Impact of lignocellulosic-waste intermediates on hydrolysis and methanogenesis under thermophilic and mesophilic conditions

•Furfural, HMF, vanillin and humic acid were chosen as potential inhibitors.•Various thermophilic and mesophilic batch tests were done during SMA and CMP tests.•Furfural and HMF fully inhibited the SMA assays at 2.0g/L under both conditions.•Vanillin and humic did not inhibit the SMA assays at 2.0g/L under both conditions.•Propionate accumulation was found in the thermophilic CMP tests for furfural and HMF.