Marine Vibrio spp. protect carbon steel against corrosion through secreting extracellular polymeric substances

The protection of marine materials against corrosion using marine bacterial biofilms is a promising strategy. However, little is known about the mechanisms of this attractive corrosion prevention method. In this work, the corrosion behaviors of X80 carbon steel (CS) in the presence of three different marine Vibrio species were studied. The results demonstrated that all the three Vibrio spp. displayed significant corrosion protection with a weight loss reduction of up to 68%. Moreover, their corrosion prevention performance was tightly related to their abilities to form biofilms, which was in the order of Vibrio sp. EF187016 > Vibrio alginolyticus > Vibrio parahaemolyticus. To further investigate the corrosion prevention mechanism caused by marine biofilms, the extracellular polymeric substances (EPS) of Vibrio sp. EF187016 was extracted and added to 3.5 wt% NaCl for abiotic corrosion testing. The results suggested that the EPS inhibited corrosion, which means EPS can play a significant role in corrosion protection by biofilm.