Biocorrosion

Abstract

As is obvious from the other chapters in this book, the sulfate-reducing bacteria (SRB) are currently one of the more intensively studied groups of microorganisms. The reasons for this are not difficult to discern. Their obligate anaerobiosis depends on a number of intriguing variations on standard aerobic respiratory metabolism. This property also determines their considerable significance in the carbon, energy, and sulfur turnover in many anoxic microbial ecosystems. Recent insights from molecular analyses have shown the group to be of particular interest in microbial evolution. However, perhaps the single most important factor stimulating the upsurge of interest in the SRB in recent years has been their considerable, albeit largely negative, ecological and economic impact. In the offshore oil and gas industries, for example, the SRB are implicated in sulfide build-up in enclosed working environments and in seabed pollution under deposits of organically rich drill cuttings (Sanders and Tibbetts, 1987); they are the principal causative organism in microbially influenced corrosion of platform structures, transmission lines, and general equipment (Hamilton, 1985; Cord-Ruwisch et al., 1987); they are the likely cause of major reservoir damage including souring of the produced oil and gas (high sulfide content), and plugging of the geological formation (Herbert, 1987). In applied microbiology, therefore, these various problems are manifestly of major importance to the industries affected by them. The study of the cellular mechanisms involved, however, can also offer rich rewards both to our understanding of microbiological processes themselves, and to our appreciation of how microbial ecosystems interact with and depend on physicochemical components of their immediate environment.