Aurantibacillus circumpalustris gen. nov., sp. nov., the first characterized representative of the Bacteroidota candidate family env.OPS 17 and proposal of Aurantibacillaceae fam. nov.

Abstract

16S rRNA sequence types associated with the candidate family env.OPS 17 have been reported from various environments, but no representatives have been characterized and validly named. Bacteria of env.OPS 17 are affiliated with the order Sphingobacteriales and were first detected more than two decades ago in the vicinity of a thermal spring in Yellowstone National Park. Strain Swamp196T, isolated from the soil surrounding a swamp in Northern Germany, is the first characterized representative of candidate family env.OPS 17. Cells of strain Swamp196T are rod-shaped, non-motile, non-spore-forming, non-capsulated and stain Gram-negative. Colonies are small and orange-coloured. The strain is mesophilic and grows under aerobic or microaerophilic conditions. It grows chemo-organotrophically over a narrow range of pH and exclusively on proteinaceous substrates. The major cellular fatty acids are iso-C15 : 0, iso-C15 : 1  ω10c, C18 : 1  ω9c and C16 : 1  ω7c and the major polar lipids are two unidentified aminophospholipids, one unidentified aminolipid and one unidentified lipid. The predominant respiratory quinone is MK-7. The DNA G+C content of genomic DNA is 35.5 mol%. Strain Swamp196T is related to Pedobacter cryophilus AR-3-17T, Arcticibacter pallidicorallinus Hh36T and Pedobacter daechungensis Dae 13T with 16S rRNA gene sequence similarity of 84.1, 83.8 and 83.5 %, respectively. Based on our phenotypic, genomic and phylogenetic analysis, we propose the novel species Aurantibacillus circumpalustris sp. nov (type strain Swamp196T=DSM 105849T=CECT 30420T) of the novel genus Aurantibacillus gen. nov. and the novel family Aurantibacillaceae fam. nov.