Spatial distribution of biofilm conductivity in a Geobacter enriched anodic biofilm

This study assessed the spatial distribution of biofilm conductivity (K-bio) across a multi-centimetre long anodic biofilm grown on an eight-electrode anode array at different growth conditions. A strong correlation was found between the spatial distribution of K-bio and the anodic biofilm thickness (L-f). The K-bio for different electrode pairs ranged between 0.6 and 0.7 mS/cm for L-f of 17-22 mu m and increased to 1.15-1.64 mS/cm upon L-f growth to 38-53 mu m. This increase in K-bio was accompanied by increase in current density from 1.15 +/- 0.12 A/m(2) to 2.1 +/- 0.02 A/m(2). Low half saturation potential was consistently found for electrode pairs having high values of K-bio and L-f. Microbial community revealed the dominance of Geobacter (85%) on all electrode pairs. Acetate concentration significantly influenced the spatial distribution of K-bio. Long-term acetate starvation (3 days) resulted in up to 83% drop in K-bio along with decrease in current density to marginal values (< 0.3 A/m(2)). However, the K-bio and current density rapidly recovered on restoring the acetate feed.

Automated summary

This study evaluated the spatial distribution of biofilm conductivity (K-bio) on an anodic biofilm at different growth conditions. The increase in K-bio was associated with an increase in current density. Geobacter was the dominant microbial community on all electrode pairs. Acetate concentration significantly influenced the spatial distribution of K-bio.