Halo(natrono)archaea from hypersaline lakes can utilize sulfoxides other than DMSO as electron acceptors for anaerobic respiration

Dimethylsulfoxide (DMSO) has long been known to support anaerobic respiration in a few species of basically aerobic extremely halophilic euryarchaea living hypersaline lakes. Recently, it also shown be utilized as an additional electron acceptor sulfur-reducing haloarchaea. Here we investigated whether haloarchaea would capable with other two sulfoxides, methionine sulfoxide (MSO) and tetramethylene (TMSO). For this, enrichment cultures were inoculated sediments from salt soda lakes southwestern Siberia southern Russia. Positive enrichments obtained for both MSO TMSO yeast extract but not formate or acetate the donor. Two pure lakes, either TMSO, obligate anaerobes closely related Halanaeroarchaeum sulfurireducens, although type strain this genus was unable utilize any sulfoxides. isolated facultatively alkaliphilic using O2, sulfur sulfoxides acceptors. One isolate identical previously described Natrarchaeobaculum while another one, enriched at lower alkalinity, is forming new Halobiforma. Since all isolates able respire three including DMSO corresponding activities cross-induced, suggest that single enzyme DMSO-reductase family broad substrate specificity responsible various sulfoxide-dependent