Halobacillus alkaliphilus sp. nov., a halophilic bacterium isolated from a salt lake in Fuente de Piedra, southern Spain Ida Romano, 1 Ilaria Finore, 1 Giancarlo Nicolaus, 2 F. Javier Huertas, 3 Licia Lama, 1 Barbara Nicolaus 1 and Annarita Poli 1 Correspondence Annarita Poli apoli@icmib.na.cnr.it 1 Istituto di Chimica Biomolecolare, Comprensorio ex Olivetti, via Campi Flegrei 34, 80078 Pozzuoli, Napoli, Italy 2 Istituto di Ricerche di Biologia Molecolare, IRBM, Pomezia, Italy 3 CSIC, Estacion Experimental del Zaidin, Department of Earth Sciences and Environmental Chemistry, Profesor Albareda 1, 18008 Granada, Spain A Gram-positive, spore-forming, halophilic bacterial strain, FP5 T , was isolated from a salt lake in southern Spain and subjected to a polyphasic taxonomic study. Strain FP5 T was strictly aerobic. Cells were coccoidal, occurring singly or in clusters. The cell-wall peptidoglycan type of strain FP5 T was A4b based on L-Orn–D-Asp. Strain FP5 T was characterized chemotaxonomically by having MK-7 as the major menaquinone and anteiso-C 15 : 0 , anteiso-C 17 : 0 , iso-C 15 : 0 and iso-C 16 : 0 as the main fatty acids. The isolate grew optimally at 37 6C and in presence of 10 % NaCl; no growth was observed in the absence of NaCl. The DNA G+C content was 43.5 mol%. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain FP5 T falls within the evolutionary radiation of species of the genus Halobacillus. Levels of 16S rRNA gene sequence similarity between strain FP5 T and the type strains of nine recognized Halobacillus species were in the range 97.0–99.0 %. Levels of DNA–DNA relatedness indicated that strain FP5 T represents a genomic species that is distinct from recognized Halobacillus species. Strain FP5 T could be differentiated from recognized Halobacillus species based on several phenotypic characteristics. On the basis of phenotypic, phylogenetic and genomic data, strain FP5 T is considered to represent a novel species of the genus Halobacillus, for which the name Halobacillus alkaliphilus sp. nov. is proposed. The type strain is FP5 T (5DSM 18525 T 5ATCC BAA-1361 T ). The genus Halobacillus was first described by Spring et al. (1996) to accommodate two novel species, Halobacillus litoralis and Halobacillus trueperi, and the transfer of Sporosarcina halophila (Claus et al., 1983) to Halobacillus as Halobacillus halophilus. At the time of writing, the genus comprises 13 species with validly published names, with the addition of Halobacillus salinus (Yoon et al., 2003), H. karajensis (Amoozegar et al., 2003), H. locisalis (Yoon et al., 2004), H. yeomjeoni (Yoon et al., 2005), H. dabanensis and H. aidingensis (Liu et al., 2005), H. profundi and H. kuroshimensis (Hua et al., 2007), H. campisalis (Yoon et al., 2007) and H. faecis (An et al., 2007). The genus Halobacillus can be differentiated clearly from other related genera based on the cell-wall peptidoglycan type based on L-Orn–D-Asp (Spring et al., 1996; Shida et al., 1997; Yoon et al., 2001), with the exception of that for H. campisalis, which is based on meso-diaminopimelic acid (Yoon et al., 2007). The aim of the present study was to determine the exact taxonomic status of a halophilic bacterial strain, FP5 T , by using a polyphasic approach, including phenotypic properties, lipid analyses, phylogen- etic analysis based on 16S rRNA gene sequences and levels of genotypic relatedness. Strain FP5 T was isolated from samples collected during summer 2005 from Fuente de Piedra saline lake, Malaga province, southern Spain (37 u 69 N4 u 449 W). It was isolated from a saltern crystallizer pond by the dilution- plating technique. Strain FP5 T represented the predom- inant organism in the enrichment and was the only colony- forming organism at the highest dilutions. The enrichment medium (medium A) contained the following components The GenBank/EMBL/DDBJ accession number for the 16S rRNA gene sequence of strain FP5 T is AM295006. A scanning electron micrograph of cells of strain FP5 T and thin-layer chromatographs of total polar lipids of strain FP5 T are available as supplementary material with the online version of this paper. International Journal of Systematic and Evolutionary Microbiology (2008), 58, 886–890 DOI 10.1099/ijs.0.65457-0 886 65457 G 2008 IUMS Printed in Great Britain