Dynamic changes in the microbial community composition in microbial fuel cells fed with sucrose

Area of Science:

• Microbial Ecology
• Bioelectrochemistry
• Environmental Microbiology

Background:

• Microbial fuel cells (MFCs) harness microbial activity for electricity generation.
• Understanding the bacterial communities in MFC anodes is crucial for optimizing performance.
• Anodic biofilm dynamics influence the efficiency of power output.

Purpose of the Study:

• To investigate the performance and dynamics of bacterial communities in MFC anodes.
• To correlate bacterial community structure with electricity production.
• To identify key bacterial species or groups involved in power generation.

Main Methods:

• Denaturing gradient gel electrophoresis (DGGE) of 16S rRNA genes to analyze bacterial community structure.
• PCR amplification and sequencing for species identification.
• Correlation analysis between species proportions and MFC power density.
• Pareto-Lorenz evenness distribution to assess community structure and shifts.

Main Results:

• Replicate MFCs showed similar performance but divergent bacterial community evolution.
• No direct correlation was found between specific species proportions and power output enhancement.
• Putative exoelectrogenic denitrifiers and sulphate-reducers comprised ~24% of the final biofilm community.
• Community analysis revealed shifts between functionally similar species, indicating functional redundancy.

Conclusions:

• Anodic bacterial communities in MFCs exhibit functional redundancy, allowing adaptation to changing conditions.
• Stable MFC performance can be maintained despite shifts in specific bacterial populations.
• The ability for electricity generation may be widespread among diverse bacterial taxa.