Persephonella hydrogeniphila sp nov., a novel thermophilic, hydrogen-oxidizing bacterium from a deep-sea hydrothermal vent chimney

A novel thermophilic, hydrogen-oxidizing bacterium, designated 29W(T), was isolated from a deep-sea hydrothermal vent chimney sample collected from the Suiyo Seamount in the Izu-Bonin Arc, Japan, at a depth of 1385 m. The cells were cocci (0.9-1.0 mum in diameter) and straight rods (2.3-2.7 mum long) under static and agitated culture conditions, respectively. The new isolate was an obligate chemolithoautotroph growing by respiratory nitrate reduction with H-2, forming N-2 as a final product. A very low concentration Of 02 (Optimum 0.6-0.8 %, v/v) was also used as an alternative electron acceptor while reduced sulfur compounds did not serve as electron donors. Anoxic hydrogen-oxidizing growth with nitrate was observed between 50 and 72.5degreesC (optimum 70degreesC; 40 min doubling time), pH 5.5 and 7.6 (optimum pH 7.2), and in the presence of 1.5 and 5.0 % NaCl (optimum 2.5 %). The G + C content of the genomic DNA was 37.3 mol%. Phylogenetic analysis based on 16S rDNA sequences indicated that the isolate was a member of the recently described genus Perspehonella in a potential new family within the order Aquificales. On the basis of the physiological and molecular properties of the new isolate, the name Persephonella hydrogeniphila sp. nov. is proposed. The type strain is strain 29WT (=JCM 11663(T) = DSM 15103(T)).