Summary auto-generated
Researchers isolated a novel fermentative bacterium, designated Orenia salinaria strain SG 3902T, from anaerobic sediments in Mediterranean solar salterns (Salin-de-Giraud, France). The strain was characterized through morphological, physiological, and genetic analyses. Cells are Gram-negative rods (1 µm × 6–10 µm) forming subterminal spores and possessing peritrichous flagella. The organism is obligately anaerobic and halophilic, growing optimally at 5–10% NaCl and 40–45°C, with growth possible between 2–25% NaCl and 10–50°C. Phylogenetic analysis based on 16S rRNA gene sequencing showed closest relationship to Orenia marismortui (95.1% similarity), but sufficient physiological and genetic differences warranted species designation. Key differences include inability to ferment mannose, glycogen, or starch (unlike O. marismortui), and distinct DNA G–C content (33.7 mol% versus 29.6 mol% for O. marismortui). The strain ferments glucose, fructose, trehalose, sucrose, maltose, cellobiose, and mannitol, producing ethanol, acetate, formate, lactate, CO2, and H2. Notably, strain SG 3902T accumulates glycine-betaine as a compatible solute and uniquely demonstrates nitrogen fixation capability within Haloanaerobiales.
Key findings
- Orenia salinaria sp. nov. is a new species of halophilic, obligately anaerobic, fermentative bacterium isolated from hypersaline Mediterranean salterns with 95.1% 16S rRNA similarity to the closest known species, Orenia marismortui
- The strain differs from O. marismortui in substrate utilization (cannot ferment mannose, glycogen, or starch) and has higher DNA G–C content (33.7 mol% vs. 29.6 mol%)
- O. salinaria accumulates glycine-betaine as a compatible solute for osmotic adaptation—the first haloanerobe known to employ this mechanism—and can utilize N2 as sole nitrogen source via apparent nitrogenase activity
- The organism is a motile, sporulating, Gram-negative rod growing optimally at 5–10% NaCl and 40–45°C, fermenting simple carbohydrates to produce ethanol, organic acids, CO2, and H2
This summary was generated automatically from the article PDF and is not part of the original publication. Refer to the PDF for the authoritative text.
Abstract
A diverse range of fermentative bacteria have been isolated from the commercial salterns of Salin-de-Giraud (Camargue, France). One of these isolates, strain SG 3902(T), has many of the morphological and physiological characteristics of the genus Orenia, as was confirmed by a phylogenetic study based on 16S rRNA gene sequencing. The closest species is Orenia marismortui, with a similarity of only 95.1%. However, strain SG 3902(T), unlike O. marismortui, does not ferment mannose, glycogen or starch. The G+C contents of the DNA also differ significantly, being 29.6 mol% for O. marismortui and 33.7 mol% for strain SG 3902(T). On the basis of these physiological and genetic differences, it is proposed that strain SG 3902(T) should be considered as a representative of a new species belonging to the genus Orenia, under the name Orenia salinaria sp. nov. The type strain is SG 3902(T) (=ATCC 700911).