Pacificibacter aestuarii sp. nov., isolated from a tidal flat

Area of Science:

• Marine Microbiology
• Bacteriology
• Genomics

Background:

• Tidal flats are unique ecosystems supporting diverse microbial life.
• The genus Pacificibacter comprises marine bacteria with incompletely understood ecological roles.

Purpose of the Study:

• To characterize a novel bacterial strain isolated from a South Korean tidal flat.
• To determine the taxonomic and phylogenetic placement of strain KJ21T within the genus Pacificibacter.

Main Methods:

• Isolation and cultivation of strain KJ21T.
• Phenotypic characterization including Gram staining, motility, and growth conditions (temperature, pH, salinity).
• Chemotaxonomic analysis of major fatty acids and polar lipids.
• Genomic DNA G+C content determination.
• Phylogenetic analysis based on 16S rRNA gene sequences.
• DNA-DNA hybridization for relatedness studies.

Main Results:

• Strain KJ21T is a Gram-negative, non-motile, strictly aerobic rod.
• Optimal growth at 30°C, pH 7.0, and 2% NaCl.
• Major fatty acids include summed feature 8, C16:0, 10-methyl C19:0, and C10:0 3-OH.
• Major polar lipids include phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine, and unknown aminolipid/lipid.
• Genomic DNA G+C content is 53.9 mol%.
• Phylogenetic analysis places KJ21T within the Pacificibacter genus, closely related to P. maritimus and P. marinus.
• DNA-DNA relatedness values (46.9% and 39.8%) confirm KJ21T as a distinct species.

Conclusions:

• Strain KJ21T represents a novel species within the genus Pacificibacter.
• The proposed name for this new species is Pacificibacter aestuarii sp. nov.
• This finding contributes to the understanding of bacterial diversity in marine environments.