Fig. 7
Cumulative methane production during (a) and total methane production (b) after 28 days of thermophilic incubation from reactors reflecting different overload conditions (low, medium, high). Cont control, Tryp tryptophan, Tyr tyrosine, Phe phenylalanine, ME meat extract, Cas casein. *Significantly different from control: conover test, α = 0.01, H0 rejected if p ≤ α/2