Adaptive bidirectional extracellular electron transfer during accelerated microbiologically influenced corrosion of stainless steel

Ziyu Li,Dawei Zhang,Weiwei Chang,Tianyu Cui,Hongchang Qian,Hao Song,Tingyue Gu,Arjan Mol,Yuntian Lou,Fahe Cao,Xiaogang Li,Dake Xu

doi:10.1038/s43246-021-00173-8

Abstract

Microbiologically influenced corrosion of metals is prevalent in both natural and industrial environments, causing enormous structural damage and economic loss. Exactly how microbes influence corrosion remains controversial. Here, we show that the pitting corrosion of stainless steel is accelerated in the presence of Shewanella oneidensis MR-1 biofilm by extracellular electron transfer between the bacterial cells and the steel electrode, mediated by a riboflavin electron shuttle. From pitting measurements, X-ray photoelectron spectroscopy and Mott-Schottky analyses, the addition of an increased amount of riboflavin is found to induce a more defective passive film on the stainless steel. Electrochemical impedance spectroscopy reveals that enhanced bioanodic and biocathodic process can both promote the corrosion of the stainless steel. Using in situ scanning electrochemical microscopy, we observe that extracellular electron transfer between the bacterium and the stainless steel is bidirectional in nature and switchable depending on the passive or active state of the steel surface.

Highlights

Influenced corrosion of metals is prevalent in both natural and industrial environments, causing enormous structural damage and economic loss
The aggravated pitting by the bacteria with added riboflavin was supported by the ionic leaching results from inductively coupled plasma mass spectrometry (ICP–MS) (Fig. 1b), which showed that in the presence of the bacteria, the medium containing a higher concentration of riboflavin caused a significantly higher metal loss
We have demonstrated that bacteria could corrode steels via bioanodic or biocathodic electron transfer (EET) in adaptation to the passive or active state of the steel surface

Summary

Introduction

Influenced corrosion of metals is prevalent in both natural and industrial environments, causing enormous structural damage and economic loss. We show that the pitting corrosion of stainless steel is accelerated in the presence of Shewanella oneidensis MR-1 biofilm by extracellular electron transfer between the bacterial cells and the steel electrode, mediated by a riboflavin electron shuttle. Extracellular electron transfer (EET) between bacteria and a metal surface (acting as an electrode) has been studied as a fundamental mechanism of metal corrosion caused by bacteria especially within the last ten years[1,8,9,10,11]. Recent studies on microbial fuel cells (MFCs) have identified bidirectional EET in S. oneidensis MR-1, which was able to oxidize or reduce extracellular electrodes if different redox potentials were applied to inert carbon-based electrodes[19].

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