Aggregatimonas sangjinii gen. nov., sp. nov., a novel silver nanoparticle synthesizing bacterium belonging to the family Flavobacteriaceae

Taxonomic, genomic, and ecological insights into a novel Flavobacteriaceae strain from coastal tidal flats

BACKGROUND

Tidal flats are vital coastal ecosystems that play a significant role in organic carbon accumulation and biogeochemical cycles. Members of the family Flavobacteriaceae is known for its ability to degrade complex organic matter, including polysaccharides. However, the ecological roles and metabolic capabilities of Flavobacteriaceae in tidal flat environments remain underexplored.

RESULTS

In this study, we isolated and characterized a novel bacterium, strain NBU2967T, from the tidal flats of Meishan Island in the East China Sea. Phylogenetic and genomic analyses identified this strain as a new genus and species within the family Flavobacteriaceae, for which we propose the name Meishania litoralis gen. nov., sp. nov. Comprehensive polyphasic characterization, including morphological, physiological, chemotaxonomic, and genomic analyses, confirmed its distinct taxonomic status. Genomic analysis revealed a diverse set of carbohydrate-active enzymes (CAZymes), along with multiple metabolic pathways associated with carbon and sulfur cycling, highlighting the strain's potential adaptation to organic-rich marine environments. Comparative genomic and pangenome analyses further demonstrated significant genetic divergence from related taxa. Environmental distribution data revealed that the newly proposed genus Meishania is widely distributed across global marine ecosystems.

CONCLUSIONS

We isolated and characterized a novel bacterium, designated NBU2967T (= KCTC 82912 T = MCCC 1K06391T), for which we propose the name Meishania litoralis gen. nov., sp. nov. This strain is classified as a new genus within the family Flavobacteriaceae. The strain's ability to process both carbon and sulfur compounds underscores its ecological significance in marine ecosystems. These findings provide novel insights into the ecological functions of the family Flavobacteriaceae in coastal tidal flats environments and enhance our understanding of microbial-mediated degradation and transformation of chemical compounds in dynamic coastal ecosystems.

Green Silver Nanoparticles: An Antibacterial Mechanism

Silver nanoparticles (AgNPs) are a promising tool in the fight against pathogenic microorganisms. "Green" nanoparticles are especially valuable due to their environmental friendliness and lower energy consumption during production, as well as their ability to minimize the number of toxic by-products. This review focuses on the features of AgNP synthesis using living organisms (bacteria, fungi, plants) and the involvement of various biological compounds in this process. The mechanism of antibacterial activity is also discussed in detail with special attention given to anti-biofilm and anti-quorum sensing activities. The toxicity of silver nanoparticles is considered in light of their further biomedical applications.

Synthesis of Silver Nanoparticles Using Aggregatimonas sangjinii F202Z8T and Their Biological Characterization

The aim of this study is to describe the general features and eco-friendly biosynthesis of silver nanoparticles (AgNPs) from the marine bacterium Aggregatimonas sangjinii F202Z8T. To the best of our knowledge, no previous study has reported the biosynthesis of AgNPs using this strain. The formation of AgNPs using F202Z8T was synthesized intracellularly without the addition of any disturbing factors, such as antibiotics, nutrient stress, or electron donors. The AgNPs were examined using UV-vis spectrophotometry, transmission electron microscopy, energy-dispersive X-ray spectroscopy, nanoparticle tracking analysis, and Fourier transform infrared spectrometry. The UV-vis spectrum showed a peak for the synthesized AgNPs at 465 nm. The AgNPs were spherical, with sizes ranging from 27 to 82 nm, as denoted by TEM and NTA. FTIR showed various biomolecules including proteins and enzymes that may be involved in the synthesis and stabilization of AgNPs. Notably, the AgNPs demonstrated broad-spectrum antibacterial effects against various pathogenic Gram-positive and Gram-negative bacteria, including Escherichia coli, Bacillus subtilis, and Staphylococcus aureus. The minimum inhibitory concentrations and minimum bactericidal concentrations of the F202Z8T-formed AgNPs were 80 and 100 µg/mL, 40 and 50 µg/mL, and 30 and 40 µg/mL against E. coli, B. subtilis, and S. aureus, respectively. This study suggests that A. sangjinii F202Z8T is a candidate for the efficient synthesis of AgNPs and may be suitable for the formulation of new types of bactericidal substances.