Cytobacillus pseudoceanisediminis sp. nov., A Novel Facultative Methylotrophic Bacterium with High Heavy Metal Resistance Isolated from the Deep Underground Saline Spring

Abstract

In this study, we present the characterization of the BNO1T bacterial strain isolated from the deep subsurface saline spring at the Baksan Neutrino Observatory INR RAS (Kabardino-Balkaria, Russia). The complete genome sequence of the strain BNO1T is 5,347,902bp, with a GC content 41 and 49%. The cell wall peptidoglycan contains meso-diaminopimelic acid. The major isoprenoid quinone is MK-7 and the polar lipids are diphosphatidylglycerol, phosphatidylglycerol, and phosphatidylethanolamine. The major fatty acids are anteiso-C15:0 (23.34%), iso-C15:0 (20.10%), C16:0 (11.96%), iso-C16:0 (10.88%), and anteiso-C17:0 (10.79%). The 16S rRNA gene sequence clearly demarcated the strain as belonging to Cytobacillus genera. Based on the phylogenetic analysis, ANI (average nucleotide identity) and dDDH (digital DNA-DNA hybridization) assessments we propose to assign the strain BNO1T and other related strains to new species and to name it Cytobacillus pseudoceanisediminis sp. nov. (The values of ANI and dDDH between BNO1T and Cytobacillus oceanisediminis CGMCC 1.10115T are 80.65% and 24.7%, respectively; values of ANI and dDDH between BNO1T and Cytobacillus firmus NCTC 10335T are 89% and 38%, respectively). Genomic analysis of strain BNO1T revealed pathways for C1 compounds oxidation and two pathways for C1 compounds assimilation: serine and ribulose monophosphate pathways. In addition, strain BNO1T contains a plasmid (342,541bp) coding multiple genes involved in heavy metal ion balance. Moreover, heavy metal toxicity testing confirmed the high potential of the strain BNO1T as a source of metal resistance genes and enzymes. The type strain is BNO1T (= BIM B-1921T = VKM B-3664T).