Synergistic effect on corrosion behavior of X80 steel influenced by Pseudomonas aeruginosa and Acetobacter aceti

Pseudomonas aeruginosa and Acetobacter aceti, as electroactive bacteria and acid-producing bacteria respectively, have the potential to cause severe corrosion of metallic materials. Microbiologically influenced corrosion by a single bacterial species has been widely observed and studied. However, the corrosion behavior and mechanisms associated with the simultaneous presence of these two different types of bacteria on metallic materials have been rarely reported. This study, focusing on the mixed-bacteria system, P. aeruginosa and A. aceti, examined the corrosion behavior of X80 steel under these combined bacterial conditions. A comparative analysis was conducted using a single bacterial species as a control. The corrosion-promoting mechanism of the two types of bacteria was investigated by analyzing the role of bacterial metabolites in the corrosion process. Under mixed bacterial conditions, the pitting depth on the surface of X80 steel measured 8.3 μm, significantly surpassing that under single-strain conditions (5.6 μm and 7.3 μm, respectively). Electrochemical test results confirmed these findings. PCN produced by P. aeruginosa facilitated electron transfer during the corrosion process of A. aceti, promoting the latter’s growth as well. Simultaneously, acetate produced during corrosion promoted the growth of P. aeruginosa. The symbiotic and mutually reinforcing interactions between the two bacteria result in accelerated corrosion of X80 steel.