14 results about "Oxaloacetic acid" patented technology

The invention provides a genetic engineering strain for efficiently producing beta-alanine, an escherichia coli strain is modified by adopting a genetic engineering means, and a multi-plasmid system is constructed, so that a metabolic pathway is optimized and the product synthesis efficiency is improved. The method comprises the following steps: firstly, by constructing a recombinant plasmid pET-PanD, introducing aspartic acid decarboxylase (L17F / G24R mutant) with mutation so as to promote efficient conversion of aspartic acid to beta-alanine; meanwhile, phosphoenolpyruvate carboxylase (PPC) is overexpressed through the recombinant plasmid pRSF-PPC, generation of oxaloacetic acid (OAA) is increased, and then the synthesis path of carbon flow to beta-alanine is improved. Besides, NADH dependent type aspartate dehydrogenase (AspDH) from pseudomonas aeruginosa is overexpressed by adopting a pBAD-AspDH plasmid, so that the dependence on NADPH is reduced, and the conversion efficiency is further improved.

The invention belongs to the technical field of leaf surface resistance and control agents, and particularly relates to a leaf surface resistance and control agent for reducing the content of cadmium and lead in rice and a preparation method thereof. The invention relates to a leaf surface blocking and controlling agent, which is prepared by mixing the following components in percentage by mass: 3 to 15 percent of active component, 6 to 15 percent of dispersing agent and the balance of inorganic salt, the active component is formed by compounding ethylenediaminetetraacetic acid, oxaloacetic acid and silicon dioxide sol. The foliar blocking and controlling agent disclosed by the invention takes ethylenediaminetetraacetic acid, oxaloacetic acid and silicon dioxide as active ingredients, so that accumulation of heavy metals cadmium and lead in rice can be remarkably reduced, further the content of cadmium and lead in rice can be effectively reduced, and a support is provided for safe production of rice. Besides, positive ions in inorganic salts such as zinc sulfate, manganese sulfate and ferrous sulfate can antagonize transfer of cadmium and lead in rice plants to the rice, so that accumulation of heavy metal cadmium and lead in the rice is reduced, elements such as zinc, manganese and iron required by growth of the rice can be supplemented, and growth of the rice plants is promoted.

The invention belongs to the technical field of leaf surface resistance and control agents, and particularly relates to a leaf surface resistance and control agent for reducing the cadmium content of rice and a preparation method thereof. The leaf surface blocking and controlling agent for reducing the cadmium content of the rice is formed by compounding active ingredients of oligosaccharide and oxaloacetic acid, and the mass ratio of the oligosaccharide to the oxaloacetic acid is (1-100): (100-1). Chitosan oligosaccharide and oxaloacetic acid are mixed to serve as an active component of the leaf surface blocking and controlling agent, and rice tests find that when the active component is sprayed on leaf surfaces of rice in the booting stage and the filling stage respectively, transportation and accumulation of heavy metal cadmium in soil in the rice can be effectively prevented and controlled, and then the content of the heavy metal cadmium in the rice can be reduced; and support can be provided for green and safe production of rice. In addition, positive ions in inorganic salts such as zinc sulfate, manganese sulfate and ferrous sulfate can antagonize transfer of cadmium and lead in rice plants to the rice, so that accumulation of heavy metal cadmium and lead in the rice is reduced, elements such as zinc, manganese and iron required by growth of the rice can be supplemented, and growth of the rice plants is promoted.

This invention discloses a culture medium and process for alleviating ammonium accumulation in cells. The concentrations of the substances added to the culture medium are as follows: 2 g / L glutamate, 0 g / L glutamine, 2 g / L aspartic acid, 2 g / L asparagine, 1 g / L serine, 1 g / L pyruvate, 0.5 g / L α-ketoglutarate, 0.5 g / L oxaloacetic acid, 0.5 g / L proline, 0 g / L glucose, 8 g / L galactose, and 0.1% glycerol. Compared with the prior art, the advantages of this application are: this method mainly achieves the purpose of maintaining cell viability and reducing the cell metabolic byproduct ammonium ions by adjusting the proportion of substances related to cell metabolic pathways and adding additional cell protectants; using the optimized culture medium of this invention, the cell viability can be increased from 42.38% to 95.21% and the ammonium ion concentration can be reduced from 6.308 mM to 0.914 mM by day 7.

The invention discloses a construction method and application of an engineering bacterium for increasing the yield of alpha-ketoglutaric acid. Wild E.coli.W3110 serves as a chassis strain, lactic dehydrogenase ldhA, pyruvate dehydrogenase poxB and formic acid C-acetyltransferase pflB are knocked out firstly, and the flow direction of pyruvic acid to lactic acid, acetic acid and formic acid is blocked; meanwhile, the promoter PBBaJ23109 is used for replacing a natural promoter of the sucA gene, so that alpha-ketoglutaric acid dehydrogenase is weakened, and the decomposition way of alpha-ketoglutaric acid is weakened; the phosphoenolpyruvate carboxylase ppc is overexpressed, and the flow direction of phosphoenolpyruvate to oxaloacetic acid is enhanced; isocitrate dehydrogenase icd from escherichia coli is overexpressed, so that synthesis of a product is promoted; besides, pyruvate dehydrogenase derived from saccharomyces cerevisiae is introduced and coded by genes PDB1, PDA1 and LAT1, so that an important precursor, namely pyruvic acid, is promoted to flow to acetyl coenzyme A; the engineering strain with high yield of alpha-ketoglutaric acid is finally obtained, the yield of 75.1 g / L can be achieved in a 5L fermentation tank through a fed-batch fermentation method for 40 hours, and the conversion rate is 39.6%.

The application provides a CO2 capture method and a CO2 capture device coupled with electrochemical regeneration of hydrogen. The method comprises the following steps: absorbing CO2 in a CO2-containing gas by using an alkaline solution to form a CO2-rich solution; performing acid-base neutralization of the CO2-rich solution and an acidic solution to obtain a neutralization solution and CO2; performing electrolysis of the neutralization solution to obtain a cathode electrolysis product and an anode electrolysis product, wherein the cathode electrolysis product is H2 and the alkaline solution, and the anode electrolysis product is O2 and the acidic solution; and the acidic solution is selected from one or a combination of more than two of the following solutions: pyruvic acid solution, gluconic acid solution, malonic acid solution, tartaric acid solution, glyceric acid solution, oxalacetic acid solution, formic acid solution, isopropionic acid solution, isobutyric acid solution, fumaric acid solution, aconitic acid solution, isocitric acid solution and hexanediol diacid solution. The acidic solution generated by electrolysis can avoid corrosion of the device equipment and reduce the net energy consumption and net cost of the CO2 capture process.

The application discloses a high-yield beta-alanine engineering bacterium and method based on a type I CRISPRi screening system, wherein by knocking out a pckA gene encoding oxaloacetate to phosphoenolpyruvate and a nadB gene encoding L-aspartate to oxaloacetate, a countercurrent pathway for synthesizing beta-alanine is blocked, and carbon flow loss is reduced; by knocking out an ldhA gene and a poxB gene, the content of synthesized pyruvate is increased; by overexpressing an NCgl0580 gene, the tolerance of EcN to products is improved; by knocking out a lacI gene in a genome, the adding cost of an inducing agent in a fermentation process is reduced; by optimizing a type I CRISPRi system for high-throughput screening of target genes affecting the yield of beta-alanine in the engineering bacterium, the screening efficiency and accuracy are significantly improved, an aspartate tRNA ligase gene aspS capable of improving the yield of beta-alanine is obtained, by overexpressing the aspS, the PanD enzyme activity is increased, and the yield of beta-alanine is further improved.

The invention provides a synthesis method of 4, 7-dichloroquinoline, and relates to the technical field of compound preparation. Comprising the following steps: synthesizing 7-chloro-4-hydroxyquinoline-2-carboxylic acid by a one-pot method, and then carrying out decarboxylation and chlorination on the 7-chloro-4-hydroxyquinoline-2-carboxylic acid to obtain the 4, 7-dichloroquinoline. Wherein the step of synthesizing the 7-chloro-4-hydroxyquinoline-2-carboxylic acid by the one-pot method comprises the following steps: condensing m-chloroaniline and diethyl oxaloacetate to obtain a compound shown as a formula 3, directly adding condensation reaction liquid into an organic solvent, and heating and cyclizing to obtain 7-chloro-4-hydroxyquinoline-2-carboxylic acid ethyl ester; after the cyclization reaction is completed, sodium hydroxide is added for hydrolysis, and 7-chloro-4-hydroxyquinoline-2-carboxylic acid is obtained. The method has the advantages of simple operation, high productivity, safety, environmental protection, easily available raw materials, and suitableness for industrial production.

Described herein is a novel enzymatic pathway and acid tolerant Schizosaccharomyces pombe strain exhibiting the same, for producing 3-hydroxypropionic acid by fermentation wherein the S. pombe strain includes nucleotide sequences that encode, and which are operably linked to promoters to express, non-native enzymes that exhibit an oxaloacetate decarboxylase (ODC) activity that converts oxaloacetate to 3-oxopropionate and a 3-oxopropionate reductase (OPR) activity that converts the 3-opropionate to 3-hydroxypropianate. ODC and OPR enzymes are not known to exist in nature, nor is an enzymatic path for making 3-hydroxypropionic acid but particular enzymes exhibiting the requisite activities are herein identified by sequence. A further enhancement is to also overexpress an enzyme that has at least one of a pyruvate carboxylase activity, a phosphoenolpyruvate carboxy kinase activity, and a phosphoenolpyruvate carboxylase activity, which increases the level of oxaloacetate in the cell leading to greater 3-HP production.

The application relates to a phosphorus-free neutral rust remover and a preparation method, and relates to the technical field of rust removal.The phosphorus-free neutral rust remover comprises the following components in proportion by weight: 5-10 parts of sodium hydrosulfite, 5-10 parts of phosphorus-free washing agent, 0.5-2 parts of dispersant, 10-20 parts of phosphorus-free chelating agent and 67-84 parts of water; the phosphorus-free washing agent is obtained by compounding oxalacetic acid and polyether compounds.The specific phosphorus-free washing agent obtained by compounding oxalacetic acid and polyether compounds, the specific reducing agent of sodium hydrosulfite, the phosphorus-free chelating agent and the dispersant are compounded to prepare the phosphorus-free neutral rust remover.The phosphorus-free neutral rust remover can selectively and efficiently remove iron rust on the surface of stainless steel and will not damage the metal base, and the problems of low safety, poor rust removal effect and corrosion of the metal base of the existing rust remover are solved.

The present invention is directed to methods of controlling the growth of undesired vegetation in a particular area by using an herbicidal composition that contains an esterified plant metabolite.

To remove senescent cells, and / or to prevent, suppress, or improve skin aging phenomena such as age spots, wrinkles, sagging, dullness, thinning of the skin, weakening of the skin, decreased skin barrier function, and dryness by removing senescent cells. [Solution] A composition containing lactic acid, indole lactic acid, phenyl lactic acid, catechin, caffeic acid, umbelliferone, parthenolide, pyridoxine hydrochloride, arbutin, hinokitiol, oxaloacetate, tocotrienol, tocopherol, γ-oryzanol, retinol acetate, retinyl palmitate, riboflavin, and pantothenyl ethyl ether, as well as chemically possible salts thereof, and at least one selected from the group consisting of Enterococcus bacteria and Lactobacillus bacteria.

This invention discloses an aspartate dehydrogenase mutant and its applications. The aspartate dehydrogenase can catalyze the production of aspartic acid from oxaloacetate, but its catalytic ability is low, with a molar conversion rate of only about 8.4% for the product aspartic acid. The mutant exhibits mutations at positions 155, 182, 273, and 355 of the original aspartate dehydrogenase amino acid sequence: proline at position 155 is mutated to serine, phenylalanine at position 182 is mutated to leucine, aspartate at position 273 is mutated to glycine, and valine at position 355 is mutated to glycine. The aspartate dehydrogenase mutant significantly increases the amount of aspartic acid produced from oxaloacetate, achieving a molar conversion rate of up to 95.2%, thus demonstrating high potential for industrial application.