Surface modification of Shewanella oneidensis MR-1 with polypyrrole-dopamine coating for improvement of power generation in microbial fuel cells

Modification of exoelectrogens with conjugated polymers is an efficient strategy to improve extracellular electron transfer (EET) from individual cells to electrode. However, due to the hydrophobic nature of conductive polymers, improving cell-electrode adhesion needs to be addressed. In this research, we report the modification of Shewanella oneidensis MR-1 by successively in situ coating individual cells with polypyrrole (PPy) and adhesive polydopamine (PDA). The PPy-PDA modified cells display improved conductivity and adhesion. We employ PPy-PDA modified cells as anode in microbial fuel cells (MFCs) and find that electro-activity of anode is greatly improved as direct EET is improved, and riboflavin secretion which is conducive to indirect EET is enhanced. The maximum power density of MFCs employing PPy-PDA modified cells is 11.8 and 4.8 higher than that of PPy modified and unmodified cells, respectively. Our results indicate this in situ modification of exoelectrogens with PPY-PDA offers a facile and promising strategy for performance improvement of MFCs.