Electron transfer from Shewanella algae BrY to hydrous ferric oxide is mediated by cell-associated melanin
Charles E Turick,
F Caccavo Jr.,
Louis S Tisa,
Corresponding Author
Charles E Turick
Department of Microbiology, University of New Hampshire, Durham, NH 03824-2617, USA
*Corresponding author. Present address: Westinghouse Savannah River Co., Environmental Biotechnology Section, Building 999W, Aiken, SC 29808, USA. Tel.: +1 (803) 819-8407; Fax: +1 (803) 819-8432, E-mail address: [email protected]Search for more papers by this authorF Caccavo Jr.
Department of Microbiology, University of New Hampshire, Durham, NH 03824-2617, USA
Department of Biology, Whitworth College, Spokane, WA 99251, USA.
Search for more papers by this authorLouis S Tisa
Department of Microbiology, University of New Hampshire, Durham, NH 03824-2617, USA
Search for more papers by this authorCharles E Turick,
F Caccavo Jr.,
Louis S Tisa,
Corresponding Author
Charles E Turick
Department of Microbiology, University of New Hampshire, Durham, NH 03824-2617, USA
*Corresponding author. Present address: Westinghouse Savannah River Co., Environmental Biotechnology Section, Building 999W, Aiken, SC 29808, USA. Tel.: +1 (803) 819-8407; Fax: +1 (803) 819-8432, E-mail address: [email protected]Search for more papers by this authorF Caccavo Jr.
Department of Microbiology, University of New Hampshire, Durham, NH 03824-2617, USA
Department of Biology, Whitworth College, Spokane, WA 99251, USA.
Search for more papers by this authorLouis S Tisa
Department of Microbiology, University of New Hampshire, Durham, NH 03824-2617, USA
Search for more papers by this authorAbstract
Shewanella algae BrY uses insoluble mineral oxides as terminal electron acceptors, but the mechanism of electron transfer from cell surface to mineral surface is not well understood. We tested the hypothesis that cell-associated melanin produced by S. algae BrY serves as an electron conduit for bacterial–mineral reduction. Results from Fourier transform infrared spectroscopy and cell surface hydrophobicity assays indicated that extracellular melanin was associated with the cell surface. With H2 as electron donor, washed cell suspensions of melanin-coated S. algae BrY reduced hydrous ferric oxide (HFO) 10 times faster than cells without melanin. The addition of melanin (20 μg ml−1) to these melanin-free cells increased their HFO reduction rate two-fold. These results suggest that cell-associated melanin acts as an electron conduit for iron mineral reduction by S. algae BrY.
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