Sporosarcina halophila sp. nov., an Obligate, Slightly Halophilic Bacterium from Salt Marsh Soils

Abstract

Twenty-two strains of endospore-forming sarcinae have been isolated from salt marsh soils. The isolates differ phenotypically from Sporosarcina ureae, the only species of the genus Sporosarcina which has been validly described, and are distinct from S. ureae in the composition of the cell walls of their vegetative cells. Lysine, found in the tetrapeptide of the murein of S. ureae, is replaced by ornithine in the new isolates. The interpeptide bridge consists of an aspartic acid residue instead of D-glutamylglycine as is found in S. ureae. The mol% G + C of the DNA of the new isolates is in the range of 40.1-40.9 (S. ureae 40.0-41.5). DNA hybridization studies revealed a high DNA-DNA homology within the new isolates but only a low relationship to S. ureae. The main menaquinone is of the MK-7 type as in S. ureae and other aerobic sporeformers. The spores of the new isolates are very similar to spores of S. ureae and Bacillus species in respect of their heat resistance, composition and ultrastructure. None of the new isolates grows on complex media unless supplemented with sodium, magnesium and chloride ions. Strains are slight halophiles as they grow best in the presence of 30 to 50 g NaCl/1 and 5 g MgCl(2)/l. The new isolates thus belong to a new species, for which the name Sporosarcina halophila is proposed. Strain DSM 2266 (= strain 3) is the type strain.