抄録
A novel moderately thermophilic iron-oxidizing bacterium was isolated from a coal dump in Iizuka City, Japan, and designated strain TI-1. Strain TI-1 was a Gram negative, non-spore-forming, and rod-shaped bacterium, which had a optimum temperature and pH for growth at 48°C and 2.2, respectively. The mean G + C content of the DNA was 56.2mol%. Strain TI-1 required yeast extract for growth and did not have the ability to fix carbon dioxide as a carbon source, indicating that the strain is not chemolithoautotroph. When grown on Fe2+ (1.7%)-yeast extract medium, Fe2+ was oxidized concomitantly with cell growth. The optimum pH and temperature for Fe2+ oxidation by washed intact cells of TI-1 were 2.8 and 50°C, respectively. The properties of strain TI-1 shown above, such as the G + C mol content of the DNA, the requirement of yeast extract for growth, and the inability to fix carbon dioxide, suggest that strain TI-1 belongs to a new type of mederately thermophilic, acidophilic iron-oxidizing bacterium.
