13 results about "Aspartate kinase" patented technology

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.

The invention discloses genetically engineered corynebacterium glutamicum and an application of the genetically engineered corynebacterium glutamicum in preparation of ectoine, and the genetically engineered corynebacterium glutamicum contains an L-diaminobutyric acid transaminase gene ectB, an L-diaminobutyric acid acetyltransferase gene ectA and an ectoine synthetase gene ectC, the invention relates to an aspartic acid transferase gene aspB, an aspartic acid kinase gene lysC and an aspartic acid semialdehyde dehydrogenase gene asd, wherein the nucleotide sequences of the gene aspB, the gene lysC and the gene asd are respectively as shown in SEQ ID NO.4, SEQ ID NO.5 and SEQ ID NO.6. The invention further discloses a preparation method of the aspartic acid transferase gene aspB, the aspartic acid kinase gene lysC and the aspartic acid semialdehyde dehydrogenase gene asd. After the recombinant corynebacterium glutamicum constructed by the invention is fermented for 60 hours, the yield of ectoine can reach 50g / L. The genetically engineered corynebacterium glutamicum disclosed by the invention has important practical significance on industrial production and large-scale application of ectoine.

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 invention relates to the technical field of microbial fermentation, and particularly discloses a recombinant microorganism for producing threonine and application of the recombinant microorganism. Compared with an original strain, the recombinant microorganism for producing threonine has the advantages that the expression quantity of thrL is reduced, and the expression quantity of threonine / homoserine export protein mutants, aspartate kinase / homoserine dehydrogenase I mutants, homoserine kinase and threonine synthase is increased; the threonine / homoserine ex-transport protein mutant is characterized in that the second site in the protein sequence of threonine / homoserine ex-transport protein is mutated from proline to leucine; 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. The invention constructs a novel recombinant microorganism for producing threonine, and provides a novel method for improving the fermentation production efficiency of threonine.

Disclosed is use of a Glycine max aspartate kinase / homoserine dehydrogenase family gene GmAK-HSDH. The gene GmAK-HSDH encoding a GmAK-HSDH protein has the nucleotide sequence set forth in SEQ ID NO: 1. A constructed overexpression vector pBA002-GmAK-HSDH is transformed into a recipient material JACK by cotyledonary node transformation.

This invention provides an engineered bacterium for producing ectoine, its preparation method, and its application. The engineered bacterium is prepared using the following steps: using Corynebacterium glutamicum as the starting strain, feedback inhibition of 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 combinations of aspartate semialdehyde dehydrogenase Asd, aspartate transaminase AspB, or 6-phosphogluconate dehydrogenase Gnd is enhanced to further increase the yield of ectoine.

The invention provides an engineering bacterium for producing Ectoine as well as a preparation method and application thereof, and the engineering bacterium is prepared by the preparation method comprising the following steps: taking corynebacterium glutamicum as a starting strain, relieving feedback inhibition of aspartate kinase LysC, reducing activity of gene lysE for coding lysine efflux permease, and obtaining the Ectoine-producing engineering bacterium. And expressing an Ectoin synthetic gene cluster ectABC. On the basis, the activity of any one or a combination of at least two of diaminobutyric acid acetyltransferase EctA, pyruvate carboxylase Pyc or aspartate kinase LysC is enhanced, and / or the activity of any one or a combination of two of malic acid quinone oxidoreductase Mqo or homoserine dehydrogenase Hom is reduced, so that the yield of Ectoine is further improved.

The invention belongs to the technical field of microbial metabolism and genetic engineering, and relates to construction and application of engineering bacteria for producing L-homoserine. The construction method of the high-yield L-homoserine engineering bacteria provided by the invention is characterized in that escherichia coli (E.coli Bio-67727) for producing threonine is used as an original strain; a homoserine kinase coding gene thrB and a homoserine O-succinyltransferase coding gene metA are knocked out, and the expression of aspartate kinase I ThrA, aspartate semialdehyde dehydrogenase Asdbs, aspartate kinase III LysCpa, glucokinase Glk and a homoserine extracellular transport protein RhtA is enhanced. The engineering bacteria constructed by the invention can accumulate 156.2 g / L of L-homoserine after being fermented for 80 hours. The engineering bacterium does not carry plasmids, induction is not needed in the fermentation process, control is easy, and application to industrial production is facilitated.

This disclosure provides the construction of a LysC scanning library for aspartate kinase using Retrotron editing technology, the screening of mutants, and their applications, belonging to the fields of biotechnology and genetic engineering technology. Specifically, this disclosure constructs a mutant library of an in situ whole-genome deep mutant library of aspartate kinase using novel Retrotron editing technology. The mutants in the library can significantly increase the production of amino acids such as lysine, threonine, and isoleucine.

The present application relates to an aspartate kinase mutant and an amino acid production method using same.

The application discloses a recombinant corynebacterium glutamicum with high yield of tetrahydropyrimidine and application thereof, and belongs to the technical field of bioengineering. S301Y By overexpressing aspartate kinase Lyc and aspartate semialdehyde dehydrogenase Asd, the supply of precursor aspartate semialdehyde can be increased. By inserting a repressor protein BetI binding sequence in the dapA promoter region of dihydropyridine dicarboxylic acid synthetase and overexpressing the repressor protein BetI, the content of by-product L-lysine in the fermentation liquor can be greatly reduced. By inserting a repressor protein LmrA binding sequence in the gltA promoter region of citrate synthase and overexpressing the repressor protein LmrA, the imbalance between cell growth and acid fermentation is solved, the supply of precursors oxaloacetate and acetyl CoA is increased, the yield of tetrahydropyrimidine is greatly improved, the yield is as high as 45.5 g / L, and the yield rate is as high as 0.25 g / g glucose.

The invention provides an engineering bacterium for producing Ectoine as well as a preparation method and application thereof, and the engineering bacterium is prepared by the preparation method comprising the following steps: taking corynebacterium glutamicum as a starting strain, relieving feedback inhibition of aspartate kinase LysC, reducing activity of gene lysE for coding lysine efflux permease, and obtaining the Ectoine-producing engineering bacterium. And expressing an Ectoin synthetic gene cluster ectABC. On the basis, the activity of any one or a combination of at least two of diaminobutyric acid acetyltransferase EctA, pyruvate carboxylase Pyc or aspartate kinase LysC is enhanced, and / or the activity of any one or a combination of two of malic acid quinone oxidoreductase Mqo or homoserine dehydrogenase Hom is reduced, so that the yield of Ectoine is further improved.

The invention relates to the technical field of microorganisms, and particularly discloses application of a microorganism with reduced lysine decarboxylase activity in fermentation production of L-threonine. The research finds that the fermentation yield of threonine can be improved by reducing the activity of lysine decarboxylase, and further the application of the microorganism with reduced activity of lysine decarboxylase in fermentation production of L-threonine is provided. According to the microorganism, the activity of lysine decarboxylase is reduced; furthermore, the expression quantity of threonine operon leader peptide of the microorganism is reduced; the 433rd site of the protein sequence of the aspartate kinase / homoserine dehydrogenase I is mutated from glycine to arginine to form an aspartate kinase / homoserine dehydrogenase I mutant, and the expression quantity of the aspartate kinase / homoserine dehydrogenase I mutant is increased; the expression quantity of homoserine kinase and threonine synthase is increased. The invention provides a novel microorganism and an effective method for fermentation production of threonine.