Microvirga subterranea gen. nov., sp nov., a moderate thermophile from a deep subsurface Australian thermal aquifer

A strictly aerobic bacterium, strain Fai14(T), Was isolated from free-flowing geothermal waters of a bore (bore register no. 3768) tapping the Great Artesian Basin of Australia. The non-sporulating, Gram-negative cells of strain Fai14(T) produced light-pink colonies, were rod-shaped (11 x 1.5-4 mum) and were motile by a single polar flagellum. Strain Fai14(T) grew optimally at 41 degreesC at a pH of 7.0 and had an absolute requirement for yeast extract. The strain grew on casein hydrolysate, tryptone, gelatin, xylose and acetate in a medium supplemented with 0.06 or 0.006% yeast extract. Weak acid production was detected from glucose and arabinose. Catalase was produced. Nitrite was produced from nitrate. Strain Fai14 (T) was sensitive to antibiotics that inhibit growth of bacteria. The G + C content was 63.5 + 0.5 mol%. Strain Fai14(T) was a member of the class 'Alphaproteobacteria', phylum Proteobacteria, placed almost equidistantly between Methylobacterium species, Chelatococcus asaccharovorans and Bosea thiooxidans (similarity value of 93%) as its nearest phylogenetic relatives. Phylogenetic and phenotypic evidence suggest that strain Fai14(T) (=ATCC BAA-295(T) = DSM 14364(T)) should be placed as the type strain of a species in a newly created genus, for which the name Microvirga subterranea gen. nov., sp. nov. is proposed.