Metabolic characteristics of Archaeoglobi

Abstract:

Archaeoglobi is a class of thermophilic Archaea belonging to the Euryarchaeota, covering three genera:Archaeoglobus, Geoglobus and Ferroglobus. Archaeoglobus are all heterotrophic or chemolithotrophic sulfate reducers using sulfate, sulfite or thiosulfate as electron acceptors, with the formation of hydrogen sulfide as the end product. Geoglobus and Ferroglobus may reduce both nitrate and ferric irons. Archaeoglobi are strictly thermophilic anaerobes, which are widely distributed the natural environments and are dominant in some environments, such as oceans, terrestrial hydrothermal systems and terrain environments. Due to wide geographic distribution and diverse metabolic potential, and activity perform in metabolism of various elements, Archaeoglobi may play an important role in the global element cycle and has become a scenic spot for microbial ecology research. Members of Archaeoglobi phylogenetically close to methanogenic Euryarchaeota in their evolutionary history; on the other hand, fuctional genes of archaeal type Wood-Ljungdahl (WL) pathway are present in partial Archaeoglobi genomes, even the newest studies suggest that uncultured Archaeoglobi genomes contain complete mathanogensis pathway, these evidences provides new insights into the evolutionary transition from methanogenic archaea to sulfate-reducing bacterial. This review collected the information of the physiological, biochemical characteristics and genome analysis of eleven reported Archaeoglobi strains, summarized the metabolic characteristics of those isolated Archaeoglobi in terms of the aspects of chemolithoautotrophic, chemotherapeutic, sulfite reduction, acetogenesis, methanogenesis, and analyzed the potential metabolic functions of uncultured Archaeoglobi genomes based on the metagenomic information, which may provide theoretical guidance for the further isolation and cultivation of this kind of uncultured anaerobic microorganisms.