title: Effect of growth conditions on microbial activity and iron-sulfide production by Desulfovibrio vulgaris.
abstract: Sulfate-reducing bacteria (SRB) can produce iron sulfide (FeS) solids with mineralogical characteristics that may be beneficial for a variety of biogeochemical applications, such as long-term immobilization of uranium. In this study, the growth and metabolism of Desulfovibrio vulgaris, one of the best-studied SRB species, were comprehensively monitored in batch studies, and the biogenic FeS solids were characterized by X-ray diffraction. Controlling the pH by varying the initial pH, the iron-to-sulfate ratio, or the electron donor - affected the growth of D. vulgaris and strongly influenced the formation and growth of FeS solids. In particular, lower pH (from initial conditions or a decrease caused by less sulfate reduction, FeS precipitation, or using pyruvate as the electron donor) produced larger-sized mackinawite (Fe1+xS). Greater accumulation of free sulfide, from more sulfate reduction by D. vulgaris, also led to larger-sized mackinawite and particularly stimulated mackinawite transformation to greigite (Fe3S4) when the free sulfide concentration was 29.3mM. Furthermore, sufficient free Fe(2+) led to the additional formation of vivianite [Fe3(PO4)2·8(H2O)]. Thus, microbially relevant conditions (initial pH, choice of electron donor, and excess or deficiency of sulfide) are tools to generate biogenic FeS solids of different characteristics.
authors.affiliation: Swette Center for Environmental Biotechnology, Biodesign Institute, Arizona State University, USA. Electronic address: chen.zhou.2@asu.edu.
authors.forename: Chen
authors.initials: C
authors.lastname: Zhou
authors.affiliation: Swette Center for Environmental Biotechnology, Biodesign Institute, Arizona State University, USA.
authors.forename: Raveender
authors.initials: R
authors.lastname: Vannela
authors.affiliation: Department of Civil and Environmental Engineering, University of Michigan, USA.
authors.forename: Kim F
authors.initials: KF
authors.lastname: Hayes
authors.affiliation: Swette Center for Environmental Biotechnology, Biodesign Institute, Arizona State University, USA.
authors.forename: Bruce E
authors.initials: BE
authors.lastname: Rittmann
mesh_terms: D000890:Anti-Infective Agents / Q000737:chemistry*; D001673:Biodegradation, Environmental; D003460:Crystallization; D016969:Desulfovibrio vulgaris / Q000254:growth & development / Q000378:metabolism*; D004583:Electrons; D005296:Ferrous Compounds / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D013431:Sulfates / Q000737:chemistry; D013440:Sulfides / Q000737:chemistry; D013816:Thermodynamics; D014874:Water Pollutants, Chemical; D018508:Water Purification; D014961:X-Ray Diffraction
chemical_list: D000890:Anti-Infective Agents; D005296:Ferrous Compounds; D013431:Sulfates; D013440:Sulfides; D014874:Water Pollutants, Chemical; C022597:ferrous sulfide
keywords: Desulfovibrio vulgaris; Greigite; Mackinawite; Sulfate reduction; Vivianite