Inhibitory Effect of Vibrio neocaledinocus sp. and Pseudoalteromonas piscicida Dual-Species Biofilms on the Corrosion of Carbon Steel

Multi-species biofilms are found in various bacterial habitats and have industrial relevance. These complex bacterial communities have synergetic effects, unlike a single species. Therefore, it is critical to evaluate these complex communities as a whole. Here, the inhibitory effect of single- and dual-species biofilms of Vibrio neocaledinocus sp. and Pseudoalteromonas piscicida for A36 carbon steel corrosion was investigated. The results demonstrated that the synergistic interactions of the monoculture increased the overall biomass production of the dual-species biofilm, but the growth rate was reduced in the presence of the dual-species culture due to a lack of nutrients. Field emission scanning electron microscopy images also confirmed the development of biofilms—they became more homogenized via exposure time in both the mono- and dual-species cultures. The corrosion resistance of A36 carbon steel positively increased because of the dual-species interactions. This reached the highest value after four weeks of exposure. The highest corrosion inhibition efficiency of 99.8% was achieved in the dual-species cultures. Microbial community analysis revealed the high relative abundance of Pseudoalteromonas piscicida during the initial days of exposure, demonstrating the dominant role of this bacterium in the biofilm structure.