Enhanced Shewanella oneidensis MR-1 anode performance by adding fumarate in microbial fuel cell

•Fumarate addition enhanced the electricity generation of Shewanella cells.•Fumarate could promote the bacteria propagation and the anode biofilm formation.•The riboflavin secretion of Shewanella cells was impaired with fumarate addition.

The anode biofilm plays an important role in the microbial fuel cell (MFC) performance, which relies on the catalytic function of the anodic biofilm to transform the chemical energy into electricity energy. In this study, fumarate, as a kind of electron acceptor, is added into the anode system of MFC to figure out its effect on the biofilm formation of S. oneidensis MR-1. With fumarate addition, more bacteria are observed on the anode surface, and the power density has been promoted by 2.41 times than that without fumarate. Mechanism analysis shows that the fumarate addition could impair the secretion of riboflavin and inhibit the indirect electron transfer process, by finishing the respiration process with fumarate as electron acceptor, which promoted the bacteria proliferation and the anode biofilm formation.