Characterization of two novel chemolithoautotrophic bacteria of Sulfurovum from marine coastal environments and further comparative genomic analyses revealed species differentiation among deep-sea hydrothermal vent and non-vent origins

Bacteria of the genus Sulfurovum within class Campylobacteria are widespread in global oceans and predominant sulfide-rich environments. However, little is known about their adaptation to such harsh environments owing resistance cultivation. In this study, we obtained three pure cultures from marine coastal compared them with those deep sea. Phylogenetic analysis 16S rRNA gene sequences indicated that they represent two novel species genus, sharing 95.9%–96.1% sequence similarities aggregans Monchim33 T . Based on polyphasic classification results, type strains XTW-4 zt1-1 were proposed new species: xiamenensis sp. nov. zhangzhouensis nov., respectively. These isolates also obligate chemoautotrophs featuring molecular hydrogen as an electron donor oxygen, thiosulfate, or elemental sulfur sole acceptor. Comparative genomic analyses based 11 further revealed a clear differentiation between hydrothermal vent non-vent origins. The can use thiosulfate acceptor but lacks denitrification pathways, whereas bacteria respire nitrate through complete pathways. Moreover, contained nitrogen fixation pathway, implying source-deficit niches. addition, adapted higher oxygen concentration via multiple antioxidative defense mechanisms. phenotypic genotypic features help us understand ecological role ecosystems.