Electrocatalysis of Bacterial Membrane Vesicles

The establishment of bioelectrochemical systems is an appealing strategy to further the development of eco-friendly and efficient bioengineering technologies. However, the major biocomponents used as catalysts have been limited to purified enzymes and live microorganisms. Here, we examined the electrocatalytic activity of membrane vesicles (MVs) produced by Shewanella oneidensis MR-1. We demonstrate that the MR-1 MVs exhibit electrocatalysis coupled with formate oxidation over 16 days and a more stable catalytic current compared with live cells. A colorimetric assay and electrochemical analysis revealed that different MV biogenesis routes critically affect the electrocatalytic activity of MVs. Electrochemical analysis of MVs from gene-deletion mutants revealed electron transfer mechanisms between MVs and electrodes in pathways both dependent and independent of c-type cytochromes in MVs. This research highlights MVs as promising platforms for the design of robust and controllable bioelectrocatalysts, paving the way for future research in biosensing, energy conversion, and biochemical production.