Bacillus marismortui sp. nov., a new moderately halophilic species from the Dead Sea

1 Departamento de Microbiologia y Parasitologia, Facultad de Farmacia, Universidad de Sevilla, Seville, Spain 2 Marine Biology Research Division, Scripps Institution of Oceanography, University of California, San Diego, La Jolla, CA, USA, 3 Lehrstuhl for Mikrobiologie, Technische Universitat Monchen, Munich, Germany Author for correspondence: Antonio Ventosa. Tel: +34 954 556 765. Fax: +34 954 628 162. e-mail: ventosa{at}cica.es ABSTRACT A group of 91 moderately halophilic, Gram-positive, rod-shaped strains were isolated from enrichments prepared from Dead Sea water samples collected 57 years ago. These strains were examined for 117 morphological, physiological, biochemical, nutritional and antibiotic susceptibility characteristics. All strains formed endospores and were motile, strictly aerobic and positive for catalase and oxidase. They grew in media containing 5-25% (w/v) total salts, showing optimal growth at 10% (w/v). Eighteen strains were chosen as representative isolates and were studied in more detail. All these strains had meso- diaminopimelic acid in the cell wall and a DNA G+C content of 39·0-42·8 mol%; they constitute a group with levels of DNA-DNA similarity of 70-100%. The sequences of the 16S rRNA genes of three representative strains (strains 123 T , 557 and 832) were almost identical (99·9%), and placed the strains in the low G+C content Gram-positive bacteria. On the basis of their features, these isolates should be regarded as members of a new species of the genus Bacillus , for which the name Bacillus marismortui sp. nov. is proposed. The type strain is strain 123 T (= DSM 12325 T = ATCC 700626 T =CIP 105609 T =CECT 5066 T ). Key Words: Bacillus marismortui • taxonomy • DNA-DNA similarity • cell wall type • 16S rRNA sequence Deceased 6 February 1999. The EMBL accession number for the 16S rRNA gene sequence of strain 123 T is AJ009793 .