7 results about "Polyphosphate kinase" patented technology

This invention discloses the application of engineered *Citrobacter freundii* in the fermentation synthesis of spermine. The engineered *Citrobacter freundii* is a strain overexpressing the polyphosphate kinase gene Ppk1. The engineered *Citrobacter freundii* is inoculated into a fermentation medium for fermentation culture to synthesize spermine. The synthesis and extraction method of this invention for producing spermine is simple to operate, highly reproducible, low in cost, and yields a high spermine content in the fermented bacterial cells, accounting for 12.42% of the bacterial dry weight. The extracted spermine has a purity as high as 90.26%.

This invention discloses an enzymatic method for preparing (S)-adenosylmethionine. The method uses adenosine diphosphate (ADP) and L-methionine as substrates, reacting them under the combined action of polyphosphate kinase (Ppk) and adenosylmethionine synthase (MAT) to obtain (S)-adenosylmethionine. This method produces a product with high chiral purity and high atom economy, making it more suitable for industrial production.

The application provides a polyphosphate kinase (PPK) mutant and a preparation method and application thereof, and belongs to the technical field of enzyme engineering. The polyphosphate kinase mutant is mutated on the amino acid sequence shown in SEQ ID NO. 1. The application also provides an engineering bacterium for expressing the polyphosphate kinase mutant and a construction method of the polyphosphate kinase mutant. The polyphosphate kinase mutant provided by the application has improved thermal stability compared with the wild type, and the enzyme activity can be maintained for more than 1 h under the condition of 37 DEG C, and under the same heat treatment condition, the enzyme activity is 1.5 times that of the wild type, and is more suitable for industrialization.

The present application provides an enzyme composition comprising sucrose phosphatase, UTP glucose-1-phosphate uridylyltransferase, polyphosphate kinase and the like, or a group of recombinant engineering bacteria expressing the above enzymes. By using the above enzyme composition or the recombinant engineering bacteria, UDP-glucose and its derivatives can be synthesized using sucrose as a raw material, which has application prospects in the field of biological manufacturing.

The present application relates to the field of biological catalysis, and discloses a method for preparing creatine phosphate by immobilized enzyme catalysis, which comprises the following steps: mixing gelatin and a positive charge modifier to obtain a carrier liquid; adding creatine and magnesium salt to a crude creatine kinase solution for pre-incubation to realize conformational locking, then mixing with the carrier liquid and dropping into a low-temperature coagulation bath to solidify into gel microspheres, and then cross-linking and washing to obtain immobilized creatine kinase particles; finally, adding substrates, sodium hexametaphosphate, polyphosphate kinase and immobilized particles into a reaction system for reaction, and then separating and collecting the supernatant to obtain creatine phosphate. The present application protects the three-dimensional conformation of the active center of the enzyme by pre-incubation, uses the positive micro area of the carrier to electrostatically enrich the substrates to accelerate mass transfer, and introduces an auxiliary enzyme to construct an in-situ substrate regeneration system to re-phosphorylate the by-product adenosine diphosphate into adenosine triphosphate. The present application eliminates the feedback inhibition of the product, reduces the cost of raw materials, and improves the overall catalytic efficiency.

The application discloses a polyphosphate kinase BsPPK mutant and construction and application of a producing strain thereof, and belongs to the technical field of genetic engineering. The application carries out site-directed mutation on polyphosphate kinase BsPPK from the genus Bredia through homologous modeling, molecular docking and multiple sequence alignment, mutates lysine at the 92th position of the wild type BsPPK into alanine, threonine at the 95th position into alanine, and serine at the 205th position into arginine, and obtains a combined mutant BsPPK-K92A / T95A / S205R. Enzyme activity determination results show that the specific enzyme activity of the mutant is increased by 324.4% compared with the wild type, and the catalytic efficiency on AMP is significantly improved. When the mutant is applied to synthesis of UDP-Gal and derivative products thereof, only 15 mM AMP is needed to achieve a similar yield obtained by using 30 mM AMP for the wild type, and the nucleotide consumption is reduced by 50%.

This invention belongs to the field of biotechnology and discloses a method for the continuous preparation of β-nicotinamide mononucleotide (NMN). The invention covalently immobilizes four functional enzymes—ribokinase, phosphoribosylpyrokinase, nicotinamide phosphoribosyltransferase, and polyphosphate kinase—on an alkali-activated epoxy resin microsphere carrier to prepare a multi-enzyme composite catalyst. Using D-ribose, nicotinamide, and low-polymerization-degree polyphosphate as substrates, a small amount of ATP-initiating reaction solution is used to carry out continuous catalysis in a packed bed reactor. Polyphosphate kinase enables in-situ, zero-distance ATP regeneration, highly coupling ATP regeneration with NMN synthesis, significantly improving energy utilization and cascade catalytic efficiency. This invention solves the problems of high ATP consumption, non-recoverable enzymes, difficulty in continuous production, and limited diffusion of intermediate products in traditional enzymatic methods. The process is stable, green, safe, and suitable for industrial scale-up.