Fig. 9

The microbial composition of bacteria (a,b) and archaea (c and d) at phylum and genus levels at 40 days (exponential phases of gas production). T_1 represents hydrothermal pretreatment (30 min, 150 °C). T_2 represents hydrothermal-alkaline pretreatment (0.2 mol/L NaOH, 30 min, 150 °C).