Dimethyl sulphoxide reduction with reduced sulphur compounds as electron donors by anoxygenic phototrophic bacteria

The marine purple non-sulphur bacterium Rhodovulum euryhalinum strain DSM 4868 reduced dimethyl sulphoxide (DMSO) to dimethyl sulphide (DMS) chemotrophically with sulphide as electron donor. The oxidation of sulphide was correlated with the formation of polysulphides. R. euryhalinum reduced DMSO phototrophically with sulphide as well, but the amount of DMSO reduced in relation to sulphide oxidized was lower. The marine green sulphur bacterium Chlorobium vibrioforme strain DSM 8327 reduced DMSO to DMS phototrophically with sulphide and thiosulphate as electron donors. The extent of DMSO reduction was much less in the dark. Eight strains of purple sulphur bacteria - marine, brackish water and freshwater isolates - and another marine green sulphur bacterium showed a very weak capacity for DMSO reduction with sulphide or thiosulphate as electron donors in the light and dark, respectively.