16S rRNA pyrosequencing dataset of anaerobic biofilm microbial communities under silver exposure conditions

This dataset contains 16S rRNA pyrosequencing data and microbial community analysis of anaerobic biofilms developed in inverse fluidized bed bioreactors employed for silver recovery processes. The dataset includes raw and processed sequencing files, operational taxonomic unit (OTU) tables, taxonomic classification outputs, rarefaction analyses, sequence quality statistics, alignment quality reports, and taxonomic fingerprint visualizations generated through the SILVAngs pipeline. Two anaerobic biofilm DNA samples were analyzed under different experimental conditions. DNA_1 corresponds to anaerobic biofilm exposed to silver during the recovery process (0.266 g biomass), while DNA_2 corresponds to anaerobic biofilm developed in the absence of silver exposure (0.2797 g biomass). These samples were evaluated to investigate the effect of silver presence on microbial community composition and diversity in anaerobic bioreactor systems. High-throughput pyrosequencing targeted the small subunit (SSU) 16S rRNA gene to characterize microbial populations associated with anaerobic silver recovery conditions. Sequence processing and taxonomic classification were performed using the SILVAngs 1.2 pipeline and the SILVA SSU rRNA reference database (release 119.1). Quality control included removal of sequences with low alignment quality, excessive ambiguities, homopolymers, or insufficient aligned length. Dereplication, OTU clustering (98% similarity), and taxonomic classification were subsequently conducted using CD-HIT, BLAST, and SILVA reference alignments. The dataset contains 6,378 total sequences, of which 98.81% were successfully classified taxonomically, generating 202 OTUs representative of anaerobic microbial diversity associated with the evaluated bioreactor system. Taxonomic profiles include members of Proteobacteria, Firmicutes, Chloroflexi, Bacteroidetes, Euryarchaeota, and other microbial groups relevant to anaerobic environmental processes. Included files comprise FASTA/FNA sequence files, OTU abundance tables, rarefaction datasets, taxonomic breakdown analyses, Krona-compatible visualizations, quality control summaries, statistical outputs, and automated SILVAngs reports. These data support studies related to anaerobic biofilms, microbial ecology, environmental biotechnology, metal recovery systems, microbial response to silver exposure, and bioreactor-based bioremediation processes. The dataset was generated as part of a Master’s thesis focused on microbial communities associated with anaerobic silver recovery systems and environmental biotechnology applications.