Objective: Two-chamber microbial fuel cells (MFCs) were set up to understand the electrogenic capacity of MFCs fed with lactic acid to investigate the distribution characteristics of microflora in the anode biofilm, supernatant, and sediment.
Methods: Using lactic acid as a carbon source in the anode, we explored the MFCs start-up process and the efficiency of electricity production, and also investigated the spatial distribution of microbial communities using scanning electron microscope (SEM) and PCR-denaturing gradient gel electrophoresis (DGGE) techniques.
Results: The results indicate that the MFCs reached the highest voltage, 0.56 V on the seventh day after startup. When external resistance and current density was 80 omega and 415 mA/m2, respectively, the power density reached its maximum at 82 mW/m2. SEM revealed that a massive bacillus was attached tightly to the surface of the positive electrode. DGGE profiles revealed that microorganisms on the anode's surface were most similar to that of inoculated sludge, consistent with the major microorganism groups in anode suspension and sludge substrate. Communities developed on the anodes included exoelectrogenic bacteria, i. e. Comamonas testosterone, and Arcobacter butzleri.
Conclusion: This research demonstrates that MFCs fed with lactic acid can generate a high efficiency of current density, and that the dominant microbes on the anodes are similar to that of inoculated sludge.