Microbiologically influenced corrosion inhibition induced by S. putriefaciens mineralization under extracellular polymeric substance regulation via FlrA and FlhG genes

The effect of microbially-induced mineralization on the corrosion inhibition of carbon steel was investigated using ΔflrA and ΔflhG mutant strains of Shewanella putrefaciens. Deletion of FlrA and FlhG genes could induce the up/down-regulation of extracellular polymeric substance (EPS) expression, respectively, without interfering the bacterial growth. Compared to the wild-type strain, the ΔflrA mutant exhibited a ∼ 26 % increase in corrosion inhibition rate due to its significantly higher mineralization rate and formation of a high-quality mineralized layer. The ΔflhG mutant retained mineralization ability, but the discontinuous mineralized products failed to inhibit corrosion, and the corrosion rate increased by ∼ 1.7 times.