THIOBACILLUS-PLUMBOPHILUS SPEC NOV, A NOVEL GALENA AND HYDROGEN OXIDIZER

From an uranium mine three strains of rod-shaped, mesophilic, chemolithoautotrophic bacteria were isolated. They grow by oxidation of H2S, galena (PbS) and H-2. Anglesite (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).