Fictibacillus halophilus sp. nov., from a microbial mat of a hot spring atop the Himalayan Range

Abstract

A Gram-stain-positive staining, motile, endospore forming and moderately halophilic bacterium, designated as strain AS8T, was isolated from a microbial mat deposited at thermal discharges of Manikaran hot spring (with surface water temperature ~95 °C) located in Himachal Pradesh, India. 16S rRNA gene sequence based phylogenetic analysis revealed that strain AS8T belonged to the genus Fictibacillus with the highest sequence similarity to Fictibacillus nanhaiensis DSM 23009T (99.9 %) and Fictibacillus phosphorivorans Ca7T (99.9 %), followed by Fictibacillus barbaricus V2-BIII-A2T (99.1 %) and Fictibacillus arsenicus Con a/3T (97.4 %). The polar lipids fraction consisted of diphosphatidylglycerol, phosphatidylglycerol and phosphatidylethanolamine. The cell-wall peptidoglycan was of the type A1γ based on directly cross-linked meso-diaminopimelic acid. The DNA G+C content of strain AS8T was found to be 46.9 mol%. The quinone system of strain AS8T consisted of MK-7 predominantly, and the polyamine pattern primarily contained spermidine and spermine. The major cellular fatty acids in strain AS8T were iso-C15:0, anteiso-C15:0 and iso-C16:0. The strain showed DNA-DNA relatedness of 52.7 % with F. nanhaiensis DSM 23009T, 50.7 % with F. phosphorivorans Ca7T, 34.8 % with F. barbaricus V2-BIII-A2T and 38.0 % with F. arsenicus Con a/3T. In spite of the high 16S rRNA gene sequence similarities, the DNA-DNA hybridization and gyr B gene sequencing results (≤87 %) supported by physiological and biochemical tests demonstrated that strain AS8T is a representative of a novel species, for which the name Fictibacillus halophilus sp. nov. is proposed. The type strain is AS8T (=MCC 2765T=DSM 100124T=KCTC 33758T).