16SrRNA of sulfodogenic reactor
After genomic DNA extraction, PCR amplification was performed targeting the V4V5 region of the bacterial 16S rRNA gene, using the primer pairs 515F-806R for bacteria and 341F-785R for archaea [24,38]. Sequencing was conducted at MR DNA (www.mrdnalab.com, Shallowater, TX, USA) using an Ion Torrent PGM, following the manufacturers protocols. The obtained sequences were processed through a proprietary analysis pipeline provided by MR DNA. Briefly, barcodes and primers were removed, and sequences shorter than 150 bp, those containing ambiguous base calls, or homopolymer runs longer than six bases were discarded.