Pyocyanin-modifying genes phzM and phzS regulated the extracellular electron transfer in microbiologically-influenced corrosion of X80 carbon steel by Pseudomonas aeruginosa

Abstract In Pseudomonas aeruginosa, phzM and phzS genes encode two enzymes that convert phenazine‑1‑carboxylate to pyocyanin (PYO), which is an efficient mediator for EET. Herein, an aerobic P. aeruginosa mutant strain with phzM and phzS genes knockout was used to confirm that phzM and phzS genes regulate EET-MIC of X80 carbon steel. The inhibition efficiency of MIC by mutant strain reached ∼48%, demonstrating that MIC was considerably suppressed since the mutant strain was no longer capable of producing sufficient PYO. When organic carbon was deficient, P. aeruginosa could utilise iron as an electron donor and caused more severe corrosion via EET.