Manganite reduction by Shewanella putrefaciens MR-4

Abstract

Other| December 01, 1998 Manganite reduction by Shewanella putrefaciens MR-4 Inga Larsen; Inga Larsen Center for Great Lakes Studies, Milwaukee, WI, United States Search for other works by this author on: GSW Google Scholar Brenda Little; Brenda Little Search for other works by this author on: GSW Google Scholar Kenneth H. Nealson; Kenneth H. Nealson Search for other works by this author on: GSW Google Scholar Richard Ray; Richard Ray Search for other works by this author on: GSW Google Scholar Alain Stone; Alain Stone Search for other works by this author on: GSW Google Scholar Juihan Tian Juihan Tian Search for other works by this author on: GSW Google Scholar Author and Article Information Inga Larsen Center for Great Lakes Studies, Milwaukee, WI, United States Brenda Little Kenneth H. Nealson Richard Ray Alain Stone Juihan Tian Publisher: Mineralogical Society of America First Online: 02 Mar 2017 Online ISSN: 1945-3027 Print ISSN: 0003-004X GeoRef, Copyright 2004, American Geological Institute. American Mineralogist (1998) 83 (11-12_Part_2): 1564–1572. https://doi.org/10.2138/am-1998-11-1244 Article history First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation Inga Larsen, Brenda Little, Kenneth H. Nealson, Richard Ray, Alain Stone, Juihan Tian; Manganite reduction by Shewanella putrefaciens MR-4. American Mineralogist 1998;; 83 (11-12_Part_2): 1564–1572. doi: https://doi.org/10.2138/am-1998-11-1244 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyAmerican Mineralogist Search Advanced Search Abstract Previous studies have documented dissimilatory growth of bacteria on solid Mn (super 4+) oxide, but Mn (super 3+) oxides have not been previously studied; here we have demonstrated for the first time the bacterial reduction of manganite. Strain MR-4 of Shewanella putrefaciens was able to grow on and rapidly reduce insoluble needle-shaped crystals of synthetic manganite (MnOOH), converting them to soluble Mn (super 2+) in the process. The rate of Mn (super 3+) reduction was optimal at pH of 7.0 and 26 degrees C consistent with an enzymatic reaction. In addition the rates of reduction were in proportion to the amount of manganite added, but nearly independent of the cell concentration present (e.g., cell number had only a small effect on the rate of Mn (super 3+) reduction at early stages of growth) suggesting that surface properties were dictating the rates of metal reduction. This thesis was supported by major differences in reduction rates when Mn oxides of different surface areas were studied. Removal of the carbon source (formate or lactate) or addition of metabolic inhibitors reduced the rate of metal reduction. No Mn (super 3+) reduction was observed when the samples were oxygenated, nor when the cells were separated from the Mn (super 3+) oxide by a dialysis membrane. Environmental scanning electron microscopy (ESEM) images showed close contact of the cells with the needle-shaped crystals during early stages of reduction. In later stages, the closely associated cells were coated with a layer of extracellular polymeric material that obscured the cells when viewed by ESEM. When manganite crystals were dried and gold coated, and viewed by standard scanning electron microscopy (SEM), abundant bacteria could be seen on the surface of the metal oxide in a thin biofilm-like layer. The layer of extracellular polymer is a new finding, and neither the composition, function, nor importance in the manganese reduction process have been elucidated. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.