Polymorphobacter glacialis sp. nov., isolated from ice core

Area of Science:

• Microbiology
• Extremophile Research
• Bacterial Taxonomy

Background:

• Glaciers harbor unique microbial communities adapted to extreme cold environments.
• The genus Polymorphobacter comprises bacteria with diverse metabolic capabilities, often found in various environmental niches.

Purpose of the Study:

• To isolate and characterize a novel bacterial strain from a Tibetan glacier ice core.
• To determine the phylogenetic and taxonomic position of the novel isolate within the genus Polymorphobacter.

Main Methods:

• Isolation of bacteria from glacier ice core samples.
• Phylogenetic analysis using 16S rRNA gene sequences.
• Physiological and biochemical characterization, including growth conditions, lipid profiles, and fatty acid composition.
• DNA-DNA hybridization for taxonomic classification.

Main Results:

• A novel Gram-negative, rod-shaped bacterium, designated B555-2^T, was isolated.
• Phylogenetic analysis indicated close relatedness to Polymorphobacter fuscus and Polymorphobacter multimanifer.
• Optimal growth occurred at pH 7, 15°C, and 0.6% NaCl, with carotenoid production observed.
• DNA-DNA hybridization confirmed B555-2^T as a distinct species, proposed as Polymorphobacter glacialis sp. nov.

Conclusions:

• Strain B555-2^T represents a new species, Polymorphobacter glacialis, within the genus Polymorphobacter.
• This finding expands the known diversity of bacteria inhabiting glacial environments.
• The study provides a comprehensive taxonomic description of this novel extremophile.