The aim of this study was to evaluate the effect of different inoculum sources on the rice straw anaerobic digestion. Six different digestates (DM, SM, CM, MS, AGS and PS) were applied as inoculums and their effects were evaluated in batch reactors. The results indicated that digested manures were more suitable than sludge. Reactors inoculated with digested manures achieved higher, biogas production and lignocellulose degradation. The better adaptability of digested manures had relationship with its higher cellulase and xylanase activities and sufficient nutrients content. DM had the best effect among all three digested manures. Reactors inoculated with DM achieved the highest biogas production (325.3 mL/g VS) and enzymes activities. The synergism between cellulase and xylanase activities played an important role in lignocellulose degradation. (C) 2014 Elsevier Ltd. All rights reserved.