95 results about "Homoserine" patented technology

The invention provides a genetically engineered bacterium for producing O-succinyl-L-homoserine as well as a construction method and application of the genetically engineered bacterium. In a chassis bacterium genome, the expression of a 2-ketoglutaric acid decarboxylase encoding gene sucA is enhanced, and the expression of a succinyl-coenzyme A synthetase encoding gene sucD is weakened, so that the supply of succinyl-coenzyme A is increased; the method comprises the following steps: increasing the NADPH (Nicotinamide Adenine Dinucleotide Phosphate) reducing capacity and ATP (Adenosine Triphosphate) energy supply of a chassis bacterium, increasing DNA (Deoxyribose Nucleic Acid) in combination with a transcription dual regulatory factor ompR to improve the stress resistance of escherichia coli under high osmotic pressure, and introducing an overexpression plasmid containing a homoserine transsuccinylase coding gene metA to construct the genetically engineered bacterium for producing O-succinyl-L-homoserine. The engineering strain obtained through a systematic metabolic engineering modification strategy can realize effective accumulation of OSH, the shake flask yield of OSH reaches 19.8 g / L, the fed-batch fermentation yield of a 5L fermentation tank reaches 110.5 g / L, the sugar-acid conversion rate reaches 52.6%, and a foundation is laid for subsequent construction of high-yield OSH engineering bacteria.

The invention belongs to the technical field of synthetic biology, and particularly relates to recombinant escherichia coli for efficiently producing O-acetyl-L-homoserine as well as a construction method and application of the recombinant escherichia coli. According to the invention, CRISPR-Cas9 gene editing is combined with metabolic modification, so as to precisely integrate OAH biosynthesis key nodes: introducing and overexpressing a mutant metX gene at a genome pseudogene site to enhance the expression of homoserine acetyltransferase, knocking out byproducts such as poxB and mgsA to synthesize genes, and carrying out high-yield synthesis of OAH. Corynebacterium glutamicum thrA (anti-feedback inhibition), aspB and bacillus subtilis acsA-acuA genes (construction of an acetic acid switch) are introduced, gene expression of gltA, tpiA and the like is optimized to increase supply of precursors such as acetyl CoA and the like, and finally a stable strain without plasmids, antibiotics and inducers is obtained. The production cost is effectively reduced, and the method has the advantage of high genetic stability and shows a good application prospect in OAH industrial production.

The invention discloses a phycomycete symbiotic system and application of the phycomycete symbiotic system in treatment of aquaculture tail water, and belongs to the technical field of tail water treatment. The phycomycete symbiotic system comprises chlorella, scenedesmus and activated sludge, and the initial inoculation dry weight ratio of the chlorella to the scenedesmus to the activated sludge is 1: 1: 6. And exogenously adding octanoyl-L-homoserine lactone or tetradecanoyl-L-homoserine lactone into the phycomycetes symbiotic system, so as to construct the phycomycetes symbiotic system with enhanced functions. On the basis of a mixed algae-bacteria symbiotic system with an optimized ratio, directional enhancement of functions is realized by virtue of quorum sensing signal molecules, the stability and resistance gene interception capability of the quorum sensing signal molecules under the stress of antibiotics are verified, and finally efficient purification of the aquaculture tail water is realized. According to the invention, the blank of the prior art in the aspects of advanced regulation and control of a phycomycete synergistic mechanism and synergistic treatment of emerging pollutants is filled up.

Escherichia coli is modified by means of metabolic engineering, a genetically engineered bacterium for high yield of O-succinyl-L-homoserine is obtained, and a construction method of the genetically engineered bacterium comprises the following steps: weakening a synthetic route of an organic acid metabolic byproduct of a chassis strain E.coli W3110 [delta] metI [delta] metJ [delta] thrB [delta] metB; wherein the synthetic route of the organic acid metabolic byproducts is selected from at least one of a formic acid synthetic route, a lactic acid synthetic route and an ethanol synthetic route. The constructed genetically engineered bacterium is applied to microbial fermentation production of the O-succinyl-L-homoserine, effective accumulation of the O-succinyl-L-homoserine is achieved, the sugar acid conversion rate reaches 46.8%, and a foundation is laid for subsequent construction of high-yield O-succinyl-L-homoserine engineering bacteria.

The invention provides a recombinant O-succinyl-L-homoserine mercaptotransferase mutant, a coding gene thereof, a recombinant vector containing the coding gene of the mutant, a recombinant genetically engineered bacterium obtained by converting the recombinant vector, and application of the recombinant O-succinyl-L-homoserine mercaptotransferase mutant in preparation of L-methionine. The novel recombinant O-succinyl-L-homoserine mercaptotransferase mutant with high activity and high selectivity is used as a catalyst to be applied to catalysis of O-succinyl-L-homoserine for synthesis and preparation of L-methionine, a catalytic reaction system is optimized, the feed ratio and reaction conditions in the reaction are finely regulated and controlled, and the yield of L-methionine is increased. The recombinant O-succinyl-L-homoserine mercaptotransferase mutant has high enzyme activity under the optimal reaction condition, the catalytic efficiency is further improved, the purposes of reducing cost and improving efficiency are achieved, and the method has important significance in promoting industrial application of biological catalysis preparation of L-methionine.

The present disclosure provides a recombinant Escherichia coli strain modified by metabolic engineering means and a method for producing L-homoserine by using the same. The strain, designated as Escherichia coli having a strain number of 13-XA, is deposited in China General Microbiological Culture Collection Center (CGMCC) with an accession number of CGMCC No. 25099, dated Jun. 16, 2022. With respect to the chromosome DNA thereof, one or more genes associated with fatty acid metabolism are knocked out or attenuated, and / or a promoter is replaced for enhancement; one or more genes associated with the L-homoserine metabolic pathway are knocked out or attenuated, and / or one or more genes associated with the L-homoserine metabolic pathway are overexpressed or enhanced, and / or one or more genes associated with the L-homoserine metabolic pathway are mutated.

The present invention relates to an enzymatically catalyzed method for producing L-glufosinate or a phosphoester thereof. The method includes reacting an activated L-homoserine HA with a substrate S selected from methylphosphinic acid and esters thereof. Sulfhydrylase enzyme E1 is used for the enzymatic catalysis. The invention makes accessible new substrates for the enzymatic production of L-glufosinate and its phosphoesters.

The invention belongs to the technical field of biology, and discloses a biosynthesis method of L-homoserine. According to the biosynthesis method, L-homoserine is synthesized by taking L-aspartic acid and formaldehyde as substrates, aldolase and transaminase are adopted, and oxaloacetic acid decarboxylase can be optionally added to improve the efficiency of a catalytic system. The method can be realized through an in-vitro multi-enzyme catalysis system, and can also be completed in a manner of introducing a way into microorganisms. According to the method, methanol, formaldehyde and other carbon resources can be introduced to synthesize the L-homoserine with high value, the raw materials are low in price, and the whole synthesis method has the advantages of high atom utilization rate and high conversion rate.

This invention discloses the application of homoserine as a barrier repair factor in the preparation of skin repair compositions. As a multidimensional regulator of skin barrier function, homoserine systemically integrates post-sun exposure damage repair, physical barrier repair, and microecological barrier repair, providing a multi-target synergistic mechanism to effectively repair the skin barrier and alleviate skin damage. The application of homoserine in cosmetics or skin care products meets consumers' needs for precise skin repair.

The invention discloses a method for synthesizing L-glufosinate-ammonium by using whole cells as a catalyst. The method comprises the following step: carrying out cell catalytic reaction in a water phase system containing microbial cells, L-homoserine and / or activated L-homoserine and a phosphorus donor compound to prepare the L-glufosinate-ammonium. According to the present invention, the microbial cells are adopted as the catalyst, the L-homoserine and / or the activation form thereof are / is adopted as the raw material to directly synthesize the L-glufosinate-ammonium in the pure water system, and the method has advantages of high selectivity, high catalysis efficiency, good stability, cell recycling and the like.

O-acyl homoserine hydrosulphide variants and uses thereof are provided.

The invention provides a method for producing L-carnosine, a genetic engineering strain as well as a preparation method and application of the genetic engineering strain, and belongs to the field of genetic engineering. According to the genetic engineering strain provided by the invention, by knocking out a glucose-6-phosphate isomerase coding gene pgi, knocking out an L-threonine / L-homoserine transporter coding gene rhtA or knocking out a dipeptide transfer protein coding gene dppABCD, the yield of extracellular L-carnosine is increased, the shake flask yield of the finally constructed strain reaches 9.1 g / L, the 5L fermentation tank yield reaches 65 g / L, and the yield of the extracellular L-carnosine reaches 9.1 g / L; and the method has a good application prospect in L-carnosine biosynthesis.

The invention relates to the technical field of microorganisms, and particularly discloses a construction method and application of a recombinant microorganism. According to the construction method of the recombinant microorganism, compared with an original strain, the expression quantity of threonine operon leader peptide of the recombinant microorganism is reduced, and the expression quantities of glyceraldehyde-3-phosphate dehydrogenase mutant, aspartate kinase / homoserine dehydrogenase I mutant, homoserine kinase and threonine synthase are increased; the glyceraldehyde-3-phosphate dehydrogenase mutant is characterized in that glycine at the 188th site in a glyceraldehyde-3-phosphate dehydrogenase protein sequence is mutated into serine; the aspartate kinase / homoserine dehydrogenase I mutant is characterized in that glycine at the 433rd site in an aspartate kinase / homoserine dehydrogenase I protein sequence is mutated into arginine; the starting strain is escherichia coli. According to the construction method disclosed by the invention, a novel recombinant microorganism with improved threonine yield can be obtained, and a novel method is provided for fermentation production of threonine.

This invention discloses the application of homoserine as an aging regulator in the preparation of anti-aging skin compositions. As a multidimensional regulator of skin aging, homoserine integrates skin cell lifespan regulation, telomere protection, and oxidative protection, providing a multi-target synergistic mechanism that can comprehensively and effectively delay skin aging, reduce wrinkles and sagging, and enhance vitality. The application of homoserine in cosmetics or skin care products meets consumers' demand for precise anti-aging skincare.

The application discloses a kind of high-yield O-succinyl-L-homoserine recombinant escherichia coli and its construction method and application, belong to genetic engineering and fermentation engineering technical field.The recombinant escherichia coli is expressed by expressing anti-feedback inhibition homoserine O-succinyltransferase metA fbr , aspartate ammonia-lyase aspA, aspartate transaminase aspC, 2 ketoglutarate decarboxylase sucA, dihydrothioctic acid succinyltransferase sucB and efflux protein yjeH, knock out metJ, improve intracellular NADPH availability, to enhance OSH synthesis pathway metabolic flow, precursor succinyl coenzyme A supply and product efflux.Using 5 L bioreactor for fed-batch fermentation, after fermentation 60 h, OSH production is as high as 137.4 g / L, and sugar acid conversion rate reaches 50.5%.The application provides engineering strain and technical realization path for the efficient fermentation of OSH.

This invention provides a compound drug for treating melioidosis, its preparation method, and its application. The drug comprises active components of traditional Chinese medicine, a bioactive preparation, and a pharmaceutically acceptable carrier. The active components of traditional Chinese medicine are primarily extracts of Scutellaria baicalensis, Coptis chinensis, Fagopyrum dibotrys, and Polygonum cuspidatum. The bioactive preparation includes polymyxin B, homoserine lactonease, and recombinant human β-defensin 3. The components work synergistically to construct a comprehensive intervention system covering all pathological stages, including biofilm disruption, sterilization, anti-endotoxin activity, intracellular bacterial clearance, immune regulation, and tissue repair. This system can effectively disrupt bacterial biofilms, kill multidrug-resistant strains, neutralize endotoxins, and eliminate latent intracellular bacteria, addressing the core pain points of existing melioidosis treatments, such as strong drug resistance, significant toxic side effects, and high recurrence rates. The preparation process of this invention is carried out under low-temperature and sterile conditions throughout, which fully preserves the stability of the active ingredients, making it suitable for industrial production. The drug can be prepared in various dosage forms, covering all clinical subtypes of melioidosis, and possesses clinical application value and promising prospects for widespread application.

The present application belongs to the technical field of quorum quenching enzyme preparation, and particularly relates to a multi-target quorum quenching enzyme preparation and a preparation method and application thereof, such as being mainly used for inhibiting the virulence factors of Pseudomonas aeruginosa, and including acyl homoserine lactone acyltransferase AiiO protein and 3-hydroxy-4-oxoquinolone 2,4-dioxygenase AqdC protein, and the mass ratio of the two is 20:(1-25); such as being mainly used for inhibiting the virulence factors and the synthesis of biological membranes of Pseudomonas aeruginosa, and further including deferiprone, and the mass ratio of AiiO, AqdC and deferiprone is 20:(1-25):(0.695-2.78), the present application can target the Las, Rhl and PQS of Pseudomonas aeruginosa, the yield and stability of the prepared AqdC protein are both high, the two types of enzymes are used in combination after the regulation amount, and the virulence factors regulated by different quorum sensing pathways in Pseudomonas aeruginosa are effectively inhibited; the regulation amount of deferiprone is used in combination with the two types of quorum quenching enzymes, and the virulence and biological membranes of Pseudomonas aeruginosa can be effectively inhibited in a comprehensive manner.

The invention discloses a recombinant O-acetyl-L-homoserine mercaptotransferase mutant, a recombinant genetically engineered bacterium and application of the recombinant O-acetyl-L-homoserine mercaptotransferase mutant and the recombinant genetically engineered bacterium. The mutant is obtained by performing single mutation or multiple mutation on the 33rd site, the 55th site, the 237th site and the 238th site of an amino acid sequence shown in SEQ ID NO.2. The method has the beneficial effects that the method has more efficient catalytic activity and stronger substrate tolerance, has the advantages of mild conditions, less discharge of three wastes, high selectivity and high product yield when being used for catalyzing OAH and sodium methyl mercaptide to synthesize L-methionine, and has a wide development space in the aspect of industrial production of L-methionine.

This invention provides an engineered bacterium for producing ectoine, its preparation method, and its application. The engineered bacterium is prepared using a method comprising the following steps: using *Corynebacterium glutamicum* as the starting strain, feedback inhibition by aspartate kinase LysC is relieved, the activity of the gene lysE encoding lysine efflux permease is reduced, and the ectoine synthesis gene cluster ectABC is expressed. Based on this, the activity of any one or at least two of the following—diaminobutyrate acetyltransferase EctA, pyruvate carboxylase Pyc, or aspartate kinase LysC—is enhanced, and / or the activity of any one or at least two of the following—maloquinone oxidoreductase Mqo or homoserine dehydrogenase Hom—is reduced to further increase ectoine yield.

The present disclosure relates to a method for preparing O-acetyl-homoserine, which comprises a main culture step of culturing an O-acetyl-homoserine producing strain in a medium to produce O-acetyl-homoserine, and in which a potassium salt is supplied to the medium. According to the present disclosure, O-acetyl-homoserine productivity (g / L / hr) is improved by additionally supplying potassium ions in the form of a potassium salt to the main medium in the culture method for producing O-acetyl-homoserine.

The application belongs to the technical field of pesticide synthesis method, and relates to a preparation method of L-chlorohomoserine ethyl (methyl) ester or a salt thereof. Specifically, the application discloses a preparation method of a compound of formula I or a salt thereof, which takes a compound of formula A or a salt thereof as raw material, and reacts with a compound of formula B in an organic solvent in the presence of a solid acid catalyst to obtain L-chlorohomoserine ethyl (methyl) ester or a salt thereof. The method is simple in process, simple in post-treatment and purification process, the catalyst can be recycled by filtration, the reaction solvent containing no water can be directly recycled and reused, the product is high in purity and yield, the method is environment-friendly, and is suitable for industrial production.

The invention provides an engineering bacterium for producing spermidine and a preparation method of the engineering bacterium, and relates to the field of genetic engineering. According to the invention, arginine decarboxylase, aspartate kinase, aspartate-semialdehyde dehydrogenase, spermidine efflux protein (MdtI / MdtJ), carboxylaminopropyl agmatine dehydrogenase (CAPADH), carboxylaminopropyl agmatine decarboxylase (CAPADC) and aminopropyl agmatine urea hydrolase (APAUH) are subjected to overexpression in escherichia coli by using a gene engineering technology, and then the escherichia coli is subjected to enzyme deactivation, so that the escherichia coli is obtained. The genetically engineered bacterium capable of producing the spermidine can be obtained by simultaneously knocking out a spermidine transport system (PotBCAD), a spermidine-N-acetyltransferase (spermidine-N-acetyltransferase) and a homoserine dehydrogenase (homoserine dehydrogenase), so that the genetically engineered bacterium capable of producing the spermidine can be obtained. The engineering bacterium greatly reduces the production cost of spermidine, has a wide application prospect, and lays a foundation for green production of spermidine.

The invention discloses a selenium-rich spirulina culture method, and belongs to the technical field of spirulina culture, the method comprises the following steps: curing spirulina by using dopamine modified sodium alginate microspheres containing magnetic particles, and carrying out two-stage culture in a culture solution with low selenium concentration and high selenium concentration containing hexanoyl-L-homoserine lactone to obtain the selenium-rich spirulina. The selenium-rich spirulina obtained through culture is high in total selenium content and organic selenium content and high in organic selenium conversion rate.

The invention discloses a method for improving the nitrogen utilization rate of eucalyptus in the field of forestry cultivation. The method comprises the following steps: deeply plowing a forest land before planting, measuring the nitrogen content of soil, preparing an activating agent containing citric acid, humic acid and ammonium molybdate, spraying, and shallow raking and uniformly mixing; ditching along planting rows, applying an MPCM material, earthing, and applying a microbial activator containing N-acyl homoserine lactone, trehalose and monopotassium phosphate through drip irrigation, so that a root system is in moderate contact with the material; the loss-control nitrogen fertilizer and the MPCM material are mixed in the planting period, the fast-growing period and before canopy closure, and then annular furrow application is carried out; by monitoring the nitrogen conditions of rhizosphere soil and leaves, a nutrient solution containing amino acid chelated nitrogen, urea and trace elements is sprayed on the leaf surfaces in good time. The MPCM material is prepared by performing pyrolysis on eucalyptus residues to prepare a charcoal substrate, performing metal doping and intelligent polymer grafting, loading nitrogen-fixing bacteria and ammonifying bacteria, and performing activation, so that accurate supply and efficient utilization of nitrogen are realized, and the growth benefits of eucalyptus are effectively improved.

This invention discloses an overexpression Met15 This invention relates to a genetically engineered strain of *Candida utilis*, its construction method, and its applications, belonging to the field of bioengineering technology. The starting strain of the genetically engineered strain described in this invention is *Candida utilis*. C. utilis CCTCC NO: M 209298, strain overexpressing O-acetylhomoserine thioylase. Met15 Gene. This invention utilizes gene recombination technology to overexpress the O-acetylhomoserine sulfhydrylase encoding gene in *Candida utilis* (…). Met15 This can increase the content of L-methionine and L-cysteine ​​in yeast cells, increase the supply of sulfur-containing amino acid precursors, and ultimately increase the yield of SAM and GSH co-production in yeast cells.

The invention discloses a recombinant genetically engineered bacterium for producing L-homoserine at high yield and application of the recombinant genetically engineered bacterium. L-homoserine transporter with higher efficiency is obtained by editing, superposing and screening multiple genes, and the yield of L-homoserine is further increased by overexpressing thrE gene; and screening to obtain the recombinant genetically engineered bacterium capable of improving the yield of the L-homoserine. The yield of the L-homoserine in a shake flask reaches 5.62 g / L, and compared with a control strain, the yield of the L-homoserine is improved by 43%; the yield of the L-homoserine in a 5L fermentation tank reaches 30.9 g / L within 72 hours, and compared with a control strain, the yield of the L-homoserine is improved by 72.2%.

The invention discloses a preparation method of L-2, 4-diaminobutyric acid dihydrochloride, which comprises the following steps: (1) taking L-homoserine as an initial raw material, and reacting with concentrated hydrochloric acid in the presence of a zinc chloride / ferrous chloride synergistic catalyst to prepare L-2-amino-4-chlorobutyric acid hydrochloride; (2) after neutralization, carrying out an acylation reaction with ethyl chloroformate to generate N-ethoxycarbonyl-L-4-chlorobutyric acid; (3) carrying out esterification with ethanol so as to obtain N-ethoxycarbonyl-L-4-chlorobutyl amino acid ethyl ester; (4) under the catalysis of sodium iodide, carrying out nucleophilic substitution reaction with phthalimide potassium salt, and cooling, crystallizing and purifying the key intermediate by dropwise adding water to obtain L-2-[(ethoxycarbonyl) amino]-4-phthalimide ethyl butyrate; and (5) finally, hydrolyzing for deprotection, and concentrating and crystallizing to obtain the L-2, 4-diaminobutyric acid dihydrochloride. The method has the advantages of mild reaction conditions, simplicity and convenience in operation, high total yield and the like, and is suitable for large-scale industrial production.

The invention relates to a homoserine-O-succinyltransferase mutant and application thereof, and belongs to the technical field of enzyme engineering. In order to solve the problem of low activity of a rate-limiting enzyme MetA for producing L-methionine through biological fermentation-enzyme catalysis coupling in the prior art, the homoserine-O-succinyl transferase mutant provided by the invention is obtained by carrying out site-directed mutagenesis on an amino acid sequence of escherichia coli wild type homoserine-O-succinyl transferase as shown in SEQ ID NO.1; comprising single mutation or multiple mutation of 25th, 65th and 113th amino acids. The OSH yield of the obtained mutant is remarkably improved compared with that of a wild type metA. According to the recombinant genetically engineered bacterium disclosed by the invention, the homoserine can be efficiently converted into the O-succinyl-L-homoserine, and sufficient precursor substances are provided for subsequent biosynthesis of L-methionine. The fermentation process of the recombinant genetically engineered bacterium is stable and reliable, is easy for large-scale production, and has a wide industrial application prospect.

The present application relates to the technical field of genetic engineering, and discloses a recombinant Escherichia coli for high-yield O-acetyl-L-homoserine and application thereof. The recombinant Escherichia coli for high-yield O-acetyl-L-homoserine is obtained by the following combination of modification strategies: in Escherichia coli W3110, a gene encoding homoserine O-acetyltransferase is integrated into a gene site encoding L-arginine ABC transporter ATP binding subunit, then a gene encoding phosphoacetyltransferase is knocked out, then a gene encoding transcriptional anti-terminator and mRNA stability regulator is knocked out, then a gene encoding ATP-NAD kinase is integrated into a gene site encoding NADPH-dependent aldehyde reductase, and finally a gene promoter of acetyl-CoA synthetase is replaced by a Ptrc promoter to obtain the recombinant Escherichia coli. The recombinant Escherichia coli is used for fermentation to produce O-acetyl-L-homoserine, and has the advantage of high yield. metx artp patz cspc ppnk yahk acs ​​​​​​​

The present application relates to a kind of L-homoserine production of recombinant genetically engineered bacteria construction method, and its application in the microbial fermentation preparation L-homoserine in.In the present application, the beneficial effects mainly reflect: the present application provides a kind of L-homoserine production of recombinant genetically engineered bacteria and its construction method, and its application in the microbial fermentation preparation L-homoserine;L-homoserine is produced using the recombinant genetically engineered bacteria of the present application by fermentation method, raw material glucose is low in cost, mild condition, environment friendly;Using the engineering bacteria of the present application, L-homoserine production is significantly improved, and has good application prospect.