title: Production of electrically-conductive nanoscale filaments by sulfate-reducing bacteria in the microbial fuel cell.
abstract: This study reports that the obligate anaerobic microorganism, Desulfovibrio desulfuricans, a predominant sulfate-reducing bacterium (SRB) in soils and sediments, can produce nanoscale bacterial appendages for extracellular electron transfer. These nanofilaments were electrically-conductive (5.81S·m(-1)) and allowed SRBs to directly colonize the surface of insoluble or solid electron acceptors. Thus, the direct extracellular electron transfer to the insoluble electrode in the microbial fuel cell (MFC) was possible without inorganic electron-shuttling mediators. The production of nanofilaments was stimulated when only insoluble electron acceptors were available for cellular respiration. These results suggest that when availability of a soluble electron acceptor for SRBs (SO4(2-)) is limited, D. desulfuricans initiates the production of conductive nanofilaments as an alternative strategy to transfer electrons to insoluble electron acceptors. The findings of this study contribute to understanding of the role of SRBs in the biotransformation of various substances in soils and sediments and in the MFC.
authors.affiliation: Environmental Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 143-701 Republic of Korea.
authors.forename: Numfon
authors.initials: N
authors.lastname: Eaktasang
authors.affiliation: Environmental Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 143-701 Republic of Korea.
authors.forename: Christina S
authors.initials: CS
authors.lastname: Kang
authors.affiliation: Environmental Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 143-701 Republic of Korea.
authors.forename: Heejun
authors.initials: H
authors.lastname: Lim
authors.affiliation: Environmental Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 143-701 Republic of Korea.
authors.forename: Oh Sung
authors.initials: OS
authors.lastname: Kwean
authors.affiliation: Environmental Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 143-701 Republic of Korea.
authors.forename: Suyeon
authors.initials: S
authors.lastname: Cho
authors.affiliation: Environmental Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 143-701 Republic of Korea.
authors.forename: Yohan
authors.initials: Y
authors.lastname: Kim
authors.affiliation: Environmental Engineering, Konkuk University, 120 Neungdong-ro, Gwangjin-gu, Seoul 143-701 Republic of Korea. Electronic address: hankim@konkuk.ac.kr.
authors.forename: Han S
authors.initials: HS
authors.lastname: Kim
mesh_terms: D001674:Bioelectric Energy Sources / Q000382:microbiology*; D045285:Desulfovibrio desulfuricans / Q000254:growth & development / Q000378:metabolism*; D004553:Electric Conductivity; D004566:Electrodes; D004583:Electrons; D018625:Microscopy, Atomic Force; D053758:Nanoparticles / Q000737:chemistry*; D010084:Oxidation-Reduction; D013431:Sulfates / Q000378:metabolism*
chemical_list: D013431:Sulfates
keywords: Conductive bacterial nanofilament; Desulfovibrio desulfuricans; Insoluble electron acceptor; Microbial fuel cell; Sulfate-reducing bacteria