435 results about "Enzyme catalysis" patented technology

The invention provides a saccharomyces cerevisiae engineering strain HYB05 capable of releasing astaxanthin in a controllable self-splitting manner. The saccharomyces cerevisiae engineering strain HYB05 is constructed by taking a basic strain for producing astaxanthin as a starting strain, introducing a coding sequence comprising cell wall lyase Lyc, a coding sequence of a signal peptide mutant F8A and a recombinant nucleic acid construct for expressing a regulatory element, and knocking out an SSD1 gene to relieve a translation inhibition effect. The cell wall lyase Lyc is found and disclosed by the inventor for the first time, and the amino acid sequence is shown as SEQ ID NO: 6; the amino acid sequence of the signal peptide mutant F8A is as shown in SEQ ID NO: 8. According to the engineering strain HYB05, by introducing the recombinant nucleic acid construct, the activation of the catalytic activity of cell wall lyase under specific conditions is realized, so that the cell wall of the saccharomyces cerevisiae is broken, and the astaxanthin synthesized by the saccharomyces cerevisiae is released. Compared with the prior art, the astaxanthin is produced through fermentation of the strain, the extraction steps are simplified, extraction of the astaxanthin in the yeast is achieved to the maximum extent, the yield of the astaxanthin is remarkably increased, and the technical effect is remarkable.

The invention discloses an enzyme catalytic synthesis method of a luliconazole chiral intermediate, which comprises the following steps: adding a recombinant escherichia coli wet cell for expressing alcohol dehydrogenase, a recombinant escherichia coli wet cell for expressing formate dehydrogenase, a buffer solution, a substrate, a cosolvent, ammonium formate and a coenzyme into a reaction container, reacting at 25-35 DEG C for 2-24 hours, extracting, separating, and carrying out rotary evaporation, thereby obtaining the luliconazole chiral intermediate. The luliconazole chiral intermediate is obtained; the substrate is 2, 2 ', 4'-trichloroacetophenone; the alcohol dehydrogenase is a mutant of AKR3. The method is mild in reaction condition, environmentally friendly, high in regioselectivity and stereoselectivity, high in conversion rate, high in chiral purity, small in enzyme dosage, low in preparation cost and suitable for industrial production.

The invention belongs to the technical field of enzyme catalysis, and particularly relates to a dehydrogenase mutant, a gene, an engineering bacterium and application, the dehydrogenase mutant is obtained through mutation of original dehydrogenase, the sequence of the original dehydrogenase is SEQ ID NO.1, and the mutation mode is that the 344 site is mutated from A to W, K, F, S or N, or the 130 site is mutated from H to T, W or F; the dehydrogenase mutation diagram provided by the invention has higher conversion rate, stronger specificity and faster reaction speed.

The invention discloses an integrated nano platform for bimodal detection and synergistic sterilization of pathogenic bacteria as well as a preparation method and application of the integrated nano platform, and belongs to the technical field of food safety. The platform is composed of a multifunctional nano probe (MPDA / Pd SA-DA-CDs / Apt) and a magnetic separation assembly (MNRs / PGA / AM). The probe integrates enzyme-like catalysis and photo-thermal performance and is used for generating colorimetric and photo-thermal dual-mode signals so as to realize high-sensitivity and high-reliability detection of pathogenic bacteria. The magnetic separation assembly is used for specifically capturing and enriching target bacteria and eliminating matrix interference. After detection is positive, the platform can immediately start secondary propulsion synergistic sterilization: firstly, the action distance is shortened through magnetic aggregation, and then pathogenic bacteria are efficiently inactivated and biological membranes are disintegrated by utilizing the synergistic effect of near-infrared laser excitation photothermal effect and active oxygen. According to the invention, the integration of detection and disinfection is realized, the operation is convenient, and the method has important application value in the fields of food safety and biomedicine.

The invention discloses an enzyme catalysis constant kcat prediction method and system based on multi-modal feature fusion, and the method comprises the steps: S1, obtaining an enzyme-substrate pair which comprises an amino acid sequence of a target enzyme and a chemical structure expression of a corresponding substrate; s2, inputting the amino acid sequence into a pre-trained protein language model, and carrying out average pooling treatment on hidden layer state vectors of amino acid residues in the sequence by the protein language model to obtain enzyme feature vectors for representing functional features of enzyme; s3, on the basis of the chemical structure representation of the substrate, coding the chemical structure through the set radius parameter and bit length parameter by adopting an extended connectivity chemical fingerprint algorithm to obtain a substrate feature vector for representing the structural features of the substrate; s4, splicing the enzyme feature vector and the substrate feature vector to obtain a fused feature vector; and S5, inputting the fusion feature vector into a random forest regression model, and outputting a predicted value of the catalytic constant kcat of the enzyme-substrate pair.

The invention provides a seawater soaking wound hydrogel dressing and a preparation method thereof, a drug-loaded nano system 4OI (at) ZIF-8 (at) PAD with a core-shell structure is constructed, an anti-inflammatory drug 4-octyl itaconic acid and zinc ions are jointly encapsulated in a ZIF-8 framework, and a polydopamine coating is wrapped, so that synergistic loading and controllable release of the drug and metal ions are realized. According to the dressing, dopamine modified hyaluronic acid is used as a matrix, a temperature-sensitive material and an enzyme catalysis cross-linking system are combined, stable gel can be rapidly formed in situ within 5 seconds, and the dressing has excellent tissue adhesion performance (the adhesion strength reaches 6.7 kPa). Experiments prove that the hydrogel dressing has the characteristics of broad-spectrum antibiosis, inflammation regulation and control and long-acting release. Animal experiments prove that the healing rate of seawater soaking wounds treated by the dressing on the twelfth day is as high as 95.7% and is remarkably superior to that of a commercial silver ion gel control group, scars are less after healing, and an efficient, safe and easy-to-implement scheme is provided for marine environment wound nursing.

The present invention relates to the technical field of organic synthesis, and specifically relates to a method for constructing the chirality of a pyran ring in Orforglipron by means of enzymatic catalysis, the method comprising the following steps: step S1, by using SM1 and SM2 as starting materials, carrying out a reaction under the action of a palladium catalyst and a ligand to obtain INT-1; step S2, under the catalysis of Pd / C, subjecting INT-1 to double bond hydrogenation reduction to obtain INT-2; step S3, in the presence of a solvent, a buffer salt system and enzymatic catalysis, subjecting INT-2 to hydrolysis and resolution to obtain a chirally pure intermediate INT-3; step S4, subjecting INT-3 to a Grignard reaction for cyclization, so as to synthesize a lactone intermediate INT-4; and step S5, subjecting INT-4 to reduction by means of Dibal-H, quenching same, performing extraction with dichloromethane, drying same with anhydrous sodium sulfate, and then performing reduction by means of triethylsilane to obtain a compound of general formula A. In the present invention, the chirality is constructed by means of enzymatic catalysis without the need of SFC resolution for separating isomeric impurities during the construction of the chirality, thereby reducing losses and improving yield, obtaining the target product at high yield and high chiral selectivity, and further saving expenses and reducing costs.

The invention provides an enzyme catalysis performance prediction method and system based on chemical reaction and a storage medium. The enzyme catalysis performance prediction method based on the chemical reaction comprises the following steps: inputting a to-be-detected sample; inputting the SMILES character string of the reaction in the to-be-tested sample into a pre-fine-tuned reaction encoder in a pre-trained VenusRXN model to obtain an atom embedding matrix formed by stacking all atom embedding vectors in a reaction compression graph of the reaction; inputting the atom embedding matrix and an enzyme sequence corresponding to the reaction in the to-be-detected sample into a reaction-protein joint encoder which is finely adjusted in advance in the VenusRXN model to obtain a reaction-protein joint CLS embedding vector; inputting the combined CLS embedding vector into a matching head, and calculating a matching score between the reaction and the corresponding enzyme sequence; and outputting the matching score.

The invention belongs to the technical field of synthesis and antibiosis of nano-enzyme catalysis systems, and discloses an enzyme catalysis system with a function of targeted inhibition of growth of streptococcus mutans as well as preparation and application of the enzyme catalysis system. The enzyme catalysis system with the targeted inhibition function on the growth of the streptococcus mutans is formed by loading AuNPs and PCN-22 (Fe) on a CMD molecular chain through in-situ growth, and the mass ratio of the AuNPs to the PCN-22 (Fe) to the CMD is (0.22%-0.33%) to (12.34%-21.79%) to (77.88%-87.44%). The cascade catalytic effect of the nano-enzyme is adjusted by regulating and controlling the carboxymethyl substitution degree of CMD, so that glucose in a decayed tooth pathological environment is efficiently catalyzed in one step to generate ROS, and damage to probiotics is reduced while the inhibition efficiency of pathogenic bacteria is improved.

The invention relates to the technical field of biological catalysis engineering, in particular to a method for improving the solubility of stevioside Reb M and Reb D through enzyme catalysis modification, which comprises the following steps: dissolving Reb M and Reb D with the purity of more than or equal to 90% in a buffer solution with the pH value of 4.0-8.0, adding a non-starch glycosyl donor and composite glycosyl transferase according to the enzyme-substrate mass ratio of 0.05-0.5, and optimizing the enzyme addition sequence to realize specific site modification; reacting for 6-24 hours under the conditions that the pH is 5.5-6.0 and the temperature is 60-85 DEG C, and controlling the proportion of DP2-3 to be 60-80%; hPLC sampling is carried out every 4-6 hours, and the unreacted substrate is less than or equal to 20%; the solubility of the product is greater than or equal to 25g / L, and the sweet taste of the product is pure. According to the method, the solubility of Reb M / Reb D is improved, the structure of a directional glycosylation controlled product is realized, and pure sweetness is reserved; the reaction is mild and controllable, enzyme inactivation is simple and free of residues, industrialization is easy, and stevioside application upgrading is promoted.

The invention discloses xylanase XynA00838, a truncated body of the xylanase XynA00838 for removing CBM1 and application of the xylanase XynA00838, and belongs to the technical field of microorganisms. The invention provides the XynA00838, the amino acid sequence of the truncation of the XynA00838 and the nucleotide sequence of the coding gene of the XynA00838, and provides characterization information, the XynA00838 and the truncation of the XynA00838 have obvious xylanase activity, and the specific enzyme activity of the truncation of the XynA00838 is obviously higher than that of wild type xylanase XynA00838 when six different plant polysaccharides are degraded, so that the XynA00838 and the truncation of the XynA00838 can be used for degrading various plant polysaccharides. When the truncated body degrades low-viscosity wheat arabinoxylan as a substrate, the specific enzyme activity reaches 4.46 + / -0.12 U / mg and is remarkably higher than that of wild type xylanase XynA00838. The CBM1 in the xylanase XynA00838 disclosed by the invention has a relatively good maintaining effect on the temperature stability of an enzyme catalysis module of the xylanase XynA00838. The truncated body XynA00838 delta CBM1 of the xylanase XynA00838 without the CBM1 has high enzyme activity and pH stability, so that the truncated body XynA00838 delta CBM1 has relatively great development and application potential, and a basic theoretical basis is provided for preparing a commercial feed enzyme preparation.

The application belongs to the field of chemical analysis, and particularly relates to a method for detecting LNT II synthesized by an enzyme catalysis process, comprising the following process: in the process of synthesizing an intermediate and / or end product of LNT II by an enzyme catalysis process, the reaction solution after inactivation and protein removal is detected by HPLC-UV-RI, and the detection result is quantitatively analyzed; the chromatographic condition of the HPLC-UV-RI detection is as follows: a HILIC column of a polymer matrix, a column temperature of 50-60 DEG C, a mobile phase A of acetonitrile, a mobile phase B of a potassium phosphate dibasic aqueous solution, a concentration of the potassium phosphate dibasic aqueous solution of 40-60 mmol / L, a pH value of 6.5-7.5, and a volume ratio of the mobile phase A to the mobile phase B of (65-75):(35-25). The method provided by the application can effectively separate and accurately quantify the substrate, intermediate, end product and the like in the reaction solution in the process of synthesizing LNT II by an enzyme catalysis process.

This invention provides a method for screening β-galactosidase inhibitors, belonging to the field of pharmaceutical technology. The first step of this method uses fluorescence sensing technology to rapidly identify natural products with β-Gal inhibitory activity. The principle is based on the fluorescence quenching property of p-nitrophenol (PNP) on sulfur quantum dots (SQDs); β-Gal catalyzes the hydrolysis of p-nitrophenyl-β-D-galactopyranoside (PNPG) to generate the specific product PNP; in the presence of β-Gal, PNPG can be enzymatically catalyzed to generate PNP, quenching the fluorescence of SQDs; when screened for β-Gal inhibitory activity, the fluorescence of SQDs can be restored. The second step uses affinity chromatography to capture components in samples with β-Gal inhibitory activity. This method involves immobilizing β-Gal on a support material, eluting with a solvent to obtain components that can bind to β-Gal, and then using liquid chromatography-mass spectrometry (LC-MS) to identify the components. This method can rapidly and accurately screen β-Gal inhibitors from natural products.

The invention relates to a flame-retardant skin-friendly polyurethane sponge with in-situ reaction and bio-enzyme catalysis synergism. The water-based polyurethane foam is prepared from the following components: polyether polyol, diphenylmethane diisocyanate or toluene diisocynate, a chain extender, a high-efficiency foam stabilizer, a high-efficiency composite catalyst, water and ethanolamine phosphate, ethanolamine phosphate is added into water in advance, and then all the raw materials are mixed for polymerization foaming; after curing, spraying a spraying liquid consisting of phosphoethanolamine, regenerated protein and transglutaminase to generate a nano protein film, and synchronously performing vacuum suction to keep sponge pores unblocked. The preparation method has the advantages that a small amount of ethanolamine phosphate is added before polymerization foaming to serve as a phosphorus-nitrogen synergistic flame retardant and also serve as a catalytic cross-linking agent to participate in a reaction during polymerization, biological enzyme is added for catalysis after curing is finished, and the skin-friendly PU sponge with excellent flame retardance is prepared through in-situ polymerization reaction and biological enzyme enzymatic polymerization cooperation, and the sponge performance is not affected; the raw materials of the flame retardant come from biomass products and are environment-friendly and safe.

The disclosure provides preparation and application of an anionic resin with high selective adsorption of ergothioneine, belonging to the field of biochemical engineering. A polyamine-type epoxy weak-base anionic resin is used as a carrier for the first time. Ni atoms are loaded onto the target resin carrier in the form of [NiCl4]2— ions, followed by in situ reduction and rinsing regeneration to prepare a metal Ni nanoparticle-loaded polyamine-type epoxy weak-base anionic resin. The preparation process is simple and the stability is good. The disclosure has strong selective adsorption for ergothioneine in fermentation broths and the facile elution. The disclosure can be widely applied in purification processes for ergothioneine preparation through fermentation and enzymatic catalysis.

The application provides a method for synthesizing benzimidazole Michael addition derivatives in a continuous flow reactor, and 2-methylbenzimidazole and alpha, beta-unsaturated olefins are used to catalyze the online synthesis of benzimidazole Michael addition derivatives in a microfluidic channel reactor by using a lipase Lipozyme RM IM. The method not only greatly shortens the reaction time, but also has high conversion rate; meanwhile, the Michael addition reaction of 2-methylbenzimidazole and alpha, beta-unsaturated olefins is catalyzed by using the economical lipase Lipozyme RM IM in methanol, the reaction cost is reduced, the post-processing step is simplified, and the method has the advantages of green environmental protection, economy and efficiency.

The invention discloses a method for synthesizing novel alkaloid by enzyme catalysis of tryptamine and alpha-ketoamide substances, and the method comprises the following steps: reacting a compound shown as a formula (A) with a compound shown as a formula (B) in the presence of isoviscin synthetase to obtain alkaloid shown as a formula (C). The method is mild in condition, free of pollution and simple in process route.

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.

A method of selecting a treatment for a subject having cancer is disclosed. The method comprises:(a) determining a level of catalytic activity of at least one DNA repair enzyme in a biological sample of the subject; and(b) selecting an immune checkpoint regulator as a treatment for a subject having a statistically significant different level of catalytic activity of the DNA repair enzyme as compared to the catalytic activity of the DNA repair enzyme in a biological sample of a healthy subject.

The present application relates to a kind of enzyme prediction method and device, and a kind of computer readable storage medium.The prediction method includes the following steps: obtaining the molecular information of target product;According to the molecular information, and the performance expectation of enzyme catalytic reaction to generate the target product, determine the performance descriptor of target enzyme for generating the target product;According to the performance descriptor, mathematical fitting is carried out to determine the matrix descriptor of the target enzyme;According to the matrix descriptor, determine the multiple amino acid residue descriptor involved in the target enzyme;And according to the multiple amino acid residue descriptor, determine the amino acid sequence of the target enzyme.Through executing these steps, the prediction method can efficiently and reliably select catalytic enzyme, to facilitate the efficient production of target product, and reduce the output and discharge of side reaction, to promote the further development of enzyme catalysis technology as a kind of green chemical technology.

The invention relates to the technical field of biological detection, and discloses a tyrosinase activity detection method based on in-situ fluorescence generation and application, and the method comprises the following steps: mixing L-tyrosine with 3-hydroxyphenylboronic acid; adding a biological enzyme sample solution, incubating at a constant temperature, and accumulating L-dopa by enzyme catalysis; then adding an alkaline adjusting solution to construct an alkaline environment, inducing the 3-hydroxyphenylboronic acid and L-dopa to generate a specific boric acid esterification reaction, and generating a fluorescent borate compound in situ; and finally, adding a constant-volume stop solution to maintain an alkaline environment and complement the volume, and detecting the fluorescence intensity. According to the method, a step-by-step pH regulation strategy is adopted, the enzyme activity is guaranteed under the neutral condition, then color development is promoted under the alkaline condition, and the problem that dynamic conditions of the two are incompatible is solved. The method has the advantages of low background interference, high sensitivity, good reproducibility and the like by utilizing specific recognition of a phenylboronic acid group on a catechol structure, and can be applied to food browning analysis, whitening drug screening and disease diagnosis.

The invention discloses a difunctional alcohol dehydrogenase derived from Geobacillus thermodenitrifis, the difunctional alcohol dehydrogenase takes NAD < + > as a cofactor, can specifically catalyze a continuous oxidation reaction of omega-hydroxy fatty acid, and catalyzes the omega-hydroxy fatty acid to synthesize alpha, omega-binary fatty acid through single enzyme catalysis without an aldehyde intermediate. The alcohol dehydrogenase has dual catalytic functions of alcohol oxidation and aldehyde oxidation, the oxidation process from hydroxymethylene to carboxyl can be completed in one step, the reaction steps are simplified, accumulation and separation of intermediate aldehyde are avoided, the conversion efficiency is improved, and the alcohol dehydrogenase is alpha, omega-dibasic fatty acid and is a novel alcohol dehydrogenase. The invention provides a simple and efficient biocatalysis way for biosynthesis of dodecanedioic acid, especially dodecanedioic acid, and has important industrial application value.

The invention discloses a lactoferrin gel carrier, a preparation method thereof and application of the lactoferrin gel carrier in an oral delivery system. The preparation method comprises the following steps: mixing a lactoferrin solution with transglutaminase, and reacting under mild conditions to form a gel network. According to the method, gel which is compact in structure and high in stability is formed through enzyme catalytic crosslinking, the mechanical strength and embedding capacity of the gel are remarkably enhanced, and the method is suitable for embedding multiple active ingredients (such as probiotics, polyphenol and vitamins) sensitive to heat, oxygen or shear force. The obtained gel carrier can effectively isolate oxygen, moisture and adverse processing environments, and the stability of embedded components in processing, storage and transportation is remarkably improved. The carrier can be slowly released in a gastrointestinal tract environment, and active ingredients are prevented from being degraded too early in gastric acid, so that the intestinal absorption rate and the bioavailability of the carrier are improved. The materials used in the invention are natural proteins, are safe and non-toxic, and accord with food and health care product application standards.

The application belongs to the field of bioengineering. The application provides a molecular modification design method for improving the hydrophobicity of the catalytic center of bacillus subtilis protease, which comprises the following steps: searching for a resolved bacillus subtilis protease crystal structure in a protein database PDB, generating an enzyme-substrate complex by docking a hexapeptide substrate through a Glide mode of software, calculating the polar charge of each amino acid residue of polar atoms N and O and H combined thereof within a 10 angstrom range of the catalytic center amino acid of the bacillus subtilis protease by using a PPC force field, calculating the absolute value sum of the polar charge, selecting a potential mutation site of the bacillus subtilis protease, virtually mutating the potential mutation site into a large steric hindrance nonpolar amino acid, calculating the absolute value sum of the polar charge of polar atoms N, O and H within a 10 angstrom range of the catalytic center amino acid of the single-point mutant by using the PPC force field, selecting a virtual bacillus subtilis protease single-point mutant, expressing the mutant and iteratively mutating, re-expressing, obtaining a modified bacillus subtilis protease mutant, and verifying the hydrophobicity. The molecular modification design method can quickly and effectively reduce water molecules in the catalytic center of the bacillus subtilis protease and improve the hydrophobicity thereof. It has been verified that the enzyme modification method is effective and reliable.

The utility model discloses a constant-temperature and constant-pressure control device for biological enzyme catalysis, and relates to the field of medical intermediates. A biological enzyme catalysis constant-temperature and constant-pressure control device comprises a reaction kettle, the upper end of the reaction kettle is communicated with a biological enzyme adding pipe, a substrate adding pipe, a manhole pipe and an exhaust pipe, the bottom of the reaction kettle is communicated with a discharging pipe, and the biological enzyme catalysis constant-temperature and constant-pressure control device further comprises a gas storage box fixedly installed on the reaction kettle; compared with a traditional temperature control mode, the temperature control device not only can quickly and uniformly control the temperature of reactants and bio-enzyme and reduce the temperature difference inside and outside the reactants and the bio-enzyme, but also can monitor and accurately adjust the pressure in the reaction kettle in real time, realize constant-pressure control and ensure that the bio-enzyme catalytic reaction is carried out under a stable pressure condition; the adverse effect on the reaction due to pressure fluctuation is avoided, the reactant and the biological enzyme are mixed more sufficiently due to the disturbance effect of the gas on the reactant, the reaction efficiency is remarkably improved, and the yield and quality of the catalytic reaction of the biological enzyme are improved.

The invention discloses a leucine-containing dipeptide mixture easy to dissolve and reduced in bitterness as well as a preparation method and application of the leucine-containing dipeptide mixture. The mixture comprises the following components in percentage by mass: not less than 90% of alanyl-leucine, 0-5% of free leucine, less than 1% of water and not more than 0.10% of other impurities. The solubility of the mixture at room temperature reaches up to 500 g / L, the mixture is kept transparent and free of precipitates, the bitterness is reduced by 65% or above compared with leucine, the taste can be improved without a taste masking agent, and the mixture is suitable for sports nourishment and functional food. According to the preparation method, an enzyme catalysis reaction is adopted, and the steps of solid-liquid separation, pH adjustment, crystallization, nanofiltration concentration, drying and the like are performed, so that the total yield is not lower than 90%, the purity is not lower than 99.5%, and high solubility, low bitter taste, instant solubility and environmental friendliness are achieved; and the method has a wide industrial application scene.

The invention relates to a preparation method of ultrathin two-dimensional cobalt oxide rich in oxygen vacancies and an application of the ultrathin two-dimensional cobalt oxide rich in oxygen vacancies in food total antioxidant capacity detection, and belongs to the fields of low-dimensional nano materials, biological mimic enzyme catalysis and analytical chemistry. According to the preparation method, cobalt acetylacetonate and hexadecyl trimethyl ammonium bromide are adopted as raw materials, and the ultrathin two-dimensional cobalt oxide nano-enzyme rich in oxygen vacancies is prepared through a hydrothermal reaction and high-temperature pyrolysis. The obtained ultrathin two-dimensional cobalt oxide nano-enzyme rich in oxygen vacancies has excellent peroxidase-like catalytic activity and selectivity. The oxygen-vacancy-rich metal oxide has the advantages of high stability, easy mass production and low preparation cost, and is expected to be widely used in the fields of biosensing, agriculture, food engineering, catalysis and the like.

The invention discloses a nitrilase mutant and an application of the nitrilase mutant in preparation of (S)-3-methylheptanoic acid. The nitrilase mutant disclosed by the invention has high catalytic activity and stereoselectivity, and can overcome the defects of low substrate concentration, low stereoselectivity, high cost, environmental pollution and the like in the existing method, so that 3-methylheptonitrile can be quickly catalyzed to generate (S)-3-methylheptanoic acid under high substrate concentration. In addition, the method also has the effects of good enzyme catalysis effect, high product purity, high recovery rate, simple steps, greenness, environmental protection and the like.

The present invention relates to a biocatalytic synthesis of esters that can also be implemented on an industrial scale. In particular, the invention relates to a process for the production of esters, via a hemiacetal intermediate, consisting of the following steps: – a step of bringing into contact, in a reaction medium, • a mixture of a C1– Cn alcohol and a C1– Cn aldehyde with an enzymatic catalytic system comprising an oxidized cofactor selected from NAD(P)+ and NAD+ and a polypeptide of the oxidoreductase group having preferential dehydrogenase activity toward the formed hemiacetal and the starting aldehyde, or alternatively • a C1– Cn alcohol with an enzymatic catalytic system comprising an oxidized cofactor selected from NAD(P)+ and NAD+ and a polypeptide of the oxidoreductase group having preferential dehydrogenase activity toward the formed hemiacetal, the starting alcohol, and the formed aldehyde, or alternatively • a C1– Cn aldehyde with an enzymatic catalytic system comprising a reduced cofactor selected from NAD(P)H or NADH and a polypeptide of the oxidoreductase group having preferential dehydrogenase activity toward the starting aldehyde and the formed hemiacetal, where n may be any number, and – a step of isolating the corresponding ester.

The utility model relates to the technical field of catalysis equipment, and discloses a device for researching a composite reaction of photocatalysis and enzyme catalysis, which comprises a casing, and a catalysis bin is fixedly mounted in the casing. According to the device for researching the composite reaction of photocatalysis and enzyme catalysis, due to the design of the stirring blades, an all-directional stirring flow field can be generated in the catalysis bin, so that enzyme and a substrate are uniformly distributed in the whole reaction system, the contact probability of the enzyme and the substrate is greatly increased, the catalytic activity of the enzyme is fully exerted, and the catalytic activity of the enzyme is improved. The surrounding type illumination structure is innovatively designed, so that the catalytic lamp tube can irradiate the materials without dead angles, the materials are always kept in a moving state under the stirring of the stirring blades, the materials can receive illumination with consistent intensity, illumination dead angles caused by traditional single-side or limited-angle illumination are thoroughly eliminated, and the illumination efficiency is improved. All parts of the material fully absorb light energy, so that the consistency and the overall efficiency of the photocatalytic reaction are effectively improved.