Updated project metadata. . In this study we show successful use of SWATH-MS for quantitative proteomic analysis of a microbial electrochemically active biofilm. Shewanella oneidensis MR-1 was grown on carbon cloth electrodes under continuous anodic electrochemical polarizations in a bioelectrochemical system. Using lactate as the electron donor, anodes serving as terminal microbial electron acceptors were operated at three different electrode potentials (+0.71V, +0.21V & -0.19V vs. SHE) and the development of catalytic activity was monitored by measuring the current traces over time. Once maximum current was reached (usually within 21-29 hours) the electrochemical systems were shut off and biofilm proteins were extracted from the electrodes for proteomic assessment.