Desulfosporosinus lacus sp. nov., a sulfate-reducing bacterium isolated from pristine freshwater lake sediments.

A novel sulfate-reducing bacterium was isolated from pristine sediments of Lake Stechlin, Germany. This strain, STP12(T), was found to contain predominantly c-type cytochromes and to reduce sulfate, sulfite and thiosulfate using lactate as an electron donor. Although STP12(T) could not utilize elemental sulfur as an electron acceptor, it could support growth by dissimilatory Fe(III) reduction. In a comparison of 16S rRNA gene sequences, STP12(T) was 96.7 % similar to Desulfosporosinus auripigmenti DSM 13351(T), 96.5 % similar to Desulfosporosinus meridiei DSM 13257(T) and 96.4 % similar to Desulfosporosinus orientis DSM 765(T). DNA-DNA hybridization experiments revealed that strain STP12(T) shows only 32 % reassociation with the type strain of the type species of the genus, D. orientis DSM 765(T). These data, considered in conjunction with strain-specific differences in heavy metal tolerance, cell-wall chemotaxonomy and riboprint patterns, support recognition of strain STP12(T) (=DSM 15449(T)=JCM 12239(T)) as the type strain of a distinct and novel species within the genus Desulfosporosinus, Desulfosporosinus lacus sp. nov.