Indexed on: 11 Jul '13Published on: 11 Jul '13Published in: International journal of systematic and evolutionary microbiology
A facultatively anaerobic, alkaliphilic, Gram-stain-positive, rod-shaped bacterium, designated strain 12/1(T), isolated from alkaline wastewater drained sludge of a beverage industry facility located near New Delhi, India, was subjected to a polyphasic taxonomic study. Phylogenetic analysis based on 16S rRNA gene sequence comparisons revealed that strain 12/1(T) belonged to the genus Exiguobacterium and was most closely related to Exiguobacterium aurantiacum DSM 6208(T) (99.46 %), E. aquaticum IMTB-3094(T) (99.18 %), E. mexicanum 8N(T) (99.06 %), E. profundum 10C(T) (98.17 %), E. aestuarii TF-16(T) (98.1 %) and E. marinum TF-80(T) (98.03 %). The DNA G+C content of strain 12/1(T) was 55.6 mol%, major respiratory isoprenoid quinone was MK-7, major polar lipids were phosphatidylglycerol, diphosphatidylglycerol and phosphatidylethanolamine and the cell-wall peptidoglycan was of the A3α l-Lys-Gly type, characteristics consistent with its affiliation to the genus Exiguobacterium. Strain 12/1(T) showed levels of DNA-DNA hybridization of less than 70 % with the closely related species of the genus Exiguobacterium. Overall, the phenotypic, chemotaxonomic and phylogenetic data presented in this study suggest that strain 12/1(T) represents a novel species of the genus Exiguobacterium, for which the name Exiguobacterium alkaliphilum sp. nov. is proposed. The type strain is 12/1(T) ( = CCM 8459(T) = DSM 21148(T)).