Engineered Living Biofilm with Enhanced Metal Binding Ability for Corrosion Protection in Seawater

Engineering living functional biofilms offers an ecofriendly and efficient technique for the corrosion protection of metallic materials in marine environments. Its firm attachment to the metal surface is a key step to effectively improve the corrosion protection. Herein, engineered Escherichia coli biofilm with strong metal binding ability is constructed by genetically appending a metal binding domain (MBD) to extracellular amyloids. The engineered living biofilm improved the corrosion resistance of X70 carbon steel. Moreover, a biofilm-induced mineralization layer, mainly composed of calcite, is formed on the X70 surface, which provided a stable corrosion barrier. At the end of 7-days immersion, the icorr decreased from 5.1 ± 0.4 µA cm−2 without biofilm to 0.5 ± 0.1 µA cm−2 with E. coli MBD biofilm, resulting in a corrosion inhibition efficiency of 90.2%. It also demonstrated the corrosion protection effect for 304 stainless steel, suggesting possible broad applications of the engineered biofilm. The application of synthetic biology offers a novel approach in the development of anti-corrosion technologies in water environments.