BACKGROUND: The anode material is considered a key factor influencing the energy conversion in microbial fuel cells (MFCs) because it links microbiology and electrochemistry. To further improve power generation, carbon mesh anodes modified by hydrazine hydrate chemical reduction were applied in air-cathode MFCs. RESULTS: The power densities of MFCs using hydrazine-treated anodes were all higher than the untreated control, among which a 30% hydrazine hydrate-modified anode (CM-30%) showed the best performance. The maximum power density reached 865 mW m(-2), which was 31% higher than the unmodified control (CM-0%, 662 mW m(-2)). The Coulombic efficiency (CE) increased from 10.7% to 13.3% (improved by 24.3%). Furthermore, the acclimation time was reduced from 142 h to 95 h, shortened by 32% compared with the control. Such improvement in MFCs performance was correlated with the increased surface area revealed by scanning electron microscope (SEM) and the change of surface functional groups revealed by X-ray photoelectron spectroscopy (XPS) analysis. This enhancement in MFCs performance was also proved feasible when using real swine wastewater as substrate. CONCLUSIONS: The results indicated that hydrazine hydrate chemical reduction was an effective method for anode modification to improve the performance of MFCs. (C) 2013 Society of Chemical Industry