title: The catalytic effect of TiO2nanosheets on extracellular electron transfer of Shewanella loihica PV-4.
abstract: Electron transfer kinetics of Shewanella loihica PV-4 at the up-growing TiO2nanosheet (TiO2-NS) modified carbon paper (CP) electrode was investigated. The effect of TiO2-NSs, which speeds up the interfacial electron transfer of outer membrane c-type cytochromes (OMCs), was revealed for the first time. TiO2-NSs with a polar surface modified hydrophobic CP into super-hydrophilic TiO2-NS/CP. The favorable interaction between PV-4 and TiO2-NSs not only enhanced microbial adhesion, but also altered the redox nature of OMCs. The mid-point potential of OMCs at TiO2-NS/CP was shifted to a more negative potential, indicating a higher thermodynamic driving force for the protein to release electrons. Moreover, electron transfer from OMCs to TiO2-NSs was also benefited from the positive shift of flat-band potential Vfbowing to reduced pH at the electrode/microorganism interface, as well as good electrical conductivity of TiO2-NSs. As a result, the electron transfer rate constant ketof OMCs at the TiO2-NS/CP anode was about three times faster than that at the CP anode. The accelerated electron transfer kinetics as well as 15% increase of biomass together accounted for a 97% increase of the maximum output power density in the MFC. The result expanded our knowledge about the role of a designed TiO2nanostructure in microbial electron transfer that can be applied in other bio-electrochemical systems.
authors.affiliation: State Key Laboratory of Bioelectronics, Southeast University, Nanjing, 210096, People's Republic of China. fudegang@seu.edu.cn.
authors.forename: Tao
authors.initials: T
authors.lastname: Yin
authors.affiliation: State Key Laboratory of Bioelectronics, Southeast University, Nanjing, 210096, People's Republic of China. fudegang@seu.edu.cn.
authors.forename: Hui
authors.initials: H
authors.lastname: Li
authors.affiliation: State Key Laboratory of Bioelectronics, Southeast University, Nanjing, 210096, People's Republic of China. fudegang@seu.edu.cn.
authors.forename: Lin
authors.initials: L
authors.lastname: Su
authors.affiliation: State Key Laboratory of Bioelectronics, Southeast University, Nanjing, 210096, People's Republic of China. fudegang@seu.edu.cn.
authors.forename: Shuo
authors.initials: S
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Bioelectronics, Southeast University, Nanjing, 210096, People's Republic of China. fudegang@seu.edu.cn.
authors.forename: Chunwei
authors.initials: C
authors.lastname: Yuan
authors.affiliation: State Key Laboratory of Bioelectronics, Southeast University, Nanjing, 210096, People's Republic of China. fudegang@seu.edu.cn and Suzhou Key Laboratory of Environment and Biosafety, Suzhou, 215123, People's Republic of China and Jiangsu Key Laboratory for Biomaterials and Devices, Southeast University, Nanjing, 210096, People's Republic of China.
authors.forename: Degang
authors.initials: D
authors.lastname: Fu
mesh_terms: D002384:Catalysis; D003574:Cytochrome c Group / Q000378:metabolism; D004579:Electron Transport; D004583:Electrons; D049329:Nanostructures; D010084:Oxidation-Reduction; D020592:Shewanella / Q000378:metabolism*; D014025:Titanium
chemical_list: D003574:Cytochrome c Group; C009495:titanium dioxide; D014025:Titanium