title: Alkaline Fe(III) reduction by a novel alkali-tolerant Serratia sp. isolated from surface sediments close to Sellafield nuclear facility, UK.
abstract: Extensive denitrification resulted in a dramatic increase in pH (from 6.8 to 9.5) in nitrate-impacted, acetate-amended sediment microcosms containing sediment representative of the Sellafield nuclear facility, UK. Denitrification was followed by Fe(III) reduction, indicating the presence of alkali-tolerant, metal-reducing bacteria. A close relative (99% 16S rRNA gene sequence homology) to Serratia liquefaciens dominated progressive enrichment cultures containing Fe(III)-citrate as the sole electron acceptor at pH 9 and was isolated aerobically using solid media. The optimum growth conditions for this facultatively anaerobic Serratia species were investigated, and it was capable of metabolizing a wide range of electron acceptors including oxygen, nitrate, FeGel, Fe-NTA and Fe-citrate and electron donors including acetate, lactate, formate, ethanol, glucose, glycerol and yeast extract at an optimum pH of c. 6.5 at 20 °C. The alkali tolerance of this strain extends the pH range of highly adaptable Fe(III)-reducing Serratia species from mildly acidic pH values associated with acid mine drainage conditions to alkali conditions representative of subsurface sediments stimulated for extensive denitrification and metal reduction.
authors.affiliation: Research Centre for Radwaste and Decommissioning and Williamson Research Centre for Molecular Environmental Science, School of Earth, Atmospheric and Environmental Sciences, The University of Manchester, Manchester, UK.
authors.forename: Clare L
authors.initials: CL
authors.lastname: Thorpe
authors.forename: Katherine
authors.initials: K
authors.lastname: Morris
authors.forename: Christopher
authors.initials: C
authors.lastname: Boothman
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Lloyd
mesh_terms: D000468:Alkalies / Q000378:metabolism*; D001673:Biodegradation, Environmental; D005290:Ferric Compounds / Q000378:metabolism*; D019015:Geologic Sediments / Q000737:chemistry / Q000382:microbiology*; D006863:Hydrogen-Ion Concentration; D008969:Molecular Sequence Data; D055848:Nuclear Power Plants; D010084:Oxidation-Reduction; D010802:Phylogeny; D012705:Serratia / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D006113:United Kingdom
chemical_list: D000468:Alkalies; D005290:Ferric Compounds