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It was found that seven strains of bacteria can cause corrosion damage to aluminum, its alloys, and zinc. With respect to the studied metals, the most active bacteria were Proteus vulgaris 1212 and Pseudomonas aeruginosa 969. Superoxide anion radicals were demonstrated to play a role in the initiation of corrosive damage to aluminum and zinc, while bacterial exometabolites participate in the later stages of this process.

A by-product of oxygen biotransformation during the life of bacteria is the superoxide ion , which quite easily, including nonenzymatically, can turn into the stable product H2O2, which, as is well known, may exhibit corrosive properties for metals. Thus, the vital products of bacterial can act on a metal not only as chemical agents, they can also electrochemically stimulate corrosion. To identify the nature of the elementary stages of biocorrosion, an attempt was made to simulate electrochemical corrosion of zinc using well-known electrochemical methods. Zinc corrosion occurs by two electrochemical mechanisms: corrosion by oxygen depolarization and oxidation of zinc by hydrogen peroxide. The limiting stage of the corrosion process is diffusion of the oxidizing agents to the zinc surface. [ABSTRACT FROM AUTHOR]

Abstract: We have hypothesized that products of oxygen biotransformation by a microbial electron transport chain, for example, superoxide anion and the product of its disproportionation, hydrogen peroxide, play a key role in aerobic biocorrosion. The goal of the present work was to evaluate the role of superoxide anion and its derivatives in initiation of bacterial corrosion and its dependence on the composition of nutrient medium. [ABSTRACT FROM AUTHOR]