Thiobacillus plumbophilus spec. nov., a novel galena and hydrogen oxidizer

From an uranium mine three strains of rod-shaped, mesophilic, chemolithouautotrophic bacteria were isolated. They grow by oxidation of H2S, galena (PbS) and H2. Angelsite (PbSO4) is formed from galena. No ferrous iron is oxidized by the isolates. They grow between pH 4 and 6.5 at temperatures of about 9 to 41 degrees C (optimum around 27 degrees C). The G + C content of the DNA is around 66 mol %. Based on their ability to oxidize sulfur compounds, the new organisms belong to the genus Thiobacillus. No significant homology with Thiobacillus ferrooxidans and Thiobacillus cuprinus was detected by DNA-DNA hybridization. Therefore the new isolates represent a new species within the genus Thiobacillus. Based on the unusual growth on galena, we name the new species Thiobacillus plumbophilus (type strain Gro7; DSM 6690).