Halanaerobacter jeridensis sp. nov., isolated from a hypersaline lake.

An obligatory anaerobic, moderately halophilic bacterium, designated strain CEJFG43(T), was isolated from a sample of sediment collected below the salt crust on the hypersaline El Jerid lake, in southern Tunisia. The cells of this novel strain were Gram-staining-negative, non-sporulating, motile, short rods. They grew in media with 6-30% (w/v) NaCl (optimum 15%), at 20-60 °C (optimum 45 °C) and at pH 5.5-9.5 (optimum pH 8.3). The micro-organism fermented glucose, fructose, ribose, raffinose, galactose, mannose, sucrose, maltose, xylose, mannitol, pyruvate and glycerol. The products of glucose fermentation were lactate, ethanol, acetate, H(2) and CO(2). The genomic G+C DNA content of strain CEJFG43(T) was 33.3 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain CEJFG43(T) belonged in the genus Halanaerobacter and was most closely related to Halanaerobacter lacunarum DSM 6640(T) (95.3% gene sequence similarity) and Halanaerobacter chitinivorans DSM 9569(T) (95.3%). The predominant cellular fatty acids were non-branched (C(16:0) and C(16:1)). Based on the phylogenetic and phenotypic evidence, strain CEJFG43(T) represents a novel species in the genus Halanaerobacter for which the name Halanaerobacter jeridensis sp. nov. is proposed. The type strain is CEJFG43(T) ( = DSM 23230(T) = JCM 16696(T)).

Characterization of Halanaerocella petrolearia gen. nov., sp. nov., a new anaerobic moderately halophilic fermentative bacterium isolated from a deep subsurface hypersaline oil reservoir : New taxa: Firmicutes (Class Clostridia, Order Halanaerobiales, Halobacteroidaceae, Halobacteroides).

An anaerobic, halophilic, and fermentative bacterium, strain S200(T), was isolated from a core sample of a deep hypersaline oil reservoir. Cells were rod-shaped, non-motile, and stained Gram-positive. It grew at NaCl concentrations ranging from 6 to 26% (w/v), with optimal growth at 15% (w/v) NaCl, and at temperatures between 25 and 47°C with an optimum at 40-45°C. The optimum pH was 7.3 (range 6.2-8.8; no growth at pH 5.8 and pH 9). The doubling time in optimized growth conditions was 3.5 h. Strain S200(T) used exclusively carbohydrates as carbon and energy sources. The end products of glucose degradation were lactate, formate, ethanol, acetate, H(2), and CO(2). The predominant cellular fatty acids were non-branched fatty acids C(16:1), C(16:0), and C(14:0). The G + C mole% of the DNA was 32.7%. Phylogenetic analysis based on the 16S rRNA gene sequence revealed that strain S200(T) formed a distinct lineage within the family Halobacteroidaceae, order Halanaerobiales, and was most closely related to Halanaerobaculum tunisiense DSM 19997(T) and Halobacteroides halobius DSM 5150(T), with sequence similarity of 92.3 and 91.9%, respectively. On the basis of its physiological and genotypic properties, strain S200(T) is proposed to be assigned to a novel species of a novel genus, for which the name Halanaerocella petrolearia is proposed. The type strain of Halanaerocella petrolearia is strain S200(T) (=DSM 22693(T) = JCM 16358(T)).