Evaluation of microbial corrosion in biofuel storage tanks using split-chamber zero resistance ammetry

Split-chamber zero resistance ammetry (SC-ZRA) was used to study microbiologically influenced corrosion by aerobic chemoorganotrophic microeukaryotes isolated from biodiesel storage tanks. The magnitude and direction of electric current were measured between two shorted carbon steel electrodes, which were deployed in separate chambers connected by a salt bridge (via a SC-ZRA assembly). This approach permitted rapid screening for the corrosive activity of these previously understudied microeukaryotes. During this study, two previously understudied microeukaryotes (Byssochlamys sp. SW2 and Yarrowia lipolytica) showed increased biomass, an increase in electrochemical signal (current), and a corresponding increase in corrosion rate (weight loss). However, other previously understudied microeukaryote (Wickerhammomyces sp. SE3) showed an increase in biomass without an increase in electrochemical signal and minimal corrosion rate, indicating that the SC-ZRA technique can screen for the corrosive activity of a microorganism, regardless of overall microbial activity. This technique could be used to quickly assess the corrosive potential for a range of previously understudied microorganisms. Graphical Abstract: [Figure not available: see fulltext.].