Shewanella oneidensis as a living electrode for controlled radical polymerization

Metabolic engineering has facilitated the production of pharmaceuticals, fuels, and soft materials but is generally limited to optimizing well-defined metabolic pathways. We hypothesized that the reaction space available to metabolic engineering could be expanded by coupling extracellular electron transfer to the performance of an exogenous redox-active metal catalyst. Here we demonstrate that the electroactive bacterium Shewanella oneidensis can control the activity of a copper catalyst in atom-transfer radical polymerization (ATRP) via extracellular electron transfer. Using S. oneidensis, we achieved precise control over the molecular weight and polydispersity of a bioorthogonal polymer while similar organisms, such as Escherichia coli, showed no significant activity. We found that catalyst performance was a strong function of bacterial metabolism and specific electron transport proteins, both of which offer potential biological targets for future applications. Overall, our results suggest that manipulating extracellular electron transport pathways may be a general strategy for incorporating organometallic catalysis into the repertoire of metabolically controlled transformations.