Blastococcus litoris sp. nov., isolated from sea-tidal flat sediment.

Area of Science:

• Microbiology
• Bacterial Taxonomy
• Marine Biology

Background:

• The genus Blastococcus comprises Gram-positive, non-spore-forming cocci with limited species diversity.
• Marine environments, such as tidal flats, are rich sources of novel microbial life with unique metabolic capabilities.

Purpose of the Study:

• To isolate and characterize a novel bacterial strain from a Korean sea-tidal flat.
• To determine the taxonomic position of the novel strain using polyphasic characterization, including phylogenetic and chemotaxonomic analyses.
• To propose a new species within the genus Blastococcus.

Main Methods:

• Isolation and cultivation of bacterial strain GP-S2-8T from a sea-tidal flat sediment sample.
• Phenotypic characterization including morphology, growth conditions (temperature, pH, salinity), and biochemical tests (catalase, oxidase).
• Phylogenetic analysis based on 16S rRNA gene sequencing, chemotaxonomic analyses (cell-wall peptidoglycan, whole-cell sugars, polar lipids, fatty acids), and DNA-DNA hybridization.

Main Results:

• Strain GP-S2-8T is a Gram-positive, aerobic, non-motile coccus that tolerates a wide range of temperatures, pH, and salinities.
• Phylogenetic analysis places the isolate within the genus Blastococcus.
• Chemotaxonomic data, including meso-diaminopimelic acid in peptidoglycan, rhamnose, glucose, and mannose as whole-cell sugars, MK-9(H4) as the predominant quinone, and specific fatty acid profiles, support its placement.
• DNA-DNA relatedness values between strain GP-S2-8T and type strains of the genus Blastococcus were low (14.6–48.6%), indicating genetic distinctiveness.

Conclusions:

• Strain GP-S2-8T represents a new species of the genus Blastococcus, named Blastococcus litoris sp. nov.
• The distinct phenotypic and genotypic characteristics differentiate B. litoris from previously described Blastococcus species.
• This discovery expands the known biodiversity of the Blastococcus genus and highlights the potential of marine tidal flats as reservoirs for novel bacteria.