11 results about "Isoamylase" patented technology

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 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.

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 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 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 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 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 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.