Unusual Genomic and Biochemical Features of sp. nov-A Novel Bacterial Species Isolated from Anthill Soil.

The black garden ant () is a widely distributed species across Europe, North America, and North Africa, playing a pivotal role in ecological processes within its diverse habitats. However, the microbiome associated with remains poorly investigated. In the present study, we isolated a novel species, , from the soil of the anthill. The genome of S21 was sequenced, annotated, and searched for groups of genes of physiological, medical, and biotechnological importance. Subsequently, a series of microbiological, physiological, and biochemical experiments were conducted to characterize S21 with respect to its sugar metabolism, antibiotic resistance profile, lipidome, and capacity for atmospheric nitrogen fixation, among others. A notable feature of the S21 genome is the presence of two prophages, which may have horizontally transferred host genes involved in stress responses. S21 synthesizes a number of lipids, including mono- and digalactosyldiacylglycerol, as well as steroid compounds that are typically found in eukaryotic organisms rather than prokaryotes. S21 exhibits resistance to penicillins, lincosamides, fusidins, and oxazolidinones, despite the absence of specific genes conferring resistance to these antibiotics. Genomic data and physiological tests indicate that S21 is nonpathogenic to humans. The genome of S21 contains multiple operons involved in heavy metal metabolism and organic compound inactivation. Consequently, represents a novel species with an intriguing evolutionary history, manifesting in distinctive genomic, metabolomic, and physiological characteristics. This species may have potential applications in the bioaugmentation of contaminated soils.