Fig. 6

Canonical correspondence analysis (CCA) of the microbial community ordinated at the OTU level. Samples correspond to mixed substrate (GG_CO2) at 5 bar pCO₂, mixed substrate control at 5 bar pN₂ (GG_N2) and single substrate controls (glucose GLU_CO2 and glycerol GLY_CO2). Significant correlations between community composition and operational conditions: elevated pCO₂ (P), presence of formate as additional electron donor (F), carboxylate concentrations (acetate (Ac), propionate (Pr), butyrate (Bu)) and cell density concentrations (CD normalized to the log₁₀) are depicted as blue arrows