Influence of reduced inorganic sulfur compounds and oxygen on DMS oxidation and DMSO reduction by the marine purple ‘nonsulfur’ bacterium Rhodovulum sul idophilum strain W4

Abstract

The marine purple ‘nonsulfur’ bacterium Rhodovulum sulfidophilum strain W4 uses dimethyl sulfide (DMS) as electron donor and dimethyl sulfoxide (DMSO) as electron acceptor. Characteristics of both reactions were investigated. Cells oxidize DMS to DMSO phototrophically under anoxic and oxic conditions, and chemotrophically under oxic conditions. Sulfide inhibits strongly and compatitively the oxidation of DMS. In the dark, Rhodovulum sulfidophilum strain W4 reduces DMSO to DMS with acetate as electron donor under anoxic and oxic conditions in similar rates. Sulfide and thiosulfate stimulate significantly the chemotrophic reduction of DMSO to DMS. Key words