Ecophysiology of “ Halarsenatibacter silvermanii ” Strain SLAS-1 T , gen. nov., sp. nov., a Facultative Chemoautotrophic Arsenate Respirer from Salt-Saturated Searles Lake, California

Abstract

Searles Lake occupies a closed basin harboring salt-saturated, alkaline brines that have exceptionally high concentrations of arsenic oxyanions. Strain SLAS-1 ^T was previously isolated from Searles Lake (R. S. Oremland, T. R. Kulp, J. Switzer Blum, S. E. Hoeft, S. Baesman, L. G. Miller, and J. F. Stolz, Science 308:1305-1308, 2005). We now describe this extremophile with regard to its substrate affinities, its unusual mode of motility, sequenced arrABD gene cluster, cell envelope lipids, and its phylogenetic alignment within the order Halanaerobacteriales , assigning it the name “ Halarsenatibacter silvermanii ” strain SLAS-1 ^T . We also report on the substrate dynamics of an anaerobic enrichment culture obtained from Searles Lake that grows under conditions of salt saturation and whose members include a novel sulfate reducer of the order Desulfovibriales , the archaeon Halorhabdus utahensis , as well as a close homolog of strain SLAS-1 ^T .