Effect of proteases secreted from a marine isolated bacterium Bacillus vietnamensis on the corrosion behaviour of different alloys

The adverse corrosion and corrosion inhibitory effects of the marine isolated bacterium Bacillus vietnamensis were determined on different alloys. The corrosion rates of the steel alloys increased in the presence of Bacillu vietnamensis; although the alloys containing Cu were found to be protected from corrosion when exposed to this bacterium. The first assay bacterial mechanism confirmed the presence of protease enzyme, which was then identified by LC-MS/MS analysis. We proposed that Cu ions coordinated with proteases and bonded with water molecules. This coordination process decreased the oxygen availability in the environment, thereby inhibiting the corrosion of the copper alloys. [Display omitted] •A dual role of B. Vietnemensis was observed for steel alloys and Cu alloys.•Protease activity plays a key role on corrosion inhibition of Cu alloys.•The protease enzymes were coordinated to Cu ions and bonded with water molecules.•Pitting was observed on Al-bronze surfaces after inactivation of protease.