Microbiologically influenced corrosion of Cu by marine ammonifying Alcaligenes aquatilis bacterium.

In this work, we studied the microbiologically influenced corrosion mechanism of Cu by marine ammonifying bacterium Alcaligenes aquatilis. Through immersion experiments, we found that A. aquatilis could accelerate the corrosion rate of copper, resulting in the development of pits. In the presence of A. aquatilis, the morphology and composition of the corrosion products differed from the abiotic samples, and we found that Cu2O was the main corrosion product. By analyzing the biotic medium and experimental NH3 addition, we verified that NH3 was the main component that intensified copper corrosion. Furthermore, we found that NH3 played a catalytic role in the corrosion of Cu in the presence of A. aquatilis.

Pseudomonas aeruginosa-accelerated corrosion of Mo-bearing low-alloy steel through molybdenum-mediating chemotaxis and motility.

In this work, we found that the microbiologically influenced corrosion of Pseudomonas aeruginosa was mediated by Mo in low-alloy steel. Through immersion experiments, we found that the corrosion rate of low-alloy steel was not decreased with the addition of 1.0 wt% Mo. However, in the presence of P. aeruginosa, the corrosion rate of the 1.0 wt% Mo steel was accelerated, resulting in the development of pits. Confocal laser scanning microscopy images revealed that more biofilm cells adhered on the 1.0 wt% Mo steel surface. The chemotactic behavior and swimming ability of the bacteria were the main reason for the greater biofilm cell adhesion in the presence of Mo. Using an RNA-seq assay, we verified that both chemotaxis and motility together affected the adhesion of biofilm, and their related genes were affected by Mo.