title: Negative faradaic resistance in extracellular electron transfer by anode-respiring Geobacter sulfurreducens cells.
abstract: Geobacter sulfurreducens is a gram-negative δ-proteobacterium that is capable of transferring respiratory electrons to solid-state extracellular acceptors, including anodes, via abundant c-type cytochromes expressed in the outer membrane. As extracellular electron transfer (EET) to solid-state acceptors can proceed without the addition of exogenous mediators, this microbe has attracted significant attention with respect to energy conversion between electrical and chemical energy. Here, we revealed that clear redox peaks were present in the whole-cell cyclic voltammogram of G. sulfurreducens at around -0.15 V vs Ag|AgCl when tin-doped In(2)O(3) (ITO) glass was used as an anode. Interestingly, the EET current decreased in the potential region more positive than the midpoint potential (E(m)) of the redox peak. Thus, EET of anode-respiring G. sulfurreducens cells exhibited a negative Faradaic resistance (NFR) characteristic at the E(m) of the redox peak, in contrast to general electrochemical systems where the Faradaic current typically increases with increasing overpotential.
authors: Department of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8156, Japan.
authors: Shoichi
authors: S
authors: Matsuda
authors: Huan
authors: H
authors: Liu
authors: Souichiro
authors: S
authors: Kato
authors: Kazuhito
authors: K
authors: Hashimoto
authors: Shuji
authors: S
authors: Nakanishi
mesh_terms: D004563:Electrochemistry; D004579:Electron Transport; D045302:Geobacter / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis