ABSTRACT: A novel aerotolerant anaerobic bacterium (strain M4AhT) 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 M4AhT tolerated 2% oxygen in the gas phase, was catalase-positive, and showed sustainable growth under microaerobic conditions. The dominant cellular fatty acids of strain M4AhT were C16:0 and C18:0. The G+C content of the genomic DNA was 32.4
