41results about How to "Good acid and alkali tolerance" patented technology

The invention discloses preparation and application of a hollow spherical-segment-shaped mesoporous silica / chloroperoxidase nanoreactor. According to the nanoreactor, tetraethoxysilane serves as a silicon source, P123 serves as a template agent, and a compound of n-decane and 1,3,5-trimethylbenzene serves as an additive; a hydrothermal synthesis method is utilized for preparing hollow spherical-segment-shaped mesoporous silica firstly, then the mesoporous silica serves as a fixed carrier for fixedly carrying chloroperoxidase. The preparation method is simple, reaction conditions are mild, the obtained mesoporous silica is in a hollow spherical segment shape, the specific surface area is large, the mesoporous diameter range is about 14-18 nm, unimolecular fixation of the chloroperoxidase can be realized, and certain turnover space is reserved for the chloroperoxidase. The hollow spherical-segment-shaped mesoporous silica / chloroperoxidase nanoreactor shows good degradation capacity on alizarin red, the degradation rate still can reach 100% after 8 times of use, the high temperature to which the nanoreactor is resistant is increased to about 50 DEG C, and the acid-base resistance is also improved.

The invention belongs to the field of food, in particular to the technical field of kimchi fermentation in food, and specifically relates to a low-salt kimchi microecological additive and a preparation method thereof. The low-salt kimchi micro-ecological additive includes the strain Lactobacillus pentosus, which is classified as Lactobacillus pentosus PCYSWX-5, and the strain was stored in the General Microorganism Center of China Microbiological Culture Collection Management Committee on July 15, 2016, and the preservation number is CGMCCNo.12793 . The micro-ecological additive prepared in the present invention can inhibit or kill common pathogenic bacteria such as Escherichia coli, Staphylococcus aureus, Enterobacter sakazakii, Listeria monocytogenes, Salmonella, and has no inhibitory effect on main fermentation bacteria , improve the safety of eating pickles; can strongly inhibit or kill the nitrate-reducing bacteria in low-salt pickles in the early stage of fermentation, so that the nitrite content in low-salt pickles is lower than the national standard.

The invention discloses a preparation method for a gamma-polyglutamate water absorption material. According to the method, gamma-polyglutamate adopted as a main raw material and caffeic acid-grafted chitosan oligosaccharide adopted as a biodegradable cross linking agent are used for preparing the gamma-polyglutamate hydrogel water absorption material in a water solution. The biodegradable cross linking agent is adopted to replace a common chemical crosslinking agent to prepare hydrogel, a reaction medium is not a toxic organic solvent any more, the safe and nontoxic gamma-polyglutamate is used as the main material, and the water-soluble degradable acrylic acid chitosan oligosaccharide is adopted as the cross linking agent to prepare the gamma-polyglutamate water absorption material. The real safe, nontoxic and biodegradable hydrogel is obtained as both the raw material and the medium are materials harmless to a human body, and the gamma-polyglutamate water absorption material is high in swelling ratio, excellent in mechanical property and improved in degradation property, and can be widely applied to disposable hygiene products, medicine carriers, medical supplies and the like.

The invention discloses a preparation method and application of a layered Steiner network structure fiber membrane. The fiber membrane is composed of polyvinyl alcohol, chitosan, polyvinylpyrrolidone, polyacrylic acid, polypropylene cellulose, polycarbonate , polyimide, the porogen is dichloromethane, polyvinyl alcohol, dimethyl sulfoxide, ammonium bicarbonate, sodium bicarbonate, acetone or tetrahydrofuran, the cross-linking agent is glutaraldehyde, methylenebisacrylamide , triethanolamine, polyethyleneimine or diethylenetriamine, the catalyst is made of hydrochloric acid, sulfuric acid or phosphoric acid and the solvent is deionized water, and the layered Steiner network structure fiber membrane prepared by this method is applied to the colorimetric explosive detection It can improve the sensitivity of colorimetric detection in terms of reaction time and response degree, and has the advantages of sensitive response, immediate display of results, simple operation and use, and the like. Moreover, according to the different explosive detection reagents loaded in the fiber membrane, it can detect and identify a variety of non-standard explosives and standard explosive raw materials, which is universal.

The invention discloses a method for preparing recombinant-penicillium amagasakiense glucose oxidase and application of the recombinant-penicillium amagasakiense glucose oxidase. Recombinant trichoderma reesei Tu6 delta tku70::Pgod constructed by introducing a Pgod gene into trichoderma reesei Tu6 delta tku70 can successfully express the recombinant-penicillium amagasakiense glucose oxidase, the expression quantity is high, and the enzyme activity in fermentation broth can achieve 28 U / mL. The recombinant-penicillium amagasakiense glucose oxidase in the fermentation broth is subjected to ni-sepharose purification, the enzyme activity in a protein solution obtained by ultrafiltration concentration can achieve 330 U / mL, and the specific activity of the recombinant-penicillium amagasakiense glucose oxidase is 407 U / mg protein. The recombinant-penicillium amagasakiense glucose oxidase prepared by the method has good heat stability and good acid-alkali tolerance, the fermentation process is simple, transferring is not needed, raw materials are cheap and are easily obtained, and the cost is greatly reduced. The recombinant-penicillium amagasakiense glucose oxidase can be widely applied to the fields of food and medicine.