A site-specific curated database for the microorganisms of activated sludge and anaerobic digesters

An understanding of the microbial communities and dynamics in wastewater treatment systems is a powerful tool for process optimization and design. The advent of amplicon sequencing of the 16S rRNA gene now allows the diversity within the microbial communities to be sampled sufficiently to describe the composition and dynamics of the most abundant organisms. However, to understand the relationship between the population dynamics and operational parameters of the system, a functional role must be attributed to each organism. The Microbial Database for Activated Sludge (MiDAS) and Anaerobic Digesters (AD) presented here provides a site specific curated taxonomy for abundant and important microorganisms and integrates it into a community knowledge web platform about the microbes in activated sludge (AS) and their associated ADs (www.midasfieldguide.org). The MiDAS taxonomy, a manual curation of the SILVA taxonomy, proposes putative names for each genus-level-taxon that can be used as a common vocabulary for all researchers in the field. The online database covers >250 genera found to be abundant and/or important in biological nutrient removal treatment plants, based on extensive in-house surveys with 16S rRNA gene amplicon sequencing (V1-3 region), including full-scale AS (20 plants, 8 years) and AD systems (36 reactors, 18 plants, 4 years). Surveys also include the Archaea (V3-5 region). The MiDAS field guide is intended as a collaborative platform for researchers and wastewater treatment practitioners, to improve the classification of unknown organisms and link these names to the wealth of present and future functional information about their ecology.