| description |
Dissimilatory sulfate reduction mediated by sulfate-reducing microorganisms (SRMs) has a pivotal role in the sulfur cycle, from which the generation of zero valent sulfur (ZVS) represents a novel pathway. Details in the sulfite reduction to sulfide has been still in debate, which might involve a series of intermediates, in particular thiosulfate, trithionate and bisulfite. Moreover, the microbial community, physiology and the metabolism role of theses bacteria remain a mystery. We use genome-resolved metagenomics to build up an ecological model of SRMs in a lab-scale light-blocking methanogenic bioreactor system (ZVS-SR bioreactor) with stable operation for more than 400 days. Here our results yield 51 metagenome assembled genomes (MAGs) from the ZVS-SR bioreactor and most of they were mapped to the phyla Proteobacteria. The major players for ZVS generation included Desulfobacter, Desulfococcus, Desulfobacula and Desulfobacterales, which employed a complete gene set (i.e., satA, aprA, aprB, dsrA, dsrB, dsrC and dsrD) for the dissimilatory sulfate reduction. Desulfobacterales (SRB-bin23) was chosen for subsequent detailed characterization of genome-encoded metabolic pathways. This study expands our understanding of the SRMs-mediated dissimilatory sulfate reduction and may have important implications in environmental bioremediation. |