Electricity production in single-chamber microbial fuel cells using carbon source mixtures and evaluation of anodic biofilms

Microorganisms encounter complex mixtures of carbon sources if lignocellulosic materials, or even wastewaters are used as substrates in order to produce electricity in microbial fuel cells (MFCs). Various carbon sources including monosaccharides, acetate and glucuronic acid were tested in different combinations for electricity production in single chamber air-cathode MFCs. Anodic biofilms enriched at different temperatures using carbon source mixtures were examined using epi-fluorescent, scanning and transmission electron microscopy, and cyclic voltammetry for electrochemical evaluation. Regardless of the mixture composition, all sugars were preferentially/simultaneously utilized to produce electricity during operation. Volatile fatty acid production was observed in all experiments, and varied depending on the sugar combination during MFC operation. Anodic biofilms showed different morphological and electrochemical features depending on the carbon source and MFC conditions. Our results demonstrate that using carbon source mixtures might be advantageous against environmental stress conditions for electricity production in MFCs.