Microbial stratification structure within cathodic biofilm of the microbial fuel cell using the freezing microtome method

The aim of this study was to investigate the microbial stratification structure within cathodic biofilm of the microbial fuel cell (MFC) using the freezing microtome method. Experiments were conducted in a single-chamber air-cathode MFC with 0.8 g/L maltodextrin as substrate for similar to 30 d operation. The maximum power density was 945 +/- 10 mW/m(2) in the MFC. Maltodextrin resulted in the relative abundance of Candidatus Saccharibacteria of 37.0% in the anodic biofilm. Different bacterial communities were identified in different layers within the cathodic biofilm. The relative abundance of Enterococcus was 3.7%, 10.5%, and 1.6% in the top (100-150 mu m), middle (50-100 mu m), and bottom (0-50 mu m) layers, respectively. Higher bacterial viability was observed within the top and bottom layers of the cathodic biofilm. Understanding the stratification of bacterial community in cathodic biofilm should be important to control the cathodic biofilm in the MFC. (C) 2017 Elsevier Ltd. All rights reserved.