78results about How to "Reduce feedback inhibition" patented technology

A microorganism strain suitable for fermentative production of L-methionine and preparable from a starting strain, which comprises increased activity of a yjeH gene product or of a gene product of a yjeH homolog, compared to the starting strain.

The invention discloses a device and method for realizing high-efficiency and low-consumption nitrogen and phosphorous removal of municipal sewage and belongs to the field of biological treatment of sewage and sludge. Sewage in a raw water tank sequentially enters an anaerobic zone and an aerobic zone of a reactor for enhanced biological phosphorus removal and whole-process nitrification through awater feeding pump; anaerobic phosphorus release is performed in the anaerobic zone; whole-process nitrification and aerobic phosphorus absorption effects are carried out in the aerobic zone; subsequently, the sewage is drained into a settling pond, supernate enters a reactor for fermentation coupling, short-cut denitrification and synchronous anaerobic ammonium oxidation of excess sludge. The excess sludge is quantitatively fed into the reactor for fermentation coupling, short-cut denitrification and synchronous anaerobic ammonium oxidation of the excess sludge each day; short-cut denitrifying bacteria transform nitric nitrogen into nitrite nitrogen by using organic matters produced by hydrolysis and fermentation of the sludge; anaerobic ammonium oxidizing bacteria transform excess ammonia nitrogen and nitric nitrogen into nitrogen. According to the device and the method disclosed by the invention, deep nitrogen and phosphorus removal of the municipal sewage is realized by using an enhanced biological phosphorus removal process, a short-cut denitrification process and an anaerobic ammonium oxidation process; moreover, sludge reduction is realized by the hydrolysis and fermentation effects of the sludge, so that energy conservation and consumption reduction are realized.

The invention provides a method for preparing absolute ethyl alcohol by furfural residues. A furfural residue cellulose raw material is adopted, lignin is separated, and then the absolute ethyl alcohol is obtained through synchronous diastatic fermentation and pervaporation coupling separation of alcohol, then distillation, pervaporation dehydration and rectification. The method has the advantages that the method organically combines the prior mature rectification technology with a modern advanced separation technology to improve the production efficiency when high fiber raw materials are used to prepare the absolute ethyl alcohol.

The invention discloses a construction method of a genetic engineering strain for producing shikimic acid. The method comprises the following steps of: 1, constructing an escherichia coli strain of which the aroA gene is knocked out; 2, constructing a recombinant expression plasmid pAR63 containing key enzyme genes aroGFBR, aroE, aroB, aroD, tktA and ppsA in the metabolic pathway of the shikimic acid, so that the genes are subjected to transcriptional control of a tryptophan promoter Ptrp; and 3, transferring the recombinant expression plasmid pAR63 into the escherichia coli strain of which the aroA gene is knocked out to obtain a production strain for expressing the shikimic acid. In the method, the aim of interrupting the metabolism of the shikimic acid is fulfilled by the knock-out of the single gene aroA, a small number of genes are knocked out, the operating difficulty is low, and the expression of the genes is in the state of starting and stopping automatically and is started automatically in the middle and late period without the induction of inducers, so the possibility of adding toxic substances into a culture medium is reduced, and the shikimic acid has high yield.

The invention provides a gene engineering bacterial strain for producing L-malic acid as well as a construction method and application thereof. In the invention, key phosphoenolpyruvate carboxykinase(PEPCK) related to the L-malic acid, malate dehydrogenase (MDH) and fumarase (FumC) are transformed to obtain the gene engineering bacterial strain; a deactivation mutation is carried out on the fumCto cause the interruption of a metabolic flux at the converting position from the malic acid to the fumaric acid so as to accumulate the target product L-malic acid; before the mdh, the promoter of aninner source pepck gene is added to generate the metabolic flux biased towards the malic acid; in addition, through the inducement of monofluorine sodium acetate, the activity of the PEPCK is improved, and the product feedback inhibition is greatly reduced. The bacterial strain applied to the fermentative production of the L-malic acid so as to obviously improve the yield of L-malic acid. The invention has advantages of simple technology, obvious effect and low cost and can satisfy the demand of markets.

The invention discloses a yeast engineering bacterium for producing d-limonene and a construction method thereof, belonging to the field of gene engineering. In the invention, limonene synthetase from Citrusunshiu is heterologously expressed in Saccharomyces cerevisiae CEN.PK2-1C by metabolic engineering modification to increase ways (mevalonic acid (MVA) carbon metabolic flux) for synthesizing terpenoids, thereby obtaining a yeast engineering bacterium strain CEN.PK2 limonene for producing d-limonene at high yield. Compared with the original strain CEN.PK2-1C, the modified yeast engineering bacterium can produce d-limonene by metabolism, the feedback inhibition on d-limonene is obviously lowered, and the yield of d-limonene can reach 13 mg/L, thus the invention has wide application prospects.

The present invention discloses a method for raising secondary metallic product output of myxobacteria, i,e, a method for raising output of metabolic product epothilone A of sorangium cellulosum of ephothilone in myxobacteria, and the said method incldues: 1). naturalization method of lump-grown myxobacterial liquid uniform growth; (2). selecting potato starch and hydrolyzed lactoprotein, etc. suitable for production of epothilone A; and 3). addition method of mixed resin for integrally-eliminating product metabolic accumulation so as to make the output of ephothiloue A product be up to 62.7 mg/L level.

The invention discloses construction and application of a saccharomyces cerevisiae strain for extracellular transport of vitamin D3 precursor squalene, and belongs to the technical field of fermentation engineering. The construction comprises the following steps of: firstly, constructing a recombinant saccharomyces cerevisiae strain Z1O3 for high yield of squalene, wherein the recombinant saccharomyces cerevisiae intensively expresses 3-hydroxy-3-methylglutaryl coenzyme A reductase, isopentenyl pyrophosphate isomerase, farnesyl pyrophosphate synthase, and related genes INO2, Pdr5 protein and Osh3 protein of endoplasmic reticulum size regulating factors; knocking out ROX1 gene; when the strain is subjected to shake flask fermentation, the content of squalene in extracellular dodecane of the strain reaches 893.58mg/L; and when the strain is cultured in a fermentation tank, the content of squalene in extracellular dodecane of the strain can reach 6995.81mg/L. The recombinant strain constructed by the invention not only has the ability of extracellular transport of squalene, but also has stronger squalene production performance, and has broad application prospects.

The invention utilizes a flat plate photobioreactor integrating a fuel battery to integrate microalgae high-density culture and irradiation hydrogen production so as to form an integrative hydrogen production system. Two sections of processes of microalgae culture and photosynthetic hydrogen production are generally divided in space time, and the cultured low-density frustule needs to be concentrated and then irradiated to produce hydrogen, so that the operations need to be respectively carried out in two photobioreactors. In the microalgae hydrogen production of the invention, the low-density microalgae is inoculated into a reactor, a culture mode of enriching carbon dioxide is utilized, the biomass required by the hydrogen production can be reached by short-term culture, then dark induction is carried out, and the operation can enter a continuous irradiation hydrogen production stage. The generated hydrogen gas can be integrated into a fuel battery on a reactor and is converted into electric energy, and the hydrogen production condition can be monitored at real time by the change of current. The invention combines the two sections of processes of the microalgae culture and the hydrogen production for the first time, utilizes the fuel battery to convert the hydrogen into the electric energy and provides reliable technical support for the large-scale microalgae hydrogen production.

A process and equipment for preparing alcohol by the coupled solid-phase cellulose enzymolysis and liquid fermentation are disclosed. Its equipment is composed of vertical reactor consisting of internal and external cylinder, upper and lower closure heads, upper and lower plate filters, air-floating valve connected to lower part of internal cylinder, CO2 gas circulating pump, and enzymolyzed liquid circulating pump. Said process includes adding cellulose and cellulose into the cavity between internal and external cylinders, leaching the enzymolyzed substance of cellulose, pumping the liquid into internal cylinder, adding yeast into internal cylinder, fermenting, and separating and recovering alcohol.

The invention provides a glutathione synthetase-based recombinant plasmid, a construction method and application thereof, and a method for accumulating glutathione. The glutathione synthetase-based recombinant plasmid provided by the invention includes sequences GSH1 and GSH2 as well as two appropriate vector segments; the principle of the method lies in that as GSH1 and GSH2 are connected onto vectors with different promoters, step-by-step expression of GSH1 and GSH2 can be realized through adding inducers at different time to reduce feedback inhibition; with the adoption of the method provided by the invention, the feedback inhibition can be weakened remarkably, the yield of glutathione is improved, the utilization ratio of raw materials is improved, and a base model is established for further studying synthesis of glutathione by a biological method. In addition, the method and the idea can be applied to target products of which the yield improvement is restricted due to the feedback inhibition, and provide a new idea for producing valuable products.

The invention discloses a method for building engineering strains of producing tryptophan and relates to the method for building gene engineering strains of producing tryptophan. The problem to be solved is that the method for producing tryptophan at present is low in yield of tryptophan and high in cost. The method comprises the steps of: carrying out PCR (polymerase chain reaction) augmentation by taking escherichia coli JM109 genome DNA as a template to obtain target genes aroG and trpBA; building pMD18-T-aroG, connecting with a pET-32a vector after enzyme digestion to obtain a connection product X; building pMD18-T-trpBA, connecting with a pET-30a vector after enzyme digestion, thus obtaining a connection product Y; converting the connection product X into a competent cell, and converting the connection product Y into a positive recombinant strain namely an engineering strain of producing tryptophan. The engineering strain built by the method can excessively express DAHP (EC 2.5.1.54,3-deoxy-D-arabino-heptulosonate-7-phosphate synthase) synthetase and tryptophan synthetase, reduce feedback inhibition of a reaction product on the tryptophan synthetase, and increase the yield of the tryptophan. The method is used for producing the tryptophan.

The invention discloses a method for producing ethanol by carrying out high temperature enzymolysis and fermentation on lignocellulose. The method for producing the ethanol by carrying out the high temperature enzymolysis and fermentation on the lignocellulose comprises the following steps: (1) pretreating a lignocellulose raw material, so as to obtain a pretreated raw material; (2) adding the pretreated raw material, cellulase, water and xanthan gum into an enzymatic vessel for carrying out pre-enzymolysis, and controlling dry material concentration of an enzymolysis system to be 15-25wt%; (3) pumping an enzymolyzed feed liquid into a fermentation tank, adding temperature-resistant saccharomyces cerevisiae, and carrying out simultaneous saccharification and fermentation; and (4) pumping fermentation liquor into a rectification device and separating ethanol. The method disclosed by the invention has the advantages that the xanthan gum is added into the enzymolysis system, high temperature tolerance of cellulase is improved, activity of the cellulase under high temperature enzymolysis condition is high, usage amount of the cellulase is reduced, enzymolysis efficiency of the lignocellulose is improved, and economy is improved.

The invention relates to a double column production method of gamma-aminobutyric acid by immobilized cell and D101 resin, which belongs to the technical field of green biological production; according to the double column production method, a D101 macroporous adsorption resin column is taken as an auxiliary reaction column and is coupled mutually with an immobilized enterococcus faecium cell reaction column, and the coupled macroporous adsorption resin column and the immobilized enterococcus faecium cell reaction column are connected with other auxiliary installation or equipment to form a cyclic reaction system, efficient conversion is realized as a reaction substrate is cycled between the D101 macroporous adsorption resin column and the immobilized enterococcus faecium cell reaction column, and productivity of the gamma-aminobutyric acid is improved; compared with a catalytic reaction method only using the immobilized enterococcus faecium cell reaction column, the output of the gamma-propalanine produced by the invention can be increased by 196.32%. Besides, purification of the gamma-aminobutyric acid also can be realized through the adsorption effect of the D101 resin column, a downstream process is simplified, the cost is reduced, and is environmentally friendly.

The invention relates to a prokaryotic microorganism strain capable of overproducing γ-glutamylcysteine and its derivatives bis-γ-glutamylcystine and γ-glutamylcystine, which can be prepared from a parent strain, wherein said strain has a reduced cellular glutathione synthetase activity compared to the parent strain, and has a cellular γ-glutamylcysteine synthetase activity which is more greatly increased than in a strain with similarly reduced cellular glutathione synthetase activity.

A microorganism strain suitable for fermentative production of amino acids of the phosphoglycerate family or derivatives thereof and producible from a starting strain, is based upon a starting strain having an increased activity of a yfiK-gene product or of a gene product of a yfiK homologue. The microorganism strain is a member of the family Enterobacteriaceae and is a member of the species E. coli. A plasmid has a Yfik-gene with a promoter and a genetic element for the deregulation of cysteine metabolism coding for a serine O-acetyl transferase and being subject tot a reduced feedback inhibition by L-cysteine.

The invention relates to a method for increasing the activity of enterococcus faecium Glutamate Decarboxylase by using D101 macroporous adsorption resin, and belongs to the technical field of biology. According to the method disclosed by the invention, the D101 microporous adsorption resin is used as an enzyme activity accelerator of enterococcus faecium GAD, and a D101 microporous adsorption resin-GAD composite catalytic system is constructed according to a proportion that the mass of the D101 macroporous adsorption resin to the volume of a substrate solution to the volume of an enterococcus faecium bacterial suspension solution or a GAD free enzyme solution is 1 to 1 to 1; when the D101 microporous adsorption resin-GAD composite catalytic system is subjected to reaction in a water bath oscillator of which the temperature is 37 to 43 DEG C at 80r/min or stirring reaction in a stirring tank at a low speed for 24 to 36 hours, the yield of GABA (Gamma-Aminobutyric Acid) can be increased by 18.54 to 149.11 percent; the D101 macroporous adsorption resin is capable of remarkably increasing the activity of the GAD, an exchange adsorption function of the D101 microporous adsorption resin on the GABA is also a purifying process of the GABA, a downstream extracting and purifying technology is simplified, and the production cost is reduced; the method is simple, green and environment-friendly.