Introducing a novel bacterium, Vibrio neocaledonicus sp., with the highest corrosion inhibition efficiency

• A novel bacterium with the highest corrosion inhibitory effect is introduced.
• From EIS, corrosion resistance of carbon steel increased by more than sixty fold.
• An inhibitory layer covered the entire surface in the first hours of attachment.
• Extracellular polymeric substances of bacterium have a corrosion inhibitory effect.

Degradation of metals due to corrosion causes serious economic problems throughout the world, and different corrosion protection techniques are being used to extend the service life of metallic structures. It has been suggested that some microorganisms can inhibit electrochemical corrosion of metals. Here we isolated a new marine inhibitory bacterium, Vibrio neocaledonicus sp., and EIS results showed that the corrosion resistance of carbon steel increased by more than sixty fold in the presence of this bacterium. This is the highest corrosion inhibitory effect reported for bacteria and is comparable with some industrial coatings such as electroless Ni. This bacterium affected corrosion by the formation of an inhibitory layer on the metal surface in the first hours of attachment, with the consumption of oxygen by electron transport proteins. Extracellular polymeric substances produced by this bacterium also have a corrosion inhibitory effect. Thus we propose a new, natural, non-toxic, and cost-effective system for controlling corrosion processes using this bacterium or extracellular polymeric substances produced by this bacterium.

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