253 results about "Beta-Galactosidases" patented technology

An isolation plating medium for the identification of Salmonella bacteria in a sample containing a plurality of different bacteria comprising a mixture of a carbohydrate capable of being a metabolic source for Salmonella bacteria and supporting colonies of Salmonella bacteria, a pH indicator dye that changes the color of the plating medium to a first color different from the color of the medium responsive to a change in the pH of the medium, a first substrate that does not react with Salmonella bacteria and injects color into the medium of a second color responsive to the presence of beta-galactosidase, the second color contrasting with the first color and the color of the medium, a second substrate that does not react with Salmonella bacteria and injects color into the medium of substantially the same color as the second color responsive to the presence of beta=galactosidase, and an ingredient for thickening the mixture in sufficient quantity to solidify the mixture.

The invention discloses a DNA fragment with a promoter function and an application. The DNA fragment is any one of the following sequences: (a) a nucleotide sequence shown in SEQ ID NO: 1 or a complementary sequence of the nucleotide sequence; (b) a nucleotide sequence having a promoter function identical to SEQ ID NO: 1 or a complementary sequence of the nucleotide sequence obtained by substituting, deleting or adding one or more nucleotides on the nucleotide sequence shown in the SEQ ID NO: 1; and (c) sequences of one or more ribosome bind sites added in the nucleotide sequence shown in the SEQ ID NO: 1. The DNA has a promoter function and is high in expression activity, and high expression of exogenous genes can be realized under a condition that inducers are not needed, and the DNA fragment is applied to expression of heatproof beta-galactosidase and transglutaminase. An effective tool is particularly provided for expression of bacillus amyloliquefaciens.

The invention relates to construction of a heat-resistant beta-galactosidase mutant. When the heat-resistant beta-galactosidase (BgaB) mutant (BgaB-F341T) provided by the invention is used for a lactose hydrolysis process to produce low-lactose products, the inhibition action of the hydrolysis products to the hydrolytic activity of the enzyme can be effectively removed, so that the hydrolysis reaction is thoroughly carried out and the hydrolysis efficiency is improved; and when the heat-resistant beta-galactosidase (BgaB) mutant (BgaB-F341T) is used to replace medium-temperature lactase, the low-temperature hydrolysis process of low-lactose milk can be innovated. The hydrolysis temperature can be set at 55-60 DEG C, at the temperature, not only is the hydrolysis reaction speed high, but also common impure bacteria in the milk has stopped growing, therefore the product hygiene and quality problems caused by impure bacterial contamination can be effectively controlled; and in addition, by the high-temperature hydrolysis process using the heat-resistant lactase, the lactose hydrolysis and pasteurization processes can be combined, not only is the production cycle shortened, but also the energy consumption is reduced by taking full use of the waste heat from the pasteurization process, thus significantly saving production cost.

Methods and compositions are provided for detecting molecular translocations, particularly protein translocations within and between subcellular copartments, using at least two components that exhibit a localization-dependent difference in complementation activity. In particular, alpha-complementing β-galactosidase fragments are provided. These β-galactosidase reporter fragments display significantly enhanced enzymatic activity when one fragment is localized in a membrane. Methods for carrying out no-wash ELISA assays based on the reporter component system are also provided.

The invention discloses a high efficiency turning glycosyl beta-galactosidase gene. The genes are gained by enterobacter cloacae B5 CGMCC No.1401 gene set DNA under PCR amplification. The whole length of gene nucleotide sequence is 3090 basic groups, and coding 1029 amino acid. The recombinase features are that enzyme is quart-subunit albumen; polymer molecular weight are 391kD; mono subunit are 97.8kD; the enzyme to lactose Km value is 0.32mmol/L, Vmax is 210.70umol/(L.min); and it to onitrophenol-beta-D-galactoside Km value is close to 0; its optimum reaction temperature is 35 centigrade degree; the pH value is from 6.5-9.5; it can be stored at least two months at room temperature; oligomerization galactose yield is 55%; receptor substrate specificity of the enzyme turning glycosyl is very wild; it can used to compose multi galactoside compounds. The gained enzyme gene can be used to modify gene to gain new beta-galactoside synthetase, and improve its combined efficiency fundamentally.

The invention relates to beta-galactosidase and application thereof, in particular to a beta-galactosidase with a cellulose adsorption zone and application thereof in the production of galactooligosaccharide, and belongs to the technical field of enzyme protein engineering. The beta-galactosidase gene with the cellulose adsorption zone has a nucleotide sequence shown as SEQ ID No.1; and the beta-galactosidase coded by the gene has an amino acid sequence shown as SEQ ID No.2. The related GOS production method has the advantages of low cost, high yield, simple and reasonable steps, and the like, and has great industrialized application prospect.

The invention discloses a coding beta-galactosidase gene and an expression and an application thereof. The invention sieves and clones a beta-galactosidase gene (SEQ ID NO:1) coming from Cellulononas sp. from Sinkiang soil. The DNA overall length of the beta-galactosidase gene group is 2076bp, and (G+C) percent content is 72.9% and the beta-galactosidase gene group is deduced to encode 629 amino acid. The beta-galactosidase encoded by genes has the highest similarity with the beta-galactosidase from Arthrobacter sp., and the similarity is 59%. Enzymology property measurements indicate that the beta-galactosidase of the invention is neutral normal-temperature enzyme. Most of the beta-galactosidase of other Arthrobacter sp. reported by documents belongs to low-temperature psychrophilic enzyme which is obvious different from the beta-galactosidase of the invention in terms of enzymology properties.

The present invention relates to a method of using recombinant Saccharomyces cerevisiae to produce galactooligosaccharides, specifically to a recombinant Saccharomyces cerevisiae with surface display of beta-galactosidase and method for making same and a method of recycling the recombinant Saccharomyces cerevisiae fermentation lactose to produce galactooligosaccharides. The method includes: first of all, building a beta-galactosidase yeast surface display vector, displaying the beta-galactosidase on cell surface of the Saccharomyces cerevisiae, and then recycling the recombinant yeast fermentation lactose to produce galactooligosaccharides. The inventive recombinant Saccharomyces cerevisiae of the surface display beta-galactosidase can be recycled to produce galactooligosaccharides, and has high yields, low production cost, simple process and broad industrialization application prospects.

The invention provides sialic acid-added milk powder with an easy digestion function for premature infants and a preparation method thereof, and relates to the technical field of foods. The milk powder is prepared from the following raw materials: skim milk powder, lecithin, maltodextrin, immune globulin, refined palm olein, vitamin complex, prebiotics, minerals, alpha-whey protein, lactotransferrin, ferrous gluconate, bifidobacterium, sialic acid, edible vegetable oil mixture, beta-galactosidase, tryptophan, threonine and cystine. Compositions of the formula of the milk powder for premature infants is closer to breast milk, memory and intelligence level of premature infants can be improved by the sialic acid ingredient added into the milk powder, and nutrition essential to premature infant growth can be provided by optimizing the proportion of ingredients. The milk powder can be easily digested and absorbed, and can be used for improving the resistance of premature infants and reducing the phenomena of internal heat and iron-deficiency anemia caused by dyspepsia.

The invention discloses a method for producing high-purity oligomate. The high-purity oligomate is prepared by separating from a liquid of enzymatical reaction of the oligomate by synthesizing a special resin and using a simulated mobile bed chromatographic technique. The method comprises the specific steps of: 1), producing a mixture containing glucose, galactose, lactose and the oligomate in the presence of beta galactosidase by taking the lactose as a raw material; and 2), by using a simulated mobile bed chromatographic system, separating the oligomate from other ingredients completely by taking water as an eluent at the operating temperature of between 55 and 75 DEG C to obtain the oligomate-containing components and other miscellaneous components.

The invention discloses a method for testing content of galactooligosaccharide, and in particular relates to a method for testing content of galactooligosaccharide in formula milk powder by means of gas chromatography-mass spectrum. The method comprises the following steps: extracting galactooligosaccharide and lactose from samples to be detected by using hot phosphate buffer liquid; hydrolyzing and centrifuging galactooligosaccharide in extracting liquid by using beta-galactosidase to obtain liquid supernatant; enabling the liquid supernatant to pass through a microfiltration membrane; carrying out nitrogen blowing or performing low-temperature vacuum drying; deriving by using BSTFA and making up to the volume by using acetone. The content of dissociative galactose and lactose in extracting raw liquid and the total quantity of galactooligosaccharide obtained by enzymolysis on decomposition liquid and galactose released by lactose are tested by utilizing a gas phase-mass spectrum combined method, and the content of the galactooligosaccharide in samples is calculated by using the content of galactose content obtained by performing enzymolysis on decomposition liquid to substract the content of galactose obtained by extracting the raw liquid and the content of galactose produced by lactase enzymolysis. The content of galactooligosaccharide in the milk powder is detected by using the method, and the method has the advantages of extremely-low detection and high sensitivity.

The invention relates to a production method of high-content galactooligosaccharide, which comprises the following steps: (1) adding beta-galactosidase into a lactose solution, carrying out enzyme reaction, and heating to terminate the reaction, thereby obtaining a primary enzyme reaction solution; (2) concentrating the primary enzyme reaction solution, adding beta-galactosidase, and carrying out enzyme reaction to obtain a raw sugar solution; and (3) adding activated carbon into the raw sugar solution, heating to inactivate the enzyme, carrying out ion exchange, and concentrating to obtain the galactooligosaccharide. The two enzyme reactions are utilized for the first time, so that the galactooligosaccharide content in the final product reaches 57% or above, thereby solving the problems of high galactooligosaccharide production cost and low productivity in the prior art.

The invention discloses a signal peptide capable of effectively improving protein secretion efficiency and an application of the signal peptide. The amino acid sequence of the signal peptide is shownin SEQ ID NO.1. The nucleotide sequence for encoding the signal peptide is selected from any of the following sequences: (a) a nucleotide sequence shown in SEQ ID NO.2 or a complementary sequence of the nucleotide sequence; and (b) a nucleotide sequence which is obtained through substitution, deletion or addition of one or more nucleotides of the nucleotide sequence shown in SEQ ID NO.2, has a same function of being used a signal peptide with the nucleotide sequence shown in SEQ ID NO.2, or a complementary sequence of the obtained nucleotide sequence. According to the invention, an expressionvector with the combination of the signal peptide and beta-galactosidase encoding gene/transglutaminase zymogen encoding gene is constructed from a vacillus subtilis homologous protein signal peptidelibrary, the signal peptide capable of increasing the secretion of beta-galactosidase can be screened out, and the secretion expression of the transglutaminase zymogen is realized.

A solid plating medium for the presumptive detection of Escherichia coli 0157:H7 which comprises (1) an ingredient which promotes growth of Escherichia coli cells under incubation, (2) an ingredient which inhibits growth of gram positive microorganisms under incubation, (3) an ingredient that inhibits growth of Proteus sp. under incubation, (4) an ingredient which inhibits the growth of strains of Escherichia coli other than Escherichia coli 0157:H7 under incubation, (5) a carbohydrate medium that under incubation is not fermented by Escherichia coli 0157:H7 but which is fermented by other microorganisms including other strains of Escherichia coli, (6) a pH indicator dye which changes the plating media to a first color when the pH of the medium changes, (7) a chromogenic beta-galactosidase substrate that produces precipitate of a second color responsive to beta-galactosidase, the first color contrasting with the second color and the first and second colors blending to produce a third color which contrasts with the first and second colors, and (8) a mass of agar sufficient to solidify the mixture. Also, the method of detecting the presence of Escherichia coli 0157:H7 comprising inoculating the solid plating medium set forth above with a test sample containing Escherichia coli including Escherichia coli 0157:H7, then incubating said plating medium for a period sufficient to obtain colonies of microorganisms and generating one or more of the colors produced by the plating medium, and then examining the surface of the medium for the presence of colonies of the second color.

The invention discloses beta-galactosidase and application thereof. The application method comprises the following steps: cloning beta-galactosidase genes bgl from bacillus coagulans into an expression vector pETDuet-1, transforming the beta-galactosidase genes into Escherichia coli BL21 (DE3), thus obtaining the beta-galactosidase with the expression quantity of 2031U/mg. The expressed beta-galactosidase has the optimal pH value of 6.0 and the optimal temperature of 60 DEG C. The recombinant beta-galactosidase can be used for lactose hydrolysis.

The present invention is low temperature brevibacillus for producing beta-galactosidase and the production process of beta-galactosidase with the brevibacillus strain. By means of preservation, rejuvenation and breeding of the brevibacillus strain (CGMCC. No.1424) and optimized fermentation process, the present invention has short fermentation period and stable fermentation process to obtain beta-galactosidase with excellent high temperature activity and high enzyme activity. The product may be used widely in fermented milk product, beverage, food, medicine and other fields.

The combined vaccine consists of a kind of polypeptide vaccine and one DNA vaccine, and may be used to immunize suscaptible animal in several modes to prevent foot-mouth disease virus infection. The chemically synthetic encoding foot-mouth disease virus VP1 protein has the DNA sequence of antigen amino acid peptide segment and is connected into multicopy serial structure. The antigen gene with serial structure is then connected to beta-galactosidase gene to form fusion gene. When the fusion gene is inserted into protokaryon expression vector, the expressed fusion protein may be compounded into the polypeptide vaccine. When the fusion gene is inserted into eukaryon expression vector, the recombinant eukaryon expression plasmid may be amplified to obtain NDA vaccine.

The invention discloses a DNA fragment of bacillus subtilis with a promoter function and application thereof. The DNA fragment is any one of a, the nucleotide sequence as shown in SEQ ID NO.1 or a complementary sequence thereof; b, a nucleotide sequence obtained by substituting, deleting or adding one or more nucleotides of the nucleotide sequence as shown in SEQ ID NO.1 and having the promoter function the same as that of the nucleotide sequence as shown in SEQ ID NO.1, or a complementary sequence thereof; and c, a sequence obtained by adding one or more ribosome bind sites to the nucleotide sequence as shown in SEQ ID NO.1. The DNA fragment has the promoter function, and also has high expression activity. High expression of exogenous genes can be achieved without adding an inductor. The DNA fragment can be applied to expression of thermostable beta-galactosidase and transglutaminase, and particularly, an effective element is provided for a bacillus subtilis expression-secretion system.

The invention relates to a deep sea derived strain as well as an encoded beta-galactosidase gene and application thereof and belongs to the technical field of biologics. The strain is an Altermononassp. strain ML117, which is preserved in the China General Microbiological Culture Collection Center in December 14, 2017, and the preservation number is CCTCC NO: M2017788. The strain comprises a genefor encoding low-temperature beta-galactosidase, and the low-temperature beta-galactosidase has wide application prospects in low lactose milk production.

The invention discloses a preparation method of galactooligosaccharides, which comprises the following steps: uniformly mixing thalli producing beta-galactosidase with sodium alginate solution to get mixed bacterial liquid; spraying and pressing the mixed bacterial liquid into calcium chloride solution, and soaking to get an immobilized matter; cutting up the immobilized matter, pouring into mixed solution of calcium chloride and chitosan, stirring and soaking; placing particles of the immobilized matter in glutaraldehyde solution for cross-linking, and cleaning to get the particles fixed with cells; and mixing the particles fixed with the cells with lactose solution, filtering after completing stirring reaction, and purifying syrup obtained by filtering so as to get the galactooligosaccharides. By adopting the method, the difficult problems of separation of the thalli, clarification of the syrup and the like in the way of directly using the thalli for performing transformation reaction can be effectively solved, and the production efficiency is improved; the production time is shortened, the production equipment is simplified, and the production cost is saved; and the consumptionof resources is reduced, the immobilized cells containing the beta-galactosidase can be utilized repeatedly, the frequency of fermentation and input into a tank can be reduced, and the pressure on environment friendliness can be reduced.

The invention discloses beta-galactosidase galRBM20_1 and a preparation method and application thereof. The amino acid sequence of the beta-galactosidase galRBM20_1 is as shown in SEQ ID NO.1. Variousenzyme genes are obtained from excrement and urine microorganisms of Yunnan snub-nosed monkeys, and a metagenome Fosmid library of the excrement and urine microorganisms of the Yunnan snub-nosed monkeys is constructed. The beta-galactosidase gene galRBM20_1 is obtained through cloning from the metagenome of the excrement and urine microorganisms of the Yunnan snub-nosed monkeys, and after heterologous expression of escherichia coli, enzymatic property and salt tolerance are researched. The recombinase has higher pH stability and heat stability, and besides, also has favorable salt tolerance.A new source is provided for obtaining the beta-galactosidase gene galRBM20_1, and through efficient recombinant expression, a large number of beta-galactosidase genes galRBM20_1 are provided for industrial production, and can be widely applied to dairy product trade.