26 results about "Isoamylase" patented technology

The method for preparing D-mannose through catalysis can effectively reduce the amount of by-products glucose and fructose, and greatly improves the conversion rate of D-mannose. Specifically, engineering bacteria for expressing isoamylase genes and engineering bacteria for expressing alpha-glucan phosphorylase genes, glucophosphate mutase genes, difunctional enzyme glucophosphate isomerase / mannose 6-phosphate isomerase genes and mannose 6-phosphate phosphatase genes are utilized, starch or starch derivatives are used as substrates, and the starch or starch derivatives are used as substrates. A phosphate buffer solution and Mg < 2 + > are added, a preliminary catalysis system is constructed, after the reaction is completed, an incompletely-reacted substrate and maltodisaccharide exist in the reaction system, the incompletely-reacted substrate and maltodisaccharide can be hydrolyzed into glucose by glucoamylase, and the polyphosphoglucokinase can be used for catalyzing the reaction of the polyphosphoglucokinase under the assistance of sodium hexametaphosphate. All glucose is converted into phosphorylated glucose, then D-mannose is generated, and by-products in a system are removed while the yield is increased.

The invention belongs to the technical field of maltose, and particularly relates to a preparation method and application of maltose syrup. The preparation method of the malt syrup comprises the following steps: S1, adding water into corn starch to obtain a mixture, and extruding to obtain a substance I; s2, adding water into the substance I to regulate the mass fraction of the substance I to be 25-35% and the pH value to be 5.5-6.5, adding high-temperature-resistant alpha-amylase and anhydrous calcium chloride, liquefying at 90-100 DEG C for 20-30 minutes, cooling to 65-75 DEG C, adding medium-temperature alpha-amylase, and continuing liquefying for 15-20 minutes to obtain a substance II; s3, feeding the substance II into a saccharifying tank, adjusting the pH value to 5.0-5.5 and the temperature to 50-60 DEG C, adding modified beta-amylase, isoamylase and sodium thiosulfate, saccharifying for 3-6 hours, heating to 55-65 DEG C, adding pullulanase, and saccharifying for 5-10 hours to obtain a substance III; and S4, carrying out enzyme deactivation treatment on the substance III, carrying out secondary filtration and decoloration, carrying out ion exchange, collecting an ion exchange liquid, and carrying out vacuum concentration. The preparation method of the malt syrup is simple to operate, and the prepared malt syrup is high in maltose content and good in stability.

The invention relates to the technical field of bioengineering (IPC classification number: C12N), in particular to a bifunctional starch debranching enzyme, a gene thereof, a recombinant engineering bacterium containing the gene and application of the bifunctional starch debranching enzyme. The DNA sequence of the gene is as shown in SEQ ID NO: 1. The amino acid sequence of the difunctional starch debranching enzyme is as shown in SEQ ID NO: 2. The invention provides a novel difunctional starch debranching enzyme gene, the full length of the gene is 2139bp, and 712 amino acids are encoded; the starch debranching enzyme has the characteristics of better high temperature resistance and high activity under a slightly acidic pH (Potential of Hydrogen) condition. The specific activity of the bifunctional isoamylase provided by the invention is 1.7 times that of isoamylase (PromozymeD2), and the bifunctional isoamylase can be well applied to the technical fields of grain processing, food industry, brewing, fermentation, textile industry, medicine and the like.

The invention belongs to the technical field of enzyme engineering and gene engineering, and particularly relates to a recombinant immobilized enzyme, an expression gene thereof and application of the recombinant immobilized enzyme in production of macrocyclodextrin. According to the preparation method, SpyTag and SpyCatcher peptides are fused to the N end of isoamylase and the N end of 4-alpha-glucanotransferase respectively, the 4-alpha-glucanotransferase modified by the SpyTag and the isoamylase modified by the SpyCatcher are obtained, and after spontaneous isopeptide bonds are formed between the SpyTag and the SpyCatcher, the self-assembled macrocyclodextrin production enzyme cluster is obtained. The obtained macrocyclodextrin production enzyme cluster forms an enzyme aggregate with a three-dimensional structure under the traditional glutaraldehyde-mediated catalytic action, namely the recombinant immobilized enzyme. The recombinant immobilized enzyme disclosed by the invention can be repeatedly utilized, is simple and convenient to operate, is easy to separate a converted product, and can be applied to industrial production of the macrocyclodextrin.

The invention discloses a preparation method of Lipu taro powder and application of the Lipu taro powder in low-GI meal replacement food, and belongs to the technical field of taro processing. The preparation method comprises the following steps: (1) mixing and pulping tea polyphenol, ascorbic acid and fresh Lipu taro to obtain Lipu taro pulp; (2) performing enzymolysis on the Lipu taro pulp by using isoamylase, adding stem and leaf juice of Lipu taro into the enzymolysis pulp, and mixing to obtain pretreated Lipu taro pulp; (3) inoculating the pretreated Lipu taro pulp with a lactobacillus plantarum strain LAPB04, and performing fermentation treatment to obtain fermented Lipu taro pulp; and (4) performing spray drying on the fermented Lipu taro slurry to obtain the Lipu taro powder. The GI value of the Lipu taro powder can be reduced by increasing the content of SDS and RS in the Lipu taro powder, blood glucose fluctuation can be controlled after intake, and the Lipu taro powder is low in preparation cost, low in nutrition loss, suitable for being eaten by a large number of consumers and particularly suitable for being eaten by people with special chronic diseases and with sugar and fat control requirements.

The invention provides a preparation method of a longan pulp extract as well as a product and application of the longan pulp extract, the preparation method comprises the following steps: mixing a longan pulp raw material with a compound enzyme, performing enzymolysis, performing enzyme deactivation and filtration on enzymatic hydrolysate after enzymolysis, and collecting filtrate to obtain the longan pulp extract, the compound enzyme comprises a combination of pectate lyase, isoamylase, xylanase, neutral protease and hemicellulase. According to the method, effective components in the longan pulp are extracted by adopting a specific compound enzyme, related components in the longan pulp can be efficiently extracted, a potential synergistic relationship exists among pectate lyase, isoamylase and xylanase, and the extraction effect can be remarkably improved after the pectate lyase, the isoamylase and the xylanase are combined for use; the prepared extract product has the effects of moisturizing, fading wrinkles, tightening, resisting oxidation and brightening skin.

The method for catalytically preparing D-mannose provided in the application can effectively reduce the amount of by-products glucose and fructose, and greatly improve the conversion rate of D-mannose. Specifically, the engineering bacteria expressing isoamylase gene and the engineering bacteria expressing alpha-glucan phosphorylase gene, glucose phosphomutase gene, bifunctional enzyme glucose phosphate isomerase / mannose 6-phosphate isomerase gene and mannose 6-phosphate phosphatase gene are used, starch or starch derivatives are used as substrates, phosphate buffer solution and Mg 2+ A preliminary catalytic system is constructed, and after the reaction is completed, there are unreacted substrates and maltodextrin in the reaction system, the saccharifying enzyme can hydrolyze the unreacted substrates and maltodextrin into glucose, the polyphosphate glucose kinase can convert all the glucose into phosphorylated glucose with the assistance of sodium hexametaphosphate, and then D-mannose is generated, thereby improving the yield and removing the by-products in the system.

The invention provides a preparation method of RS3 type resistant starch, which comprises the following steps: (1) mixing starch, compound enzyme and deionized water to prepare a starch aqueous solution; sequentially carrying out autoclaving treatment and cooling to obtain starch paste; the compound enzyme comprises a combination of at least two of alpha-amylase, beta-amylase or glucamylase; (2) mixing the starch paste, deionized water, pullulanase and isoamylase, and debranching under the condition that the pH value is 4-6; and (3) after crystallization, carrying out solid-liquid separation, and collecting solids to obtain the RS3 type resistant starch. The RS3 type resistant starch is prepared through a hot-pressing method and an enzymolysis method, and gelatinization and liquefaction reactions are carried out at the same time, so that the reaction efficiency is remarkably improved, and the reaction steps are simplified; the pullulanase and the isoamylase have a synergistic effect, and the alpha-amylase, the beta-amylase and the glucamylase have a synergistic effect, so that the formation of the resistant starch is synergistically promoted.

The invention discloses a preparation method of Lipu taro meatballs with a low glycemic index, and belongs to the technical field of taro processing. The preparation method comprises the following steps: quickly freezing fresh Lipu taros, and crushing to obtain Lipu taros powder; separating mucus and starch of the Lipu taro powder by taking rice wine as a solvent and adopting a subcritical fluid extraction method; carrying out enzymolysis treatment on the Lipu taro starch primary product by using pullulanase and isoamylase to obtain enzymolysis slurry; preparing meat balls by using minced streaky pork, the enzymolysis slurry, Lipu taro mucus, cassava starch, curdlan, composite phosphate, table salt, white pepper powder, egg white, minced scallions, fresh ginger and chicken essence as raw materials, and curing to obtain the Lipu taro meat ball finished product with the low glycemic index. The Lipu taro meat ball with the low glycemic index is a low-GI food, is suitable for being eaten by vast consumers, is particularly suitable for being eaten by people with sugar and fat control requirements, and has the characteristics of high yield, low cooking loss rate, high water retention rate, good texture property and the like.

A method for preparing modified starch by using a transglutaminase in conjunction with a double-enzyme method, comprising the following steps: pretreatment; directed enzymatic hydrolysis: adding pullulanase into a gelatinized starch emulsion for primary directed enzymatic hydrolysis, and adding isoamylase into a primary enzymatic hydrolysis solution for secondary directed enzymatic hydrolysis; and molecular orientation induction: adding a transglutaminase into the starch emulsion that has undergone the directed enzymatic hydrolysis, so as to carry out molecular orientation induction, carrying out enzyme inactivation after the enzymatic hydrolysis is completed, and carrying out centrifugal drying, thereby obtaining modified starch.

The present disclosure features compositions and methods for the treatment of actinomycetia (e.g., corynebacteriales) infections, e.g., caused by mycobacterial cells. In one aspect, the disclosure features a composition containing unencapsulated proteins that include one or more of (a) a Lysin A; (b) a Lysin B; (c) an isoamylase; and (d) an α-amylase. The composition optionally further includes a supramolecular structure including one or more (a) a Lysin A; (b) a Lysin B; (c) an isoamylase; and (d) an α-amylase. In another aspect, the invention features a method of treating a bacterial infection in a subject by administering a composition of unencapsulated lytic proteins as described herein to the subject in an amount and for a duration sufficient to treat the bacterial infection, optionally in combination with encapsulated lytic proteins. The encapsulated lytic proteins and the unencapsulated lytic proteins can be in the same or different composition and can be administered simultaneously or sequentially.

This invention discloses a multi-step sequential enzymatic hydrolysis combined with multi-stage membrane purification method for preparing kudzu oligosaccharides, relating to the field of functional food processing technology. The preparation method includes the following steps: adding kudzu powder to water to prepare a starch slurry, then liquefying it using α-amylase, followed by enzymatic hydrolysis using debranching enzymes and glycoside hydrolases to obtain an enzymatic hydrolysate; performing membrane separation on the enzymatic hydrolysate to obtain a fraction with a molecular weight higher than 1 kDa and lower than 5 kDa, followed by drying to obtain the kudzu oligosaccharides; the debranching enzymes are pullulanase and isoamylase; the glycoside hydrolases are β-glucosidase or α-transglucosidase. This preparation method can effectively increase the proportion of the DP3-15 fraction of kudzu oligosaccharides, achieving a product purity of over 91% and a total yield exceeding 22%.

The present disclosure relates to compositions and methods for the treatment of actinomycete (e.g., Corynebacteriales) infections caused by, for example, mycobacterial cells. In one aspect, the present disclosure relates to a composition containing an unencapsulated protein comprising one or more of (a) lysin A; (b) lysin B; (c) isoamylase; and (d) α-amylase. The composition may further comprise a supramolecular structure comprising one or more of (a) lysin A; (b) lysin B; (c) isoamylase; and (d) α-amylase. In another aspect, the present invention is a method for treating a bacterial infection in a subject, the method comprising administering to the subject a composition of the unencapsulated lytic protein described herein, optionally in combination with an encapsulated lytic protein, in an amount and for a time sufficient to treat the bacterial infection. The encapsulated lytic protein and the unencapsulated lytic protein can be the same or different compositions and can be administered simultaneously or sequentially.

The invention relates to the field of starch type textile impregnating compounds, and discloses a film-forming agent as well as a preparation method and application thereof. The method comprises the following steps: performing acidolysis and gelatinization on starch slurry to obtain starch paste, mixing the starch paste with pullulanase and isoamylase, and performing enzymolysis. By adopting the method provided by the invention, the film-forming agent suitable for application can be prepared by utilizing the common starch which is easy to obtain, and the produced product is relatively stable in performance, is more friendly to downstream application and has a higher practical production value.

The invention discloses a tagatose-6-phosphate phosphatase mutant and application of the tagatose-6-phosphate phosphatase mutant in production of D-tagatose, and belongs to the technical field of enzyme engineering. The tagatose-6-phosphate phosphatase mutant disclosed by the invention is obtained by mutating wild type tagatose-6-phosphate phosphatase of which the amino acid sequence is shown as SEQ ID NO.5, and the mutation site is selected from at least one of the 45th site, the 108th site, the 168th site and the 186th site. After the mutant is coupled with isoamylase, dextran phosphorylase, glucose phosphate mutase, glucose-6-phosphate isomerase, 4-alpha-glucosyltransferase and tagatose-6-phosphate isomerase, the yield of D-tagatose synthesized by substrate starch is increased, the accumulation amount of by-products glucose and fructose is low, and the yield of D-tagatose synthesized by substrate starch is increased. Therefore, the production efficiency is greatly improved, and the separation and purification cost is reduced. Therefore, the mutant disclosed by the invention is suitable for industrial production and has a good application prospect.

The present invention discloses an isoamylase, its gene, an engineered bacterium containing the gene and its application; the present invention provides an isoamylase gene, the nucleotide sequence of which is shown in SEQ ID NO.1. The full length of this gene is 2130 bp, the G+C content is 69.11%, encoding 709 amino acids, and the amino acid sequence is shown in SEQ ID NO.2. The isoamylase provided by the present invention has an adaptability to a wide pH range. When reacting at pH 6.0 - 8.0, it has relatively high enzyme activity, and when reacting at 40 °C and pH 7.0, the enzyme activity is the highest. The isoamylase provided by the present invention has a hydrolyzing effect on both α-1,4 and α-1,6 glycosidic bonds. The specific activity of hydrolyzing corn starch is 250.46 U / mg. When used in combination with maltogenic amylase BMAL, it can improve the utilization efficiency of maltogenic amylase BMAL for branched-chain substrates.

The application discloses a method for constructing an in-vitro multi-enzyme molecular machine to prepare laminaribiose through multi-enzyme cascade catalysis, and belongs to the field of enzyme catalytic preparation of laminaribiose. The method for preparing laminaribiose disclosed by the application comprises converting glucose units in starch into glucose-1-phosphate and glucose through starch phosphorylase and glucosidase respectively, and then synthesizing laminaribiose from glucose-1-phosphate and glucose through laminaribiose phosphorylase. In the process, the utilization rate of starch and the final concentration of laminaribiose can be further improved by adding other auxiliary enzymes, such as isoamylase, to promote complete phosphorolysis of starch. The technical method has the advantages of cheap and easy-to-obtain substrate, low production cost, high product yield, simple separation and purification, and the like, and can realize the large-scale production of laminaribiose.

The invention relates to the technical field of bioengineering, in particular to a method for preparing trehalose through enzyme catalysis, which comprises the following steps: (1) enzyme pretreatment: taking maltodextrin with specific composition as a substrate, and carrying out segmented temperature control pretreatment by adopting medium-temperature alpha-amylase, isoamylase and pullulanase; (2) enzyme catalytic conversion: carrying out catalytic reaction on the pretreatment liquid, MTSase and MTHase in the presence of a compound stabilizer; and (3) purifying the product to obtain a high-purity trehalose product. According to the method, enzyme pretreatment is carried out before enzyme catalytic conversion, so that the conversion rate of the trehalose can reach about 85%, the reaction time is shortened to 20 hours, and the method has remarkable industrial application value.

The present disclosure features compositions and methods for the treatment of actinomycete (e.g., Corynebacterium) infections, e.g., caused by Mycobacterium cells. In one aspect, the present disclosure features a composition comprising an unencapsulated protein comprising one or more of: (a) lysin A; (b) lysin B; (c) an isoamylase; and (d) an alpha-amylase. The composition optionally further comprises a supramolecular structure comprising one or more of the following: (a) lysin A; (b) lysin B; (c) an isoamylase; and (d) an alpha-amylase. In another aspect, the invention features a method of treating a bacterial infection in a subject by administering to the subject a composition of an unencapsulated cleavage protein as described herein, optionally in combination with an encapsulated cleavage protein, in an amount and duration sufficient to treat the bacterial infection. The encapsulated cleavage proteins and the unencapsulated cleavage proteins can be in the same or different compositions, and can be administered simultaneously or sequentially.

The invention provides low-GI steamed buns and a preparation method thereof. Saccharomyces cerevisiae, lactobacillus brevis, lactobacillus plantarum and lactobacillus pentosus which are separated and screened from traditional yeast are used for performing multi-strain fermentation on dough, a composite modifier composed of polydextrose, isoamylase and tannic acid is added after fermentation, and steaming is performed after fermentation to obtain the low-GI steamed buns. The prepared steamed bun has low GI value and excellent sensory quality, the bottleneck problem that low GI, texture characteristics and sensory quality are difficult to consider in the traditional process is solved, the unification of low GI health function and excellent eating quality is realized, the process is simple, the trend of cleaning labels is met, and industrial production is easy.

The invention discloses isoamylase and a gene thereof, an engineering bacterium containing the gene and application of the engineering bacterium. The invention provides an isoamylase gene, the nucleotide sequence of which is as shown in SEQ ID NO.1, the full length of the gene is 2130 bp, the G + C content is 69.11%, 709 amino acids are encoded, and the amino acid sequence is as shown in SEQ ID NO.2; the isoamylase provided by the invention has wide pH range adaptability, has higher enzyme activity when the reaction is carried out at the pH of 6.0-8.0, and has the highest enzyme activity when the reaction is carried out under the conditions that the temperature is 40 DEG C and the pH is 7.0; the isoamylase provided by the invention has a hydrolysis effect on alpha-1, 4 and alpha-1, 6 glucosidic bonds, the specific activity of hydrolyzed corn starch is 250.46 U / mg, and when the isoamylase is combined with maltogenic amylase BMAL for use, the utilization efficiency of the maltogenic amylase BMAL on a branched chain substrate can be improved.

The invention provides a recombinant plasmid, a heat-resistant isoamylase gene engineering strain and application, the nucleotide sequence of a promoter in the recombinant plasmid is shown as SEQ ID NO.1 in a sequence table, and the nucleotide sequence of RBS is shown as SEQ ID NO.2 in the sequence table. The gene engineering strain is prepared by taking bacillus subtilis as a host. The strain is obtained by transferring plasmids with the fragment into bacillus subtilis and screening to obtain correct transformants, can be used for producing soluble isoamylase, can efficiently express isoamylase in cells, is short in fermentation period and low in production cost, does not form inclusion bodies, is easy to purify, and is beneficial to large-scale production of isoamylase.

The invention belongs to the field of biological enzyme preparations, and particularly relates to a compound enzyme preparation for improving combustibility of Nanping cigars and application of the compound enzyme preparation. According to the method, the Nanping cigar tobacco leaves with improved combustion performance are prepared by harvesting the Nanping cigars, airing the Nanping cigars, screening and compounding enzyme preparations, optimizing an enzymolysis mode and controlling enzymolysis parameters only by adopting a compound enzyme preparation without non-enzyme preparations. Pectate lyase and pectin esterase in pectinase, papain in protease, beta-amylase saccharifying enzyme and isoamylase in amylase and cellulase are screened out and combined, and further optimized that pectate lyase, pectate esterase and cellulase are subjected to mixed enzymolysis, enzymolysis is carried out, enzymolysis is carried out, and enzymolysis is carried out. The papain, beta-amylase and isoamylase solutions are mixed for enzymolysis, and the temperature and time of two times of enzymolysis are controlled, so that the combustibility of the Nanping cigar tobacco leaves is remarkably improved, and meanwhile, the smoking evaluation result of the Nanping cigar tobacco leaves is good.

The application discloses a kind of mannose-producing multi-enzyme co-expression genetically engineered bacteria and its construction method and application.Belongs to the field of bioengineering technology.The genetically engineered bacteria co-expresses isoamylase, alpha-dextran phosphorylase, glucose phosphoketolase, bifunctional enzyme glucose phosphoisomerase / mannose 6-phosphate isomerase and 6-phosphomannose phosphatase.The genetically engineered bacteria can effectively convert maltodextrin into mannose.The method of the application can be used for whole-cell production compared with existing mannose production methods, has the advantages of high safety, high yield, simple production process, low cost and easy to scale up, etc.

The invention relates to a preparation method of hydrogenated starch hydrolysate, which comprises the following steps: (1) mixing plant starch with water to obtain gelatinized plant starch; (2) mixing the gelatinized plant starch with a compound enzyme, carrying out an enzymolysis reaction, and carrying out deactivation treatment on the enzyme after the reaction to obtain a polysaccharide slurry; (3) decolorizing the polysaccharide slurry obtained in the step (2); (4) carrying out hydrotreatment on the decolorized polysaccharide slurry to obtain a crude hydrogenated starch hydrolysate; (5) filtering and concentrating the crude hydrogenated starch hydrolysate obtained in the step (4) to obtain hydrogenated starch hydrolysate; wherein the compound enzyme in the step (2) comprises gamma-amylase, isoamylase, glycogen phosphorylase and alpha-amylase. According to the preparation method, gelatinized plant starch is comprehensively and efficiently hydrolyzed, and the starch is decomposed into products with proper sizes and structures, so that the prepared hydrogenated starch hydrolysate has excellent stability and moisturizing performance.

The invention belongs to the technical field of food and food additive production, and provides a method for preparing high amylose and acetylated high amylose through synergy of isoamylase and heat-moisture treatment, the acetylated high amylose is an acetylated derivative of high amylose and is obtained by taking high amylose as a raw material; the method comprises the following steps: firstly, mixing corn starch with a debranching enzyme solution, carrying out moisture balance, carrying out heat-moisture treatment at 80 DEG C for 16 hours, and carrying out enzyme deactivation and drying to obtain high-amylose starch; then preparing acetylated high-amylose starch through the steps of sodium sulfate solution dispersion, sodium hydroxide activation, vinyl acetate acetylation and the like; according to the method disclosed by the invention, the problems of high energy consumption and low amylose content of a traditional process are solved through an enzymic method-physical synergistic modification technology, the content of the prepared high amylose can reach 80.8%, and the process is simple and pollution-free; the obtained product can be used as resistant starch to be applied to functional food base materials and biochemical drug carriers.