37 results about "Ph stability" patented technology

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 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 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.

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 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 invention discloses alpha-L-arabinofuranosidase AraA02173 as well as a truncated body and application thereof, and belongs to the technical field of microorganisms. The invention provides amino acid sequences of AraA02173 and a truncated body thereof and a nucleotide sequence of a coding gene of the AraA02173. Characterization information is provided, and the characterization information includes that CBMs in the enzyme have a key maintaining effect on the temperature, pH stability and enzyme activity of an enzyme catalysis module of the CBMs. The purified enzymes of the AraA02173 and the truncation provided by the invention have obvious alpha-L-arabinofuranosidase activity, 4-nitrophenyl-alpha-L-arabinofuranoside can be degraded, the AraA02173 and the truncation also have beta-xylosidase activity, the specific enzyme activity of the AraA02173 is obviously superior to that of the truncation, and the AraA02173 and the truncation can be used for degrading 4-nitrophenyl-alpha-L-arabinofuranoside. Therefore, the alpha-L-arabinofuranosidase AraA02173 has great development potential, provides powerful theoretical support for preparing commercial enzyme preparations, and is of great significance in broadening related application of the alpha-L-arabinofuranosidase.

Provided in the present invention are an α-amylase mutant having improved enzyme activity, 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, and a preparation method therefor and the use thereof.

Provided are an α-amylase mutant having an improved enzyme activity, 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, and a preparation method therefor and the use thereof.

The present invention provides an α-amylase mutant with enhanced enzyme activity, 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.

The present application relates to the field of agricultural biotechnology, and in particular to the application of Trichoderma chitinase ech2 and its mutants for inhibiting plant pathogenic fungi. The present application determines that the protein with the amino acid sequence shown in SEQ ID NO: 2 is a chitinase, and the chitinase ech2 exhibits excellent temperature adaptability and pH stability. Experiments show that the activity of the enzyme is significantly improved in the range of 20-35 DEG C, and reaches the peak activity at 35 DEG C; the enzyme maintains high activity in a wide range of pH 4-9, and the optimum pH is 5.5. The storage stability is good, the application range is wide, and the growth of plant pathogenic fungi Botrytis cinerea and Fusarium oxysporum is inhibited. The optimum temperature of the improved chitinase mutant ech2-1 is 45 DEG C, which is increased by 10 DEG C compared with the original ech2; the ech2-1 is stable at 4 DEG C-40 DEG C, and is suitable for development as an agricultural chitinase.

The invention relates to beta-glucuronidase as well as a preparation method and application thereof, and belongs to the technical field of enzyme engineering. According to the recombinant beta-glucuronidase disclosed by the invention, a beta-glucuronidase coding gene from Thermobacillus composti is expressed in escherichia coli, so that the recombinant beta-glucuronidase with good hydrolysis specificity, thermal stability and pH stability can be prepared, and glycyrrhetinic acid can be prepared by efficiently degrading glycyrrhizic acid by utilizing the recombinant beta-glucuronidase; the problems that in the prior art, beta-glucuronidase is low in catalytic activity on glycyrrhizic acid, poor in hydrolysis specificity, poor in stability and the like are solved. In the production of glycyrrhetinic acid, glycyrrhizic acid or monoglucose glycyrrhetinic acid is taken as a substrate, methanol is added for assisting dissolution, the conversion efficiency is remarkably improved, the substrate conversion rate can reach 99% or above, and the highest yield can reach 95%. The biotransformation process established by the invention has the advantages of mild reaction conditions, high substrate utilization rate, good product purity and the like, and provides a new thought and method for industrial production of glycyrrhetinic acid.

The present invention discloses a leucine dehydrogenase mutant and its application in the preparation of L-phenylglycine. The leucine dehydrogenase mutant is: using the wild-type leucine dehydrogenase MsLDH shown in SEQ ID NO.1 as a template, aspartic acid D at the 332nd position is mutated to glutamic acid E, glycine G at the 333rd position is mutated to glutamic acid E, and leucine L at the 334th position is mutated to arginine R to obtain the mutant MsLDH-EER, and the amino acid sequence is as shown in SEQ ID NO.2. The present invention obtains a leucine dehydrogenase mutant MsLeuDH with improved catalytic activity and pH stability through molecular modification. Compared with the wild-type MsLeuDH, the conversion rate is 68.0% at 4 h under a substrate concentration of 200 mM. According to the mutant MsLDH-EER provided by the present invention, the conversion rate reaches 99.5% at 3 h, and the e.e. value of the product is greater than 99%.

The invention discloses a phenolic acid decarboxylase mutant for efficiently producing 4-vinyl guaiacol and application of the phenolic acid decarboxylase mutant, and belongs to the technical field of gene engineering and enzyme engineering. The 91 amino acid of a wild type sequence as shown in SEQ ID NO.1 has V-I mutation, and the amino acid sequence of the mutated phenolic acid decarboxylase mutant is as shown in SEQ ID NO.2. Compared with wild type phenolic acid decarboxylase, the phenolic acid decarboxylase mutant obtained by the invention has the advantages that the thermal stability and the pH stability are improved, the optimal temperature of the mutant V91I is increased to 50 DEG C, the optimal temperature of the wild type is only 40 DEG C, and the phenolic acid decarboxylase mutant has better tolerance than the wild type at the temperature of 40 DEG C or above. Meanwhile, the pH stability of the mutant is also remarkably improved, so that the phenolic acid decarboxylase mutant can be better applied to the fields of fermented foods and medicines.

The present invention provides an α-amylase mutant with enhanced enzyme activity, 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.