Maintenance of previously uncultured freshwater archaea from anoxic waters under laboratory conditions

Abstract

Culture conditions for the maintenance of previously uncultured members of the Archaea thriving in anoxic water layers of stratified freshwater lakes are described. The proposed enrichment conditions, based on the use of defined medium composition and the maintenance of anoxia, have been proven effective for the maintenance of the archaeal community with virtually no changes over time for periods up to 6 months as revealed by a PCR-DGGE analysis. Phylotypes belonging to groups poorly represented in culture collections such as the Deep-Sea Hydrothermal Vent Euryarchaeota (DHVE) and the Miscellaneous Crenarchaeotic Group (MCG) were maintained and selectively enriched when compared to the correspondent indigenous planktonic archaeal community.