Fig. 6From: Conversion of H2 and CO2 to CH4 and acetate in fed-batch biogas reactors by mixed biogas community: a novel route for the power-to-gas conceptThe amount of CO2 injected daily (red) and the residual CO2 concentration in the headspace after 24 h (dashed blue). The reactors received no external substrate. Experimental conditions as in Fig. 5 Back to article page