Thiobacillus ferrooxidans is a gram negative, obligately autotrophic and aerobic Proteobacteria. These bacteria are motile, and possess polar flagella. T. ferrooxidans is an acidophile, living in environments with an optimal pH range of 1.5 to 2.5. T. ferrooxidans is also thermophilic, preferring temperatures of 45 to 50 degrees Celsius. The high temperature tolerance of the bacteria may be due in part to its high GC content of 55 to 65 mole percent.