16 results about "Citrobacter freundii" patented technology

The invention discloses an application of engineered citrobacter freundii in fermentation synthesis of a stable body. The engineered citrobacter freundii is citrobacter freundii overexpressing a polyphosphate kinase gene Ppk1. The stable body prepared by fermenting the engineered citrobacter freundii is rich in polyphosphates and polyamines, particularly, the content of the polyamines can be up to 21wt%, the polyphosphates in the stable body can store the polyamines in an ionic bond combination mode, the combined polyamines are insoluble in water, a natural anion coating is generated, and the stability of the stable body is improved. And the sustained-release tablet is not easily taken by intestinal epithelial cells, so that the sustained-release tablet has a certain sustained-release effect. The medicine prepared by taking the compound as a main active ingredient shows a remarkable curative effect in ulcerative colitis treatment, has the comprehensive effects of reducing oxidative stress, enhancing the anti-inflammatory ability of a body and regulating immunity, is suitable for patients of all ages, and has outstanding application value and market prospect.

The invention provides a citrobacter freundii phage and an application thereof. The bacteriophage is a citrobacter freundii bacteriophage CFP2505001, and the preservation number is CCTCC (China Center For Type Culture Collection) NO: M20251306. The bacteriophage has excellent lysis activity, thermal stability and pH stability, can efficiently perform targeted lysis on multi-drug-resistant citrobacter freundii, significantly reduces the infection death rate of Japanese eels, and provides a new microbial resource and application approach for green prevention and control of citrobacter freundii diseases in aquaculture.

This invention belongs to the field of microbial technology and discloses a strain of *Citrobacter freundii* bacteriophage PRF337, its bacteriophage composition, and its applications. The *Citrobacter freundii* bacteriophage PRF337 was deposited on May 26, 2025, at the China General Microbiological Culture Collection Center (CGMCC), located at No. 3, Courtyard 1, Beichen West Road, Chaoyang District, Beijing, with accession number CGMCC No. 46489. The bacteriophage PRF337 exhibits broad-spectrum bactericidal activity against *Citrobacter freundii*, capable of lysing *Citrobacter freundii* strains containing different virulence genes and from different sources. It also possesses certain temperature and pH stability and can be used as an active ingredient in pharmaceutical preparations, environmental disinfectants, and water purifiers. It can effectively control *Citrobacter freundii* infection in aquatic animals such as fish and shrimp in aquaculture environments and can also be used for the purification of pathogens in aquatic environments. It is safe to use and effectively avoids the problems of antibiotic residues and pathogen resistance caused by antibiotic use.

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%.

The invention belongs to the technical field of gene engineering and enzyme engineering, and aims to provide a tyrosine phenol lyase mutant which is higher in catalytic efficiency and more suitable for industrial production of levodopa and is derived from citrobacter freundii, and compared with a wild tyrosine phenol lyase type, the tyrosine phenol lyase mutant has T49R or / and M379R mutation; the amino acid sequence of the tyrosine phenol lyase wild type is shown as SEQ ID NO.2 in a sequence table. The mutant and the engineering strain provided by the invention have the huge advantages of high catalytic efficiency and high product yield.

The invention discloses a 1, 3-propylene glycol production strain capable of weakening by-product accumulation and a construction method, and relates to the technical field of biology, the production strain takes a natural or artificially modified strain capable of utilizing glycerol to synthesize 1, 3-propylene glycol as an original strain, and the original strain is a natural or artificially modified strain capable of utilizing glycerol to synthesize 1, 3-propylene glycol. At least one functional gene related to glycerol oxidation or by-product generation is inactivated through gene editing technology transformation, and at least one key gene related to 1, 3-propylene glycol reduction synthesis is expressed at a high level; the starting strain is at least one of klebsiella or citrobacter freundii or at least one of artificially modified strains; according to the invention, genes such as dhaD, ldhA, pta / ackA, adhE, budA / B / C (by-product synthesis pathway) and the like are knocked out directionally through a CRISPR / Cas9 technology, so that the generation of by-products such as lactic acid, acetic acid, ethanol, 2, 3-butanediol and the like is effectively blocked. The carbon source and reduction equivalent (NADH) of the modified strain are not shunted to by-product synthesis any more, and are more used for 1, 3-propylene glycol generation, so that the problem of carbon source waste of the traditional strain is solved.

The invention relates to the fields of gene engineering, enzyme engineering and bioinformatics, and particularly discloses application of glycine free radical enzyme in preparation of propylene glycol. Transforming a glycolytic pathway of escherichia coli: knocking out phosphofructokinase, acetaldehyde dehydrogenase, lactic dehydrogenase and ethanol dehydrogenase of the strain; according to the present invention, the following genes driven by the strong promoter, such as glycerol dehydrogenase, fructose-6-phosphate aldolase, mannitol-1-phosphate dehydrogenase, and dihydroxyacetone kinase, glycine free radical enzyme and free radical activating enzyme of citrobacter freundii, are integrated in the genome so as to enhance the metabolic pathway for synthesizing 1, 2-propylene glycol, and finally obtain the genetically engineered bacterium, wherein the genes comprise glycerol dehydrogenase, fructose-6-phosphate aldolase, mannitol-1-phosphate dehydrogenase, dihydroxyacetone kinase, glycine free radical enzyme and free radical activating enzyme of citrobacter freundii. The R-1, 2-propylene glycol produced by using the genetically engineered bacterium through a biological method can be applied to the fields of medicines, cosmetics, foods and the like, and high-added-value products are developed to meet the requirements of different fields on the R-1, 2-propylene glycol.

This invention relates to the field of microbial technology, and more particularly to a broad-spectrum Aeromonas hydrophila phage and its applications. The Aeromonas hydrophila phage AhP2505006 is classified as follows: Aeromonas hydrophila Phage AhP2505006, with accession number CCTCC NO: M20251307, exhibits cross-species lytic activity. It can effectively lyse *Aeromonas*, *Vibrio parahaemolyticus* and *Vibrio alginolyticus*, and *Citrobacter freundii*. It also possesses excellent targeting ability against multidrug-resistant strains and broad host spectrum characteristics, achieving a lysis rate of up to 80% against multidrug-resistant *Aeromonas hydrophila*. In the prevention and control of diseases caused by various pathogens, or in practical scenarios facing the limitations of traditional antibiotics and highly specific bacteriophages, it has become a highly promising solution.

The invention discloses citrobacter fabricius and application of the citrobacter fabricius in improvement of compost fertilizer efficiency of tung tree fruits, the citrobacter fabricius CDC 2991-81 has been preserved in Guangdong Microbial Culture Collection Center on September 29, 2025, the preservation number is GDMCC No: 67054, and the classification number is citrobacter fabricius (Citrobacter fabricius). By adding the citrobacter fabricius into the tung tree fruit compost, the content of fatty acid in the tung tree fruit compost can be remarkably reduced, the content of ammonium nitrogen, nitrate nitrogen, phosphorus and potassium is increased, and the composting effect of tung tree fruits is remarkably improved. The invention provides a new microbial approach for the utilization of tung tree fruit compost.

The present application relates to the field of microbial technology, and more particularly to a high-temperature-resistant and titer-stable Citrobacter freundii bacteriophage and its application. The present application discloses a high-temperature-resistant and titer-stable Citrobacter freundii bacteriophage, named RDP-CI25004, and provides a powder thereof and its application. The bacteriophage has good lytic activity on Citrobacter freundii, maintains stable biological performance in a wide temperature and pH range, and can resist high-temperature treatment of 80-90 ℃. After the bacteriophage is spray-dried into a powder, the titer remains stable during long-term storage at room temperature, significantly improving the problem that the titer of the existing bacteriophage easily decreases during high-temperature processing and storage. The bacteriophage and the powder thereof are suitable for the prevention and control of Citrobacter freundii, and have good application prospect and industrial value.

The invention relates to a primer and probe combination for simultaneously detecting urinary tract klebsiella pneumoniae and drug-resistant genes through nested PCR (Polymerase Chain Reaction) and a kit of the primer and probe combination, which can solve the problem that the existing detection target lpxC of klebsiella pneumoniae is highly homologous with the sequence alignment of part of related bacteria (klebsiella oxytoca, enterobacter aerogenes and citrobacter freundii); based on the defect that a primer and probe combination designed by an existing target lpxC causes cross amplification of the bacteria and does not meet clinical requirements, and the situation that a combination of a drug-resistant gene mecA and klebsiella pneumoniae is not suitable for clinical scenes, by simultaneously identifying the klebsiella pneumoniae and common drug-resistant genes of the two bacteria, the drug-resistant genes of the two bacteria can be identified, and the drug-resistant genes of the two bacteria can be identified. The Klebsiella pneumoniae gene, namely a carbapenemase-producing drug-resistant gene KPC-2 and an extended-spectrum beta-lactamase-producing drug-resistant gene (ESBL) CTX-M-15, can be used for judging whether the Klebsiella pneumoniae is sensitive or drug-resistant Klebsiella pneumoniae and distinguishing specific drug-resistant phenotypes, so that more comprehensive and definite medication guidance can be provided for clinicians.

The invention discloses citrobacter freundii, a product and application, and belongs to the technical field of microorganisms. The preservation number of the citrobacter freundii is CGMCC (China General Microbiological Culture Collection Center) No.36707, and the preservation number of the citrobacter freundii is CGMCC The strain not only meets the basic biological safety requirement, but also can efficiently and specifically activate a key cGAS-STING innate immune signal channel in a host cell by virtue of a culture supernatant, so that the expression levels of the type I interferon and a downstream effect gene thereof are remarkably up-regulated. Due to the unique immunoregulation function, the compound shows a good inhibition effect on replication of herpes simplex virus and vesicular stomatitis virus, and a new resource and a feasible path are provided for developing an antiviral biological preparation which is based on flora immunoregulation and has broad-spectrum potential.

This invention relates to a peptide and its application in the preparation of antibacterial drugs, belonging to the field of peptide technology. The amino acid sequence of the staple peptide of this invention is G(S5)IAG(S5)IIKIKK-NH2. This includes two S5 residues cyclized to form the staple peptide. The staple peptide of this invention exhibits bioactivity against various carbapenem-resistant Gram-negative bacteria, such as *Citrobacter freundii*, *Pseudomonas aeruginosa*, *Klebsiella pneumoniae*, *Enterobacter cloacae*, *Klebsiella pneumoniae*, and *Escherichia coli*. The staple peptide sp3 kills bacteria by inducing bacterial cell membrane potential dissipation and triggering reactive oxygen species accumulation. Furthermore, sp3 exhibits good stability in trypsin, is not easily degraded, and possesses low cytotoxicity. In summary, the staple peptide sp3 has promising applications and potential in the pharmaceutical field and can serve as a candidate molecule for novel antibacterial drugs.

The invention relates to a suitable citrobacter strain and application thereof. The invention relates to citrobacter suitabilis strain J35, which is preserved in the China General Microbiological Culture Collection Center (CGMCC), the preservation number of the citrobacter suitabilis strain J35 is CGMCC No.36708, and the citrobacter suitabilis strain J35 has insecticidal activity on Sitobion avenae, Rhopalosiphum padi, Amyzus persicae, Lygocoris lucorum, Bemisia tabaci, Plutella xylostella and Spodoptera litura. The citrobacter suitabilis strain J35 has the advantages that the strain J35 is preserved in the China General Microbiological Culture Collection Center (CGMCC), and the preservation number of the citrobacter suitabilis strain J35 is CGMCC

The invention discloses citrobacter freundii and application thereof, the citrobacter freundii is excellent in performance and capable of producing hyaluronidase at high yield, and the obtained hyaluronidase is high in enzyme activity and excellent in performance and has wide application prospects.

The invention belongs to the technical field of biology, and particularly relates to a macrobrachium rosenbergii MrBeclin1 gene, recombinant protein and application. The autophagy related gene MrBeclin1 is cloned and identified from macrobrachium rosenbergii, and the autophagy related gene MrBeclin1 encodes proteins of 426 amino acids and has a conservative APG6 structural domain. The gene has the highest expression in hemolymph, is positioned in cytoplasm, and has obviously up-regulated expression in hepatopancreas and gill after being stimulated by aeromonas hydrophila or LPS (Lipopolysaccharide). Functional mechanism research shows that MrBeclin1 interference can cause significant change of autophagy related gene expression and cause serious pathological damage to hepatopancreas and gill. Meanwhile, the recombinant protein can be directly combined with aeromonas hydrophila, citrobacter freundii, staphylococcus aureus and streptococcus iniae, and can specifically inhibit the growth of the first two gram-negative bacteria. The invention systematically clarifies the key effect of MrBeclin1 in immune defense of macrobrachium rosenbergii through dual mechanisms of autophagy regulation and direct bacteriostasis, and provides a new molecular target and theoretical basis for prevention and control of shrimp epidemic diseases.