Desulfovibrio vulgaris as a model microbe for the study of corrosion under sulfate-reducing conditions

Corrosion of iron-containing metals under sulfate-reducing conditions is an economically important problem. Microbial strains now known as Desulfovibrio vulgaris served as the model microbes in many of the foundational studies that developed existing models for the corrosion of iron-containing metals under sulfate-reducing conditions. Proposed mechanisms for corrosion by D. vulgaris include: (1) H₂ consumption to accelerate the oxidation of Fe⁰ coupled to the reduction of protons to H₂; (2) production of sulfide that combines with ferrous iron to form iron sulfide coatings that promote H₂ production; (3) moribund cells release hydrogenases that catalyze Fe⁰ oxidation with the production of H₂; (4) direct electron transfer from Fe⁰ to cells; and (5) flavins serving as an electron shuttle for electron transfer between Fe⁰ and cells. The demonstrated possibility of conducting transcriptomic and proteomic analysis of cells growing on metal surfaces suggests that similar studies on D. vulgaris corrosion biofilms can aid in identifying proteins that play an important role in corrosion. Tools for making targeted gene deletions in D. vulgaris are available for functional genetic studies. These approaches, coupled with instrumentation for the detection of low concentrations of H₂, and proven techniques for evaluating putative electron shuttle function, are expected to make it possible to determine which of the proposed mechanisms for D. vulgaris corrosion are most important.