The sulfate-reducing bacterial community of sulfide-rich water of the Ust'-Kachka resort spring, Perm Krai, Russia

Microbiological investigation of the highly mineralized, sulfide-rich cold spring of the Ust'-Kachka resort was carried out. The total number and biomass of microbial cells were 50 x 10(3) cell/mL and 15 mu g/L, respectively. While the total microbial number was low, the sulfate reduction rate determined by the radioisotope method was relatively high (0.575 mg S L-1 day(-1)). An enrichment culture was obtained on Widdel medium. According to the results of cloning the 16S rRNA gene fragments with subsequent restriction analysis, the dominant organisms were group 6 sulfate-reducing bacteria (Desulfovibrio-Desulfomicrobium) and the microorganism exhibiting 99% similarity to the anaerobic haloalkaliphilic bacterium Halanaerobium hydrogeniformans.