Pelagirhabdus alkalitolerans gen. nov., sp. nov., an alkali-tolerant and thermotolerant bacterium isolated from beach sediment, and reclassification of Amphibacillus fermentum as Pelagirhabdus fermentum comb. nov.

Abstract

Pelagirhabdus alkalitolerans gen. nov., sp. nov., an alkali-tolerant and thermotolerant bacterium isolated from beach sediment, and reclassification of Amphibacillus fermentum as Pelagirhabdus fermentum comb. nov. A novel bacterial strain, designated S5 T , was isolated from Pingaleshwar beach, in India. Cells were Gram-stain-positive, rod-shaped, non-motile and non-endospore-forming. Based on 16S rRNA gene sequence analysis, the strain was identified as belonging to the class Firmibacteria and was related most closely to Amphibacillus fermentum DSM 13869 T (97.6 % sequence similarity). However, it shared only 93.1 % 16S rRNA gene sequence similarity with Amphibacillus xylanus NBRC 15112 T , the type species of the genus, indicating that strain S5 T might not be a member of the genus Amphibacillus. The DNA-DNA relatedness between strain S5 T and Amphibacillus fermentum DSM 13869 T was 39 %. The cell-wall peptidoglycan contained meso-diaminopimelic acid. Polar lipids included diphosphatidylglycerol, phosphatidylglycerol and two phospholipids. Isoprenoid quinones were absent from strain S5 T . Fatty acid analysis revealed that anteiso-C 15 : 0 , C 16 : 0 and iso-C 15 : 0 were the predominant fatty acids present. The results of phylogenetic, chemotaxonomic and biochemical tests allowed the clear differentiation of strain S5 T , which is considered to represent a novel species of a new genus in the family Bacillaceae, for which the name Pelagirhabdus alkalitolerans gen. nov., sp. nov. is proposed. The type strain of Pelagirhabdus alkalitolerans is S5 T (5KCTC 33632 T 5CGMCC 1.15177 T ). Based on the present study, it is also suggested to transfer Amphibacillus fermentum to this new genus, as Pelagirhabdus fermentum comb. nov. The type strain of Pelagirhabdus fermentum is Z-7984 T 5(DSM 13869 T 5UNIQEM 210 T ).