title: Electricity generation by Pyrococcus furiosus in microbial fuel cells operated at 90°C.
abstract: Hyperthermophiles are microorganisms that thrive in extremely hot environments with temperatures near and even above 100°C. They are the most deeply rooted microorganisms on phylogenetic trees suggesting they may have evolved to survive in the early hostile earth. The simple respiratory systems of some of these hyperthermophiles make them potential candidates to develop microbial fuel cells (MFC) that can generate power at temperatures approaching the boiling point. We explored extracellular electron transfer in the hyperthermophilic archaeon Pyrococcus furiosus (Pf) by studying its ability to generate electricity in a two-chamber MFC. Pf growing in defined medium functioned as an anolyte in a MFC operated at 90°C, generating a maximum current density of 2 A m-2and a peak power density of 225 mW m-2without the addition of any external redox mediator. Electron microscopy and electrochemical impedance spectroscopy of the anode with the attached Pf biofilm demonstrated bio-electrochemical behavior that led to electricity generation in the MFC via direct electron transfer. This proof of concept study reveals for the first time that a hyperthermophile such as Pf can generate electricity in MFC at extreme temperatures. Biotechnol. Bioeng. 2017;114: 1419-1427. © 2017 Wiley Periodicals, Inc.
authors.affiliation: Nano Electrochemistry Laboratory, College of Engineering, University of Georgia, Athens, Georgia, 30602.
authors.forename: Narendran
authors.identifier: 0000-0001-6600-6032
authors.initials: N
authors.lastname: Sekar
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, 30602.
authors.forename: Chang-Hao
authors.initials: CH
authors.lastname: Wu
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, 30602.
authors.forename: Michael W W
authors.initials: MWW
authors.lastname: Adams
authors.affiliation: Nano Electrochemistry Laboratory, College of Engineering, University of Georgia, Athens, Georgia, 30602.
authors.forename: Ramaraja P
authors.initials: RP
authors.lastname: Ramasamy
mesh_terms: D001422:Bacterial Adhesion / Q000502:physiology; D001674:Bioelectric Energy Sources / Q000382:microbiology*; D018441:Biofilms / Q000254:growth & development*; D004553:Electric Conductivity; D004566:Electrodes; D004579:Electron Transport; D004735:Energy Transfer; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006358:Hot Temperature; D020027:Pyrococcus furiosus / Q000502:physiology*
keywords: Pyrococcus furiosus; electricity; exoelectrogenicity; hyperthermophile; microbial fuel cell