Correlation between circuital current, Cu(II) reduction and cellular electron transfer in EAB isolated from Cu(II)-reduced biocathodes of microbial fuel cells.
The performance of four indigenous electrochemically active bacteria (EAB) (Stenotrophomonas maltophilia JY1, Citrobacter sp. JY3, Pseudomonas aeruginosa JY5 and Stenotrophomonas sp. JY6) was evaluated for Cu(II) reduction on the cathodes of microbial fuel cells (MFCs). These EAB were isolated from well adapted mixed cultures on the MFC cathodes operated for Cu(II) reduction. The relationship between circuital current, Cu(II) reduction rate, and cellular electron transfer processes was investigated from a mechanistic point of view using X-ray photoelectron spectroscopy, scanning electronic microscopy coupled with energy dispersive X-ray spectrometry, linear sweep voltammetry and cyclic voltammetry. JY1 and JY5 exhibited a weak correlation between circuital current and Cu(II) reduction. A much stronger correlation was observed for JY3 followed by JY6, demonstrating the relationship between circuital current and Cu(II) reduction for these species. In the presence of electron transfer inhibitors (2,4-dinitrophenol or rotenone), significant inhibition on JY6 activity and a weak effect on JY1, JY3 and JY5 was observed, confirming a strong correlation between cellular electron transfer processes and either Cu(II) reduction or circuital current. This study provides evidence of the diverse functions played by these EAB, and adds to a deeper understanding of the capabilities exerted by diverse EAB associated with Cu(II) reduction.
Key Laboratory of Industrial Ecology and Environmental Engineering, Ministry of Education (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China.
Jingya
J
Shen
Key Laboratory of Industrial Ecology and Environmental Engineering, Ministry of Education (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China. Electronic address: lipinghuang@dlut.edu.cn.
Liping
L
Huang
College of Chemistry, Dalian University of Technology, Dalian 116024, China.
Peng
P
Zhou
Key Laboratory of Industrial Ecology and Environmental Engineering, Ministry of Education (MOE), School of Environmental Science and Technology, Dalian University of Technology, Dalian 116024, China.
Xie
X
Quan
Environmental Nanocatalysis & Photoreaction Engineering, Department of Chemical Engineering, Loughborough University, Loughborough LE11 3TU, United Kingdom. Electronic address: g.lipuma@lboro.ac.uk.
Gianluca Li
GL
Puma
D019297:2,4-Dinitrophenol / Q000494:pharmacology; D001419:Bacteria / Q000166:cytology* / Q000187:drug effects / Q000302:isolation & purification / Q000378:metabolism*; D001674:Bioelectric Energy Sources / Q000382:microbiology*; D003300:Copper / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D004553:Electric Conductivity; D004566:Electrodes; D004579:Electron Transport / Q000187:drug effects; D012402:Rotenone / Q000494:pharmacology
D012402:Rotenone; D003300:Copper; D019297:2,4-Dinitrophenol
Biocathode; Cu(II) reduction; Electrochemically active bacteria; Electron transfer inhibitor; Microbial fuel cell