42 results about "Heat inactivation" patented technology

The invention relates to the field of structural catalysts, in particular to an activated carbon coating / foam silicon carbide catalyst with a three-dimensional communicated structure and a preparation method for the catalyst. The invention aims to solve the problems that hole opening is discontinuous, the catalyst and reaction products are separated, a heat transfer and mass transfer effect is poor and the like in the prior art. By taking foam silicon carbide as a catalyst carrier, an activated carbon coating covers on the surface of the foam silicon carbide, wherein the activated carbon coating is between 0.1 micron and 500 microns thick, and a metal catalysis active component is loaded on the activated carbon coating. The activated carbon coating is prepared on the surface of the foam silicon carbide with the three-dimensional communicated structure, then, the metal catalysis active component is loaded, and activating treatment is performed on the metal catalysis active component to obtain the catalyst. According to the activated carbon coating / foam silicon carbide catalyst, holes in the catalyst carrier are totally communicated, thus, an enclosure space does not exist, and a heat transfer and mass transfer process of the chemical reaction can be strengthened. The activated carbon coating / foam silicon carbide catalyst has the characteristics that the temperature field distribution of the catalytic reaction is uniform, the heat inactivation rate is low, the pressure drop is low and the like.

The invention relates to genetical modification of DNA polymerase to reduce its innate selective sequence-related discrimination against incorporation of fluorescent dye-labeled ddCTP and ddATP in the enzymatic reaction for preparation of samples for automated florescent dye-labeled terminator DNA sequencing. The modified DNA polymerases are more resistant to heat inactivation and are more effective in dideoxynucleotide incorporation than current DNA polymerases.

The invention provides a black tea concentrated solution and a preparation method thereof. Specially, the preparation method of the black tea concentrated solution comprises the following steps: (1) leaching: taking a black tea and leaching the taken black tea with water which is 20-40 times as much as the black tea so as to obtain a leaching solution, wherein the water temperature is 60-90 DEG C; (2), performing enzymatic hydrolysis: sequentially adopting esterases for performing enzymatic hydrolysis on the leaching solution obtained in the step (1), adopting tannase for performing enzymatic hydrolysis on the leaching solution on which enzymatic hydrolysis is performed with the esterases, and adopting protease for performing enzymatic hydrolysis on the leaching solution on which enzymatic hydrolysis is performed with the tannase; (3) adding a compounded emulsifying stabilizing agent: performing heat inactivation on the leaching solution on which enzymatic hydrolysis is performed, cooling the leaching solution on which heat inactivation is performed, and adding the compounded emulsifying stabilizing agent which is 0.1-0.5% as many as the weight of the black tea obtained in the step (1), and uniformly stirring the leaching solution and the compounded emulsifying stabilizing agent, wherein the compounded emulsifying stabilizing agent consists of cane sugar fatty acid ester, glyceryl monostearate and sodium hexametaphosphate; (4) homogenizing: sequentially homogenizing the leaching solution at the temperature of 40-50 DEG C and the first-class pressure of 190-210MPa, and then homogenizing the homogenized leaching solution at the temperature of 40-50 DEG C and the second-class pressure of 20-30MPa; and (5) post-treating: centrifuging the homogenized leaching solution, performing ultrafiltration and concentrating the ultra-filtered leaching solution so as to obtain the concentrated solution, regulating the pH value to be 6-6.5, performing sterilization, and filling so as to obtain the black tea concentrated solution.

The invention relates to a graphene and protein composite film based on non-covalent modification and a preparation method thereof. The composite film comprises a silica substrate, single-layer graphene and a protein film. The preparation method comprises the following steps: transferring the single-layer graphene film grown through chemical vapor deposition onto the surface of the silica substrate, removing a photoresist on the surface of the graphene film to leave single-layer graphene on the surface of the silica substrate; and dropwise adding the a protein solution onto the surface of the single-layer graphene and carrying out heat inactivation treatment at 60-90 DEG C for 1-10 min to form a protein film on the surface of the single-layer graphene. Non-covalent modification of the protein film is realized on the surface of graphene through the heat inactivation method. Thickness of the graphene-protein film can be controlled to nanoscale. The film is uniform. The preparation method is simple to operate and easy to realize. The protein film surface has amino group and carboxyl group and can be used as a platform for follow-up biomolecule diagnosis. The product has a good application prospect.

The invention provides a crystallization process for extracting L-tryptophan from fermentation broth. The crystallization process comprises the following steps: continuously applying 50W ultrasound to crystallize concentrated fermentation broth at the temperature of 4 DEG C after the fermentation broth is treated by heating inactivation, microfiltration, ultrafiltration and rotary evaporation, wherein the ultrasound action time is 15-20min, so that tryptophan concentrated solution is quickly developed into minute crystals with uniform size from original crystal nucleuses with different sizes under the ultrasonic cavitation; then, allowing standing still for 1h at constant temperature of 4 DEG C, performing suction filtration on obtained suspension, and drying, so as to obtain a finished product. The parameters of crystallization rate, the conductivity change rate, the product yield, quality and purity and the like of the crystallization process and the existing common crystallization process are compared. The crystallization process provided by the invention mainly aims at solving the problems of multi-times of crystallization, long crystallization period, bigger crystals, non-uniform size, undesirable crystallizing quantity and the like existing in the traditional tryptophan extraction process, therefore, the crystallization rate is improved, the crystallization period is shortened, the L-tryptophan product yield is improved, and the purity is not influenced.

The invention provides a model for predicting a viable bacteria survival amount of bacillus coagulans under dynamic temperature change in a food heat treatment processing process and application of the model, and the established model can predict the viable bacteria survival amount of the bacillus coagulans in the medium after thermal inactivation according to initial concentrations of the bacillus coagulans in different media and real-time temperature change conditions of the bacillus coagulans in a heat inactivation process. The method provided by the invention is suitable for the thermal inactivation process of bacillus coagulans in any food processing, and provides a rapid, simple and convenient technical method for evaluating the stability of bacillus coagulans in the functional foodprocessing process. According to the method, a traditional microbiological detection means is not needed, and the viable count in the functional food processing process can be directly predicted onlyby knowing the temperature change condition, the used time and the initial bacillus coagulans count in the functional food processing process.

The invention discloses a method for multistage purification of nuclease P1, that is, performing multistage purification of nuclease P1 crude enzyme solution through ultrafiltration membrane ultrafiltration, heat inactivation and resin impurity removal. The method of the invention can efficiently separate and purify the nuclease P1, and the enzyme recovery rate of the nuclease P1 reaches 82.6 percent; and the method has low cost and is applicable to large-scale industrial production. At the same time, the purity of the nuclease P1 obtained by the method of the invention is greatly improved, the specific activity is 7.3 times that of the crude enzyme solution, and there are few impurities, so it can be used in the food industry.

The invention discloses a steam moist-heat inactivation method for soybean quarantine pests. When the method is used for production inactivation of main quarantine pests in soybean processing byproducts such as tofu skin, impurities and leftovers, the method comprises the following steps of: crushing the soybean processing byproducts such as the tofu skin, the impurities and the leftovers carrying the quarantine pests to the granularity of less than or equal to 3 millimeters through a crusher, putting the processing byproducts into equipment with temperature of more than or equal to 85 DEG C and relative humidity of more than or equal to 95 percent, and keeping the processing byproducts in the equipment for more than or equal to 4 minutes so that the quarantine pests are completely inactivated. The adopted steam moist-heat inactivation method is simple, convenient, economic and environment-friendly, and can be widely applied to the production inactivation of the quarantine pests in the imported soybean processing byproducts such as the leftovers, the impurities and the tofu skin and feed.

The invention belongs to the technical field of protein renaturation and especially relates to a preparation method for partially inactivated chymosin. The preparation method comprises the following steps: (1) placing a chymosin solution containing ectoine under the temperature at 61-70 DEG C and treating for 1-20min, thereby acquiring the partially inactivated chymosin, and (2) quickly cooling the partially inactivated chymosin prepared in the step (1) to 4 DEG C, standing by and refrigerating for 0-42h, thereby acquiring the chymosin after renaturation. The method is different from the treating method for high concentration urea, and the like; a heat inactivation method is adopted for preparing the partially inactivated chymosin; the operation is simple and easy, the repeatability is high and the state of the partially inactivated chymosin is more approximate to the heat inactivation state of enzyme; the inactivated chymosin prepared according to the method has the characteristics of obvious renaturation effect, high enzyme activity after renaturation, and the like.

The invention relates to the usage of a 2',5',6',7'-tetrahydroxyflavanonol and the derivative in treating pyohemia, belonging to flavanonol compound THF, which is extracted and separated from baikal skullcap root of Chinese herbal medicine. Through experiment showing, the THF has the advantages that: the THF has direct neutralization effect and reveals better dose effect relationship; the THF also reveals better dose effect relationship upon inhibition of RAW 264.7 cells activation LPS stimulation; the THF can lower LPS level in blood of LPS blood symptom model animal in vivo; the THF also has obvious protection effect upon bacterial sepsis model mouse caused by heat-inactivation escherichia coli with lethal dose; the THF has good application prospect under the condition of lacking effective means treating pyohemia in prior study.

The invention belongs to the field of gene engineering, and relates to novel alkaline phosphatase and a preparation method thereof. The cDNA sequence of low temperature alkaline phosphatase shown as SEQ ID NO 1 in a sequence table is cloned to a vector for genetic engineering, and expressed to obtain the low temperature alkaline phosphatase. According to codon bias of Escherichia coli, the DNA sequence of the TAB5 low temperature alkaline phosphatase is transformed, so that the DNA sequence is highly expressed in the Escherichia coli; the alkaline phosphatase is purified by nickel affinity chromatography and ion exchange chromatography; and more than 90mg of TAB5 alkaline phosphatase with the purity of over 99 percent is obtained from each liter of Escherichia coli liquid finally. The invention can be applied to research in the field of molecular biology of the field of life science, particularly multi-step reaction for heat inactivation of alkaline phosphatase, such as sample treatment before DNA sequencing and the like.

The invention discloses an improved adenovirus vector system and a virus preparation method. The system takes a pDONR221 vector as an initial vector to make improvement, and multiple cloning sites and an IRES-GFP fragment are inserted. The system combines enzyme digestion connection and recombination reaction technologies, can efficiently construct a vector, and also reduces the reagent cost. The invention also discloses an improved method of purification following after enzyme digestion of the virus vector. The method abandons traditional purification methods adopting phenol, chloroform and isoamyl alcohol, and uses a conventional DNA recovery column or direct heat inactivation method. The method is simple and feasible, shortens the operation time, reduces the material cost, and has no need for toxic phenol and chloroform reagents. The adenovirus system combining the two aspects has improved preparation efficiency and reduced cost, and still maintains high efficiency in infected cells.