Acidithrix ferrooxidans

Type strain Py-F3 was isolated from acidic, metal-rich mine waters in North Wales.[5] Py-3 can grow different metabolisms for potential growth substrates,[4] and can grow at a range of temperatures from 10 to 30°C and pH from1.5-4.4.[4][7] Strain Py-F3 encodes multiple enzymes for carbon fixation, including RubisCO, but its carbon fixation activity has not been studied.[4] Genes encoding proteins for metabolic pathways utilizing sulfur, nitrogen, and iron were discovered in the genome.[4] The source of sulfur is sulfate, and it can use amino acids as a nitrogen source. This is unique requirement of isolate Py-F3, leaving it with an inability to grow in media unless complex substrates are added.[4] For pH homeostasis the urease genes could aid survival due to encoded the proton pumping activity.[4][7] Uptake of urea is documented in Py-F3 and allows for the intracellular production of urea, rather than taking it in to the cell.[4] This organism's peptidoglycan contains meso-dia-minopimelic acid and with major fatty acid chains and a respiratory quinone.[7]

Isolate C25 was recovered from particulate iron forming in a pelagic iron-rich redoxcline zone of a mine lake.[5] This isolate can both oxidize Fe(II) and reduce Fe(III) under micro-oxic conditions, and was suggested to contribute to the formation of particulate iron in the pelagic environment.[5] Growth did not occur at pH lower than that of Py-F3 (pH) of 2, while C25 had a higher pH tolerance.[5] The observation that C25 can both oxidize and reduce iron provides insights into how microbes cycle both iron and organic carbon under acidic conditions.[5] Fast rates of iron oxidation lead to the regeneration of ferric iron in the environment at a pH as low as 1.5.[8][6] Compared to Py-F3, C25 did not encode for the ribulose, but future studies will need to be done for a definitive answer.[5]