Adaptation of microbial community of the anode biofilm in microbial fuel cells to temperature.

Temperature as an important ecological factor affects biofilm development and microbial metabolic activity. Here, the performances and microbial communities of microbial fuel cells (MFCs) at different temperature were analyzed. As the temperature decreased, the power output of MFCs declined. A maximum power density of 894.3±48.6mW/m2 was obtained in MFCs operating at 30°C, which was 18.5% and 64.5% higher than that in MFCs at 20°C and 10°C, respectively. Illumina sequencing of 16S rRNA gene amplicons showed that a distinct difference in microbial community structure of the anode biofilms occurred. This resulted in different power outputs of MFCs. Species diversity analyses indicated that species evenness of the anode biofilms shifted beyond species richness at different temperatures. The predominant populations of the anode biofilm shifted from Geobacter and Azonexus (30°C) to Pelobacter (20°C) or Acidovorax, Zoogloea and Simplicispira, (10°C). These results indicate that temperature plays an important role in shaping microbial communities of the anode biofilms in MFCs through changes in species evenness.