chitosanase, the pretreatment of pectinase can effectively improve the accessibility of the substrate, and a synergistic effect is generated with chitosanase, so that the degradation efficiency is significantly improved; the method has the advantages of mild process conditions and green environmental protection, and the prepared low-polymerization-degree chitosan oligosaccharide has significant anti-inflammatory activity.

The invention discloses a chitosanase mutant capable of producing chitobiose and application of the chitosanase mutant. The chitosanase mutant is derived from glucoside hydrolase chitosanase of a bacillus subtilis GH46 family, and compared with wild type chitosanase producing chitodisaccharide and chitotriose, the chitosanase mutant has the advantage that the hydrolysate is mainly chitodisaccharide. According to the invention, two chitosanase mutants are obtained, and the mutants are obtained by site-specific mutagenesis of tyrosine at the 236th site into arginine and glycine on the basis of wild chitosanase. The mutant can hydrolyze chitosan under mild conditions to produce chitosan oligosaccharide with single polymerization degree, and provides great help for separation and purification work in chitosan oligosaccharide production.

The application provides a high-temperature-resistant and antibacterial sputum suction catheter and a preparation method thereof, and belongs to the technical field of medical devices. The preparation method comprises the following steps: modifying chitosan by treating quaternary ammonium salt chitosan with chitosanase to obtain modified chitosan, reacting polytetrahydrofuran, polyethylene glycol and diisocyanate to obtain a prepolymer, reacting the prepolymer, dimethylol propionic acid and the modified chitosan to obtain a polyurethane prepolymer, mixing modified silane and the polyurethane prepolymer to obtain a mixture, and extruding the mixture to obtain the high-temperature-resistant and antibacterial sputum suction catheter. In the application, the hydrophilic groups in the modified silane and the polyurethane polymer can reduce the friction of the surface of the sputum suction catheter and reduce the injury to the vascular endothelium. In addition, the quaternary ammonium salt structure in resveratrol and the modified chitosan can jointly destroy the metabolism of bacteria to achieve good bacteriostatic effect, and the combined non-antibiotic antibacterial strategy can delay the generation of drug-resistant bacteria.

The application discloses a chitosanase, a preparation method and application thereof, and belongs to the technical field of chitosanase preparation. The chitosanase has high chitosan hydrolysis activity, and the crude enzyme solution produced by fermentation has a hydrolysis capacity of degrading 2 g of low deacetylation degree chitosan with 1 mL of the crude enzyme solution (protein content is about 0.39 mg), has application potential of replacing existing commercial enzymes for large-scale preparation of chitooligosaccharides, and has a good industrial application prospect.

The application belongs to the technical field of biotechnology, and particularly relates to a high-efficiency expression of a Kluyveromyces marxianus strain and application thereof. The Kluyveromyces marxianus strain is obtained by using CRISPR / Cas9 gene editing technology to knock out genes in a protein synthesis metabolic pathway, a secretion and transport pathway, a cytoskeleton synthesis or an intercellular information transmission pathway in a genome of the Kluyveromyces marxianus, and taking the Kluyveromyces marxianus FIM-1 in which a key gene URA3 of a uracil synthesis pathway is knocked out as a starting strain. A FIM-1 ura3Delta mnn11Delta is screened and obtained, and the alpha-galactosidase secretion expression level can be increased by more than 3 times. The Kluyveromyces marxianus strain can be applied to high-efficiency preparation of biological enzymes such as alpha-galactosidase, ferulic acid esterase, chitosanase, saccharifying enzyme, xylanase, mannanase, cellulase and beta-amylase, and has high industrial application value.