97results about How to "Increase enzyme activity" patented technology

The application provides an arginine deiminase mutant with alkali resistance, and the amino acid sequence of the mutant is SEQ ID NO:3. When L-arginine is used as a substrate to synthesize L-citrulline, the pH value of a reaction system can be as high as pH 11 or higher, and hydrochloric acid neutralization is not needed, so that the cost of product separation and purification and waste water treatment is significantly reduced.

The application belongs to the technical field of bioengineering, and particularly relates to a xanthan gum cleavage ancestral enzyme AncXLY196 based on ancestral sequence reconstruction, an amino acid sequence of which is shown as SEQ ID NO. 2. Based on the xanthan gum cleavage ancestral enzyme, a mutant AncXLY196-X7 is further obtained, an amino acid sequence of which is shown as SEQ ID NO. 4, xanthan gum degradation activity of which reaches 2.5 times of that of the xanthan gum cleavage ancestral enzyme, and the optimal catalytic temperature of the xanthan gum cleavage ancestral enzyme and the mutant thereof is increased to 45 DEG C, and the enzyme activity of the mutant of the xanthan gum cleavage ancestral enzyme is reserved by 50-80% after being treated at 45-55 DEG C for 12-24 h. The application provides a new enzyme resource for efficient enzymatic degradation of xanthan gum and preparation of functional oligosaccharides.

The application discloses a preparation method of a copper-based metal complex and application of the copper-based metal complex in antioxidation activity, relates to the technical field of functional materials, and has the chemical formula [Cu(H3dhbdc)2(H2O)2], wherein H3dhbdc is deprotonated 2,3-dihydroxyterephthalic acid. The copper-based metal complex has specific crystal structure and spatial structure, high synthesis purity, and good stability, and can be used in antioxidation activity. Under the same condition, the scavenging ability of H4dhbdc and the copper-based metal complex on •OH and O2 •‑ is explored, the copper-based metal complex is equivalent to H4dhbdc in terms of the scavenging effect on •OH free radicals, and is better than H4dhbdc in terms of the scavenging effect on O2 •‑ free radicals, and it is shown that the complex Cu 2+ after complexation not only retains the antioxidation activity of H4dhbdc, but also enhances the enzyme activity of H4dhbdc.

The invention discloses a beta 1, 3-galactosyl transferase Pm beta 3GalT-S207H and an application thereof, and belongs to the technical field of functional enzymes. And the amino acid sequence of the beta 1, 3-galactosyl transferase Pm beta 3GalT-S207H is as shown in SEQ ID NO. 3. The invention further discloses the application of the beta 1, 3-galactosyl transferase Pm beta 3GalT-S207H in the preparation of lactose-N-tetrasaccharide. According to the invention, 1, 3-galactosyl transferase Pm beta 3GalT is subjected to mutation modification to obtain a mutant enzyme, and compared with a wild enzyme, the enzyme activity of the mutant enzyme is improved by 157.21% and is obviously improved, and the thermal stability and alkali resistance are also obviously improved. The beta 1, 3-galactosyl transferase Pm beta 3GalT-S207H disclosed by the invention has important theoretical value and application value on the industrial production of LNT (Lipoxystrobin).

The invention relates to the technical field of biosynthesis, in particular to a preparation method of gamma-aminobutyric acid. The invention provides a method for preparing gamma-aminobutyric acid, according to the method, gamma-aminobutyric acid is catalytically synthesized by using a mutant of glutamate decarboxylase screened by the inventor, the problems of low catalytic efficiency, long conversion time and limited reuse times of enzyme are solved, the immobilized enzyme can be continuously subjected to at least 20 rounds of enzyme catalytic reaction, and the yield of gamma-aminobutyric acid is increased. And moreover, the catalytic efficiency is not obviously reduced, the substrate conversion rate can still be stabilized at 99% or above, and the method is suitable for industrial production.

This invention belongs to the fields of fermentation engineering and enzyme engineering technology, specifically relating to a chitosanase fermentation method based on a Pichia pastoris expression vector and its application. The chitosanase fermentation method provided by this invention includes two stages: fermentation during the cell growth phase and fermentation during the induction phase, with strict control over the carbon source and specific feeding method at each stage. During fermentation, this invention significantly improves the expression level and absolute enzyme activity of chitosanase Baa by adding casein hydrolysate as a molecular chaperone, mannitol as an adjuvant, and further optimizing the carbon source feeding strategy and parameters such as pH and temperature. Compared with the starting process, this invention increases the chitosanase activity by 1.81 times and the protein expression level by 2.01 times. Moreover, the fermentation method of this invention has been successfully verified in a 50L pilot-scale operation, demonstrating a good foundation for industrial application and cost advantages.

The invention relates to the technical field of microorganisms, in particular to the technical field of agricultural microorganisms, and more particularly relates to a cellulose degradation composite flora as well as a construction method and application thereof. The cellulose degradation composite flora comprises a cellulose degradation bacterium, namely humid cellulomonas CW35 and an auxiliary strain used for digesting an intermediate metabolite of the humid cellulomonas CW35, and the auxiliary strain is one or more of pseudomonas Taiwan CW19, bacillus amyloliquefaciens L3 or microbacterium algal M266-2. Therefore, the feedback inhibition effect of a product in the cellulose degradation process of the cellulomonas can be destroyed, the expression and enzyme activity of cellulose degradation related genes are remarkably improved, and the decomposition utilization of cellulose-degrading bacteria, namely the wet cellulomonas CW35, on cellulose-containing wastes is effectively improved.

The invention provides an MOF-on-MOF composite material, an aptamer probe as well as a preparation method and application of the aptamer probe. The MOF-on-MOF composite material comprises an HKUST-1 material, the surface of the HKUST-1 material is coated with a Cu-BDC nanosheet; the synthesized HKUST-1 (at) Cu-BDC / Apt aptamer probe can specifically recognize AFB1, the aptamer probe can directly capture the AFB1 and adsorb the AFB1 to active sites on the surface of a material to reduce the nano-enzyme activity of the AFB1, so that quantitative colorimetric detection of the AFB1 is realized, and the aptamer probe has low detection limit, wide detection range, good selectivity and anti-interference performance on the AFB1 and can be used for detecting the AFB1. The AFB1 in a food sample can be rapidly, sensitively and selectively detected. In addition, the composite material has an adsorption effect and high catalytic activity on fungaltoxin, and AFB1 can be efficiently removed through the adsorption effect and the catalytic action.

The application discloses a key type specificity changed alpha-glucosyltransferase mutant, and belongs to the technical field of enzyme engineering and starch modification. The method is characterized in that, by analyzing the combination of Lf2970GtfB 4,3-alpha-glucosyltransferase in the active center donor / acceptor sub-site and the substrate, part of key amino acids of Lf2970GtfB are mutated into different types of amino acids, the mutant is prepared by changing the enzyme and substrate interaction force, space steric hindrance and other factors affecting the orientation of the substrate in the active center, the transglycosylation is changed, and the bond type composition of the product is changed. The application changes the bond type specificity of Lf2970GtfB 4,3-alpha-glucosyltransferase by mutation, the obtained mutant has novel 4,3 / 6-alpha-glucosyltransferase activity, and is helpful to synthesizing unique structure and more valuable alpha-glucan by using starch substrates.

The application discloses a planting method for improving tobacco quality, and the fertilization mode of the planting method is set as T3, or T4, or T5. The fertilization treatment is beneficial to tobacco plant growth, tobacco carbon and nitrogen metabolism, tobacco leaf quality, and improves tobacco leaf yield.

The invention discloses judgment and optimization of key amino acid sites for controlling sesquiterpene synthesis, and determines amino acid residues lysine or arginine or glutamine related to sesquiterpene synthesis for point mutation and combined mutation of various plant sesquiterpene synthase. Lysine or arginine or glutamine is located in a cavity among 5-10 amino acids in front of the first long alpha helix at the N end, alpha helixes (also the longest alpha helix in the protein) communicating the N end and the C end of the protein and the last 1-7 amino acids at the C end at the site. The method for determining the key amino acid can be used for efficiently screening the sesquiterpene synthase with activity, and the optimization of the amino acid of the key residue can be used for guiding the transformation of the high-yield sesquiterpene synthase for industrial production. The invention has important application value and economic benefit in the fields of biological synthase identification of sesquiterpenoids, biosynthesis of drugs, fermentation production of spices, synthesis of industrial raw materials and the like.

This invention discloses a strain of *Bacillus spp.* from soil, which was deposited at the Guangdong Provincial Center for Microbial Culture Collection on September 15, 2025, with accession number GDMCC NO.66967. This strain exhibits good heat resistance, and the mannanase it produces maintains stable enzyme activity under high-temperature conditions. Compared to hydrolases under ordinary conditions, it has greater plasticity and is suitable for the production of products or by-products in multiple fields. In addition, this strain can also be applied to the degumming process of hemp fibers, demonstrating excellent degumming effects on hemp fibers.

This invention provides an imine reductase mutant, its preparation method, and its application in the catalytic preparation of dextromethorphan intermediates. The imine reductase mutant is an imine reductase with an amino acid mutation, comprising the amino acid sequence shown in SEQ ID NO:1. The amino acid mutation type includes any one or a combination of at least two of I122T, D212A, or G228R. By introducing a mutation into the imine reductase, this invention significantly improves the enzyme's activity and stereoselectivity, enabling the high-yield synthesis of the dextromethorphan intermediate (S)-1-(4-methoxybenzyl)-1,2,3,4,5,6,7,8-octahydroisoquinoline under mild conditions, greatly reducing production costs and making it suitable for industrial production.

This invention discloses a high-activity, heat-resistant α-glucan phosphorylase mutant and its applications, belonging to the fields of genetic engineering and modern enzyme technology engineering. This invention utilizes site-directed mutagenesis technology to modify the wild-type... α‑ Dextran phosphorylase was modified to construct a series of mutants. Compared with the wild-type enzyme, the enzyme activity was increased by 1.68 to 2.49 times, and the mutants had a wider range of adaptability to temperature and pH. Among them, the mutant R282Y / H506A showed excellent thermostability. After incubation at 60℃ for 132 h, its enzyme activity was still 50.96%, and after incubation at 70℃ for 60 h, its enzyme activity was still 53.71%. The significantly improved thermostability creates better conditions for the use of this enzyme in practical applications.

The application provides a cold-adapted straw degrading and nitrogen-fixing composite microbial agent, a preparation method and application thereof, and belongs to the technical field of agricultural microorganisms.The cold-adapted straw degrading and nitrogen-fixing composite microbial agent comprises Acinetobacter guillouiae JIA101, Paenibacillus polymyxa JIA102, Raoultella sp.JIA201, Cellulosimicrobium cellulans JIA202 and Raoultella sp.JIA203.The composite microbial agent has high enzyme activity, straw degrading capacity and nitrogen-fixing capacity, and is suitable for a low-temperature environment.Pot experiment results show that under the condition of 10 DEG C, the microbial agent can significantly promote straw degradation, the straw degradation rate in soil reaches 44.99%, and is increased by 88.49% compared with a control group;and the treatment can effectively improve the soil nutrient and organic matter content.The application provides technical support for straw returning to field and soil fertilization under a low-temperature environment.

The application discloses a D-mangiferoline dehydrogenase MtOEPa mutant and application thereof, and belongs to the technical field of genetic engineering. The amino acid sequence of the D-mangiferoline dehydrogenase MtOEPa mutant is shown as SEQ ID NO. 4. The D-mangiferoline dehydrogenase MtOEPa mutant has stronger affinity to a substrate myo-inositol, higher catalytic efficiency and higher enzyme activity, and can significantly improve the conversion rate of a reaction and the yield of D-chiro-inositol when catalyzing the reaction of myo-inositol to generate D-chiro-inositol.

The invention discloses a D-formononeol dehydrogenase MtOEPa mutant and application thereof, and belongs to the technical field of gene engineering. The amino acid sequence of the D-formononol dehydrogenase MtOEPa mutant is as shown in SEQ ID NO. 4. The D-formononeol dehydrogenase MtOEPa mutant disclosed by the invention has stronger affinity to a substrate muscle inositol, higher catalytic efficiency and higher enzyme activity, and can significantly improve the conversion rate of the reaction and the yield of the D-chiral inositol when catalyzing the muscle inositol reaction to generate the D-chiral inositol.

The present application provides a kind of compound biocontrol agent and its preparation method and application technology, and it is composed of 1000ml of fermentation mixed liquor of multiple strains of biocontrol bacteria mixed in equal volume ratio and 0.5%-1.5% stabilizer with complementary mechanism and target.The fermentation concentrated solution of multiple strains of bacteria is prepared in fermentation medium to obtain the present application, which is used for preventing and controlling fusarium, pythium, phytophthora, rhizoctonia solani, ralstonia solanacearum, erwinia carotovora, streptomyces scabiei, xanthomonas campestris and other plant pathogenic bacteria and nematodes, which can inhabit in soil for a long time and spread through soil, and one or several of them can cause plant soil-borne diseases.The preparation process of the present application is not affected by too many chemical and physical factors, the activity of live bacteria and metabolites is high, the average control effect is 78%-85%, the application effect is good;The production process is simple, energy and auxiliary materials are saved, and the production cost is low.

The invention discloses a 2-keto-inositol isomerase mutant and application thereof, and belongs to the technical field of gene engineering. The 2-keto-inositol isomerase mutant is obtained by performing at least one of the following mutations on an amino acid sequence as shown in SEQ ID NO.1: (1) mutating the 63rd amino acid from L to A; (2) the 155th amino acid is mutated from E to R; and (3) the 210th amino acid is mutated from G to R. After the wild type 2-keto-inositol isomerase is mutated, the obtained 2-keto-inositol isomerase mutant is higher in enzyme activity, better in heat resistance and longer in half-life period, and when the D-chiral inositol is prepared by combining with inositol dehydrogenase, the reaction conversion rate and the yield of the D-chiral inositol are improved.

This invention relates to the field of polymer degradable materials technology, specifically to a biodegradable material, its preparation method, and its applications. The material is based on modified polylactic acid (PLA), supplemented by antioxidants, plasticizers, flame retardants, and inorganic fillers in specific weight proportions. Its unique feature lies in the polymerization of lactic acid and epicatechin imidazole ammonium chloride polymer under stannous octoate catalysis, using chemical bonding to introduce the bioactive groups of epicatechin into the PLA backbone, significantly improving the material's biodegradation rate, mechanical properties, and thermal stability. The bioactive substances and ionic groups in this material promote microbial degradation, achieving complete decomposition in a composting environment within a short time. Simultaneously, through molecular-level reinforcement and ionic cross-linking effects, the strength, toughness, and high-temperature processing performance of PLA are effectively improved. This material can be widely used in disposable tableware, food packaging films, and biodegradable agricultural mulch films.

The application discloses collagen tripeptide and a preparation method and application thereof, and belongs to the technical field of bioengineering. The preparation method comprises the following steps: obtaining bacillus velezensis with high collagenase yield through separation and identification, the bacillus velezensis belongs to probiotics, and high-activity collagenase is obtained through fermentation culture and purification; taking shark cartilage or blue fish skin as raw materials, and obtaining collagen tripeptide through the following steps of combined enzymolysis of alkaline protease and collagenase after pretreatment, inactivation, centrifugal separation and freeze-drying. The collagen tripeptide prepared by the application has a molecular weight of less than 500 Dalton, contains active components such as GHK tripeptide, is easy to absorb and has high safety, and can be used for preparing antioxidant products, anti-inflammatory products, memory-enhancing products or immunity-enhancing products. The application solves the problems of unsafe collagenase source and low collagen tripeptide preparation efficiency, and has a good industrial application prospect.

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

The invention provides a beta-1, 3-glucan hydrolase mutant and application thereof, and relates to the technical field of biology. The mutant provided by the invention is obtained by carrying out site-directed mutagenesis by taking beta-1, 3-glucan hydrolase GH3 as a wild type enzyme. Compared with a wild enzyme, the enzyme activity of the D446W mutant is improved by 54%, so that the application potential and commercial value of the D446W mutant in the fields of medicines, health care products, functional foods and the like are favorably improved.

This invention belongs to the field of food enzyme engineering technology, specifically relating to a strain of *Aspergillus echinococcosis* that produces highly efficient ester-degrading catechin tannin enzymes and its applications. The strain is classified as *Aspergillus echinococcosis* (…). Aspergillus aculeatus LS06, with accession number CGMCC No. 42170. The *Aspergillus echinococcosis* strain provided by this invention serves as a tannin-producing strain, using inexpensive agricultural waste bran as raw material, resulting in low production costs. Simultaneously, the produced tannins exhibit high enzyme activity and high catalytic efficiency for ester-type catechins, demonstrating promising application prospects in tea beverage processing.

A C-terminal truncated alginate lyase and its application. This invention belongs to the fields of bioengineering, genetic engineering, and enzyme engineering, and relates to a C-terminal truncated alginate lyase TY2 designed with molecular docking assistance, its encoding gene, recombinant vector, strain, and its application in the preparation of low-polymerization degree alginate oligosaccharides. Using wild-type MhAly6 as the parent, the truncation boundary was determined through structural prediction and molecular docking. A portion of the linker peptide was retained, and the C-terminal GH28 family domain was deleted to obtain the truncated form TY2. TY2 has approximately twice the specific activity of the wild-type enzyme, and even higher residual activity after incubation at 45°C for 1 hour, achieving a synergistic improvement in catalytic activity and thermal stability. + The relative enzyme activity reached 4.3 times that of the control group, which can degrade pretreated Sargassum powder. The product is mainly ΔDP2–ΔDP4 low-polymerization brown algae oligosaccharides, which are suitable for related enzymatic degradation and oligosaccharide preparation.

This invention discloses an organic fertilizer for increasing guava yield in saline-alkali land and its preparation method, relating to the field of biotechnology. The active ingredients of this organic fertilizer include *Bacillus horikoshii* ACCC 01061, *Bacillus safensis* CICC 21743, *Sporidiobolus salmonicolor* CICC 32895, *Trichoderma koningii* CICC 13006, and *Trichoderma longibrachiatum* ACCC 32095. This organic fertilizer can improve the yield per guava tree and the quality of the fruit grown in saline-alkali land, and has significant market application value.

The application discloses a glycosyltransferase mutant and application thereof, and the mutant is obtained by single mutation or multiple mutations of amino acids at positions 58, 181 or 371 of the amino acid sequence shown in SEQ ID NO. 4 or single mutation or multiple mutations of amino acids at positions 54, 152, 241 or 272 of the amino acid sequence shown in SEQ ID NO. 6. The glycosyltransferase is rationally modified by homologous modeling and sequence homology analysis, and a glycosyltransferase mutant with obviously improved enzyme activity is screened. Compared with the wild type, the relative enzyme activity of the mutants UGTM1-3 and UGTM2-4 is respectively improved by 2.88 times and 3.60 times compared with that before modification, and the mutants have great industrial application potential.

This invention discloses an L-rhamnose isomerase mutant and a method for preparing D-allose, belonging to the field of genetic engineering technology. The amino acid sequence of the L-rhamnose isomerase mutant is shown in SEQ ID NO.3. This invention significantly increases the enzyme activity of the L-rhamnose isomerase mutant by mutating amino acid position 268 of the wild-type L-rhamnose isomerase sequence from S to T, thereby improving the catalytic efficiency in the preparation of D-allose from D-allulose and ultimately increasing the yield of D-allose.

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 invention discloses agricultural emulsified asphalt and a preparation method thereof. The agricultural emulsified asphalt provided by the invention comprises the following components in parts by mass: 20-80 parts of asphalt; 20 to 100 parts of water; 1-20 parts of a composite emulsifier; 0.2 to 5 parts of a defoaming agent; 50 to 120 parts of biological powder; 1-5 parts of a compound fertilizer agent; and 5-40 parts of insect-expelling and weight-gaining microcapsules. After the emulsified asphalt is sprayed on the surface layer of soil, the water retention capacity of the soil can be remarkably improved, loss of the soil and fertilizer is effectively restrained, and the emulsified asphalt has efficient and lasting insect repelling capacity and nutrient slow release capacity.