Deinococcus indicus sp. nov., an arsenic-resistant bacterium from an aquifer in West Bengal, India

Abstract

An arsenic- and radiation-resistant bacterium, strain Wt/1aT, was isolated from water from an arsenic-contaminated aquifer located in the Chakdah district of West Bengal, India. The bacterium stains Gram-negative and is rod-shaped, non-motile, non-sporulating and red-pigmented. Cell-wall peptidoglycan contains ornithine as the diamino acid, MK-8 is the major menaquinone, C15 : 1 and C16 : 1 are the major fatty acids and the DNA G+C content of the organism is 65·8 mol%. Based on these phenotypic and chemotaxonomic characteristics, strain Wt/1aT was identified as a member of the genus Deinococcus. Strain Wt/1aT exhibited maximum 16S rRNA gene sequence similarity (95 %) with Deinococcus grandis; however, strain Wt/1aT exhibited only 14 % similarity to D. grandis IAM 13005T at the DNA–DNA level. Furthermore, strain Wt/1aT (compared to D. grandis IAM 13005T) is more resistant to arsenate and arsenite, is positive for arginine dihydrolase, utilizes a number of carbon sources and exhibits quantitative differences in fatty acid composition and qualitative differences in lipid composition. Strain Wt/1aT is identified as a novel species of the genus Deinococcus, for which the name Deinococcus indicus sp. nov. is proposed. The type strain of Deinococcus indicus is Wt/1aT (=MTCC 4913T=DSM 15307T).