Identifying the abundant and active microorganisms common to full-scale anaerobic digesters

Abstract

Anaerobic digestion is widely applied to treat organic waste at wastewater treatment plants. Characterisation of the underlying microbiology represents a source of information to develop strategies for improved operation. To this end, we investigated the microbial community composition of thirtytwo full-scale digesters over a six-year period using 16S rRNA gene amplicon sequencing. Sampling of the sludge fed into these systems revealed that several of the most abundant populations were likely inactive and immigrating with the influent. This observation indicates that a failure to consider immigration will interfere with correlation analysis and give an inaccurate picture of the active microbial community. Furthermore, several abundant OTUs could not be classified to genus level with commonly applied taxonomies, making inference of their function unreliable. As such, the existing MiDAS taxonomy was updated to include these abundant phylotypes. The communities of individual plants surveyed were remarkably similarwith only 300 OTUs representing 80% of the total reads across all plants, and 15% of these identified as likely inactive immigrating microbes. By identifying the abundant and active taxa in anaerobic digestion, this study paves the way for targeted characterisation of the process important organisms towards an in-depth understanding of the microbial ecology of these biotechnologically important systems.

Understanding the performance of an AnMBR treating urban wastewater and food waste via model simulation and characterization of the microbial population dynamics

“…[28]. This assumed metabolic potential has also been suggested in other studies that analyzed the microbial diversity in mesophilic anaerobic digesters [29,30]. Finally, the well described acetoclastic methanogenic capacity of the Methanosaeta genus could be attributed to the high SMA values determined in Periods 4 and 5.…”

A year of monitoring 20 mesophilic full-scale bioreactors reveals the existence of stable but different core microbiomes in bio-waste and wastewater anaerobic digestion systems

“…Recently, through the use of 16S ribosomal RNA (rRNA) gene high-throughput amplicon sequencing and/or metagenomics, a number of studies have attempted to explore the microbial community ecology of AD, e.g. [ 3 , 8 – 14 ]. Although these studies have provided great insights into the structure, dynamics and functionality of microbial communities, most of them were limited to the municipal/industrial wastewater installations or farm reactors where animal manure and/or energy crops were the main feeding substrates.…”

“…viral predation [ 20 ], a stable core community composed of roughly 63 abundant genus-level operational taxonomic units (OTUs), accounting for 68% of relative community abundance, has recently been reported for activated sludge ecosystem [ 21 ]. Six-year monitoring survey of 32 Danish full-scale AD reactors also showed that out of the huge diversity of microbes merely 300 OTUs represented 80% of total rRNA reads across reactors [ 8 ]. While, the high overall diversity of microbes reported in different studies (e.g.…”

MiDAS 2.0: an ecosystem-specific taxonomy and online database for the organisms of wastewater treatment systems expanded for anaerobic digester groups

“…thermophilic anaerobic digesters. Amplicon abundance values (V1-3 region) are given as a percentage of total bacterial reads for the influent wastewater, activated sludge and anaerobic digester communities (19). *Novel MiDAS genus level taxa are given in bold.

Figure 3.Box plot for the distribution of the 10 most abundant archaeal genus-level-taxa by median abundance in A .

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“…Sequences for all datasets (19) are classified with the MiDAS taxonomy v. 2.1.aSequences from all plants.bGenus level taxa not included in the base SILVA 123 taxonomy.…”