Improving energy accumulation of microbial fuel cells by metabolism regulation using Rhodoferax ferrireducens as biocatalyst.

AIMS

To study the physiology and metabolism of microbial cells in the performance of microbial fuel cells (MFCs).

METHODS AND RESULTS

A dual-chamber MFCs was constructed, and Rhodoferax ferrireducens was used as biocatalyst. To examine the physiology of microbial cells in the performance of MFCs, the anode media containing planktonic cells was replaced with fresh media in which KH(2)PO(4) and/or NH(4)Cl were excluded. The replacing of anode media containing planktonic cells with fresh media excluded of KH(2)PO(4) and NH(4)Cl made the coulombic yield remarkably increased by a factor of 68% (from 29.1 to 46.8C). The results showed that the electricity could be generated with cells in biofilms as biocatalyst, and coulombic yield was improved by limiting cell growth via removal of ingredients in anode media. By supplementation of glucose to the anode media when current declined to baseline, MFCs achieved about same platform current values immediately. MFCs could continue to produce electricity for about 30 h even after glucose was below detection.

CONCLUSIONS

Biofilms and metabolism of glucose play important roles in the performance of MFCs. Coulombic yield of MFCs could be improved by regulating the media ingredients using the stable biofilms-electrode system.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first attempt to study the effect of ingredient compositions of anode media on the performance of MFCs. The observed results that MFCs continued to produce electricity after glucose was below detection was helpful to better understand the mechanism of microbial electricity production.