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 BNO1^T 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 BNO1^T is 5,347,902 bp, 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-C_15:0 (23.34%), iso-C_15:0 (20.10%), C_16:0 (11.96%), iso-C_16:0 (10.88%), and anteiso-C_17:0 (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 BNO1^T and other related strains to new species and to name it Cytobacillus pseudoceanisediminis sp. nov. (The values of ANI and dDDH between BNO1^T and Cytobacillus oceanisediminis CGMCC 1.10115 ^T are 80.65% and 24.7%, respectively; values of ANI and dDDH between BNO1^T and Cytobacillus firmus NCTC 10335 ^T are 89% and 38%, respectively). Genomic analysis of strain BNO1^T revealed pathways for C1 compounds oxidation and two pathways for C1 compounds assimilation: serine and ribulose monophosphate pathways. In addition, strain BNO1^T contains a plasmid (342,541 bp) coding multiple genes involved in heavy metal ion balance. Moreover, heavy metal toxicity testing confirmed the high potential of the strain BNO1^T as a source of metal resistance genes and enzymes. The type strain is BNO1^T (= BIM B-1921 ^T = VKM B-3664 ^T).