title: Enhanced photocurrent production by the synergy of hematite nanowire-arrayed photoanode and bioengineered Shewanella oneidensis MR-1.
abstract: Coupling the light-harvesting capabilities of semiconductors with the catalytic power of bacteria is a promising way to increase the efficiency of bioelectrochemical systems. Here, we reported the enhanced photocurrents produced by the synergy of hematite nanowire-arrayed photoanode and the bio-engineered Shewanella oneidensis MR-1 in a solar-assisted microbial photoelectrochemical system (solar MPS) under the visible light. To increase the supply of bioelectrons, the D-lactate transporter, SO1522, was overexpressed in the recombinant S. oneidensis (T-SO1522) that could digest D-lactate 61% faster than the wild-type S. oneidenesis. Without light illumination, the addition of either the wild-type or the recombinant S. oneidensis to the system did not induce any obvious increase in the current output. However, under one-sun illumination, the photocurrent of the abiotic control was 16±2 μA cm-2at 0.8V vs. Ag/AgCl, and the addition of the wild-type S. oneidensis and the recombinant S. oneidensis increased the photocurrent to 70±6 and 95±8 μA cm-2, respectively, at 0.8V vs. Ag/AgCl. Moreover, the solar MPS with T-SO1522 presented quick and repeatable responses to the on/off illumination cycles, and had relatively stable photocurrent generation in the 273-h operation. Scanning electron microscope (SEM) images showed that the cell density on the hematite photoelectrode was similar between the recombinant and the wild-type S. oneidensis. These findings revealed the pronounced influence of metabolic rates on the light-to-electricity conversion in the complex photocatalyst-electricigen hybrid system, which is important to promote the development of the solar MPS for electricity production and wastewater treatment.
authors.affiliation: The Key Laboratory of Water and Sediment Sciences, Ministry of Education, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China; School of Energy Science and Engineering, University of Electronic Science and Technology, Chengdu, Sichuan, 611731, China.
authors.forename: Gaolong
authors.initials: G
authors.lastname: Zhu
authors.affiliation: School of Chemistry and Environment, Beihang University, Beijing 100191, China.
authors.forename: Yun
authors.initials: Y
authors.lastname: Yang
authors.affiliation: The Key Laboratory of Water and Sediment Sciences, Ministry of Education, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China. Electronic address: juan.liu@pku.edu.cn.
authors.forename: Juan
authors.initials: J
authors.lastname: Liu
authors.affiliation: The Key Laboratory of Water and Sediment Sciences, Ministry of Education, College of Environmental Sciences and Engineering, Peking University, Beijing 100871, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Liu
authors.affiliation: The Key Laboratory of Orogenic Belts and Crustal Evolution, School of Earth and Space Sciences, Peking University, Beijing, China.
authors.forename: Anhuai
authors.initials: A
authors.lastname: Lu
authors.affiliation: School of Energy Science and Engineering, University of Electronic Science and Technology, Chengdu, Sichuan, 611731, China. Electronic address: weidong.he@uestc.edu.cn.
authors.forename: Weidong
authors.initials: W
authors.lastname: He
mesh_terms: D001674:Bioelectric Energy Sources; D015374:Biosensing Techniques / Q000379:methods*; D019344:Lactic Acid / Q000737:chemistry; D008027:Light; D008855:Microscopy, Electron, Scanning; D053770:Nanowires / Q000737:chemistry*; D020592:Shewanella / Q000737:chemistry* / Q000378:metabolism; D062065:Wastewater / Q000382:microbiology
chemical_list: D019344:Lactic Acid; D062065:Wastewater
keywords: Bio-engineered Shewanella oneidensis MR-1; Bioelectron supply; Hematite nanowire-arrayed photoelectrode; Light-to-electricity conversion; Solar-assisted microbial photoelectrochemical system