Increase of riboflavin biosynthesis underlies enhancement of extracellular electron transfer of Shewanella in alkaline microbial fuel cells.
Electrolyte pH tremendously affects the electricity output of microbial fuel cells. However, its underlying molecular mechanism remains elusive, in particular for Shewanella oneidensis MR-1, one of the most widely adopted electrogenic microorganisms. Herein, we found that MFCs were able to deliver a significant (but different) electricity output in a wide range of pH (from 6 to 10), with the maximum at pH=9 (alkaline), which delivers ∼1.5times' higher power output than that at pH=7 (neutral). Furthermore, cyclic voltammetry analysis showed an enhanced electrochemical activity of riboflavin (responsible for extracellular electron transfer of Shewanella) at alkaline pH. Strikingly, the concentration of riboflavin synthesized by Shewanella in MFCs at different pH showed a good correlation with the electricity output of MFCs. Thus, our results substantiated that the increase of riboflavin biosynthesis by Shewanella at the alkaline condition underlies the improvement of the electricity output in MFCs.
Laboratory of eBiorefinery & iMicrobe, Biofuels Institute, School of the Environment, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, Jiangsu Province, China.
Yang-Chun
YC
Yong
Zhao
Z
Cai
Yang-Yang
YY
Yu
Peng
P
Chen
Rongrong
R
Jiang
Bin
B
Cao
Jian-Zhong
JZ
Sun
Jing-Yuan
JY
Wang
Hao
H
Song
D001674:Bioelectric Energy Sources; D004579:Electron Transport; D006863:Hydrogen-Ion Concentration; D012256:Riboflavin / Q000096:biosynthesis*; D020592:Shewanella / Q000378:metabolism*
D012256:Riboflavin