48 results about "Ph stability" patented technology

The invention discloses a high-activity endoglucanase expression optimized strain and application thereof, and belongs to the technical field of gene engineering and enzyme engineering. According to the present invention, PCR amplification and homologous recombination are adopted to carry out strain construction and expression optimization on endoglucanase tCel5A, and screening is performed to obtain the sAOX1-pSUC2-tCel5A strain; an enzymatic property research finds that the recombinant pPICZA-tCel5A has the optimal temperature of 50 DEG C and the optimal reaction pH of 4.5, and has good thermal stability and low pH stability. The enzyme activity determination result shows that the enzyme activity of the sAOX1-pSUC2-tCel5A after expression optimization is 4632.81 U / mg prot, which indicates that the tCel5A after expression optimization can efficiently degrade cellulose, and has a great application prospect in the fields of agriculture, brewing industry and the like.

The invention belongs to the technical field of biology, and relates to a mutant of horse-derived acylase with high pH stability, a coding gene and application of the mutant in catalytic generation of lauroyl glycine. The horse-derived acylase mutant sequence disclosed by the invention has the advantages of high enzyme activity stability in a wider pH environment, high synthesis efficiency of lauroyl glycine and very high production and application values.

The invention discloses chimeric xylanase XynZT-1-Z5 and a construction method thereof, and relates to the technical field of molecular biology, and the technical key points are as follows: comparing the sequence of xylanase XynZT-1 with the sequence of xylanase from different thermoduric bacteria, analyzing the amino acid conserved site of the xylanase XynZT-1, and replacing the sequence beta5-beta6 of the thermoduric bacteria onto the XynZT-1 to obtain the chimeric xylanase XynZT-1-Z5. The chimeric enzyme XynZT-1-Z5 has efficient overexpression, good solubility and relatively strong temperature and pH stability, is particularly suitable for industrial enzyme catalytic reaction under the conditions of high temperature and extreme pH, and can be widely applied to the food industry, the wine brewing industry, the papermaking industry and the feed industry.

The invention discloses a glucose oxidase mutant with improved acid resistance and heat resistance as well as a construction method and application of the glucose oxidase mutant, and belongs to the technical field of bioengineering. According to the present invention, glucose oxidase AsGODP derived from Aspergillus scleroticus is adopted as a female parent, and Glu148 and Val179 are subjected to synchronous mutation to form Lys148 and Ala179 so as to obtain the mutant E148K / V179A; experiments show that the pH stability, the thermal stability, the half-life period at 75 DEG C and the catalytic performance of the mutant E148K / V179A are obviously improved compared with those of wild AsGODP. According to the catalytic performance, when the mutant E148K / V179A is applied to bread baking, the gluten degree of dough can be effectively improved under the fermentation condition, the bread texture is improved, and therefore the mutant E148K / V179A shows huge development potential in the bread baking industry.

The invention relates to the technical field of enzyme engineering, and particularly discloses a preparation method of immobilized sucrose phosphorylase (SPase) with low cost and high stability. According to the method, epoxy resin is synergistically modified through gallic acid (GA) and a polyethyleneimine-chitosan copolymer (PEI-CS), a covalent bond-hydrogen bond-ionic bond ternary cross-linked network is formed, and efficient immobilization of SPase is achieved. The preparation method comprises the following steps: preparation of a PEI-CS copolymer, preparation of a GA-PEI-CS modification liquid, modification treatment of epoxy resin, immobilization of SPase and determination of enzyme activity. The prepared immobilized enzyme has high enzyme activity retention rate (96.5%), wide temperature and wide pH stability (high activity is kept at 60 DEG C and pH 4.0-10.0), long reuse life (82.1% of enzyme activity is kept after 50 times of reuse) and low cost (26.7 yuan / kg), and can be widely applied to the fields of food industry, cosmetic industry and biological pharmacy.

The invention discloses a synthesis method of an amino-acid-based MOFs (Metal-Organic Frameworks) derived nano-enzyme, and relates to the technical field of nano-enzyme synthesis, the synthesis method of the amino-acid-based MOFs derived nano-enzyme comprises the following steps: step 1, selecting proper metal ions and organic ligands; step 2, ultrasonic dispersion; step 3, precipitate drying; and step 4, activating treatment of the nano enzyme. The MOFs-derived nano-enzyme with alkaline phosphatase activity is synthesized by taking natural amino acid as a ligand and one of ions of zirconium, copper and iron as a metal node and introducing defects by a method of adding an acidic regulator in synthesis, and the crystal structure of the nano-enzyme is not changed under the introduction of the defects, so that the alkaline phosphatase activity of the MOFs-derived nano-enzyme is improved. The MOFs-derived nano-enzyme has the advantages that the MOFs-derived nano-enzyme is modified, the catalytic hydrolysis activity of the MOFs-derived nano-enzyme on phosphate substrates is greatly improved, good substrate specificity is shown, the structure of the MOFs-derived nano-enzyme does not change after long-term incubation under acidic, alkaline and high-temperature conditions, and compared with natural enzyme, the MOFs-derived nano-enzyme has good stability, pH stability and reusability.

The invention relates to a beta-galactosidase mutant with improved thermal stability and pH stability, and belongs to the technical field of enzyme engineering. The beta-galactosidase derived from Kluyveromyces lactis is subjected to molecular modification, a potential mutation site is determined by using an alanine scanning strategy, beta-galactosidase mutants Pro433Ala and Asp441Ala of which the thermal stability and the pH stability are simultaneously improved are obtained through site-directed mutagenesis screening, the catalytic efficiency of the mutants is improved to 1.03-1.18 times compared with that of the mutants before optimization, and the beta-galactosidase mutant can be used for preparing beta-galactosidase. Wherein the maximum half-life period of the mutant Asp441Ala under the condition of 50 DEG C reaches 91.5 minutes and is increased by 213.4% compared with that of a wild type, the problems of poor catalytic thermal stability and poor pH stability of beta-galactosidase in the prior art are solved, and a brand-new tool is provided for obtaining galactooligosaccharide by using beta-galactosidase to hydrolyze lactose.

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 present invention relates to the field of biotechnology, and specifically relates to β-1,4-endoxylanase XlyAE10, its encoding gene and applications thereof. The xylanase XlyAE10 provided by the present invention is a β-1,4-endoxylanase XlyAE10 with excellent properties, good pH stability and heat resistance. The optimal temperature of this enzyme is 60.0 °C, and the optimal pH value is 5.5. It still maintains 50% of its activity within the range of pH 4.0 - 9.0, and has 93.26% of its enzyme activity at 65.0 °C. It can be applied to high-temperature biotechnology fields such as food, feed, textile, pulp bleaching and energy development, and has broad application prospects.

The invention discloses salt-resistant and alkali-resistant xylanase and application thereof, and relates to the technical field of biology. The amino acid sequence of the salt-resistant and alkali-resistant xylanase is as shown in SEQ ID NO: 2. According to the invention, a novel salt-resistant and alkali-resistant gene cwp6-xyn10 is obtained from the Qaihu saline-alkali soil by utilizing a metagenome technology. Then, the gene is subjected to heterologous expression in E.coli, and enzymatic properties are analyzed. Enzymatic characterization shows that the CWP6-Xyn10 is a salt-resistant, alkali-resistant and high-activity xylanase, and has good salt resistance and pH stability.

The invention discloses an acidophilic and halophilic GH12 xyloglucanase gene as well as an expression protein and application thereof. The DNA (Deoxyribose Nucleic Acid) sequence of the acidophilic and halophilic GH12 xyloglucanase gene is as shown in SEQ ID NO.1, and the amino acid sequence of the acidophilic and halophilic xyloglucanase expressed by the acidophilic and halophilic GH12 xyloglucanase gene is as shown in SEQ ID NO.2. The xyloglucanase disclosed by the invention shows the maximum enzyme activity at the pH value of 4.0 and the temperature of 40 DEG C and has remarkable pH stability, and the activity is still kept at 80% or above in the presence of 1.71 M NaCl and 10% (v / v) ethanol. The acidophilic and halophilic GH12 xyloglucanase disclosed by the invention can be used for effectively degrading xyloglucan and producing xyloglucan oligosaccharide, and is expected to become a catalyst in food and biological industries.

The present invention discloses a β-1,4-endoxylanase derived from the metagenome of Asian elephant feces, its encoding gene and applications, which relates to the technical field of genetic engineering. The genome of a Prevotella bacterium with a completeness of 97.47% and a contamination rate of 0 was assembled by using metagenomic binning technology. The β-1,4-endoxylanase (EC 3.2.1.8) gene was obtained through annotation in the KEGG Enzyme database. The nucleotide sequence of the β-1,4-endoxylanase encoding gene is shown as SEQ ID NO.3, and its amino acid sequence is shown as SEQ ID NO.4. Compared with the β-1,4-endoxylanase derived from fungi, this enzyme has good thermal stability and pH stability, can significantly increase the growth rate of reducing sugars in the in vitro enzymatic hydrolysis of soybean meal, is beneficial to the pretreatment of soybean meal raw materials, and has application value for the preparation of feed using soybean meal.

The invention discloses novel beta-1, 4-endo-xylanase as well as a coding gene and application thereof, and relates to the technical field of gene engineering. A genome of a strain of Lachnospiraceae bacteriaceae NK4A136 bacteria with the integrity of 96.44% and the contamination rate of 0 is assembled by using a metagenome binning technology, a beta-1, 4-endo-xylanase gene is obtained through annotation of a KEGG Enzyme database, the nucleotide sequence of the beta-1, 4-endo-xylanase encoding gene is shown as SEQ ID NO.3, and the amino acid sequence of the beta-1, 4-endo-xylanase encoding gene is shown as SEQ ID NO.4. The invention further discloses a preparation method of the beta-1, 4-endo-xylanase encoding gene. Compared with fungus-derived xylanase, the xylanase has good thermal stability and pH stability, can significantly improve the in-vitro enzymolysis reducing sugar growth rate of bran, is beneficial to pretreatment of bran raw materials, and has application value in preparation of feed from bran.

The invention discloses a zearalenone degrading enzyme as well as a coding gene and application thereof, and belongs to the technical field of biology. The zearalenone degrading enzyme obtained by the invention is a brand-new enzyme, has better temperature and pH stability, has stronger degradation capacity on mycotoxin zearalenone, is high in degradation speed, and can be widely applied to enzymolysis of zearalenone. Therefore, a new enzyme preparation is provided for biodegradation of zearalenone, and the enzyme can be used in the industrial fields of agriculture, feed, food and the like and has good application potential, so that a good technical foundation is laid for ensuring feed safety, and harm caused by zearalenone pollution to human and livestock health is reduced.

The present invention discloses a glucose oxidase mutant with improved acid and heat resistance, as well as a construction method and application thereof, and belongs to the field of bioengineering technology. The present invention uses glucose oxidase AsGODP derived from the fungus Aspergillus sclerotiicarbonarius as the parent, and synchronously mutates Glu148 and Val179 to Lys148 and Ala179 to obtain the mutant E148K / V179A. Experiments have found that the mutant E148K / V179A has significant improvements in pH stability, thermal stability, half-life at 75°C and catalytic performance compared with the wild-type AsGODP. Based on the catalytic performance, the mutant E148K / V179A is used in bread baking, which can effectively increase the dough gluten under fermentation conditions and improve the texture of bread, thereby showing great development potential in the bread baking industry.

The utility model relates to an experiment device for simulating organism pH stability, which comprises a medicament bottle, a magnetic stirrer, a test bottle, a delivery pipe, a peristaltic pump and a ph sensor, the test bottle is arranged on the magnetic stirrer, the test bottle is communicated with the medicament bottle through the delivery pipe, and the ph sensor is arranged in a test cavity of the test bottle. The peristaltic pump drives the conveying pipe to convey the medicament in the medicament bottle into the test bottle, and the magnetic stirrer uniformly stirs the test material in the test cavity, so that the ph sensor can accurately and quickly measure the ph value of the test material, the influence of the original color of the test material is avoided, the test value is more accurate, and the test effect is good. Meanwhile, an operator can be prevented from being in contact with a test material, the test risk is effectively reduced, and the safety is high.

Provided are novel bio-based surfactant derivatives with enhanced pH stability, and their use in a variety of consumer products. Methods of preparing these surfactant derivatives are also provided.

The invention discloses a salt-tolerant ethanol-tolerant beta-1, 3-1, 4-glucanase gene, an expression protein and application, the DNA (Deoxyribose Nucleic Acid) sequence of the salt-tolerant ethanol-tolerant beta-1, 3-1, 4-glucanase gene is respectively as shown in SEQ ID NO.1, and the amino acid sequence of the salt-tolerant ethanol-tolerant beta-1, 3-1, 4-glucanase expressed by the salt-tolerant ethanol-tolerant beta-1, 3-1, 4-glucanase gene is as shown in SEQ ID NO.2. The invention further discloses a preparation method of the salt-tolerant ethanol-tolerant beta-1, 3-1, 4-glucanase gene. The beta-1, 3-1, 4-glucanase TaGlu16B disclosed by the invention shows the maximum enzyme activity when the pH value is 5.0 and the temperature is 50 DEG C, and has remarkable pH stability (the enzyme activity is kept about 94%, 72% and 86% respectively when the pH values are 4, 5 and 6). Besides, when the concentration of NaCl in the beta-1, 3-1, 4-glucanase TaGlu16B is 2% and the concentration of NaCl in the beta-1, 3-1, 4-glucanase TaGlu16B is 15%, the activity of the TaGlu16B reaches 116.9% and 113% respectively. In ethanol with the concentration of 0-20%, TaGlu16B can keep the activity of 70% or above, beta-glucan can be effectively degraded, the filtering time in the beta-glucan saccharification process in the brewing industry is shortened, the viscosity in the beta-glucan saccharification process in the brewing industry is reduced, and therefore the food manufacturing cost is effectively reduced, and TaGlu16B is expected to become a catalyst in the food and biological industry.

The application discloses a monomerized pyrimidine nucleoside phosphorylase mutant and a construction method and application thereof, and belongs to the field of enzyme engineering and biological catalysis technology.The mutant is obtained by amino acid substitution mutation of wild-type pyrimidine nucleoside phosphorylase shown in SEQ ID NO:1, and the amino acid sequence is shown in SEQ ID NO:2.The mutant is transformed into a stable monomer form by dimer interface remodeling and hinge region stabilization of the closed active conformation, the natural dimer PyNP is transformed into a stable monomer form, and the catalytic activity of the mutant to uridine, 2'-deoxyuridine and similar substrates is maintained in the monomer state.Compared with the wild-type enzyme, the mutant has lower oligomer dependence, better temperature stability, pH stability and storage stability, and can be used for biological catalytic synthesis of nucleosides and nucleoside analogs.

The invention belongs to the technical field of immobilized enzymes, and particularly relates to a preparation method and application of immobilized D-psicose 3-epimerase. Comprising the following steps: (1) generating a composite carrier from aminated mesoporous silica and chitosan; (2) modifying the composite carrier with succinic anhydride to obtain a closed carrier; (3) regenerating the closed carrier by using a sodium carbonate solution to obtain a regenerated carrier; (4) carrying out cross-linking on glutaraldehyde serving as a cross-linking agent and D-psicose 3-epimerase, so as to obtain a cross-linked enzyme solution; and (5) carrying out cross-linking immobilization on the regenerated carrier and a cross-linked enzyme solution to obtain the immobilized D-psicose 3-epimerase. The immobilized D-psicose 3-epimerase disclosed by the invention is high in enzymatic activity, good in thermal stability, good in pH stability, excellent in reusability, relatively high in conversion rate when being applied to isomerization preparation of D-psicose from D-fructose, capable of remarkably increasing the yield of D-psicose, and suitable for continuously converting D-fructose to generate D-psicose.

The application belongs to the field of bioengineering, and particularly relates to a beta-1,6-glucanase and application thereof, more particularly to a beta-1,6-glucanase, a composition containing the same, and a method for preparing soluble yeast glucan by using the enzyme or the composition. The amino acid sequence of the beta-1,6-glucanase provided by the application comprises the sequence shown in SEQ ID NO. 1. The beta-1,6-glucanase provided by the application has a wide working temperature range and pH range, good thermal stability and pH stability, and a wide use range, and solves the problems of complex environment, poor pH and temperature tolerance in the industrial application of the beta-1,6-glucanase. Meanwhile, the combination of the beta-1,6-glucanase and beta-1,3-glucanase provided by the application is used to efficiently produce soluble yeast glucan, the reaction condition is mild, and an effective solution is provided for the degradation of natural complex beta-1,3 / 1,6-glucan.

A high-temperature-resistant xylanase mutant with improved pH stability and application thereof, the mutant is one of two mutants obtained by mutating Glu53 and Ser316 two amino acid sites of a xylanase JaXyl10A from Jaapia argillacea a xylanase JaXyl10A from Aspergillus kawachi as a parent, and is one of two mutants obtained by mutating Glu53 and Ser316 two amino acid sites, namely E53Y or S316N; the amino acid sequence of the mutant E53Y is shown as SEQ ID NO: 2; the amino acid sequence of the mutant S316N is shown as SEQ ID NO: 3. The obtained xylanase mutants E53Y and S316N have greatly improved pH tolerance and thermal stability.

This invention belongs to the field of biotechnology and discloses a glucosylamylase mutant. The amino acid sequence of the glucosylamylase mutant is shown in SEQ ID NO: 1, or an amino acid sequence with more than 90% homology to the above sequence. Compared with the wild type, the glucosylamylase of this invention exhibits significantly improved pH stability, a wider temperature tolerance range, and significantly enhanced heavy metal resistance, making it more suitable for complex industrial environments, especially for hypoglycemic treatments involving heavy metals and large pH fluctuations, such as glutamate mother liquor, and has high industrial application value.

The invention discloses a glucose isomerase mutant, a coding gene thereof, a recombinant vector constructed by the coding gene, a recombinant genetically engineered bacterium obtained by converting the recombinant vector, and application of the glucose isomerase mutant in catalyzing glucose to generate fructose. The glucose isomerase mutant with good thermal stability, good pH stability and high fructose conversion rate is obtained by performing site-specific mutagenesis on the wild glucose isomerase XAA and is successfully used for catalyzing glucose to generate fructose, and the conversion rate and reaction speed of the glucose isomerase mutant are both superior to those of the wild glucose isomerase XAA. The glucose isomerase mutant shows excellent application prospects and can be used for directly preparing 55% high fructose corn syrup.

The invention discloses an aminopeptidase APs8-A297V, an aminopeptidase APs8-A599V, and an application of the aminopeptidase APs8-A297V and the aminopeptidase APs8-A599V in degradation of bitter peptides. The amino acid sequence of the aminopeptidase APs8-A297V is as shown in SEQ ID NO.5, and the amino acid sequence of the aminopeptidase APs8-A599V is as shown in SEQ ID NO.6. The invention further discloses a preparation method of the aminopeptidase. The aminopeptidase APs8-A297V and the aminopeptidase APs8-A599V are obtained through site-specific mutagenesis of the aminopeptidase APs8, optimization of substrate specificity and remarkable improvement of catalytic activity are achieved, good temperature stability, pH stability and excellent high-salt tolerance are shown, accurate hydrolysis can be achieved according to bitter peptide characteristics of different food source proteins, and the application prospect is wide. The bitter taste of the food is reduced to the maximum extent, the quality of the food is improved, and theoretical and practical support is provided for diversified application of the aminopeptidase in the food industry.

The invention relates to the technical field of enzyme engineering, and particularly discloses a high-tolerance PET hydrolase as well as a preparation method and application thereof, the high-tolerance PET hydrolase is TbPETase, and the amino acid sequence of the high-tolerance PET hydrolase is shown as SEQ ID No.1. The TbPETase disclosed by the invention, as a novel PET hydrolase, shows remarkable degradation capacity under the conditions that the temperature is 60 DEG C and the pH value is 8, solves the problem that the existing PET enzyme is insufficient in activity under high-temperature and neutral / alkaline environments, and has a wide application prospect. Compared with the prior art, the TbPETase has the advantages that the TbPETase has excellent temperature adaptability and pH stability, PET can be efficiently degraded under more harsh industrial conditions, and a more feasible solution is provided for plastic recovery and environmental protection.

The invention relates to the technical field of biology, in particular to beta-1, 4-endo-xylanase XlyAE10, a coding gene and application of the beta-1, 4-endo-xylanase XlyAE10, the beta-1, 4-endo-xylanase XlyAE10 is excellent in property and good in pH stability and heat resistance, the optimum temperature of the xylanase XlyAE10 is 60.0 DEG C, the optimum pH value of the xylanase XlyAE10 is 5.5, 50% of activity is still kept in the pH range of 4.0-9.0, the enzyme activity of the xylanase XlyAE10 at the temperature of 65.0 DEG C is 93.26%, and the xylanase XlyAE10 has the advantages that the xylanase XlyAE10 can be used for preparing the xylanase The method can be applied to high-temperature biotechnology fields such as food, feed, textile, paper pulp bleaching and energy development, and has a wide application prospect.

The present invention provides an α-amylase mutant with improved thermal stability and / or low pH stability, a polynucleotide encoding the α-amylase mutant, a recombinant expression vector containing the polynucleotide, a host cell expressing the α-amylase mutant, a composition containing the α-amylase mutant, a method for preparing the same, and its use.

This invention discloses a method for preparing recombinant dextranase from Chaetomium globosum and its uses. The amino acid sequence of the recombinant dextranase is shown in SEQ ID NO.2 or SEQ ID NO.4, and the nucleotide sequence of its encoding gene is shown in SEQ ID NO.1 or SEQ ID NO.3. The optimal pH of the recombinant dextranase is 4.5-7.0, and the optimal reaction temperature is 45-60℃. + K + and Ca 2+ It has an activating effect on enzyme activity, Mg 2+ NH4 + and Mn 2+ It had no significant effect on enzyme activity, Fe 3+ Zn 2+ Cu 2+ and Co 2+ It has an inhibitory effect on enzyme activity. Furthermore, this enzyme exhibits excellent pH stability, good thermal stability, and anti-interference ability, making it well-suited to the application requirements of the food, pharmaceutical, and chemical industries.

The present invention discloses an arginine deiminase mutant with high pH stability and its application in tumor treatment. The arginine deiminase mutant provided by the present invention has improved pH stability, and after PEG modification, still maintains good pH stability, solves the problems of low storage stability of arginine deiminase and low stability under physiological pH 7.4, especially the mutant K208R / K258H / L318F, the enzyme activity is 110% of the parent, the pH stability and pH stability after PEG modification are good.