Haloanaerobium salsugo sp. nov., a moderately halophilic, anaerobic bacterium from a subterranean brine

A strictly anaerobic, moderately halophilic, gram-negative bacterium was isolated from a highly saline oil field brine. The bacterium was a non- spore-forming, nonmotile rod, appearing singly, in pairs, or occasionally as long chains, and measured 0.3 to 0.4 by 2.6 to 4 μm. The bacterium had a specific requirement for NaCl and grew at NaCl concentrations of between 6 and 24%, with optimal growth at 9% NaCl. The isolate grew at temperatures of between 22 and 51°C and pH values of between 5.6 and 8.0. The doubling time in a complex medium containing 10% NaCl was 9 h. Growth was inhibited by chloramphenicol, tetracycline, and penicillin but not by cycloheximide or azide. Fermentable substrates were predominantly carbohydrates. The end products of glucose fermentation were acetate, ethanol, CO₂, and H₂. The major components of the cellular fatty acids were C(14:0), C(16:0), C(16:1), and C(17:0 cyc) acids. The DNA base composition of the isolate was 34 mol% G+C. Oligonucleotide catalog and sequence analyses of the 16S rRNA showed that strain VS-752(T) was most closely related to Haloanaerobium praevalens GSL(T) (ATCC 33744), the sole member of the genus Haloanaerobium. We propose that strain VS-752 (ATCC 51327) be established as the type strain of a new species, Haloanaerobium salsugo, in the genus Haloanaerobium.