Halobacterium sodomense sp. nov., a Dead Sea Halobacterium with an Extremely High Magnesium Requirement

Abstract

A strain of Halobacterium was isolated from the Dead Sea. This isolate differs from the previously isolated halobacteria in (i) its requirement for sodium ions, which is lower than that of most other halobacteria (≥0.5 M), (ii) its requirement for divalent cations (Mg2+ or Ca2+), which is higher than that of most other halobacteria (optimal growth was obtained in the presence of 0.6 to 1.2 M Mg2+), (iii) its requirement for either starch or clay minerals (bentonite) for growth in the standard growth medium used, and (iv) its synthesis of purple membrane at low oxygen tensions in the light. This organism has been designated Halobacterium sodomense sp. nov. The type strain is strain ATCC 33755.