Microbial communities in an anaerobic dynamic membrane bioreactor (AnDMBR) for municipal wastewater treatment: Comparison of bulk sludge and cake layer

Abstract

454 high-throughput pyrosequencing was employed to investigate microbial communities in bulk sludge (BS) and cake layer (CL) in an anaerobic dynamic membrane bioreactor (AnDMBR). Pyrosequencing produced 7402 and 7026 high-quality V1–V3 tags of the 16S rRNA-gene for the BS and CL samples, and the number of total OTUs estimated by Chao1 was 2906 (BS) and 2532 (CL) at a 3% distance. Phylogenetic spectrum and Venn diagrams revealed that the bacterial phyla in the two samples were nearly identical, and that the predominant microorganisms of them exhibited a high homology. Nevertheless, population distribution was different between them. Proteobacteria were the most dominant in the BS, while Bacteroidetes, Firmicutes and Spirochaetes were highly enriched in the CL, accounting for 57.6% of the total microbes. The main microbial groups in the CL were highly functionally organized. Bacteroides, Clostridia and Delta-proteobacteria were likely the pioneers for surface colonization on membranes in the AnDMBR.