Abstract A sulfide oxidase enzyme electrode is proposed for monitoring of biogenic sulfide resulting from the activities of sulfate-reducing bacteria (SRB). The enzyme which is immobilized in a carbon (graphite) paste with 1,1’ dimethylferrocene, catalyses the oxidation of sulfide to sulfur. Amperometric measurements were carried out at a fixed potential of 0.3 V, and room temperature, using Tris-HCl buffer (pH 7.5) as the electrolyte, and sodium sulfide solution as the substrate. Under deaerated conditions, the biosensor responded linearly to the tested sulfide concentration in the range of 0–130 ppm. The results indicate that the procedures adopted for the enzyme production and electrode development were reproducible.