gen. nov., sp. nov., a Novel Anaerobic Free-Living Mollicute Isolated from a Terrestrial Mud Volcano.

A novel aerotolerant anaerobic bacterium (strain M4Ah) was isolated from a terrestrial mud volcano (Taman Peninsula, Russia). Cells were small, cell-wall-less, non-motile cocci, 0.32-0.65 μm in diameter. The isolate was a mesophilic, neutrophilic chemoorganoheterotroph, growing on carbohydrates (D-glucose, D-trehalose, D-ribose, D-mannose, D-xylose, D-maltose, D-lactose, D-cellobiose, D-galactose, D-fructose, and D-sucrose), proteinaceous compounds (yeast extract, tryptone), and pyruvate. Strain M4Ah tolerated 2% oxygen in the gas phase, was catalase-positive, and showed sustainable growth under microaerobic conditions. The dominant cellular fatty acids of strain M4Ah were C and C. The G+C content of the genomic DNA was 32.42%. The closest phylogenetic relative of strain M4Ah was from the family (order , class ). Based on the polyphasic characterization of the isolate, strain M4Ah is considered to represent a novel species of a new genus, for which the name gen. nov., sp. nov. is proposed. The type strain of is M4Ah (=DSM 112561 = VKM B-3485 = UQM 41475). This is the first representative of the order , isolated from a mud volcano.