Acidiphilium cryptum gen. nov., sp. nov., Heterotrophic Bacterium From Acidic Mineral Environments Harrison, Arthur P.,, 31, 327-332 (1981), doi = https://doi.org/10.1099/00207713-31-3-327, publicationName = Microbiology Society, issn = 1466-5026, abstract= Abstract Acidiphilium gen. nov. is comprised of gram-negative, aerobic, mesophilic, rodshaped bacteria that grow in lean organic media between pH 1.9 and 5.9 but not at pH 6.1. Small amounts of organic substrates are required for growth, but high concentrations inhibit growth, especially the organic digests used in conventional bacteriological media. Sodium acetate is strongly inhibitory at a concentration of 0.01%. Endospores are not formed, and some strains are motile by means of one polar flagellum or two lateral flagella. The guanine-plus-cytosine content of the deoxyribonucleic acid varies between 68 and 70 mol%. Some catalase is formed, but the oxidase reaction is very weak or absent. This genus differs from Pseudomonas, Chromobacterium, Flavobacterium, and other soil heterotrophs by its requirement for a high concentration of hydrogen ions and its sensitivity to many organic substrates. It differs from Pseudomonas also by its lack of a strong oxidase reaction and especially by its inhibition by acetate. It is easily distinguished from acidophilic thiobacilli by its inability to utilize sulfur and ferrous iron as sources of energy and by the high guanine-plus-cytosine content of deoxyribonucleic acid. The type species is Acidiphilium cryptum, and the type strain of this species is strain Lhet2 (=ATCC 33463)., language=, type=