The effect of Pseudoxanthomonas sp. as manganese oxidizing bacterium on the corrosion behavior of carbon steel

The present study investigated the role of manganese oxidizing bacterium (MOB), namely Pseudoxanthomonas sp. on the corrosion behavior of carbon steel. This bacterium was isolated from sewage treatment plants and identified by biochemical and molecular methods. The electrochemical techniques such as open circuit potentiometry, electrochemical impedance spectroscopy, potentiodynamic and cyclic polarization were used to measure the corrosion rate and observe the corrosion mechanism. Also, scanning electron microscopy and X-ray diffraction studies were applied to surface analysis. This study revealed the strong adhesion of the biofilm on the metal surface in the presence of Pseudoxanthomonas sp. that enhanced the corrosion of carbon steel. X-ray diffraction patterns identified a high content of MnO2 deposition within these biofilms. This is the first report that discloses the involvement of Pseudoxanthomonas sp. as manganese oxidizing bacteria on the corrosion of carbon steel.

► A new type of manganese oxidizing bacteria, namely Pseudoxanthomonas sp. was indicated.
► This bacterium can create a biofilm on the part of metal surface and affect localized corrosion.
► In the presence of biofilm, the diffusion of oxygen vacancies and manganese ions has occurred.