5 results about "Citrobacter freundii" patented technology

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%.

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 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.

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.