1601 results about "Catalytic efficiency" patented technology

The invention provides a carbonyl reductase mutant. The carbonyl reductase mutant is obtained by performing single-point mutation or multi-point combined mutation on the 17th site, the 40th site and the 64th site of an amino acid sequence as shown in SEQ ID NO.1. The invention also provides a coding gene, a recombinant vector containing the coding gene, a co-expression engineering bacterium and an application of the co-expression engineering bacterium. Compared with a wild type enzyme, the carbonyl reductase mutant has high activity and high stereoselectivity, the enzyme activity can reach more than two times that of the wild type enzyme, the catalytic efficiency on a substrate precursor ketone is remarkably improved, the yield of a statin drug intermediate and chiral alcohol synthesized by an enzyme method of the carbonyl reductase mutant is remarkably improved, and the yield of a rosuvastatin intermediate (3R, 3R, 3R, 3R, 3R, 3R, 3R, 3R, 3R, 3R, 3R, 3R, 3R, 3R, 3R, 3R, 3R, 3R, 3R, 3R, 3R) is remarkably improved. The highest yields of the (3R, 5R)-6-chloro-3, 5-dihydroxyhexanoic acid tert-butyl ester and the atorvastatin intermediate (3R, 5R)-6-cyano-3, 5-dihydroxyhexanoic acid tert-butyl ester reach 99% and 97.6% respectively, e.e. Is larger than 99%, and the method has high industrial application value.

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 discloses a high-efficiency lysine decarboxylase mutant and an application of the high-efficiency lysine decarboxylase mutant in synthesis of pentamethylene diamine. A series of mutants including a single mutant (such as N218G, T222V, C244P and the like), a double mutant and a three mutant are obtained by carrying out multi-site mutation on wild type lysine decarboxylase (SEQ ID NO.2) from Klebsiella grimontii. The catalytic efficiency of the mutant is remarkably improved, and the activity of the mutant is improved by 5.0-10.2 times compared with that of a wild type enzyme. According to the method disclosed by the invention, the substrate conversion rate of 99% or above can be realized within 2 hours through an optimized process of constructing an expression vector and a genetically engineered bacterium, inducing expression of lysine decarboxylase and synthesizing 1, 5-pentanediamine by utilizing a whole-cell catalysis technology. Compared with a traditional chemical method and a natural enzyme method, the method disclosed by the invention has the advantages of simplified process, high catalytic efficiency, low production cost and the like, and is suitable for producing bio-based 1, 5-pentamethylene diamine and nylon 56 salt.

The invention discloses a haloalkane dehalogenase mutant and an application thereof in degradation of 1, 2, 3-tribromopropane, haloalkane dehalogenase DhaA31 coded by dhaA gene of a Rhodococcus rhodococcus NCIMB 13064 strain is modified to obtain the haloalkane dehalogenase mutant F168W / I246C, the haloalkane dehalogenase mutant has high degradation efficiency on haloalkane pollutant 1, 2, 3-tribromopropane, and the haloalkane dehalogenase mutant has high degradation efficiency on haloalkane pollutant 1, 2, 3-tribromopropane under the condition of water phase normal temperature. The degradation rate of the alkyl halide dehalogenase mutant to 10 mM of 1, 2, 3-tribromopropane within 1 h reaches 100%, and the degradation rate of the alkyl halide dehalogenase mutant to 10 mM of 1, 2, 3-tribromopropane reaches 100%. The haloalkane dehalogenase mutant has high stereoselectivity on (R)-2, 3-dibromo-1-propanol, and the e.r. Value of the haloalkane dehalogenase mutant reaches 6: 94. The haloalkane dehalogenase mutant provided by the invention has high catalytic efficiency and high stereoselectivity, is beneficial to recognition and further degradation of downstream enzymes, and has a good application prospect in bioremediation of emerging haloalkane pollutants.

The invention belongs to the field of enzymatic preparation of structural phospholipids, and particularly relates to a method for preparing phosphatidylserine through interfacial enzyme catalysis. A series of high-activity immobilized phospholipase are prepared by innovatively adopting bifunctional group modified hollow mesoporous silica microspheres as a carrier and adsorbing immobilized phospholipase D. The catalyst has the functions of a catalyst and an emulsifier, and a Pickering emulsion interfacial enzyme catalysis system can be efficiently constructed. In the system, the phosphatidylcholine and the serine are efficiently converted into the phosphatidylserine through a phosphatidyl transfer reaction, the conversion rate of the phosphatidylserine within 20 minutes can reach 85%-95%, and the catalytic efficiency reaches up to 372 mmol / (g.h). In addition, after the catalyst is recycled for 10 times, the conversion rate is still kept at 70.9%, and the catalyst shows excellent stability and reusability. The method has the remarkable advantages of being mild in reaction condition, high in catalytic efficiency, capable of being repeatedly used and the like, and a new technical approach is provided for industrial production of phosphatidylserine.

The invention relates to the technical field of biodiesel hydrogenation catalysts, and particularly discloses a hydrogenation catalyst of organic bentonite loaded cerium-zirconium solid solution and nickel-molybdenum phosphide as well as a preparation method and application of the hydrogenation catalyst. The hydrogenation catalyst with the organic bentonite loaded with the cerium-zirconium solid solution and the nickel-molybdenum phosphide comprises an organic bentonite carrier, the cerium-zirconium solid solution and the nickel-molybdenum phosphide, the loading capacity of the cerium-zirconium solid solution on the organic bentonite carrier is 2-2.5 wt%; the cerium-zirconium solid solution comprises cerium dioxide and zirconium dioxide; the loading capacity of the nickel molybdenum phosphide on the organic bentonite carrier is 10-15 wt%; and the nickel molybdenum phosphide is Ni2Mo3P. The organobentonite carrier provides an acid site and promotes deoxidation path optimization, the layered structure of the organobentonite carrier can limit the cerium-zirconium solid solution and the nickel-molybdenum phosphide, and organic groups are also embedded into the layered structure, so that the organic compatibility of the organobentonite carrier to biodiesel is improved, and the catalytic efficiency is improved. The cerium-zirconium solid solution provides oxygen vacancies, promotes hydrogenation / deoxidation, and improves the thermal stability and sintering resistance of the catalyst.

The invention discloses a high-stability hydroxysteroid dehydrogenase mutant, a co-immobilized enzyme construction method and application. According to the invention, a site-directed mutant library is constructed based on computer-aided design, and mutants with significantly improved thermal stability and greatly improved catalytic efficiency compared with wild type mutants are obtained through screening; meanwhile, a co-immobilized enzyme construction method based on electrostatic adsorption and chemical crosslinking is established, the hydroxysteroid dehydrogenase mutant and lactic dehydrogenase are co-immobilized, the co-immobilized enzyme can still keep high activity under high substrate concentration, and the conversion rate is still maintained to be 90% or above after 30 batches of co-immobilized enzyme are repeatedly used. And an important foundation is laid for industrial application of the hydroxysteroid dehydrogenase.

The invention belongs to the field of biological catalysis, and discloses a high-activity PET hydrolase mutant and application thereof. The mutant of the thermophilic PET hydrolase provided by the invention is as shown in 1), 2) or 3): 1) a protein corresponding to an amino acid sequence SEQ ID NO.4; 2) a protein corresponding to the amino acid sequence of SEQ ID NO.6; and 3) a protein corresponding to the amino acid sequence of SEQ ID NO.8. Experiments prove that the modified mutant shows higher catalytic efficiency on PET hydrolysis and can keep activity for a long time at the optimal temperature for PET depolymerization. The activity of the mutant protein BhrM3 for catalyzing PET hydrolysis is improved by 1.82 times compared with that of a wild type and is 1.22 times that of efficient PET hydrolase LCC-ICCG, and the protein melting temperature reaches 92.9 DEG C.

The invention discloses a tryptophan enzyme mutant and application thereof. The tryptophan enzyme mutant is obtained by mutation of at least one site of the 50th amino acid L, the 394th amino acid V and the 395th amino acid E of a tryptophan enzyme parent. The tryptophan enzyme mutant disclosed by the invention has good substrate bias, particularly has better selectivity and catalytic efficiency on 6 '-halogenated tryptophan, and not only simplifies the production process, but also improves the production efficiency when being used for biosynthesis production of the tylosin.

The invention belongs to the technical field of enzyme engineering, and particularly relates to a P450 peroxygenase mutant and application of the P450 peroxygenase mutant in degradation of phenol environmental pollutants. The mutant is formed by mutating phenylalanine into alanine from the 46th amino acid of P450 peroxygenase with an amino acid sequence as shown in a sequence table SEQ ID NO.1, and the amino acid sequence of the P450 peroxygenase is as shown in a sequence table SEQ ID NO.2. The P450 peroxygenase mutant provided by the invention has the advantages of high catalytic efficiency, high protein expression quantity, low industrial cost and the like. The operation process for degrading the phenol environmental pollutants is simple, the process is mature, the cost is low, harmful impurities are not contained, and the method is non-toxic and environment-friendly.

The invention belongs to the technical field of microbial genetic engineering, and particularly relates to an alpha-2, 3-sialyltransferase mutant and application thereof. The a-2, 3-sialyltransferase mutants V175N, P198A, G173D, D174Q, F196K and A315H are obtained by performing site-specific mutagenesis on six amino acids in an a-2, 3-sialyltransferase amino acid sequence coded by a gene derived from Campylobacter jejuni (OH4384), the yield of 3 '-sialyllactose is remarkably increased by single-point mutagenesis of the V175N, the yield of 3'-sialyllactose is remarkably increased by single-point mutagenesis of the V175N, the yield of 3 '-sialyllactose is remarkably increased by single-point mutagenesis of the P198A, the G173D, the D174Q, the F196K and the A315H, the optimal recombinant microbial strain 3 '-SL-09 (V175N / P198A / D174Q) is obtained through combination of multiple mutation sites, the yield can reach 5.91 g / L, the bottleneck problem of low catalytic efficiency of sialyltransferase is effectively solved, and an enzyme element with excellent performance is provided for high-efficiency and low-cost biological manufacturing of 3'-SL.

The invention relates to the technical field of catalyst materials, and particularly discloses a high-stability hydrogenation catalyst and a preparation method thereof. The invention relates to a preparation method of a high-stability hydrogenation catalyst, which comprises the following steps: preparing a hollow porous microsphere as an inner core from amino-terminated hyperbranched polyaryletherketone and polyvinyl alcohol, and then coating the porous microsphere with a mesoporous silicon dioxide intermediate layer by a sol-gel method; and finally, forming an Mg-Al hydrotalcite layer on the outermost side through a coprecipitation method, dipping and modifying with La (NO3) 3 and Ce (NO3) 3 solutions to obtain a catalyst carrier, dipping the catalyst carrier in an active metal dipping solution, and drying to obtain the catalyst. The high-stability hydrogenation catalyst provided by the invention has excellent mechanical properties and more reaction active sites, has high catalytic activity and catalytic efficiency, and is relatively long in catalytic life.

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 discloses preparation of a high-performance carbon matrix embedded iron-based catalyst based on a metal organic framework precursor and application of the high-performance carbon matrix embedded iron-based catalyst in reverse water-gas shift reaction. In the preparation process, commercially available 1, 3, 5-trimesic acid iron (the chemical formula is C9H3FeO6, abbreviated as Fe-BTC) is selected as a raw material, pyrolysis treatment is carried out in an argon atmosphere, then air passivation is carried out, and finally the high-performance carbon matrix embedded iron-based catalyst based on the metal organic framework precursor is successfully prepared. The MOF-600 has excellent performance in many catalysts, the carbon dioxide production rate reaches 24.0 mmol CO.gcat <-1 >. S <-1 > at the temperature of 400 DEG C in a reverse water gas shift reaction, the performance is remarkably superior to that of an existing non-noble metal catalyst, and extremely high catalytic efficiency and application potential are shown.

The invention discloses a sweat uric acid and glucose sensor based on a carbon nanotube (CNT) enhanced electrochemical platform, and aims to solve the sensitivity challenge of low-concentration biomarker detection in sweat. The enzyme is covalently immobilized on the CNT through an EDC / NHS chemical method, so that the catalytic efficiency, the electron transfer speed and the sensor stability are remarkably improved, and the ultralow detection lower limit of uric acid and glucose is realized. According to the device, uric acid, glucose and pH sensing functions are integrated on a single wearable platform, efficient flowing and rapid updating of sweat are ensured through a radiation symmetry microfluid design optimized through finite element analysis, and real-time biomarker monitoring is supported. The material innovation (such as CNT-enzyme complex) and fluid dynamics optimization of the invention overcome the key problem in the field of wearable biosensing, and provide an extensible solution for the next generation of non-invasive health monitoring.

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 relates to the field of nano-enzymes, in particular to a nano-enzyme, a preparation method and a method for detecting glucose by using the nano-enzyme. The nano-enzyme comprises a carrier and platinum nano-particles coated on the surface of the carrier, and the carrier is oxidized nano-diamond particles with the particle size of 20-30 nm. The core structure of the nano-enzyme, namely a composite system of the carrier and the platinum nano-particles, is defined, the platinum nano-particles serve as a metal nano-material with excellent catalytic performance and are a core component for simulating peroxidase activity, the size of the oxidized nano-diamond carrier is controlled to be 20-30 nm, the dispersity of the material is guaranteed, and the catalytic activity of peroxidase is improved. And the catalytic efficiency of the composite system can be further improved through a size effect. According to the structural design, the problems of insufficient catalytic activity and poor stability of a single nano material are solved through the synergistic effect of the carrier and the load component, and a material foundation is laid for subsequent efficient glucose detection.

The invention relates to a method for degrading nitrobenzene pollutants by using a humus-synergistic enhanced Fenton system, which comprises the following steps: adding a peroxide oxidant, a Fe (III) catalyst and a water-soluble organic reducing agent with Fe (III) reducing capacity into soil containing nitrobenzene pollutants, uniformly mixing to form a Fenton system, adding humus, and uniformly mixing to form the nitrobenzene pollutants. Mixing and reacting to obtain the soil for degrading the nitrobenzene pollutants. Compared with the existing Fenton technology, the method has the advantages that the overall catalytic efficiency can be improved, the initial pH does not need to be adjusted, and the method is green, safe and environmentally friendly.

The invention relates to the technical field of gene engineering, in particular to a glycosyl transferase mutant, a sucrose synthase mutant and application of the glycosyl transferase mutant and the sucrose synthase mutant in synthesis of rebaudioside M. Wild glycosyl transferase and wild sucrose synthase are modified according to a directed evolution theory to obtain a glycosyl transferase mutant and a sucrose synthase mutant. Rebaudioside M is obtained by catalyzing rebaudioside D through a glycosyl transferase mutant and sucrose synthase mutant co-expression strain, and the catalytic efficiency is superior to that of a wild enzyme. The rebaudioside M is obtained by completely catalyzing 110 g / L of rebaudioside D through the co-expression strain of the glycosyl transferase mutant and the sucrose synthase mutant, only 20 h is needed, the conversion rate reaches 97%, the yield of the rebaudioside M reaches 122 g / L, the raw material conversion rate and the yield of the rebaudioside M are effectively increased, and meanwhile the synthesis time is shortened.

The invention relates to the technical field of organic synthesis, in particular to a synthesis method and application of functional caprolactam and functional nylon-6. The synthesis method comprises the following steps: in the presence of a catalyst and a solvent, enabling amino caprolactam and / or a derivative thereof to contact and react with benzaldehyde, so as to obtain functional caprolactam which is bis (benzyl) amino caprolactam, wherein the reaction conditions are as follows: the temperature is 150-350 DEG C; the hydrogen pressure is 0.1 to 10 MPa; the time is 5-15 hours. The synthesis method not only has the advantages of high reaction efficiency, high catalytic efficiency, adjustable target product selectivity and the like, but also simplifies process conditions, and realizes green large-scale production.

The invention relates to the technical field of organic synthesis, in particular to a method for homogeneous catalytic synthesis of dimethyl carbonate by using a liquid separation method to separate a catalyst, which comprises the following steps: by using 0.3-15% long-chain tertiary amine as a homogeneous catalyst, carrying out homogeneous reaction on cyclic carbonate and methanol in a mass ratio of 1: (1.2-5.5) at 60-80 DEG C for 4-7 hours. And after the homogeneous transesterification reaction is completed, carrying out atmospheric distillation on the reaction mixture, and collecting fractions to obtain the target product dimethyl carbonate. Carrying out liquid separation on the heterogeneous atmospheric distillation residual liquid, and collecting a lower-layer material to obtain a by-product; and the collected material is a catalyst which can be directly recycled subsequently. The dimethyl carbonate synthesis method provided by the invention has the characteristics of high catalytic efficiency, easy catalyst separation, environmental protection, energy saving and the like.

The invention discloses NnLuz and NnH3H protein mutants and an application of the NnLuz and NnH3H protein mutants in enhancing the bioluminescence intensity of fungi or plants. According to the method disclosed by the invention, core enzymes NnLuz and NnH3H in a fungus bioluminescence pathway are optimized through rational design, and the catalytic efficiency and the luminous intensity of a bioluminescence system are remarkably improved. Experiments prove that 1) the luminous intensity of the NnLuz [delta] N19v2 (I103T / L167K double mutant) in yeast and plants is remarkably superior to that of a reported NnLuzv4 mutant and is 3-4 times that of the reported NnLuzv4 mutant, 2) the catalytic efficiency of the NnH3Hv3 (K307T mutant) is improved by more than 2 times, the luminous stability is remarkably enhanced, and 3) when the NnLuz [delta] N19v2 and the NnH3Hv3 are cooperatively expressed, the luminous intensity of the system reaches the optimal level, and the self-luminous plant with remarkably enhanced luminescence is created.

The invention provides an oxygen vacancy defect carbon nitride anchored iron atom cluster catalyst and a preparation method and application thereof, and belongs to the technical field of catalysts. Iron atoms are anchored in a carbon nitride (Ov-C3N4) structure containing oxygen vacancy defects in a cluster form, and Fe-Ov-C defect bonds are formed between the oxygen vacancy defects in C3N4 and iron atom clusters to stabilize the iron atom clusters, so that the problem of thermodynamic instability of the catalyst is solved while higher atom utilization efficiency is obtained; the Fe-Ov-C defect bond atoms can reasonably regulate and control the electronic structure of the center of an iron cluster d band, so that the catalytic activity and the cycling stability are greatly enhanced; besides, iron atom clusters and persulfate act to cause O-O bond breakage, non-free radical singlet oxygen is formed, and the problem that the catalytic efficiency is sharply reduced due to free radical annihilation in a complex water environment can be effectively solved.

The invention discloses a piezoelectric effect excitation method and application thereof. The piezoelectric effect of piezoelectric catalytic material particles is excited by applying mechanical stress to the piezoelectric catalytic material particles through rotational flow oscillation. According to the piezoelectric effect excitation method provided by the invention, the piezoelectric effect of the piezoelectric catalytic material is excited by adopting rotational flow oscillation, the excitation effect on the piezoelectric effect of the piezoelectric catalytic material particles in the rotational flow field can be realized through relatively low energy input, and no matter how large the reactor exists, the piezoelectric effect can be excited. All the piezoelectric catalytic particles in the rotational flow field can be subjected to large rotational flow oscillation mechanical stress, so that the piezoelectric effect of the piezoelectric catalytic material particles in the rotational flow field in the reactor can be effectively excited, the catalytic efficiency of the piezoelectric catalytic material particles is improved, and a foundation is laid for large-scale application of piezoelectric catalytic materials.

The invention discloses a method for biosynthesizing epigallocatechin gallate glucoside, and belongs to the technical field of biocatalytic synthesis. According to the method, a sucrose phosphorylase mutant is adopted as a catalyst, the sucrose phosphorylase mutant is subjected to single-point mutation or combined mutation on the basis of an amino acid sequence SEQ ID NO.1, and the enzyme activity of the sucrose phosphorylase is improved through mutation; the mutant is utilized to realize efficient catalytic synthesis of epigallocatechin gallate glucoside, and in the whole catalytic process, the synthesis method is mild in condition, simple to operate, short in reaction time and high in catalytic efficiency, and has a good application prospect.

The invention relates to the technical field of biological catalysis, and discloses an L204A mutant enzyme for preparing rebaudioside I. The enzyme is obtained by the following mutations generated by UGT76G1: L204A: leucine of the 204 amino acid sequence of UGT76G1 mutates into alanine; the high-efficiency in-vitro enzymatic preparation of the rebaudioside I (RI) is realized for the first time, the catalytic efficiency of the rebaudioside I (RI) is improved by more than 7 times (from about 7% to more than or equal to 50%) compared with that of an original enzyme, the high-efficiency performance can be stably maintained under different scales of 10mL to 5L, a solid foundation is laid for industrial application of the RI, and the preparation method is simple, controllable in process condition and suitable for popularization and application.

The invention relates to the technical field of enzyme engineering, in particular to an acylase mutant and a biosynthesis method of (R)-2-aminobutanol.The acylase mutant comprises at least one of mutation of the following sites relative to wild type acylase with the amino acid sequence being SEQ ID NO: 1: T106, A625 and S413. The acylase mutant disclosed by the invention is used for synthesizing (R)-2-aminobutanol through biological catalysis, and the reaction route is as follows: the catalytic efficiency of a product is remarkably improved by the mutant, and the ee value of a chiral product is improved; according to the synthesis method, the problem of chiral resolution in the prior art is solved, the production cost is reduced, and pollution is reduced.

The invention discloses a high-stability carbonyl reductase mutant and application of the high-stability carbonyl reductase mutant in chiral alcohol synthesis. An amino acid sequence as shown in SEQ ID NO.2 is mutated as follows: 20th leucine is replaced by any one of lysine, threonine, aspartic acid or isoleucine, and / or 55th leucine is replaced by any one of methionine, serine, lysine or isoleucine, and / or 55th leucine is replaced by any one of methionine, serine, lysine or isoleucine. Compared with a wild type enzyme, the stability of the obtained mutant is remarkably improved, particularly, single-point mutants Mut-L20I and Mut-L55I and a combined mutant Mut-L20I-L55I show excellent relative enzyme activity, thermal stability and substrate tolerance. The mutant has high catalytic activity and stability to various chiral alcohols, has the advantages of high catalytic efficiency, high thermal stability, strong substrate tolerance, easiness in fermentation production and the like, and is suitable for industrial application of enzymatic synthesis of chiral alcohols.

The invention discloses a preparation method of elastin peptide, and relates to the technical field of natural elastin extraction.The preparation method comprises the following steps that S1, animal blood vessels are cleaned, subjected to impurity removal, cut into blocks and minced; s2, the diced and minced animal blood vessels are soaked in alkali liquor for degreasing, the animal blood vessels are fished out and cleaned after degreasing, water is added after cleaning, pulping is conducted, slurry is obtained, and the pH of the slurry is adjusted to 7.5-8.5; s3, adding elastinase and trypsin into the pulp, and performing enzymolysis to obtain enzymatic hydrolysate; s4, sequentially performing high-temperature enzyme deactivation, vacuum concentration, purification, refining and spray drying on the enzymatic hydrolysate to obtain powdery elastin peptide. The trypsin and elastinase adopted in the invention belong to basic proteins, can decompose proteins under alkaline conditions, and have the characteristics of high catalysis efficiency, action specificity, activity adjustability, diversity and the like.

The invention discloses a preparation method of a catalytic membrane for organic wastewater treatment, which comprises the following steps: dissolving polyvinylidene fluoride (PVDF), a pore-forming agent and plant polyphenol in an organic solvent, and stirring to obtain a membrane casting solution, wherein the PVDF accounts for 12-20%, the pore-forming agent accounts for 1-8%, and the plant polyphenol accounts for 1-6%; standing and defoaming the membrane casting solution, blade-coating the membrane casting solution on a support body to form a membrane, and performing phase inversion in a water bath to obtain the plant polyphenol modified PVDF membrane; and immersing the membrane in a 3-10 mmol / L metal chloride aqueous solution, and reacting at 40-80 DEG C for 6-48 hours, so that metal ions and polyphenol are coordinated and crosslinked, and a metal-polyphenol network layer is formed on the surface of the membrane and the inner walls of membrane pores, thereby obtaining the catalytic membrane. The catalytic membrane can activate peroxymonosulfate (PMS) and synergistically degrade organic pollutants in water under a differential pressure filtration working condition, active sites are anchored stably, metal precipitation is reduced, and flux and catalytic efficiency are both considered.