Fig. 5. Relative abundance of known and novel syntrophic bacterial genera in (a) full-scale digesters and (b) the SCFA stimulated reactors.

Data are based on 16S rRNA gene amplicon sequencing of DNA extracted from digester slurry. The full-scale data were based upon 103 samples collected from 30 full-scale digesters at 18 Danish WWTPs in 2016 year with 2 to 12 samples per digester [8]. The numbers in the heatmap are average relative read abundance in percentage for each WWTP. The THP digesters are operated at mesophilic conditions, but the substrates are thermally hydrolyzed prior to anaerobic digestion. The lab-scale data were derived from analyses on the inoculum and biomass sampled 2 h after each SCFA addition, with two samples for each condition. Taxonomic classification was based on the SILVA taxonomy. The novel syntrophic genera described in this study are highlighted in red.