Relative abundance (as determined by 16S rRNA gene amplicon sequencing) of the prokaryotic phyla in different enrichments incubated with specific carbon substrates (acetate, pyruvate, amino acid mixture, D-galactose, D-cellobiose, cellulose) at different growth conditions (i.e., 1–4 mM of sulfide at 10–20 °C). A repeated subculturing and streaking on various growth media from the master enrichment (A-viii and x) resulted in the pure (strains affiliated to the phyla Fusobacteriota , Bacillota , Spirochaetota , Bacteroidota ) and enrichment cultures ( Cloacimonadota , Planctomycetota , Ignavibacteriota , and Mycoplasmatota ) of novel piezotolerant anaerobic bacteria.
