Enhancement of exogenous riboflavin on microbiologically influenced corrosion of nickel by electroactive Desulfovibrio vulgaris biofilm

Abstract This work gives the latest insights into the pure nickel (Ni) microbiologically influenced corrosion (MIC) induced by Desulfovibrio vulgaris (D. vulgaris). Riboflavin, a soluble redox mediator for electron transfer, is involved in a variety of redox processes in biogeochemical systems. By comparison, 20 ppm riboflavin dramatically enhanced the Ni MIC (59% increase in weight loss), while the Cu MIC showed no effect due to the fact that Cu MIC was metabolite (M)-MIC. Furthermore, H2 detection in the headspace revealed that neither proton nor H2S corrosion occurred in the Ni MIC (Cu MIC caused by the biogenic H2S produced copious amounts of H2, whereas the Ni MIC did not). The experimental results and thermodynamic analysis indicated that Ni D. vulgaris MIC was energetically generated by trapping electrons, which was classified as extracellular electron transfer (EET)-MIC.