Desulfuromonas carbonis sp. nov., an Fe(III)-, S0- and Mn(IV)-reducing bacterium isolated from an active coalbed methane gas well

Abstract

A novel, mesophilic, obligately anaerobic, acetate-oxidizing, dissimilatory iron-, sulfur-, and manganese-reducing bacterium, designated strain ICBMT, was obtained from an active, coalbed methane gas well in Indiana, USA. Strain ICBMT was a Gram-stain-negative, non-spore-forming, rod-shaped, non-motile bacterium that was rich in c-type cytochromes and formed red colonies in solid medium. Strain ICBMT conserved energy to support growth from the oxidation of acetate, propionate, pyruvate, malate, fumarate, succinate and dl-lactate, concomitant with dissimilatory iron reduction. Strain ICBMT fermented fumarate yielding succinate and acetate. Strain ICBMT was able to grow in the temperature range of 10 °C to 37 °C, NaCl concentration range of 0 to 1.2 M, and pH range of 6.5 to 8.0. The physiological characteristics of strain ICBMT indicated that it belongs to the Desulfuromonas cluster. The G+C content of its genomic DNA was 61.2 mol%. The predominant cellular fatty acids were C16 : 0 (39.3 %), C16 : 1ω7c and/or iso-C15 : 0 2-OH (36.6 %). The closest cultured phylogenetic relative of strain ICBMT was Desulfuromonas michiganensis BB1T with only 95 % 16S rRNA gene sequence similarity. This confirmed that strain ICBMT is affiliated with the genus Desulfuromonas . On the basis of phenotypic and genotypic differences between strain ICBMT and other taxa of the genus Desulfuromonas , strain ICBMT represents a novel species for which the name Desulfuromonas carbonis sp. nov. is proposed (type strain ICBMT = DSM 29759T = JCM 30471T). Strain ICBMT is the first Fe(III)-, S0-, and Mn(IV)-reducing bacterium that was isolated from a coal bed.