Multiple pathways for aerobic and arsenate respiration of Melioribacter roseus, a metabolically versatile bacterium representing of Ignavibacteriae phylum

Melioribacter roseus is one of two cultured representatives of the phylum Ignavibacteriae. It could grow by fermentation of sugars and peptides, by aerobic respiration or by dissimilatory reduction of arsenate, nitrite or Fe(III) on fermentable and non-fermentable substrates, what allows this bacterium to adapt to fluctuating environmental conditions. Primary genome analysis highlighted key determinants of electron transport chains, providing important insights into the ability of M. roseus to use a range of electron acceptors. Complete set of genes for proton-translocating membrane complexes I and II, alternative complex III (ACIII) and seven terminal oxidoreductases was found in the M. roseus genome. Among those three different cytochrome oxidases and two different molybdopterin oxidoreductases have been proposed to determine two most active respiratory processes performed by M. roseus – aerobic respiration and dissimilatory arsenate reduction, respectively.