31results about How to "Good pH tolerance" patented technology

The invention discloses a polyvinyl alcohol coating chromatography stationary phase as well as a preparation method and application thereof. The preparation method comprises the following steps: a, preparing a polyvinyl alcohol aqueous solution; b, coating the surface of each spherical particle, namely, adding the spherical particles into the polyvinyl alcohol aqueous solution obtained in the step a, stirring the spherical articles at 300 to 1500rpm so as to uniformly mix the spherical articles and the aqueous solution; and c, washing and drying, namely, filtering a reaction system in the step b, washing a solid product by utilizing water, and performing vacuum drying on the solid product to be used as packing stuffing. The polyvinyl alcohol coating chromatography stationary phase and the preparation method have the advantages that the coating-type material is prepared by utilizing a physical coating principle, and the design concept is novel and environment-friendly. The coating process is completed in the aqueous solution system, the operation process is simple and convenient, and the reaction condition is moderate. The technology of the preparation method is wide in application range, a compound of the needed functional group is added in the polyvinyl alcohol aqueous solution to perform the coating, the stationary phase of any function can be prepared, and a wide development space is provided for the polyvinyl alcohol immobilization stationary phase.

The invention discloses a thermophilic recombinant type II pullulanase and its application, belonging to the technical field of genetic engineering. The present invention obtains a thermophilic recombinant type II pullulanase by heterologously expressing type II pullulanase in Escherichia coli. The optimum temperature is 95°C, and the remaining enzyme activity is greater than 50% when incubated at 95°C for 10 hours. It can exhibit high specific enzyme activity under strong reducing conditions. For example, adding DTT to the culture environment can make Sumo‑ pull Py The specific enzyme activity is increased by 237.2%. The present invention also provides type II pullulanase Sumo-Pul Py The combined truncation mutant △28N+△791C, the specific enzyme activity of the mutant enzyme is 32.18±0.92U / mg, which is 5.99 times that of the wild enzyme, and has important industrial application value and potential.

The invention relates to the field of gene engineering, in particular to alkaline salt-tolerant pullulanase PulA and a gene and application thereof. The amino acid sequence of the alkaline salt-tolerant pullulanase PulA is as shown in SEQ ID No. 1, and the nucleotide sequence of the genome encoding gene PulA for encoding the pullulanase is as shown in SEQ ID No. 2. The invention further relates to a recombinant vector and a recombinant strain which contain the gene. The alkaline salt-tolerant pullulanase PulA has the advantages that the optimum pH of the pullulanase PulA is 9.0, and the residual enzyme activity of the pullulanase PulA when the pH is 10.0 is 77%; the optimum reaction temperature of the pullulanase PulA is 50 DEG C, the residual enzyme activity of the pullulanase PulA is 50% in the presence of 0.25-3.0M NaCl, and the pullulanase PulA is quite stable under 3M and 4M NaCl; the pullulanase PulA is alkaline, salt-tolerant and applicable to industrial fields such as detergent and food.

The invention relates to the field of genetic engineering, and provides a salt-tolerant and organic solvent-tolerant low-temperature alkaline esterase EstSL3, a genome coding gene estSL3 and a recombinant vector and a recombination strain comprising the gene, the esterase EstSL3 comes from halophilic and basophilic bacteria, the amino acid sequence of the esterase EstSL3 is shown as SEQ ID NO.1, and the nucleotide sequence of the genome coding gene estSL3 of the esterase is shown as SEQ ID NO.2. The esterase EstSL3 is adapted to pH9.0 and the reaction temperature of 30DEG C best, and the esterase EstSL3 still has about 70 percent of enzyme activity under 0DEG C, which indicates that the enzyme is a low-temperature esterase. Under the existence of 0.5 to 4.0M NaCl, more than 98 percent of enzyme activity remains, and moreover, under the concentration of 4M and 5M NaCl, the esterase EstSL3 is highly stable. The esterase disclosed by the invention has the characteristics of low temperature, alkalinity, salt tolerance, detergent tolerance and organic solvent tolerance, and can be applied in industrial fields such as fine chemical, pharmacy, detergents and food.

The invention discloses a cationic flocculant and a preparation method thereof. The cationic flocculant is polymerized from 10-15 parts by weight of melamine, 40-65 parts by weight of glyoxal, 5-10 parts by weight of catalyst, 0.1-0.5 part by weight of polymerization inhibitor and 30-60 parts by weight of water. The cationic flocculant provided by the invention has the advantages of good stability and excellent resistance to acids and bases; and the cationic flocculant is used for substituting for the melamine resin type flocculants used at present such as polyacrylamide (PAM), dimethyl diallyl ammonium chloride, melamine-formaldehyde, dicyandiamide-formaldehyde condensation polymer and the like; therefore, an excellent flocculating settling effect is achieved while the dosage is reduced.

The invention discloses a disperse dye composition. The composition is composed of a compound A and a compound B, and a general formula (I) of the compound A and a general formula (I) of the compoundB are as shown in the specification. The invention further discloses a disperse dye product comprising the disperse dye composition, and a mass ratio of the compound A to the compound B in the disperse dye composition is (90:10)-(10:90). The disperse dye product further comprises one or more of a conventional dye, a dispersing agent and an auxiliary agent, a mass ratio of the conventional dye to the composition is (5:95)-(90:10), a mass ratio of the dispersing agent to the composition is (20:80)-(80:20), and a mass ratio of the auxiliary agent to the composition is (1:1000)-(3:100). The invention further discloses application of the disperse dye product to fiber products, especially application to polyester and blended products of polyester and cotton, acrylic fibers, wool, cellulose acetate fibers and nylon.

The invention discloses a fresh-keeping agent for fresh edible mushrooms, relates to a fresh-keeping agent for fresh edible mushrooms, prepared by compounding gloeostereum extract, auricularia auricula polysaccharide liquid and Nisin, and a preparation method thereof, belonging to the field of agricultural product processing, storage and fresh-keeping. The fresh-keeping agent comprises the following raw materials in percentage by mass of 6% of gloeostereum entity extract, 1.2% of auricularia auricula polysaccharide liquid, 1% of Nisin and 91.8% of distilled water by compounding. According to the invention, the fresh-keeping agent prepared by compounding several natural extracts has a good antibacterial effect, and inhibits escherichia coli and staphylococcus aureus and the like as the representatives of positive and negative spoilage microorganisms in food, so that the preservation period of edible mushrooms is prolonged, therefore, the fresh-keeping agent has a practical application value, and facilitates the improvement of the whole food preservation level.

The invention discloses an immobilization method of sucrose isomerase, and belongs to the technical field of bioengineering. According to the method, recombinant bacillus brevis is taken as production strain to produce the sucrose isomerase; then immobilization is performed; the enzyme activity is 35.2 U / g after immobilization; the enzymatic activity recovery reaches 70.3 percent; the optimum temperature of immobilized enzyme is 40 DEG C (30 DEG C for free enzyme); and the optimum pH is 4.5 (6.0 for free enzyme); the fact indicates that the immobilized enzyme has better temperature and pH tolerance. Sucrose concentration at 600g*L <1> is taken as a substrate, and the maximum product yield can reach 87.8 percent. After conversion is continuously performed for 16 times under the optimum conversion condition, the product yield is still 87.52 percent, and the fact indicates that the immobilized enzyme has good operation stability and high isomaltulose synthesis capability. The immobilization method is simple to operate and low in cost, and provides a reference for industrial application.