Carbohydrate?dependent sulfur respiration in halo(alkali)philic archaea

Archaea are environmentally ubiquitous on Earth, and their extremophilic metabolically versatile phenotypes make them useful as model systems for astrobiology. Here, we reveal a new functional group of halo(natrono)archaea able to utilize alpha-d-glucans (amylopectin, amylose glycogen), sugars, glycerol electron donors carbon sources sulfur respiration. They facultative anaerobes enriched from hypersaline sediments with either amylopectin, glucose or electron/carbon elemental the terminal acceptor. include 10 strains neutrophilic haloarchaea circum pH-neutral lakes one natronoarchaeon soda-lake sediments. The isolates can grow by fermentation, although addition S0 dimethyl sulfoxide increased growth rate biomass yield (with concomitant decrease in H2). Natronoarchaeal isolate AArc-S grew only respiration, anaerobically thiosulfate acceptor, aerobically. Through genome analysis five representative strains, detected full set enzymes required observed catabolic respiratory phenotypes. These findings provide evidence that sulfur-respiring partake biogeochemical cycling, linked anaerobic mineralization anoxic habitats. We discuss implications life detection analogue environments such polar subglacial brine-lakes Mars.