[Phylogenetic diversity of dissimilatory Fe(III)-reducing bacteria in paddy soil]

Microorganism-mediated dissimilatory Fe (III) reduction is recognized as the dominant mechanism for Fe(III) reduction to Fe(II) in non-sulfidogenic anaerobic environments, but the microorganisms involved, especially in paddy soil, are still poorly understood. In this paper, an enrichment culture was conducted to study the phylogenetic diversity of Fe (III)-reducing bacteria in paddy soil, with acetate or hydrogen as the electron donor and with ferrihydrite or goethite as the electron acceptor, and by the methods of terminal-restriction fragment length polymorphism (T-RFLP) technology and 16S rRNA genes cloning and sequencing. No matter what the electron donor and electron acceptor were supplemented, the most abundant microorganisms were Geobacter and Clostridiales, and Rhodocyclaceae were also abundant, when acetate was supplemented as electron donor, which suggested that besides Geobacter, Clostridiales and Rhodocyclaceae could be also the important Fe(III)-reducing bacteria in paddy soil.