The ecology and taxonomy of anaerobic halophilic eubacteria

Abstract A number of obligately anaerobic chemoorganotrophic moderately halophilic bacteria have been isolated from the bottom sediments of the Dead Sea and the Great Salt Lake, Utah: (1) Halobacteroides halobius , a long motile rod from the Dead Sea, fermenting sugars to ethanol, acetate, H₂ and CO₂; (2) Clostridium lortetii , a rod-shaped bacterium from the Dead Sea, producing endospores with attached gas vacuoles; (3) a spore-forming motile rod-shaped bacterium, fermenting sugars, isolated from the Dead Sea; (4) Haloanaerobium praevalens , isolated from the Great Salt Lake, fermenting carbohydrates, peptides, amino acids and pectin to acetate, propionate, butyrate, H₂ and CO₂.
Analysis of their 16S rRNA shows that these organisms are related to each other, but unrelated to any of the other subgroups of the eubacterial kingdom, to which they belong.
Ha. praevalens and Hb. halobius regulate their internal osmotic pressure by the accumulation of salt (Na⁺, K⁺, Cl^?) rather than by organic osmotic solutes.