Fig. 6

NMDS plot analyses of the methanogenic T-RFLP profiles and its correlation with reactor parameters. The hulls show the effect of the inoculation strategy (MIX vs. FCM) using the co-digestion setup (a), and the effect of the substrate (mono vs. co-digestion) applying MIX inoculum (b). The data points are numbered according to specific sampling days. The blue arrows indicate the highly significant (p < 0.001) methanogens, whereas the black arrows represent the highly significant (p < 0.001) reactor parameters as correlation vectors of the methanogenic community dynamics. The arrow length shows the correlation with the ordination axis, while the arrow direction corresponds to the community structures