Isolation and characterization of acidophilic bacterium from Gaofeng Mine in China

An acidophilic, chemolithotrophic and ferrous oxidizing bacterium strain GF was isolated from the acid mine drainage (AMD) of Gaofeng Mine, Guangxi Province, China using 9K enrichment medium, and then purified on solid ferrous-agarose medium. The physiological experiments show that it can use ferrous or sulfur as sole energy and a low level (0.1%, w/v) of peptone can accelerate the growth of the isolated strain. The optimum pH and temperature for growth are 2.0 and 30 °C, respectively. The isolated strain shares 99.64% identities of 16S rRNA gene with the type strain Acidthiobacillus ferrooxidans ATCC 23270 and 100% identities of iro gene (CDS) with A. ferrooxidans strain Fe-1. These results show that the strain can be considered as Acidthiobacillus ferrooxidans. Because of the high activity of oxidizing ferrous and sulfide mineral, strain GF was used in bioleaching of marmatite. The Zn concentration is 0.273 g/L under the steriled control and 7.30 g/L with adapted GF strain incubated after 29 d in leaching marmatite. The isolated strain GF can be used to leach marmatite in industry application.