707results about How to "High catalytic efficiency" patented technology

The invention belongs to the technical field of polyester recycling, and relates to a method for efficiently producing terephthalate by depolymerizing waste polyester through carbonic ester, which comprises the following steps: depolymerizing waste polyester, carbonic ester and a catalyst under the protection of nitrogen or inert gas and solvent-free conditions, a is more than one of zinc acetate, sodium acetate, potassium chloride, lithium chloride, potassium carbonate, sodium carbonate, ethylene glycol antimony, antimony trioxide, antimony acetate, ethylene glycol titanium and titanium dioxide, and B is sodium ethoxide. The method solves the problems of limited conversion of the waste polyester chemical recovery monomer and long production process in the prior art, obviously improves the catalytic efficiency and the depolymerization speed through the compound catalyst, simplifies the depolymerization process, reduces the energy consumption, and is beneficial to industrial application.

The invention discloses a glycosyl transferase mutant for synthesizing rebaudioside M and a synthesis method of rebaudioside M, and belongs to the technical field of gene engineering. The glycosyl transferase mutant for synthesizing the rebaudioside M is a glycosyl transferase UGT76G4 mutant and / or a glycosyl transferase UGT91C1 mutant, and the glycosyl transferase mutant is a glycosyl transferase UGT76G4 mutant. The glycosyl transferase UGT76G4 mutant is obtained by mutation of an amino acid sequence as shown in SEQ ID NO: 1: 85th amino acid is mutated into R from L, and 90th amino acid is mutated into G from I; the glycosyltransferase UGT91C1 mutant is obtained by mutating an amino acid sequence shown in SEQ ID NO: 3 as follows: the 204th amino acid is mutated into A from L, the 208th amino acid is mutated into A from F, and the 380th amino acid is mutated into D from G. The mutant can realize efficient catalytic synthesis of rebaudioside M, and the yield of rebaudioside M synthesized by an enzymic method is improved.

The invention discloses a fusion enzyme capable of efficiently degrading PET (polyethylene terephthalate) plastic and application of the fusion enzyme. The invention provides a recombinant fusion enzyme. The recombinant fusion enzyme comprises a mutant KL-MHETase of thermophilic carboxylesterase Est30 and a PET (Polyethylene Terephthalate) degrading enzyme FAST-PETase, the amino acid sequence of the mutant KL-MHETase of the thermophilic carboxylesterase Est30 is as shown in SEQ ID NO. 3; the amino acid sequence of the FAST-PETase is as shown in the 284th to 546th amino acids of SEQ ID NO.1 (Sequence Identifier Number 1). The fusion enzyme is used as a biocatalyst, the activity of catalyzing hydrolysis of MHET at 50 DEG C is 52.6 times that of FAST-PETase, and the fusion enzyme has high enzyme activity and thermal stability. PET degradation is catalyzed at the temperature of 50 DEG C, the conversion rate of PET is 90% after 48 hours of reaction, and meanwhile, the TPA content in the product is close to 100%.

The invention discloses a p-methyl benzyl chloride production process and a production system thereof, p-xylene side chains and chlorine are subjected to a gas phase substitution reaction under micro negative pressure and visible light catalysis to generate crude methyl benzyl chloride and hydrogen chloride, and 99.0% methyl benzyl chloride, a small amount of benzyl dichloride and 31% hydrochloric acid are respectively generated through rectification and absorption; the device consists of four working sections of chlorination, rectification, hydrochloric acid absorption and distillation. According to the method, the defects in the prior art are overcome, on one hand, chlorine is introduced, and an aromatic ring chlorination reaction is carried out under visible light catalysis; on one hand, a supported catalyst filler is arranged at the bottom of a chlorination tower, and a zeolite molecular sieve modified by long-chain alkylsilane and supported by metal salt is used as a catalyst to catalyze chloromethylation reaction, on the other hand, the hydrophobicity of the modified catalyst is obviously enhanced, and meanwhile, the density of acidic sites is not reduced; the contact opportunity of the catalyst and a reaction substrate is greatly increased, and the catalytic efficiency of the catalyst is improved.

The invention discloses a high-activity and high-thermal-stability MHET hydrolase mutant and application thereof. The invention provides a mutant protein of thermophilic carboxylesterase, which is shown as 1) or 2): 1) the protein shown as 1) is a protein obtained by mutating amino acid residues at the 130th site and the 171th site of wild thermophilic carboxylesterase shown as SEQ ID NO.2 or a sequence corresponding to the SEQ ID NO.2 and keeping other amino acid residues unchanged; (2) the protein is obtained by mutating amino acid residues at the 127th site, the 130th site and the 171th site of wild thermophilic carboxylesterase and keeping other amino acid residues unchanged. Experiments prove that the activity of the modified mutant for catalyzing MHET hydrolysis at the temperature of 50 DEG C is improved by 95 times compared with that of a wild type, and the modified mutant has higher enzyme activity and thermal stability and is the first enzyme capable of efficiently catalyzing MHET hydrolysis at the temperature of 50 DEG C at present.

The invention relates to a catalyst for ethylene oxide ring-opening polymerization and a preparation method thereof, and belongs to the technical field of high polymer material synthesis, and the catalyst is a composite structure based on a silicon dioxide nanoparticle loaded bimetal organic complex; a modified nitrogen-containing polydentate ligand is prepared by adopting a special method, is coordinated with metal ions through covalent bonds and is loaded on silicon dioxide nanoparticles; by utilizing the high dispersity and stability of the silicon dioxide nanoparticles and the synergistic catalytic effect of the bimetal organic complex, the catalytic effect is effectively improved, the polymerization process is accelerated, the polymerization stability is enhanced, the polymerization molecular weight is improved, and the distribution is narrow.

The invention discloses a Fe-MOF derivative / biochar nano composite material as well as a preparation method and application thereof, and belongs to the field of degradation of organic pollutants in a water body. The invention aims to solve the problems of unstable structure, easy agglomeration and the like at high temperature. The preparation method comprises the following steps: by taking an Fe-MOF derivative as a precursor and charcoal as a carrier material, carrying out in-situ synthesis on Fe-MOF, and carrying out high-temperature calcination on the surface of charcoal (BC). The metal carbon-based composite material prepared by the method shows excellent catalytic performance in catalytic degradation of tetracycline in a water body. Meanwhile, the prepared multiphase composite catalytic material has good stability and cycle performance.

The invention discloses a tyrosine phenol lyase mutant and application of the tyrosine phenol lyase mutant in synthesis of levodobar. The tyrosine phenol lyase mutant is obtained by carrying out site-specific mutagenesis on the basis of wild type tyrosine phenol lyase. The mutant obtained through transformation can transform more substrates, the yield is also obviously improved, and the method is suitable for industrial production of levodopa.

The invention relates to the technical field of sulfur hexafluoride gas thermocatalytic conversion, and discloses a supported catalyst for SF6 thermocatalytic conversion and a preparation method thereof, and the preparation method comprises the following steps: titanium dioxide is supported on the surface of SiC in a nanoscale particle form, and the mass ratio of titanium dioxide to silicon carbide is 1: 5. The catalyst and the preparation method provide possibility for harmless treatment of SF6 under milder conditions, and the provided preparation method has the advantages of high loading efficiency, simple preparation device, reduction of the preparation cost, increase of the effective reaction area of the catalyst, and good application potential and popularization prospect.

The invention belongs to the technical field of grease modification and lipid deep processing, and particularly relates to a method for enriching n-3 polyunsaturated fatty glyceride by an enzymic method. According to the method, alkyl-modified hollow mesoporous silica spheres are used as an immobilized enzyme carrier and an emulsifier, grease rich in n-3 polyunsaturated fatty acid is used as a raw material in a stable Pickering emulsion system, saturated fatty acid and monounsaturated fatty acid are selectively hydrolyzed by lipase, and polyunsaturated fatty glyceride is enriched. The method has the characteristics of fast reaction, high yield, wide substrate application range and reusability of the immobilized enzyme, and the content of polyunsaturated fatty acid in the polyunsaturated fatty glyceride reaches 58.05-90.53%.

The invention discloses a P450 mutant and application thereof in synthesis of calcifediol, and belongs to the technical field of bioengineering. According to the present invention, the P450 enzyme mutant enzyme is constructed, and the single plasmid three-enzyme co-expression system of the redox partner and the cofactor cycle enzyme is constructed, such that the sufficient electron transport chain is provided for the P450 enzyme, and the calcifediol can be efficiently synthesized under the mild condition by using the vitamin D3 as the substrate; the conversion rate of calcifediol can reach 63.1%, and the conversion rate of the reaction is greatly improved. By adopting the method disclosed by the invention, the catalytic efficiency of the catalyst is improved, and the reaction cost is reduced.

The invention provides a preparation device and process of electronic-grade silane. According to the preparation device, a first disproportionation reaction is carried out on the basis of the first reactor, dichlorosilane is rectified and separated to serve as a raw material for a second disproportionation reaction, silane can be obtained on the basis of cheap trichlorosilane and a catalytic reagent, and electronic-grade silane can be obtained on the basis of traditional purification after rectification; based on heat exchange between tower top materials of the rectifying tower I and a tower kettle reboiler of the rectifying tower II, differential pressure thermal coupling integration is realized, condensing equipment and operation steps can be omitted, energy consumption is reduced, and the defects of high preparation cost and high energy consumption of a silane preparation device in the prior art are overcome.

The invention relates to the technical field of biology, in particular to application of N-terminal truncated 8-isopentenyl transferase in production of 8-isopentene kaempferol. The invention provides the N-terminal truncated 8-isopentenyl transferase, and the N-terminal truncated 8-isopentenyl transferase can be used for carrying out isopentenylation on kaempferol to generate 8-isopentene kaempferol. Specifically, the saccharomyces cerevisiae is used as a chassis, under the condition that kaempferol is exogenously added, through overexpression of 8-isopentenyl transferase, biosynthesis of 8-isopentenyl kaempferol in the saccharomyces cerevisiae is realized, and meanwhile, a foundation is laid for subsequent biosynthesis of icaritin. The invention provides a novel reference scheme for biosynthesis of flavonoid compounds.

The invention relates to the technical field of biology, in particular to a leucine dehydrogenase mutant and application thereof. According to the leucine dehydrogenase mutant and the application thereof provided by the embodiment of the invention, wild leucine dehydrogenase is subjected to mutation screening to obtain the leucine dehydrogenase mutant with an amino acid sequence as shown in SEQ ID NO: 1 or SEQ ID NO: 2, the catalytic efficiency of asymmetric reductive amination of a prochiral alpha-keto acid compound is improved, and the thermal stability of the leucine dehydrogenase mutant is improved; the synthesis efficiency of the L-amino acid is favorably improved.

The invention relates to an epoxy-terminated polyurethane flexibilizer for bridge and tunnel pavement, and a preparation method and a use method thereof, and the flexibilizer is prepared by terminating a polyurethane prepolymer through an epoxy group of an epoxy compound under the catalytic action of nano-modified imidazole; wherein an epoxy group reacts with an NCO group at the end part of a polyurethane prepolymer, and a five-membered ring structure with high cohesive energy is introduced into a polyurethane molecular chain. A main chain of the epoxy-terminated toughening agent contains a five-membered ring structure, and the epoxy-terminated toughening agent is prepared from an epoxy group and an isocyanate group through catalysis of nano-modified imidazole at a relatively low temperature. Due to the fact that the cohesive energy of the five-membered ring is high, the steric hindrance effect is large, good high and low temperature stability is achieved, and the damping temperature range is wide. And after being cured, the curing agent has the properties of high-temperature rutting resistance, medium-temperature fatigue resistance, low-temperature crack resistance and the like, and the problem of insufficient toughness of an epoxy mixture in conventional pavement is solved.

The invention discloses a heme oxygenase mutant and bilirubin efficiently synthesized by a multienzyme coupling system of the heme oxygenase mutant, and belongs to the field of biological catalysis engineering. The invention provides a heme oxygenase mutant which is used for catalyzing heme to synthesize biliverdin. Coupling biliverdin reductase to catalyze biliverdin to synthesize bilirubin; cytochrome P450 reductase is introduced to provide electrons; removing competitive binding of the by-product to the substrate heme by carbon monoxide dehydrogenase; formate dehydrogenase is used for in-situ regeneration of coenzyme, and bilirubin is efficiently synthesized through a one-pot method. According to the heme oxygenase mutant, the two core enzymes are coupled with three external assistant enzymes, recombinant escherichia coli is constructed, heme is catalyzed, exogenous NADPH does not need to be added, and the yield of bilirubin within 4 h reaches 1611 mg / L and reaches the bilirubin synthesis level which is reported at present and has the highest yield and the shortest time. According to the technology, resource limitation is relieved, the synthesis method is easy to operate and high in yield, and efficient and green synthesis of bilirubin is achieved.

The invention relates to a membrane electrode and a preparation method thereof and a PEM electrolytic bath, the membrane electrode comprises a proton exchange membrane and functional layers located on the two sides of the proton exchange membrane, each functional layer comprises a gas diffusion layer and a catalyst layer, the catalyst layer is located between the proton exchange membrane and the gas diffusion layer, and the gas diffusion layer and the catalyst layer are each of a porous structure; a conductive structure is arranged between the gas diffusion layer and the catalyst layer, and the conductive structure exists in the form of a layered structure or a dotted structure. According to the membrane electrode disclosed by the invention, the gas diffusion layer and the catalyst layer form a multi-stage porous structure, so that the membrane electrode can reduce the dosage of a catalyst under the same catalytic activity, reduce the material cost of the catalyst and enhance the binding capacity between the catalyst layer and the gas diffusion layer. The conductive structure improves the conductivity of the membrane electrode, reduces the corrosion of the gas diffusion layer in the long-time working process, and improves the bonding performance between the gas diffusion layer and the catalyst layer.

The invention provides a preparation method of an MXene-based alkaline electrolytic water hydrogen production electrode. The preparation method comprises the following steps: 1, pretreatment of a base material: cleaning impurities on the base material, drying, and carrying out sand blasting roughening treatment; secondly, first metal powder and second metal powder are weighed and mixed according to a certain proportion to be guided into a powder mixing machine, vacuum drying is conducted after mixing treatment, third metal powder is prepared, the first metal powder is MAX phase powder, and the second metal powder is one or more of metal simple substances or alloys used for water electrolysis hydrogen production; thirdly, third metal powder is deposited on the surface of the pretreated base material through the plasma spraying technology, and a composite coating is obtained; 4, immersing the base material treated in the step 3 into an activation solution for activation; 5, after activation is finished, the base material is taken out and dried, and then the electrode is obtained.The method optimizes the conductivity and hydrophilicity of the electrode, and the diversity of the morphology of a plasma spraying electrode coating is improved.

The invention relates to the field of scavengers, in particular to a copper-based urea crystal scavenger for a vehicle and a preparation method of the copper-based urea crystal scavenger. The automotive copper-based urea crystal scavenger provided by the invention is prepared from the following raw materials: a copper-based catalyst, a surfactant, a foaming agent, a dispersing agent, a reducing pigment and deionized water, wherein the copper-based catalyst comprises copper acetate, the surfactant comprises AEO-10 and MOA-3PK, and the reducing pigment comprises methylene blue; the prepared automotive copper-based urea crystal scavenger is convenient to use, excellent in urea crystal melting effect and short in effective mileage, the environmental protection property of automobile running can be obviously improved after the automotive copper-based urea crystal scavenger is used, and meanwhile the effect of reducing the use cost of an automobile is remarkable.

The invention provides a biochar loaded sulfur modified zero-valent iron material and application thereof in groundwater remediation, and particularly relates to the technical field of inorganic materials. According to the biochar-loaded sulfur-modified zero-valent iron material, sulfur-modified zero-valent iron is loaded in a porous structure of biochar; the sulfur modified zero-valent iron has a core-shell structure; wherein the inner core of the core-shell structure is zero-valent iron, and the outer shell of the core-shell structure is iron sulfide. According to the biochar-loaded sulfur-modified zero-valent iron material provided by the invention, a sulfide layer is formed on the surface of zero-valent iron, so that a zero-valent iron core is prevented from being in direct contact with water or dissolved oxygen, and the durability of the zero-valent iron core is improved. Delocalized electrons in the sulfide layer promote the electron transfer process, and the catalytic performance of the material is enhanced. The biochar loaded sulfur modified zero-valent iron material provided by the invention is high in stability and wide in application range. Due to the multifunctionality of the material, the material has potential application value in a plurality of fields such as environmental restoration and pollutant degradation.

The invention provides an RNA polymerase variant and application thereof, and relates to the technical field of biology. Wild type T7 RNA polymerase is modified to obtain the T7 RNA polymerase variant, the enzyme specific activity of the T7 RNA polymerase variant is remarkably improved compared with that of the wild type T7 RNA polymerase, the addition amount of the polymerase in the in-vitro transcription reaction process can be reduced, and the cost is saved; in addition, the mutant also effectively reduces the generation of incomplete fragment impurities, and the mRNA integrity is significantly improved to 99%. The invention further provides a method for preparing RNA through in-vitro transcription.

The invention discloses a rare ginsenoside dammadienol synthetase and an application of the rare ginsenoside dammadienol synthetase in preparation of dammadienol. The dammadienol synthetase is identified for the first time in the research, a metabolic network of a saccharomyces cerevisiae host cell is modified through a metabolic engineering strategy, genes which do not exist in the host cell are introduced into an engineering strain for heterologous expression, the host cell is changed from nothing to existence, and the dammadienol engineering strain is constructed. In addition, through homologous modeling, key catalytic pocket searching and key enzyme gene site-directed mutagenesis modification, enzyme catalysis efficiency is improved, efficient synthesis of dammadienol is achieved, the problem that natural sources of the rare ginsenoside are insufficient is solved, green synthesis and sustainable utilization of the rare ginsenoside are promoted, and the method is suitable for industrial production. And a foundation is laid for subsequent construction of rare ginsenoside cell factories.

The invention discloses salt-tolerant xylanase and application thereof, and relates to the technical field of biology. The amino acid sequence of the salt-tolerant xylanase is as shown in SEQ ID NO: 1. According to the invention, a new xylanase gene xynaes is separated from a metagenome of Xinjiang Aiding Lake, and the xylanase belongs to the GH10 family and has low homology with reported xylanase. The recombinant xylanase has high activity and tolerance at a high temperature, has good performance in an alkaline environment, has high tolerance to various metal ions, quickly loses activity under SDS treatment, and should be prevented from being in contact with SDS in industrial production.

The invention discloses a method for preparing engineering bacteria capable of improving the catalytic efficiency of glucuronic acid and a method for converting glucuronic acid, which comprises the following steps of: through carrier construction, mutant construction and expression strain preparation, adding inositol transport protein to an inositol oxidase expression strain, and mutating lazy acid at the 57th site of inositol oxidase into alanine, the catalytic efficiency of the new genetic engineering strain on substrate inositol within the same time is improved by 43%, the substrate can be converted into a product glucuronic acid more quickly, and the risk that inositol oxidase is low in stability and incomplete in catalysis is greatly reduced.

The invention relates to the field of genetic engineering and immobilized enzymes, in particular to a sucrose isomerase recombinant as well as a construction method and application thereof. Wild type sucrose isomerase (Sase) from dispersed pantoea is subjected to molecular modification, fusion expression is performed after screening of affinity peptide ligands, the specific enzyme activity of the obtained sucrose isomerase recombinant is 88% higher than that of sucrose isomerase, the enzyme activity level of the sucrose isomerase recombinant is remarkably improved, and the specific catalysis efficiency of the sucrose isomerase recombinant on a sucrose substrate is improved; and reference is provided for improving molecular modification of other enzymes. The sucrose isomerase recombinant has good thermal stability, and finally, research on embedding system optimization is performed on one-step purification and immobilization of SIase, so that the affinity directional immobilized enzyme microspheres which have high hardness and strength and can effectively reduce leakage or loss of enzyme molecules are prepared. The reusability of the sucrose isomerase recombinant is obviously improved.

The invention discloses a synthesis method of a 9, 9-di-n-octylfluorene copolymer, which comprises the following steps: under the action of an N-heterocyclic carbene palladium complex and organic alkali, reacting 9, 9-dioctylfluorene-2, 7-bis (boronic acid pinacol ester) with 2, 5-dichloropyridine to obtain the 9, 9-di-n-octylfluorene copolymer, and reacting the 9, 9-di-n-octylfluorene copolymer with the boronic acid pinacol ester to obtain the 9, 9-di-n-octylfluorene copolymer. The structure of the N-heterocyclic carbene palladium complex is as shown in a formula (I): # imgabs0 # formula (I); the 9, 9-di-n-octylfluorene copolymer is prepared through catalysis of the N-heterocyclic carbene palladium complex, the 9, 9-di-n-octylfluorene copolymer has the advantage of being high in catalysis efficiency, the 9, 9-di-n-octylfluorene copolymer with high molecular weight and narrow distribution can be obtained, and the problems that a phosphine ligand catalyst is large in toxicity and the like are solved; and the application of the 9, 9-di-n-octylfluorene copolymer in preparation of a hole transport layer of a perovskite solar cell is developed.

The invention relates to the field of bioengineering, in particular to application of integration sites as targets in production and / or preparation of icaritin, and the integration sites comprise one or more of a YPRC [delta] 15 site, a YORW [delta] 22 site, a HO site, a YNRC [delta] 9 site, a PDC5 site, a YCRW [delta] 12 site and a YMRW [delta] 15 site. The saccharomyces cerevisiae is used as a chassis cell, two-step conversion from kaempferol to icaritin is focused on, a novel method for enhancing synthesis of icaritin from the perspective of pathway engineering and enzyme engineering is provided, and an advanced strategy is provided for biosynthesis of flavonoid compounds and natural products.

The invention discloses an alumina-loaded molecular alkane dehydrogenation catalyst and a preparation method and application thereof. The preparation method comprises the following steps: (1) carrying out modification treatment on alumina balls; and (2) adding the modified alumina balls into a dissolved solution of a molecular catalyst, stirring, reacting until the supernatant is colorless, filtering, and drying to obtain the alumina-loaded molecular alkane dehydrogenation catalyst. The catalyst provided by the invention is used in a process for preparing olefin through dehydrogenation of straight-chain alkane, the alkane conversion rate can reach 21% or above, the catalyst is high in catalytic efficiency, good in selectivity and easy to recover, and the activity of the recovered catalyst is still high.

The present invention discloses a method for upgrading polyester materials to dicarboxylic acid esters and ethylene carbonate, and relates to the comprehensive utilization of waste resources and the cascade utilization of raw materials. The method uses multiple types of green ionic liquid catalysts to catalyze the methanolysis reaction of PET, and then dimethyl carbonate captures the generated ethylene glycol in situ, forms a five-membered cyclic ethylene carbonate through nucleophilic cyclization, pulls the reaction equilibrium to move forward, and completely depolymerizes PET waste. The products of the method of the present invention are dimethyl terephthalate and five-membered cyclic ethylene carbonate. The present invention can be used for the depolymerization and upgrading of waste PET materials, and can also be used for other similar polyesters, such as polyethylene succinate, polyethylene adipate and polyethylene 2,5-furan dicarboxylate, which are also suitable for the recovery strategy of the present invention, and the products are the corresponding dimethyl succinate, dimethyl adipate and 2,5-furan dicarboxylate.

The invention provides a process system and a process method for recycling a hexafluoropropylene oxide byproduct high-boiling residue, and relates to the field of fine fluorine chemical industry. The process system comprises a heat exchange device, a tubular pyrolysis reaction device, a carbonyl fluoride-trifluoroacetyl fluoride separation tower, a tubular cracking reaction device, a water washing device and an alkali washing device. According to the method disclosed by the invention, the industrial-grade carbonyl fluoride and trifluoroacetyl fluoride are prepared by catalytically pyrolyzing the hexafluoropropylene oxide by-product high-boiling residue; furthermore, a byproduct high-boiling residue of hexafluoropropylene oxide is subjected to complete catalytic cracking to obtain carbonyl fluoride, and a byproduct industrial hydrofluoric acid can be obtained. According to the process system and the process method, the hexafluoropropylene oxide byproduct is recycled into carbonyl fluoride, trifluoroacetyl fluoride and industrial hydrofluoric acid with high added values, harmlessness and recycling of the hexafluoropropylene oxide byproduct high-boiling residues are achieved, the utilization rate of fluorine atoms is 100%, and the process method is mild in reaction condition, economical and environmentally friendly.