30 results about "Homoserine dehydrogenase" patented technology

Novel polynucleotides derived from microorganisms belonging to coryneform bacteria and fragments thereof, polypeptides encoded by the polynucleotides and fragments thereof, polynucleotide arrays comprising the polynucleotides and fragments thereof, recording media in which the nucleotide sequences of the polynucleotide and fragments thereof have been recorded which are readable in a computer, and use of them.

Disclosed is a strain of Escherichia sp., capable of producing O-acetyl homoserine in high yield, with the introduction and enhancement therein of the activity of: homoserine acetyl transferase, aspartokinase and homoserine dehydrogenase; and at least one enzyme selected from a group consisting of phosphoenolpyruvate carboxylase, aspartate aminotransferase and aspartate semi-aldehyde dehydrogenase. Also, a method of producing O-acetyl homoserine using the strain is provided.

The present invention relates to a microorganism producing L-methionine precursor, O-succinylhomoserine, 1) the homoserine O-succinyltransferase activity (EC2.3.1.46) is introduced and enhanced, wherein the homoserine O-succinyltransferase activity is feed back resistant to methionine; and 2) the aspartokinase or homoserine dehydrogenase activity (EC2.7.2.4 or 1.1.1.3) is enhanced, and a method of producing L-methionine precursor using the microorganism.

The invention discloses a method for synthesizing ursodeoxycholic acid (UDCA) and high-chiral-purity D-amino acid based on an enzyme-method coupling technology. The method comprises the following steps: putting chenodeoxycholic acid and alpha-ketonic acid into a solution system containing 7alpha-HSDH (Homoserine Dehydrogenase), DAADH and NADP (Nicotinamide Adenine Dinucleotide Phosphate) and carrying out enzyme catalysis reaction; separating a reaction solution by adopting an ultra-filtration membrane to obtain a concentrated mixed enzyme solution; regulating the pH (Potential of Hydrogen) ofa dialysis solution and crystallizing; filtering and separating to obtain 7-KLCA wet powder and filtrate; carrying out chromatographic treatment on the filtrate to obtain the D-amino acid; putting the7-KLCA wet powder into a solution system containing glucose, the NADP, the 7alpha-HSDH and GDH (Glutamate Dehydrogenase) and carrying out enzyme catalysis reaction; separating the reaction solution by adopting the ultra-filtration membrane to obtain the concentrated mixed enzyme solution; crystallizing, filtering and separating the dialysis solution, so as to obtain ursodeoxycholic acid. By adopting the method provided by the invention, UDCA and the high-chiral-purity D-amino acid can be obtained at the same time, the enzyme utilization rate is high, synthesis steps are simple and the cost isreduced; meanwhile, a metal reduction reagent and an organic solvent do not need to be added in a reaction process and conditions are mild; the method is environmentally friendly and is suitable forindustrial production.

Process for the production of -lysine by constructing a recombinant microorganism which has a deregulated lysine 2,3-aminomutase gene and at least one deregulated gene selected from the group (i) which consists of aspartokinase, aspartatesemialdehyde dehydrogenase, dihydrodipicolinate synthase, dihydrodipicolinate reductase, tetrahydrodipicolinate succinylase, succinyl-amino-ketopimelate transaminase, succinyl-diamino-pimelate desuccinylase, diaminopimelate epimerase, diaminopimelate dehydrogenase, arginyl-tRNA synthetase, diaminopimelate decarboxylase, pyruvate carboxylase, phosphoenolpyruvate carboxylase, glucose-6-phosphate dehydrogenase, transketolase, transaldolase, 6-phosphogluconolactonase, fructose 1,6-biphosphatase, homoserine dehydrogenase, phophoenolpyruvate carboxykinase, succinyl-CoA synthetase, methylmalonyl-CoA mutase, provided that if aspartokinase is deregulated as gene (i) at least a second gene (i) other than aspartokinase has to be deregulated, and cultivating said microorganism.

A method for producing L-threonine using a microorganism is provided. In the method, additional one or more copies of each of the phosphoenolpyruvate carboxylase (ppc) gene and the threonine operon are integrated into a particular site of the chromosomal DNA of a microorganism, while its inherent ppc gene and threonine operon remain. Accordingly, two or more ppc genes and threonine operons are included in the chromosomal DNA of the microorganism to thereby enhance the expression of the ppc gene encoding an enzyme to convert phosphoenolpyruvate to a threonine biosynthesis precursor, oxaloacetete, and the genes encoding enzymes involved in the synthetic pathway of threonine from oxaloacetate, including thrA (aspartokinasel-homoserine dehydrogenase), thrB (homoserine kinase), and thrC (threonine synthase), thereby markedly increasing L-threonine productivity.

Belonging to the field of bioengineering, the invention relates to construction and application of C.glutamicum subspecies lactofermentum with high L-methionine yield. The methionine high-yielding recombinant strain C.glutamicum subspecies lactofermentum QW102 / pJYW-4-hom<m>-lysC<m>-brnFE provided by the invention is preserved in China Center for Type Culture Collection with a preservation number of CCTCC M2014232. The recombinant strain has the genetic characteristics of: expression of transport protein BrnFE, expression of aspartokinase fragment lysC and homoserine dehydrogenase fragment hom, and deletion of thrB and mcbR genes on a genome at the same time. According to the invention, by a genetic engineering method, a recombinant strain with high methionine yield is obtained. The invention also provides a method for high yield of L-methionine by the recombinant strain.

The invention relates to a genetically engineered bacterium for high production of L-homoserine. The expression of an L-homoserine kinase encoding gene thrB in the bacterium is weakened or eliminated.An aspartate kinase feedback inhibition mutant gene lysC, a homoserine dehydrogenase feedback inhibition mutant gene hom, an overexpression aspartate kinase feedback inhibition mutant gene thrA and atransporter gene are further intensively expressed. The L-homoserine high-producing strain constructed by the invention can produce L-homoserine with a relatively high level, and in the optimal embodiment, after the genetically engineered bacterium disclosed by the invention is fermented for 72 hours, the content of the L-homoserine can reach 63.2 + / -5.4 g / L.

The invention provides a genetic engineering bacterium capable of producing uridine at high yield as well as a building method and application thereof. The genetic engineering bacterium is characterized in that pyrimidine nucleoside operons pyrBCAKDFE with the nucleotide sequence shown as SEQ ID NO:1 is integrated on a genome of colon bacillus; the starting is realized by a strong promoter P[trc];a uridine synthesis path is reconstituted; the self PRPP synthetase coding gene prsA on the genome is subjected to dual copying, and the starting is realized by the strong promoter P[trc]; meanwhile,the activity of udk, udp, and rihA, rihB and rihC is lacked; the thrA activity is lacked; the argF activity is lacked. The genetic engineering bacterium is applied to fermentation production of uridine; 40 to 67g / L of uridine can be produced after the fermentation is performed for 40 to 70h in a 5L fermentation tank; the maximum production intensity can reach 1.5g / (L*h); the glucoside conversionrate is 15 to 25 percent; the genetic engineering bacterium belongs to the highest level for producing the uridine by the fermentation method reported in the prior art.

The present invention relates to a compound of general formula IThe present invention also relates to a method of producing N-acetyl homoserine and / or derivatives thereof, the method comprisingcontacting at least one recombinant cell in an aqueous medium with acetate wherein the recombinant cell comprises an increased activity relative to a wild type cell of(a) an enzyme E1, a homoserine dehydrogenase (EC1.1.1.3) and / or an enzyme E5, an aspartokinase (EC2.7.2.4); and(b) an enzyme E2, a homoserine O-acetyl transferase (EC2.3.1.31)and the acetate is maintained at a concentration of at least about 0.001 g / L in the aqueous medium.

The invention relates to a homoserine dehydrogenase gene inactivation method of Bacillus subtilis, which comprises the following steps: establishing a PCR (polymerase chain reaction) product plasmid for homologous recombination, wherein the recombinant plasmid is composed of a pMD18-T vector, a kanamycin resistance gene and a homoserine dehydrogenase gene, and the homologous recombinant DNA (deoxyribonucleic acid) segment contains a homoserine dehydrogenase gene for substituting knock-out gene and a kanamycin resistance gene inserted in the middle of the homoserine dehydrogenase gene; and carrying out PCR amplification on the homoserine dehydrogenase gene and kanamycin resistance gene inserted in the middle of the homoserine dehydrogenase gene from the recombinant plasmid so as to obtain the single-chain PCR product, electrically transforming the single-chain PCR product into a Bacillus subtilis competent cell to obtain a transformant, and screening the positive transformant to obtain the homoserine dehydrogenase gene inactivated mutant strain. Compared with the existing technique for transforming the homoserine dehydrogenase recombinant plasmid into the Bacillus subtilis competent cell, the method is more simple and time-saving.

The invention discloses a biological method for synthesizing spermidine, which belongs to the technical field of biological engineering. The invention constructs genetic engineering bacteria, which can synthesize spermidine using homoserine and putrescine (butanediamine) as substrates. Specifically, homoserine dehydrogenase is used to dehydrogenate homoserine to form aspartic semialdehyde and NADH, and carboxyspermidine dehydrogenase uses NADH as a coenzyme to synthesize aspartic semialdehyde and putrescine into carboxyspermidine, and realize Coenzyme regeneration produces NAD, and finally, carboxyspermidine decarboxylase decarboxylates carboxyspermidine to produce spermidine. The method for biosynthesizing spermidine provided by the invention has the advantages of simple production process, readily available raw materials and low cost, and has good industrial application prospect.

The present invention relates to a microorganism producing L-methionine precursor, O-succinylhomoserine, 1) the homoserine O-succinyltransferase activity (EC2.3.1.46) is introduced and enhanced, wherein the homoserine O-succinyltransferase activity is feed back resistant to methionine; and 2) the aspartokinase or homoserine dehydrogenase activity (EC2.7.2.4 or 1.1.1.3) is enhanced, and a method ofproducing L-methionine precursor using the microorganism.

A method for producing L-threonine using a microorganism is provided. In the method, additional one or more copies of each of the phosphoenolpyruvate carboxylase (ppc) gene and the threonine operon are integrated into a particular site of the chromosomal DNA of a microorganism, while its inherent ppc gene and threonine operon remain. Accordingly, two or more ppc genes and threonine operons are included in the chromosomal DNA of the microorganism to thereby enhance the expression of the ppc gene encoding an enzyme to convert phosphoenolpyruvate to a threonine biosynthesis precursor, oxaloacetete, and the genes encoding enzymes involved in the synthetic pathway of threonine from oxaloacetate, including thrA (aspartokinasel-homoserine dehydrogenase), thrB (homoserine kinase), and thrC (threonine synthase), thereby markedly increasing L-threonine productivity.

The present disclosure relates to a genetically engineered strain with high production of uridine and its construction method and application. The strain was constructed as follows: heterologously expressing pyrimidine nucleoside operon sequence pyrBCAKDFE (SEQ ID NO:1) on the genome of E coli prompted by strong promoter Ptrc to reconstruct the pathway of uridine synthesis; overexpressing the autologous prsA gene coding PRPP synthase by integration of another copy of prsA gene promoted by strong promoter Ptrc on the genome; deficiency of uridine kinase, uridine phosphorylase, ribonucleoside hydrolase, homoserine dehydrogenase I and ornithine carbamoyltransferase. When the bacteria was used for producing uridine, 40-67 g / L uridine could be obtained in a 5 L fermentor after fermentation for 40-70 h using the technical scheme provided by the disclosure with the maximum productivity of 0.15-0.25 g uridine / g glucose and 1.5 g / L / h respectively which is the highest level of fermentative producing uridine reported at present.