105 results about "Lysine decarboxylase" patented technology

The invention relates to a method for preparing 1,5-pentanediamine. The method comprises the step of adding lysine decarboxylase into a lysine fermentation broth to synthesize 1,5-pentanediamine. The method utilizes the lysine fermentation broth but not purified lysine as the substrate, so that the process is simpler and more economical.

To provide a polyamide resin excellent in lasting thermal stability and having a high biomass ratio.A polyamide resin comprising adipic acid units, pentamethylenediamine units and 6-aminocaproic acid units as constituents, wherein the weight ratio of the sum of the adipic acid units and the pentamethylenediamine units to the 6-aminocaproic acid units is 97:3 to 75:25. The pentamethylenediamine is preferably one produced from lysine using lysine decarboxylase, lysine decarboxylase-producing cells or a treated product of the cells.

The present invention is directed to mutants of lysine decarboxylase, nucleic acids encoding the mutants, and vaccines comprising the mutants for inhibiting and reducing the development of periodontal diseases, including gingivitis and chronic periodontitis. The vaccine composition comprises a recombinant lysine decarboxylase mutant which is based on a native version of the enzyme from E. corrodens and induces production of antibodies that inhibit the activity of the lysine decarboxylase enzyme in the oral cavity. The recombinant lysine decarboxylase mutant, in one version, comprises a mutation at residue 365 or at other locations within the active site, and in a preferred embodiment is produced from E. coli in large amounts and to form inclusion bodies. The purified inclusion bodies can then be used in the vaccine composition to induce in vivo production of antibodies that inhibit the activity of native E. corrodens lysine decarboxylase.

The invention belongs to the field of biological fermentation engineering, and provides a method for producing pentamethylene diamine by using a carbon dioxide desorption process through fermentation. The method comprises the following steps: culturing cells for expressing lysine decarboxylase so as to obtain a whole-cell fermentation liquid containing pentamethylene diamine; extracting pentamethylene diamine from the whole-cell fermentation liquid obtained in the step (1), wherein carbon dioxide in the whole-cell fermentation liquid is desorbed before strong base is added into the whole-cell fermentation liquid. By adopting the method, the yield of pentamethylene diamine can be greatly increased.

The invention provides a method for preparing 1,5-pentanediamine. The method comprises the steps of: a, dissolving lysine salt to obtain an aqueous solution of lysine salt; b, adding lysine decarboxylase and vitamin B6 coenzyme to the aqueous solution of lysine salt for a decarboxylation reaction of lysine; c. filtering a 1,5-pentanediamine salt solution obtained in step b by using an ultrafiltration membrane having a interception molecular weight being 3000-6000; d. selectively adsorbing vitamin B6 coenzyme in a 1,5-pentanediamine salt ultrafiltrate obtained in step c by using macroporous adsorption resin; e, sending the enzyme-removed 1,5-pentanediamine salt solution obtained in step d to a two-chamber bipolar membrane electrodialysis device for desalting; and f. performing concentrationand dehydration on the 1,5-pentanediamine aqueous solution obtained in the step e, then performing vacuum distillation, and performing condensation on a light phase to obtain a 1,5-pentanediamine product. The preparation method of the invention has the advantages of low cost, small environmental protection pressure, and high product purity, and is suitable for industrial application.

The invention relates to a lysine decarboxylase mutant and application thereof, in particular to lysine decarboxylase modification aiming to allow lysine decarboxylase to be suitable for L-lysine production using microbial fermentation and coupling catalyzing L-lysine decarboxylic reaction to generate 1,5-pentamethylene diamine so as to use glucose to produce the 1,5-pentamethylene diamine in onestep. The lysine decarboxylase mutant has the advantages that the activity-lowered lysine decarboxylase mutant is acquired by using random mutation and high-throughput screening; when recombinant L-lysine production strains containing the lysine decarboxylase mutants are used to produce the 1,5-pentamethylene diamine in one step, the toxic effect of the 1,5-pentamethylene diamine in the system inthe early fermentation stage on thallus when the thallus uses glucose fermentation can be reduced, the balance between L-lysine and the 1,5-pentamethylene diamine can be maintained, the yield of the 1,5-pentamethylene diamine produced by the L-lysine production strains can be increased, and the quantity of the residual L-lysine is less than 2.2g / L.

The invention discloses a method for producing 1,5-pentanediamine through immobilized lysine decarboxylase. The method comprises the following steps of connecting a chitin binding domain (ChBD) gene to the N end of a lysine decarboxylase gene (CadA) to construct a fusion protein; fermenting the fusion protein to obtain a crude lysine decarboxylase enzyme solution; adding chitin into the crude enzyme solution to obtain immobilized lysine decarboxylase; finally, enabling the obtained immobilized lysine decarboxylase to participate in a decarboxylation reaction of L-lysine to prepare 1,5-1,5-pentanediamine. According to the method, the specific affinity effect of the substrate chitin and the fusion protein is skillfully utilized to adsorb the lysine decarboxylase, the cost of the immobilizedcarrier chitin is low, the immobilization efficiency is high, the activity stability of enzymes is high, and meanwhile, the procedure of protein purification can be omitted through specific affinity adsorption. The provided method achieves repeated production of 1,5-1,5-pentanediamine and can reduce the production cost, simplify the separation procedure of downstream products and enzymes and achieve remarkable economic benefits.

The invention discloses recombinant escherichia coli for efficiently producing glutaric acid and a construction method of the recombinant escherichia coli, and belongs to the technical field of metabolic engineering. According to the invention, a lysine decarboxylase gene cadA, a butanediamine transaminase gene patA and a gamma-aminobutyraldehyde dehydrogenase gene patD are obtained by cloning from an Escherichia coli MG1655 genome through a molecular biological means, and a 4-aminobutyric acid transaminase gene gabT and a succinic acid hemialdehyde dehydrogenase gene gabD are obtained by cloning from a Pseudomonas fluorescens genome. After a constructed recombinant expression vector pETM6R1-cadA-RBS01-patA-RBS02-patD-gabT-gabD is introduced into E.coli W3110, a recombinant strain Glu-02 for efficiently producing the glutaric acid is obtained through ampicillin resistance plate screening. The recombinant strain is fermented for 60 hours in a 5L fermentation tank by adopting a fed-batchfermentation strategy, the glutaric acid yield reaches 56.2 g / L, and the conversion rate is 62.2%.

The invention relates to an engineered Escherichia coli strain capable of realizing high-yield production of pentamethylene diamine and method for high-yield production of pentamethylene diamine via the same. The engineered Escherichia coli strain is Escherichia coli with an accession number of CGMCC No. 17454. The method comprises the following steps: (1) constructing engineered Escherichia colistrain TJU-cadA-1 for exogenous expression of L-lysine decarboxylase, wherein the enzyme activity of the L-lysine decarboxylase is about 100 times the enzyme activity of a no-load strain; (2) carryingout permeability treatment on L-lysine decarboxylase-rich whole cells, wherein the enzyme activity of the L-lysine-rich decarboxylase in permeabilized cells is 3-4.5 times the enzyme activity of thewhole cells; and (3) catalyzing L-lysine hydrochloride to produce pentamethylene diamine by using the permeabilized cells, wherein the yield of pentamethylene diamine is 90%-100%, and the concentration of pentamethylene diamine can reach 220 g / L or above. According to the method, the L-lysine hydrochloride is used for efficiently producing the pentamethylene diamine; and compared with the prior art, an expensive IPTG inducer is not needed in the invention, so the method has the advantages that mass transfer efficiency is high, yield is high, production cost is low, and higher economic feasibility and practicability are obtained.

Provided are CadA polypeptides with mutations that increase activity in alkaline pH compared to the wild-type lysine decarboxylase. Methods of generating such mutant polypeptides, microorganisms genetically modified to over-express the mutant polypeptides, and methods of generating such microorganisms are also provided.