71 results about "Chitosanase" patented technology

The invention discloses a chitosanase mutant which is derived from bacillus subtilis and has the capacity of hydrolyzing chitosan to produce chitosan disaccharide per unit and belongs to a GH46 family, and application of the chitosanase mutant in hydrolyzing chitosan to produce chitosan oligosaccharide. Compared with wild type chitosanase capable of producing chitodisaccharide and chitotriose, the chitosanase mutant has the advantage that the chitodisaccharide can be produced per unit when the chitodisaccharide is hydrolyzed by the chitosanase mutant. The invention provides eight kinds of chitosanase mutants, and the mutants are obtained by carrying out site-specific mutagenesis on 21st-site glycine on the basis of wild type chitosanase and respectively mutating the 21st-site glycine into lysine, arginine, leucine, histidine, methionine, tyrosine, proline and glutamine. The mutant can hydrolyze chitosan under mild conditions to produce chitosan oligosaccharide with single polymerization degree, and can greatly relieve the difficulty in separation and purification in chitosan oligosaccharide production.

The invention relates to the technical field of low-temperature microbial agents. The invention provides a bacterium-enzyme compound preparation for straw degradation and application and a use method thereof. The bacterium-enzyme compound preparation comprises a bacterium agent and an enzyme agent, the microbial agent comprises lactobacillus plantarum, bacillus subtilis, trichoderma viride and pichia guilliermondii; the enzyme agent comprises amylase, chitosanase, pectinase, cellulose, hemicellulase and lignin peroxidase. The use effect of the composite preparation is superior to the treatment effect of a single strain or an enzyme preparation, and straw can be efficiently degraded and converted in the low-temperature environment of 10-15 DEG C. The environmental limitation of cold regions is broken through, and the efficient degradation and conversion of the straws are realized. Meanwhile, the bacterium-enzyme synergism can effectively shorten the fermentation period, accelerate the composting effect of the fertilizer and improve the soil fertility and the microbial activity.

The invention belongs to the technical field of chitosan oligosaccharide preparation, and particularly relates to a method for preparing chitosan oligosaccharide based on compound enzyme. According to the method for preparing the chitosan oligosaccharide based on the compound enzyme, a multi-enzyme synergistic system is matched with the design of a specific protective agent, chitosanase and chitinase can cooperatively cut beta-1, 4 glycosidic bonds of chitosan and control molecular weight distribution of products, meanwhile, chitinase can directionally cut the beta-1, 4 bonds at the tail end of chitosan, and the molecular weight distribution of the products is controlled. The papain is used for removing protein impurities in the chitosan to realize accurate control of the polymerization degree. Besides, a specific protective agent matched with the multi-enzyme synergistic system is specifically designed, the specific protective agent and the multi-enzyme composition act together, the molecular weight distribution width can be remarkably reduced, the yield and the DP 4-8 proportion can be increased, meanwhile, physical field ultrasonic assistance is added in the enzymolysis treatment process, and the enzymolysis treatment efficiency is improved. The combination of the substrate and the enzyme is further promoted, and the reaction time is shortened.

The invention relates to the technical field of stomach filling agents, and particularly discloses a stomach filling agent and a preparation method thereof. The stomach filling agent is prepared from, by weight, 50-75 parts of composite hydrogel, 1.7-2.8 parts of digestion promoting microcapsules and 0.7-1.2 parts of helicobacter pylori resisting matter, the composite hydrogel is formed by crosslinking sodium alginate and sulfhydrylated fructose-chitosan, the capsule wall of each digestion promoting microcapsule is gelatin and sodium alginate, and the capsule wall of each digestion promoting microcapsule is gelatin and sodium alginate. The core of the digestion promoting microcapsule is chitosanase; in addition, the preparation method disclosed by the invention has the advantages of reducing the stimulation of the gastric filling agent to gastric mucosa and improving the multifunctionality of the gastric filling agent.

The invention relates to the technical field of active substance preparation, in particular to a high-concentration chitosan solution as well as a preparation method and application thereof. The preparation method of the high-concentration chitosan comprises the following steps: (1) mixing chitosan with water to obtain a high-concentration chitosan mixture; (2) adding acid and chitosanase ShCsn46 into the high-concentration chitosan mixture, and mixing for 20 to 60 minutes, so as to obtain a high-concentration chitosan solution; the mass volume ratio of the chitosan to the water in the step (1) is (11-13) g: (87-89) mL. Through TLC and HPLC, the enzymolysis product is composed of (GlcN) 2-(GlcN) 6 oligosaccharide, the content of (GlcN) 3 is the highest, and the content of (GlcN) 6 is the lowest. Therefore, the method disclosed by the invention can be used for preparing the chitosan solution of which the concentration is up to 12wt%, and provides a basis for preparing the high-concentration chitosan solution in the fields of medicines and health care product development.

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 invention discloses a chitosanase mutant as well as a construction method and application thereof, the mutation position of the chitosanase mutant CsnBV2 is site-specific mutagenesis of Lys199Glu and Lys202Asp on an amino acid sequence of aspergillus fumigatus chitosanase, and the amino acid sequence of the chitosanase mutant CsnBV2 is as shown in SEQ ID NO. 1. The catalytic activity of the chitosanase mutant and the total degree of polymerization (DP) of hydrolysate are synchronously improved, the activity is improved by about 1.4 times compared with that of starting enzyme, the proportion of oligosaccharide with the degree of polymerization (DP) of 5 or above in enzymatic hydrolysate is 2.28 times that of the starting enzyme, and constructed pichia pastoris engineering bacteria capable of efficiently secreting and expressing CsnBV2 have good industrial application value.

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

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 present invention belongs to the field of enzyme engineering technology and discloses chitosanase mutants capable of producing chitotetraose and their applications. Chitosanase (BsCsn46A), a GH46 family glycoside hydrolase derived from Bacillus subtilis, whose amino acid sequence is shown in SEQ ID NO: 1, was subjected to saturation mutagenesis at amino acid residue 203 to screen for mutants with chitotetraose production potential. The resulting chitosanase mutants are E203M, E203S, E203R, E203H, E203N, E203C, E203Q, E203G, E203T, E203V, and E203P. Hydrolysis analysis confirmed that the resulting mutants possess the ability to produce chitotetraose.

Described herein are biological devices and methods for using the same to produce a polyactive carbohydrate. The biological devices include microbial cells transformed with a DNA construct containing genes for producing a chitin synthase, a chitosanase, and a chitin deacetylase. In some instances, the biological devices also include a gene for lipase. Methods for using the polyactive carbohydrate are also provided herein, including, but not limited to, enhancing the physiological properties of plants; medical applications; applications in the construction, materials science, and home goods industries; personal care, grooming, cosmetics, and oral care compositions containing the polyactive carbohydrate; methods for water decontamination; and the production of polyurethanes.

The invention discloses a preparation method and an application of chitosanase NFCSN. According to the present invention, a potential chitosanase gene derived from Neosatora fischeri is subjected to secretory expression in pichia pastoris, such that the potential chitosanase gene derived from Neosatora fischeri can be obtained, the chitosanase obtained by the invention has higher hydrolytic activity to a chitosan substrate, a crude enzyme liquid generated by shake flask fermentation has the capability of degrading 5g of chitosan by 1mL (the content of crude protein is about 0.23 mg), while about 150mg of non-specific commercial neutral protease is needed for hydrolyzing the same amount of chitosan, the enzymolysis efficiency is improved by more than 600 times, and the enzymolysis time is shortened by more than 30 minutes. The industrial application potential of large-scale preparation of chitosan oligosaccharide is realized.

The present invention belongs to the technical field of enzyme engineering, and specifically relates to a chitosanase mutant with improved catalytic activity by changing the acidity and alkalinity of the substrate channel. Based on the substrate channel-regulated Bacillus subtilis chitosanase BsCsn46A, the 49th alanine of the chitosanase with the amino acid sequence shown in SEQ ID NO: 1 is mutated to the basic amino acid lysine, and the mutant is A49K. Compared with the wild-type chitosanase, the chitosanase mutant of the present invention uses chitosan as a substrate, and its catalytic activity is 1.13 times higher than that of the wild-type.

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 present invention discloses a chitosanase mutant with enhanced catalytic activity and its application, belonging to the field of enzyme engineering technology. The chitosanase is derived from the family 46 glycoside hydrolase (BsCsn46A) of Bacillus subtilis. The chitosanase mutant, E203A, has a glutamic acid at position 203 of the BsCsn46A amino acid sequence mutated to alanine, an amino acid with a small side chain. Using chitosan as a substrate, the mutant exhibits significantly enhanced catalytic activity compared to the wild type.

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.

The invention discloses streptomyces mobaraensis for overexpressing chitosanase, and belongs to the technical field of genetic engineering. According to the invention, smCsn46 is integrated near a high expression site tg of streptomyces mobaraensis through a CRISPR (clustered regularly interspaced short palindromic repeats) technology, a recombinant strain smY2022-delta tg-smCsn46 is constructed and obtained, and the enzyme activity of the strain can reach 5.52 U / mL after the strain is fermented for 48 hours. The invention also verifies the enzymatic properties of smCsn46, and provides the application of the smCsn46 in the aspect of hydrolysis preparation of chitosan oligosaccharide of DP 2-6, thereby laying a theoretical foundation for the application of the smCsn46 in different fields.

The invention relates to the field of agriculture, discloses a Citrus Huanglongbing prevention and control method and system based on a composite lysozyme preparation, and provides a composite lysozyme synergistic prevention and control technology for solving the problems that pesticide residues exceed the standard, pathogenic bacteria are resistant to drugs, ecological balance is damaged and the like due to existing chemical pesticides. The preparation comprises the following components in percentage by weight: 30-50% of egg white lysozyme, 25-35% of chitosanase, 20-30% of a plant-source synergist (a mixture of citrus essential oil and tea polyphenol) and 3-8% of trehalose. The pathogen-medium synchronous targeting is realized through a triple action mechanism: (1) lysozyme is used for cracking a phloem bacitracin peptidoglycan cell wall; (2) degrading the chitin layer of the middle intestine of the phylloxera (the fatality rate is greater than or equal to 91.5%) by using the chitosanase; 3, the citrus essential oil interferes with smell localization of the phylloxera, intelligent prevention and control are achieved through a three-level prevention and control system, efficiency and labor are saved, and the scheme is remarkably superior to a traditional

The invention discloses a chitosanase BsCsn46A mutant and application of the chitosanase BsCsn46A mutant in preparation of chitotetraose, and belongs to the field of enzyme engineering. The chitosanase mutant with the chitotetraose production potential is obtained by mutating key sites of a chitosanase substrate channel. The GH46 family glucoside hydrolase chitosanase (BsCsn46A) is derived from bacillus subtilis, and the amino acid sequence of the GH46 family glucoside hydrolase chitosanase is as shown in SEQ ID NO: 1. Specifically, the 50 amino acid residue of BsCsn46A is subjected to saturation mutation, mutants with the chitotetraose producing potential are screened out, and the mutants are T50V, T50G, T50Y, T50L, T50F, T50S, T50I, T50R, T50C, T50D, T50P, T50Q, T50H and T50N, and the mutants are T50V, T50G, T50Y, T50L, T50F, T50S, T50I, T50R, T50C, T50D, T50P, T50Q, T50H and T50N. Through hydrolysis result analysis, compared with a wild type hydrolysate, the chitosanase mutant has the potential of producing chitotetraose.

The present invention relates to a chitosanase mutant, plasmid, recombinant bacteria and application thereof for changing the polymerization degree of a product, belonging to the field of enzyme engineering technology, wherein the mutant is Csn-BJ-A134C or Csn-BJ-Q97K, the amino acid sequence of the mutant Csn-BJ-A134C is SEQ ID NO:1, the amino acid sequence of the mutant Csn-BJ-Q97K is SEQ ID NO:2, and the amino acid sequence of the wild-type chitosanase Csn-BJ is shown in SEQ ID NO:3. The present invention also provides a recombinant vector, recombinant bacteria and enzyme preparation containing the mutant gene and application thereof. The mutant of the present invention is derived from the chitosanase Csn-BJ of the GH46 family, and the catalytic activity of the chitosanase is improved by molecular mutation modification of the chitosanase, and the polymerization degree of the final product chitosan oligosaccharide is changed, so that the polymerization degree of its minimum hydrolysis substrate is increased, laying the foundation for its industrial application.

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 invention discloses a chitosanase CsnQB‑E206A‑elgii and its application in the preparation of chitosan oligosaccharide functional beverages, belonging to the technical field of chitosanase. The amino acid sequence of the chitosanase CsnQB‑E206A‑elgii is shown in SEQ ID NO.5. The application of the chitosanase CsnQB‑E206A‑elgii in the degradation of chitosan. The application of the chitosanase CsnQB‑E206A‑elgii in the preparation of chitosan oligosaccharide functional beverages. The chitosanase CsnQB‑E206A‑elgii of the present invention is obtained by mutation modification of the chitosanase CsnQB, has higher enzyme activity on colloid chitosan and powdered chitosan, can be used to hydrolyze chitosan in different forms, and has broad application prospects.

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 present invention relates to genetic engineering technology, and discloses a chitosanase, its encoding gene, recombinant vector, recombinant strain, fermenting agent and enzyme preparation, as well as their applications. The pure enzyme activity of this chitosanase is high, and it has obvious acid stability. When stored overnight under the condition that the optimal pH is 5.0, the enzyme activity only decreases by 8%. When stored overnight in the pH range of 3.0 - 6.0, the remaining enzyme activity is above 60%. It has high acid resistance and a large acid-resistant range, and has great application potential in the industrial production of chito-oligosaccharide. The recombinant strain provided by the present invention can efficiently produce chitosanase through high-density fermentation, and has prospects for industrial application.

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.