Fig 1.
Venn diagram of the shared microorganisms in PTA-watewater treatment UASB granules.
Syntrophs and methanogens are highlighted by green and blue, respectively.
Fig 2.
Jackknife-supported Principal coordinate analysis plots with weighted UniFrac in (A) All reactors, (B) reactor E, and (C) reactor U1. GSA, GSB, and GSC indicate small (1–2 mm), medium (2–3 mm), large (3–4 mm), respectively. For these analyses, 16S rRNA sequence reads were normalized to 18,000 reads per sample. “Cluster” of each granule type is supported by Jackknife-supported weighted UniFrac tree (S1 File).
Fig 3.
Abundance of predominant OTUs in reactors E, F and U1 using bubble plots.
Circle sizes correspond to abundance rate, as shown at the bottom of the figure. Circle lines indicate the statistical differences of OTU abundance between different granule types based on Welch’s t-test (p<0.05).
Fig 4.
Boxplots of observed OTUs (lower box plots) and Chao1 (upper box plots).
The dash lines indicate the statistical differences based on unpaired Welch’s t-test. The gray and black lines are p-value <0.05 in Chao1 and observed OTUs and p-value <0.05 in observed OTUs.
Fig 5.
Network of predominant microorganisms in reactor E based on Spearman’s correlation analysis(Spearman’s rs > 0.4 and p-value < 0.001).
Highlighted blue and green lines indicate the positive correlations between methanogens and syntrophs and strong positive correlations between “Candidatus Aminicenantes” and Methanosaeta (rs > 0.7), respectively. Light blue and light orange lines indicate the positive and negative correlations, respectively. Circle sizes correspond to average abundance rate, as shown at the left bottom of the figure. Orange circle color shows the methanogens nodes including Methanosaeta (MS), Methanomethylovorans (MV), Methanobacterium (MB), Methanolinea (ML), and Methanomassiliicoccus (MM). Light green circle color shows the syntrophs nodes including Syntrophaceae (SPH) and Syntrophorhabdacea (SHB). Bacteroidales (BCT), Rikenelaceae (RIK), and Treponema (TPN) were indicated with light brown, dark gray, and brown circle colors, respectively.