Fig. 4From: Adaptation of a microbial community to demand-oriented biological methanationPrincipal component analysis (PCA) of the biogas microbiome to identify changes in the metabolic activity for two H2-feeding experiments (BM-24/0, filled rectangle and BM-12/12, filled circle). To avoid an overcrowded PCA plot, only the mean values of the samples of these two H2-feeding regimes are shown. See details of PCA plot data generation in Additional file 6Back to article page