Figure 1: (a) Daily methane production of untreated [U], alkaline [A] andcombined pretreated [A+B10] rice straw (b), Cumulative methane productionof untreated [U], alkaline [A] and combined pretreated [A+B10] rice straw; [U]is untreated rice straw; [A] is rice straw pretreated with 1.5M NaOH; [A+B10]is rice straw pretreated with 1.5M NaOH followed by biological pretreatmentfor 10 days.