Microaerophilic, Fe(II)-dependent growth and Fe(II) oxidation by a Dechlorospirillum species

• Published in: FEMS microbiology letters Vol. 319; no. 1; pp. 51 - 57
• Main Authors: Picardal, Flynn W., Zaybak, Zehra, Chakraborty, Anirban, Schieber, Jürgen, Szewzyk, Ulrich
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01-06-2011; Wiley-Blackwell; Oxford University Press
• Subjects: Acetic acid; Aerobiosis; Biological and medical sciences; Community involvement; Dechlorospirillum; Ferrous Compounds - metabolism; ferrous iron; Fresh Water - microbiology; Fundamental and applied biological sciences. Psychology; gradient culture; Inoculum; Iron; iron cycle; iron oxidation; Microbial activity; Microbiology; Microorganisms; Nitrates; Oxidation; Oxidation-Reduction; Oxygen - metabolism; Perchlorate; Perchloric acid; Phylogeny; Redox properties; Rhodospirillaceae - classification; Rhodospirillaceae - growth & development; Rhodospirillaceae - isolation & purification; Rhodospirillaceae - metabolism; Sediments; Species; Sulfides; Transition zone; iron cycle; iron oxidation; gradient culture; ferrous iron; Oxygen; Iron; Oxidation
• ISSN: 0378-1097; 1574-6968
• DOI: 10.1111/j.1574-6968.2011.02265.x

Abstract
A species of Dechlorospirillum was isolated from an Fe(II)-oxidizing, opposing-gradient-culture enrichment using an inoculum from a circumneutral, freshwater creek that showed copious amounts of Fe(III) (hydr)oxide precipitation. In gradient cultures amended with a redox indicator to visualize the depth of oxygen penetration, Dechlorospirillum sp. strain M1 showed Fe(II)-dependent growth at the oxic–anoxic interface and was unable to utilize sulfide as an alternate electron donor. The bacterium also grew with acetate as an electron donor under both microaerophilic and nitrate-reducing conditions, but was incapable of organotrophic Fe(III) reduction or nitrate-dependent Fe(II) oxidation. Although members of the genus Dechlorospirillum are primarily known as perchlorate and nitrate reducers, our results suggest that some species are members of the microbial communities involved in iron redox cycling at the oxic–anoxic transition zones in freshwater sediments.