Fig. 4
Principal component analysis (PCA) of a metabolic capacities, b expressed pathways, and c individual genes/functions for active species. a PCA of active species and their metabolic capacities: proteases and glycosylhydrolases (GHs) as the number of families encoded in the genome; FA, AA, and sugar degradation as the number of pathways encoded in the genome; electron transfer/energy conservation pathways (i.e., Rnf, Nfn, Fix, Efd, and FloxHdr) as the number of pathways encoded in the genome; H2 and formate generation as presence/absence; and cytochrome bd oxidase-mediated O2 respiration as presence/absence. Individual species (points) and metabolic capacities (vectors) are shown. Confidence ellipses (95%) are shown for MAGs belonging to specific phyla. b PCA of active species and the metabolic behavior they expressed: proteases and glycosylhydrolases (GHs) as the number of families expressed in at least one reactor; FA, AA, and sugar degradation as the number of complete pathways expressed in at least one reactor; electron transfer/energy conservation pathways (i.e., Rnf, Nfn, Fix, Efd, and FloxHdr) as the number of pathways expressed in at least one reactor; H2 and formate generation as the highest hydrogenase/formatted dehydrogenase subunit expression level (calculated as RPKM normalized to specie’s non-zero median expression level); and cytochrome bd oxidase-mediated O2 respiration as the highest oxidase subunit expression level. Individual species (points) and metabolic capacities (vectors) are shown. c PCA of active species and their functional profiles predicted through eggNOG. Functions that are detected at a significantly higher frequency in Desulfobacterota and Spirochaetota than other phyla (p < 0.05) are shown as vectors. The functions associated with these vectors are shown in Table S16