Bioelectricity and bioactive compound productionin an algal-assisted microbial fuel cell with immobilized bioanode

This study investigates the influence of immobilized bacterial anode on the performance of algal-assisted microbial fuel cell (AAMFC) that treats dairy wastewater with concurrent bioelectricity and bioactive compound production. Immobilized exoelectrogenic bacterium-Enterobacter aerogenes-was used in the anode region, andNostocsp. was used in the cathode region. The investigation on the influence of sodium alginate (SA) concentration indicated thatE. aerogenesimmobilized using 20 g/L SA produced highest power density of 168 +/- 3.5 mW/m(2), whereas free cells showed 75 +/- 5.32 mW/m(2). The coulombic efficiency, chemical oxygen demand (COD) removal, and volatile fatty acid (VFA) recovery obtained for cells immobilized using 20 g/L SA were 12.54, 83.15, and 92%, respectively. This system gave a CO(2)supply of 4.2 mM, which increased the productivity ofNostocsp. to 64.3 +/- 3.8 mg/L d. Algal cathode produced a maximum dissolved oxygen content of 12.8 mg/L. The constituents ofNostocsp. were extracted using ethanol, and the antimicrobial activity of the extract was tested against aquatic bacterial pathogens. The extract at a dosage of 500 mu g showed highest zone of inhibition of 11 mm for the gram-negative bacteriaCitrobacter freundiiand least inhibition of 2 mm forEscherichia coli. FTIR analysis of the extract confirmed the presence of bioactive compounds. This study substantiated that the immobilized anodic exoelectrogens with microalgal biocathode in an AAMFC will find a promising application in energy harvesting from wastewater and bioactive compound synthesis.

Automated summary

This study investigates the influence of immobilized bacterial anode on the performance of algal-assisted microbial fuel cell (AAMFC) that treats dairy wastewater. The results show that using immobilized bacteria can improve power density, COD removal, and VFA recovery in the fuel cell.