Bacillus arsenicus sp. nov., an arsenic-resistant bacterium isolated from a siderite concretion in West Bengal, India.

Strain Con a/3(T) is a Gram-positive, motile, endospore-forming, rod-shaped and arsenic-resistant bacterium, which was isolated from a concretion of arsenic ore obtained from a bore-hole. The bacterium grew in the presence of 20 mM arsenate and 0.5 mM arsenite. Diaminopimelic acid was present in the cell wall peptidoglycan, MK-7 was the major menaquinone, and iso-C(15 : 0), anteiso-C(15 : 0), iso-C(16 : 0) and C(16 : 1)(delta7cis) were the major fatty acids. Based on its phenotypic, chemotaxonomic and phylogenetic characteristics, strain Con a/3(T) was identified as a member of the genus Bacillus. It exhibited maximum similarity (97 %) at the 16S rRNA gene level with Bacillus barbaricus (DSM 14730(T)); however, the DNA-DNA relatedness value with B. barbaricus was 60 %. Strain Con a/3(T) also exhibited a number of phenotypic differences from B. barbaricus (DSM 14730(T)). Strain Con a/3(T) was therefore identified as representing a novel species of the genus Bacillus, for which the name Bacillus arsenicus sp. nov. is proposed. The type strain is Con a/3(T) (= MTCC 4380(T) = DSM 15822(T) = JCM 12167(T)).