6 results about "Aspartate decarboxylase" patented technology

The application discloses an L-aspartate alpha-decarboxylase with improved substrate tolerance, and the L-aspartate alpha-decarboxylase is derived from Bacillus subtilis and is subjected to site-directed mutation, i.e., phenylalanine at the 4th site is changed into tryptophan, isoleucine at the 33rd site is changed into alanine, and isoleucine at the 88th site is changed into tryptophan, so as to obtain an enzyme mutant; the mutant is recombined into E. coli, and after expression is induced, the mutant catalyzes the substrate L-aspartate to generate beta-alanine. When the substrate addition concentration of the whole cell catalytic system is 60 g / L, the conversion rates of the three enzyme mutants T4W, I33A and I88M can reach about 90%, and the yields are 1.2, 1.3 and 1.2 times of that of the unmutated strain respectively, and the substrate tolerance is obviously improved; the combined mutation also has a certain improvement on the substrate tolerance, and the finding has important research value for industrial preparation of beta-alanine.

The application relates to the technical field of enzyme catalysis. The application discloses an L-aspartate alpha-decarboxylase mutant, which is obtained after the 54th amino acid residue in the amino acid sequence of L-aspartate alpha-decarboxylase panD is mutated into X; the amino acid sequence of the L-aspartate alpha-decarboxylase panD is shown in the sequence table SEQ ID NO. 1. The method has the advantages of green environmental protection, low cost and the like.

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 provides an engineering bacterium for producing D-pantothenic acid as well as a construction method and application of the engineering bacterium. The engineering bacterium expresses an acetolactate synthase large subunit gene ilv2, an acetolactate synthase small subunit gene ilv6, a keto acid reductoisomerase gene ilvC, a dihydroxy acid dehydratase gene ilvD, a hydroxymethyltransferase gene ecm31, a keto pantoic acid reductase gene panE, an L-aspartic acid decarboxylase gene panD and a pantothenic acid synthase gene panC. According to the method, mitochondria is selected as a targeting compartment, and modular combination optimization approach positioning is adopted, so that the yield of D-pantothenic acid is greatly increased, compared with the yield of an original strain without spatial tissue optimization, the yield is increased by more than one time, the metabolic flux bottleneck in a traditional cytoplasm synthesis mode is broken through, and efficient synthesis of D-pantothenic acid is realized.

The invention provides a spatial regulation and control system, a beta-alanine production strain and a construction method and application thereof, the spatial regulation and control system comprises a recombinant protein RIDD-RGG-RGG and a recombinant protein aspC-RIAD-RIAD-panD. According to the strain, adhE, ldhA, ackA, poxB, lacI, thrA, panC, cycA and yfbQ genes are knocked out on a wild escherichia coli genome, and the recombinant protein aspC-RIAD-RIAD-panD is obtained. A beta-alanine transporter gene NCgl0580 derived from corynebacterium glutamicum is introduced in a heterologous manner, a phosphoenolpyruvate carboxylase gene ppc is over-expressed, a spatial dynamic regulation and control system containing an aspartate transaminase gene aspC and an aspartate decarboxylase gene panD is integrated, and the synthesis efficiency and the production intensity of the obtained strain are remarkably improved.

This invention relates to the field of microbial metabolic engineering, and particularly to a recombinant *Halomonas* strain that synthesizes P3HB3HP from glucose, its construction method, and its applications. This invention constructs a synthetic pathway in *Halomonas* containing enzymes such as aspartate decarboxylase and 4-aminobutyrate aminotransferase. The resulting recombinant *Halomonas* strain can synthesize P3HB3HP with a high 3HP ratio from glucose alone via the β-alanine pathway, while maintaining a high P3HB3HP yield. The recombinant *Halomonas* strain provided by this invention can produce P3HB3HP using inexpensive carbon sources, significantly reducing substrate costs and achieving high cell density, high yield, high 3HP ratio, and stable P3HB3HP synthesis.