Transfer of Clostridium lortetii to a New Genus Sporohalobacter gen. nov. as Sporohalobacter lortetii comb. nov., and Description of Sporohalobacter marismortui sp. nov.

We propose to create a new genus of anaerobic halophilic sporeforming bacteria, Sporohalobacter gen. nov., to harbor the former species Clostridium lortetii as Sporohalobacter lortetii comb. nov.. Its previous assignment to the genus Clostridium is not justified because of its Gram-negative type cell wall, and because of its phylogenetic position, supporting its membership to the family Haloanaerobiaceae. We here describe a second species of this genus, Sporohalobacter marismortui sp. nov., an anaerobic, rod-shaped, motile, Gram-negative, sporulating bacterium isolated from sediments on the shore of the Dead Sea. It required NaCl concentrations between 0.5 and 3 M, and optimal growth with doubling times of about 40 min was found in 0.5–2.0 M NaCl and at 36–45°C. Fermentation products on glucose were ethanol, acetate, butyrate, formate, hydrogen and carbon dioxide. Fermentable substrates included several mono-and disaccharides, starch and glycogen. The G+C content of its DNA was 29.6 mol%. Analysis of the oligonucleotides in a T1 RNAse digest of its 16S ribosomal RNA showed the isolate to be related to Sporohalobacter (Clostridium) lortetii and other representatives of the family Haloanaerobiaceae. The type strain is strain DY-1, ATCC 35420.