Thiomicrospira halophila sp. nov., a moderately halophilic, obligately chemolithoautotrophic, sulfur-oxidizing bacterium from hypersaline lakes

Abstract

Enrichments at 2 M NaCl and pH 7?5-8, with thiosulfate or sulfide as electron donor, inoculated with sediments from hypersaline chloride-sulfate lakes of the Kulunda Steppe (Altai, Russia) resulted in the domination of two different groups of moderately halophilic, chemolithoautotrophic, sulfur-oxidizing bacteria. Under fully aerobic conditions with thiosulfate, bacteria belonging to the genus Halothiobacillus dominated while, under microaerophilic conditions, a highly motile, short vibrio-shaped phenotype outcompeted the halothiobacilli. Three genetically and phenotypically highly similar vibrio-shaped isolates were obtained in pure culture and one of them, strain HL 5 T , was identified as a member of the Thiomicrospira crunogena cluster by 16S rRNA gene sequencing. The new isolates were able to grow with thiosulfate as electron donor within a broad salinity range from 0?5 to 3?5 M NaCl with an optimum at 1?5 M and within a pH range from 6?5 to 8?5 with an optimum at pH 7?5-7?8. Comparative analysis of ribulose-1,5-bisphosphate carboxylase/ oxygenase (RuBisCO) gene sequences demonstrated that strain HL 5 T possessed two genes, cbbL-1 and cbbL-2, of the form I RuBisCO and a cbbM gene of the form II RuBisCO, similar to the other members of the Thiomicrospira crunogena cluster. On the basis of phenotypic and genetic comparison, the new halophilic isolates are proposed to be placed into a novel species, Thiomicrospira halophila sp. nov. (type strain HL 5 T =DSM 15072 T =UNIQEM U 221 T ).

Influence of Microbially Reducible Fe(III) on the Bacterial Community Structure of Estuarine Surface Sediments

“…Although the native sediments were populated largely with microorganisms involved in sulfate reduction and sulfide oxidation at the time of sediment collection, the addition of ferrihydrite shifted the microbial community towards clones affiliated with microorganisms involved in the reduction of elemental sulfur (e.g., Desulfuromonas) (Pfennig and Biebl 1976;Finster et al 1997) and its oxidation (e.g., Thioalkalispira, Sulfurovum, and Thiomicrospira) (Brinkoff et al 1999;Inagaki et al 2004;Sorokin et al 2002Sorokin et al , 2006 (Table 3), possibly attributable to abiotic oxidation of sulfide by ferrihydrite. Some species of Desulfuromonas have also been shown to directly reduce Fe(III) (Coates et al 1995;Vandieken et al 2006).…”

Novel sulfur‐oxidizing streamers thriving in perennial cold saline springs of the Canadian high Arctic

“…The reason for the lack of streamers at CP is not clear. The CP springs also have snow covered run‐off streams; however, the increased concentration of salts at CP (∼15.5%) as compared with GH (∼7.5%) may inhibit the formation of Thiomicrospira streamers as the tolerance of validly characterized species of Thiomicrospira (including the psychrophilic species, T. arctica and psychrophila ) are typically between ∼0–1.24 M NaCl (0–7.2% NaCl) (Sorokin et al ., 2006). The recently described T. halophila can tolerate NaCl levels of up to 3.5 M NaCl (∼20.5% NaCl); however, this isolate has an optimum growth temperature of 30°C and is not capable of growth at 0°C (Sorokin et al ., 2006).…”

Diversity of culturable halophilic sulfur-oxidizing bacteria in hypersaline habitats

“…3). They have recently been described as a new species, Thiomicrospira halophila (Sorokin et al, 2006b). With deepsea brines from Urania Basin, only the rod-shaped phenotype was present in the enrichments at 2 M NaCl.…”