Oceanibaculum nanhaiense sp. nov., isolated from surface seawater

Area of Science:

• Microbiology
• Marine Biology
• Taxonomy

Background:

• The South China Sea harbors diverse microbial life, yet many species remain uncharacterized.
• Understanding marine bacterial taxonomy is crucial for ecological and biotechnological applications.

Purpose of the Study:

• To taxonomically characterize a novel bacterial strain, L54-1-50^T, isolated from South China Sea surface seawater.
• To determine if strain L54-1-50^T represents a new species within the genus Oceanibaculum.

Main Methods:

• Phenotypic characterization including Gram staining, cell shape, oxidase, catalase tests, and growth conditions (salinity, pH, temperature).
• Genotypic analysis using 16S rRNA gene sequencing, digital DNA-DNA hybridization (dDDH), and average nucleotide identity (ANI).
• Analysis of cellular fatty acids, respiratory quinones, and polar lipids; determination of DNA G+C content.

Main Results:

• Strain L54-1-50^T is a Gram-negative, rod-shaped, aerobic bacterium.
• Phylogenetic analysis placed strain L54-1-50^T within the genus Oceanibaculum, with 16S rRNA gene similarity of 98.8% to O. indicum and 97.7% to O. pacificum.
• Low dDDH (<35.4%) and ANI (<88.3%) values supported its distinction from related species. Major fatty acids included summed feature 8, C16:0, and C18:1 2-OH; Q-10 was the respiratory quinone; DNA G+C content was 65.1%.

Conclusions:

• Strain L54-1-50^T exhibits distinct phenotypic and genotypic features differentiating it from known Oceanibaculum species.
• The combined data strongly support the classification of strain L54-1-50^T as a novel species, Oceanibaculumnanhaiense sp. nov.
• The proposed type strain is L54-1-50^T (=KCTC 52312^T=MCCC 1A05150^T).