What question did this study set out to answer?

To describe the isolation and characteristics of a novel bacterium strain from a terrestrial mud volcano.

February 28, 2026

Halomonas terrestris sp. nov., a Novel Facultatively Anaerobic Bacterium, Isolated from a Terrestrial Mud Volcano

Key Points

To describe the isolation and characteristics of a novel bacterium strain from a terrestrial mud volcano.
Isolated strain C05BenzNT from Gnilaya Gora, Russia.
Characterized growth conditions including temperature (14–42°C), pH (7.5–11.0), and salinity (up to 20% NaCl).
Analyzed metabolic capabilities with various substrates under aerobic, microaerobic, and anaerobic conditions.
Conducted phylogenetic analysis using 120 bacterial marker genes.
Strain C05BenzNT shows growth in a wide temperature range with optimal growth at 25°C.
The bacterium can utilize carbohydrates, proteins, organic acids, and specific aromatic compounds.
Phylogenetic analysis indicated close relatives are Halomonas heilongjiangensis, Halomonas flagellata and Halomonas kalidii with 88.4–88.6% ANI.

Abstract

A novel facultatively anaerobic halotolerant strain C05BenzNT was isolated from a terrestrial mud volcano Gnilaya Gora (Taman Peninsula, Russia). Cells were rod-shaped, motile and Gram-stain-negative. The temperature range for growth was 14–42°C (optimum at 25°C). The pH range for growth was 7.5–11.0 (optimum at pH 8.0). NaCl range for growth constituted up to 20% with the optimum 2.0–3.0%. Strain C05BenzNT grew aerobically, microaerobically with 1% O2 or anaerobically with nitrate as an electron acceptor. Carbohydrates, proteinaceous substrates, organic acids and various aromatic compounds were used as electron donors during aerobic growth and acetate under microaerobic and anaerobic conditions. The G+C content of the genomic DNA was 67.4%. The fatty acid profile of strain C05BenzNT was characterized by the presence of C18:1 cis11, C16:1 cis9, C16:0 as the major components. The strain possessed genes related to variable carbon and nitrogen metabolism, hinting at its substantial metabolic flexibility. The results of phylogenetic analysis based on 120 bacterial single copy conservative marker genes revealed that the closest phylogenetic relatives of strain C05BenzNT were Halomonas heilongjiangensis, Halomonas flagellata and Halomonas kalidii (with ANI range 88.4–88.6%). Based on the phenotypic, genotypic and phylogenetic characteristics of the isolate, strain C05BenzNT is considered to represent a novel species of the genus Halomonas, with proposed name Halomonas terrestris sp. nov. The type strain of Halomonas terrestris is C05BenzNT (=KCTC 8548T = CGMCC 1.61916T).

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