Acidisphaera is a genus in the phylum Proteobacteria (Bacteria). The genus contains a single species, namely A. rubrifaciens with the following characteristics: * strictly aerobic, light preferred * mesophilic * acidophilic (3.5–6.0 pH, optima of 4.5-5.0) * bacteriochlorophyll (BChl a) and carotenoids production (salmon-pink colonies), the former contained zinc if grown in the presence of 1 mM zinc sulfate. * chemo-organotrophic * Gram-negative, as expected from a proteobacterium * isolated from acidic hot springs and mine drainage * non-motile * cocci / coccobacilli * Part of the major acidophilic alphaproteobacterial group with the genera Acidiphilium and Rhodopila